Conductivity of strontium- and lithium-doped-lanthanum orthogallate (La_0.9Sr_0.1Ga_1-yLi_yO_{3- δ}; y = 0.05 and 0.10) synthesized via metal nitrate-glycine gel route

Strontium- and magnesium-doped-lanthanum orthogallate have emerged as promising alternative solid electrolytes for solid-oxide fuel cells in the intermediate-temperature regime. In accordance with the theoretical consideration, doping by a monovalent ion at the B-site is envisaged to increase the defect concentration and enhance the oxide ion conductivity. With this aim, strontium- and lithium-doped-lanthanum orthogallate formulations (La_0.9Sr_0.1Ga_1-yLi_yO_{3- δ}; y = 0.05 and 0.10) were synthesized via soft-chemistry route of metal nitrate-glycine combustion. Systematic phase and microstructural evolution as a function of processing temperature was followed by X-ray diffraction and scanning electron microscopy of the calcined and sintered samples. Electrical characterization on the sintered sample by the 4-point DC and AC impedance measurements in the temperature range of 550-850 °C showed that Li-doping at B-site in LaGaO₃ yielded conductivity higher than that of yttria-stabilized zirconia, but somewhat inferior to the Mg-doped analogs.