Breaking Solvation Dominance Effect Enabled by Ion–Dipole Interaction Toward Long-Spanlife Silicon Oxide Anodes in Lithium-Ion Batteries
Shengwei Dong, Lingfeng Shi, Shenglu Geng, Yanbin Ning, Cong Kang, Yan Zhang, Ziwei Liu, Jiaming Zhu, Zhuomin Qiang, Lin Zhou, Geping Yin, Dalong Li, Tiansheng Mu, Shuaifeng Lou
Abstract
Abstract Micrometer-sized silicon oxide (SiO) anodes encounter challenges in large-scale applications due to significant volume expansion during the alloy/de-alloy process. Herein, an innovative deep eutectic electrolyte derived from succinonitrile is introduced to enhance the cycling stability of SiO anodes. Density functional theory calculations validate a robust ion–dipole interaction between lithium ions (Li + ) and succinonitrile (SN). The cosolvent fluoroethylene carbonate (FEC) optimizes the Li + solvation structure in the SN-based electrolyte with its weakly solvating ability. Molecular dynamics simulations investigate the regulating mechanism of ion–dipole and cation–anion interaction. The unique Li + solvation structure, enriched with FEC and TFSI − , facilitates the formation of an inorganic–organic composite solid electrolyte interphase on SiO anodes. Micro-CT further detects the inhibiting effect on the SiO volume expansion. As a result, the SiO|LiCoO 2 full cells exhibit excellent electrochemical performance in deep eutectic-based electrolytes. This work presents an effective strategy for extending the cycle life of SiO anodes by designing a new SN-based deep eutectic electrolyte.