Preparation of amorphous solid electrolytes in the system Li2S–SiS2–Li4SiO4 by mechanical milling

Amorphous solid electrolytes in the system Li2S–SiS2–Li4SiO4 were successfully prepared from a mixture of Li2S, SiS2 and Li4SiO4 crystals using a mechanical milling technique at room temperature. In the composition range 0≤x≤5 of (100−x)(0.6Li2S·0.4SiS2)·xLi4SiO4, conductivities of the oxysulfide powders mechanically milled for 20 h were as high as 10−4 S cm−1 at room temperature, which are comparable to the values of the corresponding composition of melt-quenched glasses. As the period of mechanical milling treatment was increased from 0 to 20 h, the structure of milled powders became similar to that of the glasses prepared by melt quenching. Such a structure change brought about a large conductivity increase in the resultant powders from 10−9 to 10−4 S cm−1.