Y and Sb co-doped Li7La3Zr2O12 electrolyte for all solid-state lithium batteries

Li7La3Zr2O12 (LLZO) with high ionic conductivity and excellent chemical and electrochemical stability with metallic Li is considered to be one of the most promising candidates for solid-state batteries. In this work, Li6.925La3-xYxZr1.925Sb0.075O12 (0 <= x <= 0.1) garnets were prepared through solid-state reaction method, and effects of the co-dopant on the structure and ionic property are studied. The co-doping of Y3+ (0-0.075) and Sb5+ (0.075) accelerates the formation of cubic phase structure. Meanwhile, Li6.925La2.95Y0.05Zr1.925Sb0.075O12 (relative density similar to 95.1%) showed the highest total conductivity (3.20 x 10(-4) S/cm) and the lowest activation energy of 0.30 eV at 30 degrees C. Moreover, the high discharge capacity and capacity retention of solid-state battery of LiFePO4/Li6.925La2.95Y0.05Zr1.925Sb0.075O12/Li indicate that Y and Sb co-doped Li7La3Zr2O12 ceramic should be a promising electrolyte.

Automated summary

Co-doping of Y and Sb in Li6.925La2.95Y0.05Zr1.925Sb0.075O12 enhances the formation of cubic phase structure and results in the highest total conductivity and lowest activation energy. This co-doped ceramic shows promising potential as an electrolyte for solid-state batteries with high discharge capacity and capacity retention.