The comparative study of doping Cu and Fe on the cathodic properties of La0.7Sr1.3CoO4 layered perovskite compound: To be used in IT-SOFC

Abstract

In this research, the effect of doping Cu and Fe on the properties of La0.7Sr1.3CoO4 as cathode for using in intermediate solid oxide fuel cells were studied. The x-ray diffraction patterns indicated that La0.7Sr1.3Co (1−x) (Fe/Cu)x O4 (x = 0, 0.1, 0.2 and 0.3) synthesized powders are tetragonal with I4/mmm space group. Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) revealed that oxygen vacancies were created easily in La0.7Sr1.3Co1−xCuxO4 synthesized powders while oxygen over-stoichiometry was observed in La0.7Sr1.3Co1−xFexO4 compounds. The temperature dependence of electrical conductivity showed the semiconducting behavior in all samples at the temperature range of 30–800 °C. Among the synthesized specimens, the maximum electrical conductivity was found in Cu doped samples. In order to study the electrochemical properties of the synthesized powders, electrochemical impedance spectroscopy (EIS) was used in which the cathodic processes were determined using distribution of the relaxation time (DRT) analysis. The results showed that, the polarization area-specific resistance (ASRp) decreased from 1.2 Ωcm2 for La0.7Sr1.3CoO4 to 0.56 Ωcm2 for La0.7Sr1.3Co0.8Fe0.2O4 sample and 0.38 Ωcm2 for La0.7Sr1.3Co0.8Cu0.2O4. The results revealed that Cu doping La0.7Sr1.3CoO4 improves the cathodic performance of La0.7Sr1.3CoO4, significantly. So we can conclude that Cu doped La0.7Sr1.3CoO4 can be a good cathode candidate to be used in intermediate solid oxide fuel cells.