Two-step sintering of sulfide solid electrolyte with improved electrochemical properties for all-solid-state lithium batteries

All-solid-state batteries are considered as a promising energy storage system thanks to the high energy density and intrinsic safety. Sulfide solid electrolytes, a key component, are of interest owing to their high ionic conductivity and wide electrochemical windows. However, it remains a great challenge to simultaneously improve the ionic conductivity and the ability to inhibit lithium dendrites. Here, we report a strategy to obtain sulfide solid electrolyte with excellent interfacial compatibility and the high ionic conductivity via two-step sintering. The obtained electrolyte possesses excellent interfacial compatibility with lithium metal (>1000 h) and improved critical current density (1.05 mA cm⁻²). Meanwhile, the all-solid-state batteries deliver a high discharge capacity of 160 mA h g⁻¹ with excellent stability of 90.4% after 100 cycles at 0.1C at room temperature. This study provides a novel and effective strategy for tuning the properties of sulfide electrolyte and promotes the practical application in sulfide-based all-solid-state batteries.