Evaluation of Ba-deficient PrBa1-xFe2O5+delta oxides as cathode materials for intermediate-temperature solid oxide fuel cells

Cobalt-free double perovskite oxides are promising cathode materials in intermediate-temperature solid oxide fuel cells, and often suffer from low activity in oxygen reduction reactions. Here, we report on Ba deficiency as an effective strategy to enhance the electrochemical performance of cobalt-free double perovskite PrBaFe2O5+delta, which is related to the formation and redistribution of oxygen vacancies in double perovskite. The effect of Ba deficiency on crystal structure, surface properties, oxygen content, electrical conductivity, thermal expansion, chemical compatibility with gadolinium-doped ceria (Gd0.1Ce0.9O1.95) electrolyte, microstructure, and electrochemical performance of PrBa1-xFe2O5+delta (x = 0.00-0.03) was evaluated systematically. Our preliminary results suggest that Ba deficiency is a feasible means to tailor the physico-and electrochemical properties of cobalt-free double perovskite, and that PrBa0.97Fe2O5+delta is a potential cathode material for intermediate-temperature solid oxide fuel cells.