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

Li 7 La 3 Zr 2 O 12 (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, Li 6.925 La 3-x Y x Zr 1.925 Sb 0.075 O 12 (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 Y 3+ (0–0.075) and Sb 5+ (0.075) accelerates the formation of cubic phase structure. Meanwhile, Li 6.925 La 2.95 Y 0.05 Zr 1.925 Sb 0.075 O 12 (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 LiFePO 4 /Li 6.925 La 2.95 Y 0.05 Zr 1.925 Sb 0.075 O 12 /Li indicate that Y and Sb co-doped Li 7 La 3 Zr 2 O 12 ceramic should be a promising electrolyte.