Determination of Factors Governing Degradation of Anode-Supported Solid Oxide Fuel Cells as Influenced by Current Density and Humidity

In order to understand the degradation mode of the Ni/YSZ anode in anode-supported cells, durability measurements were performed as a function of current density (OCV, 0.25, 0.5, and 1 A/cm 2 ) and humidity and evaluated using electrochemical impedance spectroscopy. The impedance spectra were analyzed using distribution of relaxation times (DRT) method and the corresponding resistances were determined for varied p (O 2 ), p (H 2 ), and p (H 2 O). From the DRT analysis it was revealed that the anode resistance significantly increased when 0.60 bar p (H 2 O) and 1 A/cm 2 was applied to the cell. Microstructural analysis of the cross-section of Ni/YSZ anode using SEM revealed that there are significant changes in the density and particle size of Ni particles and porosity in the anode when higher humidity and current density were applied.