Development of electrolyte-supported intermediate-temperature single-chamber solid oxide fuel cells using Ln(0.7)Sr(0.3)Fe(0.8)Co(0.2)O(3-d) (Ln = Pr, La, Gd) cathodes

Iron-cobalt-based perovskite oxides with general formula Ln(0.7)Sr(0.3)Fe(0.8)Co(0.2)O(3- d) (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 GdFeO(3)-type structure and, for all samples, a mean particle size of less than 1 km 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 AgLn(0.7)Sr(0.3)Fe(0.8)Co(0.2)O(3- d)SDCNiO-SDCPt 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.