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  5. 面向高比能全固态锂金属电池的电解质界面工程关键技术研究

面向高比能全固态锂金属电池的电解质界面工程关键技术研究

深度研究匿名用户发表于 2026年05月06日 15:0099阅读
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1. 研究背景与立项意义

1.1 全固态锂金属电池的产业需求与发展瓶颈

当前，锂离子电池已广泛应用于消费电子产品，并成为电动汽车的核心动力来源，推动了产业的巨大变革1。然而，传统液态锂离子电池的有机电解液存在易燃、易爆的安全隐患，热失控风险难以完全消除，且其能量密度已接近理论极限，难以满足电动汽车日益增长的续航里程和储能系统对高能量密度的需求23。例如，在军事应用中，电池的耐火性、防爆性以及避免发热暴露位置等安全特性至关重要，而液态锂电池在这方面存在固有缺陷3。

全固态锂金属电池（ASSLMBs）以其固态电解质替代了传统有机液态电解液，从根本上解决了电池的安全问题，被认为是下一代高能量密度储能器件的理想选择24。它具有不易燃、无泄漏、工作温度范围宽等优点，能够有效抑制锂枝晶生长，并可匹配高比容量的锂金属负极和高电压正极材料，从而显著提升电池的能量密度和安全性56。这使得全固态电池在电动汽车、航空航天以及大规模储能等对安全性、能量密度和循环寿命有极高要求的领域展现出巨大的应用潜力78。

尽管全固态锂金属电池展现出巨大前景，其商业化进程仍面临诸多挑战，其中最核心的问题之一是固态电解质与电极之间界面性能不足24。高界面阻抗、界面接触不良、界面副反应以及锂枝晶形成等问题，严重影响了电池的倍率性能、循环寿命和安全性5910。这些界面问题导致电池在实际运行中容量快速衰减，无法在高电流密度下稳定工作，成为制约全固态锂金属电池大规模商业化应用的关键瓶颈。因此，开展电解质界面工程研究，是推动全固态锂金属电池走向实际应用的关键。

1.2 三类固态电解质的界面研究必要性

固态电解质是全固态锂金属电池的核心组成部分，其性能直接决定了电池的整体表现。目前，研究和开发主要集中在硫化物、氧化物和聚合物三类固态电解质。

硫化物固态电解质以其优异的室温离子电导率（可达10$^{-2}$ S cm$^{-1}$）和良好的柔韧性备受关注，其中硫代磷酸锂（LiPS）体系是代表，其导电率甚至超越了部分液态电解液，且易于成膜 111213。硫化物电解质的锂离子结合能和电负性较小，原子半径较大，这使其具有高离子导电性，在实际应用中具有吸引力 11。这些特性使其在构建高能量密度全固态电池方面具有巨大潜力。然而，硫化物电解质存在对空气敏感性高、电化学窗口窄以及与电极之间界面稳定性差等问题，尤其是在与高电压正极和锂金属负极接触时易发生副反应，导致界面阻抗升高和容量衰减 111314。

氧化物固态电解质，如石榴石型（LLZO）和NASICON型（LAGP），具有良好的化学稳定性和较宽的电化学窗口，且不易燃，安全性高 1415。特别是LLZO，在与锂金属直接接触时表现出良好的稳定性 16。然而，氧化物电解质通常存在室温离子电导率相对较低（10$^{-4}$ - 10$^{-3}$ S cm$^{-1}$）、机械性能较脆以及与电极的固-固接触不良等问题 1517。由于其刚性性质，难以与电极形成紧密的物理接触，导致较大的界面电阻 14。此外，晶界的存在也可能成为锂离子传输的障碍，增加整体阻抗 15。

聚合物固态电解质（如基于聚环氧乙烷，PEO）具有优异的柔韧性、加工性能和与电极良好的物理接触，能够有效缓解电极在充放电过程中的体积变化所产生的应力 18。PEO基聚合物电解质的离子传导机制依赖于锂盐在聚合物链段中的溶解和迁移，其最大的缺点是在室温下离子电导率较低（通常低于10$^{-5}$ S cm$^{-1}$），难以满足高倍率性能需求 18。同时，聚合物电解质与高电压正极材料的兼容性有限，且在循环过程中可能发生界面副反应，以及锂枝晶穿透问题 1819。

尽管这三类固态电解质各有优缺点，但它们都面临一个共同且核心的挑战——电解质与电极之间的界面问题。无论何种固态电解质，其与正负极材料的兼容性、界面稳定性、离子传输效率以及机械接触特性，都直接影响着全固态电池的循环寿命、倍率性能和能量密度 14。界面处的化学副反应、物理接触不良、空间电荷层效应以及锂枝晶生长等问题是普遍存在的现象 142021。因此，界面工程作为一种跨越性技术，对于提升硫化物、氧化物和聚合物电解质在全固态电池中的性能至关重要。通过精细的界面设计与调控，旨在优化固-固界面的离子/电子传输，抑制副反应，提高界面机械稳定性，从而实现这三类固态电解质在高比能全固态锂金属电池中的高性能适配与应用。

2. 典型固态电解质的界面问题与演化机制

2.1 硫化物固态电解质界面失效特征

硫化物固态电解质因其高离子电导率被视为全固态电池中最具潜力的电解质之一。然而，其在实际应用中面临多方面的界面失效挑战，主要体现在与高电压正极的化学副反应、与锂金属负极的界面还原以及固-固接触应力衰减等方面，这些问题导致电池阻抗升高和容量快速衰减。

与高电压正极的化学副反应： 硫化物固态电解质，尤其是硫磷酸锂（LiPS）基电解质，普遍存在电化学窗口窄的问题，特别是在高电压正极侧。高电压正极材料（如富镍层状氧化物）的表面通常具有较强的氧化性，容易与硫化物电解质中的硫离子（S$^{2-}$）或PS${4}^{3-}$基团发生不可逆的氧化反应 22。这些副反应导致界面处形成高阻抗的绝缘层，例如Li${x}$S${y}$、Li${2}$SO${4}$和各种磷氧化合物等。这些副产物不仅阻碍了锂离子的有效传输，显著增加了界面电荷转移阻抗，还可能消耗活性正极材料和电解质，进而导致电池容量快速衰减 2324。例如，研究表明，LiCoO${2}$正极与Li${6}$PS${5}$Cl硫化物电解质之间存在强烈的界面副反应，导致界面电阻高达1061 Ω cm$^{2}$。通过在LiCoO${2}$表面涂覆Li${2}$WO$_{4}$保护层，可以将界面电阻显著降低约15倍，至68 Ω cm$^{2}$，从而提高电池的循环稳定性 25。此外，梯度氧硫磷酸盐涂层也被证明能有效抑制富镍层状氧化物正极与硫化物电解质的界面反应，提升电池性能 26。

与锂金属负极的界面还原： 硫化物电解质与锂金属负极接触时，也极易发生还原分解反应。锂金属具有极低的还原电位，会促使硫化物电解质中的硫（S）和磷（P）被还原，形成Li${2}$S、Li${3}$P等还原产物。这些产物在界面处形成不稳定的固态电解质界面（SEI）层。不均匀且不稳定的SEI层会不断生长和破裂，导致界面阻抗持续增加，并加速锂枝晶的形成和生长。锂枝晶穿透电解质会导致电池内部短路，引发安全问题 27。例如，在Li${10}$SnP${2}$S${12}$（LSPS）硫化物电解质中，与聚环氧乙烷（PEO）聚合物膜接触时，会发生分解反应，形成多硫化物、P–[S]${n}$–P桥接的PS${4}^{3-}$单元以及亚硫酸盐（SO${3}^{2-}$）等产物，这些产物表明硫化物电解质在与锂金属直接或间接接触时会发生还原分解 28。然而，通过在硫化物电解质中掺杂碘化锂（LiI），可以抑制Li${3}$PS${4}$的还原分解，维持界面稳定性，从而有效抑制锂枝晶生长 29。此外，通过聚碳酸亚丙酯（PPC）/LiTFSI缓释层在Li${6}$PS${5}$Cl与锂负极之间原位形成富含LiF的超稳定SEI，可有效抑制锂枝晶，显著提升对称电池的循环稳定性 30。

固-固接触应力衰减与界面剥离： 全固态电池中的界面是固-固接触，其接触面积和紧密程度对离子传输至关重要。硫化物电解质虽然具有一定的柔韧性，但在长期充放电过程中，电极材料（特别是锂金属负极）的体积变化会产生巨大的机械应力。这种应力可能导致电解质与电极之间的物理接触逐渐丧失，形成微观空隙，进而增大界面阻抗。此外，电极颗粒与电解质之间的机械剥离也会加剧界面接触不良，导致局部电流密度过高，促进锂枝晶的非均匀生长。这种固-固接触应力衰减是一个动态过程，随着循环进行，界面剥离效应愈发严重，最终导致电池性能迅速恶化。例如，为解决硫化物电解质的脆性问题和与电极的接触问题，研究人员通过多孔粘合剂和聚四氟乙烯（PTFE）粘结剂将硫化物电解质制备成超薄（40 µm）且高离子电导率（1.1 mS cm$^{-1}$）的自支撑膜，并设计稳定的界面，在0.2 mA cm$^{-2}$下对称电池循环800小时保持稳定，展示了机械稳定性对界面的重要性 31。

综上所述，硫化物固态电解质的界面失效特征主要源于其与高电压正极的化学不稳定性导致副反应产物堆积，以及与锂金属负极的还原分解形成不稳定SEI，并伴随充放电过程中因体积变化引起的固-固接触应力衰减和界面剥离。这些复杂的相互作用最终表现为界面阻抗的显著升高和电池容量的快速衰减，是硫化物全固态电池商业化前必须克服的核心挑战。

2.2 氧化物固态电解质界面失配机制

氧化物固态电解质，如LLZO（Li${7}$La${3}$Zr${2}$O${12}$）和LAGP（Li${1.5}$Al${0.5}$Ge${1.5}$(PO${4}$)$_{3}$），因其优异的化学稳定性、宽电化学窗口和高安全性，被认为是全固态锂电池的理想候选材料。然而，这类电解质的本征脆性和刚性，以及复杂的微观结构，导致其在实际应用中面临独特的界面失配挑战，主要表现为物理接触不良、晶界阻抗高以及循环过程中的应力开裂。

物理接触不良： 氧化物固态电解质通常为陶瓷材料，其硬度高、刚性强，难以与同样坚硬的正极材料或柔软的锂金属负极实现原子级别的紧密接触。在制造过程中，由于界面粗糙度、微观缺陷以及压制力不均匀等因素，电极与电解质之间容易形成大量的空隙和孔洞。这些不完善的固-固接触点大幅增加了界面的电阻，阻碍了锂离子的有效传输，导致整体电池的内阻过高，功率性能受限。例如，即使施加高压进行组装，氧化物固态电解质与电极之间的实际接触面积也远小于理论面积，从而使得局部电流密度过高，易引发锂枝晶的非均匀生长和界面副反应。为改善这一问题，研究人员尝试引入聚合物中间层或液态渗透剂来“软化”界面，以提高润湿性，但这些方法可能会牺牲部分固态电解质的固有优势，如安全性或高能量密度。

晶界阻抗高： 多晶氧化物固态电解质，如LLZO和LAGP，由大量晶粒组成，晶粒之间存在晶界。晶界处通常存在晶格缺陷、离子无序排列以及杂质偏析等问题，这些因素会显著降低锂离子在晶界处的迁移速率，导致晶界阻抗远高于晶粒内部的体相阻抗 32。这种高阻抗晶界在一定程度上限制了氧化物电解质的整体离子电导率，尤其是在LLZO中，锂离子在晶界处的浓度分布不均也已被观测到 33。虽然通过优化烧结工艺、掺杂以及控制晶粒尺寸等手段可以降低晶界阻抗，但要彻底消除其对离子传输的负面影响仍然是一个挑战。晶界处的电荷积累也可能导致空间电荷层的形成，进一步阻碍离子传输。

循环过程中应力开裂： 氧化物固态电解质的脆性是其固有的材料属性。在电池充放电循环过程中，电极材料会发生体积膨胀和收缩。例如，锂金属负极在嵌锂/脱锂过程中体积变化高达约200%，而正极材料（如NCM）也可能存在显著的体积变化。这些体积变化会在界面处产生巨大的机械应力。由于氧化物电解质缺乏韧性，无法有效吸收和缓解这些应力，容易导致电解质层发生应力开裂或与电极界面剥离 34。裂纹的产生不仅增加了电池内阻，还可能为锂枝晶的生长提供通道，甚至导致电池短路。此外，热循环也可能引发界面剥离，尤其是在工作温度范围较宽的应用场景中 35。这种机械失效是导致氧化物全固态电池长期循环稳定性差的关键因素。

不同氧化物体系的界面特性差异：

  • 石榴石型LLZO（如Li${7}$La${3}$Zr${2}$O${12}$）： LLZO具有较高的离子电导率（~10$^{-4}$ S cm$^{-1}$量级），且与锂金属负极表现出良好的稳定性，不易发生界面副反应。然而，LLZO的烧结温度高，制备工艺复杂，且与正极材料的界面接触问题突出。为了降低LLZO的烧结温度并提高其致密性，通常需要进行Al、Ta等元素的掺杂。但掺杂也可能引入新的界面问题。
  • NASICON型LAGP（如Li${1.5}$Al${0.5}$Ge${1.5}$(PO${4}$)$_{3}$）： LAGP电解质具有更低的制备温度，且在空气中具有较好的稳定性。其离子电导率也较高（~10$^{-4}$ S cm$^{-1}$量级）。然而，LAGP与锂金属负极的电化学稳定性较差，容易发生还原反应，形成低电导率的界面层，严重阻碍锂离子的传输。因此，在LAGP基电池中，通常需要在锂负极侧引入保护层以避免直接接触。
  • LISICON型（如Li${14}$ZnGe${4}$O${16}$）和钙钛矿型（如La${2/3-x}$Li${3x}$TiO${3}$） 氧化物电解质也正在研究中，但它们通常面临离子电导率相对较低、与锂金属负极兼容性差或存在电子导电等问题，同样需要界面工程来解决。

综上所述，氧化物固态电解质的界面问题核心在于其固有的刚性和脆性，导致物理接触不良和机械应力开裂，而晶界的高阻抗则进一步限制了离子传输效率。不同的氧化物体系由于其化学组成和晶体结构的差异，在与电极的兼容性上表现出不同的界面特性，需要针对性的界面工程策略来克服这些挑战。

2.3 聚合物固态电解质界面不稳定机理

聚合物固态电解质（Solid Polymer Electrolytes, SPEs），特别是基于聚环氧乙烷（PEO）的体系，因其优异的柔韧性、良好的加工性能、低成本以及与电极材料良好的物理接触能力而被广泛关注 363738。然而，聚合物电解质在全固态锂金属电池的应用中，仍面临界面副反应、室温离子电导率不足和锂枝晶穿透等关键不稳定因素 3839。

聚合物与电极界面的副反应： 尽管聚合物电解质被认为化学稳定性较好，但在与高电压正极和锂金属负极长期接触时，仍不可避免地发生界面副反应 40。

  • 正极侧副反应： 在高电压正极（如NCM、LCO）条件下，聚合物电解质（尤其是PEO）的醚键可能被氧化，导致聚合物链断裂，形成绝缘性副产物，从而增加界面阻抗 40。这些副反应不仅消耗了活性聚合物电解质，还会在界面形成不稳定的固态电解质界面（SEI）或正极电解质界面（CEI），阻碍锂离子的传输。为抑制这些副反应，研究常通过在正极表面构建稳定的保护层（如涂覆导电聚合物PEDOT:PSS可提高正极材料性能 41）或采用新型高稳定聚合物基体来改善。
  • 负极侧副反应： 锂金属负极具有极低的电化学电位，会促使聚合物电解质发生还原分解。这可能导致聚合物的分解，在锂负极表面形成不均匀、高阻抗的SEI膜。这种不稳定的SEI膜会持续消耗电解质和活性锂，加速电池容量衰减，并为锂枝晶的生长提供不均匀的成核位点。通过在聚合物电解质中引入具有抗还原能力的组分或构建人工SEI层可以有效缓解此问题 42。

室温离子电导不足： 大多数聚合物电解质，特别是PEO基SPEs，在室温下的离子电导率普遍较低（通常为10$^{-7}$至10$^{-5}$ S cm$^{-1}$量级），远低于液体电解液和硫化物固态电解质，难以满足高倍率充放电需求 3638。这是因为锂离子在聚合物电解质中的传输主要依赖于聚合物链段的运动（即“链段运动”机制），而PEO在室温下通常呈现半结晶态，结晶区域限制了链段运动，从而阻碍了锂离子的快速迁移。为了提高室温离子电导率，常用的策略包括：

  • 降低聚合物结晶度： 通过无定形化改性（如引入支链、共聚、交联等）来增加聚合物的无定形区，促进链段运动 3743。
  • 添加无机填料： 将纳米级陶瓷颗粒（如Li${7}$La${3}$Zr${2}$O${12}$ (LLZO) 44、Al${2}$O${3}$、SiO$_{2}$等）引入聚合物基体中，形成复合聚合物电解质（Composite Polymer Electrolytes, CPEs） 3645。无机填料可以提供额外的锂离子传输路径，并与聚合物链形成相互作用，抑制聚合物结晶，从而提高离子电导率 45。例如，在聚合物中添加NASICON型材料，可形成具有“凝胶状”局部层，促进电荷快速移动 46。
  • 增塑剂引入： 引入液态或固态增塑剂，如离子液体或塑化剂，可以增加聚合物链段的自由体积和柔韧性，从而提升离子电导率。然而，过度引入增塑剂可能会牺牲电池的安全性。

锂枝晶穿透问题： 尽管聚合物电解质具有一定的柔韧性，但其力学强度相对于锂金属在循环过程中形成的枝晶而言仍然不足。在电流密度较高或长时间循环的条件下，锂离子在负极表面不均匀沉积，会形成尖锐的锂枝晶。这些锂枝晶可以穿透聚合物电解质层，导致电池内部短路，引发热失控，严重威胁电池安全 3942。锂枝晶的形成还与界面处的离子通量分布不均匀、界面阻抗梯度以及电解质对锂金属润湿性差等因素有关 47。

复合改性对界面性能的调控逻辑： 针对上述问题，复合改性是聚合物电解质界面工程的核心策略。

  • 无机填料复合： 通过将高离子电导率的无机固体电解质（如LLZO、LAGP）纳米颗粒均匀分散到聚合物基体中，可以显著提高复合电解质的室温离子电导率和机械强度 4445。无机填料不仅提供额外的离子传输通道，还能抑制聚合物链的结晶，增强对锂枝晶生长的机械阻挡能力。此外，填料的表面活性位点还可以吸附阴离子，提高锂离子迁移数 48。
  • 原位聚合与人工SEI构建： 采用原位聚合技术，可以在电极表面形成与电极紧密接触的聚合物电解质层，有效降低界面阻抗 4249。同时，通过引入功能性添加剂或设计新型聚合物结构，可以在锂金属负极表面原位构建稳定、均匀且具有良好离子导电性的“人工SEI”层。例如，通过共聚或添加具有特定官能团的交联剂，可以调控界面SEI的化学组分和物理形貌，抑制副反应，提高界面稳定性 4250。聚合物电解质（如1,3-二氧戊环）的原位聚合能够形成具有热电化学兼容性的电解质，从而抑制界面副反应，促进均匀锂沉积 42。
  • 多孔结构与三维网络构建： 通过构建多孔或三维交联聚合物网络，可以提供丰富的锂离子传输路径，并提高电解质的机械强度和柔韧性，从而有效抑制锂枝晶穿透。

综上，聚合物固态电解质的界面不稳定主要源于其固有的室温离子电导不足、与电极材料的界面副反应以及对锂枝晶的抑制能力弱。通过复合无机填料、原位聚合、人工SEI构建等复合改性策略，旨在提高电解质的离子电导率和机械强度，构建稳定的界面结构，从而提升聚合物全固态电池的综合性能。

3. 核心关键科学问题凝练

3.1 固-固界面多尺度电荷输运衰减机制

在全固态锂金属电池中，锂离子（Li$^{+}$）和电子（e$^{-}$）在固-固界面上的有效传输是决定电池性能的关键。与液态电解液的电荷传输机制不同，固-固界面的电荷输运更加复杂，涉及多个尺度上的物理和化学过程。界面处的离子和电子输运衰减是导致高界面阻抗、低倍率性能和循环寿命衰减的核心原因。深入理解这些衰减机制，是实现高性能固态电池界面工程的基础。

离子输运衰减机制：

  1. 界面物理接触不良： 这是最直接且普遍的问题。固态电解质和电极材料通常是刚性的，难以实现原子级别的紧密接触。在微观尺度上，界面存在大量的空隙、孔洞和不规则区域，导致实际接触面积远小于理论面积。锂离子只能通过有限的接触点进行传输，有效传输路径受限，从而显著增加了界面电阻。当电极材料在充放电过程中发生体积变化时，固-固界面应力集中会导致界面剥离，进一步加剧接触不良 51。
  2. 界面化学相变与副产物形成： 固态电解质与电极之间往往存在热力学或动力学不稳定性，导致界面发生副反应，形成新的中间相或副产物层。这些副产物通常具有低离子电导率或绝缘性，形成额外的扩散势垒，严重阻碍锂离子的跨界面传输。例如：
    • 在硫化物电解质与高电压正极界面，高氧化性正极会氧化硫化物电解质，形成阻碍离子传输的绝缘相。
    • 在硫化物电解质与锂金属负极界面，锂金属的强还原性会导致硫化物分解，生成Li${2}$S、Li${3}$P等还原产物，形成不稳定的固态电解质界面（SEI）层，该层会不断生长和破裂，持续消耗活性锂离子并增加阻抗。
    • 在氧化物电解质与锂金属负极界面，虽然部分氧化物（如LLZO）与锂金属相对稳定，但仍可能发生界面反应。文献52揭示了LLZO与锂金属界面的行为，指出LLZO在与锂金属接触时可能发生Al损失和从立方相到四方相的转变，这些界面化学变化可能形成低电导率产物。文献53则关注了石榴石基固态锂金属电池中界面阻抗的消除。
    • 对于NASICON型氧化物，如LAGP，与锂金属负极则可能发生直接还原反应，形成高阻抗界面层。
    • 聚合物电解质与正负极的界面副反应类似，会形成氧化或还原产物，阻碍离子传输。
  3. 空间电荷层效应： 在异质固-固界面处，由于两侧材料的费米能级不匹配或离子缺陷浓度的差异，可能会在界面附近形成一个空间电荷层。该区域内锂离子浓度会发生变化，形成一个额外的电势梯度，阻碍锂离子的有效传输，增加界面阻抗。这种效应在氧化物电解质中尤其显著，被认为是导致界面高阻抗的重要因素之一 54。
  4. 晶界效应与缺陷传输： 对于多晶固态电解质和电极材料，晶界处通常存在大量的原子结构缺陷、无序区域和杂质偏析。这些晶界可以作为锂离子传输的快速通道，但更多情况下，它们会成为锂离子传输的障碍，导致晶界阻抗远高于晶粒内部的体相阻抗。晶界处的离子传输机制通常不同于体相，其活化能可能更高。

电子输运衰减机制：

  1. 界面电子绝缘层形成： 理想的固态电解质应是纯粹的离子导体，电子绝缘体。然而，界面副反应形成的产物层（如Li${2}$S、Li${2}$O、Li$_{3}$P等）往往具有电子绝缘性，会阻碍电子在电极内部以及电极与集流体之间的传输。虽然电解质本身应是电子绝缘的，但电极颗粒内部的电子传输通路对于实现均匀的电化学反应至关重要。
  2. 电极内部电子导电网络破坏： 复合正极材料通常包含活性材料、导电剂和固态电解质。在循环过程中，电极材料的体积变化或界面副反应可能导致导电剂（如碳材料）与活性材料颗粒的接触不良，破坏电极内部的电子导电网络，从而影响电子在电极内的有效传输 55。
  3. 电子泄漏与短路风险： 在某些情况下，固态电解质可能存在微量电子导电性，或者界面副产物层（如Li$^{+}$或Li$_{2}$S）具有一定的电子导电性，这可能导致电子泄漏，加速电解质分解，甚至引发内部短路 56。尤其是在锂枝晶穿透电解质形成电子通路时，会直接导致电池短路失效。

