Investigation of the doping effects of Sr-Ta on the Ionic Conductivity of Garnet Li7La3Zr2O12 Solid Electrolyte

Abstract: A solid electrolyte having the ionic conductivity comparable to that of conventional liquid electrolyte can be used in All Solid State Batteries (ASSB's). The series Li6.75+xLa3-xSrxZr1.75Ta0.25O12 (x = 0 to 0.20) was synthesized to improve the ionic conductivity of garnet Li7La3Zr2O12 (LLZO). The structural, physical and morphological investigations have been carried out for all the synthesized samples using X ray diffraction, density measurement and scanning electron microscopy respectively. The results of electrochemical analysis showed that the maximum room temperature ionic conductivity of 3.5 x 10-4 S/cm and minimum activation energy of 0.29 eV is achieved by the 0.05 Sr ceramic sample sintered at 1050^oC. The DC conductivity measurement confirmed the dominance of ionic conduction in the prepared ceramic samples. The highest ionic conductivity with the minimum activation energy makes the 0.05 Sr ceramic sample a suitable choice as solid electrolyte for All Solid State Lithium Ion Batteries (ASSLIB's).