Optimal Ratio of Particle Size in YSZ-Supported Ni-YSZ Anode Material for SOFC

摘要

Ni-YSZ cermets are generally used as anode in SOFC. In the previous study, authors proposed a new conceptual microstructure of the anode, referred to as "YSZ-supported anodes". A feature of this concept is that YSZ powders are divided into two kinds, coarse and fine. An analysis of anodic performance revealed improved long-term stability, and then results of the investigation on volume shrinkage, porosity and electrical conductivity under both SOFC fabrication and operation atmospheres provided evidence to determine an optimal mixture ratio. In this study, a reduction test, electrical conductivity measurements and analysis with the percolation theory were carried out to optimize the particle size ratio of both coarse and fine YSZ powders and NiO by samples prepared with the varying ratios. Although it can be considered that there is no effect of the ratio to volume shrinkage under reduction atmosphere, it was found that the electrical conductivity and porosity had been affected by the particle sizes.