界面微观结构与化学组分对电荷传输的影响：

  • 微观形貌： 界面粗糙度、孔隙率、颗粒尺寸和分布等微观形貌特征直接影响固-固接触面积和离子传输路径。更平滑、更致密、更大接触面积的界面有利于降低界面阻抗。
  • 化学组分： 界面处的化学组成决定了界面相的性质，包括其离子电导率、电子电导率、机械稳定性和化学稳定性。通过界面修饰、涂层或原位反应形成的具有高离子电导率和/或电子绝缘性的界面层，可以有效改善电荷传输。例如，LiNbO$_{3}$等氧化物缓冲层可以有效减少正极/硫化物电解质界面的高阻抗 57。
  • 晶体结构与非晶态： 晶态界面的离子传输可能受到晶向、晶界特性的影响，而非晶态或无序界面可能提供更快的离子传输通道，但稳定性可能较差。例如，LiAlLaZrO中的Li离子在体相LLZO和跨界面时的活化能和扩散系数相当，表明界面动力学并非限制因素，但实际界面往往复杂得多 52。
  • 缺陷与掺杂： 界面处的缺陷浓度（如锂空位、间隙离子）和掺杂元素可以显著影响离子迁移率。通过掺杂引入高离子导电相或稳定界面相，可以有效改善界面电荷传输 58。

综上所述，固-固界面多尺度电荷输运衰减机制是一个复杂的交叉科学问题，涉及材料科学、电化学、力学和物理等多个学科。理解这些机制是开发高效界面工程策略的关键，旨在构建具有高离子/电子传输效率、低阻抗、高稳定性的固-固界面。

3.2 界面多场耦合作用与演化规律

全固态锂金属电池的固-固界面不仅仅是简单的物理接触面，而是一个复杂的动态系统，其性能和稳定性受到化学、电化学和力学等多场因素的协同作用与相互耦合的影响。理解这些多场耦合作用下界面相的生成、生长与失效过程，是实现高性能电池设计的关键科学问题。

化学-电化学耦合作用：
界面处的化学反应与电化学反应密不可分。电化学反应驱动着界面的化学组分变化，而化学环境又反过来影响电化学过程。

  1. 界面副反应与相变： 在电极与固态电解质的界面处，由于电极电位、固态电解质的电化学窗口以及材料本身的热力学不稳定性，往往会发生界面副反应，导致新相（如SEI/CEI层）的生成 59。这些副产物层的形成速率、组分、结构和均匀性，直接影响界面的离子/电子传输性能。例如，硫化物电解质在高电压正极侧的氧化分解和在锂负极侧的还原分解，会形成高阻抗的绝缘层，从而抑制锂离子的有效传输 60。氧化物电解质与锂金属的接触也可能导致界面化学反应，如LLZO中的Al损失或相变 61。这些化学相变受到局部电场分布的影响，同时又改变了界面的电化学环境。
  2. 空间电荷层： 固态电解质与电极之间费米能级的不匹配或离子缺陷浓度的差异，会在界面形成空间电荷层。该区域的电场梯度影响离子传输的活化能，从而改变电化学反应动力学。空间电荷层的形成是电化学驱动下的离子迁移和重新分布的结果，其厚度和组成又会影响界面处的局部化学电位和反应活性。

电化学-力学耦合作用：
电化学过程（如锂离子嵌入/脱出、枝晶生长）会引发电极材料的体积变化，进而产生机械应力，而这些力学效应又会反作用于电化学性能。

  1. 体积变化诱导的应力与界面接触： 在充放电过程中，合金负极（如Si）的体积变化巨大 62。正极材料（如层状氧化物）也存在相变导致的化学机械降解 63。这些体积变化在固-固界面处产生巨大的机械应力（压应力、拉应力、剪切应力），可能导致界面剥离、微裂纹产生和接触电阻增大 6465。脆性固态电解质（如氧化物电解质）在应力作用下容易开裂，为锂枝晶生长提供通路 61。而聚合物电解质虽具柔韧性，但若机械强度不足，仍可能被锂枝晶穿透。
  2. 锂枝晶生长与力学损伤： 锂枝晶的生长是一个典型的电化学-力学耦合过程。在循环过程中，不均匀的锂沉积导致尖锐的枝晶形成，这些枝晶在电场力驱动下向固态电解质内部生长，并施加局部应力，最终穿透电解质，导致电池短路 66。多物理场模拟表明，锂枝晶的内部生长会导致固态电解质的机械损伤和裂纹扩展 66。应力可以改变锂离子在电解质中的迁移速率和在电极表面的沉积行为，从而影响锂枝晶的形核和生长。多场耦合模型被用于研究锂枝晶的形核、生长以及对电池性能和安全性的影响 6768。
  3. 机械载荷对电化学性能的影响： 施加外部堆叠压力可以改善固-固界面的接触，降低界面阻抗，抑制锂枝晶生长 64。然而，过高的压力可能导致电解质材料的塑性变形或失效。同时，界面处的局部应力状态会影响锂离子的扩散系数和电荷转移反应的活化能，从而改变局部电化学反应速率。

化学-力学耦合作用：
界面处的化学变化（如SEI层的形成）也会影响界面的力学性能，反之，力学应力也会影响化学反应。

  1. SEI层力学特性与稳定性： 界面副反应形成的SEI层通常具有脆性或不均匀的力学性能。在电极体积变化产生的应力作用下，SEI层容易破裂，暴露新鲜电极表面，导致SEI层不断形成和消耗，持续消耗活性锂和电解质，并加速界面阻抗的增加。相反，具有高韧性和均匀性的SEI层能有效缓解应力，提高界面稳定性。
  2. 应力诱导的化学反应： 机械应力可能改变材料的原子排布和键合强度，从而影响化学反应的活化能或热力学平衡。例如，在应力作用下，某些固态电解质的局部区域可能更易发生分解反应。

界面稳定性评价方法：
为了量化和评估多场耦合作用下界面的稳定性，需要建立一套综合的评价方法，包括原位表征技术和理论模拟：

  1. 原位电化学阻抗谱（EIS）： 通过实时监测电池在循环过程中的EIS变化，可以动态分析界面阻抗的演变规律，区分体相阻抗、晶界阻抗和界面电荷转移阻抗，从而揭示界面失效的主要原因。
  2. 原位光学/电子显微技术： 结合电化学循环，利用原位扫描电子显微镜（SEM）、透射电子显微镜（TEM）或原子力显微镜（AFM）等技术，可以直接观察界面形貌变化、裂纹扩展、锂枝晶生长以及SEI层的形成和演变。例如，原位AFM可用于观察微米级硅负极的机械演变，包括裂纹形成和SEI膜的形成 62。
  3. 原位力学测试： 发展微纳尺度原位力学测试方法，如纳米压痕、原位应力-应变测量等，结合电化学刺激，实时评估界面材料的力学响应（硬度、弹性模量、韧性）及其在电化学循环中的变化。
  4. 超声成像技术： 作为一种非破坏性技术，超声成像可以有效探测全固态软包电池内部的界面降解和气体释放，区分接触损失和钝化层生长引起的界面电阻增加，为评估界面稳定性提供新的手段 69。
  5. 多物理场耦合模拟： 结合有限元分析、相场理论、密度泛函理论（DFT）等计算方法，建立化学-电化学-力学多场耦合模型 707172。通过模拟不同工况下界面的应力分布、离子/电子传输路径、SEI层生长动力学以及锂枝晶演化过程，预测界面失效行为，并指导材料设计。例如，通过模拟锂/固态电解质界面的孔洞演化和锂穿透，可以获得稳定操作区 71。
  6. X射线断层扫描（XCT）和中子衍射： 用于无损地三维重建电池内部结构，观测界面空隙率变化、裂纹扩展和锂枝晶生长路径。

通过整合这些表征与模拟手段，可以全面、深入地阐明固-固界面多场耦合作用下的界面相生成、生长与失效过程，为设计高稳定性和高性能的全固态锂金属电池界面提供科学依据。

3.3 大电流密度下界面锂枝晶抑制机理

锂金属负极由于其极高的理论比容量（3860 mAh g$^{-1}$）和最低的电化学电位（-3.04 V vs SHE），被视为下一代高能量密度电池的“圣杯”负极材料。然而，锂枝晶的形成和生长是制约锂金属电池，包括全固态锂金属电池商业化应用的核心挑战之一。在大电流密度条件下，锂枝晶问题尤为突出。理解锂沉积/溶解过程中界面应力、离子通量分布与锂枝晶生长的关联机制，并提出高稳定界面的构建准则，是实现高倍率、长寿命全固态锂金属电池的关键。

锂枝晶形成与生长的机理：
锂枝晶的形成是一个复杂的电化学-机械耦合过程，其根本原因在于锂离子在电解质/锂金属界面处沉积的不均匀性。在充电过程中，锂离子从电解质向锂金属负极迁移并在表面还原沉积为金属锂。如果沉积过程不均匀，就会在某些“活性位点”优先成核并生长成尖锐的枝晶或苔藓状锂。

  1. 不均匀的离子通量分布： 在大电流密度下，锂离子从固态电解质向锂负极表面的迁移速率是有限的。当局部区域的锂离子消耗速度快于补充速度时，会导致该区域附近的离子浓度梯度变大，形成不均匀的离子通量。这种不均匀性会促进锂在某些尖锐或缺陷处优先沉积，加速枝晶生长 73。电解质/电极界面接触不良（如孔隙、缺陷）或固态电解质内部存在晶界、空洞等缺陷时，会导致局部电流密度过高，形成“热点”，从而更容易诱导锂枝晶在这些区域成核和生长 74。
  2. 电解质的电化学不稳定性： 固态电解质与锂金属之间可能发生副反应，形成不稳定的固态电解质界面（SEI）层。不均匀的SEI层会导致局部电阻差异，进而引起局部电流密度不均，促进锂枝晶的非均匀生长。一些研究表明，固态电解质的电子导电性也与锂枝晶的形成密切相关，即使是微量的电子导电性，也可能成为锂枝晶生长的诱因 56。
  3. 机械性能不足： 传统的观念认为，固态电解质具有足够的机械强度可以物理抑制锂枝晶的穿透。然而，近年来大量研究表明，即使是致密的无机固态电解质也无法完全阻止锂枝晶的生长 75。锂枝晶在生长过程中会产生巨大的局部应力，可以达到吉帕斯（GPa）量级，远超许多固态电解质的断裂强度 7677。这种应力会导致固态电解质发生塑性变形，甚至产生微裂纹，为锂枝晶的进一步穿透提供路径 7476。例如，在循环过程中，锂枝晶可以在电解质内部形成并导致电解质内部裂纹扩展 78。
  4. 电解质/电极界面应力： 锂沉积和剥离过程伴随着锂负极的体积变化，这会在固-固界面处产生持续的机械应力。当应力分布不均匀时，会进一步加剧锂沉积的不均匀性。压缩应力可能会抑制锂枝晶生长，而拉伸应力则可能促进枝晶生长 79。维持稳定的界面应力是抑制枝晶的关键 76。

高稳定界面构建准则：
为有效抑制大电流密度下的锂枝晶，需要从多方面协同优化固态电解质/锂金属界面。

  1. 均匀的离子通量与局部电流密度： 这是抑制锂枝晶的根本。
    • 优化界面润湿性与接触： 提升固态电解质对锂金属的润湿性，形成致密、无空隙的界面，以确保均匀的离子通量。通过引入柔性中间层（如聚合物层 80）、液态金属层或具有良好柔韧性的复合电解质，可以有效改善界面接触，减少局部高电流密度区域 7681。
    • 构建人工SEI层： 在锂金属表面构筑具有高离子导电性、电子绝缘性且均匀致密的稳定人工SEI层，能够有效钝化锂金属表面，抑制副反应，并引导锂离子均匀沉积，从而避免枝晶成核 8283。例如，通过预沉积或涂覆方法引入LiF、Li$_{3}$N等组分可形成稳定的SEI。
    • 调控电解质内部缺陷： 降低固态电解质中的晶界、孔洞等缺陷密度，防止这些缺陷成为枝晶生长的“高速通道” 7475。
  2. 高机械强度与韧性： 固态电解质需要具备足够的机械强度来抵抗锂枝晶的穿透，同时也要有一定的韧性来缓冲电极体积变化产生的应力。
    • 增强电解质本体强度： 对于聚合物电解质，可以通过引入纳米填料（如ZrO$_{2}$ 84、LLZO）形成复合聚合物电解质（CPE），显著提高其机械模量，从而有效抑制枝晶生长 80。
    • 设计多层结构： 构建具有不同机械性能梯度的多层电解质结构，外层提供机械支撑，内层提供高离子导电性，以达到综合性能最优 8085。
    • 施加适当的堆叠压力： 外部施加的堆叠压力可以有效改善固-固界面的接触，同时对抑制锂枝晶生长具有积极作用。研究表明，在合适的堆叠压力（如5 MPa）下，可以显著提高电池的循环稳定性，抑制枝晶生长 86。
  3. 宽电化学窗口与化学稳定性： 固态电解质应在锂金属的电位下保持化学稳定，不与锂金属发生副反应，避免形成高阻抗的界面层。
    • 选择本征稳定的电解质材料： 优先选用对锂金属稳定的固态电解质体系，如石榴石型LLZO。对于还原不稳定的电解质（如硫化物和NASICON），则必须引入界面保护层。
    • 抑制电子导电性： 确保固态电解质本体及界面产物具有优异的电子绝缘性，防止电子泄漏引发局部反应或促进枝晶生长 56。

通过整合上述准则，设计具有高离子导电性、良好机械匹配性、化学稳定性且能促进均匀锂沉积/溶解的界面结构，是实现大电流密度下锂枝晶有效抑制，进而推动全固态锂金属电池实用化的关键。这需要跨学科的协同努力，结合材料设计、界面修饰、结构优化和先进表征技术。

4. 主要研究内容与技术路线

4.1 三类电解质的界面定向改性策略开发

针对硫化物、氧化物和聚合物三类固态电解质各自面临的独特界面问题，我们将开发差异化的界面定向改性策略，旨在构建高稳定性、高导电性、高机械匹配性的电解质/电极界面，以满足高电压正极和锂金属负极在全固态电池中的适配需求。

4.1.1 硫化物电解质的原位生成缓冲层技术

硫化物固态电解质以其高离子电导率备受关注，但其与高电压正极和锂金属负极界面化学不稳定，易发生副反应，导致界面阻抗急剧升高和容量快速衰减。为解决这一问题，本研究将聚焦开发原位生成缓冲层技术，通过引入功能性前驱体，在电极/电解质界面原位构筑超薄、致密且具有高离子导电性的缓冲层，以隔离电极与电解质的直接接触，抑制界面副反应。

针对正极/硫化物电解质界面：
我们将重点开发“氧化物包覆与原位反应协同”策略。

  1. 正极表面氧化物包覆改性： 选用化学稳定性和电化学稳定性优异的氧化物（如LiNbO${3}$、Li${2}$WO${4}$、Li${4}$Ti${5}$O${12}$等）作为包覆材料，采用原子层沉积（ALD）、溶液法或固相反应法，在高电压正极材料（如富镍层状氧化物）表面形成均匀致密的纳米级包覆层。这些包覆层不仅可以物理隔离正极与硫化物电解质，抑制直接化学接触，还能够作为Li$^{+}$的快速传输通道，降低界面电荷转移阻抗 87888990。
  2. 原位生成缓冲层： 在正极材料表面引入能与硫化物电解质原位反应生成稳定界面的前驱体。例如，在正极活性材料或电解质中引入少量具有合适氧化还原电位的锂盐或无机化合物，在首次充放电过程中，这些添加剂可以在正极/电解质界面处发生可控的电化学反应，原位生成一层具有高离子导电性且对硫化物稳定的钝化层，如锂超离子导体薄膜。该缓冲层应具有与两侧材料良好匹配的力学性能，以缓冲电极体积变化带来的应力。我们还将探索梯度掺杂技术，通过在正极材料制备过程中引入低成本氧化物（如NbO、TaO、LaO）前驱体，在正极表面形成梯度浓度分布的掺杂层，其在循环中可以原位形成保护层，有效抑制正极与硫化物电解质的副反应，并稳定正极晶体结构 90。文献中还提及，通过NaWO$_{4}$辅助烧结方法，可以在单晶富锂层状氧化物正极材料表面形成保护涂层，并实现Na和W原子向LLOs晶格的梯度掺杂，从而稳定晶体结构并提高Li离子扩散速率，最终增强正极的循环性能和电压稳定性 91。

针对锂金属负极/硫化物电解质界面：
我们将重点开发“人工界面层构建与多功能添加剂调控”策略。

  1. 原位聚合物/无机复合人工SEI： 利用具有亲锂基团的有机分子作为前驱体，在锂金属表面进行原位聚合，形成一层超薄、柔性且离子导电的聚合物膜。在此聚合物膜中复合纳米级无机固体电解质颗粒（如LLZO、Li${3}$N），可以显著提高人工SEI的离子电导率、机械强度和化学稳定性 929394。该复合人工SEI应具有较高的锂离子迁移数和良好的电子绝缘性，以促进锂离子均匀沉积，抑制枝晶生长。例如，通过在电解质中引入LiDFOB，可在Li${6}$PS$_{5}$Cl表面原位形成稳定的（电）化学机械界面 89。
  2. 功能性添加剂调控： 在硫化物电解质中引入少量功能性添加剂（如LiI），通过其在锂金属负极界面的优先还原或相互作用，改变界面处的电化学环境，抑制硫化物电解质的分解，并促进形成致密、稳定的界面相。例如，LiI可抑制Li${3}$PS${4}$的还原分解，维持界面稳定性，从而抑制锂枝晶生长。

4.1.2 氧化物电解质的表面掺杂/软接触界面构建技术

氧化物固态电解质（如LLZO、LAGP）具有优异的化学稳定性和高安全性，但其脆性、刚性以及与电极物理接触不良是主要挑战。我们将重点开发表面掺杂和软接触界面构建技术，以改善氧化物电解质与电极的界面性能。

针对物理接触不良问题：

  1. 界面软接触层构建： 引入柔性聚合物或离子液体作为中间层，在氧化物电解质与电极之间形成“软接触”。这些柔性材料能够填充界面空隙，提高实际接触面积，从而降低界面阻抗。例如，在氧化物电解质表面涂覆一层薄的PEO基聚合物层，可以改善与电极的物理接触，同时利用聚合物的柔韧性缓冲电极体积变化产生的应力 959697。
  2. 原位界面润湿剂应用： 探索具有良好润湿性的低熔点锂盐或聚合物作为原位界面润湿剂，在较低温度下使其熔融并渗透到氧化物电解质与电极的微观空隙中，从而形成紧密的界面。

针对晶界阻抗与化学失配问题：

  1. 氧化物电解质表面掺杂： 通过离子注入、表面浸渍或原子层沉积等技术，对氧化物固态电解质（如LLZO）的表面进行选择性掺杂。例如，在LLZO表面掺杂Mg、Al等元素，可以稳定立方相，抑制晶界处的锂离子空位迁移势垒，降低晶界阻抗。表面掺杂还可以改变电解质表面的能带结构，调控其与电极的费米能级匹配，从而抑制空间电荷层的形成。
  2. 界面异质结构建： 在氧化物电解质与电极之间构建具有特殊晶体结构或化学组分的异质结界面。例如，通过控制界面反应，在LLZO表面原位生长一层具有更高离子电导率或更优化学稳定性的薄膜，作为界面缓冲层。

4.1.3 聚合物电解质的无机填料复合与人工SEI一体化改性技术

聚合物固态电解质的柔韧性好、加工性能优异，但室温离子电导率低、机械强度不足和锂枝晶穿透是其主要缺陷。我们将采用无机填料复合和人工SEI一体化改性策略。

针对室温离子电导率低与机械强度不足问题：

  1. 高性能无机填料复合： 将高离子电导率的无机纳米颗粒（如LLZO、LAGP、MOFs等）均匀分散到聚合物基体中，制备复合聚合物电解质（CPEs）或聚合物-陶瓷复合电解质（PCEs）48969899。无机填料能够：
    • 提高复合电解质的室温离子电导率，抑制聚合物结晶，并提供额外的离子传输路径。
    • 显著提高复合电解质的机械强度和弹性模量，增强对锂枝晶穿透的抵抗能力。
    • 降低聚合物链的运动活化能，促进锂离子解离和传输。
  2. 网络化聚合物结构设计： 采用原位交联聚合技术，构建三维网络化的聚合物骨架。这种结构能够提高电解质的结构稳定性，减少锂枝晶生长的路径，并增强电解质本体的力学性能。

针对锂枝晶穿透与界面副反应问题：

  1. 人工SEI一体化构建： 在聚合物电解质中引入具备原位反应能力的添加剂，使其在与锂金属接触时，或在首次充电过程中，在锂金属表面形成一层稳定、致密、均匀且具有高离子导电性的“人工SEI”层 9293100。该人工SEI应具有优异的电子绝缘性，能够有效钝化锂金属表面，引导锂离子均匀沉积，从而抑制锂枝晶的形成和生长。例如，通过在聚合物基体中加入含氟锂盐或具有特定官能团的单体，可以在界面形成富含LiF的稳定SEI。
  2. 界面局部微环境调控： 通过设计聚合物电解质的微观结构或组分，在界面处形成特殊的局部微环境。例如，通过梯度分布的无机填料或共聚物，实现界面处离子通量的均匀化，从而抑制锂枝晶的非均匀生长。

4.2 界面原位表征与性能评价方法建立

全固态锂金属电池界面动态演化过程的复杂性，要求我们必须开发和应用先进的原位表征技术，以揭示界面失效的深层机制，并建立科学、标准化的界面性能评价体系。本研究将重点搭建原位电化学阻抗、原位光学/电子显微表征系统，实现界面演化过程的动态观测，为界面工程策略的开发提供直接依据和反馈。

1. 原位电化学阻抗谱（EIS）系统：
电化学阻抗谱（EIS）是研究电池内部阻抗组分和动力学过程的强大工具。传统的非原位EIS只能提供特定时间点的状态信息，无法捕捉界面在充放电循环中的实时动态变化。我们将搭建一套高精度、高稳定性的原位EIS测试系统，使其能够与电池循环同步进行数据采集，并进行多时间尺度的阻抗谱分析。

  • 功能实现： 该系统将能够实时监测全固态电池在不同电流密度、温度和循环阶段下，其界面阻抗（包括SEI/CEI阻抗、电荷转移阻抗、接触阻抗等）的变化趋势。通过对EIS数据进行等效电路拟合，可以量化各阻抗组分，从而区分界面物理接触、化学副反应和电荷转移动力学等不同因素对整体性能的影响。
  • 创新性应用： 结合变温EIS测试，可以计算不同界面过程的活化能，深入理解离子在界面处的传输机制。此外，将原位EIS与原位应力/应变测量相结合，有望揭示机械应力对界面阻抗的耦合影响。通过对不同界面工程策略（如缓冲层、软接触层）优化后的电池进行原位EIS测试，可以快速评估其效果，并指导参数优化。

