An electrochemically stable homogeneous glassy electrolyte formed at room temperature for all-solid-state sodium batteries.

Chi, Xiaowei; Zhang, Ye; Hao, Fang; Kmiec, Steven; Dong, Hui; Xu, Rong; Zhao, Kejie; Ai, Qing et al. · Nat Commun · 2022

basic_science · Level V

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Abstract

All-solid-state sodium batteries (ASSSBs) are promising candidates for grid-scale energy storage. However, there are no commercialized ASSSBs yet, in part due to the lack of a low-cost, simple-to-fabricate solid electrolyte (SE) with electrochemical stability towards Na metal. In this work, we report a family of oxysulfide glass SEs (Na<sub>3</sub>PS<sub>4-x</sub>O<sub>x</sub>, where 0 < x ≤ 0.60) that not only exhibit the highest critical current density among all Na-ion conducting sulfide-based SEs, but also enable high-performance ambient-temperature sodium-sulfur batteries. By forming bridging oxygen units, the Na<sub>3</sub>PS<sub>4-x</sub>O<sub>x</sub> SEs undergo pressure-induced sintering at room temperature, resulting in a fully homogeneous glass structure with robust mechanical properties. Furthermore, the self-passivating solid electrolyte interphase at the Na|SE interface is critical for interface stabilization and reversible Na plating and stripping. The new structural and compositional design strategies presented here provide a new paradigm in the development of safe, low-cost, energy-dense, and long-lifetime ASSSBs.