A fluorinated polycarbonate based all solid state polymer electrolyte for lithium metal batteries

Poly(ethylene oxide) (PEO) is a promising matrix for solid polymer electrolyte, but its inferior mechanical strength and relative low oxidation stability especially at elevated temperatures hamper its further applications. A novel fluorinated polycarbonate polymer of poly(2,2,3,3-tetrafluoro butyl carbonate) with cyano ends (cPTFBC) was synthesized for the first time and was composited with PEO based electrolyte by physical blending to resolve the above issues. The addition of cPTFBC can effectively enhance the mechanical strength at elevated temperature. In addition, the as-prepared PEO-cPTFBC based electrolyte shows an enlarged electrochemical window up to 4.7 V at 60 °C and a high Li ion transference number (0.33). More importantly, the PEO-cPTFBC based all solid state polymer electrolyte presents excellent compatibility with lithium metal and improved LiCoO₂/Li battery performance compared with PEO based electrolyte. These outstanding performance of the cPTFBC based electrolyte make it promising as solid polymer electrolyte for lithium metal batteries.