Evaluation of elastic modulus of Li2S–P2S5 glassy solid electrolyte by ultrasonic sound velocity measurement and compression test

Elastic modulus is an important factor of solid electrolytes for an all-solid-state battery as a next-generation battery. In this study, Young’s moduli of dense pellets of the Li2S–P2S5 glass solid electrolytes prepared by room temperature pressing and hot pressing were investigated. The Young’s moduli of Li2S–P2S5 hot-pressed pellets measured by ultrasonic sound velocity measurements were 18–25 GPa and those of cold-pressed pellets were about 14–17 GPa. The compression test was also done to determine Young’s modulus. The Young’s modulus of Li2S–P2S5 glasses increased with increasing the Li2S content in both hot press and cold press pellets. The Young’s moduli were lower than those of oxide based solid electrolytes.