Functional properties and electrochemical performance of dual-phase Pr0.9Y0.1BaCo2O6-delta-Ce0.8Sm0.2O1.9 composite cathodes

The dual-phase composites are obtained by mixing perovskite-like cobaltite Pr0.9Y0.1BaCo2O6-delta and samarium-doped ceria Ce0.8Sm0.2O1.9 in weight proportions 90/10, 70/30, and 50/50. The absence of chemical interactions between the components at heating up to 1100 A degrees D is confirmed by X-ray powder diffraction measurements. The partial dilution of the cobaltite is accompanied with decreasing thermal expansion of the composite. The impedance measurements reveal linear changes of the area-specific resistance with inverse temperature that correspond to the activation energy values of about 0.9 and 0.8 eV for 70/30 and 50/50 composites, respectively. The overvoltage for oxygen electro-reduction with current density 1 A/cm(2) does not exceed 80 mV at 700 A degrees D. The high electrical conductivity, moderate thermal expansion, and appreciable electrochemical activity single out the mixture of Pr0.9Y0.1BaCo2O6-delta (70 wt%) and Ce0.8Sm0.2O1.9 (30 wt%) as a promising composite cathode material for intermediate temperature solid oxide fuel cell applications (IT-SOFC).