Effects of Methyl Acetate as a Co-Solvent in Carbonate-Based Electrolytes for Improved Lithium Metal Batteries

In lithium metal batteries (LMBs), electrolytescomposed of salts and organic solvents play a significant role in transporting Li+ ions and creating the surface film on Li-metal anodes. Herein, the effect of methyl acetate(MA) as a co-solvent is reported, which enables the facilitated Li+ transport and formation of a robust solid electrolyteinterphase (SEI) on the Li-metal anode. The symmetrical Li// Licell tests show remarkable cycle stability of MA-based electrolytesat 3 mA/cm2 without obvious voltage fluctuation. At 5 mA/cm2, the Li// Licells in MA-based electrolytescan still run up to 110 h with lower overpotential, compared to the cell cycled with MA-free electrolytes. Furthermore, the LMBs consisting of the Lianode and LiNi0.8Co0.15Al0.05O2 (NCA) cathode deliver the high capacity (∼200 mA h/g), good cycling stability up to 300 cycles, excellent rate capability (10 C), and low self-dischargingrates (8.5%) with MA-based electrolytes. Especially, the capacity of the Li//NCA cells with MA30 electr...