Latest progresses and the application of various electrolytes in high-performance solid-state lithium-sulfur batteries

With the emergence of some solid electrolytes (SSEs) with high ionic conductivity being comparable to liquid electrolytes, solid-state lithium-sulfur batteries (SSLSBs) have been widely regarded as one of the most promising candidates for the next generation of power generation energy storage batteries, and have been extensively researched. Though many fundamental and technological issues still need to be resolved to develop commercially viable technologies, SSLSBs using SSEs are expected to address the present limitations and achieve high energy and power density while improving safety, which is very attractive to large-scale energy storage systems. SSLSBs have been developed for many years. However, there are few systematic discussions related to the working mechanism of action of various electrolytes in SSLSBs and the defects and the corresponding solutions of various electrolytes. To fill this gap, it is very meaningful to review the recent progress of SSEs in SSLSBs. In this review, we comprehensively investigate and summarize the application of SSEs in LSBs to determine the differences which still exist between current progresses and real-world requirements, and comprehensively describe the mechanism of action of SSLSBs, including lithium-ion transport, interfacial contact, and catalytic conversion mechanisms. More importantly, the selection of solid electrolyte materials and the novel design of structures are reviewed and the properties of various SSEs are elucidated. Finally, the prospects and possible future research directions of SSLSBs including designing high electronic/ionic conductivity for cathodes, optimizing electrolytes and developing novel electrolytes with excellent properties, improving electrode/electrolyte interface stability and enhancing interfacial dynamics between electrolyte and anode, using more advanced test equipment and characterization techniques to analyze conduction mechanism of Li+ in SSEs are presented. It is hoped that this review can arouse people's attention and enlighten the development of functional materials and novel structures of SSEs in the next step.