Reaction tuned formation of hierarchical BaCo0.4Fe0.4Zr0.1Y0.1O3-δ cathode

Abstract Here it is demonstrated that the hierarchical BaCo0.4Fe0.4Zr0.1Y0.1O3-δ perovskite (BCFZY) cathode with 40–100 nm BCFZY nanoparticles uniformly decorated on porous BCFZY framework can be directly obtained through a reaction tuned formation process. Triggered by the reaction with H2O, BCFZY surface layers exfoliate to nanocomposite particles on surfaces. Uniformly dispersed nanocomposite particles on surfaces are achieved from the reaction of BCFZY with H2O and CO2 from the air. These nanocomposite particles can be converted to poly-structured BCFZY nanoparticles at temperatures above 800 °C. The reactions to nanocomposite particles and then to BCFZY nanoparticles successively occur during sintering BCFZY cathode into the cell. The single cell with the hierarchical BCFZY cathode outputs 1.61 W cm−2 (2.30 A cm−2) at 0.70 V and 700 °C and exhibits an extremely low polarization resistance from oxygen reduction reaction.