Solid Polymer Electrolytes Based on Polysiloxane Crosslinked by Modified Natural Gallic Acid for All-Solid-State Lithium-Sulfur Battery Applications

Abstract

Solid polymer electrolytes (SPEs) based on polysiloxane having ion-conducting poly(ethylene oxide) (PEO) groups crosslinked with modified gallic acid from natural resources were prepared by thiol-ene click reaction for all-solid-state lithium-sulfur batteries. The effects of crosslinking density on thermal/mechanical and electrochemical properties were systematically studied. SPEs were found to be thermally and mechanically stable even at elevated temperature due to formation of stable crosslinked polymer network by modified gallic acid crosslinker. Furthermore, SPE based on 80 mol% of PEO group and 20 mol% of modified gallic acid crosslinker exhibited high ionic conductivity comparable to that of waxy polymer electrolyte having only the PEO group without crosslinking. All-solid-state lithium-sulfur battery was fabricated by preparing SPE integrated sulfur cathode and it is expected that SPE can act as mechanical and chemical barrier against dissolution of lithium polysulfides, resulting in excellent cycle performance at high temperature.