Ceramics-Silikáty 58 (1) 46-49 (2014)

THERMAL EXPANSION BEHAVIOR OF THE Ba_0.2Sr_0.8Co_0.8Fe_0.2O_3−δ (BSCF) WITH Sm_0.2Ce_0.8O_1.9

Nanostructured perovskite oxides of Ba_0.2Sr_0.8Co_0.8Fe_0.2O_3−δ (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 16.2×10^-6 K^-1 at a temperature range of 600°C to 800°C. Additional experiments showed that the TEC of BSCF is comparable to that of Sm_0.2Ce_0.8O_1.9 (SDC) within the same temperature range. The results demonstrate that BSFC is a promising cathode material for intermediate-temperature solid-oxide fuel cells.

Keywords: Nanomaterial perovskites, Cathode materials, Solid oxide fuel cell, BSCF, Thermal expansion coefficient