Synthesis and characterization of nanofiber-structured Ba0.5Sr0.5Co0.8Fe0.2O3-δ perovskite oxide used as a cathode material for low-temperature solid oxide fuel cells

Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) was synthesized in two forms: as a powder (by the sol-gel combined citrate-EDTA complexing (CC-EDTA) method) and as nanofibers (by electrospinning). Both forms were sintered at 950 degrees C for 5h in air before their morphology and structure were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and specific surface area analysis based on the BET theory. Moreover, the mass loss and heat flow of as-electrospun BSCF nanofibers were analyzed by differential thermal analysis (DTA) and thermogravimetric analysis (TG). The results showed that these materials had a perovskite oxide crystal structure. The CC-EDTA method yielded BSCF in powder form, with a particle size of 1-10 mu m and a specific surface area of 1.0 m(2)/g. On the other hand, BSCF obtained by the electrospinning technique was in the form of highly porous nanofibers with diameters in the range of 100-200 nm and a specific surface area of 2.4 m(2)/g. To demonstrate the potential applications of BSCF as a cathode material in low-temperature solid oxide fuel cells (LT-SOFCs), the electrochemical properties of the samples were determined using electrochemical impedance spectroscopy (EIS). The area specific resistance (ASR) of the BSCF nanofiber cathode was determined to be 0.094 Omega cm(2) at 600 degrees C, whereas that of the BSCF powder cathode was 0.468 Omega cm(2) under similar conditions. (C) 2011 Elsevier B.V. All rights reserved.