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

Abstract

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 (r p) and capacitance (C p) from the anode. It was confirmed that the r p became lower and C p 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.