New lithium ion conducting glass-ceramics prepared from mechanochemical Li 2S–P 2S 5 glasses

Abstract

Amorphous solid electrolytes in the system Li 2S–P 2S 5 were prepared from a mixture of crystalline Li 2S and P 2S 5 using a mechanical milling technique at room temperature. In the composition range x≤87.5 of xLi 2S·(100− x)P 2S 5, conductivities of the glassy powders mechanically milled for 20 h were as high as 10 −4 S cm −1 at room temperature. The heat treatment of the 80Li 2S·20P 2S 5 glassy powders at around 220 °C produced dense glass-ceramics with high conductivity around 10 −3 S cm −1 at room temperature. The crystallization of conductive phases of Li 7PS 6, Li 3PS 4 and unknown crystals from the glass matrix and the decrease of grain boundaries by the softening of the glassy powders are simultaneously achieved at relatively low temperatures, around 220 °C.