Intrinsic-safe polymer electrolyte enabling fast kinetics by accelerated dissociation and transport of Li-ion

Sluggish Li + ion transference kinetics and high flammability strictly hinder the practical application of lithium batteries based on solid-state polymer electrolytes (SPEs). Herein, guided by theoretical calculation, a modified organic flame retardant synthesized by blending diphenyl phosphoryl chloride and resveratrol is designed, named as DPPR and displays superior compatibility with polyethylene oxide (PEO) by hydrogen bonds. Thus, the as-constructed versatile electrolyte system (P-DPPR) can improve mechanical, flame-retardant, and migration kinetics properties of PEO simultaneously. With P-DPPR electrolyte, the Li//Li cell operates 1000 h at 0.1 cm −1 , DPPR can greatly decrease activation energy from 0.31 eV to 0.16, Li + transference number of DPPR is 0.76, the LiFePO 4 //Li cell can work from −10 to 60 °C and achieves high-capacity retention rate of 97.2 % after 100 cycles at 25 °C. As revealed by in-situ tests and simulation, the fast ion conductivity can be ascribed to the synergistic effect from promoted dissociation of LiTFSI by π-π interaction, and the accelerated delivery by P O sites in P-DPPR. This work fabricates a composite SPE with high stability, fast kinetics, and safety capabilities, offering a novel perspective for the design of intrinsically safe batteries.