Abstract
The study is focused on the synthesis and characterization of (La0.75Ca0.25)0.95Cr1-xFexO3-δ (x = 0.3 – 0.9)perovskites as potential materials for solid oxide fuel cell (SOFC) cathode and anode. These materials possessanorthorhombically-distorted structure at room temperature whilst heating above 800- 1100 K induces reversible transformation into the rhombohedral symmetry. The transition temperature increases with iron content. The linear thermal expansion coefficients vary in the range (10.5-11.1)×10 -6 K-1 and slightly grow on Fe-doping.The volume changes upon reduction are within 0.16%. The electronic conductivity exhibits a thermally-activated character and increases on Fe introduction, in particular due to an enhancement of the number of sites available for electronic transfer; this trend is observed both under oxidizing and reducing conditions. The low level of the electronic conductivity seems to be responsible for an insufficient electrochemical activity of (La0.75Ca0.25)0.95Cr1-xFexO3-δ-based cathodes.Under anodic conditions, other factors, such as electrode microstructure or surface-related properties, affect the electrochemical behavior.