Electrochemical performance evaluation of FeCo2O4 spinel composite cathode for solid oxide fuel cells

In this work, we report FeCo2O4-xCe0.8Sm0.2O1.9 (x = 0, 30, 40, 50, 60, 70 wt%), catalyst/electrolyte composite oxides, as cathode materials for application in solid oxide fuel cells. Herein a systematic investigation represents the effect of Ce0.8Sm0.2O1.9 incorporation on physical and electrochemical properties. The obtained results indicate that the addition of Ce0.8Sm0.2O1.9 to form FeCo2O4–Ce0.8Sm0.2O1.9 composite material plays a key role in physical and electrochemical properties. Among all the components, the FeCo2O4–60Ce0.8Sm0.2O1.9 composite cathode has the lowest polarization resistance of ∼0.094 Ω cm2 at 800 °C in air, which is much smaller than that of the FeCo2O4 cathode (4.18 Ω cm2). In comparison with the FeCo2O4 cathode, the FeCo2O4–60Ce0.8Sm0.2O1.9 composite cathode has a better electrocatalytic activity and a larger power density of 397 mWcm−2 based an electrolyte-supported single-cell configuration at 800 °C. The oxygen partial pressure dependence studies indicate that rate limiting steps of the FeCo2O4–60Ce0.8Sm0.2O1.9 composite cathode are the adsorption process of the molecular oxygen on the electrode surface and the charge-transfer process. In consequence of these superior properties, it is reasonable to believe that the FeCo2O4–60Ce0.8Sm0.2O1.9 oxide has great potential to become a cathode material for solid oxide fuel cells.