Effect of Synthetic Approaches and Sintering Additives upon Physicochemical and Electrophysical Properties of Solid Solutions in the System (CeO 2) 1−x (Nd 2 O 3) x for Fuel Cell Electrolytes.

Finely dispersed (CeO₂)_1−x(Nd₂O₃)_x (x = 0.05, 0.10, 0.15, 0.20, 0.25) powders are synthesized via liquid-phase techniques based on the co-precipitation of hydroxides and co-crystallization of nitrates. The prepared powders are used to obtain ceramic materials comprising fluorite-like solid solutions with the coherent scattering region (CSR) of about 88 nm (upon annealing at 1300 °C) and open porosity in the range of 1–15%. The effect of the synthesis procedure and sintering additives (SiO₂, ZnO) on physicochemical and electrophysical properties of the resulting ceramics is studied. The prepared materials are found to possess a predominantly ionic type of electric conductivity with ion transfer numbers t_i = 0.96–0.71 in the temperature range of 300–700 °C. The conductivity in solid solutions follows a vacancy mechanism with σ_{700 °C} = 0.48 × 10⁻² S/cm. Physicochemical properties (density, open porosity, type and mechanism of electrical conductivity) of the obtained ceramic materials make them promising as solid oxide electrolytes for medium temperature fuel cells. [ABSTRACT FROM AUTHOR]