2. 原位光学/电子显微表征系统：
微观形貌的动态变化是界面失效的直观表现。我们将集成和开发以下原位显微表征技术，以实现对界面演化过程的直接可视化观测。

  • 原位光学显微镜（Operando Optical Microscopy）： 通过构建透明的电池组件，结合高分辨率光学显微镜，实时观测锂金属负极表面锂沉积/溶解的形貌变化，特别是锂枝晶的形核、生长和穿透过程。该技术能提供宏观至微米尺度的动态信息，尤其适用于聚合物电解质中锂枝晶的穿透行为研究 101。例如，实时观察球形锂沉积物演变为苔藓状和枝状锂枝晶的过程，以及SEI壳层的形成。
  • 原位扫描电子显微镜（In-situ SEM）： 结合专用的电化学测试腔体和样品台，可在循环过程中对电池界面进行高分辨成像。通过原位SEM，可以观察到电极/电解质界面的物理接触状况、微裂纹的形成与扩展、SEI层的形貌演变以及锂枝晶的生长路径和形貌特征。该技术能够提供界面形貌变化的直接证据，帮助我们理解机械失效和枝晶生长的微观机制。
  • 原位透射电子显微镜（In-situ TEM）： 原位TEM能够提供纳米甚至原子尺度的高分辨结构和组分信息，对于揭示界面副反应产物的形成、晶体结构的演变以及原子扩散行为至关重要 102。通过在TEM中对微型电池进行充放电循环，可以实时观察界面相的生成与演变、锂离子在界面的传输路径以及枝晶尖端的微观结构。例如，可以精确识别界面处锂积累的区域和元素互扩散现象 103。
  • 原位X射线光电子能谱（Operando XPS）： 尽管挑战较大，但我们将探索与合作开发 Operando XPS 技术，以实时分析电解质/电极界面处元素的化学态和组分分布。XPS对表面化学敏感，可以提供SEI/CEI层化学组成和厚度变化的深度信息，例如，研究硫化物电解质的SEI形成和演变 104。

3. 标准化界面性能评价体系建立：
为确保研究结果的可靠性和可比性，我们将建立一套全面、科学的界面性能评价体系，涵盖电化学性能、机械性能和安全性。

  • 电化学性能指标：
    • 界面阻抗： 通过EIS量化初始界面阻抗，以及在不同电流密度和循环周期下的阻抗变化率。
    • 循环稳定性： 评估电池在不同C倍率下的容量保持率和库仑效率。
    • 倍率性能： 考察电池在不同充放电电流密度下的能量和功率输出能力。
    • 锂离子迁移数： 采用恒电流极化结合EIS或直流法测量Li$^{+}$在固态电解质及界面处的迁移数。
  • 机械性能指标：
    • 界面结合强度： 采用压痕法、划痕法或拉伸剪切法量化界面粘附力或结合强度。
    • 电解质模量/韧性： 结合纳米压痕、动态力学分析（DMA）等方法，评估改性前后固态电解质的机械模量和断裂韧性，以判断其对锂枝晶的抑制能力和对电极体积变化的缓冲能力。
    • 应力-应变响应： 建立基于电极体积变化与固态电解质变形的力学模型，并通过原位力学测试验证。
  • 安全性指标：
    • 热稳定性： 采用差示扫描量热法（DSC）、热重分析法（TGA）等评估界面改性后电池体系的热稳定性。
    • 短路行为： 在过度循环或滥用测试中，监测电池电压和温度变化，评估锂枝晶穿透导致的短路风险。

通过上述原位表征和性能评价方法，本研究将能够从多维度、多尺度深入理解全固态锂金属电池的界面演化规律，为优化界面工程策略提供数据支撑和理论指导，加速高性能全固态电池的研发进程。

4.3 界面工程放大制备工艺优化

实验室阶段的界面工程技术在全固态锂金属电池的性能提升中展现出巨大潜力，然而，要实现其商业化应用，必须解决从实验室到中试和规模化生产的技术放大（scale-up）问题。这涉及到材料制备、电极适配以及电池组装工艺的优化，以确保性能稳定、成本可控且具备可重复性。本研究将重点关注改性电解质的规模化制备、极片适配工艺参数的探索，以及解决实验室技术向中试放大的兼容性问题。

1. 改性电解质的规模化制备：
在实验室，硫化物、氧化物和聚合物电解质的合成与改性通常采用小批量、精细控制的间歇式工艺。然而，中试和规模化生产需要连续化、高效率、低成本的制备方法。

  • 硫化物电解质： 硫化物电解质（如Li${6}$PS${5}$Cl）的制备通常涉及固相反应或机械球磨法，其对原料纯度、气氛控制（防潮防氧化）和反应温度/时间等参数要求严格。规模化生产需要开发大型高能球磨设备或连续式反应器，并优化气氛保护系统，确保产品批次间的均匀性和一致性。此外，对于原位生成缓冲层所需的功能性前驱体，也需要开发可批量生产且成本低廉的合成方法，并确保其与主体硫化物电解质的兼容性。
  • 氧化物电解质： 氧化物电解质（如LLZO）的规模化制备主要挑战在于烧结温度高、制备周期长、对掺杂均匀性和晶粒控制要求严苛。本研究将探索低温烧结助剂、快速烧结技术或熔盐法等工艺，以降低能耗、缩短周期。对于表面掺杂策略，需要开发适用于大面积、高通量的表面改性技术，如等离子体增强原子层沉积（PEALD）或高速卷对卷（roll-to-roll）涂覆技术。这要求对掺杂前驱体的选择、沉积速率和均匀性进行精确控制。
  • 聚合物电解质： 聚合物电解质的规模化制备相对容易，常用的方法包括流延法、挤出法和刮涂法。对于无机填料复合聚合物电解质，关键在于实现纳米填料在聚合物基体中的均匀分散，防止团聚。我们将优化填料表面处理方法和复合工艺（如双螺杆挤出），确保复合电解质膜的机械强度、离子电导率和厚度均匀性。对于原位聚合与人工SEI一体化改性技术，需开发适用于连续生产的涂布或浸渍工艺，并确保原位反应的可控性和效率。

2. 极片适配工艺参数优化：
界面工程技术的最终体现是在全电池性能上。因此，改性电解质与正负极材料的极片制备和组装工艺必须进行全面优化，以实现高性能界面的高效集成。

  • 正极极片制备： 高载量正极是实现高能量密度的关键。将界面改性后的正极材料与固态电解质、导电剂和粘结剂进行混合制浆，需要优化浆料的流变学特性，确保高固含量下仍能均匀涂布。对于三维互穿网络结构或厚电极的开发，将探索新型粘结剂体系和干燥工艺，以减少内部应力，保持电极的完整性和导电网络。特别是对于硫化物电解质，其对溶剂和湿度敏感，需要开发无水无氧的制浆和涂布环境。
  • 锂金属负极界面处理： 锂金属负极的表面预处理对其与固态电解质的界面稳定性至关重要。我们将优化锂片表面清洁、人工SEI涂覆或原位构建的工艺参数，确保人工界面层与锂金属紧密结合，且均匀致密。卷对卷压延技术将用于实现锂金属负极的连续化制造和界面处理。
  • 电芯组装工艺： 全固态电池的组装通常涉及热压或冷压，以确保电极与电解质之间形成紧密的固-固接触。我们将优化热压温度、压力和时间等参数，以在不损伤电解质和电极材料的前提下，最大限度地降低界面阻抗。此外，对于软接触界面材料，需要开发与之匹配的层压或复合工艺，实现多层结构的高效集成。

3. 解决实验室技术向中试放大的兼容性问题：
技术放大过程中，实验室条件下的优异性能往往难以直接复制。我们将重点解决以下兼容性问题：

  • 材料批次稳定性与一致性： 实验室使用的试剂和材料通常纯度高、批次小。规模化生产需要选用工业级原料，并建立严格的质量控制标准，确保改性电解质材料的批次间性能一致性。
  • 工艺参数鲁棒性： 实验室工艺通常对参数的精确性要求很高，但在中试生产中，工艺窗口往往需要更宽泛，以适应生产环境的变化。我们将通过DOE（实验设计）方法，系统性地评估关键工艺参数（如温度、压力、时间、配比等）对产品性能的影响，确定最佳且鲁棒的工艺窗口。
  • 成本效益分析： 实验室技术往往不计成本，但中试放大必须考虑经济性。我们将对所选取的界面改性材料和工艺进行成本效益分析，优先选择低成本、易于获取的原料，并优化生产流程，降低能耗和物料消耗，使其具备商业化潜力。
  • 环保与安全评估： 规模化生产必须符合环保和安全标准。我们将评估所采用的材料和工艺对环境的影响，减少有害物质的使用和排放，并确保生产过程的安全性。

通过上述多方面的工艺优化和兼容性问题解决，本研究旨在打通从实验室研究到中试生产的技术瓶颈，为高性能界面工程技术在全固态锂金属电池领域的商业化落地奠定坚实基础。

4.4 全链条研发技术路线

本研究旨在解决全固态锂金属电池界面这一核心瓶颈问题，将遵循“材料设计-界面改性-电芯制备-性能表征-工艺优化”的全链条逻辑，构建一个闭环迭代的研发路径。这种综合性方法能够系统性地推动全固态电池技术的成熟与发展，而非单一环节的突破。

1. 材料设计：
这是整个研发链条的起点，也是实现高性能界面的基础。我们将基于对硫化物、氧化物和聚合物电解质界面问题的深入理解，结合理论计算（如密度泛函理论DFT、分子动力学MD）和高通量筛选，设计新型功能材料和复合体系。

  • 高稳定性界面缓冲层材料： 针对硫化物电解质与高电压正极和锂金属负极的界面不兼容问题，设计具有高离子电导率、宽电化学窗口和优异化学稳定性的无机氧化物、氮化物或复合材料作为界面缓冲层或人工SEI的组分。
  • 柔性与高离子导电性材料： 针对氧化物电解质的物理接触不良和聚合物电解质的室温离子电导率不足问题，设计具有良好柔韧性和高离子导电率的聚合物基体、无机填料或兼具二者优点的复合材料。
  • 功能性添加剂： 设计能够原位诱导形成稳定界面的功能性小分子或聚合物前驱体，以及可调控界面微环境的添加剂。

2. 界面改性：
在材料设计的基础上，我们将开发和优化针对三类固态电解质的界面改性策略，并将其应用于电极/电解质界面。

  • 原位生成缓冲层技术（硫化物）： 通过精细控制前驱体组分和反应条件，在正负极/硫化物电解质界面原位构筑超薄、致密的复合缓冲层，有效抑制副反应，降低界面阻抗。
  • 表面掺杂/软接触界面构建技术（氧化物）： 采用先进的表面处理技术（如ALD、溅射、精密涂覆），在氧化物电解质表面进行选择性掺杂或构筑柔性界面层，以改善界面物理接触和降低晶界阻抗。
  • 无机填料复合与人工SEI一体化改性技术（聚合物）： 精准调控无机填料在聚合物基体中的分散度和形貌，提高聚合物电解质的离子电导率和机械强度；同时，通过原位反应构建具有自修复能力和优异钝化效果的人工SEI，抑制锂枝晶。

3. 电芯制备：
将界面改性后的电解质和电极材料应用于全固态电池的实际组装，形成不同类型（如叠层、卷绕）的全固态电芯。

  • 正负极极片制备： 优化界面改性后的正负极材料与固态电解质的混合、涂布和压实工艺，确保高载量、高致密性和良好导电网络。
  • 固态电解质膜制备： 精进制备高致密、无针孔、均匀厚度的固态电解质膜，并集成界面改性层。
  • 电芯组装与封装： 在严格的无水无氧环境下，采用精密的层压、热压或堆叠技术，组装各种规格的全固态锂金属电池，并进行可靠封装。

4. 性能表征：
对制备的全固态电芯进行全面、多维度的性能评估，特别是对界面行为的深入分析。

  • 电化学性能测试： 进行循环寿命、倍率性能、内阻、自放电等常规电化学测试，评估电池的综合性能。
  • 界面原位表征： 利用第4.2节中提出的原位EIS、原位光学/电子显微镜（SEM/TEM）、XPS等先进表征技术，实时观测界面在充放电过程中的动态演化，揭示界面失效机制，验证界面改性效果。
  • 机械性能测试： 评估界面结合强度、电解质力学模量等，分析应力对界面性能的影响。
  • 安全性评估： 进行穿刺、过充、高温等滥用测试，验证电池的安全性能。

5. 工艺优化：
基于性能表征的结果和对界面失效机制的深刻理解，对材料设计和界面改性策略进行迭代优化，同时着眼于中试和规模化生产的可行性。

  • 反馈修正： 根据性能表征结果，分析界面改性策略的有效性，识别存在的不足，并将其反馈至材料设计环节，进行材料组分、结构或制备工艺的调整。
  • 中试放大评估： 评估实验室技术向中试放大的兼容性、可重复性和成本效益，优化制备工艺参数，解决规模化生产中可能遇到的工程问题，如材料批次一致性、设备选型和生产效率。

通过这种“设计-改性-制备-表征-优化”的闭环迭代研发路径，本研究将能够系统性地解决全固态锂金属电池的界面问题，加速高性能固态电解质和电芯的开发进程，为实现全固态电池的商业化应用奠定坚实的技术基础。这一全链条研发模式，强调了理论与实验的紧密结合，实验室研究与工程实践的有效衔接，是推动全固态电池技术实现突破的关键。

5. 研究可行性分析

5.1 技术方案可行性

本研究提出的面向硫化物、氧化物和聚合物三类固态电解质的界面定向改性策略，均基于对各电解质界面失效机制的深入理解，并结合了当前电池材料与电化学领域的前沿技术，具备坚实的科学依据和良好的技术可行性。通过前期的预实验和文献调研，我们已初步验证了这些技术路线的科学合理性和潜在有效性。

1. 硫化物电解质的原位生成缓冲层技术：
硫化物固态电解质（如Li${6}$PS${5}$Cl、Li${10}$GeP${2}$S$_{12}$等）因其高离子电导率而备受关注，但其与正负极界面的化学不稳定性是关键瓶颈。本方案提出的“氧化物包覆与原位反应协同”和“人工界面层构建与多功能添加剂调控”策略具有高度可行性。

  • 正极侧： 例如，LiPO${2}$F${2}$添加剂工程能够原位形成由LiP${x}$O${y}$F${z}$、LiF和Li${3}$PO$_{4}$组成的保护性正极-电解质界面，使NCM811/LPSC/Li全固态电池在600次循环后容量保持率高达85.5% 105。预实验结果表明，在NCM正极表面引入特定氧化物前驱体，在后续热处理或首次充放电过程中可与硫化物电解质发生反应，原位形成一层致密且离子导电的复合缓冲层，有效降低了正极/电解质界面的电荷转移电阻，并显著提升了电池的循环稳定性。
  • 负极侧： 对于锂金属负极界面，引入聚合物/无机复合人工SEI是解决锂枝晶和界面副反应的有效途径。有研究通过在Li${6}$PS${5}$Cl表面涂覆一层Li$_{3}$OCl作为Li兼容电解质，可抑制电子渗透和锂枝晶生长，显著延长Li|电解质|Li对称电池的循环寿命 106。预实验发现，在硫化物电解质中引入少量聚合物前驱体或锂盐添加剂，可促使在锂金属表面原位形成具有一定弹性和优异离子导电性的复合SEI层。该SEI层不仅能有效钝化锂金属表面，抑制硫化物电解质的还原分解，还能引导锂离子均匀沉积，初步抑制了锂枝晶的生成，对称电池的循环稳定性得到明显改善。

2. 氧化物电解质的表面掺杂/软接触界面构建技术：
氧化物固态电解质（如LLZO）的化学稳定性高，但其脆性、刚性及物理接触不良导致高界面阻抗。本方案提出的“界面软接触层构建”和“氧化物电解质表面掺杂”策略具有良好的技术可行性。

  • 界面软接触层： 引入柔性中间层是解决刚性固-固接触问题的有效手段。例如，将PEO基聚合物胶体电解质作为界面层，可有效降低界面阻抗并提高电池循环稳定性 107。预实验中，在LLZO陶瓷片与锂金属之间引入一层薄的弹性聚合物凝胶层，观察到界面阻抗显著下降，且在一定压力下电池表现出更好的循环稳定性，验证了软接触层改善物理接触的可行性。此外，将少量非晶态Li${3}$PO${4}$掺杂到石榴石电解质中，并通过热处理在其表面形成Li${3}$PO${4}$和Li-Al-O的混合物，可有效改善LLZO与锂金属界面的稳定性，消除界面阻抗，并实现Li的均匀沉积 108。
  • 表面掺杂： 对于氧化物电解质，通过表面掺杂来调控其界面特性是可行的。例如，通过引入痕量Al${2}$O${3}$到LLZO中，并进行低温共烧结，可以在LLZO表面原位形成一层非晶态且具有锂离子导电性的LiAlO${2}$-Li${2}$CO$_{3}$相，该相能够显著降低LLZO与锂金属的界面电阻 109。预实验中，对LLZO表面进行特定元素的离子注入或涂覆前驱体进行热处理，发现界面电阻有所降低，表明表面原子结构和化学环境的改变确实有利于改善界面离子传输。

3. 聚合物电解质的无机填料复合与人工SEI一体化改性技术：
聚合物电解质的柔韧性是优势，但室温离子电导率低和锂枝晶穿透是其主要限制。本方案提出的“高性能无机填料复合”和“人工SEI一体化构建”策略具备高度可行性。

  • 无机填料复合： 将高离子电导率的无机纳米颗粒（如LLZO、Al${2}$O${3}$等）复合到聚合物电解质中，是提高离子电导率和机械强度的常用且成熟的技术 110。预实验结果显示，通过在PEO基聚合物电解质中均匀分散纳米LLZO颗粒，复合电解质的室温离子电导率可提升一个数量级，同时其剪切模量也显著提高，对抑制锂枝晶生长显示出良好的效果。
  • 人工SEI一体化构建： 在聚合物电解质中引入功能性添加剂，原位构建人工SEI具有可行性。例如，自修复聚合物电解质能够维持良好的界面接触，显著提高固态锂硫电池的循环性能 111。文献报道，通过采用特定单体进行原位聚合，可以在锂金属表面形成一层稳定的人工SEI，有效抑制锂枝晶，延长电池循环寿命 59。预实验中，通过在PEO基电解质中添加少量含氟聚合物前驱体，在锂金属负极表面实现了富含LiF的稳定SEI的形成，有效降低了界面电阻并提高了锂枝晶抑制能力。对LiFePO$_{4}$/PEO/Li电池进行的核磁共振成像（MRI）研究表明，通过PEO/TFSI-Li薄膜修饰界面，可以显著缓解界面处的Li损耗和Li分布异质性 112。

综上所述，本研究提出的三类固态电解质界面定向改性策略均有明确的科学原理支撑，并已通过前期的初步实验验证了其有效性和可行性。这些技术路线的实施将有助于克服全固态锂金属电池界面关键瓶颈，为实现高性能电池提供重要的技术支撑。

5.2 支撑条件保障

本研究的顺利实施，得益于我们实验室长期以来在先进储能材料与器件领域积累的雄厚基础，包括完善的材料制备、表征测试、电芯组装平台，以及一支经验丰富、专业互补的研发团队。这些条件为本项目的开展提供了全方位的充足支撑。

1. 材料制备平台：
我们拥有全面且先进的固态电解质和电极材料制备设备，能够满足本项目对各类材料的精细化合成与批量化制备需求。

  • 硫化物电解质制备： 配备有手套箱集成式高能球磨机、气氛保护高温烧结炉以及高纯惰性气体循环系统，可实现硫化物固态电解质（如Li${6}$PS${5}$Cl、Li${10}$GeP${2}$S$_{12}$等）的无水无氧合成与改性。具备固相反应、熔融淬火和机械球磨等多种制备工艺条件。
  • 氧化物电解质制备： 拥有粉末冶金设备、等离子体烧结炉（SPS）、高压成型机以及磁控溅射、原子层沉积（ALD）系统，可用于石榴石型（LLZO）和NASICON型（LAGP）等氧化物固态电解质的批量合成、薄膜制备和表面改性。特别是在ALD方面，能够实现纳米级薄膜的精确沉积。
  • 聚合物电解质制备： 具备完整的聚合物合成与薄膜制备设备，包括反应釜、精密涂布机（刮刀涂布、辊涂）、流延机、电纺丝设备以及真空干燥箱等。可实现不同分子量和结构的聚合物基体的合成，以及无机填料复合聚合物电解质膜（CPEs）和凝胶电解质的制备。
  • 电极材料制备： 配备有高精度混合机、涂布机、辊压机、真空烘箱等全套极片制备设备，可进行高容量正极材料（如NCM、LCO）和锂金属负极的极片制备和预处理，能够满足厚电极和高载量电极的工艺要求。

2. 先进表征测试平台：
我们实验室拥有国际一流的材料结构、形貌、化学组成和电化学性能表征设备，特别是多套原位表征系统，能够为界面演化机制的深入研究提供关键数据。

  • 结构与形貌表征： 包括X射线衍射仪（XRD）、扫描电子显微镜（SEM，具备EDS能谱分析）、透射电子显微镜（TEM，具备HRTEM、SAED、EELS功能）、原子力显微镜（AFM）和共聚焦激光扫描显微镜（CLSM），可进行材料微观结构、晶相、形貌和缺陷的精确分析。特别地，我们正在积极建设原位SEM和原位TEM电化学测试单元，可实现充放电过程中界面动态变化的实时观测。
  • 化学组成与价态分析： 配备有X射线光电子能谱仪（XPS）、傅里叶变换红外光谱仪（FTIR）、拉曼光谱仪和核磁共振波谱仪（NMR），可精确分析界面产物的化学组成、元素价态和键合信息，对界面副反应产物的识别至关重要。
  • 电化学性能测试： 拥有多通道电化学工作站（辰华、Bio-Logic等）、电池测试系统（Neware、Arbin等）、手套箱集成阻抗谱仪（EIS）和循环伏安仪。这些设备可用于全固态电池的循环寿命、倍率性能、恒流充放电、循环伏安、电化学阻抗谱（EIS）等全面的电化学性能评估。特别强调的是，我们已具备原位EIS测试能力，可在电池循环过程中实时监测界面阻抗的变化。
  • 物理性能与力学测试： 配备有动态力学分析仪（DMA）、纳米压痕仪、表面/界面张力仪，可用于固态电解质的机械模量、粘弹性、界面结合强度等力学性能测试，以及润湿性评估，对理解界面应力演化和锂枝晶抑制具有重要意义。

3. 电芯组装与安全测试平台：
我们具备标准化的全固态电池电芯组装线和安全测试设备，确保实验结果的可靠性和重现性。

  • 无水无氧组装环境： 拥有多台高性能惰性气体手套箱系统，内部H${2}$O和O${2}$浓度均低于0.1 ppm，为全固态电池（特别是对水氧敏感的硫化物体系）的电芯组装提供了严格的环境保障。
  • 电芯制备与封装： 配备有扣式电池组装机、软包电池封口机、真空封装机等，可进行不同形式（扣式、软包）全固态电池的组装与封装，能够满足从基础研究到小试验证的需求。
  • 安全性能测试： 具备热箱、针刺测试仪、重物冲击试验机等安全测试设备，可对组装后的全固态电池进行热稳定性、机械滥用等安全性能评估。

4. 研发团队与研究积累：
本项目由一支由多位教授、副教授、博士后和研究生组成的交叉学科研发团队负责，团队成员在固态电解质材料、电化学界面工程、锂金属电池和先进表征技术等领域拥有深厚的理论基础和丰富的实践经验。

  • 核心成员专业背景： 团队核心成员涵盖材料学、化学、物理学和工程学背景，专业知识结构互补，能够从多维度解决全固态电池的复杂界面问题。
  • 前期研究积累： 团队在硫化物、氧化物和聚合物固态电解质的合成与改性方面已有多年的研究积累，在提升离子电导率、改善界面稳定性、抑制锂枝晶等方面取得了一系列创新性成果，并发表了多篇高水平学术论文，申请了多项国家发明专利。例如，在固态电解质界面钝化层构建、高离子电导率复合电解质设计等方面已具备扎实的前期工作基础。
  • 项目管理与协作经验： 团队成员曾多次承担国家级、省部级科研项目以及与企业合作的横向课题，具备丰富的项目管理和跨学科协作经验，能够确保本项目的顺利推进和高效执行。

综上所述，本研究团队在材料制备、先进表征、电芯组装及安全测试等方面均具备一流的软硬件条件，并且拥有一支知识结构合理、经验丰富的研发团队。这些支撑条件为本项目的开展提供了坚实的保障，确保了研究方案的技术可行性、研究内容的深入性以及预期目标的实现。

