Materials Diffusion Stability at Interface Between Stabilized ZrO2 Electrolyte and CeOx Interlayer in Model SOFC Cell

Abstract

We observed the solid state reaction at the interface between ZrO2 electrolyte and CeOx interlayer in a model SOFC. At that interface, ZrOx and CeOx diffuse each other and the Zr-CeO solid solution lowers the cell performance. In this report, diffusion coefficient which enables to predict how much the reaction occurs is derived by using the ZrO2 / CeOx diffusion couples, simulating the long time operation. Stabilized ZrO2 powder and Gd-added CeO2 powder were laminated into two layers and pressed. To measure more practical interface, we chose the material powders used for cell production. Then the pressed powder was sintered at tempertures of 1350 to 1600 oC for 24 hours. The sintered blocks were cut into 3mm thick samples and polished. The ZrOx / CeOx interface were observed by scanning electron microscope (SEM) and analyzed about composition and their amount by Energy-dispersive X-ray spectroscopy (EDS).