Effect of Fe Doping on Layered GdBa 0.5 Sr 0.5 Co 2 O 5+δ Perovskite Cathodes for Intermediate Temperature Solid Oxide Fuel Cells

Layered perovskite cathode materials have received considerable attention for intermediate temperature solid oxide fuel cells ( IT ‐ SOFC s) because of their fast oxygen ion diffusion through pore channels and high catalytic activity toward the oxygen reduction reaction ( ORR ) at low temperatures. In this study, we have investigated the effects of Fe substitution for the Co site on electrical and electrochemical properties of a layered perovskite, GdBa 0.5 Sr 0.5 Co 2− x Fe x O 5+δ ( x  =   0, 0.5, and 1.0), as a cathode material for IT ‐ SOFC s. Furthermore, electrochemical properties of GdBa 0.5 Sr 0.5 CoFeO 5+δ – y GDC ( y  =   0, 20, 40, and 50 wt%) cathodes were evaluated to determine the optimized cell performance. At a given temperature, the electrical conductivity and the area‐specific resistances ( ASR s) of GdBa 0.5 Sr 0.5 Co 2− xFe x O 5+δ decrease with Fe content. The lowest ASR of 0.067 Ω·cm 2 was obtained at 873 K for the GdBa 0.5 Sr 0.5 CoFeO 5+δ . The GdBa 0.5 Sr 0.5 CoFeO 5 + δ composite with 40 wt% GDC was identified as an optimum cathode material, showing the highest maximum power density (1.31 W/cm 2 ) at 873 K, and other samples also showed high power density over 1.00 W/cm 2 .