| La1-xCaxFeO3-δ系阴极材料的GNP法合成及电性能研究 |
| Synthesis and Characterization of La1-xCaxFeO3-δ for Cathodes by GNP Method |
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| 摘要: 采用甘氨酸-硝酸盐(GNP)法合成了LaFeO3及La1-xCaxFeO3-δ(x=0.1～0.5)系列粉体，用TG-DTA、XRD、TEM、SEM等对产物形成过程及微结构进行了表征。结果表明，所合成的系列样品均形成钙钛矿结构的单相固溶体。在x≤20mol%的Ca含量范围内，产物为正交钙钛矿结构；当x>30mol%时，转变为立方钙钛矿相。相同条件下产物的衍射峰强度、晶胞体积及晶粒尺寸都随Ca含量的增大而减小。采用直流四端子法测量了烧结体在中温(450～800 ℃)区的电导率。掺杂使样品导电能力显著增强，电导率随Ca2+掺入量的增大先增大后减小，La0.6Ca0.4FeO3-δ样品的电导率最高。在低温段，各样品的导电行为符合小极化子导电机制，导电活化能为13.67～22.70 kJ·mol-1。 |
| 关键词: La1-xCaxFeO3-δ 钙钛矿 中温固体氧化物燃料电池 阴极材料 电导率 |
| 基金项目: |
| Abstract: LaFeO3 and La1-xCaxFeO3-δ with 0.1 ≤ x ≤ 0.5 were synthesized using glycine-nitrate process(GNP). The formation process of perovskite phase and microstructure of the samples were characterized using TG-DTA, XRD, and SEM. The results revealed that fine powders with particle size of 50～90 nm were obtained. All the samples with different doping amounts of Ca2+ on A-site were single phase solid solutions, and the stable perovskite phase was formed completely after calcination at 850 ℃. The solid solutions with 0.0 ≤ x ≤ 0.2 were isostructural with the orthorhombic perovskite-type LaFeO3, while those with composition of 0.3 ≤ x ≤ 0.5 were the cubic perovskite-type system. The diffraction intensity, the cell volume as well as grain size of products decreased with Ca content. The electrical conductivity of sintered samples as a function of both temperature and Ca content were measured by four-probe technique. The Ca doped on A-site of LaFeO3 had a significant effect on electrical properties. The electrical conductivity increased as Ca content and then decreased, La0.6Ca0.4FeO3-δ was found to be of the highest conductivity. The activation energy of La1-xCaxFeO3-δ (0.1 ≤ x ≤ 0.5) was 13.67～22.70 kJ·mol2+, while that of LaFeO3 was 100.89 kJ·mol2+. |
| Keywords: La1-xCaxFeO3-δ perovskite IT-SOFC cathode materials electrical conductivity |
| 投稿时间：2004-11-08 修订日期：2005-01-28 |
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| 陈永红,魏亦军,刘杏芹,孟广耀.La1-xCaxFeO3-δ系阴极材料的GNP法合成及电性能研究[J].无机化学学报,2005,21(5):673-678. |
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