Compatibility of Li7La3Zr2O12 Solid Electrolyte to All-Solid-State Battery Using Li Metal Anode

Electrochemical properties of Li7La3Zr2O12 (LLZ) were investigated to reveal its availability as a solid electrolyte for all-solid-state rechargeable batteries with a Li metal anode. After calcination at 1230 degrees C, a well-sintered LLZ pellet with a garnet-like structure was obtained, and its conductivity was 1.8 X 10(-4) S cm(-1) at room temperature. The cyclic voltammogram of the Li/LLZ/Li cell showed that the dissolution and deposition reactions of lithium occurred reversibly without any reaction with LLZ. This indicates that a Li metal anode can be applied for an LLZ system. A full cell composed of a LiCoO2/LLZ/Li configuration was also operated successfully at expected voltage estimated from the redox potential of Li metal and LiCoO2. Simultaneously, an irreversible behavior was observed at the first discharge and charge cycle due to an interfacial problem between LiCoO2 and LLZ. The discharge capacity of the full cell was 15 mu A h cm(-2). These results reveal that LLZ is available for all-solid-state lithium batteries. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3474232] All rights reserved.