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

Abstract

Abstract Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3− δ (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 °C for 5 h 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 μm 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 Ω cm 2 at 600 °C, whereas that of the BSCF powder cathode was 0.468 Ω cm 2 under similar conditions.