Preparation and characterization of composite quasi-solid electrolytes composed of 75Li2S·25P2S5 glass and phosphate esters

Abstract

Mechanical properties and ionic conductivities of solid electrolytes are important factors influencing the performance of all-solid-state batteries. This study investigates composite quasi-solid electrolytes composed of Li2S–P2S5 glass and a phosphate ester, prepared via planetary ball milling, and the relative densities of the powder-compressed pellets, formed using the composite quasi-solid electrolytes. Dense pellets of the Li2S–P2S5 glass electrolyte are obtained via addition of phosphate esters; the relative densities increase from 90.6% to 93.1%, without the ionic conductivities decreasing, upon addition of a small quantity of tris (2, 2, 2-trifluoroethyl) phosphate to the Li3PS4 glass. The addition of small quantities of phosphate esters to sulfide solid electrolytes is effective in improving the formability of these solid electrolytes.