Improved room temperature ionic conductivity of Ta and Ca doped Li7La3Zr2O12 via a modified solution method

Ta and Ca doped Li7La3Zr2O12 is synthesized via a modified solution method without producing toxic NOx. Li7 − x + yCayLa3-yZr2 − xTaxO12 series with x range from 0 to 2 and y range from 0 to 0.05 are prepared and their ionic conductivities are found to be greatly enhanced by doping Ta and Ca to a certain amount. The optimized amount of Ta doped in Li7 − xLa3Zr2 − xTaxO12 is found to be x = 0.6, corresponding to a total ionic conductivity of 1.95 × 10− 4 S cm− 1. When further doped with Ca, a synergetic effect from Ta and Ca is observed and a high ionic conductivity of 2.84 × 10− 4 S cm− 1 is achieved in Li6.45Ca0.05La2.95Ta0.6Zr1.4O12. The simple solution method proposed in this work is considered to be potentially applied as a general methodology for synthesizing metal doped Li7La3Zr2O12.