Tuning Solvation Behavior of Ester-Based Electrolytes toward Highly Stable Lithium-Metal Batteries

Metallic Li is the ultimate choice for the anode of lithium batteries. However, the adverse effect retards the commercialization of Li-metal batteries (LMBs). Herein, by using Cu(NO3)(2) to regulate the solvation behavior of the ester-based electrolyte without fluoroethylene carbonate (FEC), the properties of Li vertical bar NCM811 are improved evidently. The solvation degree and oxidation stability of the electrolyte are increased. The solvated NO3- and marginalized PF6- promote the formation of an inorganic-rich solid electrolyte interphase (SEI) film on the anode, effectively protecting the lithium metal. The voltage decay and the dissolution of transition metals in the Li vertical bar NCM811 cell are significantly suppressed. The cell exhibits a capacity retention as high as 95.73% after 600 cycles at room temperature and outstanding cycle performance for wide temperatures (0 and 50 degrees C). The cell also shows impressive cycle performance even under rigorous conditions. Our research elucidates the role of Cu(NO3)(2) from the perspective of the solvation behavior and provides a new strategy for the application of nitrates in ester-based electrolytes for LMBs.