In this work, we developed the lanthanum strontium cobalt ferrite and it’s composite with yttrium iron cobaltite (mass ratio of 1:1) cathodes as a thin layer on Ce0.8Sm0.2O1.9 electrolyte. Two kinds of electrode pastes were prepared, with and without 6 mm polystyrene beads as an additional pore former. The performance of cathode materials was investigated by electrochemical impedance spectroscopy as a function of electrode morphology, oxygen partial pressure, potential, and temperature. The polarization resistance of the more porous electrodes was lower than those electrodes prepared without additional pore former in the whole potential range at 800°C, slightly lower at 700°C and 600°C. The addition of yttrium iron cobaltite decreased the performance of both types of cathodes. The lower polarization resistance of porous cathodes is due to the facilitated gas diffusion through their structure.
Composite cathodes contain Ba0.5Sr0.5Co0.8Fe0.2O3-σ and La0.6Sr0.4Co0.8Fe0.2O3-σ were tested in different configuration for achieving cathode of area specific resistance lower than Ba0.5Sr0.5Co0.8Fe0.2O3-σ and La0.6Sr0.4Co0.8Fe0.2O3-σ cathodes. Electrodes were screen printed on samaria-doped ceria electrolyte half-discs and tested in the three electrode setup by the electrochemical impedance spectroscopy. Microstructure was observed by scanning electron microscopy. The lowest area specific resistance 0.46 and 2.77 Ω cm-2 at 700 °C and 600 °C respectively revealed composite cathode contain Ba0.5Sr0.5Co0.8Fe0.2O3-σ and La0.6Sr0.4Co0.8Fe0.2O3-σ in 1:1 weight ratio. The area specific resistance of this cathode is characterized by the lowest activation energy among tested cathodes.
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