Preparation of Li2S–P2S5 Amorphous Solid Electrolytes by Mechanical Milling

Abstract
Amorphous solid electrolytes in the Li2S–P2S5 system were prepared successfully from a mixture of crystalline Li2S and P2S5, using a mechanical milling technique. The amorphous‐forming region was extended to higher Li2S compositions by mechanical milling, compared with melt quenching. The pelletized samples of the 75Li2S·25P2S5 (on a mole‐percent basis) amorphous powders obtained by mechanical milling for 20 h exhibited high conductivity (2 × 10−4 S/cm at room temperature) and an activation energy for conduction of 34 kJ/mol. The lithium‐ion transport number of the amorphous powders was almost unity.