Electrochemical characterization of mixed conducting and composite SOFC cathodes

The electrochemical performance of La0.58Sr0.4Co0.2Fe0.8O3−δ (L58SCF), La0.9Sr1.1FeO4−δ (LS2F) and LSM (La0.65Sr0.3MnO3−δ)/LSM-YSZ (50 wt.% LSM-50 wt.% ZrO2 (8 mol% Y2O3)) cathode electrodes interfaced to a double layer Ce0.8Gd0.2O2−δ (CGO)/YSZ electrolyte was studied in the temperature range of 600 to 850 °C and under flow of 21% O2/He mixture, using impedance spectroscopy and current density-overpotential measurements. The L58SCF cathode exhibited the highest electrocatalytic activity for oxygen reduction, according to the order: LS2F/CGO/YSZ ≤ LSM/LSM-YSZ/CGO/YSZ < L58SCF/CGO/YSZ.