Development of electrolyte-supported intermediate-temperature single-chamber solid oxide fuel cells using Ln0.7Sr0.3Fe0.8Co0.2O3−δ (Ln = Pr, La, Gd) cathodes

Iron–cobalt-based perovskite oxides with general formula Ln0.7Sr0.3Fe0.8Co0.2O3−δ (where Ln = La, Pr and Gd) have been investigated for their application as intermediate-temperature cathodes in solid oxide fuel cells (SOFCs). Powdered samples of these materials were synthesized by a novel gel combustion process and then characterized by X-ray powder diffraction (XPD) and scanning electron microscopy (SEM). XPD patterns were satisfactorily indexed with an orthorhombic GdFeO3-type structure and, for all samples, a mean particle size of less than 1 μm was estimated from the SEM data. Experimental single-chamber SOFCs using with these materials as cathodes and NiO–SDC (samaria-doped ceria) and SDC as anode and electrolyte, respectively, were evaluated at 600 °C in a methane/oxygen mixtures. Peak power densities of 65.4, 48.7 and 46.2 mW cm−2 were obtained for Ag|Ln0.7Sr0.3Fe0.8Co0.2O3−δ|SDC|NiO–SDC|Pt cells with Ln = Pr, La and Gd, respectively. The relatively high power density obtained for the Pr compound shows that it could be an interesting material for cathode of single-chamber SOFCs.