Development of 4 V-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 4 V class bulk type, all solid state LiCoO 2 /Li battery at room temperature. The composition consisted of a Li 4 (BH 4 ) 3 I complex hydride electrolyte for the electrolyte layer, and a 80Li 2 S 20P 2 S 5 sulfide glass for an electrolyte in the positive electrode layer. The battery assembled 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.