Abstract
The microstructure and elemental distribution of gadolinium-doped ceria (GDC) thin film electrolyte, Ni-GDC cermet anode and the interface between them were characterized by high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDX) operated in scanning TEM (STEM) mode. HR-TEM and SAED results demonstrate inhomogeneous microstructures formation, i.e. nano-domain and superstructures, at interfacial region. STEM-EDX mapping and line scan analyses illustrate that not only can Ni diffuse into GDC grains as previously reported, but also Ce and Gd cations can diffuse into metallic Ni particles with equal diffusion length as that of Ni diffusion. Therefore, the mutual diffusion and related microstructural evolutions are elucidated to be the dominating factors that lead to the interfacial layer formation between anode and electrolyte, which is identified to have considerable influence on the ionic conductivity behavior in intermediate temperature solid oxide fuel cells.
