A novel solid composite polymer electrolyte based on poly(ethylene oxide) segmented polysulfone copolymers for rechargeable lithium batteries

It is a compelling challenge to develop solid polymer electrolyte membranes for rechargeable battery with both high ionic conductivity and superior mechanical performance. In this study, we first prepare a new type of all-solid-state composite polymer electrolyte from lithium bis-trifluoromethanesulphonimide (LiTFSI), succinonitrile (SN) and poly(ethylene oxide) segmented polysulfone copolymers (PSF–PEO) with various PEO contents in low molecular weight (Mn=1500 Da), which are synthesized by condensation polymerization. The optimized composite polymer electrolyte PSF–PEO35+LiTFSI+SN membrane exhibits a remarkable amorphous state; leading to its ionic conductivity of 1.6×10−4 S cm−1 at room temperature. Especially, the tensile strength of the PSF–PEO35+LiTFSI+SN electrolyte membrane is still more than 4.3 MPa at 80 °C, indicating its excellent mechanical property and high thermal stability in a wide temperature range. Li symmetric cell and Li/LiFePO4 cell with the above electrolyte display low voltage polarization and good rechargeability. The test results indicate that the solid PSF–PEO35+LiTFSI+SN composite electrolyte membrane is a promising candidate for future applications in rechargeable lithium batteries.