An optimized synthesis route for high performance composite cathode based on a layered perovskite oxide of PrBa0.92Co2O6-δ with cationic deficiency

For Solid Oxide Fuel Cells (SOFCs) to become an economically attractive energy conversion technology, cathode materials with high catalytic activity over oxygen reduction reaction (ORR) and low cost are desired. In this work, a composite cathode material of PrBa0.92Co2O6-δ-40 wt%Ce0.8Sm0.2O1.9(OPCC) based on a layered perovskite oxide of PrBa0.92Co2O6-δ with Ba2+-deficiency at A-sites has been successfully synthesized with a facile and effective one-pot sol-gel method, which was comparatively studied with the counterpart BMCC synthesized with the traditional ball-milling method and the single phase cathode of PrBa0.92Co2O6-δ. Among the three cathodes, OPCC showed the lowest area specific resistances (ASRs) in both air and oxygen atmospheres, indicating the highest ORR catalytic activity. Such performance improvement for OPCC was closely related to its optimized microstructures obtained with the liquid-mixing one-pot synthesis method and existence of Ce0.8Sm0.2O1.9 that has a high ionic conductivity. I-V and I-P curves were measured for the anode-supported single cells with the three cathodes, and the OPCC-based cell showed the highest peak power densities with typical value of 1011  mW cm−2 at 750 °C in contrast to 783  mW cm−2 for the BMCC-based cell and 574  mW cm−2 for the PrBa0.92Co2O6-δ-based cell respectively. The OPCC-based cell also showed a stable performance with no obvious degradation over 100 h at 700 °C.