Towards high performance durable ceramic fuel cells using a triple conducting perovskite cathode

To guarantee the efficient and durable operation of oxygen ion/proton-conducting ceramic fuel cells, the cathode materials need to be versatile in terms of high activity, good CO2 resistance, and matched thermal expansion behavior with electrolyte, etc. In this study, we substituted 10% Nb to the B-site of parent perovskite-BaCo0.7Fe0.2Y0.1O3-δ, to form a single-phase material with triple conducting (H+/O2-/e-) capability as a highly ORR-active cathode. The doped BaCo0.6Fe0.2Y0.1Nb0.1O3-δ (BCFYN) shows promising ORR activity due to the optimized oxygen vacancy, improved hydration capacity, and accelerated charge transfer kinetics. The reduction of thermal expansion coefficient (TEC) and enhanced CO2 resistance also facilitate the cathode durability. As a result, the area-specific resistances of BCFYN electrode at 550°C for oxygen-ion and proton conducting symmetrical cells were only 0.106 and 0.24 Ω cm2, respectively. These results indicate that BCFYN is a highly promising cathode material for both SOFCs and PCFCs.