Optimizing thermal expansion and polarization resistance of Ce1−xPrxO2−δ (x = 0.1 and 0.2)/La0.4Pr0.1Ba0.5Co0.975O3−δ composite cathode for IT-SOFC

Abstract

The effect of the weight ratio of composite electrodes Ce1−xPrxO2−δ/La0.4Pr0.1Ba0.5Co0.975O3−δ (x = 0.1 and 0.2) on the thermal expansion and polarization resistance for the oxygen reduction reaction was investigated by dilatometry and electrochemical impedance spectroscopy. The electrode with a 70 wt% of Ce0.9Pr0.1O2−δ shows the best combination of low thermal expansion (16.6 × 10−6 K−1) and low polarization resistance (0.03 Ω cm2 at 700 °C). Incorporating Ce0.9Pr0.1O2−δ the thermal expansion coefficient decreases while maintaining low polarization resistance values comparable to those observed in solely cobaltite-based electrodes, which decreases the cobalt usage in the electrode.