Structure and properties of the 70Li2S · (30 − x)P2S5 · xP2O5 oxysulfide glasses and glass–ceramics

The 70Li2S · (30 − x)P2S5 · xP2O5 (mol%) oxysulfide glasses were prepared by the melt quenching method. The glasses were prepared in the composition range 0 ≦ x ≦ 10. The glass–ceramics were prepared by heating the glasses over crystallization temperatures. The POnS3−n (n = 1–3) oxysulfide units were produced in the glasses and glass–ceramics by partial substituting P2O5 for P2S5. In particular, the P2OS64− unit would be produced by substituting a small amount of P2O5 for P2S5. The oxygen atoms were incorporated into the Li7P3S11 crystal structure because the diffraction peaks of the oxysulfide glass–ceramic shifted to the higher angle side. The glass–ceramic with 3 mol% of P2O5 exhibited the highest conductivity of 3.0 × 10−3 S cm−1 and the lowest activation energy for conduction of 16 kJ mol−1. The P2OS64− dimer units in the oxygen-incorporated Li7P3S11 crystal would improve conductive behavior of the Li2S–P2S5 glass–ceramics.