Thermal and electrical properties of rapidly quenched Li2S-SiS2-Li2O-P2O5 oxysulfide glasses

We have systematically investigated the thermal and electrical properties o f (1 - y)[xLi(2)S .(100 - x)SiS2]. y[xLi(2)O .(100 - x)P2O5] (45 less than or equal to x less than or equal to 67; y = 0, 0.05, 0.20) oxysulfide glass es in the wide range of lithium ion concentration. These oxysulfide glasses with y = 0.05 exhibited high Tc-Tg values, which is a measure of the glass stability against crystallization, and high ion conductivities at room tem perature in the middle range of lithium ion concentration around x = 55 mol %. In the same composition range, large amounts of silicon atoms coordinate d with both sulfur and oxygen atoms, i.e. SiOnS4-n (n = 1, 2, 3) tetrahedra l units, were observed by Si-29 MAS-NMR measurements. The presence of such unique structural units brought about the high glass stability and high ion conductivity of the glasses with y = 0.05. (C) 1998 Published by Elsevier Science B.V. All rights reserved.