Improved Ionic Conductivity and Li Dendrite Suppression Capability toward Li7P3S11-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 Li7P2.88Nb0.12S10.7O0.3 solid electrolyte is prepared via Nb and O cosubstitution of glass-ceramic Li7P3S11. This sulfide-based electrolyte possesses a high ionic conductivity (3.59 mS cm–1) at 298 K, improved critical current density (1.16 mA cm–2), and excellent interfacial compatibility between the sulfide electrolyte and Li2S active material. The improved electrochemical stability of the sulfide solid electrolyte against metallic lithium is attributed to the formation of Nb and Li2O at the interface, which can induce uniform Li deposition and prevent further side reaction. The all-solid-state Li/Li2S batteries based on this electrolyte exhibit remarkably enhanced cycling stability and rate performance.