Development of 4V-Class Bulk-Type All-Solid-State Lithium Rechargeable Batteries by a Combined Use of Complex Hydride and Sulfide Electrolytes for Room Temperature Operation

Abstract

We have operated a 4V-class bulk-type, all-solid-state LiCoO₂/Li battery at room temperature. The battery consisted of a Li₄(BH₄)₃I complex hydride electrolyte as the electrolyte layer, and a 80Li₂S 20P₂S₅ sulfide glass as an electrolyte in the positive electrode layer. The assembled battery exhibited a 92 mAh g⁻¹ initial discharge capacity at 298 K and 0.1 C. The discharge capacity for the 20^th cycle remained as high as 83 mAh g⁻¹, corresponding to a capacity retention ratio of nearly 90%.