Wang Hansen, Yan Xiaolin, Zhang Rupeng, Sun Juanjuan, Feng Fuxiang, Li Haoran, Liang Jinding, Wang Yuchun, Ye Guangzhou, Luo Xiaonan, Huang Shengyuan, Wan Pan, Hung Samantha T, Ye Fangjun, Chen Fangyun, Wu Erxiao, Zhou Jinfei, Ulissi Ulderico, Ge Xiaoming, Liu Chengyong, Xu Bo, Liu Na, Ouyang Chuying
21C LAB, Contemporary Amperex Technology Co., Limited, Ningde, China.
Department of Physics, Jiangxi Normal University, Nanchang, China.
Nat Nanotechnol. 2025 May 28. doi: 10.1038/s41565-025-01935-y.
Unwanted side reactions occurring at electrode|electrolyte interfaces significantly impact the cycling life of lithium metal batteries. However, a comprehensive view that rationalizes these interfacial reactions and assesses them both qualitatively and quantitatively is not yet established. Here, by combining multiple analytical techniques, we systematically investigate the interfacial reactions in lithium metal batteries containing ether-based non-aqueous electrolyte solutions. We quantitatively monitor various nanoscale-driven processes such as the reduction and oxidation pathways of lithium salt and organic solvents, the formation of various solid-electrolyte interphase species, the gas generation within the cell and the cross-talk processes between the electrodes. We demonstrate that the consumption of lithium ions owing to the continuous decomposition of the lithium bis(fluorosulfonyl)imide salt, which dominates the interfacial reactions, results in ion depletion during the cell discharge and battery failure. On the basis of these findings, we propose an electrolyte formulation in which lithium bis(fluorosulfonyl)imide content is maximized without compromising dynamic viscosity and bulk ionic conductivity, aiming for long-cycling battery performance. Following this strategy, we assemble and test Li (20 μm thickness)||LiNiMnCoO (17.1 mg cm of active material) single-layer stack pouch cells in lean electrolyte conditions (that is, 2.1 g Ah), which can effectively sustain 483 charge (0.2 C or 28 mA)/discharge (1 C or 140 mA) cycles at 25 °C demonstrating a discharge capacity retention of about 77%.
电极|电解质界面处发生的不良副反应会显著影响锂金属电池的循环寿命。然而，目前尚未建立一个能够合理解释这些界面反应并对其进行定性和定量评估的全面观点。在此，通过结合多种分析技术，我们系统地研究了含有醚基非水电解质溶液的锂金属电池中的界面反应。我们定量监测了各种纳米级驱动的过程，如锂盐和有机溶剂的还原与氧化途径、各种固体电解质界面物种的形成、电池内的气体生成以及电极之间的串扰过程。我们证明，由于双（氟磺酰）亚胺锂盐的持续分解主导了界面反应，锂离子的消耗导致电池放电过程中的离子耗尽和电池失效。基于这些发现，我们提出了一种电解质配方，其中双（氟磺酰）亚胺锂的含量在不影响动态粘度和本体离子电导率的情况下最大化，旨在实现长循环电池性能。按照这一策略，我们在贫电解质条件下（即2.1 g Ah）组装并测试了Li（厚度为20μm）||LiNiMnCoO（活性材料为17.1 mg cm）单层叠片软包电池，该电池在25°C下能够有效地维持483次充电（0.2 C或28 mA）/放电（1 C或140 mA）循环，放电容量保持率约为77%。
