Electrochemical performance and superior CO2 endurance of PrBaCo2O6–δ – PrBaCoTaO6 composite cathode for IT-SOFCs

PrBaCo₂O_6–δ – PrBaCoTaO₆ (PBC/PBCT) composites were studied with respect to their chemical and thermomechanical compatibility with ceria electrolyte (SDC), electrical conductivity, electrochemical performance and reversibility at variations of CO₂ content in the oxidizing atmosphere. The electrochemical impedance spectra of the composite electrodes were analyzed by the distribution of relaxation times technique. The best properties combination was observed for the 75/25 composite containing 25 wt% of PBCT where polarization resistance did not exceed 0.025 Ohm⋅cm² in the air at 1073 K. Though subjected to some degradation in CO₂ rich atmospheres, the 75/25 composite was shown to completely restore its electrochemical activity after annealing in the air at 973 K.