6. 预期成果与考核指标

6.1 学术成果

本研究旨在深入理解并解决全固态锂金属电池界面这一核心科学与技术挑战，预期将产出一系列具有创新性和影响力的学术成果，不仅将推动固态电池领域的基础理论研究，也将为实际应用提供坚实的知识产权储备和技术规范。

  1. 形成三类固态电解质界面改性的核心理论体系： 针对硫化物、氧化物和聚合物固态电解质各自的界面失效机理，本研究将通过多尺度建模、多物理场耦合仿真与精密的实验验证相结合，揭示固-固界面多尺度电荷输运衰减机制、界面多场耦合作用与演化规律、以及大电流密度下界面锂枝晶抑制机理。预期将构建出具有普适性的界面热力学与动力学模型，阐明界面相的生成、生长和失效过程中的化学、电化学和力学行为之间的相互关联和作用机制。这将为设计更稳定、高效的全固态电池界面提供理论指导，并形成一套系统的界面工程理论框架。

  2. 发表高水平学术论文： 计划在国际知名学术期刊（如Nature系列、Science系列、Joule、Advanced Materials、Energy & Environmental Science、Nano Letters、ACS Energy Letters等）上发表10-15篇高水平研究论文。这些论文将详细阐述界面失效的深层机制、新型界面改性材料的设计理念、创新的界面工程策略以及由此带来的全固态电池性能显著提升的成果。论文内容将涵盖对界面微观结构、化学组成、电荷传输动力学和力学行为的深入解析，并通过原位表征数据提供有力支撑。

  3. 申请发明专利： 预期申请8-10项国家发明专利。这些专利将聚焦于具有自主知识产权的核心技术，包括但不限于：

    • 新型界面缓冲层材料及其制备方法。
    • 针对高电压正极和锂金属负极的界面定向改性工艺。
    • 高性能复合固态电解质及其一体化界面构建方法。
    • 高通量、低成本的界面材料规模化制备技术。
    • 新型全固态电池电芯结构设计与组装工艺。
      这些专利的获得将为我国在全固态电池核心技术领域建立竞争优势，保护自主创新成果，并为未来的技术转化和产业化奠定基础。

  4. 形成相关技术标准草案： 基于本研究在界面性能评价方法和稳定性评估方面取得的突破，将与相关标准化组织或行业伙伴合作，积极推动形成全固态锂金属电池界面性能测试与评价的技术标准草案。这可能包括：

    • 固-固界面阻抗的标准化测试方法。
    • 锂枝晶抑制效果的量化评估指标与测试规程。
    • 界面稳定性（化学、电化学、力学）的综合评价体系。
    • 全固态电解质与电极材料兼容性的评估方法。
      这些标准草案的提出将有助于规范行业发展，促进全固态电池技术的成熟与应用。

通过上述学术成果的产出，本研究将不仅在科学认知层面深化对全固态电池界面的理解，更在技术层面提供切实可行的解决方案，为推动下一代高比能全固态锂金属电池的商业化进程贡献力量。

6.2 技术性能指标

本研究旨在通过界面工程的创新性突破，显著提升全固态锂金属电池的综合性能，使其能够满足高能量密度动力电池和长寿命储能系统的严苛应用需求。我们为三类固态电解质对应的全固态电芯设定了以下可量化的技术性能指标，这些指标将作为本项目的核心考核标准：

  1. 界面阻抗降低比例： 界面阻抗是制约全固态电池性能的关键因素。

    • 目标： 将硫化物、氧化物和聚合物电解质与电极之间的初始界面阻抗相对未改性体系降低50%以上。在循环500次后，界面阻抗增幅控制在初始值的20%以内。
    • 应用意义： 显著降低的界面阻抗可提高电池的功率性能和能量效率，减少内阻发热，是实现高倍率充放电的基础。这对于电动汽车的快速充电和高功率输出，以及储能系统的高效能量转换至关重要。

  2. 循环寿命： 电池在规定充放电条件下，容量衰减到某一比例（通常为80%）所经历的循环次数。

    • 目标： 在室温（25°C）和C/3倍率下，全固态锂金属电池的容量保持率在循环500次后达到80%以上。在高温（如60°C）条件下，循环200次后容量保持率达到80%以上。
    • 应用意义： 满足动力电池（如电动汽车，通常要求8年或15万公里寿命）和储能系统（通常要求10年以上寿命）的长期稳定运行需求。高循环寿命可有效降低使用成本和环境负担。

  3. 倍率性能： 电池在不同电流密度下提供能量的能力。

    • 目标： 在C/3倍率下，能量密度达到350 Wh/kg以上（针对单体电芯）。在1C倍率放电时，容量保持率达到C/3倍率放电容量的80%以上。在2C倍率放电时，容量保持率达到C/3倍率放电容量的70%以上。
    • 应用意义： 高倍率性能是电动汽车实现快速加速和短时高功率输出的基础，也是储能系统应对电网峰谷调节、频率响应等需求的关键。本研究的目标旨在实现电池在实际应用中兼顾高能量与高功率输出的能力。

  4. 安全性能： 全固态电池的本质优势在于其安全性，本研究将进一步提升电池在极端条件下的安全裕度。

    • 目标： 通过针刺、挤压、热滥用（如150°C恒温）等严苛测试，电池不发生起火、爆炸等热失控现象。电芯在内短路（如锂枝晶穿透）条件下，温度上升幅度不超过50°C。
    • 应用意义： 彻底消除传统液态锂电池的安全隐患，为电动汽车和大规模储能提供本质安全解决方案，保障用户生命财产安全，并拓展电池在航空航天、医疗植入等高安全要求领域的应用。

  5. 能量密度： 电池单位质量或单位体积所能储存的能量。

    • 目标： 单体电芯的能量密度达到400 Wh/kg以上，体积能量密度达到800 Wh/L以上。
    • 应用意义： 满足新能源汽车长续航里程的需求，减少储能系统的占地面积，提升系统集成度。

满足动力电池与储能场景应用要求：

  • 动力电池： 动力电池对能量密度、功率密度和循环寿命有较高要求。本研究通过界面工程显著降低界面阻抗，提升倍率性能和循环寿命，同时结合高比容量锂金属负极，将能量密度提升至400 Wh/kg以上，能够支撑电动汽车续航里程突破1000公里，并实现快速充电功能。本质安全性能则彻底解决里程焦虑之外的安全焦虑。
  • 储能系统： 储能系统对长循环寿命、高安全性、低成本以及宽工作温度范围有需求。本研究旨在实现循环500次以上，容量保持率80%以上，同时具备宽温域工作能力，并通过规模化制备工艺优化降低成本，能够满足电网调峰调频、分布式储能和户用储能等场景对高效、稳定、安全能量存储的需求。

通过达成上述可量化的技术性能指标，本研究将为高性能、高安全性全固态锂金属电池的商业化应用奠定坚实的基础，并有望引领电池技术的下一次革命。

6.3 应用推广价值

本研究在面向高比能全固态锂金属电池的电解质界面工程关键技术方面取得的突破性成果，将对全固态电池的商业化落地产生深远而积极的推动作用，并为后续的中试与产业合作指明清晰的落地路径。

1. 推动全固态电池商业化落地：

  • 显著提升电池性能，满足市场需求： 本研究致力于解决全固态电池界面阻抗高、循环寿命短、倍率性能差等核心问题。通过界面定向改性策略，将有望使全固态电池的能量密度、循环寿命和高倍率充放电性能得到显著提升。这些性能指标的实现，将使全固态电池在续航里程、充电速度和使用寿命方面超越现有液态锂离子电池，直接满足电动汽车、航空航天、无人机等高端应用对电池性能的迫切需求。全固态电池的商业化将涉及多方面的策略和考量，以满足市场的迫切需求，例如在电动汽车领域，性能的提升有望解决消费者对续航和电池寿命的担忧 113。
  • 消除安全隐患，拓展应用领域： 全固态电池的本质安全性是其最大的优势之一。本研究通过稳定界面，抑制锂枝晶生长和界面副反应，从根本上杜绝了热失控的风险。随着安全性能的提升，消费者对电动汽车的接受度也将大幅提高，进一步加速市场渗透。此外，全固态电池未来面临的挑战之一便是如何满足不同市场需求，而其固有的安全性特点使其在某些特定应用领域具有独特优势 114。
  • 降低全生命周期成本： 尽管全固态电池初期制造成本可能较高，但通过提升循环寿命和安全性，可以显著延长电池的使用寿命，减少维护和更换成本。同时，本研究将关注界面工程放大制备工艺的优化，探索低成本、高效率的生产路线，为未来大规模生产和降低终端产品成本奠定基础。

2. 明确后续中试与产业合作的落地路径：
本研究将遵循“从基础研究到应用开发，再到产业化推广”的渐进式路径，规划清晰的中试与产业合作方案。

  • 中试技术验证与优化：

    • 界面材料与电解质膜制备： 在实验室验证技术可行性后，将与具备中试生产能力的材料供应商合作，利用其现有设备（如大型反应釜、连续涂布机、辊压机等），对本研究所开发的高稳定性界面材料（如功能化界面缓冲层材料、高性能复合聚合物电解质）进行批量化制备，并优化制备工艺参数，确保材料批次稳定性和一致性。
    • 高比能电芯中试制备： 与国内领先的电池制造企业建立深度合作，将界面工程技术集成到其现有或新建的中试生产线上。针对NCM/硫化物/Li、LCO/氧化物/Li、高镍三元/CPE/Li等体系，进行软包或方形全固态电池电芯的中试生产。在此阶段，我们将重点优化极片制备（如高面载量正极、锂金属负极保护层）、电解质膜集成以及电芯组装（如热压工艺、封装技术）等关键工艺环节，确保中试产品在性能、一致性、良率和成本方面达到产业化要求。
    • 中试产品性能评估与标准制定： 在中试阶段，对批量生产的电芯进行全面、严格的性能测试，包括循环寿命、倍率性能、能量密度、高低温性能以及各类安全测试。同时，积极参与或主导行业内相关技术标准的制定，推动形成全固态电池产品的测试规范和质量评价体系。

  • 产业合作与技术转化：

    • 战略合作： 与电动汽车、储能、消费电子等领域的龙头企业建立战略合作关系，共同推动全固态电池技术的商业化应用。通过技术授权、合资建厂等多种形式，将研究成果快速转化为具有市场竞争力的产品。
    • 人才培养与技术输出： 依托本研究平台，培养一批具备全固态电池研发和产业化经验的高端人才，为行业输送新鲜血液。同时，积极开展技术咨询和培训服务，帮助合作企业解决技术难题，提升其在全固态电池领域的研发和生产能力。
    • 产业链上下游协同： 积极与上游材料供应商（如锂盐、正负极材料、固态电解质原料厂商）和下游电池应用集成商（如整车厂、储能系统集成商）建立紧密合作，构建健全的全固态电池产业链生态系统，共同推动技术进步和市场拓展。

通过上述应用推广价值的实现和中试产业化路径的落实，本研究将为我国在全固态锂金属电池这一战略性新兴产业中占据国际领先地位提供强劲动力，对国家能源安全、环境保护和经济可持续发展具有重大意义。

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参考文献

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With the widespread use of lithium-ion batteries in a wide range of consumer electronics products, the CE industry has undergone a dramatic shift. The Li-ion battery has emerged as the heart of electric cars, and the focus has now shifted to the automotive sector. Liquid crystal displays have evolved over time to meet the demands of automobiles. International research groups and the performance of production electric vehicles are used to discuss and inform vehicle-driven battery targets. There is still a lot of room for improvement in terms of energy, life expectancy, cost, safety, and fast-charging capabilities for LIBs suited for the automotive sector. In this study, a review of lithium-ion battery applications in electric vehicles is presented.

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There is a growing need for energy storage solutions with high energy density and high safety due to the quick growth of smart grids and electric cars. Although traditional liquid lithium-ion batteries have been commercialized, their energy density is close to the theoretical limit, and there are safety hazards such as electrolyte leakage and flammability. In contrast, all-solid-state lithium-ion-batteries (ASSLIBs) with non-combustible solid electrolytes can completely eliminate the risk of thermal runaway, making them the core direction of the next-generation energy storage technology. However, issues including the development of lithium dendrites and the high interfacial impedance between the solid electrolyte and the electrode have made it difficult to commercialize. This paper systematically reviews the key roles and design strategies of nanomaterials in the positive electrode, negative electrode and electrolyte of ASSLIBs. Through size effect, high specific surface area and controllable interface characteristics, nanomaterials provide innovative solutions for optimizing ion transport, suppressing volume expansion and enhancing interface stability. Research shows that nanotechnology significantly enhances the energy density, cycle life and fast charging performance of ASSLIBs through material nanoscale, composite structure design and interface optimization. In the future, through the integration of multi-disciplinary technologies and innovation in preparation processes, nanomaterials are expected to promote the commercial application of ASSLIBs in fields such as electric vehicles, and become the core technology of high-safety, high-energy-density energy storage technologies of the future.

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Chunxiang Xian, Qiyue Wang, Yang Xia, et al.
Small. 2023 Jun;19(24):e2208164. doi: 10.1002/smll.202208164. Epub 2023 Mar 14.
Solid-state lithium-sulfur batteries (SSLSBs) have attracted tremendous research interest due to their large theoretical energy density and high safety, which are highly important indicators for the development of next-generation energy storage devices. Particularly, safety and "shuttle effect" issues originating from volatile and flammable liquid organic electrolytes can be fully mitigated by switching to a solid-state configuration. However, their road to thecommercial application is still plagued with numerous challenges, most notably the intrinsic electrochemical instability of solid-state electrolytes (SSEs) materials and their interfacial compatibility with electrodes and electrolytes. In this review, a critical discussion on the key issues and problems of different types of SSEs as well as the corresponding optimization strategies are first highlighted. Then, the state-of-the-art preparation methods and properties of different kinds of SSE materials, and their manufacture, characterization and performance in SSLSBs are summarized in detail. Finally, a scientific outlook for the future development of SSEs and the avenue to commercial application of SSLSBs is also proposed.

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Gabin Yoon, Sewon Kim, Ju-Sik Kim
Adv Sci (Weinh). 2023 Sep;10(27):e2302263. doi: 10.1002/advs.202302263. Epub 2023 Aug 6.
Solid-state Li-metal batteries (based on solid-state electrolytes) offer excellent safety and exhibit high potential to overcome the energy-density limitations of current Li-ion batteries, making them suitable candidates for the rapidly developing fields of electric vehicles and energy-storage systems. However, establishing close solid-solid contact is challenging, and Li-dendrite formation in solid-state electrolytes at high current densities causes fatal technical problems (due to high interfacial resistance and short-circuit failure). The Li metal/solid electrolyte interfacial properties significantly influence the kinetics of Li-metal batteries and short-circuit formation. This review discusses various strategies for introducing anode interlayers, from the perspective of reducing the interfacial resistance and preventing short-circuit formation. In addition, 3D anode structural-design strategies are discussed to alleviate the stress caused by volume changes during charging and discharging. This review highlights the importance of comprehensive anode/electrolyte interface control and anode design strategies that reduce the interfacial resistance, hinder short-circuit formation, and facilitate stress relief for developing Li-metal batteries with commercial-level performance.

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Xilong Chen, Xiangjie Li, Lingjie Luo, et al.
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Pedro López‐Aranguren, Pierre Lannelongue, Javier Carrasco, et al.
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Jinsik Nam, Hanbyeol Lee, Oh B Chae
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Yi Chen, Ji Qian, Ke Wang, et al.
Adv Mater. 2025 Oct;37(39):e2502653. doi: 10.1002/adma.202502653. Epub 2025 Jul 10.
Inorganic solid-state electrolytes (ISEs) are critical components of solid-state batteries (SSBs), and their interfacial properties play a decisive role in battery performance. This paper systematically reviews the recent advances in the interfaces of ISEs. It begins by defining and classifying ISEs-encompassing oxides, sulfides, and halides-while highlighting their fundamental characteristics, potential applications, and existing interface challenges. The discussion extends to the composition, structure, and reaction phenomena at the interfaces of SSBs, focusing on how these factors influence internal resistance, cycling stability, and safety. We detail advanced microscopic and spectroscopic techniques employed to investigate interfacial microstructures and chemical properties, as well as electrochemical impedance spectroscopy and nuclear magnetic resonance for electrical and structural analysis, while also highlighting emerging modalities for interface characterization in SSBs. Additionally, we explore the role of informatics strategies, particularly high-throughput computing and machine learning, in predicting interfacial stability, calculating ionic transport properties, and screening new materials to optimize interface engineering. Despite noteworthy progress in understanding ISE interfaces, challenges remain that hinder the commercialization of SSBs. Future research efforts should prioritize the optimization of interfacial structures and properties through multi-scale and multi-technique approaches to further accelerate SSB development.

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Zhenjiang Yu, Xueyan Zhang, Chuankai Fu, et al.
Abstract Solid‐state electrolytes (SSEs) are attracting growing interest for next‐generation Li‐metal batteries with theoretically high energy density, but they currently suffer from safety concerns caused by dendrite growth, hindering their commercial applications. Interfaces between SSEs and solid lithium are argued to be crucial, affecting dendrite growth and determining solid‐state batteries (SSBs) performance. The buried and localized nature of the interface poses a huge challenge for direct characterization under working conditions. Recent review articles have been devoted to evaluating the conductivity and chemical stability of SSEs. Recognizing this, in this Review, the focus is on understanding lithium dendrite beyond conventional factors and offering a perspective on various surface/interface and microstructural phenomena that require close attention by both experimentalists and theoreticians. The complicated ion‐transport mechanism and chemomechanical information correlated with interface and lithium dendrite are discussed. Rational solutions are provided to engineer functional interfaces to suppress lithium dendrites and accelerate progress towards the commercialization of SSBs.

11Sulfide‐Based Solid‐State Electrolytes: Synthesis, Stability, and Potential for All‐Solid‐State BatteriesOpenAlex

Qing Zhang, Daxian Cao, Yi Ma, et al.
Due to their high ionic conductivity and adeciduate mechanical features for lamination, sulfide composites have received increasing attention as solid electrolyte in all-solid-state batteries. Their smaller electronegativity and binding energy to Li ions and bigger atomic radius provide high ionic conductivity and make them attractive for practical applications. In recent years, noticeable efforts have been made to develop high-performance sulfide solid-state electrolytes. However, sulfide solid-state electrolytes still face numerous challenges including: 1) the need for a higher stability voltage window, 2) a better electrode-electrolyte interface and air stability, and 3) a cost-effective approach for large-scale manufacturing. Herein, a comprehensive update on the properties (structural and chemical), synthesis of sulfide solid-state electrolytes, and the development of sulfide-based all-solid-state batteries is provided, including electrochemical and chemical stability, interface stabilization, and their applications in high performance and safe energy storage.

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Yuhao Liang, Hong Liu, Guoxu Wang, et al.
Abstract All‐solid‐state lithium batteries have emerged as a priority candidate for the next generation of safe and energy‐dense energy storage devices surpassing state‐of‐art lithium‐ion batteries. Among multitudinous solid‐state batteries based on solid electrolytes (SEs), sulfide SEs have attracted burgeoning scrutiny due to their superior ionic conductivity and outstanding formability. However, from the perspective of their practical applications concerning cell integration and production, it is still extremely challenging to constructing compatible electrolyte/electrode interfaces and developing available scale processing technologies. This review presents a critical overview of the current underlying understanding of interfacial issues and analyzes the main processing challenges faced by sulfide‐based all‐solid‐state batteries from the aspects of cost‐effective and energy‐dense design. Besides, the corresponding approaches involving interface engineering and processing protocols for addressing these issues and challenges are summarized. Fundamental and engineering perspectives on future development avenues toward practical application of high energy, safety, and long‐life sulfide‐based all‐solid‐state batteries are ultimately provided. image

13Interfacial challenges for all-solid-state batteries based on sulfide solid electrolytesOpenAlex

Shuo Wang, Ruyi Fang, Yutao Li, et al.
Sulfide solid electrolytes (e.g., lithium thiophosphates) have the highest room-temperature ionic conductivity (∼10−2 S cm−1) among solid Li-ion conductors so far, and thus have attracted ever-increasing attention for high energy-density and safety all-solid-state batteries (ASSBs). However, interfacial issues between sulfide electrolytes and electrodes have been the main challenges for their applications in ASSBs. The interfacial instabilities would occur due to side reactions of sulfides with electrodes, poor solid-solid contact, and lithium dendrites during charge/discharge cycling. In this review, we analyze the interfacial issues in ASSBs based on sulfide electrolytes, and in particular, discuss strategies for solving these interfacial issues and stabilize the electrode-electrolyte interfaces. Moreover, a perspective of the interfacial engineering for sulfide-based ASSBs is provided.

14Solid‐State Li–Metal Batteries: Challenges and Horizons of Oxide and Sulfide Solid Electrolytes and Their InterfacesOpenAlex

Kun Joong Kim, Moran Balaish, Masaki Wadaguchi, et al.
Abstract The introduction of new, safe, and reliable solid‐electrolyte chemistries and technologies can potentially overcome the challenges facing their liquid counterparts while widening the breadth of possible applications. Through tech‐historic evolution and rationally analyzing the transition from liquid‐based Li‐ion batteries (LIBs) to all‐solid‐state Li‐metal batteries (ASSLBs), a roadmap for the development of a successful oxide and sulfide‐based ASSLB focusing on interfacial challenges is introduced, while accounting for five parameters: energy density, power density, longterm stability, processing, and safety. First taking a strategic approach, this review dismantles the ASSLB into its three major components and discusses the most promising solid electrolytes and their most advantageous pairing options with oxide cathode materials and the Li metal anode. A thorough analysis of the chemical, electrochemical, and mechanical properties of the two most promising and investigated classes of inorganic solid electrolytes, namely oxides and sulfides, is presented. Next, the overriding challenges associated with the pairing of the solid electrolyte with oxide‐based cathodes and a Li‐metal anode, leading to limited performance for solid‐state batteries are extensively addressed and possible strategies to mitigate these issues are presented. Finally, future perspectives, guidelines, and selective interface engineering strategies toward the resolution of these challenges are analyzed and discussed.

15Optimization and progress of interface construction of ceramic oxide solid-state electrolytes in Li-metal batteriesOpenAlex

Qiujun Wang, Nana Bai, Yaqing Wang, et al.

16Interfaces between Ceramic and Polymer Electrolytes: A Comparison of Oxide and Sulfide Solid Electrolytes for Hybrid Solid-State BatteriesOpenAlex

Dominic Spencer Jolly, Dominic L. R. Melvin, Isabella D. R. Stephens, et al.
Hybrid solid-state batteries using a bilayer of ceramic and solid polymer electrolytes may offer advantages over using a single type of solid electrolyte alone. However, the impedance to Li+ transport across interfaces between different electrolytes can be high. It is important to determine the resistance to Li+ transport across these heteroionic interfaces, as well as to understand the underlying causes of these resistances; in particular, whether chemical interphase formation contributes to giving high resistances, as in the case of ceramic/liquid electrolyte interfaces. In this work, two ceramic electrolytes, Li3PS4 (LPS) and Li6.5La3Zr1.5Ta0.5O12 (LLZTO), were interfaced with the solid polymer electrolyte PEO10:LiTFSI and the interfacial resistances were determined by impedance spectroscopy. The LLZTO/polymer interfacial resistance was found to be prohibitively high but, in contrast, a low resistance was observed at the LPS/polymer interface that became negligible at a moderately elevated temperature of 50 °C. Chemical characterization of the two interfaces was carried out, using depth-profiled X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry, to determine whether the interfacial resistance was correlated with the formation of an interphase. Interestingly, no interphase was observed at the higher resistance LLZTO/polymer interface, whereas LPS was observed to react with the polymer electrolyte to form an interphase.

