Thin film (200-300 nm) (X)La0.6Sr0.4Co0.2Fe0.8O3-delta-(1 - X)Ce0.8Gd0.2O1.9 (LSCF-CGO, X = 0 to 100 vol.%) composite cathodes were produced by spraying a single precursor solution of nitrate salts onto dense yttria stabilized zirconia electrolyte substrates at temperatures of 235 and 275 degrees C. Segregation of the films into distinct LSCF and CGO phases was observed by X-ray diffraction after annealing above 650 degrees C for 4 h. Grain growth was suppressed in the LSCF-CGO composites relative to pure LSCF, the grain size in 59LSCF-41CGO ranging from 15 to 50 nm for annealing temperatures between 700 and 900 degrees C. The polarization resistance of films fired at 700 degrees C were modeled using a Gerischer impedance with a characteristic polarization resistance R-c and time constant t(c). Relative to pure LSCF films, the LSCF-CGO composites exhibited lower activation energies resulting in a smaller polarization resistance at operating temperatures below 600 degrees C. (C) 2012 Elsevier B.V. All rights reserved.