Electrode Resistance of Pt/YSZ Oxygen Sensor and Response Behaviour

The Pt, air/YSZ electrode resistance was determined for oxygen sensor with dc polarization oftwo electrode in the temperature range of 380～800℃. The (ZrO2)0.93(Y2O3)0.07 bulk resistanceswere obtained from the extrapolation method by ac low frequency impedance measurement, andthe electrolyte dc polarization resistance can be separated from electrode overpotentiajs. Resultsshow the η - I curves obey the Butler-Volmer equation, with charge transfer coefficients of twofor the Pt, air |YSZ| air, Pt cell. The temperature dependence of the YSZ bulk resistance andthe Pt, air/YSZ electrode resistance is similar and a change in the activation energy of resistanceoccurs near 600℃ and 570℃ respectively. The exchange current to of electrode as a function oftemperature was also measured. At temperature above 700℃, response time of the oxygen sensoris less than 2.5s.