A single ion polymer electrolyte via copolymerization of lithium (4-Styrenesulfonyl)(Trifluoromethanesulfonyl)imide and allyl Poly(Aryl ether Ketone) enables safe lithium ion batteries

Abstract

Given its capacity to suppress concentration polarization in lithium-ion batteries (LIBs), single-ion polymer electrolytes (SIPEs) have been considered a substitute for the traditional dual-ion electrolyte. However, SIPEs still have challenges such as low ion conductivity. Meanwhile, gel polymer electrolytes (GPEs) have high ionic conductivity and compatibility with electrodes, but are limited by concentration polarization. In this study, a novel poly(aryl ether ketone) (PAEK50) single-ion polymer (PAEK-LiSTFSI) was prepared via the copolymerization of lithium (4-styrenesulfonyl)(trifluoromethanesulfonyl)imide (LiSTFSI) and allyl poly(aryl ether ketone). The obtained PAEK-LiSTFSI was compounded with poly(ethylene oxide) and then immersed in EC/PC to obtain poly(aryl ether ketone) single-ion gel polymer electrolyte (PAEK-SIGPE). The tensile strength and elongation at break of PAEK-SIPE reached 21.4 MPa and 116.7 %, respectively. PAEK-SIGPE exhibited a high ionic conductivity of 7.8 × 10-5 S cm−1 at 30 °C and Li+ transference number of 0.95, which effectively inhibited the growth of lithium dendrites. The LiFePO4(LFP)/PAEK-SIGPE/Li half-cell possessed excellent cycle and rate performance. The discharge capacity of the battery reached 140 mAh g−1, and the capacity retention rate was as high as 95 % at 0.2C even after 400 cycles. These results indicated that the novel PAEK-SIGPE can be applied to next-generation LIBs.