Electrode reaction at fixed platinum film. Fixation of platinum film on stabilized-zirconia electrolyte and its effect on the electrode performance of the solid-electrolyte fuel cell.

Abstract

Reliable polarization characteristics of noble metal or oxide electrodes in contact with solid oxide electrolyte are quite important. To obtain such characteristics, we fixed sputtered platinum electrodes on yttria stabilized-zirconia (YSZ) electrolyte by covering the electrode with a porous ceramic layer. As a result of the fixation, the Pt film was kept stable and the resistance of the electrodes was very small.Electrode impedance and potential-current curves were measured on the fixed electrodes. The effect of the oxygen partial pressure, PO2, on the electrode resistance, Ri, which was obtained from the impedance plots, was represented as Ri ∝ PO2–1 at high temperature and low oxygen partial pressure, and as Ri ∝ PO21/4 at low temperature and high oxygen partial pressure. Furthermore, effects of the thickness of the Pt film and the ceramic layer on the polarization characteristics were examined. The cathodic current increased as the Pt thickness decreased. The anodic current increased as the ceramic layer thickness decreased.