Improved Ionic Conductivity and Li Dendrite Suppression Capability toward LiPS-Based Solid Electrolytes Triggered by Nb and O Cosubstitution.

It is still a big challenge to simultaneously enhance the ionic conductivity, dendrite suppression capability, and interfacial compatibility of sulfide solid electrolytes. In this work, a novel LiPNbSO solid electrolyte is prepared via Nb and O cosubstitution of glass-ceramic LiPS. This sulfide-based electrolyte possesses a high ionic conductivity (3.59 mS cm) at 298 K, improved critical current density (1.16 mA cm), and excellent interfacial compatibility between the sulfide electrolyte and LiS active material. The improved electrochemical stability of the sulfide solid electrolyte against metallic lithium is attributed to the formation of Nb and LiO at the interface, which can induce uniform Li deposition and prevent further side reaction. The all-solid-state Li/LiS batteries based on this electrolyte exhibit remarkably enhanced cycling stability and rate performance.