THERMAL EXPANSION BEHAVIOR OF THE Ba0.2Sr0.8Co0.8Fe0.2O3-δ (BSCF) WITH Sm0.2Ce0.8O1.9

Nanostructured perovskite oxides of Ba0.2Sr0.8Co0.8Fe0.2O3-delta (BSCF) were synthesized through the co-precipitation method. The thermal decomposition, phase formation and thermal expansion behavior of BSCF were characterized by thermogravimetric analysis, X-ray diffraction (XRD), and dilatometry, respectively. XRD peaks were indexed to a cubic perovskite structure with a Pm3m (221) space group. All the combined oxides produced the desired perovskite-phase BSCF. The microstructures were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The TEM analysis showed that BSCF powders had uniform nanoparticle sizes and high homogeneity. The cross-sectional SEM micrograph of BSCF exhibited a continuous and no delaminated layer from the electrolyte-supported cell. The thermal expansion coefficient (TEC) of BSCF was 16.2 x 10(-6) K-1 at a temperature range of 600 degrees C to 800 degrees C. Additional experiments showed that the TEC of BSCF is comparable to that of Sm0.2Ce0.8O1.9 (SDC) within the same temperature range. The results demonstrate that BSFC is a promising cathode material for intermediate-temperature solid-oxide fuel cells.