Preparation of amorphous 75L2S·xP2S3·(25−x)P2S5 (mol%) solid electrolytes by a high-energy ball-milling process and their application for an all-solid-state lithium battery

Preparation of lithium ion conducting solid electrolytes in the composition 75Li2S·xP2S3·(25−x)P2S5 (mol%) was attempted by use of a high-energy ball-milling process at room temperature. Amorphous samples were obtained in the composition range of x=0 to x=5. In the samples with x ≥ 8.3, a crystalline Li2S phase was remained after the ball milling for 50 h. The lithium ion conductivity at 298 K of the amorphous samples was increased with an increase in x, and the amorphous sample with x=5 showed the highest lithium ion conductivity of 6.2×10−4 S·cm−1 at 298 K among the obtained samples. A laboratory-scale all-solid-state lithium battery using the amorphous sample with x=5 showed good discharge-charge performance at room temperature.