A highly stable and conductive cerium‐doped Li₇P₃S₁₁ glass‐ceramic electrolyte for solid‐state lithium–sulfur batteries

Abstract

In this report, a facile wet chemical method using acetonitrile combined with thermal annealing was used to prepare Li2S‐P2S5 (LPS) based glass‐ceramic electrolytes with (1 wt%, 3 wt%, and 5 wt% Ce2S3) and without Ce2S3 doping. The crystal structure, ionic conductivity, and chemical stability of Li7P3S11 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 Li7P3S11 was observed at a temperature of 325°C. By incorporating 1 wt% Ce2S3 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 Li7P3S11 more chemically stable, compared to its original 70Li2S‐30P2S5 counterpart. According to Raman and X‐ray photoelectron spectroscopy analyses, cerium doping inhibits the decomposition of highly conductive P2S74‐ (pyro‐thiophosphate) to PS43− and P2S64−. Doped LPS has a greater crystallinity and more uniform microstructure than pure LPS, according to XRD, Raman spectroscopy, and scanning electron microscopy analysis. Consequently, Li7P2.9Ce0.1S11 electrolyte shows great potential as a solid‐state electrolyte for constructing high‐performance sulfide‐based all‐solid‐state batteries.