Synthesis and characterization of La0.6Sr0.4Co0.2Fe0.8O3-delta and Ba0.5Sr0.5Co0.8Fe0.2O3-delta

This study compares the electrical transport and the oxygen exchange properties of two mixed conducting materials between 600 and 800 degrees C, namely La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF) and Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF). Both materials were synthesized by spray pyrolysis and characterized by the electrical conductivity relaxation technique. LSCF has the higher electrical conductivity (257-412 S cm(-1) between 450 and 900 degrees C), while BSCF shows faster oxygen exchange kinetics and diffusion. The expansion of both materials between 600 and 800 degrees C (BSCF = 27.3 ppm/K, LSCF = 15.5 ppm/K below 700 degrees C up to 27.5 ppm/K at T > 800 degrees C) does not match with the common electrolytes for solid oxide fuel cells. (C) 2008 The Electrochemical Society.