Single solution spray pyrolysis of La0.6Sr0.4Co0.2Fe0.8O3 − δ–Ce0.8Gd0.2O1.9 (LSCF–CGO) thin film cathodes

Thin film (200–300 nm) (X)La0.6Sr0.4Co0.2Fe0.8O3 − δ–(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 °C. Segregation of the films into distinct LSCF and CGO phases was observed by X-ray diffraction after annealing above 650 °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 °C. The polarization resistance of films fired at 700 °C were modeled using a Gerischer impedance with a characteristic polarization resistance Rc and time constant tc. Relative to pure LSCF films, the LSCF–CGO composites exhibited lower activation energies resulting in a smaller polarization resistance at operating temperatures below 600 °C.