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

In this work, we report FeCo 2 O 4 - x Ce 0.8 Sm 0.2 O 1.9 ( 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 Ce 0.8 Sm 0.2 O 1.9 incorporation on physical and electrochemical properties . The obtained results indicate that the addition of Ce 0.8 Sm 0.2 O 1.9 to form FeCo 2 O 4 –Ce 0.8 Sm 0.2 O 1.9 composite material plays a key role in physical and electrochemical properties. Among all the components, the FeCo 2 O 4 –60Ce 0.8 Sm 0.2 O 1.9 composite cathode has the lowest polarization resistance of ∼0.094 Ω cm 2 at 800 °C in air, which is much smaller than that of the FeCo 2 O 4 cathode (4.18 Ω cm 2 ). In comparison with the FeCo 2 O 4 cathode, the FeCo 2 O 4 –60Ce 0.8 Sm 0.2 O 1.9 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 FeCo 2 O 4 –60Ce 0.8 Sm 0.2 O 1.9 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 FeCo 2 O 4 –60Ce 0.8 Sm 0.2 O 1.9 oxide has great potential to become a cathode material for solid oxide fuel cells.