Single‐Ion Gel Polymer Electrolyte Based on Poly(ether sulfone) for High‐Performance Lithium‐Ion Batteries

Abstract In this study, a poly(ether sulfone) is grafted with lithium 3‐chloroproanesulfonyl(trifluoromethanesulfonyl)imide (LiCPSI) through Williamson reaction to obtain a poly(ether sulfone) single‐ion polymer (PES‐LiCPSI). PES‐LiCPSI and poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) are mixed and then soaked with plasticizer (EC/PC = 1:1, v/v) to obtain a novel single‐ion gel polymer electrolyte (PES‐GPE). Its ionic conductivity of the prepared electrolyte is 7.1 × 10 −5 S cm −1 at 20 °C, and the tensile strength is increased to 50.5 MPa. The lithium‐ion transfer number is up to 0.92, which should be helpful to inhibit the formation of lithium dendrites effectively. LiFePO 4 /PES‐GPE/Li half cells assembled with PES‐GPE possesses outstanding cycle performance and rate performance. It releases a specific capacity of 128 mAh g −1 at 0.2 C, and the capacity retention rate is as high as 97% after 370 cycles. The excellent properties of PES‐GPE demonstrate its massive capacity in high‐power and long‐cycle lithium‐ion batteries.