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.

Graphical abstractA new type of composite polymer electrolyte is prepared by using poly(ethylene oxide) segmented polysulfone copolymer and succinonitrile. It shows high mechanical strength in a wide temperature range and good electrochemical performance.Figure optionsDownload full-size imageDownload high-quality image (264 K)Download as PowerPoint slideHighlights► We first utilize PSF–PEO copolymers to prepare solid polymer electrolyte. ► This electrolyte shows superior mechanical properties in a wide temperature range. ► PSF–PEO35+LiTFSI+SN electrolyte has good compatibility toward Li electrode. ► Li/LiFePO4 cell using this electrolyte displays good electrochemical behavior.