Ion-compensation regime between electrolyte and cathode to prepare advanced lithium metal batteries

Abstract

To improve the ion conduction ability and interfacial issues between electrolyte and electrode and provide a high safety and long lifespan for polymer electrolyte-based lithium metal batteries, gel polymer electrolytes with excellent thermal and electrochemical stability are prepared via polyacrylic salt-catalyzed radical polymerization. The gradient design of polyacrylic complex impels the in-situ formation of gel polymer electrolytes, robust solid electrolyte interphase and cathode electrolyte interface layer, delivering an excellent lithium platting-stripping property (1000 h, 0.1 mA cm−2) and a long-term cycling with 80.1% capacity retention (600 cycles, 1C) for the as-assembled lithium symmetric and Li/LiFePO4 cells, respectively. Moreover, the manual ion-compensation between the bulk electrolyte and the cathode enhances the diffusion of lithium ion with a high diffusion coefficient of 3.47 × 10−13 cm2 s−1, and slows down the capacity decay with a high discharge capacity of 121.0 mA h/g at 5C. This method provides a direction for improving the electrolyte–electrode compatibility and designing advanced lithium metal batteries.