A highly stable and conductive cerium‐doped Li ₇ P ₃ S ₁₁ glass‐ceramic electrolyte for solid‐state lithium–sulfur batteries

In this report, a facile wet chemical method using acetonitrile combined with thermal annealing was used to prepare Li 2 S‐P 2 S 5 (LPS) based glass‐ceramic electrolytes with (1 wt%, 3 wt%, and 5 wt% Ce 2 S 3 ) and without Ce 2 S 3 doping. The crystal structure, ionic conductivity, and chemical stability of Li 7 P 3 S 11 glass‐ceramic electrolytes were examined at varying temperatures (250–350°C). The results indicated that the highest ionic conductivity of 3.15 × 10 −4 S cm −1 for pure Li 7 P 3 S 11 was observed at a temperature of 325°C. By incorporating 1 wt% Ce 2 S 3 and subjecting it to a heat treatment at 250°C, the glass ceramic electrolyte attained a remarkable ionic conductivity of 7.7 × 10 −4 (S cm −1 ) at 25°C. Furthermore, it exhibited a stable and extensive electrochemical potential range, reaching up to 5 volts when compared to the Li/Li + reference electrode. By tuning the glass transition and crystallization temperature, cerium doping seems to make Li 7 P 3 S 11 more chemically stable, compared to its original 70Li 2 S‐30P 2 S 5 counterpart. According to Raman and X‐ray photoelectron spectroscopy analyses, cerium doping inhibits the decomposition of highly conductive P 2 S 7 4‐ (pyro‐thiophosphate) to PS 4 3− and P 2 S 6 4− . Doped LPS has a greater crystallinity and more uniform microstructure than pure LPS, according to XRD, Raman spectroscopy, and scanning electron microscopy analysis. Consequently, Li 7 P 2.9 Ce 0.1 S 11 electrolyte shows great potential as a solid‐state electrolyte for constructing high‐performance sulfide‐based all‐solid‐state batteries.