Formation of Li2S–P2S5 Solid Electrolyte from N-Methylformamide Solution

Li2S–P2S5 solid electrolyte (SE) powders were successfully reprecipitated from a liquid phase. Powders of 80Li2S·20P2S5 (mol %) SE originally prepared by mechanical milling were dissolved in N-methylformamide (NMF) and a homogeneous solution was obtained. The NMF solution was dried at 150 °C for 3 h under vacuum to obtain precipitates. The main structural unit in the obtained powder was PS43−. The crystalline phase of the powders was confirmed to be Li3PS4, and ionic conductivity was 2.6 × 10−6 S cm−1.