Investigation of Self-Assembled Dual-Phase Cathodes with Triple Conductivity for Protonic Ceramic Fuel Cells

Efficientcathodes with high catalytic activity and stabilityarecrucial for the development of protonic ceramic fuel cells (PCFCs).Single-phase cathode is difficult to meet multiple requirements, suchas high electrochemical performance, oxygen reducing activity, stability,and CO2-resistance. In this regard, we report self-assembleddual-phase perovskite cathodes Ba-(Co0.7Fe0.3)( x )(Ce0.8Y0.2)(1-x )O3-delta (BCFCY, x = 0.6, 0.7, 0.8) prepared by a one-pot method for PCFCs.The cathode displays a triple O2-/e(-)/H+ conducting behavior, which consists of a cubic phase(C-BCFCY, Co-rich) and a rhombohedral phase (R-BCFCY, Ce-rich) in this perovskite. The C-BCFCY has high O2-/e(-) conductivity and low basicity, while the latter R-BCFCY exhibited excellent hydration performance, which synergisticallyresults in cathode with high electrochemical activity and CO2-resistance. Owing to its appropriate dual phase composition, theBa-(Co0.7Fe0.3)(0.7)(Ce0.8Y0.2)(0.3)O3-delta (BCFCY73)electrode demonstrates low polarization resistance (0.065 omega cm(2)) at 700 degrees C in 5 vol % water steam. The peak powerdensity of anode-supported single cells BZCYYb | BCFCY73 | BZCYYbis 545.3 mW cm(-2) at 700 degrees C. This result provesthat regulating the content of two phases (proton conductors and ionicconductors, respectively) of perovskite oxide by the one-pot methodis an effective strategy to design PCFC cathode materials with highactivity, and this method can also be applied in other energy transfermaterials fields.