This study reports the successful preparation of potential candidate Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) oxides for intermediate-temperature solid oxide fuel cells (IT-SOFCs) by a combined citrate-ethylenediaminetetraacetic acid (EDTA) complexing method. The resulting crystal properties, chemical composition, conductivity, and electrochemical properties were studied by X-ray diffraction (XRD), inductively coupled plasma mass spectroscopy (ICP-MS), energy dispersive spectrum (EDS), four-point DC measurement and AC impedance. The X-ray diffraction results of all samples with different pH values reveal a basic perovskite structure. Although samples prepared from different pH solutions have a similar structure, their chemical composition and grain morphologies are different. The optimized composition of BSCF is the sample prepared from the precursor solution with a pH value of 6; this produced highest conductivity at 50.2 S/cm at 400 °C, which is 1.3 times higher than the sample prepared from the precursor solution with a pH value of 9. Electrochemical impedance spectra at an intermediate temperature reveal the better electrochemical performance of BSCF electrode prepared from the solution with pH of 6. The lowest polarization resistance values for charge transfer and oxygen diffusion are 0.07 and 0.11 Ω cm2 at 800 °C, respectively.
Inductively Couple Plasma Mass Spectroscopy Precursor Solution Electrochemical Impedance Spectrum Cathode Electrode Energy Dispersive Spectrum
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This study was supported by the National Science Council of Taiwan (NSC 96-2221-E-155-053 and NSC 97-2221-E-155-059).