Temperature-Adaptive Fluorine in Electrolyte for Lithium–Metal Batteries at Low Temperatures
Yao Li, Yimeng Huang, Yimeng Huang, Xue Han, Jieli Wu, Huyan Shen, Shitong Wang, Shuicen Ding, Shenmin Zhu, Bing Han, Yunhui Huang, Yunhui Huang, Di Zhang, Weijiang Xue
Abstract
Li-metal batteries (LMBs) are heavily constrained at low temperatures due to increased ion desolvation and transportation barriers. Here, we report a weakly solvating sulfonamide-based electrolyte that features a temperature-sensitive local chemical environment of the fluorine atoms in the sulfonamide molecules at low temperatures. The reactivity of the sulfonamide with Li-metal is further tailored by the adaptive fluorine chemistry at low temperatures, promoting the formation of more conductive LiF x components in the solid-electrolyte interphase. Benefiting from these characteristics, our electrolyte enables high Li-metal reversibility and delivers a high discharge capacity of 164.4 mAh g –1 at −30 °C (197.9 mAh g –1 at 25 °C) with a high capacity retention of 83.0% after 180 cycles at −30 °C in a 4.6-V-class Li||NMC622 battery, significantly outperforming the carbonate-based electrolyte. These results highlight the critical role of electrolyte design in practical LMBs under extreme conditions.