Synthesis and electrochemical performance of Ce1 − xYbxO2 − x/2 solid electrolytes: The potential of microwave sintering

Reaction-synthesized ytterbium-doped ceria (Ce1 − xYbxO2 − x/2; x = 0.2 and 0.5) ceramics have been prepared by microwave and conventional sintering approaches. X-ray powder diffraction confirmed the attainment of the fluorite-type structure with similar lattice parameter, regardless the sintering route used. Microwave sintering produces high-density Ce1 − xYbxO2 − x/2 ceramics with grain size (˂2 μm) lower than the conventional ones (5-10 μm). Electrochemical impedance spectroscopy carried out in air atmosphere revealed that microwave processed samples have higher bulk conductivity compared to conventional ceramics. The low activation energy of microwave sintered samples indicates that it is a very attractive process for obtaining solid electrolytes for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs).