Structure and conductivity characterization of new type ionic conductor stabilized bismuth oxide ternary systems

In this study, the new type electrolyte (Yb₂O₃)_x(Dy₂O₃)_y(Bi₂O₃)_1-x-y ternary compounds were synthesized with different stoichiometric ratios by the solid-state reaction method at different annealing treatment and also their microstructural and electrical properties were analysed. X-ray powder diffraction results showed that the high temperature δ-phase of pure monoclinic Bi₂O₃ has been synthesized by doping of Yb₂O₃. Grain size and grain form of pellet formed samples was compared from their surface images taken by the scanning electron microscopy. The grain size has been varying between ～17–37 µm, and degrading with the increasing dopant concentrations. The relationships between the structural parameters (e.g. lattice parameters, crystallite size and the lattice microstrain) and structural properties (e.g. ionic radii of dopant cations and heat treatment procedure) were particularly discussed. Total conductivity values were calculated by Nyquistic complex impedance plot. Impedance measurement revelaed that total conductivity values of the samples increase with the increasing Yb dopant ratio. The activation energies calculated by the Arrhenius approach are measured at around 1?eV. In addition, activation energies and pre-exponential terms decrease with the increasing Yb cation dopant rate for the same ambient temperature.