Low-Entropy and Fast-Li⁺-Conducting Electrolyte With Cascade Reaction-Induced Robust Interphase for Fast-Charging Lithium Metal Batteries

Lithium metal is considered the most promising next-generation anode, while its fast-charging application is hindered by the problems of dendrite growth and side reactions. Herein, a low-entropy electrolyte with cascade reaction-induced stable interphase and fast Li⁺ transport kinetics is proposed to provide excellent fast-charging performance of lithium metal batteries. In this electrolyte with an extremely simple formula, only two co-solvents with a lithium salt are used without any other additives. Fast lithium transport and desolvation kinetics are maintained, owing to the solvents’ low viscosity and weak interaction with lithium. Particularly, the intermediate products of lithium salt can further promote rapid defluorination of the F-containing solvent to form LiF, constructing a LiF-rich interphase. Fast Li⁺ transport kinetics and robust interphase enable the fast-cycling performance of lithium metal anodes. The Li||Li symmetric cell can even withstand a high current density of 10 mA cm⁻². Good cycling stability under fast charging is also achieved with a capacity of 123 mAh g⁻¹ maintained with a capacity retention rate reaching 90% after 200 cycles at a charging rate of 6C. Our results demonstrate a simple yet effective electrolyte design strategy facilitating the fast cycling of lithium metal batteries.