High-performance all-solid-state Li-Se batteries induced by sulfide electrolytes

All-solid-state Li-S batteries have attracted significant attention due to their high energy density and high safety. However, the insulating nature of S has limited the electrochemical performance of all-solid-state systems. Alternatively, Se, possessing orders of magnitude higher electronic conductivities, may be a promising cathode candidate but has been completely overlooked in all-solid-state battery systems. Herein, a feasible all-solid-state Li-Se battery is demonstrated using Se-Li3PS4-C as the cathode, Li3PS4 as the electrolyte, and an Li-Sn alloy as the anode. In addition to the high electronic conductivity (1 x 10(-3) S cm(-1)) of Se, a high Li+ conductivity of 1.4 x 10(-5) S cm(-1) across the Se-Li3PS4 interface can be achieved. The all-solid-state Li-Se cell shows a high reversible capacity of 652 mA h g(-1) (96% of theoretical capacity) and exhibits favorable capacity retention upon cycling. This work demonstrates the advantages of a Se cathode in all-solid-state batteries and provides new opportunities for improving the charge transfer of S cathodes in solid-state batteries.