Polarisation conductivity of the O2,Pt/Zr(Y)O2 and H2-H2O, Pt/Zr(Y)O2 electrodes

Pt electrodes with defined contact geometries were studied by using impedance spectroscopy. The specific polarisation conductivity per unit length of the three-phase boundary was determined. It is found to be 1 × 10−4 S·cm−1 at 977 °C in an atmosphere of “pure” hydrogen with an oxygen partial pressure of 10−20 atm at 1000 °C. Investigations carried out in an atmosphere of pure oxygen revealed a pronounced dependence of the polarisation conductivity on the electrode history. The polarisation conductivity was found to be in a range of 2 × 10−4 to 6.5 × 10−4 S·cm−1 at a temperature of 977 °C. It was possible to estimate the area of the electrolyte surface which takes part in the electrode reaction. The real exchange current density was determined.