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. [Display omitted] •A hybrid solid electrolyte of Li2S coated Li7P3S11 is synthetized via a facile method.•The increased ionic conductivity and enhanced compatibility against lithium are achieved.•The symmetrical cell based on Li2S@LPS can be stably charge/discharged for 400 h.•All solid-state batteries show superior electrochemical performance.