Study of structural, electrical and electrochemical properties of La0.7Sr1.3Co1−xFexO4 (x = 0, 0.1, 0.3, 0.5) Ruddlesden-Popper oxides as promising cathode for intermediate solid oxide fuel cells

In this research, different properties of La0.7Sr1.3Co1−xFexO4 (x = 0, 0.1, 0.3, 0.5) Ruddlesden-Popper (RP) oxides have been investigated as cathode materials to be used in intermediate solid oxide fuel cells. The cathode powders were successfully synthesized via a modified sol-gel route. The structural properties, lattice dynamics, and morphology of the synthesized powders were studied using x-ray diffraction (XRD) technique, Fourier transform infrared (FTIR) spectroscopy, and field emission scanning electron microscopy (FE-SEM). Electrical conductivity measurements showed that all sintered ceramics had semiconducting behavior in the temperature range of 30–800 °C. It was found that Fe substitution in Co sites led to decreasing the electrical conductivity but improved the oxygen reduction reaction activity of La0.7Sr1.3Co1−xFexO4-CGO symmetrical cell. Electrochemical impedance and distribution of relaxation time (DRT) analyses indicated that the area-specific polarization resistance (ASRp) decreased by Fe doping. The results revealed that Fe doping in La0.7Sr1.3CoO4 improves the electrochemical performance of the cathodic symmetrical cell and can be the promising cathode candidates to be used in intermediate solid oxide fuel cells.