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

Abstract

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 ~ 95.1%) showed the highest total conductivity (3.20 × 10−4 S/cm) and the lowest activation energy of 0.30 eV at 30 °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.