Interface issues between cathode and electrolyte in sulfide-based all-solid-state lithium batteries and improvement strategies of interface performance through cathode modification

Sulfide electrolyte-based all-solid-state lithium batteries (ASSLB) are heralded as a cornerstone for next-generation energy storage solutions, distinguished by their exceptional ionic conductivity, superior energy density, and enhanced safety features. Nonetheless, the ascendancy of sulfide-based ASSLB in augmenting energy density and elongating cycle life is curtailed by the suboptimal solid-solid interfacial contact and the compromised chemical/electrochemical stability of both the cathode and the sulfide solid electrolyte (SSE). This review dissects the quintessential challenges at the cathode-SSE interface, elucidating the underlying mechanisms contributing to elevated interfacial resistance, the formation of space charge layers, and interfacial compatibility dilemmas. It addresses the primary challenges at the cathode-SSE interface, highlighting the mechanisms behind increased interfacial resistance, chemical/electrochemical instability, and poor interfacial compatibility. It systematically explores strategies to improve the interface, including microstructure regulation, coating cathode, synthesis modification, and other treatments. Finally, it summarizes the development prospects and improvement methods of sulfide-based ASSLB.