High performance Sm0.5Sr0.5CoO3–La0.8Sr0.2Ga0.8Mg0.15Co0.05O3 composite cathodes

High performance Sm0.5Sr0.5CoO3(SSC)–La0.8Sr0.2Ga0.8Mg0.15Co0.05O3 (LSGMC5) composite cathodes for intermediate temperature solid oxide fuel cells (ITSOFC) were prepared and characterized. The SSC powders were synthesized using the glycine–nitrate method and La0.8Sr0.2Ga0.8Mg0.15Co0.05O3(LSGMC5) powders were synthesized using the citrate method. The calcining temperature for the SSC and LSGMC5 powders had strong effect on the microstructure of the composite electrode and electrode/electrolyte interface, which affected the performance of the SSC-LSGMC5 electrode strongly. The electrode based on SSC calcined at 1223 K and LSGMC5 calcined at 1273 K exhibited the highest performance among the electrodes studied. The electrode resistance was about 0.07 Ω cm2, and the overpotential under 1 A cm−2 current density was as low as 0.077 V at 973 K in oxygen, which could be an ideal cathode for ITSOFC based on lanthanum gallate electrolytes.