Solvation Regulation via Hydrogen Bonding to Mitigate Al Current Collector Corrosion for High‐Voltage Li‐Ion Batteries
Xinran Zhang, Xubing Dong, Xinyang Yue, Jingyu Gao, Zhangqin Shi, Jijiang Liu, Yongteng Dong, Yuanmao Chen, Mingming Fang, Honggang Yu, Zheng Liang
Abstract
Abstract The exceptional thermal stability and conductivity of lithium bis(fluorosulfonyl)imide (LiFSI) have made it a preferred salt for lithium‐ion batteries (LIBs). However, the corrosion of aluminum (Al) current collectors by LiFSI at low potentials (3.8 V vs Li/Li + ) poses a persistent challenge, hindering the application of LiFSI in 4 V‐class LIBs. Herein, 2,2,2‐trifluoroethyl methanesulfonate (TFMS) is proposed as a versatile co‐solvent to address the issue of Al current collector corrosion. It is demonstrated that incorporating TFMS into a conventional LiFSI‐based carbonate electrolyte can precisely tailor the Li + solvation structure by hydrogen bonding interactions with dimethyl carbonate (DMC) solvent. This weakens the coordination between DMC and Li + while increasing the participation of FSI − anions in the primary solvation shell, effectively suppressing the Al current collector caused by free FSI − anions attacking. Furthermore, TFMS and FSI − synergically induce the formation of an inorganic‐rich and compact cathode electrolyte interphase, significantly avoiding undesired side reactions. As a result, the TFMS‐electrolyte enables 1.2 Ah‐graphite||NCM811 (LiNi 0.8 Co 0.1 Mn 0.1 O 2 ) pouch‐cells to achieve 89.9% capacity retention with high average Coulombic efficiency of >99.9% for 200 cycles at a cut‐off voltage of 4.4 V, opening up opportunities for the development of advanced high‐voltage LIBs.