Characteristics of the Li2O–Li2S–P2S5 glasses synthesized by the two-step mechanical milling

Sulfide solid electrolytes have high ion conductivities of 10− 4 to 10− 2 S cm− 1 at room temperature. However, sulfide electrolytes, which are hydrolyzed in air, generate H2S gas. In this study, an addition of Li2O to the 70Li2S·30P2S5 (mol%) glass and synthesis procedures of the sulfide glasses were examined to suppress H2S gas generation. The addition of Li2O decreased H2S gas generation from the glass electrolytes. Moreover, the two-step synthesis, in which glasses were prepared by the reaction of Li2O and the 70Li2S·30P2S5 glass prepared in advance, was extremely effective in suppressing H2S gas generation from the sulfide glass electrolytes. The Li2O–Li2S–P2S5 glass electrolytes prepared by the two-step synthesis showed relatively high conductivity of more than 10− 4 S cm− 1 at room temperature.

► The addition of Li2O to the 70Li2S·30P2S5 glass decreased H2S gas generation in air.
► The two-step synthesis was very effective in suppressing H2S gas generation.
► The addition of Li2O decreased conductivities of the sulfide glasses.
► The Li2O–Li2S–P2S5 glasses showed high conductivity of over 10− 4 S cm− 1 at 25 °C.