In this study, the effect of Ni substitution in Co sites of La0.7Sr1.3CoO4 Ruddlesden-Popper oxides was investigated, as cathode for using in solid oxide fuel cells. Structural and lattice dynamic analyses revealed that La0.7Sr1.3Co1−xNixO4 (x = 0, 0.1, 0.3 and 0.5) had tetragonal structure and the lattice volume decreased as a results of Co3+ stabilization in low spin state with substituting Ni ions in Co sites. In addition, the x-ray photo electron spectroscopy (XPS) indicated that Co4+/Co3+ ratio decreases in these synthesized powders with enhancement of Ni dopant, while the oxygen vacancy and the oxygen adsorption in the samples increased. The electrochemical performance of La0.7Sr1.3Co1−xNixO4 synthesized powders was studied using electrochemical impedance analysis of the symmetrical cells. The electrochemical processes were determined by employing distribution of relaxation time (DRT) analysis. It was revealed that doping of La0.7Sr1.3CoO4 with Ni leads to decreasing the polarization area specific resistance from 1.2 Ω cm2 for x = 0 to 0.36 Ω cm2 for x = 0.5 at 800 °C. So, it can be concluded that by Ni substitution in Co sites the cathodic performance of La0.7Sr1.3CoO4 improves significantly and these compounds can be considered as suitable cathode candidates to be used in IT-SOFC.

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