Tuning\nSolvation Behavior of Ester-Based Electrolytes\ntoward Highly Stable Lithium-Metal Batteries

Abstract

Metallic\nLi is the ultimate choice for the anode of lithium batteries.\nHowever, the adverse effect retards the commercialization of Li-metal\nbatteries (LMBs). Herein, by using Cu­(NO₃)₂ to\nregulate the solvation behavior of the ester-based electrolyte without\nfluoroethylene carbonate (FEC), the properties of Li|NCM811 are improved\nevidently. The solvation degree and oxidation stability of the electrolyte\nare increased. The solvated NO₃^– and\nmarginalized PF₆^– promote the formation\nof an inorganic-rich solid electrolyte interphase (SEI) film on the\nanode, effectively protecting the lithium metal. The voltage decay\nand the dissolution of transition metals in the Li|NCM811 cell are\nsignificantly suppressed. The cell exhibits a capacity retention as\nhigh as 95.73% after 600 cycles at room temperature and outstanding\ncycle performance for wide temperatures (0 and 50 °C). The cell\nalso shows impressive cycle performance even under rigorous conditions.\nOur research elucidates the role of Cu­(NO₃)₂ from the perspective of the solvation behavior and provides a new\nstrategy for the application of nitrates in ester-based electrolytes\nfor LMBs.