Investigation of Structural and Electrical Properties of (Bi₂O₃)_1-x-y(CeO₂)_x(Eu₂O₃)_y Electrolytes for Solid Oxide Fuel Cells

Abstract

In the present study, CeO2 and Eu2O3 doped Bi2O3 composite materials for solid oxide fuel cells were investigated. (Bi2O3)1−x−y(CeO2)x(Eu2O3)y ternary systems (x = 0.01, 0.03, 0.05, 0.07, 0.09, 0.11 and y = 0.11, 0.09, 0.07, 0.05, 0.03, 0.01 dopant concentrations) were fabricated at different temperatures (650, 700, 750, and 800 • C) using conventional solid-state synthesis techniques. Characterization of these electrolyte samples were carried out by X-ray powder diffraction, differential thermal analysis/thermal gravimeter, and the four-point probe technique measurements. X-ray powder diffraction measurements showed that nearly all the samples have α + β + γ phase except the samples with tetragonal β-phase sintered at 700, 750 • C and 750, 800 • C with the dopant ratios (x = 0.07, y = 0.05) and (x = 0.09, y = 0.03), respectively. Four-point probe technique measurements showed that the measured ionic conductivity of the stable samples vary in the range 1.05 × 10 −1-4.76 × 10 −1 S/cm. Additionally, the activation energy values of the samples were calculated with the help of the Arrhenius equation adapted to the logσ graphics versus 1000/T varying in the range 0.7799-0.8746 eV. This result shows that there is a good relationship between the activation energy values and conductivity values.

Phase structure-dependent low temperature ionic conductivity of Sm2O3

“…20 It is a common phenomenon that the same elements can form materials with different crystal structures and physical properties. 21,22 For instance, Borik et al studied the effect of the content of Y 2 O 3 in ZrO 2 -Y 2 O 3 -Eu 2 O 3 solid solution on the crystal structure and ionic conductivity. 23 The results indicate when the molar concentration of Y 2 O 3 is 8%, the crystal structure of the material changes to a fluorite structure and the ionic conductivity is the highest at the same time due to the highest content of active oxygen vacancies.…”