Substituent effects of Ba2+ for Sm3+ on the structure and electrochemical performances of Sm0.5Sr0.5Co0.8Fe0.2O3−δ cathode for intermediate temperature solid oxide fuel cells

► A novel series of perovskite-type cathode materials Sm1-xBaxSr0.5Co0.8Fe0.2O3−δ (0 ≤ x ≤ 0.2) for solid state oxide fuel cells are prepared by a citric-nitrate process. ► Among the series of the samples, the highest conductivity was observed for Sm0.45Ba0.05Sr0.5Co0.8Fe0.2 O3−δ to be 1250 Scm−1 in air at 300 °C. ► The partial substitution of Ba for Sm site obviously enhanced the cathode materials. ► The cathode with the composition x = 0.2 exhibits the lowest area specific resistance, which is 0.032 Ωcm2 at 750 °C and 0.056 Ωcm2 at 700 °C. ► The cell with the composition x = 0.20 gives the maximum power density of 1030 mW cm−2 at 650 °C.