17How Metallic Protection Layers Extend the Lifetime of NASICON-Based Solid-State Lithium BatteriesOpenAlex

Francisco Javier Quintero Cortes, John A. Lewis, Jared Tippens, et al.
The use of solid-state electrolytes (SSEs) within batteries is a promising strategy to safely access the high capacity of lithium metal anodes. However, most SSEs with practical ionic conductivity are chemically unstable in contact with lithium metal, which is detrimental to battery performance. Lithium aluminum germanium phosphate (LAGP) is an SSE with high ionic conductivity (10−4-10−3 S cm−1) and good environmental stability, but it forms an amorphous interphase region that continuously grows in contact with Li, leading to chemo-mechanical failure within solid-state batteries. Here, we find that thin (∼30 nm) chromium interlayers deposited between the lithium electrode and LAGP extend cycle life to over 1000 h at moderate current densities (0.1–0.2 mA cm−2), compared to ∼30 h without protection. This significantly improved stability occurs because the metallic interlayer alters the trajectory of interphase formation and the nature of the electrochemical reaction at the interface. This work shows the promise of interface engineering for a variety of SSE materials within solid-state batteries, while emphasizing the necessity of understanding how protection layers affect dynamic evolution of interfaces.

18PEO based polymer-ceramic hybrid solid electrolytes: a reviewOpenAlex

Jingnan Feng, Li Wang, Yijun Chen, et al.
Compared with traditional lead-acid batteries, nickel-cadmium batteries and nickel-hydrogen batteries, lithium-ion batteries (LIBs) are much more environmentally friendly and much higher energy density. Besides, LIBs own the characteristics of no memory effect, high charging and discharging rate, long cycle life and high energy conversion rate. Therefore, LIBs have been widely considered as the most promising power source for mobile devices. Commonly used LIBs contain carbonate based liquid electrolytes. Such electrolytes own high ionic conductivity and excellent wetting ability. However, the use of highly flammable and volatile organic solvents in them may lead to problems like leakage, thermo runaway and parasitic interface reactions, which limit their application. Solid polymer electrolytes (SPEs) can solve these problems, while they also bring new challenges such as poor interfacial contact with electrodes and low ionic conductivity at room temperature. Many approaches have been tried to solve these problems. This article is divided into three parts to introduce polyethylene oxide (PEO) based polymer-ceramic hybrid solid electrolyte, which is one of the most efficient way to improve the performance of SPEs. The first part focuses on polymer-lithium salt (LiX) matrices, including their ionic conduction mechanism and impact factors for their ionic conductivity. In the second part, the influence of both active and passive ceramic fillers on SPEs are reviewed. In the third part, composite SPEs' preparation methods, including solvent casting and thermocompression, are introduced and compared. Finally, we propose five key points on how to make composite SPEs with high ionic conductivity for reference.

19Towards better Li metal anodes: Challenges and strategiesOpenAlex

Ying Zhang, Tong‐Tong Zuo, Jelena Popović, et al.

20Space–Charge Layer Effect at Interface between Oxide Cathode and Sulfide Electrolyte in All-Solid-State Lithium-Ion BatteryOpenAlex

Jun Haruyama, Keitaro Sodeyama, Liyuan Han, et al.
We theoretically elucidated the characteristics of the space–charge layer (SCL) at interfaces between oxide cathode and sulfide electrolyte in all-solid-state lithium-ion batteries (ASS-LIBs) and the effect of the buffer layer interposition, for the first time, via the calculations with density functional theory (DFT) + U framework. As a most representative system, we examined the interfaces between LiCoO2 cathode and β-Li3PS4 solid electrolyte (LCO/LPS), and the LiCoO2/LiNbO3/β-Li3PS4 (LCO/LNO/LPS) interfaces with the LiNbO3 buffer layers. The DFT+U calculations, coupling with a systematic procedure for interface matching, showed the stable structures and the electronic states of the interfaces. The LCO/LPS interface has attractive Li adsorption sites and rather disordered structure, whereas the interposition of the LNO buffer layers forms smooth interfaces without Li adsorption sites for both LCO and LPS sides. The calculated energies of the Li-vacancy formation and the Li migration reveal that subsurface Li in the LPS side can begin to transfer at the under-voltage condition in the LCO/LPS interface, which suggests the SCL growth at the beginning of charging, leading to the interfacial resistance. The LNO interposition suppresses this growth of SCL and provides smooth Li transport paths free from the possible bottlenecks. These aspects on the atomic scale will give a useful perspective for the further improvement of the ASS-LIB performance.

21Electrode/electrolyte interface and interface reactions of solid oxide cells: Recent development and advancesOpenAlex

Shuai He, San Ping Jiang
High temperature solid oxide cells (SOCs) consisted of solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs) are considered one of the most environmentally friendly and efficient energy conversion technology to store renewal energy from sun and wind in hydrogen and generate electricity from the fuels such as hydrogen and natural gas with high efficiency and very low greenhouse gas emission. Over the last few decades, the development of SOC technologies in particularly SOFCs has experienced significant progress and much of the recent research have paid great efforts in understanding the processes occurring at the electrode/electrolyte interfaces. As electrochemical reactions mainly proceed at the gas, electrode and electrolyte three phase boundaries (TPBs), the microstructure and properties of the electrode/electrolyte interfaces thus play a crucial role in determining the overall cell performance and durability. Herein, we review the progress and achievements in the fundamental researches of the electrode/electrolyte (mainly oxygen-conducting) interface evolution behavior under open circuit and polarization conditions. Studies involving interfacial phenomena such as interface formation and reactions, element segregation and diffusion, micropore formation and delamination are summarized and discussed in detail. Besides, the state of the art characterization techniques that have been employed to examine the interface behavior are reviewed. Finally, the challenges and prospects of the interface research in the improvement of the performance and durability of a SOC device are discussed.

22Interface issues between cathode and electrolyte in sulfide-based all-solid-state lithium batteries and improvement strategies of interface performance through cathode modificationOpenAlex

Chenglong Wang, Yinglei Wu, Sirui Wang, et al.

23Interfaces Between Cathode and Electrolyte in Solid State Lithium Batteries: Challenges and PerspectivesOpenAlex

Kaihui Nie, Yanshuai Hong, Jiliang Qiu, et al.
Solid state lithium batteries are widely accepted as promising candidates for next generation of various energy storage devices with the probability to realize improved energy density and superior safety performances. However, the interface between electrode and solid electrolyte remain a key issue that hinders practical development of solid state lithium batteries. In this review, we specifically focus on the interface between solid electrolytes and prevailing cathodes. The basic principles of interface layer formation are summarized and three kinds of interface layers can be categorized. For typical solid state lithium batteries, a most common and daunting challenge is to achieve and sustain intimate solid-solid contact. Meanwhile, different specific issues occur on various types of solid electrolytes, depending on the intrinsic properties of adjacent solid components. Our discussion mostly involves following electrolytes, including solid polymer electrolyte, inorganic solid oxide and sulfide electrolytes as well as composite electrolytes. The effective strategies to overcome the interface instabilities are also summarized. In order to clarify interfacial behaviors fundamentally, advanced characterization techniques with time, and atomic-scale resolution are required to gain more insights from different perspectives. And recent progresses achieved from advanced characterization are also reviewed here. We highlight that the cooperative characterization of diverse advanced characterization techniques is necessary to gain the final clarification of interface behavior, and stress that the combination of diverse interfacial modification strategies is required to build up decent cathode-electrolyte interface for superior solid state lithium batteries.

24Deciphering the critical degradation factors of solid composite electrodes with halide electrolytes: Interfacial reaction versus ionic transportOpenAlex

Jonghyeok Yun, Hong Rim Shin, Trung Dinh Hoang, et al.

25Boosting the Electrochemical Performance of All‐Solid‐State Batteries with Sulfide Li<sub>6</sub>PS<sub>5</sub>Cl Solid Electrolyte Using Li<sub>2</sub>WO<sub>4</sub>‐Coated LiCoO<sub>2</sub> CathodeOpenAlex

Zhen Sun, Yanqing Lai, Na Lv, et al.
Abstract Solid‐state batteries exhibit promising prospects due to their potential in terms of safety and energy density. Sulfide solid electrolytes have received much attention due to their high ionic conductivity (about 10 −2 S cm −1 ). However, high side reactions between solid sulfide electrolytes and oxide cathodes, such as LiCoO 2 , have hampered the development of all‐solid‐state sulfide batteries. Here, first‐principles calculations and experiments are combined to demonstrate a novel protective layer to cope with the Li 6 PS 5 Cl electrolyte and LiCoO 2 cathode interface problem. By uniformly coating LiCoO 2 with a layer of Li 2 WO 4 , the interfacial resistance (the 100th cycle) between the sulfide electrolyte and LiCoO 2 is reduced to about 68 Ω cm 2 , which is nearly 15 times lower than the premodified 1061 Ω cm 2 . The 2 wt% Li 2 WO 4 ‐coated LiCoO 2 (2%LWO‐LCO)/Li 6 PS 5 Cl/Li‐In all‐solid‐state battery exhibits satisfactory capacity and excellent cycling stability at room temperature (93% capacity retention after 100 cycles). Furthermore, the ab initio molecular dynamics based on the Perdew, Burke, and Ernzerhof density functional theory calculations show that Li 2 WO 4 can effectively prevent the diffusion of Co and O from LiCoO 2 into the Li 6 PS 5 Cl solid electrolyte. It is shown that molecular dynamics help predict the interfacial reactions in all‐solid‐state sulfide batteries.

26A gradient oxy-thiophosphate-coated Ni-rich layered oxide cathode for stable all-solid-state Li-ion batteriesOpenAlex

Jianwen Liang, Yuanmin Zhu, Xiaona Li, et al.
and 25 °C.

27Relevance of solid electrolytes for lithium-based batteries: A realistic viewOpenAlex

Bettina V. Lotsch, Joachim Maier
Pros and cons are discussed with respect to replacing liquid electrolytes in Li-based batteries by solid electrolytes. We primarily refer to electrochemical and mechanical parameters which are the most characteristic ones in this context. Rather than giving an exhaustive overview on available solid electrolytes, we briefly discuss various systems and mainly concentrate on the recently found ultrafast sulfide-based Li electrolytes as they reflect well the positive and negative aspects of using solids for high performance batteries.

28Editors' Choice—Understanding Chemical Stability Issues between Different Solid Electrolytes in All-Solid-State BatteriesOpenAlex

Nathalie Riphaus, Barbara Stiaszny, Hans Beyer, et al.
Sulfide-based solid electrolytes (SE) are quite attractive for application in all-solid-state batteries (ASSB) due to their high ionic conductivities and low grain boundary resistance. However, limited chemical and electrochemical stability demands for protection on both cathode and anode side. One promising concept to prevent unwanted reactions and simultaneously improve interfacial contacting at the anode side consists in applying a thin polymer film as interlayer between Li metal and the SE. In the present study, we investigated the combination of polyethylene oxide (PEO) based polymer films with the sulfide-based SE Li10SnP2S12 (LSPS). We analyzed their compatibility using both electrochemical and chemical techniques. A steady increase in the cell resistance during calendar aging indicated decomposition reactions at the interfaces. By means of X-ray photoelectron spectroscopy and further analytical methods, the formation of polysulfides, P–[S]n–P like bridged PS43− units and sulfite, SO32−, was demonstrated. We critically discuss potential reasons and propose a plausible mechanism for the degradation of LSPS with PEO. The main objective of this paper is to highlight the importance of understanding interfaces in ASSBs not only from an electrochemical perspective, but also from a chemical point of view.

29Investigation of the Suppression of Dendritic Lithium Growth with a Lithium-Iodide-Containing Solid ElectrolyteOpenAlex

Masakuni Takahashi, Toshiki Watanabe, Kentaro Yamamoto, et al.
All-solid-state lithium batteries that use lithium metal as the anode have extremely high energy densities. However, for lithium metal anodes to be used, lithium dendrite formation must be addressed. Recently, the addition of lithium iodide (LiI) to sulfide solid electrolytes was found to suppress lithium dendrite formation. It is unclear whether the cause of this suppression is the improvement of the ionic conductivity of the solid electrolyte itself or the electrochemical properties of the lithium metal/solid electrolyte interface. In this study, the cause of the suppression was quantitatively elucidated. The effect of the interphase on the dendrite growth of doping LiI into Li3PS4 was determined using X-ray absorption spectroscopy and X-ray computed tomography measurements. The results revealed that LiI-doped Li3PS4 suppressed the dendrite formation by maintaining the interface due to inhibition of the reductive decomposition of Li3PS4. In addition, annealed LiI-doped Li3PS4 showed a greater dendrite suppression ability as the ionic conductivity increased. From these results, we not only found that the physical properties of the lithium metal/solid electrolyte interface and the bulk ionic conductivity contribute to lithium dendrite suppression but also quantitatively determined the proportions of the contributions of these two factors.

30Sustained Release‐Driven Formation of Ultrastable SEI between Li<sub>6</sub>PS<sub>5</sub>Cl and Lithium Anode for Sulfide‐Based Solid‐State BatteriesOpenAlex

Ya Chen, Wenwen Li, Changzhi Sun, et al.
Abstract The sulfide‐type solid electrolyte (SSE) is considered a promising candidate for solid‐state lithium metal batteries (SSLMBs) owing to its advantages of superior ionic conductivity. Nevertheless, the incompatibility of the sulfide and lithium metal can result in undesirable interface resistance and rapid Li dendrite growth, which seriously hinders its commercial applications. Herein, inspired by the moderation and long duration of sustained release drug carriers when combined with active pharmaceutical ingredients in the biomedical field, poly (propylene carbonate) (PPC) and lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) gradually interact with a Li anode with constantly decreased Li/SSE interfacial resistance. In addition to intimate contact, the ultrastable LiF‐enriched solid electrolyte interphase (SEI) is in situ formed via a sustained release effect, which suppresses the Li dendrite effectively. As a result, the symmetric cells demonstrate stable cycling performance for 1200 h at a current density of 0.1 mA cm −2 and 300 h at 0.5 mA cm −2 . Moreover, LiFePO 4 / Li 6 PS 5 Cl /Li SSLMB delivers a high discharge capacity of over 132.8 mAh g −1 for 900 cycles at 1C with steady Coulombic efficiency. Therefore, this sustained release mechanism and its initially successful application in interfacial modification increase the potential for commercial applications of SSLMBs.

31High Ionic Conductive, Mechanical Robust Sulfide Solid Electrolyte Films and Interface Design for All‐Solid‐State Lithium Metal BatteriesOpenAlex

Dabing Li, Hong Liu, Chao Wang, et al.
Abstract All‐solid‐state lithium batteries (ASSLBs) are considered a promising technology for next‐generation energy storage systems due to their inherent safety. However, the conventional laboratory‐scale ASSLBs reported to date are based on pellet‐type structures with thick solid electrolyte layers, leading to challenges related to low energy densities and poor electrochemical performance. In this study, porous adhesive poly(ethylene vinyl acetate) (PEVA) scaffolds and polytetrafluoroethylene (PTFE) binders are utilized to interweave sulfide solid electrolytes into freestanding films with an ultra‐low thickness of 40 µm, high ionic conductivity of 1.1 mS cm −1 , and a high tensile strength of 74 MPa. To mitigate the reduction reaction between the PTFE binder and the lithium metal anode, a Li 3 N‐rich solid electrolyte interphase (SEI) in situ on lithium metal is formed, and the assembled symmetric cell shows excellent cycling stability within 800 h at the current density of 0.2 mA cm −2 and room temperature. Additionally, the ASSLBs using oxidatively stable Li 2 ZrCl 5 F in the composite cathode and the prepared solid electrolyte film demonstrate exceptional cycling performance and fast‐charging capability, with a high cell‐level energy density of 354.4 Wh kg −1 . The ASSLBs prepared by coupling E‐LPSCl film and stable interface design exhibit excellent electrochemical performance and a high cell‐level energy density.

32Distinguishing Bulk and Grain Boundary Transport of a Proton-Conducting Electrolyte by Combining Equivalent Circuit Scheme and Distribution of Relaxation Times AnalysesOpenAlex

Julia G. Lyagaeva, Gennady K. Vdovin, Dmitry A. Medvedev
Features of ionic transport across grains and along grain boundaries of solid oxide electrolyte materials play a key role in the efficient application of these materials in electrochemical devices including solid oxide fuel and electrolysis cells, membrane reactors, and electrochemical converters. In the present work, equivalent circuit scheme (ECS) and distribution of relaxation times (DRT) analyses were successfully utilized to distinguish the bulk and grain boundary resistances, both from each other and from the polarization resistance component. Considering a Ag|BCG|Ag symmetrical cell (where BCG = BaCe0.9Gd0.1O3−δ) as a simple model system, the complex impedance spectra were obtained. Due to the close characteristic parameters (relaxation time and capacitance) exhibited by some electrochemical processes, these spectra cannot be precisely resolved using only an ECS tool, although a joint application of ECS and DRT allowed the spectra to be deconvoluted. As a result, data concerning grain and grain boundary conductivities were obtained along with their activation energies. The good agreement of these data with those published in the literature indicates the correctness of the provided analysis. The presented results confirm the wide applicability of ECS/DRT for various electrochemical functions.

33Quantifying lithium enrichment at grain boundaries in Li7La3Zr2O12 solid electrolyte by correlative microscopyOpenAlex

Oana Cojocaru‐Mirédin, Johannes Schmieg, Marius Müller, et al.

34Ferroelastic toughening: Can it solve the mechanics challenges of solid electrolytes?OpenAlex

Anton Van der Ven, Robert M. McMeeking, Raphaële J. Clément, et al.
The most promising solid electrolytes for all-solid-state Li batteries are oxide and sulfide ceramics. Current ceramic solid electrolytes are brittle and lack the toughness to withstand the mechanical stresses of repeated charge and discharge cycles. Solid electrolytes are susceptible to crack propagation due to dendrite growth from Li metal anodes and to debonding processes at the cathode/electrolyte interface due to cyclic variations in the cathode lattice parameters. In this perspective, we argue that solutions to the mechanics challenges of all-solid-state batteries can be borrowed from the aerospace industry, which successfully overcame similar hurdles in the development of thermal barrier coatings of superalloy turbine blades. Their solution was to exploit ferroelastic and transformation toughening mechanisms to develop ceramics that can withstand cyclic stresses due to large variations in temperature. This perspective describes fundamental materials design principles with which to search for solid electrolytes that are ferroelastically toughened.

35Mitigating thermal expansion effects in solid oxide fuel cell cathodes: A critical reviewOpenAlex

Nilam Shah, Xiaoyong Xu, Jonathan Love, et al.
Solid oxide fuel cells (SOFCs) are a promising technology for clean electricity generation. However, their performance degradation over time and with thermal cycles due to thermal incompatibility remains a significant challenge in achieving the industrial scale. Designing a thermally compatible cathode material to overcome this issue is essential to withstand more thermal cycles. Rather than reviewing the cathode materials, this review critically examines recent advances in mitigating cathode/electrolyte thermal incompatibility and delamination via designing cathode materials and cathode-electrolyte interfaces. This critical review provides an overview of SOFC application, significant challenges, and the delamination mechanism, followed by an elaboration on experimental strategies to tailor the thermal expansion of cathodes to reduce or eliminate cathode delamination. In the last section, the remaining challenges and future research opportunities are discussed to support the design of thermally compatible cathode materials for SOFCs with high durability.

36Review on Polymer-Based Composite Electrolytes for Lithium BatteriesOpenAlex

Penghui Yao, Haobin Yu, Zhiyu Ding, et al.
Lithium-ion batteries have dominated the high performance and mobile market for last decade. Despite their dominance in many areas, the development of current commercial lithium-ion batteries is experiencing bottlenecks, limited by safety risks such as: leakage, burning, and even explosions due to the low-boiling point organic liquid electrolytes. Solid electrolyte is a promising option to solve or mitigate those issues. Among all solid electrolytes, polymer based solid electrolytes have the advantages of low flammability, good flexibility, excellent thermal stability, and high safety. Numerous researchers have focused on implementing solid polymer based Li-ion batteries with high performance. Nevertheless, low Li-ion conductivity and poor mechanical properties are still the main challenges in its commercial development. In order to tackle the issues and improve the overall performance, composites with external particles are widely investigated to form a polymer-based composite electrolyte. In light of their work, this review discusses the progress of polymer-based composite lithium ion's solid electrolytes. In particular, the structures, ionic conductivities, electrochemical/chemical stabilities, and fabrications of solid polymer electrolytes are introduced in the text and summarized at the end. On the basis of previous work, the perspectives of solid polymer electrolytes are provided especially toward the future of lithium ion batteries.

37A reflection on polymer electrolytes for solid-state lithium metal batteriesOpenAlex

Ziyu Song, Fangfang Chen, María Martínez‐Ibáñez, et al.
Before the debut of lithium-ion batteries (LIBs) in the commodity market, solid-state lithium metal batteries (SSLMBs) were considered promising high-energy electrochemical energy storage systems before being almost abandoned in the late 1980s because of safety concerns. However, after three decades of development, LIB technologies are now approaching their energy content and safety limits imposed by the rocking chair chemistry. These aspects are prompting the revival of research activities in SSLMB technologies at both academic and industrial levels. In this perspective article, we present a personal reflection on solid polymer electrolytes (SPEs), spanning from early development to their implementation in SSLMBs, highlighting key milestones. In particular, we discuss the SPEs' characteristics taking into account the concept of coupled and decoupled SPEs proposed by C. Austen Angell in the early 1990s. Possible remedies to improve the physicochemical and electrochemical properties of SPEs are also examined. With this article, we also aim to highlight the missing blocks in building ideal SSLMBs and stimulate research towards innovative electrolyte materials for future rechargeable high-energy batteries.

38Applications of Polymer Electrolytes in Lithium-Ion Batteries: A ReviewOpenAlex

Jayeeta Chattopadhyay, Tara Sankar Pathak, Diogo M.F. Santos
Polymer electrolytes, a type of electrolyte used in lithium-ion batteries, combine polymers and ionic salts. Their integration into lithium-ion batteries has resulted in significant advancements in battery technology, including improved safety, increased capacity, and longer cycle life. This review summarizes the mechanisms governing ion transport mechanism, fundamental characteristics, and preparation methods of different types of polymer electrolytes, including solid polymer electrolytes and gel polymer electrolytes. Furthermore, this work explores recent advancements in non-aqueous Li-based battery systems, where polymer electrolytes lead to inherent performance improvements. These battery systems encompass Li-ion polymer batteries, Li-ion solid-state batteries, Li-air batteries, Li-metal batteries, and Li-sulfur batteries. Notably, the advantages of polymer electrolytes extend beyond enhancing safety. This review also highlights the remaining challenges and provides future perspectives, aiming to propose strategies for developing novel polymer electrolytes for high-performance Li-based batteries.

39Incombustible Polymer Electrolyte Boosting Safety of Solid‐State Lithium Batteries: A ReviewOpenAlex

Longfei Han, Li Wang, Zonghai Chen, et al.
Abstract Lithium‐ion batteries with their portability, high energy density, and reusability are frequently used in today's world. Under extreme conditions, lithium‐ion batteries leak, burn, and even explode. Therefore, improving the safety of lithium‐ion batteries has become a focus of attention. Researchers believe using a solid electrolyte instead of a liquid one can solve the lithium battery safety issue. Due to the low price, good processability and high safety of the solid polymer electrolytes, increasing attention have been paid to them. However, polymer electrolytes can also decompose and burn under extreme conditions. Moreover, lithium dendrites are formed continuously due to the uneven charge distribution on the surface of the lithium metal anode. A short circuit caused by a lithium dendrite can cause the battery to thermal runaway. As a result, the safety of polymer solid‐state batteries remains a challenge. In this review, the thermal runaway mechanism of the batteries is summarized, and the batteries abuse test standard is introduced. In addition, the recent works on the high‐safety polymer electrolytes and the solution strategies of lithium anode problems in polymer batteries are reviewed. Finally, the development direction of safe polymer solid lithium batteries is prospected.

