In situ modified sulfide solid electrolyte enabling stable lithium metal batteries

With the advantages of high ionic conductivity and wide electrochemical window, sulfide-based solid electrolyte becomes a current research hotspot of all-solid-state lithium batteries. Nevertheless, severe interfacial problem between the sulfide electrolyte and lithium metal remains a great challenge, which can render a high interfacial resistance and hinder the transfer of lithium ions through interface, ultimately degrading the cycling performance. Furthermore, lithium dendrites easily form inside the electrolyte, thus accelerating the dendrite-induced shorting behavior of the battery. In this work, Li₂S layer is in-situ coated on the surface of the sulfide solid electrolyte Li₇P₃S₁₁ for highly stable lithium metal battery. The Li₂S layer can effectively prevent Li₇P₃S₁₁ from reacting with lithium metal. Meanwhile, the incorporation of the lithium sulfide can inhibit the generation and growth of internal lithium dendrites, thereby improving the cycling stability. The all-solid-state batteries based on the new designed electrolyte exhibit remarkably enhanced cycling stability. This work provides a simple and effective strategy to suppress lithium dendrite and promotes the practical application of sulfide-based all-solid-state batteries.