Dense Y-PSZ electrolyte with high ionic conductivity prepared by spark plasma sintering

In this study, yttria partially stabilized zirconia (Y-PSZ) powders have been prepared using the Pechini sol–gel method with molar ratios of 4, 6 and 8 acids citric to total moles of cations. To determine the density of samples and the measurement of ionic conductivity, the pellet of samples was produced using spark plasma sintering at different sintering temperatures. The density of the pellets was determined by the Archimedes method, which was from 92 to 99.9% compared to their theoretical density. Structural and microstructural properties of the optimal pellet were investigated using X-ray diffraction pattern (XRD), Raman spectroscopy and field-emission scanning electron microscopy (FE-SEM). XRD data and Raman spectrum analysis show that the crystalline structure is mainly cubic with a tetragonal phase. FE-SEM images show that the particle shape of powders is spherical with a likely uniform particle size distribution and the average sizes of particles are about 29 nm. The electrochemical properties of the optimal sample were measured by the electrochemical impedance spectrum. The results of ionic conductivity measurements in the range of room temperature up to 1000°C show the Y-PSZ optimal sample has conductivity higher than the other counterpart samples and is comparable to the 8YSZ conductivity. The association binding energy, the activation energy and the mobility energy of the optimum pellet have been calculated from the slope of the Arrhenius diagram.