Abstract
Bi1−x Nb x O1.5+δ (x = 0.15–0.25) and Bi1-y Y y O1.5 (y = 0.2–0.3) electrolytes were synthesized using solid-state reaction. The electrolytes have a δ-Bi2O3 structure and are stable at room temperature. A Bi0.8Y0.2O1.5 sample that was sintered at 950°C showed the highest conductivity of ∼1.97 S/cm at 800°C, while that of Bi0.85Nb0.15O1.5 + δ sintered at 950°C is 0.41 S/cm. The grain sizes of the Bi0.85Nb0.15O1.5+ δ and Bi0.8Y0.2O1.5 samples sintered at 950°C are ∼29.4 and 10.6 μm, respectively. The thermal expansion coefficients of the Bi0.85Nb0.15O1.5+ δ sample are 12.1 × 10−6/°C at 30–500°C and 22.3 × 10−6/°C at 500–800°C, while those of the Bi0.8Y0.2O1.5 sample are 15.4 × 10−6/°C at 30–500°C and 20.3 × 10−6/°C at 500–800°C.
Acknowledgments
We thank the National Science Council of Taiwan for funding support through contracts NSC 100–2221-E-027–109 and NSC 101-2221-E-027-021.