New lithium ion conducting glass-ceramics prepared from mechanochemical Li2S–P2S5 glasses
Amorphous solid electrolytes in the system Li 2 S-P 2 S 5 were prepared from a mixture of crystalline Li 2 S and P 2 S 5 using a mechanical milling technique at room temperature. In the composition range x≤87.5 of xLi 2 S(100-x)P 2 S 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 2 S.20P 2 S 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 7 PS 6 , Li 3 PS 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.