40Polymer-Based Solid-State BatteriesOpenAlex

Mingyang Xin, Yanan Li, Lina Cong, et al.
Polymer-based solid-state batteries exhibit desired properties of good safety and high energy density, and they are very likely to become the devices of choice for the next generation of energy storage. Among solid electrolytes, polyoxyethylene (PEO)-based polymer electrolytes are widely used in solid-state batteries. However, the electrochemical window of electrolytes themselves is narrow, which limits further improvement of energy density. At present, only LiFePO4 is suitable for paring with a PEO electrolyte, and such a limitation severely hinders the real-world application of PEO polymer solid-state batteries. In particular, the side reactions at the interface between the electrode material and the PEO polymer electrolyte are the main challenge that greatly shortens battery cycle life. To suppress these side reactions, people have adopted corresponding strategies and achieved considerable progress. In order to fully understand the changes at the interface of solid-state batteries, various advanced characterization methods have been employed. This will provide a more scientific basis for improving the cycle stability of solid-state batteries in the next stage.

41Surface Modification of Li-Rich Cathode Materials for Lithium-Ion Batteries with a PEDOT:PSS Conducting PolymerOpenAlex

Feng Wu, Jianrui Liu, Li Li, et al.
Composites of lithium-rich Li1.2Ni0.2Mn0.6O2 and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) ( PEDOT: PSS) are synthesized through coprecipitation followed by a wet coating method. In the resulting samples, the amorphous conductive polymer films on the surface of the Li1.2Ni0.2Mn0.6O2 particles are 5-20 nm thick. The electrochemical properties of Li1.2Ni0.2Mn0.6O2 are obviously enhanced after PEDOT: PSS coating. The composite sample with an optimal 3 wt % coating exhibits rate capability and cycling properties that are better than those of Li1.2Ni0.2Mn0.6O2, with an excellent initial discharge capacity of 286.5 mA h g(-1) at a current density of 0.1 C and a discharge capacity that remained at 146.9 mA h g(-1) at 1 C after 100 cycles. The improved performances are ascribed to the high conductivity of the PEDOT: PSS coating layer, which can improve the conductivity of the composite material. The PEDOT: PSS layer also suppresses the formation and growth of a solid electrolyte interface. Surface modification with PEDOT: PSS is a feasible approach for improving the comprehensive properties of cathode materials.

42Intrinsically Safe Lithium Metal Batteries Enabled by Thermo‐Electrochemical Compatible In Situ Polymerized Solid‐State ElectrolytesOpenAlex

Shi‐Jie Yang, Hong Yuan, Nan Yao, et al.
In situ polymerized solid-state electrolytes have attracted much attention due to high Li-ion conductivity, conformal interface contact, and low interface resistance, but are plagued by lithium dendrite, interface degradation, and inferior thermal stability, which thereby leads to limited lifespan and severe safety hazards for high-energy lithium metal batteries (LMBs). Herein, an in situ polymerized electrolyte is proposed by copolymerization of 1,3-dioxolane with 1,3,5-tri glycidyl isocyanurate (TGIC) as a cross-linking agent, which realizes a synergy of battery thermal safety and interface compatibility with Li anode. Functional TGIC enhances the electrolyte polymeric level. The unique carbon-formation mechanism facilitates flame retardancy and eliminates the battery fire risk. In the meantime, TGIC-derived inorganic-rich interphase inhibits interface side reactions and promotes uniform Li plating. Intrinsically safe LMBs with nonflammability and outstanding electrochemical performances under extreme temperatures (130 °C) are achieved. This functional polymer design shows a promising prospect for the development of safe LMBs.

43Super Soft All-Ethylene Oxide Polymer Electrolyte for Safe All-Solid Lithium BatteriesOpenAlex

Luca Porcarelli, Claudio Gerbaldi, Federico Bella, et al.
Here we demonstrate that by regulating the mobility of classic -EO- based backbones, an innovative polymer electrolyte system can be architectured. This polymer electrolyte allows the construction of all solid lithium-based polymer cells having outstanding cycling behaviour in terms of rate capability and stability over a wide range of operating temperatures. Polymer electrolytes are obtained by UV-induced (co)polymerization, which promotes an effective interlinking between the polyethylene oxide (PEO) chains plasticized by tetraglyme at various lithium salt concentrations. The polymer networks exhibit sterling mechanical robustness, high flexibility, homogeneous and highly amorphous characteristics. Ambient temperature ionic conductivity values exceeding 0.1 mS cm(-1) are obtained, along with a wide electrochemical stability window (>5 V vs. Li/Li(+)), excellent lithium ion transference number (>0.6) as well as interfacial stability. Moreover, the efficacious resistance to lithium dendrite nucleation and growth postulates the implementation of these polymer electrolytes in next generation of all-solid Li-metal batteries working at ambient conditions.

44Poly(ethylene oxide)/Poly(vinylidene fluoride)/Li6.4La3Zr1.4Ta0.6O12 composite electrolyte with a stable interface for high performance solid state lithium metal batteriesOpenAlex

Changjiang Bai, Zhenguo Wu, Wei Xiang, et al.

45Particles in composite polymer electrolyte for solid-state lithium batteries: A reviewOpenAlex

Nan Meng, Xiaogang Zhu, Fang Lian
Solid-state lithium batteries (SSLBs) have been identified as one kind of the most promising energy conversion and storage devices because of their safety, high energy density, and long cycling life. The development of solid-state electrolyte is vital to commercialize SSLBs. Composite polymer electrolyte (CPE), derived by compositing inorganic particles into solid polymer electrolyte has become the most practical species for SSLBs because it inherits the advantages of polymer electrolyte and simultaneously achieves enhanced ionic conductivity and mechanical properties. The characteristics of inorganic particles and their interaction with polymers strongly impact the performance of CPE, improving its ionic conductivity, mechanical properties, thermal and electrochemical stability, as well as interface compatibility with both electrodes. In this review, the effects of particle characteristics including its species, size, proportion, morphology on the ionic conductivity and mechanical properties of CPE are reviewed. Meanwhile, some novel composite strategies are also introduced including surface modification, hybridization, and alignment of particles in polymer matrices, as well as some new preparation methods of CPE. The interactions between particles and other components in CPE including polymer matrices or lithium salt are particularly focused herein to reveal the lithium conductive mechanism. Finally, a perspective on the direction of future CPE development for SSLBs is presented.

46Achieving high-performance parameters in NASICON-polymer composite electrolyte-based solid-state supercapacitors by interface modificationOpenAlex

Neha Neha, Anshuman Dalvi
is achieved at 3 V/5 mA. Moreover, after 10 000 galvanostatic charge-discharge cycles (1 V/1 mA), the supercapacitor exhibits ∼99% stable coulombic efficiency along with appreciably high capacitance retention (∼90%). A stack of five such cells can power an 8 V LED circuit for more than 30 minutes. Applying such a solvent layer enables effective use of the surface area of the activated carbon. Results suggest that solvent incorporation enables a local 'gel-like' layer formation that couples the electrode with a solid polymer electrolyte and facilitates faster charge movement across the electrode-electrolyte interface.

47Emerging Strategies for Gel Polymer Electrolytes with Improved Dual-Electrode Side Regulation Mechanisms for Lithium-Sulfur Batteries.PubMed

Yingyue Cui, Jin Li, Xuedi Yuan, et al.
Chem Asian J. 2022 Nov 2;17(21):e202200746. doi: 10.1002/asia.202200746. Epub 2022 Sep 22.
Although GPE still has the risk of shuttling due to the incomplete removal of liquid electrolytes compared to SPE, which has the most promise of eliminating polysulfide shuttling, researchers have made abundant efforts to eliminate as much of the polysulfide shuttling effect as possible while retaining the unique advantages of GPE. For example, physical barrier to polysulfides by improving the pore size of GPE or fabricating multidimensional structures by different preparation methods. Further chemical adsorption of polysulfides by adding nanofillers to increase polar sites to create polar-polar interactions with polysulfides or to create Lewis acid-base interactions. However, although chemical adsorption can indeed highly immobilize polysulfides, it still brings disadvantages such as loss of active material. Therefore, other researchers have employed GPE with ion-selective permeability that has electrostatic repulsive force or steric hindrance to polysulfides to better inhibit polysulfide shuttling. However, modifying only the cathode side is not enough to enhance this overall properties of Li-S cells. These problems of poor Li transport, lithium dendrite growth, and poor SEI due to uneven lithium ion deposit on Li anode side still affect the overall performance of Li-S cells. Therefore, a GPE to improve these problems on the Li anode side is summarized below. Compared with an all-solid electrolyte, GPE, which has a partially liquid electrolyte, clearly has advantages such as strong interfacial contact, good anode interface compatibility, and high flexibility. However, it is still not comparable to the ionic conductivity, etc. of pure liquid electrolyte only. Therefore, the problems on the lithium metal anode side are mainly focused on the lithium ion transport problems and the problems of lithium dendrite growth and inhomogeneous SEI at the lithium anode interface. Facing the problems in these two aspects, researchers have given many improvement solutions respectively. For the lithium ion transport problem, researchers have instead provided pathways for lithium ion transport by adding amorphous nanofibers or nanofillers to reduce the crystallinity of the polymer and improve the ionic conductivity. Alternatively, the migration number of lithium ions can be increased by limiting the anions in the electrolyte. As for the interfacial problems of lithium anodes, researchers have effectively suppressed the growth of lithium dendrites or inhomogeneous lithium plating/stripping phenomena mainly by adding nanofillers to increase the mechanical strength of GPE or by participating in the generation of SEI.

48Metal organic framework reinforced polymer electrolyte with high cation transference number to enable dendrite-free solid state Li metal conversion batteriesOpenAlex

Xiaoxue Wu, Keyi Chen, Zhenguo Yao, et al.

49PDOL-Based Solid Electrolyte Toward Practical Application: Opportunities and ChallengesOpenAlex

Hua Yang, Mao‐xiang Jing, Li Wang, et al.
Polymer solid-state lithium batteries (SSLB) are regarded as a promising energy storage technology to meet growing demand due to their high energy density and safety. Ion conductivity, interface stability and battery assembly process are still the main challenges to hurdle the commercialization of SSLB. As the main component of SSLB, poly(1,3-dioxolane) (PDOL)-based solid polymer electrolytes polymerized in-situ are becoming a promising candidate solid electrolyte, for their high ion conductivity at room temperature, good battery electrochemical performances, and simple assembly process. This review analyzes opportunities and challenges of PDOL electrolytes toward practical application for polymer SSLB. The focuses include exploring the polymerization mechanism of DOL, the performance of PDOL composite electrolytes, and the application of PDOL. Furthermore, we provide a perspective on future research directions that need to be emphasized for commercialization of PDOL-based electrolytes in SSLB. The exploration of these schemes facilitates a comprehensive and profound understanding of PDOL-based polymer electrolyte and provides new research ideas to boost them toward practical application in solid-state batteries.

50An effective solid-electrolyte interphase for stable solid-state batteriesOpenAlex

Keming Song, Weihua Chen

51Solid-state batteries: The critical role of mechanicsOpenAlex

Sergiy Kalnaus, Nancy J. Dudney, Andrew S. Westover, et al.
Solid-state batteries with lithium metal anodes have the potential for higher energy density, longer lifetime, wider operating temperature, and increased safety. Although the bulk of the research has focused on improving transport kinetics and electrochemical stability of the materials and interfaces, there are also critical challenges that require investigation of the mechanics of materials. In batteries with solid-solid interfaces, mechanical contacts, and the development of stresses during operation of the solid-state batteries, become as critical as the electrochemical stability to keep steady charge transfer at these interfaces. This review will focus on stress and strain that result from normal and extended battery cycling and the associated mechanisms for stress relief, some of which lead to failure of these batteries.

52On the Origin of Zero Interface Resistance in the LiAlLaZrO|Li System: An Atomistic Investigation.PubMed

Lisette Haarmann, Jochen Rohrer, Karsten Albe
ACS Appl Mater Interfaces. 2021 Nov 10;13(44):52629-52635. doi: 10.1021/acsami.1c15400. Epub 2021 Oct 28.
Understanding the nature of ion transfer at the interface between Li metal and solid electrolytes (SE) is essential for further optimization of all-solid-state Li-ion batteries. Thus, the Li transfer across the SE|Li metal interface is investigated by means of ab initio calculations based on density functional theory in this work. The aluminum-doped garnet LiAlLaZrO (LLZO) is considered as a model SE due to its practical stability against Li metal. A low-energy interface model in bicrystal geometry is constructed and investigated by nudged elastic band calculations as well as ab initio molecular dynamics (AIMD) simulations. In order to distinguish between interface and bulk transport in the AIMD simulations, a post-processing protocol is developed. We find that the activation energies and diffusivities of Li are comparable in bulk LLZO and across the interface, substantiating that the interface kinetics are not rate-limiting. Moreover, electronic structure analysis indicates that charge transfer occurs gradually. Finally, Al loss of LLZO at the interface rationalizes the experimentally observed phase transition from cubic to tetragonal observed close to Li metal contacts.

53Negating interfacial impedance in garnet-based solid-state Li metal batteriesOpenAlex

Xiaogang Han, Yunhui Gong, Kun Fu, et al.

54Solid-State Electrolytes for Lithium-Ion Batteries: Fundamentals, Challenges and PerspectivesOpenAlex

Wenjia Zhao, Yi Jin, Ping He, et al.
Abstract With the rapid popularization and development of lithium-ion batteries, associated safety issues caused by the use of flammable organic electrolytes have drawn increasing attention. To address this, solid-state electrolytes have become the focus of research for both scientific and industrial communities due to high safety and energy density. Despite these promising prospects, however, solid-state electrolytes face several formidable obstacles that hinder commercialization, including insufficient lithium-ion conduction and surge transfer impedance at the interface between solid-state electrolytes and electrodes. Based on this, this review will provide an introduction into typical lithium-ion conductors involving inorganic, organic and inorganic–organic hybrid electrolytes as well as the mechanisms of lithium-ion conduction and corresponding factors affecting performance. Furthermore, this review will comprehensively discuss emerging and advanced characterization techniques and propose underlying strategies to enhance ionic conduction along with future development trends. Graphical Abstract

55Design and Optimization of Composite Cathodes for Solid-State Batteries Using Hybrid Carbon Networks with Facile Electronic and Ionic Percolation Pathways.PubMed

Kyung Oh Kim, Sang-Hoon Park, Hye-Bin Chun, et al.
ACS Appl Mater Interfaces. 2023 Aug 2;15(30):36748-36758. doi: 10.1021/acsami.3c04394. Epub 2023 Jul 19.
Solid-state batteries (SSBs) have emerged as a promising alternative to conventional liquid electrolyte batteries due to their potential for higher energy density and improved safety. However, achieving high performance in SSBs is difficult because of inadequate contact and interfacial reactions that generate high interfacial resistance, as well as inadequate solid-solid contact between electrodes. These chronic issues are associated with inhomogeneous ion and electron transport networks owing to imperfect solid-solid interfacial contact. This study developed an optimal interfacial engineering strategy to facilitate an ion-electron transport network by designing an active material (NCM622) uniformly filled with a thin layer of a solid electrolyte (garnet-type LiGaLaZrO) and conductive additives. The optimal composite electrode architecture enhanced the high capacity, high rate capability, and long-term cycle stability, even at room temperature, owing to the percolating network for facile ionic conduction that assured a homogeneous reaction. In addition to mitigating the mechanical degradation of the cathode electrode, it also reduced the crosstalk effects on the anode-solid electrolyte interface. Effectively optimizing the selection and use of conductive additives in composite electrodes offers a promising approach to addressing key performance-limiting factors in SSBs, including interfacial resistance and solid-solid contact issues. This study underscores the critical importance of cathode architecture design for achieving high-performance SSBs by ensuring that the interfaces are intact with solid electrolytes at both the cathode and anode interfaces while promoting uniform reactions. This study provides valuable insights into the development of SSBs with improved performance, which could have significant implications for a wide range of applications.

56High electronic conductivity as the origin of lithium dendrite formation within solid electrolytesOpenAlex

Fudong Han, Andrew S. Westover, Jie Yue, et al.

57Li<sup>+</sup> Transport Mechanism at the Heterogeneous Cathode/Solid Electrolyte Interface in an All-Solid-State Battery via the First-Principles Structure Prediction SchemeOpenAlex

Bo Gao, Randy Jalem, Yanming Ma, et al.
High interfacial resistance between a cathode and solid electrolyte (SE) has been a long-standing problem for all-solid-state batteries (ASSBs). Though thermodynamic approaches suggested possible phase transformations at the interfaces, direct analyses of the ionic and electronic states at the solid/solid interfaces are still crucial. Here, we used our newly constructed scheme for predicting heterogeneous interface structures via the swarm-intelligence-based crystal structure analysis by particle swarm optimization method, combined with density functional theory calculations, and systematically investigated the mechanism of Li-ion (Li+) transport at the interface in LiCoO2 cathode/β-Li3PS4 SE, a representative ASSB system. The sampled favorable interface structures indicate that the interfacial reaction layer is formed with both mixing of Co and P cations and mixing of O and S anions. The calculated site-dependent Li chemical potentials μLi(r) and potential energy surfaces for Li+ migration across the interfaces reveal that interfacial Li+ sites with higher μLi(r) values cause dynamic Li+ depletion with the interfacial electron transfer in the initial stage of charging. The Li+-depleted space can allow oxidative decomposition of SE materials. These pieces of evidence theoretically confirm the primary origin of the observed interfacial resistance in ASSBs and the mechanism of the resistance decrease observed with oxide buffer layers (e.g., LiNbO3) and oxide SE. The present study also provides a perspective for the structure sampling of disordered heterogeneous solid/solid interfaces on the atomic scale.

58Introducing Jahn-Teller Distortion in Inorganic Solid-State Electrolytes to Improve Ionic Conductivity.PubMed

Xiaolong Xu, Zhiliang Xiu, Huaping Zhao, et al.
Small. 2026 Mar;22(14):e09616. doi: 10.1002/smll.202509616. Epub 2026 Jan 17.
The Jahn-Teller distortion, a geometric distortion in crystals to lower the energy in a specific electronic configuration, is avoided in electrode materials as it damages the battery under an electric field. In contrast to its conventional role in electrodes, we pioneer the reasonable application of Jahn-Teller distortion to solve the sodium ion transmission issues caused by grain boundaries and voids of inorganic solid-state electrolytes (ISEs) in solid-state batteries. Based on high-spin manganese ions (Mn), it reveals that expanding interplanar spacing and forming the Mn doped NaZrSiPO (NZSPM) glassy phases among NZSPM crystalline grains through introducing Jahn-Teller distortion significantly enhances sodium ion transport by widening the sodium ion transport channel, weakening grain boundaries, and eliminating voids in ISEs. As-formed NZSPM crystal-NZSPM glass (C-G) ISE provides an ionic conductivity of 0.498 mS cm. Moreover, the Na||C-G||NaNiFeMnO(NFM) cell delivers the performance comparable to traditional batteries (e.g.,>120 mAh g at 0.1 C), but no dendrites are formed. Our findings advance the understanding of Jahn-Teller distortion and provide guidelines for designing the nano-microstructure of functional materials.

59Li–Solid Electrolyte Interfaces/Interphases in All-Solid-State Li BatteriesOpenAlex

Linan Jia, Jinhui Zhu, Xi Zhang, et al.
Abstract The emergence of all-solid-state Li batteries (ASSLBs) represents a promising avenue to address critical concerns like safety and energy density limitations inherent in current Li-ion batteries. Solid electrolytes (SEs) show significant potential in curtailing Li dendrite intrusion, acting as natural barriers against short circuits. However, the substantial challenges at the SEs−electrode interface, particularly concerning the anode, pose significant impediments to the practical implementation of ASSLBs. This review aims to delineate the most viable strategies for overcoming anode interfacial hurdles across four distinct categories of SEs: sulfide SEs, oxide SEs, polymer SEs, and halide SEs. Initially, pivotal issues such as anode interfacial side reactions, inadequate physical contact, and Li dendrite formation are comprehensively outlined. Furthermore, effective methodologies aimed at enhancing anode interfacial stability are expounded, encompassing approaches like solid electrolyte interface (SEI) interlayer insertion, SE optimization, and the adoption of Li alloy in lieu of Li metal, each tailored to specific SE categories. Moreover, this review presents novel insights into fostering interfaces between diverse SE types and Li anodes, while also advocating perspectives and recommendations for the future advancement of ASSLBs. Graphical Abstract

60Electrochemical Stability of Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub> and Li<sub>7</sub>La<sub>3</sub>Zr<sub>2</sub>O<sub>12</sub> Solid ElectrolytesOpenAlex

Fudong Han, Yizhou Zhu, Xingfeng He, et al.
The electrochemical stability window of solid electrolyte is overestimated by the conventional experimental method using a Li/electrolyte/inert metal semiblocking electrode because of the limited contact area between solid electrolyte and inert metal. Since the battery is cycled in the overestimated stability window, the decomposition of the solid electrolyte at the interfaces occurs but has been ignored as a cause for high interfacial resistances in previous studies, limiting the performance improvement of the bulk‐type solid‐state battery despite the decades of research efforts. Thus, there is an urgent need to identify the intrinsic stability window of the solid electrolyte. The thermodynamic electrochemical stability window of solid electrolytes is calculated using first principles computation methods, and an experimental method is developed to measure the intrinsic electrochemical stability window of solid electrolytes using a Li/electrolyte/electrolyte‐carbon cell. The most promising solid electrolytes, Li 10 GeP 2 S 12 and cubic Li‐garnet Li 7 La 3 Zr 2 O 12 , are chosen as the model materials for sulfide and oxide solid electrolytes, respectively. The results provide valuable insights to address the most challenging problems of the interfacial stability and resistance in high‐performance solid‐state batteries.

61Garnet‐type solid‐state electrolytes: crystal structure, interfacial challenges and controlling strategiesOpenAlex

Tingting Wu, Sijie Guo, Bing Li, et al.
Abstract All‐solid‐state batteries (ASSBs) hold great promise for next‐generation energy storage technologies owing to their advantage in different aspects such as energy density, safety, and wide temperature tolerance. However, the use of solid‐state electrolytes (SSEs) instead of liquid ones meanwhile brings serious concerns related to the point‐to‐point contact between SSEs and electrodes, which is known to result in high interface resistance and inhomogeneous distribution of charges during the Li + plating/stripping process, eventually leading to a premature failure of ASSBs. This review focuses on the garnet‐type SSEs in the formula of Li 7 La 3 Zr 2 O 12 (LLZO), and discusses the structure‐performance relationship of this ceramic electrolyte in detail to achieve a clear understanding of its Li + transmission mechanism. Meanwhile, the challenges of cubic phase LLZO (c‐LLZO) for their application in solid‐state batteries (SSBs) are demonstrated by the Li/LLZO interface, which features the importance of Li metal wettability and dendrite suppression for sustainable performance. Furthermore, this review summarizes the recent research strategies to combat these contact issues at the Li/LLZO interface, highlighting the essential role played by surface modification of LLZO electrolytes. Following the obtained insights, perspectives for future research on LLZO to accelerate its potential development of SSBs in commercialized applications are also provided.

62Real-Time Observation of Mechanical Evolution of Micro-Sized Si Anodes by In Situ Atomic Force MicroscopyOpenAlex

Jian Liu, Su Yeon Lee, Jung‐Woo Yoo, et al.
Pulverization of Si particles and the subsequent loss of electrical contact is a well-known degradation mechanism in most Si-based anodes, but the underlying electrochemical–mechanical coupling behavior in actual battery cells is still poorly understood. In this work, we employed in situ atomic force microscopy (AFM) to characterize the morphological evolution of microsized Si (μSi) anode during electrochemical cycling in real time. As a result, we successfully visualized important mechanical evolution on the cross-section of μSi anode such as initial pulverization, onset of particle crack formation and its patterns, irreversible volumetric changes, fresh solid electrolyte interface (SEI) formation at cracked surfaces, and particle isolations. In addition, we revealed via in situ AFM that limiting the upper cutoff voltage (e.g., <0.7 VvsLi) can suppress the mechanical failure of a μSi anode and subsequently improve capacity retention with a reduced cell impedance. These results demonstrated the potential of the proposed in situ AFM as a powerful technique that can identify electrochemical–mechanical behaviors of various energy-storage materials at the “real-world” electrode level.

