Understanding the role of interfaces in solid-state lithium-sulfur batteries

All-solid-state lithium-sulfur batteries (ASSLSBs) exhibit huge potential applications in electrical energy storage systems due to their unique advantages, such as low costs, safety and high energy density. However, the issues facing solid-state electrolyte (SSE)/electrode interfaces, including lithium dendrite growth, poor interfacial capability and large interfacial resistance, seriously hinder their commercial development. Furthermore, an insufficient fundamental understanding of the interfacial roles during cycling is also a significant challenge for designing and constructing high-performance ASSLSBs. This article provides an in-depth analysis of the origin and issues of SSE/electrode interfaces, summarizes various strategies for resolving these interfacial issues and highlights advanced analytical characterization techniques to effectively investigate the interfacial properties of these systems. Future possible research directions for developing high-performance ASSLSBs are also suggested. Overall, advanced in-situ characterization techniques, intelligent interfacial engineering and a deeper understanding of the interfacial properties will aid the realization of high-performance ASSLSBs.