K-doped BaCo0.4Fe0.4Zr0.2O3−δ as a promising cathode material for protonic ceramic fuel cells

Abstract Slow oxygen reduction reaction (ORR) involving proton transport remains the limiting factor for electrochemical performance of proton-conducting cathodes. To further reduce operating temperature protonic ceramic fuel cells (PCFCs), developing triple-conducting cathodes with excellent is required. In this study, K-doped BaCo 0.4 Fe Zr 0.2 O 3− δ (BCFZ442) series were developed and used as PCFCs, their crystal structure, conductivity, hydration capability, characterized in detail. Among them, Ba 0.9 K 0.1 Co (K10) cathode has best performance, which can be attributed to its high electron (e − )/oxygen ion (O 2− )/H + conductivity uptake capacity. At 750 °C, polarization resistance K10 only 0.009 Ω·cm 2 , peak power density (PPD) single cell close 1 Wcm −2 there no significant degradation within 150 h. Excellent durability make a promising material PCFCs. This work provide guidance improving capability oxides, great significance PCFC performance.