The developments, challenges, and prospects of solid-state Li-Se batteries

Li-chalcogen batteries with the high theoretical energy density have been received as one of most promising secondary lithium-ion batteries for next generation energy storage devices. Compared to solid-state Li-S batteries (S-LSBs) at the bottleneck of development, solid-state Li-Se batteries (S-LSeBs) have comparable volumetric energy density and fast reaction kinetics due to the higher density and electronic conductivity of Se, which furnishes a commendable opportunity to replace S-LSBs. Currently, many painstaking efforts have been paid in this territory, but S-LSeBs are still in early stage. Therefore, this review aims to offer a comprehensive overview of the existing studies to guide and facilitate their further development of S-LSeBs. Firstly, the components, working mechanism and primary challenges of S-LSeBs are elaborated. Secondly, we focus on the recent advances in various electrolyte systems and the construction of anode/cathode of S-LSeBs. Thirdly, a series of design parameters, including the electrolyte thickness, the loading of active material, the proportion of composite cathode, the N/P ratio and the number of bipolar stackings, are systematically analyzed to guide the designation of S-LSeBs with high energy density over 400 Wh kg-1 and even 500 Wh kg-1. Finally, the potential direction and future prospects in S-LSeBs are proposed.