Structural, Electrical, and Electrochemical Characteristics of LnBa0.5Sr0.5Co1.5Fe0.5O5+δ (Ln=Pr, Sm, Gd) as Cathode Materials in Intermediate-Temperature Solid Oxide Fuel Cells

Layered perovskite oxides have received great attention as prospective cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) because of their high electrical conductivities and fast oxygen kinetics. Herein, we focus on the structural, electrical, and electrochemical properties of layered perovskites LnBa(0.5)Sr(0.5)Co(1.5)Fe(0.5)O(5+) (LnBSCF, Ln=Pr, Sm, and Gd) as a cathode material for IT-SOFCs. Among the evaluated perovskites, PrBa0.5Sr0.5Co1.5Fe0.5O5+delta (PBSCF) showed the highest electrical conductivity, the highest oxygen content, and the highest values of the oxygen bulk diffusion coefficient (D*) and surface exchange coefficient (k) measured by using isotope oxygen exchange. The composite cathode of PBSCF and gadolinium-doped ceria is the most suitable cathode material for IT-SOFCs among the materials investigated because of its excellent electrochemical properties and fast oxygen kinetics.