LiNO3 additive in PVDF-based electrolyte enhanced interface stability in lithium metal batteries

Solid polymer electrolytes (SPEs) with high ionic conductivity and electrochemical stability are crucial for the potential practical applications of solid-state lithium metal batteries. In SPEs based on polyvinylidene fluoride (PVDF), the addition of N , N -dimethylformamide (DMF) enhances ionic conductivity but reduces the electrochemical stable window. This work proposes a strategy to improve the stability of PVDF-based SPEs with high ionic conductivities using LiNO 3 additive. By adding 5% of LiNO 3 (comparing to the weight of LiTFSI lithium salt), the ionic conductivity of prepared PVDF-based SPEs achieves up to 10 −4 S cm −1 at 30 ℃. The assembled Li|SPE|NCM811 cells with the LiNO 3 -modified SPE film as separator maintained a capacity retention rate of 93.0% after 200 electrochemistry cycles induced at a current density of 0.5 C. The influence of LiNO 3 in the interface resistance, Li-ionic transfer number, solid electrolyte interface phase, and electrochemistry performance of LIBs is investigated.