ADVANCED CHARACTERISATION TECHNIQUES FOR NICKEL-YSZ CERMET ELECTRODES USED IN SOLID OXIDE FUEL CELLS

摘要

The functioning of a complex system such as the Nickel-Yttria stabilised Zirconia cermet electrode for solid oxide fuel cells can only be investigated by using a broad range of tools. Theoretical calculations on ageing of Ni/YSZ-cermet anodes show a large influence of the ceramic structure on the rate of sintering. Depending on the conditions this sintering may be catastrophic for the activity of the electrode or even increase the electrode activity. Accurately determined microstructural parameters for a cermet anode allow the use of a newly developed theory linking the reaction resistance of an anode to the porosity and mean pore radius. Electrochemical measurements of a model system of Au on YSZ single crystals show a complex behaviour. Analysis of this system results in a better understanding of the charge distribution at the electrode-electrolyte interface. Kinetic studies on a screen printed Ni/YSZ-cermet anode result in a reaction model for the anodic reaction. Information obtained from impedance spectroscopy is corroborating a proposed reaction model based on data from current-voltage experiments. Infrared spectroscopy at elevated temperatures on a model cermet anode gives first results of the interaction between the anode material and carbon monoxide.