Protection of Li metal anode by surface-coating of PVDF thin film to enhance the cycling performance of Li batteries

Lithium metal, the ideal anode material for next-generation high-energy batteries, suffers from the severe safety problem of Li dendrites. Herein, we report a simple approach to effectively maintain the morphology of Li-metal anode and enhance the cycling performance of Li batteries by surface coating of a porous polyvinylidene fluoride (PVDF) thin film. In symmetrical cells testing, the cells with the Li@PVDF electrode display stable cycling performance more than 1300 h (650 cycles) at the current density of 0.5 mA/cm² with a stripping/plating capacity of 0.5 mAh/cm². The results with full cells employing Li@PVDF anode and LiFePO₄ cathode show a good cycling ability with a capacity retention of 80.0% after 500 cycles at 4 C and an excellent rate capability with a high capacity of 78.4 mA h/g even at a high rate of 10 C.