Li2S–Li2O–P2S5 solid electrolyte for all-solid-state lithium batteries

Various compositions of Li2S–Li2O–P2S5 solid electrolytes were prepared by planetary ball milling and systematically investigated. Structural analysis by X-ray diffraction (XRD) and Raman spectroscopy showed phase changes in the electrolyte corresponding to changes in conductivity. All-solid-state LiCoO2/Li cells were tested by constant–current–constant–voltage (CCCV) charge–discharge cycling at a current density of 50 μA cm− 2 between 2.5 and 4.3 V (vs. Li/Li+). In spite of reduced conductivity from introducing oxide species into a sulfide based electrolyte, increased cycle stability is observed for increased concentrations of Li2O in the electrolyte.