A study of Pr0.7Sr0.3Fe1−xNixO3−δ as a cathode material for SOFCs with intermediate operating temperature

Pr0.7Sr0.3Fe1−xNixO3−δ (PSFN; x=0.2-0.5) compounds were synthesized and characterized by powder X-ray diffraction (XRD), thermal expansion coefficient (TEC) measurements, electrical conductivity and electrochemical impedance spectroscopy on cone-shaped electrodes on a Ce0.9Gd0.1O1.95 (CGO10) electrolyte. The main phase of the powders belongs to the orthorhombic crystal system. The conductivities are fairly high, e.g., around 450 Scm−1 at 600 °C for the x=0.3 compound. The TEC of the compounds is close to the values of ceria-based electrolytes. PSFN showed hysteresis in the temperature dependence of the conductivity, TEC and area-specific polarization resistance Rpol. It is considered that the hysteresis was caused by relatively slow adjustment of the oxygen stoichiometry. The electrochemical performance Rpol−1 of the PSFN compounds is similar to that of La0.6Sr0.4Fe0.8Co0.2O3−δ.