Calcination Temperature Influence on Ionic Conductivity of Solid Electrolytes

The gadolinia doped ceria was developed in Ce0,8Gd0,2O1,9 composition, with the objective to study the influence of calcination temperature on the ionic conductivity of sintered samples (pellets) used as solid electrolyte for the fuel cells applications. The powder was synthesized by the polymeric precursor method (Pechini) from cerium and gadolinium nitrates hexahydrates, obtaining a polymeric resin characterized by infrared spectroscopy. The heat treatments at 600 and 800 degrees C resulted on oxides formation which have been characterized by infrared spectroscopy and X-ray diffraction for each sample. In each case, the fluorite type structure was identified. The pellets were formed by uniaxial pressure and sintered at 1500 degrees C with relative densities of 93.1 and 89.4% for the samples calcined at 600 and 800 degrees C, respectively. The microstructure evaluation was performed by scanning electron microscopy, and the electrical characterization was carried out by impedance spectroscopy, reaching a conductivity of 1.49x10(-4) S/cm at 400 degrees C in this work.