Rapid Desolvation and Anti-Reduction Electrolyte Enables High-Performance Lithium Metal Batteries

Lithium metal batteries (LMBs) have attracted widespread attention due to their potential for high-energy-density storage applications. However, the sluggish kinetics of traditional carbonate electrolytes at the electrode interface and severe side reactions between electrodes and electrolytes impedes the practical implementation of LMBs. Herein, we design a fast desolvation and anti-reduction electrolyte to achieve high-performance LMBs by tuning the solvation structure of Li+. The incorporation of bis(trifluoromethanesulfonyl)imide (TFSI−) and difluorophosphate (DFP−) anions into the solvation structure of Li+ mitigates the reactivity of the electrolyte with Li metal, promoting the anti-reduction capability of the electrolyte. In addition, the interaction between Li+ and solvent molecules as well as anions is weakened, which reduces the desolvation energy of Li+. Furthermore, the proposed anions can be preferentially sacrificed to form an inorganic-rich cathode electrolyte interphase (CEI), thereby inhibiting the oxidative decomposition of the electrolyte and the dissolution of transition metal (TM) elements. Therefore, the reversibility of the Li anode is improved to 97.8% and the Li||NCM622 cell exhibits a capacity retention of 78.3% after 250 cycles at 1 C. Even at a high loading or 3 C rate, the Li||NCM622 cells also demonstrate exceptional electrochemical performance.