Electrical and electrochemical properties of Li 2S–P 2S 5–P 2O 5 glass–ceramic electrolytes

Abstract

The electrical and electrochemical properties of the Li 2S–P 2S 5–P 2O 5 glass–ceramic electrolytes were investigated. The 80Li 2S·(20 − x)P 2S 5· xP 2O 5 (mol%) glass–ceramics were prepared by a mechanical milling and a subsequent heat treatment. The 80Li 2S·19P 2S 5·1P 2O 5 glass–ceramic showed the high lithium ion conductivity of 7.4 × 10 −4 S cm −1 at room temperature and the low activation energy of 34 kJ mol −1 for conduction. The addition of a small amount of P 2O 5 to the Li 2S–P 2S 5 sulfide system lowered the electronic conductivity and enhanced the electrochemical stability of the glass–ceramic electrolytes. All-solid-state In/LiCoO 2 cells with the 80Li 2S·19P 2S 5·1P 2O 5 glass–ceramic as a solid electrolyte worked as lithium secondary batteries at room temperature. The cells maintained high discharge capacity of about 100 mAh g −1 for 10 cycles.