Stable Li Plating/Stripping in LiPF6-Cyclic Ether-Based Electrolytes

Abstract

Lithium metal is regarded as the ideal anode material for rechargeable batteries due to its exceptionally high theoretical capacity and low redox potential. Electrolytes combining imide salts and ethers have been extensively studied for their high reduction stability and ability to form robust protective films on Li-metal surfaces. Despite these advantages, concerns over safety and possible corrosion of battery components may severely limit industrial adoption. A major breakthrough would be the utilization of the well-established LiPF6 salt; however, its chemical instability and tendency to polymerize ether solvents present challenges. Herein, we report LiPF6/ether-based electrolytes that effectively suppress ether polymerization and form highly functional inorganic–organic bilayer films on Li. Consequently, a Coulombic efficiency of 99.5%, which is comparable to those of state-of-the-art imide-based systems, was achieved without using fluorinated solvents or additives. This marks a step forward in advancing LiPF6-based electrolytes for future rechargeable batteries.