Improving the Electrochemical Performance of NCM811 ∥ SiO/Gr Pouch Cells by Interface Modification with Anhydride Electrolyte Additives

Although LiNi0.8Co0.1Mn0.1O2 (NCM811) has been widely used in lithium-ion batteries (LIBs) as cathode materials, the high content of nickel typically leads to performance deterioration and other safety issues due to the catalytic decomposition of electrolyte. Herein, we propose a strategy to improve the stability of electrolyte by adopting anhydride-based additives with benzene group (e.g., 6FDA, FPA, and PSA). The theoretical calculation, electrochemical test, and structural characterization indicate that the addition of PSA enables NCM811 to better cycling performance at high, ambient, and low temperatures for pouch cells with SiO/graphite as the anode owing to its higher reduction potential in comparison with that of 6FDA and FPA.