Yuan Yufei, Wang Dan-Dong, Zhang Zhengyang, Bang Ki-Taek, Wang Rui, Chen Huanhuan, Wang Yanming, Kim Yoonseob
Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong SAR, China.
University of Michigan - Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
ACS Appl Mater Interfaces. 2024 Aug 28;16(34):44957-44966. doi: 10.1021/acsami.4c10123. Epub 2024 Aug 13.
Ideal solid electrolytes for lithium (Li) metal batteries should conduct Li rapidly with low activation energy, exhibit a high Li transference number, form a stable interface with the Li anode, and be electrochemically stable. However, the lack of solid electrolytes that meet all of these criteria has remained a considerable bottleneck in the advancement of lithium metal batteries. In this study, we present a design strategy combining all of those requirements in a balanced manner to realize quasi-solid-state electrolyte-enabled Li metal batteries (LMBs). We prepared Li-coordinated triptycene-based ionic porous organic polymers (Li@iPOPs). The Li@iPOPs with imidazolates and phenoxides exhibited a high conductivity of 4.38 mS cm at room temperature, a low activation energy of 0.627 eV, a high Li transference number of 0.95, a stable electrochemical window of up to 4.4 V, excellent compatibility with Li metal electrodes, and high stability during Li deposition/stripping cycles. The high performance is attributed to charge delocalization in the backbone, mimicking the concept of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), which facilitates the diffusion of coordinated Li through the porous space of the triptycene-based iPOPs. In addition, Li metal batteries assembled using Li@Trp-Im-O-POPs as quasi-solid-state electrolytes and a LiFePO cathode showed an initial capacity of 114 mAh g and 86.7% retention up to 200 cycles.
用于锂金属电池的理想固体电解质应能以低活化能快速传导锂离子，具有高锂离子迁移数，与锂负极形成稳定界面，并具有电化学稳定性。然而，缺乏满足所有这些标准的固体电解质仍然是锂金属电池发展的一个重大瓶颈。在本研究中，我们提出了一种设计策略，以平衡的方式结合所有这些要求，以实现基于准固态电解质的锂金属电池（LMBs）。我们制备了锂配位的三蝶烯基离子型多孔有机聚合物（Li@iPOPs）。含有咪唑盐和苯氧化物的Li@iPOPs在室温下表现出4.38 mS cm的高电导率、0.627 eV的低活化能、0.95的高锂离子迁移数、高达4.4 V的稳定电化学窗口、与锂金属电极的优异兼容性以及在锂沉积/剥离循环过程中的高稳定性。这种高性能归因于主链中的电荷离域，这模仿了双（三氟甲磺酰）亚胺锂（LiTFSI）的概念，促进了配位锂通过三蝶烯基iPOPs的多孔空间扩散。此外，使用Li@Trp-Im-O-POPs作为准固态电解质和LiFePO正极组装的锂金属电池，初始容量为114 mAh g，在200次循环后保持率为86.7%。
