Effect of a CGO buffer layer on the performance of (La0.6Sr0.4)0.995Co0.2Fe0.8O3-δ cathode in YSZ-Based SOFC

The electrochemical properties of (La0.6Sr0.4)0.995Co0.2Fe0.8O3-δ (LSCF) and LSCF-gadolinium-doped ceria (CGO) composite electrodes towards oxygen reduction were studied by impedance spectroscopy in a symmetric cell configuration using yttriastabilised zirconia (YSZ) as electrolyte and a CGO buffer layer between the electrode and the electrolyte materials. The best polarisation resistance values were obtained for a LSCF-CGO (60/40, wt.%) composite with values ranging between 0.07 and 0.4 Ωcm2 in the temperature range of 650-775 degree centigrade. The effect of the CGO buffer on the polarisation resistance of the LSCF electrode and the series resistance of the symmetrical LSCF/YSZ cell was also investigated. In addition, X-ray diffraction analysis was carried out to study the chemical compatibility between LSCF, YSZ and CGO materials. (Author)