Here we report solid oxide cells with thin strontium- and magnesium-doped lanthanum gallate electrolytes that yield power densities of 1.06 W cm−2 at 550 °C and 0.81 W cm−2 at 500 °C when operated on humidified hydrogen and ambient air. Cost-effective ceramic processing and chemical solution impregnation methods were utilized, yielding a dual micron- and nano-scale architecture that is essential for achieving good low-temperature performance.