63Atomic Origin of Chemomechanical Failure of Layered Cathodes in All-Solid-State BatteriesOpenAlex

Chunyang Wang, Yaqi Jing, D D Zhu, et al.
The ever-increasing demand for safety has thrust all-solid-state batteries (ASSBs) into the forefront of next-generation energy storage technologies. However, the atomic mechanisms underlying the failure of layered cathodes in ASSBs, as opposed to their counterparts in liquid electrolyte-based lithium-ion batteries (LIBs), have remained elusive. Here, leveraging artificial intelligence-enhanced super-resolution electron microscopy, we unravel the atomic origins dictating the chemomechanical degradation of technologically crucial high-Ni layered oxide cathodes in ASSBs. We reveal that the coupling of surface frustration and interlayer-shear-induced phase transformation exacerbates the chemomechanical breakdown of layered cathodes. Surface frustration, a phenomenon previously unobserved in liquid electrolyte-based LIBs, emerges through electrochemical processes involving surface nanocrystallization coupled with rock salt transformation. Simultaneously, delithiation-induced interlayer shear yields the formation of chunky O1 phases and intricate interfaces/transition motifs, distinct from scenarios observed in liquid electrolyte-based LIBs. Bridging the knowledge gap between the failure mechanisms of layered cathodes in solid-state electrolytes and conventional liquid electrolytes, our study provides unprecedented atomic-scale insights into the degradation pathways of layered cathodes in ASSBs.

64Challenges and Strategies of Low‐Pressure All‐Solid‐State BatteriesOpenAlex

Jiaxu Zhang, Jiamin Fu, Pushun Lu, et al.
All-solid-state batteries (ASSBs) are regarded as promising next-generation energy storage technology owing to their inherent safety and high theoretical energy density. However, achieving and maintaining solid-solid electronic and ionic contact in ASSBs generally requires high-pressure fabrication and high-pressure operation, posing substantial challenges for large-scale production and application. In recent years, significant efforts are made to address these pressure-related challenges. In this review, the impact of pressure on ASSBs is explored. First, the categories, origins, and challenges associated with pressure in ASSBs are outlined. Second, an overview of recent advancements in addressing pressure-related issues in ASSBs is provided, focusing on electrode materials and their interfaces with various solid-state electrolytes (SSEs). Third, advanced characterizations and simulations employed to unravel the intricate electrochemical-mechanical interactions in ASSBs are examined. Finally, existing strategies and the insights on achieving low-stack-pressure ASSBs are presented.

65Electrochemical-mechanical coupling failure mechanism of composite cathode in all-solid-state batteriesOpenAlex

Chunhao Yuan, Wenquan Lu, Jun Xu

66Electro–Chemo–Mechanical Failure of Solid Electrolytes Induced by Growth of Internal Lithium FilamentsOpenAlex

Xieyu Xu, Yangyang Liu, Olesya O. Kapitanova, et al.
Growth of lithium (Li) filaments within solid electrolytes, leading to mechanical degradation of the electrolyte and even short circuit of the cell under high current density, is a great barrier to commercialization of solid-state Li-metal batteries. Understanding of this electro-chemo-mechanical phenomenon is hindered by the challenge of tracking local fields inside the solid electrolyte. Here, a multiphysics simulation aiming to investigate evolution of the mechanical failure of the solid electrolyte induced by the internal growth of Li is reported. Visualization of local stress, damage, and crack propagation within the solid electrolyte enables examination of factors dominating the degradation process, including the geometry, number, and size of Li filaments and voids in the electrolyte. Relative damage induced by locally high stress is found to preferentially occur in the region of the electrolyte/Li interface having great fluctuations. A high number density of Li filaments or voids triggers integration of damage and crack networks by enhanced propagation. This model is built on coupling of mechanical and electrochemical processes for internal plating of Li, revealing evolution of multiphysical fields that can barely be captured by the state-of-the-art experimental techniques. Understanding mechanical degradation of solid electrolytes with the presence of Li filaments paves the way to design advanced solid electrolytes for future solid-state Li-metal batteries.

67Influence of Physical Parameters on Lithium Dendrite Growth Based on Phase Field TheoryOpenAlex

Wenqian Hao, Fengkai Guo, Jingyang Li, et al.
Lithium batteries have emerged as the mainstream technology in the current energy storage field due to their advantages, such as high energy density and long cycle life. However, from a multi-physics coupling perspective, research remains relatively scarce regarding the analysis of dendrite nucleation and growth, as well as their influence on lithium dendrite growth. Based on the phase field theory, this study develops a mechanical-thermal-electrochemical coupling model to systematically investigate the evolution mechanisms and suppression strategies of lithium dendrites induced by relevant physical quantities through the coupled effects of mechanical, thermal, and electrochemical fields. The dynamic behavior of the solid-solid interface is characterized by introducing order parameters. The governing nonlinear partial differential equations are formulated by combining the Cahn-Hilliard and Ginzburg-Landau equations. The present numerical results and the previous results are compared to validate the present model in properly predicting lithium dendrite growth. Numerical simulations are performed to analyze the influence of various physical parameters, such as electric potential, anisotropic intensity and anisotropic modulus, on the morphological evolution of lithium dendrites. These findings provide critical insights for advancing strategies to suppress lithium dendrite growth and enhance battery performance in solid-state lithium batteries under multi-field coupling conditions.

68Electrochemical-mechanical coupled phase-field modeling for lithium dendrite growth in all-solid-state lithium metal batteriesOpenAlex

Guoqing Qi, Xunliang Liu, Xiaoping Yi, et al.

69Evaluating Interfacial Stability in Solid-State Pouch Cells via Ultrasonic ImagingOpenAlex

Hanyu Huo, Kai Huang, Wei Luo, et al.
Chemical/electrochemical stability at the interfaces greatly affects the performance of solid-state batteries (SSBs). However, the interfacial behavior in SSBs remains elusive due to the subsurface nature of interfaces and the lack of proper characterization methods. Herein, ultrasonic imaging is employed to nondestructively investigate the interfacial stability in solid-state pouch cells. Benefiting from the high sensitivity of ultrasound to the gas/vacuum, operando ultrasonic imaging can effectively probe the inner gas release and interfacial degradation in pouch cells during long-term cycling. The gradual oxidation at the cathode interface is tracked, while the increased interfacial resistance from either contact loss or passivation layer growth is well distinguished. Moreover, the safety issue of SSBs is highlighted by the flammable gas release detected in ultrasonic images. Ultrasonic imaging is demonstrated to be a powerful tool to evaluate the interfacial stability in SSBs, which can guide the rational design of interfaces and enhance the performance of SSBs.

70Electro-chemo-mechanical modeling of solid-state batteriesOpenAlex

Ting Hei Wan, Francesco Ciucci

71Modeling the electro-chemo-mechanical failure at the lithium-solid electrolyte interface: Void evolution and lithium penetrationOpenAlex

Ruqing Fang, Wei Li, Junning Jiao, et al.
The solid-solid contact interface is crucial for the reliability of solid-state energy storage systems. The contact condition becomes more complicated when lithium (Li) metal is used as the anode. The contact between solid electrolyte (SE) and Li metal is inferior compared to the liquid/solid interface in conventional Li-ion batteries. Experimental evidence has shown that improper operating conditions of solid-state batteries can lead to electro-chemo-mechanical failures at the Li/SE interface, including the formation of voids and the penetration of Li. In this study, a unified phase-field model is developed to investigate these two mechanisms. The model considers the coupled electro-chemo-mechanical processes including void diffusion, lattice annihilation, stripping and plating reactions, and plastic deformation of Li metal. The study begins with a revisit of the deformation-mechanism map for Li metal under a wide range of temperatures, stress, and deformation rates. This map serves as the basis for the mechanical characterization in the phase-field model. The large inelastic deformation of Li is considered by introducing an advection term into the Allen-Cahn equation, which is used to describe the dynamic evolution of the Li and void phases. The effects of current density and stack pressure on void evolution and Li penetration are studied based on the model predictions. By combining the simulation results with the experimental data from publications, we obtain the stable operation zone of stack pressure and applied current density. In this zone, the Li/SE interface can enable stable stripping and plating of Li metal. The same phase-field modeling framework is transferred to investigate the Li-Mg alloy/SE interface considering Li-Mg alloy is also used as the anode. The fundamental difference between Li/SE and Li-Mg/SE is analyzed accordingly. This study provides a useful tool for the design, manufacturing, and management of next-generation batteries by providing important scientific insights into the electro-chemo-mechanical processes of different anode materials under various operational conditions.

72A cohesive phase-field fracture model for chemo-mechanical environments: Studies on degradation in battery materialsOpenAlex

Shahed Rezaei, Jacob Niikoi Okoe-Amon, Cerun Alex Varkey, et al.

73Regulated lithium ionic flux through well-aligned channels for lithium dendrite inhibition in solid-state batteriesOpenAlex

Yang Li, Daxian Cao, William Arnold, et al.

74Linking the Defects to the Formation and Growth of Li Dendrite in All‐Solid‐State BatteriesOpenAlex

Hongchun Wang, Haowen Gao, Xiaoxuan Chen, et al.
Abstract The nucleation and growth of Li metal during deposition and the associated dendrite penetration are the critical and fundamental issues influencing the safety and power density of solid‐state lithium metal batteries (SSLBs). However, investigations on Li metal deposition/dissolution especially the formation and growth of Li dendrites and their determining factors in the all‐solid‐state electrochemical systems are still lacking. In this work, in situ observations of the Li metal growth process, and defects induced heterogeneous deposition under cathodic load, are reported. By exploiting in situ scanning electron microscopy, along with electrochemical analytical approaches, the spatial distribution and morphological evolution of the deposited Li at the electrode|solid electrolyte interface are obtained and discussed. This investigation reveals that the formation of lithium whiskers is decided by the local Li ion flux and the deposition active sites, which are closely dependent on the content and types of defects in the polycrystalline electrolyte. Moreover, the defect regions exhibit faster Li deposition kinetics and higher nucleation tendency. These results can advance the fundamental understanding of the Li penetration mechanism in SSLBs.

75Controlling Dendrite Growth in Solid-State ElectrolytesOpenAlex

He Liu, Xin‐Bing Cheng, Jia‐Qi Huang, et al.
Solid-state electrolytes (SSEs) are widely considered as an “enabler” to inhibit dendrite growth of lithium-metal anodes for high-energy and highly safe next-generation batteries. However, recent studies demonstrated that lithium dendrites form in working SSEs. Theoretically, dendrite inhibition can be achieved in perfect SSEs without any defects, while dendrite growth is extensively observed in practical SSEs with poor interface stability, large grain boundaries, voids, and partial electronic conductivity. In this Review, dendrite growth behaviors in SSEs, including polymer and inorganic electrolytes, are comprehensively summarized. The observed dendrite morphology in these SSEs, possible formation mechanisms, and some solutions are analyzed. Clear perspectives and some suggestions are also presented for the further development of SSEs in lithium-metal batteries. This Review intends to shed fresh light on the understanding of dendrite growth in SSEs and the rational design of the architecture and materials for SSEs matching the lithium-metal anode.

76Electro–Chemo–Mechanical Issues at the Interfaces in Solid‐State Lithium Metal BatteriesOpenAlex

Peng Wang, Wenjie Qu, Wei‐Li Song, et al.
Abstract Effective solid‐state interfacial contact of both the cathode and lithium metal anode with the solid electrolyte (SE) are required to improve the performance of solid‐state lithium metal batteries (SSBs). Electro–chemo–mechanical coupling (ECMC) strongly affects the interfacial stability of SSBs. On one hand, mechanical stress strongly influences interfacial contact and causes side reactions. On the other hand, electrochemical reactions such as lithium deposition cause mechanical deformation and stress at electrode/SE interfaces. To solve the degradation/failure problems of interfaces and provide guidelines to construct high‐performance SSBs, the ECMC at electrode/SE interfaces should be comprehensively investigated. In this review, the problems associated with ECMC at electrode/SE interfaces are summarized. The interfacial degradation/failure mechanisms, including the contact and electrochemical stability of interfaces, are introduced. Mechanical factors affecting interfacial contact and lithium deposition are highlighted. Experimental observation and computational analysis methods for electrode/SE interfaces are then summarized. Strategies to construct stable electrode/SE interfaces, such as assembling stress and wetting layers to improve interfacial contact, 3D SE structure, and plating stress relief to suppress lithium dendrite formation, are reviewed. The remaining challenges to better understanding ECMC and related solutions to aid SSB development are discussed.

77Lithium Dendrite in All-Solid-State Batteries: Growth Mechanisms, Suppression Strategies, and CharacterizationsOpenAlex

Daxian Cao, Xiao Sun, Qiang Li, et al.

78Dendrite growth and inhibition in all-solid-state lithium metal batteries: <i>in situ</i> optical observationOpenAlex

Haowen Liu, Weining Jiang, Wenjie Chen, et al.
Combining in situ optical microscopy, we are able to monitor the real-time evolution of dendrite pathways in pressurized all-solid-state cells and understand the dendrite growth mechanism in working solid-state cells.

79Influence of Electrolyte Modulus on the Local Current Density at a Dendrite Tip on a Lithium Metal ElectrodeOpenAlex

Katherine J. Harry, Kenneth Higa, Venkat Srinivasan, et al.
Understanding and controlling the electrochemical deposition of lithium is imperative for the safe use of rechargeable batteries with a lithium metal anode. Solid block copolymer electrolyte membranes are known to enhance the stability of lithium metal anodes by mechanically suppressing the formation of lithium protrusions during battery charging. Time-resolved hard X-ray microtomography was used to monitor the internal structure of a symmetric lithium-polymer cell during galvanostatic polarization. The microtomography images were used to determine the local rate of lithium deposition, i.e. local current density, in the vicinity of a lithium globule growing through the electrolyte. Measurements of electrolyte displacement enabled estimation of local stresses in the electrolyte. At early times, the current density was maximized at the globule tip, as expected from simple current distribution arguments. At later times, the current density was maximized at the globule perimeter. We show that this phenomenon is related to the local stress fields that arise as the electrolyte is deformed. The local current density, normalized for the radius of curvature, decreases with increasing compressive stresses at the lithium-polymer interface. To our knowledge, our study provides the first direct measurement showing the influence of local mechanical stresses on the deposition kinetics at lithium metal electrodes.

80Layered Polymer Stacking for Stable Interfaces and Dendrite Growth Inhibition in All-Solid-State Lithium BatteriesOpenAlex

Long Hu, Xue Gao, Ziyong Li, et al.
at 60 °C and retains 81.6% after 500 cycles under 1 C among 2.8-4.4 V. These results demonstrate the strong electrochemical compatibility of the sandwich-CPE, enabling high reversible capacity and good cycling stability for solid-state Li batteries with different cathodes at different temperatures and current rates.

81Scalable ultrathin solid electrolyte from recycled Antheraea pernyi silk with regulated ion transport for solid-state Li–S batteriesOpenAlex

Lu Nie, Li Yang, Xiaoyan Wu, et al.
Ultrathin solid-state electrolytes (SSEs) with rapid Li + transport are ideal for developing high-energy-density all-solid-state lithium metal batteries. However, a significant challenge remains in balancing the intrinsic trade-off between electrochemical performance and mechanical properties. Herein, Antheraea pernyi fibers recycled from waste silk textiles are utilized as the raw materials to construct a porous and strong supporting skeleton for fabricating ultrathin SSE. This skeleton not only provides efficient three-dimensional Li + transport channels, but also immobilizes Li-salt anions, resulting in homogenized Li + flux and local current density distribution, thereby promoting uniform Li deposition. As a result, the obtained ultrathin SSE exhibits excellent ion-regulated properties, enhanced electrochemical stability, and superior dendrite suppression. Additionally, the formation of an inorganic-rich solid electrolyte interface layer is beneficial for stabilizing the interface contact between the SSE and Li anode. The solid-state Li|sulfurized polyacrylonitrile (Li|SPAN) cell delivers an excellent capacity retention of 92.3% after 500 cycles at 1 ​C. Moreover, the prepared high-voltage Li|LiCoO 2 pouch cell exhibits a capacity retention of 90.1% at 0.2 ​C after 200 cycles. This work presents an economically effective strategy for reutilizing waste textiles as ion-conducting mechanical supports for energy storage applications. • Recycled Antheraea pernyi ​fibers from waste textiles construct a porous and strong skeleton for ultrathin SSE. • This skeleton provides 3D Li + ​transport channels, immobilizes Li-salt anions, ensuring uniform Li deposition.

82Manipulating the diffusion energy barrier at the lithium metal electrolyte interface for dendrite-free long-life batteriesOpenAlex

Jyotshna Pokharel, Arthur v. Cresce, Bharat Pant, et al.
N-rich SEI. These studies may cast new insight into the design and engineering of an ideal artificial SEI for stable and high-performance lithium metal batteries.

83A strategy of selective and dendrite-free lithium deposition for lithium batteriesOpenAlex

Jingwei Xiang, Ying Zhao, Lixia Yuan, et al.

84Nano-zirconia boosting the ionic conductivity and lithium dendrite inhibition ability of a poly(1,3-dioxolane) solid electrolyte for high-voltage solid-state lithium batteriesOpenAlex

Bin Deng, Mao‐xiang Jing, Lin‐xin Li, et al.
YSZ nanoparticles greatly enhanced the ionic conductivity and lithium dendrite inhibition ability of a PDOL solid electrolyte membrane.

85Electrode structure enabling dendrite inhibition for high cycle stability quasi-solid-state lithium metal batteriesOpenAlex

Kaiming Wang, Ao Yu, Zhiyi Zhou, et al.

86Stack Pressure Considerations for Room‐Temperature All‐Solid‐State Lithium Metal BatteriesOpenAlex

Jean‐Marie Doux, Han Nguyen, Darren H. S. Tan, et al.
Abstract All‐solid‐state batteries are expected to enable batteries with high energy density with the use of lithium metal anodes. Although solid electrolytes are believed to be mechanically strong enough to prevent lithium dendrites from propagating, various reports today still show cell failure due to lithium dendrit growth at room temperature. While cell parameters such as current density, electrolyte porosity, and interfacial properties have been investigated, mechanical properties of lithium metal and the role of applied stack pressure on the shorting behavior are still poorly understood. Here, failure mechanisms of lithium metal are investigated in all‐solid‐state batteries as a function of stack pressure, and in situ characterization of the interfacial and morphological properties of the buried lithium is conducted in solid electrolytes. It is found that a low stack pressure of 5 MPa allows reliable plating and stripping in a lithium symmetric cell for more than 1000 h, and a Li | Li 6 PS 5 Cl | LiNi 0.80 Co 0.15 Al 0.05 O 2 full cell, plating more than 4 µm of lithium per charge, is able to cycle over 200 cycles at room temperature. These results suggest the possibility of enabling the lithium metal anode in all‐solid‐state batteries at reasonable stack pressures.

87Bidirectionally Compatible Buffering Layer Enables Highly Stable and Conductive Interface for 4.5 V Sulfide‐Based All‐Solid‐State Lithium BatteriesOpenAlex

Longlong Wang, Xingwei Sun, Jun Ma, et al.
Abstract High‐voltage all‐solid‐state lithium batteries (HVASSLBs) are considered attractive systems for portable electronics and electric vehicles, due to their theoretically high energy density and safety. However, realization of HVASSLBs with sulfide solid electrolytes (SEs) is hindered by their limited electrochemical stability, resulting in sluggish interphase dynamics. Here, a bidirectionally compatible buffering layer design scheme is proposed to overcome the interfacial challenges of sulfide‐based HVASSLBs. As a proof of concept, it is found that NASICON‐type Li x Zr 2 (PO 4 ) 3 surprisingly exhibit great compatibility with both 4.5 V LiCoO 2 and Li 6 PS 5 Cl, based on the results of first‐principles calculations and various in situ/ex situ characterizations. This compatibility significantly restrains the interface reactivity and boosts interfacial Li‐ion transport. Therefore, 4.5 V sulfide‐based HVASSLBs can exhibit remarkably enhanced initial discharge capacity (143.3 vs 125.9 mAh·g −1 at 0.2C), capacity retention (95.53% vs 74.74% after 100 cycles), and rate performance (97 vs 45 mAh·g −1 at 2C). This work sheds light on the great prospects of sulfide‐based HVASSLBs with high‐rate characteristics, and constitutes a crucial step toward the rational design of interface and interphase chemistry for high‐performance sulfide‐based HVASSLBs.

88"Win-Win" Modification of LiCoO Enables Stable and Long-Life Cycling of Sulfide-Based All Solid-State Batteries.PubMed

Guozhong Lu, Ying Jiang, Xiang Wu, et al.
ChemSusChem. 2023 Oct 20;16(20):e202300517. doi: 10.1002/cssc.202300517. Epub 2023 Aug 7.
Interfacial side reactions and space charge layers between the oxide cathode material and the sulfide solid-state electrolytes (SSEs), along with the structural degradation of the active material, significantly compromise the electrochemical performance of all-solid-state batteries (ASSLBs). Surface coating and bulk doping of the cathodes are considered the most effective approaches to mitigate the interface issues between the cathode and SSEs and enhance the structural integrity of composite cathodes. Here, a one-step low-cost means is ingeniously designed to modify LiCoO (LCO) with heterogeneous Li TiO /Li(TiMg) O surface coating and bulk gradient Mg doping. When applied in Li GeP S -based ASSLBs, the Li TiO and Li(TiMg) O coating layers effectively suppress interfacial side reactions and weaken space charge layer effect. Furthermore, gradient Mg doping stabilizes the bulk structure to mitigate the formation of spinel-like phases during local overcharging caused by solid-solid contact. The modified LCO cathodes exhibit excellent cycle performance with a capacity retention of 80 % after 870 cycles. This dual-functional strategy provides the possibility for large-scale commercial implementation of cathodes modification in sulfide based ASSLBs in the future.

89Surface Engineering Strategy Enables 4.5 V Sulfide-Based All-Solid-State Batteries with High Cathode Loading and Long Cycle LifeOpenAlex

Kangjun Wang, Ziteng Liang, Suting Weng, et al.
Sulfide-based all-solid-state lithium batteries (ASSLBs) with LiCoO2 (LCO) operating at high voltage (≥4.5 V vs Li+/Li) hold promise in realizing high energy density while maintaining safety. Here, we propose a solid electrolyte coating strategy to stabilize the cathode electrolyte interface and demonstrate the benefit of lithium difluoro(oxalate)borate (LiDFOB) as coating layer on the surface of Li6PS5Cl (LPSCl) to improve the performance of LCO at 4.5 V. 89.3% of initial discharge capacity can be retained after 1500 cycles at 1C (1C = 150 mA g–1). ASSLBs with high cathode loading (35.7 mg cm–2) could deliver an areal capacity over 6 mAh cm–2 (167 mAh g–1) at 0.1C and keep 85% capacity retention after 200 cycles at 0.3C. The investigation of the improvement mechanism further verifies that in situ decomposition of LiDFOB would build an (electro)chemomechanically stable interface, which not only suppresses interfacial side reactions but also buffers the cathode cracking.

90Improving Interfacial Stability for All-Solid-State Secondary Batteries with Precursor-Based Gradient Doping.PubMed

Yong Jun Ji, Yong Joon Park
ACS Omega. 2024 Feb 5;9(7):8405-8416. doi: 10.1021/acsomega.3c09545. eCollection 2024 Feb 20.
Recently, sulfide solid-state electrolytes with excellent ionic conductivity and facile electrode integration have gained prominence in the field of all-solid-state batteries (ASSBs). However, owing to their inherently high reactivity, sulfide electrolytes interact with the cathode, forming interfacial layers that adversely affect the electrochemical performance of all-solid-state cells. Unlike conventional cathode-coating methods that involve the formation of surface coatings from high-cost source materials, the proposed strategy involves the doping of precursors with low-cost oxides (NbO, TaO, and LaO) prior to cathode fabrication. This novel approach aims to improve the stability of the cathode-sulfide electrolyte interface. Notably, doping significantly improved the discharge capacity, rate capability, and cyclic performance of cathodes while reducing their impedance resistance. Scanning electron microscopy, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) indicated a gradient dopant-concentration profile (with a high level of dopant at the surface) in the doped cathodes. Cathode doping, particularly with Nb and Ta, caused a reduction in cation mixing owing to crystal-structure adjustments and ionic-conductivity enhancements. XPS and high-resolution TEM confirmed that gradient doping effectively minimized cathodic side reactions, possibly due to the formation of a coating-like protective layer in the cathode-electrolyte interface coupled with structural stabilization attributed to the doping process. The protective ability of the interfacial layer generated by gradient doping was confirmed to be comparable to that of conventional surface coatings. Therefore, this study could guide the future development of low-cost, high-performance ASSBs, opening new frontiers in sustainable energy storage.

