Complementary Push–Pull Effects Induced Solvation Structure Enables Low-Temperature Li-Metal Batteries

Lithium-metal batteries suffer from sluggish charge-transfer kinetics and unstable solid electrolyte interphase (SEI) layers under low temperatures, invariably leading to significant performance degradation. Herein, we propose a complementary “push and pull” electrolyte design strategy to controllably regulate the Li+ solvation structure. The pull factor is designed to enhance the interaction between Li+ and weakly solvating solvents, considering the electrostatic potential (ESP), Li+–solvent binding energy, solvent–solvent interactions, and F-donating ability. Furthermore, inorganic Li salt with a high Li+–anion binding energy is designed as a push factor to lower the Li+ desolvation barrier and weaken the destructive effects of the pull factor on the SEI, forming a high-ionic-conductive and stable SEI. As a result, stable Li plating/stripping with high Coulombic efficiencies of 99.4% and 98.5% are achieved under −20 and −40 °C, respectively, and the Li/LiFePO4 full cell can retain 73% of room-temperature capacity under −20 °C. These results demonstrate an effective electrolyte strategy for low-temperature Li-metal batteries.