Synthesis and Properties of Rare Earth-doped Ceria as Solid Electrolyte of Fuel Cell

稀土掺杂二氧化铈燃料电池固体电解质的合成及性能

• 批准号: 09650926
• 负责人: HIRATA Yoshihiro
• 金额: $ 2.11万
• 依托单位: Kagoshima University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650926/
• 关键词: Ceria; Rare Earth Element; Solid Electrolyte; Fuel Cell; Oxygen Ion Conductor

Doped ceria, which has a higher oxygen ion conductivity in yttria-stabilized zirconia, is one of the possible electrolyte for solid oxide fuel cell at low temperatures. This research covers powder preparation, densification and electrical, mechanical and thermal properties of rare earth-doped ceria. Rare earth-doped ceria powders with a composition of Ce0.8R0.2O1.9 (R=Yb,Y,Gd,Sm,Nd and La) were prepared by heating the oxalate coprecipitate where a mixed R/Ce nitrates solution was added to an oxalic solution. This method provided the oxalate solid solutions containing Ce and R, which were calcined to form the oxide solid solutions at 600℃ in air. The sizes of oxalates and oxides depended on the concentration of oxalic acid and showed a minimum at 0.4 M oxalic acid. The primary oxide particles of 24-63 nm were formed in the skeleton particle clusters of median size of 2μm. The lattice parameters of oxide powders increased linearly with increasing ionic radius of doped rare earth. These r … More are earth-doped ceria powders were formed by uniaxial pressing (49 Mpa) and following cold isostatic pressing (294 Mpa). The samples were densified above 98% relative density by the sintering at 1600℃ for 4 h. The grain sizes (4.7-7.6μm) of samples sintered at 1600℃ showed a tendency to become larger with increasing ionic radius of doped-rare earth element. Observation of rare earth-doped ceria by high magnification transmission electron microscopy indicated that no crystalline or amorphous phase existed at grain boundaries and the dopants of rare earth elements were uniformly distributed in bulk and at grain boundaries. The electrical conductivity of rare earth-doped ceria ceramics was dominated by the migration of oxygen ions in bulk and was in the rage of 6.7- 14.0 S・mィイD1-1ィエD1 at 800℃. The activation energies for diffusion of oxygen ions was lower for the bulk (75-93 kJ/mol) than for grain boundary (101-123 kJ/mol). The activation energies decreased as the ionic radius of rare earth element dopant increased from 0.099 to 0. 105 nm. The diffusion coefficients of oxygen ions in rare earth-doped ceria except for Ce0.8Y0.2O1.9 and pure CeO2, which were calculated from the measured bulk conductivity, were in good agreement with those measured by the tracar method. No significant influence of doped rare earth element on the thermal expansion coefficient of CeO2 was measured (11.4-12.2 x10ィイD1-6ィエD1KィイD1-1ィエD1). The four-point flexural test offered 158-178 Gpa of Young's modulus, 53-81 MPa of strength and 9.1 of Weibull modulus for Ce0.8Sm0.2O1.9 with 86-98% relative density. Less

掺杂氧化铈在氧化钇稳定的氧化锆中具有更高的氧离子电导率，是低温固体氧化物燃料电池可能的电解质之一。本论文主要研究稀土掺杂氧化铈的粉体制备、致密化以及电性能、力学性能和热性能。采用草酸盐共沉淀法制备了稀土掺杂Ce0.8R0.2O1.9（R=Yb，Y，Gd，Sm，Nd和La）氧化铈粉体。该方法制备了含铈和稀土元素的草酸盐固溶体，在空气中于600℃煅烧形成氧化物固溶体。草酸盐和氧化物的大小取决于草酸的浓度，并显示在0.4 M草酸的最小值。在中位粒径为2μm的骨架颗粒团簇中形成了24-63 nm的一次氧化物颗粒。氧化物粉体的晶格常数随掺杂稀土离子半径的增大而线性增大。这些r ...更多信息 通过单轴压制（49 Mpa）和冷等静压（294 Mpa）形成掺土二氧化铈粉末。在1600℃烧结4 h，试样的致密度可达98%以上。在1600℃烧结的样品中，晶粒尺寸（4.7-7.6μm）随掺杂稀土离子半径的增大而增大。用高倍率透射电镜观察稀土掺杂氧化铈的晶相和非晶相，结果表明，稀土元素的掺杂均匀地分布在体相和晶界上。稀土掺杂氧化铈陶瓷的电导率主要受体相氧离子迁移的影响，800℃时电导率为6.7- 14.0 S·m ~（-1）·cm ~（-1）·D ~（-1）。氧离子扩散激活能在体相（75-93 kJ/mol）低于晶界（101-123 kJ/mol）。随着稀土离子半径从0.099增大到0.099，激活能逐渐减小。105纳米。氧离子在除Ce0.8Y0.2O1.9和纯CeO 2外的稀土掺杂氧化铈中的扩散系数由体电导率计算得到，与用示踪法测得的结果吻合较好。掺杂的稀土元素对CeO 2的热膨胀系数没有显著影响（11.4-12.2 × 10 ~（-1）D1-6 × 10 ~（-1）D1）。四点弯曲试验提供了158-178 Gpa的杨氏模量，53-81 MPa的强度和9.1的Weibull模量的Ce0.8Sm0.2O1.9与86-98%的相对密度。少

项目成果

K. Higashi et al.: "Characterization of rare Earth-doped Ceria Powder Derived from Oxalate Coprecipitate"Key Engineering materials. 159-160. 25-30 (1999)

K. Higashi等人：“草酸共沉淀物衍生的稀土掺杂二氧化铈粉末的表征”关键工程材料。

S. Sameshima et al.: "Sintering and Grain growth of rare Earth-doped ceria particles"Proceedings of The 3rd Nano Ceramic Forum and The 2nd International Symposium on Intermaterials. 163-166 (1999)

S. Sameshima等人：“稀土掺杂二氧化铈颗粒的烧结和晶粒生长”第三届纳米陶瓷论坛和第二届国际材料研讨会论文集。

S. Sameshima et al.: "Thermal and Mechanical Properties of Rare earth-doped Ceria Ceramics"Materials Chemistry and Physics. 61. 31-35 (1999)

S. Sameshima 等人：“稀土掺杂二氧化铈陶瓷的热力学性能”材料化学和物理。

K.Higashi, K.Sonoda, H.Ono, S.Sameshima and Y.Hirata: "Characterization of Rare Earth-Doped Ceria Powder Derived from Oxalate Coprecipitate"Key Engineering Materials. Vol. 159-160, Proceedings of International Symposium on Novel Synthesis and Processing o

K.Higashi、K.Sonoda、H.Ono、S.Sameshima 和 Y.Hirata：“草酸共沉淀物衍生的稀土掺杂二氧化铈粉末的表征”关键工程材料。

K.Higashi: "Synthesis and Sintering of Rare Earth-doped Ceria Powder by Oxalate Coprecipitation Method" Journal of Material Research. Vol.14,No.3(印刷中). (1999)

K. Higashi：“草酸盐共沉淀法合成和烧结稀土掺杂二氧化铈粉末”《材料研究杂志》第 14 卷，第 3 期（出版中）。