Microstructure and electrode properties of La0.6Sr0.4Co0.2Fe0.8O3-δ spin-coated on Ce0.8Sm0.2O2-δ electrolyte

Fine and uniform La0.6Sr0.4Co0.2Fe0.8O3-delta powder was synthesized by a glycine-nitrate combustion process. La0.6Sr0.4Co0.2Fe0.8O3-delta electrodes were prepared on dense Ce0.8Sm0.2O2-delta electrolyte substrates using a spin-coating technique by sintering at 900-1,000 A degrees C. The electrode properties of La0.6Sr0.4Co0.2Fe0.8O3-delta were investigated by electrochemical impedance spectroscopy and chronopotentiometry techniques with respect to preparation conditions and the resulting microstructures. The results indicate a significant effect of the microstructure on the electrode processes and polarization characteristics. The oxygen adsorption and dissociation process acted as a larger contribution to the overall electrode polarization R (p) in magnitude compared with the charge transfer process due to relatively low porosity levels of the electrodes. It was detected that the grain size of the electrodes exhibited a crucial role on the electrocatalytic reactivity. At 800 A degrees C, the electrode sintered at 950 A degrees C attained a polarization resistance of 0.18 Omega cm(2), an overpotential of 27 mV at a current density of 200 mA cm(-2), and an exchange current density of 308 mA cm(-2).