Kinetics of NiO reduction and morphological changes in composite anodes of solid oxide fuel cells: Estimate using Raman scattering technique

Resumo

The kinetics of nickel reduction and morphological changes in Ni–10Sc1CeSZ composite anodes in intermediate-temperature solid oxide fuel cells (SOFC) are studied using the Raman spectroscopy technique with the help of application of optically transparent single crystal solid electrolyte membranes and also the thermogravimetric analysis technique. It is shown that the first reduction cycle differs considerably from all the further ones, which is related to morphological changes of nickel grains occurring during the first reduction cycle. A general scheme of occurrence of the process is suggested in studies of model cells using the Raman spectroscopy technique and also in the case of thermogravimetric analysis of powders; it explains the causes for significant differences between the total duration of the process as measured using different techniques. The results of the work can be used for optimization of the mode of initial reduction of the anodic SOFC electrode.