Gel Polymer Electrolyte Membranes Consisted of Solvate Ionic Liquid and Crosslinked Network Polymers Bearing Different Main Chains: Fabrication and Lithium Battery Application

Polymer electrolyte membranes have been proposed as alternatives to conventional liquid electrolytes to improve the performance and stability of lithium-ion batteries. For past decades, wide varieties of polymer electrolyte membranes have been reported; however, most of the membranes contain critical issues with their ion conductivity and/or stability for practical battery applications. In this study, we aim to develop gel polymer electrolyte membranes with high ion conductivity and sufficient stability by combining solvate ionic liquid and three types of crosslinked network polymers synthesized from multifunctional monomers with vinyl and thiol groups. One of the obtained gel polymer electrolyte membranes, poly(TTT-PEMP)/G4-LiTFSI, showed high ion conductivity close to 10^-3 S cm^-1 at room temperature and superior electrochemical stability (oxidation stability: >5.0V vs. Li/Li⁺). The lithium metal batteries using the gel polymer electrolyte membranes achieved continuous stable charge/discharge cycles, promising future lithium metal batteries operated at high voltage for the long term.