Mechanochemical Synthesis of New Amorphous Materials of 60Li ₂ S·40SiS ₂ with High Lithium Ion Conductivity

New amorphous materials were mechanochemically synthesized by use of crystalline starting materials of Li 2 S and SiS 2 . The conductivity of a mechanochemically prepared sample of 60Li 2 S40SiS 2 (mol%) after a milling for 20 h was around 10 ‐4 Scm ‐1 at room temperature. This conductivity was comparable to that of the corresponding glassy powders prepared by twin‐roller rapid quenching of melt and then pulverizing. The transport number of lithium ions in the mechanochemically prepared sample was nearly unity. Mechanochemical synthesis is a promising way to produce new solid electrolytes for solid‐state lithium secondary batteries.