Investigation of Mg2Â +, Sc3Â + and Zn2Â + doping effects on densification and ionic conductivity of low-temperature sintered Li7La3Zr2O12 garnets

Garnet-type solid electrolytes Li7La3Zr2 − xMg2xO12, Li7La3Zr2 − 0.75xScxO12 and Li7 − 2xZnxLa3Zr2O12 with x = 0, 0.025, 0.05 and 0.1 were synthesized at 1075 °C by using the traditional solid-state reaction method. It is found that substitution of Mg2 + and Sc3 + for Zr4 + is more effective in improving the Li7La3Zr2O12 (LLZ)'s densification and ionic conductivity than the substitution of Zn2 + for Li+. As a result, the highest room-temperature total conductivity and the lowest activation energy are obtained in LLZ-Mg-2x with x = 0.05, being 0.291 mS/cm at 293 K and 0.254 eV, respectively.