Practical evaluation of energy densities for sulfide solid-state batteries

All-solid-state Lithium (ion) batteries (ASSLBs) have been widely accepted as the key technology for next-generation energy storage devices, for which sulfide solid electrolyte (SSE) is most promising due to its high ionic conductivity and good mechanical property. For the development of sulfide ASSLBs, their energy densities with different electrode systems at cell level should be calculated as first priority, to rule out exaggerated/misleading reports and enable dedicated solutions to specific material systems with clear energy-density targets/applications. Herein, we evaluate the gravimetric/volumetric energy densities of sulfide ASSBs with practical parameters in a commercialized pouch cell for 8 common cathode/anode systems. The typical spacial distribution modes of solid electrolyte (SE) in electrodes are all considered to further precisely evaluate their effects on energy densities. Results show that for LiCoO2/SSE (50 μm)/Li ASSLB, its gravimetric (volumetric) energy density ranges in 410–280 Wh kg−1 (820-560 Wh L−1), as active material content varies from 96.5 to 67.5 wt%. By providing calculation paradigms of energy densities with practical conditions and reasonable assumptions, this study aims to present an unambiguous understanding in energy density predictions of sulfide ASSBs with real-world conditions.