Processing Strategies to Improve Cell-Level Energy Density of Metal Sulfide Electrolyte-Based All-Solid-State Li Metal Batteries and Beyond

All-solid-state Li metal batteries (ASLBs) have the potential to surpass the energy density of commercial Li ion batteries and improve safety. However, most reported ASLBs deliver unsatisfactory cell-level energy densities, which are significantly affected by cell configuration. Therefore, for the first time, this Review summarized the processing of ASLBs toward cell-level high energy, with a focus on using sulfide solid-state electrolytes (SEs). We comprehensively analyzed the effects of the cathode, electrolyte, and Li metal anode on the energy density. Different strategies for the fabrication of thick cathode, thin electrolyte, and thin Li metal were systematically introduced, and their corresponding merits and challenges were summarized. In addition, the architectural design of ASLBs was discussed. Furthermore, we covered the most recent developments for other promising electrolytes. Finally, perspectives on the design of high-energy ASLBs toward practical applications were introduced.