Enabling Long-Life All-Solid-State Sodium Metal Batteries via in situ Construction of a Stable Solid Electrolyte Interphase

Abstract

Suppressing the interface deterioration and sodium dendrites growth is crucial for achieving long-life polyethylene oxide (PEO)-based all-solid-state sodium metal batteries. Herein, we systematically screen Sb₂S₃ for use as a PEO-based solid-state electrolyte (PSE) additive through theoretical calculations, and in situ construct a highly stable solid electrolyte interphase (SEI) enriched with Na₂S and Na₃Sb. This SEI, characterized by its low reduction reaction activity, high ionic conductivity, and strong Na affinity, significantly inhibits interfacial side reactions, accelerates ion transport, and facilitates smooth Na⁺ deposition. Moreover, the incorporation of Sb₂S₃ effectively enhances the mechanical robustness, ionic transference number, and ionic conductivity of the composite solid-state electrolyte film (Sb₂S₃@PSE), thereby mitigating the sodium dendrites formation. Consequently, remarkable electrochemical performances for the Sb₂S₃@PSE symmetric battery (achieving 5200 h at 0.1 mA cm⁻², 520 times longer than that of pristine PSE), and the Na₃V₂(PO₄)₃|Sb₂S₃@PSE|Na full battery with high-capacity retention of 91% after 1000 cycles, are demonstrated. This work, which emphasizes the in situ construction of a stable SEI, provides significant guidance to suppress interface degradation for long-life solid-state metal batteries.