Mechanochemical synthesis of lithium ion conducting glasses and glass–ceramics in the system Li2S–P–S

Abstract

The Li2S–P–S glasses were prepared by mechanical milling from the mixture of Li2S and elemental phosphorus and sulfur. The conductivity of the glasses was 2.0×10−5 S cm−1 at room temperature. Raman spectroscopy revealed that the glasses mainly consisted of PS43− and Li+ ions, and partially contained homo bonds such as P–P and S–S bonds. Heat treatment of the glasses above the crystallization temperature produced glass–ceramics in which the crystal analogous to thio-LISICON with high conductivity was precipitated. The precipitation of the thio-LISICON analog enhanced the conductivity of the glasses, and the conductivity of the glass–ceramics was 3.9×10−4 S cm−1 at room temperature. The Li2S–P–S glass–ceramics contained mainly PS43− ions with a small amount of S–S bonds, and the amounts of the P–P and S–S homo bonds in the glass–ceramics were diminished by heat treatment than those in the glasses. The local structure of the Li2S–P–S glass–ceramics was similar to that of the Li2S–P2S5 glass–ceramics prepared from Li2S and P2S5 using as raw materials.