Lithium ion conducting solid electrolytes prepared from Li2S, elemental P and S

Glassy electrolyte of 80Li(2)S.20P(2)S(5) (mol%) was prepared by mechanical milling of Li2S and the mixture of elemental phosphorus and sulfur, which was mechanically milled in advance (two-step process). The glass showed relatively low conductivity of 3.9 x 10(-5) S cm(-1) at room temperature, while the glass-ceramic obtained by crystallization exhibited higher conductivity of 4.3 x 10(-4) S cm(-1) than the pristine glass. Raman spectroscopy revealed that the glass was mainly composed of the PS43- ions and slightly contained homo bonds such as P-P and S-S bonds. The mechanochemical synthesis using the two-step process was effective in reducing the homo bonds in the glassy electrolytes. The glass-ceramic, in which a highly ion-conductive thio-LISICON analog was precipitated, was mainly composed of the PS43- ions and very small amounts of S-S bonds. Cyclic voltammmetry demonstrated that the Li2S-P-S glass-ceramic had wide electrochemical window of 5 V. (c) 2006 Elsevier B.V. All rights reserved.