Dependence of the Electrochemical Performance of Ni/YSZ Anode on Water Vapor Partial Pressure

In order to understand the relationship of the electrochemical performance and microstrutural stability with long-term operation of Ni/YSZ porous anode, anode-supported cells were measured by electrochemical impedance spectroscopy (EIS) under two different conditions: dry and wet 1% H2O condition, at 973 K. The impedance spectra from EIS measurement were analyzed by 1-D approximation transmission line model to observe changes in the reaction resistance (rp) and capacitance (Cp) from the anode. It was confirmed that the rp became lower and Cp became higher when atmosphere changed from dry to wet; such changes were expected to be due to the microstructural changes in the anode, such as variations in the contact length between Ni/YSZ. However, it was confirmed that there was almost no change in the microstructure of Ni/YSZ. Therefore, the properties change in this study may not directly correlated to the microstructure, but other factors may arise in the wet condition.