A fluorinated branched polyether for PEO-based polymer electrolyte via thiol-Michael addition click reaction

Abstract

Polyethylene oxide (PEO) is considered as the most promising and widely studies polymer matrix. However, its practical application is limited for its low ionic conductivity at room temperature. Here, a novel fluorinated branched (2,2,2-Trifluoroethyl methacrylate (TFEMA)) ether polymer (PFP) was synthesized through thiol-Michael addition click reaction and blended with PEO to obtained PEO-based polymer electrolyte. The introduction of PFP could reduce the crystallinity and hinder the migration of anions, resulting in a double increase in ionic conductivity and lithium-ion transference number. More importantly, the symmetric Li/Li employing blended polymer shows stable cycle more than 1700 h and the Li/LiFePO₄ cell shows the superior performance of both cycling and rating at 60 °C. Even at lower temperature (28 °C), the Li/LiFePO₄ cell exhibits encouraging cycling performance with 88.6% capacity retention at 0.2C after 100 cycles. This study provides a novel strategy for structural design and synthesis progress of solid polymer electrolyte.