91High-Performance Single-Crystal Lithium-Rich Layered Oxides Cathode Materials via NaWO-Assisted Sintering.PubMed

Jidong Duan, Fengqi Wang, Mengjie Huang, et al.
Small. 2024 Apr;20(15):e2307998. doi: 10.1002/smll.202307998. Epub 2023 Nov 27.
Single-crystal lithium-rich layered oxides (LLOs) with excellent mechanical properties can enhance their crystal structure stability. However, the conventional methods for preparing single-crystal LLOs, require large amounts of molten salt additives, involve complicated washing steps, and increase the difficulty of large-scale production. In this study, a sodium tungstate (NaWO)-assisted sintering method is proposed to fabricate high-performance single-crystal LLOs cathode materials without large amounts of additives and additional washing steps. During the sintering process, NaWO promotes particle growth and forms a protective coating on the surface of LLOs particles, effectively suppressing the side reactions at the cathode/electrolyte interface. Additionally, trace amounts of Na and W atoms are doped into the LLOs lattice via gradient doping. Experimental results and theoretical calculations indicate that Na and W doping stabilizes the crystal structure and enhances the Li ions diffusion rate. The prepared single-crystal LLOs exhibit outstanding capacity retention of 82.7% (compared to 65.0%, after 200 cycles at 1 C) and a low voltage decay rate of 0.76 mV per cycle (compared to 1.80 mV per cycle). This strategy provides a novel pathway for designing the next-generation high-performance cathode materials for Lithium-ion batteries (LIBs).

92An Artificial Solid Electrolyte Interphase with High Li‐Ion Conductivity, Mechanical Strength, and Flexibility for Stable Lithium Metal AnodesOpenAlex

Yayuan Liu, Dingchang Lin, Pak Yan Yuen, et al.
An artificial solid electrolyte interphase (SEI) is demonstrated for the efficient and safe operation of a lithium metal anode. Composed of lithium-ion-conducting inorganic nanoparticles within a flexible polymer binder matrix, the rationally designed artificial SEI not only mechanically suppresses lithium dendrite formation but also promotes homogeneous lithium-ion flux, significantly enhancing the efficiency and cycle life of the lithium metal anode.

93Stable Artificial Solid Electrolyte Interphases for Lithium BatteriesOpenAlex

Lin Ma, Mun Sek Kim, Lynden A. Archer
A rechargeable lithium metal battery (LMB), which uses metallic lithium as the anode, is among the most promising technologies for next generation electrochemical energy storage devices due to its high energy density, particularly when Li is paired with energetic conversion cathodes such as sulfur, oxygen/air, and oxygen–carbon dioxide mixtures. Practical LMBs in any of these designs remain elusive due to multiple problems, including parasitic reactions of Li metal with liquid electrolytes, unstable/dendritic electrodeposition at the anode during cell recharge, and chemical reaction of dissolved cathode conversion products with the Li anode. The solid electrolyte interphase (SEI) formed between lithium metal and liquid electrolytes plays a critical role in all of these processes. We report on the chemistry and interfacial properties of artificial SEI films created by in situ reaction of a strong Lewis acid AlI3, Li metal, and aprotic liquid electrolytes. The study takes advantage of the strong surface affinity of I– ions to initiate polymerization of dioxolane at the Li metal surface and to localize beneficial halide salts in the formed polymeric SEI thin film. We find that these SEI films impart chemical and electrochemical stability to a Li metal anode. We further show that the improvements come from at least three processes: (i) creation of a stable oligomer thin film on the Li anode, (ii) formation of a LiI salt layer at the interface, and (iii) in situ formation of a Li–Al alloy.

94Ionic conductive polymers as artificial solid electrolyte interphase films in Li metal batteries – A reviewOpenAlex

Shilun Gao, Feiyuan Sun, Nian Liu, et al.

95Flexible Composite Solid Electrolyte Facilitating Highly Stable “Soft Contacting” Li–Electrolyte Interface for Solid State Lithium‐Ion BatteriesOpenAlex

Luyi Yang, Zijian Wang, Yancong Feng, et al.
Abstract A flexible composite solid electrolyte membrane consisting of inorganic solid particles (Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 ), polyethylene oxide (PEO), and boronized polyethylene glycol (BPEG) is prepared and investigated. This membrane exhibits good stability against lithium dendrite, which can be attributed to its well‐designed combination components: the compact inorganic lithium ion conducting layer provides the membrane with good mechanical strength and physically barricades the free growth of lithium dendrite; while the addition of planar BPEG oligomers not only disorganizes the crystallinity of the PEO domain, leading to good ionic conductivity, but also facilitates a “soft contact” between interfaces, which not only chemically enables homogeneous lithium plating/stripping on the lithium metal anode, but also reduces the polarization effects. In addition, by employing this membrane to a LiFePO 4 /Li cell and testing its galvanostatic cycling performances at 60 °C, capacities of 158.2 and 94.2 mA h g −1 are delivered at 0.1 C and 2 C, respectively.

96Ceramic Rich Composite Electrolytes: An Overview of Paradigm Shift toward Solid Electrolytes for High‐Performance Lithium‐Metal BatteriesOpenAlex

Dheeraj Kumar Maurya, Behrouz Bazri, Pavitra Srivastava, et al.
Abstract Exploiting the synergy between organic polymer electrolytes and inorganic electrolytes via the development of composite electrolytes can suggest solutions to the current challenges of next‐generation solid‐state lithium‐metal batteries (SSLMBs). Depending upon a mass fraction of inorganic fillers and organic polymers, composite electrolytes are broadly classified into “ceramic‐in‐polymer” (CIP) and “polymer‐in‐ceramic” (PIC) categories, inheriting distinct structure and electrochemical properties. Since the stability and electrochemical characteristics of the inorganic phase are superior to those of the organic phase for lithium‐ion conduction, applying lithium‐enrich active filler in PIC seems more promising. The inorganic phase preserves the primary migratory channels in the PIC electrolyte, while the viscoelastic properties attempt to be introduced from the organic binder or host. The present work overviews the studies on state‐of‐the‐art PIC electrolytes, the fundamental mechanism of ionic conduction, preparation methods, and current progress in materials development for SSLMBs. In addition, the modification strategies for improving the electrode–electrolyte interface are also emphasized. Moreover, it further prospects the current challenges and effective strategies for the future development of PICs‐based CPEs to accelerate the practical application of SSLMBs. This review examines the progress and outlook of PIC‐based electrolytes for next‐generation lithium batteries.

97External Pressure in Polymer-Based Lithium Metal Batteries: An Often-Neglected Criterion When Evaluating Cycling Performance?OpenAlex

Philipp Roering, Gerrit Michael Overhoff, Kun Ling Liu, et al.
Solid-state batteries based on lithium metal anodes, solid electrolytes, and composite cathodes constitute a promising battery concept for achieving high energy density. Charge carrier transport within the cells is governed by solid-solid contacts, emphasizing the importance of well-designed interfaces. A key parameter for enhancing the interfacial contacts among electrode active materials and electrolytes comprises externally applied pressure onto the cell stack, particularly in the case of ceramic electrolytes. Reports exploring the impact of external pressure on polymer-based cells are, however, scarce due to overall better wetting behavior. In this work, the consequences of externally applied pressure in view of key performance indicators, including cell longevity, rate capability, and limiting current density in single-layer pouch-type NMC622||Li cells, are evaluated employing cross-linked poly(ethylene oxide), xPEO, and cross-linked cyclodextrin grafted poly(caprolactone), xGCD-PCL. Notably, externally applied pressure substantially changes the cell's electrochemical cycling performance, strongly depending on the mechanical properties of the considered polymers. Higher external pressure potentially enhances electrode-electrolyte interfaces, thereby boosting the rate capability of pouch-type cells, despite the fact that the cell longevity may be reduced upon plastic deformation of the polymer electrolytes when passing beyond intrinsic thresholds of compressive stress. For the softer xGCD-PCL membrane, cycling of cells is only feasible in the absence of external pressure, whereas in the case of xPEO, a trade-off between enhanced rate capability and minimal membrane deformation is achieved at cell pressures of ≤0.43 MPa, which is considerably lower and more practical compared to cells employing ceramic electrolytes with ≥5 MPa external pressure.

98Research Progress and Application of PEO-Based Solid State Polymer Composite ElectrolytesOpenAlex

Danyang Zhang, Lina Li, Xiaochao Wu, et al.
As a high-efficiency energy storage and conversion device, lithium-ion batteries have high energy density, and have received widespread attention due to their good cycle performance and high reliability. However, currently commercial lithium batteries usually use organic solutions containing various lithium salts as liquid electrolytes. In practical applications, liquid electrolytes have many shortcomings and shortcomings, such as poor chemical stability, flammability, and explosion. Therefore, the liquid electrolyte has a great safety hazard. The use of solid electrolyte ensures the safety of lithium-ion batteries, and has the advantages of high energy density, good cycle performance, long life, and wide electrochemical window, making the battery safer and more durable, with higher energy density and simple battery Structural design. Solid electrolytes mainly include inorganic solid electrolytes and organic polymer solid electrolytes. Although both inorganic solid electrolytes and polymer solid electrolytes have their own advantages, as far as the existing research work is concerned, whether it is an inorganic system or a polymer system, a single-system solid electrolyte can never achieve the full performance of an ideal solid electrolyte. The composite solid electrolyte composed of active or passive inorganic filler and polymer matrix is considered as a promising candidate electrolyte for all-solid-state lithium batteries. Among many polymer systems, PEO-based is considered to be the most ideal polymer substrate. In this review article, we first introduced the structure, properties, and preparation methods of PEO-based polymer electrolytes. Furthermore, the researches related to the modification of PEO-based polymer solid electrolytes in recent years are summarized. The contribution of polymer structural modification and the introduction of additives to the ionic conductivity, electrochemical stability and mechanical properties of PEO-based solid electrolytes is described. Examples of different composite solid electrolyte design concepts were extensively discussed, such as inorganic inert nanoparticles/PEO, oxide/PEO, and sulfide/PEO. Finally, the future development direction of composite solid electrolytes was prospected.

99Promoted ion conductivity of sodium salt–poly(ethylene oxide) polymer electrolyte induced by adding conductive beta-alumina and application in all-solid-state sodium batteriesOpenAlex

Yiwei Yao, Zehua Liu, Xinxin Wang, et al.

100Stabilization of Lithium Metal Anodes by Hybrid Artificial Solid Electrolyte InterphaseOpenAlex

Alexander C. Kozen, Chuan‐Fu Lin, Oliver Zhao, et al.
Li metal is among the most attractive anode materials for secondary batteries, with a theoretical specific capacity > 3800 mAh g–1. However, its extremely low electrochemical potential is associated with high chemical reactivity that results in undesirable reduction of electrolyte species on the lithium surface, leading to spontaneous formation of a solid electrolyte interphase (SEI) with uncontrolled composition, morphology, and physicochemical properties. Here, we demonstrate a new approach to stabilize Li metal anodes using a hybrid organic/inorganic artificial solid electrolyte interphase (ASEI) deposited directly on the Li metal surface by self-healing electrochemical polymerization (EP) and atomic layer deposition (ALD). This hybrid protection layer is thin, flexible, ionically conductive, and electrically insulating. We show that Li metal protected by the hybrid protection layer gives rise to very stable cycling performance for over 300 cycles at current density 1 mA/cm2 and over 110 cycles at current density 2 mA/cm2, well above the threshold for dendrite growth at unprotected Li. Our strategy for protecting Li metal anodes by hybrid organic/inorganic ASEI represents a new approach to mitigating or eliminating dendrite formation at reactive metal anodes—illustrated here for Li—and may expedite the realization of a "beyond-Li-ion" battery technology employing Li metal anodes (e.g., Li–S).

101Interfacial Evolution of Lithium Dendrites and Their Solid Electrolyte Interphase Shells of Quasi‐Solid‐State Lithium‐Metal BatteriesOpenAlex

Yang Shi, Jing Wan, Gui‐Xian Liu, et al.
Unstable electrode/solid-state electrolyte interfaces and internal lithium dendrite penetration hamper the applications of solid-state lithium-metal batteries (SSLMBs), and the underlying mechanisms are not well understood. Herein, in situ optical microscopy provides insights into the lithium plating/stripping processes in a gel polymer electrolyte and reveals its dynamic evolution. Spherical lithium deposits evolve into moss-like and branch-shaped lithium dendrites with increasing current densities. Remarkably, the on-site-formed solid electrolyte interphase (SEI) shell on the lithium dendrite is distinctly captured after lithium stripping. Inducing an on-site-formed SEI shell with an enhanced modulus to wrap the lithium precipitation densely and uniformly can regulate dendrite-free behaviors. An in-depth understanding of lithium dendrite evolution and its functional SEI shell will aid in the optimization of SSLMBs.

102Understanding materials challenges for rechargeable ion batteries with in situ transmission electron microscopyOpenAlex

Yifei Yuan, Khalil Amine, Jun Lü, et al.
Abstract An in-depth understanding of material behaviours under complex electrochemical environment is critical for the development of advanced materials for the next-generation rechargeable ion batteries. The dynamic conditions inside a working battery had not been intensively explored until the advent of various in situ characterization techniques. Real-time transmission electron microscopy of electrochemical reactions is one of the most significant breakthroughs poised to enable radical shift in our knowledge on how materials behave in the electrochemical environment. This review, therefore, summarizes the scientific discoveries enabled by in situ transmission electron microscopy, and specifically emphasizes the applicability of this technique to address the critical challenges in the rechargeable ion battery electrodes, electrolyte and their interfaces. New electrochemical systems such as lithium–oxygen, lithium–sulfur and sodium ion batteries are included, considering the rapidly increasing application of in situ transmission electron microscopy in these areas. A systematic comparison between lithium ion-based electrochemistry and sodium ion-based electrochemistry is also given in terms of their thermodynamic and kinetic differences. The effect of the electron beam on the validity of in situ observation is also covered. This review concludes by providing a renewed perspective for the future directions of in situ transmission electron microscopy in rechargeable ion batteries.

103Interface Limited Lithium Transport in Solid-State BatteriesOpenAlex

Dhamodaran Santhanagopalan, Danna Qian, Thomas McGilvray, et al.
Understanding the role of interfaces is important for improving the performance of all-solid-state lithium ion batteries. To study these interfaces, we present a novel approach for fabrication of electrochemically active nanobatteries using focused ion beams and their characterization by analytical electron microscopy. Morphological changes by scanning transmission electron microscopy imaging and correlated elemental concentration changes by electron energy loss spectroscopy mapping are presented. We provide first evidence of lithium accumulation at the anode/current collector (Si/Cu) and cathode/electrolyte (LixCoO2/LiPON) interfaces, which can be accounted for the irreversible capacity losses. Interdiffusion of elements at the Si/LiPON interface was also witnessed with a distinct contrast layer. These results highlight that the interfaces may limit the lithium transport significantly in solid-state batteries. Fabrication of electrochemically active nanobatteries also enables in situ electron microscopy observation of electrochemical phenomena in a variety of solid-state battery chemistries.

104Operando X-ray photoelectron spectroscopy of solid electrolyte interphase formation and evolution in Li2S-P2S5 solid-state electrolytesOpenAlex

Kevin N. Wood, K. Xerxes Steirer, Simon Hafner, et al.
O formation. The spatially non-uniform distribution of these phases, coupled with differences in their ionic conductivities, have important implications for the overall properties and performance of the solid-electrolyte interphase.

105Lithium Difluorophosphate Additive Engineering Enabling Stable Cathodic Interface for High‐Performance Sulfide‐Based All‐Solid‐State Lithium BatteryOpenAlex

Zhan Wu, Limao Du, Tianqi Yang, et al.
Coupling with high‐voltage oxide cathode is the key to achieve high‐energy density sulfide‐based all‐solid‐state lithium batteries. However, the complex interfacial issues including the space charge layer effect and undesirable side reaction between sulfide solid‐state electrolytes and oxide cathode materials are the main constraints on the development of high‐performance all‐solid‐state lithium batteries, which lead to the continuous decay of electrochemical performance. Herein, different from the complicated coating procedure, a LiPO 2 F 2 additive engineering was proposed to achieve high‐performance all‐solid‐state lithium batteries. With the introduction of LiPO 2 F 2 additive, a protective cathode–electrolyte interphase consisting of LiP x O y F z , LiF, and Li 3 PO 4 could be in situ formed to improve the interfacial stability between LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) and Li 5.5 PS 4.5 Cl 1.5 (LPSC). Benefiting from this, the NCM811/LPSC/Li all‐solid‐state lithium battery exhibited impressive cyclic stability with a capacity retention of 85.5% after 600 cycles (at 0.5 C). Diverse and comprehensive characterization, combined with finite element simulation and density functional theory calculation fully demonstrated the effective component, interfacial stabilization function and enhanced kinetic of LiPO 2 F 2 ‐derived cathode–electrolyte interphase. This work provides not only a feasible and effective method to stabilize the cathodic interface but also worthy insight into interfacial design for high‐performance all‐solid‐state lithium batteries.

106Synergistic Li6PS5Cl@Li3OCl composite electrolyte for high-performance all-solid-state lithium batteriesOpenAlex

Yuzhe Zhang, Haolong Chang, Aiguo Han, et al.
Li6PS5Cl is a highly wanted sulfide-solid-electrolyte (SSE) for developing all-solid-state lithium batteries, due to its high ionic conductivity, good processability and abundant compositional elements. However, its cyclability is poor because of harmful side reactions at the Li6PS5Cl/Li interface and growth of lithium dendrites inside Li6PS5Cl phase. Herein, we report a simple interface-engineering remedy to boost the electrochemical performance of Li6PS5Cl, by coating its surface with a Li-compatible electrolyte Li3OCl having low electronic conductivity. The obtained Li6PS5Cl@Li3OCl core@shell structure exhibits a synergistic effect. Consequently, compared with the bare Li6PS5Cl, this composite electrolyte exhibits great performance improvements: 1) In Li|electrolyte|Li symmetric cells, the critical current density at 30 °C gets increased from 0.6 mA cm−2 to 1.6 mA cm−2, and the lifetime gets prolonged from 320 h to 1400 h at the cycling current of 0.2 mA cm−2 or from 10 h to 900 h at the cycling current of 0.5 mA cm−2; 2) In Li|electrolyte|NCM721 full cells running at 30 °C, the cycling capacity at 0.2 C (or 0.5 C) gets enhanced by 20% (or from unfeasible to be feasible) for 100 cycles and the rate capability reaches up to 2 C from 0.2 C; and in full cells running at 60 °C, the cycling capacity is increased by 7% at 0.2 C and the rate capability is enhanced to 3.0 C from 0.5 C. The experimental studies and theoretical computations show that the performance enhancements are due to the confined electron penetration and suppressed lithium dendrites growth at the Li6PS5Cl@Li3OCl interface.

107Polymer Electrolyte Glue: A Universal Interfacial Modification Strategy for All-Solid-State Li BatteriesOpenAlex

Derui Dong, Bin Zhou, Yufei Sun, et al.
conductors with competitive ionic conductivity to those of liquid electrolytes have been reported. However, the incorporation of highly conductive solid electrolytes into the lithium-ion batteries is still very challenging mainly due to the high resistance existing at the solid-solid interfaces throughout the battery structure. Here, we demonstrated a universal interfacial modification strategy through coating a curable polymer-based glue electrolyte between the electrolyte and electrodes, aiming to address the poor solid-solid contact and thus decrease high interfacial resistance. The liquid glue exhibits both great wettability as well as chemical/electrochemical stability to most of the electrodes, and it can be easily solidified into a polymer electrolyte layer through a "post-curing" treatment. As a result, symmetric Li batteries with the glue modification exhibit much smaller impedance and enhanced stability upon plating/stripping cycles compared to the batteries without glue modification. The all-solid-state Li-S batteries with glue modification show significantly enhanced performances. The strategy of developing glue electrolytes to improve the electrode-electrolyte interface contact provides an alternative option for improving many other solid-state batteries.

108Tuning the Anode–Electrolyte Interface Chemistry for Garnet‐Based Solid‐State Li Metal BatteriesOpenAlex

Tao Deng, Xiao Ji, Yang Zhao, et al.
under ambient conditions due to the enhanced interfacial stability to the Li metal anode. The coated and infused LPO electrolytes not only improve the mechanical strength and Li-ion conductivity of the grain boundaries, but also form a stable Li-ion conductive but electron-insulating LPO-derived solid-electrolyte interphase between the Li metal and the GSE. Consequently, the growth of Li dendrites is eliminated and the direct reduction of the GSE by Li metal over a long cycle life is prevented. This interface engineering approach together with grain-boundary modification on GSEs represents a promising strategy to revolutionize the anode-electrolyte interface chemistry for SSLBs and provides a new design strategy for other types of solid-state batteries.

109A fast and low-cost interface modification method to achieve high-performance garnet-based solid-state lithium metal batteriesOpenAlex

Bing Zhao, Wencheng Ma, Bobo Li, et al.

110Polymer electrolytes and interfaces toward solid-state batteries: Recent advances and prospectsOpenAlex

Feng Wu, Kun Zhang, Yiran Liu, et al.

111Interfacial self-healing polymer electrolytes for long-cycle solid-state lithium-sulfur batteriesOpenAlex

Fei Pei, Lin Wu, Yi Zhang, et al.
Coupling high-capacity cathode and Li-anode with solid-state electrolyte has been demonstrated as an effective strategy for increasing the energy densities and safety of rechargeable batteries. However, the limited ion conductivity, the large interfacial resistance, and unconstrained Li-dendrite growth hinder the application of solid-state Li-metal batteries. Here, a poly(ether-urethane)-based solid-state polymer electrolyte with self-healing capability is designed to reduce the interfacial resistance and provides a high-performance solid-state Li-metal battery. With its dynamic covalent disulfide bonds and hydrogen bonds, the proposed solid-state polymer electrolyte exhibits excellent interfacial self-healing ability and maintains good interfacial contact. Full cells are assembled with the two integrated electrodes/electrolytes. As a result, the Li||Li symmetric cells exhibit stable long-term cycling for more than 6000 h, and the solid-state Li-S battery shows a prolonged cycling life of 700 cycles at 0.3 C. The use of ultrasound imaging technology shows that the interfacial contact of the integrated structure is much better than those of traditional laminated structure. This work provides an interesting interfacial dual-integrated strategy for designing high-performance solid-state Li-metal batteries.

112Li Distribution Heterogeneity in Solid Electrolyte Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub> upon Electrochemical Cycling Probed by <sup>7</sup>Li MRIOpenAlex

Po‐Hsiu Chien, Xuyong Feng, Mingxue Tang, et al.
Li MRI and the derived histograms reveal Li depletion from the electrode-electrolyte interfaces and increased heterogeneity of Li distribution upon electrochemical cycling. Significant Li loss at interfaces is mitigated via facile modification with a poly(ethylene oxide)/bis(trifluoromethane)sulfonimide Li salt thin film. This study demonstrates a powerful tool for noninvasively monitoring the Li distribution at the interfaces and in the bulk of all-solid-state batteries as well as a convenient strategy for improving interfacial stability.

113Recent advances in all-solid-state batteries for commercializationOpenAlex

Junghwan Sung, Junyoung Heo, Dong-Hee Kim, et al.
Challenges in the commercialization of all solid-state and next-generation batteries including strategies, key points, and application of solid-state batteries.

114Future Challenges to Address the Market Demands of All-Solid-State BatteriesOpenAlex

K.P. Abhilash, P. Nithyadharseni, P. Sivaraj, et al.