Solvent-Free Method Prepared a Sandwich-like Nanofibrous Membrane-Reinforced Polymer Electrolyte for High-Performance All-Solid-State Lithium Batteries

Solid polymer electrolytes (SPEs) with the advantages of high safety, low volatility, and the ability to suppress Li dendrites are highly desirable to be used in next generation high-safety and high-energy lithium-ion batteries. The exploration of SPEs with superior comprehensive properties has received extensive attention for high-performance all-solid-state batteries (ASSBs). Herein, a sandwich-like nanofibrous membrane-reinforced poly-caprolaclone diol and trimethyl phosphate (TMP) composite polymer electrolyte (CPE) has been designed by a facile “solvent-free” solution-casting method. Specifically, the flame-retardant TMP is employed as a plasticizer, which can improve the ionic conductivity effectively. The as-prepared solid electrolyte exhibits superior comprehensive performance in terms of high ionic conductivity, wide electrochemical window, good compatibility with lithium metal, and superior thermal stability. Furthermore, the assembled Li//LiFePO4 ASSBs with this solid CPE show outstanding cycling stability and high average discharge capacity at room temperature (30 °C). Undoubtedly, our study provides a new facile method and a qualified solid electrolyte material for next generation high-performance ASSBs.