Fabrication of YSZ/SNDC Bilayer Electrolytes by Spark Plasma Sintering

Abstract

Doped ceria has been reported as a promising candidate of electrolyte applicable for solid oxide fuel cells (SOFCs) and oxygen sensors due to its high ionic conductivity at intermediate temperature. However, it suffers from certain limitations including the existence of electronic conductivity at reduced atmosphere, which would thus increase the leakage current in cells, and the low fracture strength. In this work, we fabricated a bilayer electrolyte with samarium and neodymium co-doped ceria (SNDC) and yttrium stabilized zirconia (YSZ) using spark plasma sintering (SPS) method, which possess the advantages of two layers, high conductivity of SNDC and good electron blocking ability of YSZ. Both layers of the specimen we obtained were dense and well crystallized according to the scanning electron microscope (SEM) and X-ray diffraction (XRD). The bilayer electrolyte exhibits improved ionic conductivity than YSZ with the value of 1.7 S/cm at 550.