Experimental and Theoretical Investigation of Degradation Mechanisms by Particle Coarsening in SOFC Electrodes

Performance degradation data obtained from single Solid oxide fuel cells, tested at 850 degrees C with air and humidified H(2) and using Ni-YSZ anode supported cells, are presented here. Microscopic investigation is carried out on both anode and cathode to quantify variations in the morphology at different operation times. The comparison between the measurements On the cells and the SEM Image analysis, allows to conclude that there is no relationship between the initial cell activation and microstructural modifications of the electrodes. On the other hand, it was found that cell degradation is Strictly related to the coarsening of Ni particles occurring in the anode. A theoretical analysis based. on an electrode micro-model has been performed in order to compare the variation in performance, expected from particle size change, with the observed data. The model confirmed the conclusions of the experimental results.