Synthesis, characterization and properties of nanocrystalline perovskite cathode materials

A simple low temperature synthesis route has been presented of preparing nanosized, single phased LaFeO(3), La((1-x))Sr(x)FeO(3) (x = 0.3, 0.5) and La((1-x))Sr(x)Co(0.2)Fe(0.8)O(3) (x = 0.2, 0.4) for cathode applications in ITSOFC. A soft chemical method has been applied, using tartaric acid as a template material and nitric acid as an oxidizing agent. Phase pure materials were obtained at temperatures ranging from 550 degrees C to 700 degrees C. The synthesized powders were characterized by TGA, XRD, SEM and FTIR analysis. The crystallite size was 45-50 nm, with the surface area of 14-20 m(2)/g. Electronic conductivity of the material was found to increase upon increasing Sr concentration and the sintering temperature. High electronic conductivities of 355 S/cm and 545 S/cm were obtained at 400 degrees C for La(0.5)Sr(0.5)Fe(2)O(3) and La(0.6)Sr(0.4)Co(0.2)Fe(2)O(3), respectively. Activation energy decreases with the increase in Sr concentration. The values of thermal expansion coefficients (TEC) of the materials are compatible with the TEC of the ceria-gadolinium oxide CGO inter-layer between cathode layer and electrolyte