Wang Qianqian, Wang Tairan, Zhang Pu, Yang Deshuai, Zhang Cuili, Wang Lang, Lu Shengbo, Liu Tracy Chenmin, Qi Shihan, Huang Weiguo, Liu Jingjing, Zhu Guannan, Fan Jun
Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, 999077, China.
Yuanlin Tech Co., Ltd, Hong Kong, 999077, China.
Small. 2025 Aug;21(31):e2503340. doi: 10.1002/smll.202503340. Epub 2025 Jun 4.
Lithium-ion transport across the solid electrolyte interphase (SEI) is a key procedure in charging which determines the performance and stability of lithium-ion batteries (LIBs). However, an atomic-level understanding of the overall transport process from electrolyte through SEI remains elusive, particularly regarding the thermodynamic and kinetic parameters that govern this cross-interface phenomenon. In this study, molecular dynamics (MD) simulations are employed to systematically investigate the complete Li-ion transport progress, encompassing the electrolyte, organic/inorganic SEI components, and two critical interfaces: electrolyte/organic SEI and organic SEI/inorganic SEI. The results indicate that Li ions in the organic SEI retain either full or partial solvation shells. Free energy profiles reveal that the highest energy barrier emerges at the organic-inorganic SEI interface due to the complete desolvation of Li ions and structural differences between the organic and inorganic SEI layers. By constructing a comprehensive free energy landscape for Li-ion transport, this study offers valuable insights into the relationship between SEI composition, structure, and interfacial dynamics.
锂离子穿过固体电解质界面（SEI）的传输是充电过程中的关键步骤，它决定了锂离子电池（LIBs）的性能和稳定性。然而，对于从电解质通过SEI的整个传输过程，在原子层面上仍缺乏了解，特别是关于控制这种跨界面现象的热力学和动力学参数。在本研究中，采用分子动力学（MD）模拟系统地研究了完整的锂离子传输过程，包括电解质、有机/无机SEI成分以及两个关键界面：电解质/有机SEI和有机SEI/无机SEI。结果表明，有机SEI中的锂离子保留了完整或部分溶剂化壳层。自由能分布表明，由于锂离子的完全去溶剂化以及有机和无机SEI层之间的结构差异，在有机-无机SEI界面处出现了最高的能垒。通过构建用于锂离子传输的综合自由能图景，本研究为SEI组成、结构和界面动力学之间的关系提供了有价值的见解。
