Cathode performance of nanostructured La_1-aSr_aCo _1-bFe_bO_3-x on a Ce_0.8Sm _0.2O₂ electrolyte prepared by citrate-nitrate autocombustion

Nanostructured La1-a Sra Co1-b Feb O3-x (a=0.3 -0.5; b=0 -0.2) and Ce0.8 Sm0.2 O2 powders were successfully prepared by citrate-nitrate autocombustion synthesis and were characterized by scanning electron microscopy and X-ray diffraction analysis. Electrochemical impedance spectroscopy measurements on symmetric cells were performed to evaluate the applicability of La1-a Sra Co1-b Feb O3-x as a cathode material for intermediate temperature solid oxide fuel cells based on Sm doped-ceria electrolytes. Our results demonstrated that strontium has a positive effect while iron shows a slightly negative effect on the interfacial resistance. The effect of the electrode sintering temperature was investigated by varying the temperature from 850 to 1250°C, and the best sintering temperature was found to be 900°C. The best characteristics as cathode at intermediate operating temperatures were found for the composition with a=0.4 and the minimum iron doping, b=0.05; at 700°C, an area specific resistance of 0.13 cm2 was measured.