Liu Qing, Meng Tao, Yu Le, Guo Songtao, Hu Yunhuan, Liu Zhifang, Hu Xianluo
State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
Small Methods. 2022 Jul;6(7):e2200380. doi: 10.1002/smtd.202200380. Epub 2022 Jun 1.
Battery safety is vital to the application of lithium-ion batteries (LIBs), especially for high energy density cells applied in electric vehicles. As an anode material with high theoretical capacity and natural abundance, Si has received extensive attention for LIBs. However, it suffers from severe electrode pulverization during cycling due to large volume changes and an unstable solid electrolyte interphase (SEI), resulting in accelerated capacity fading and even safety hazards. Therefore, safe and long-term cycling of Si-based anodes, especially under high-temperature cycling, is highly challenging for state-of-the-art high-energy LIBs. The thermal behavior of SEI is crucial for a high safety battery as the decomposition of SEI is the first step in thermal runaway. Here, highly reversible and thermotolerant microsized Si anodes for safe LIBs are demonstrated. Comprehensive electrochemical/mechanical/thermochemical behaviors of the SEI are systematically investigated. The rational design of robust SEI endows the Si-based cells with long-term durability at elevated temperatures and superior thermal safety. This work paves the way for designing industrial-scale, low-cost, microsized Si anodes with applications in next-generation LIBs with high energy densities and high safety.
电池安全对于锂离子电池（LIBs）的应用至关重要，尤其是对于应用于电动汽车的高能量密度电池而言。作为一种具有高理论容量和天然丰度的负极材料，硅在锂离子电池领域受到了广泛关注。然而，由于体积变化大以及固体电解质界面（SEI）不稳定，硅在循环过程中会遭受严重的电极粉化，导致容量加速衰减甚至产生安全隐患。因此，对于先进的高能量锂离子电池来说，实现硅基负极的安全且长期循环，尤其是在高温循环条件下，极具挑战性。SEI的热行为对于高安全电池至关重要，因为SEI的分解是热失控的第一步。在此，展示了用于安全锂离子电池的具有高度可逆性和耐热性的微米级硅负极。系统地研究了SEI的综合电化学/机械/热化学行为。对坚固SEI的合理设计赋予了硅基电池在高温下的长期耐久性和卓越的热安全性。这项工作为设计工业规模、低成本、微米级硅负极铺平了道路，这些负极可应用于具有高能量密度和高安全性的下一代锂离子电池。
