Sm0.9Ca0.1Al1-xGaxO3-δ钙钛矿氧化物的合成和电学化性能

来源期刊:中国有色金属学报2008年第6期

论文作者:向军 卫婷 刘道明 张淼 王冠洋 伍兴权

文章页码:1117 - 1117

关键词:Sm0.9Ca0.1Al1-xGaxO3-δ;氧离子-电子;混合导体;电化学性能;活化能;

Key words:Sm0.9Ca0.1Al1-xGaxO3-δ; mixed oxide ionic; electronic conductor; electrochemical performance; activation energy

摘    要:

采用固相反应法制备含少量杂质的四方钙钛矿氧化物陶瓷Sm0.9Ca0.1Al1-xGaxO3(x=0.1~0.5)。通过X射线衍射、扫描电镜和交流复阻抗谱以及氧浓差电池等技术研究样品的物相结构、微观形貌、电化学性能和电输运行为。结果表明:Ca、Ga双掺杂能显著提高样品的电化学性能,其电导率随Ga掺杂量x的增加先增大后减小,在x = 0.3时达到最大值;在1 550 ℃ 保温6 h 制得的Sm0.9Ca0.1Al0.7Ga0.3O3样品的相对密度为95.5%,900 ℃时的总电导率为1.83 S/m;Sm0.9Ca0.1Al0.7Ga0.3O3的ln(sT)与T-1之间近似呈线性,说明电导率与温度的关系符合Arrhenius定律,总电导活化能为111.09 kJ/mol;在空气气氛中,该样品是一个氧离子和电子空穴的混合导体,以氧离子导电为主;在测量温度范围内,氧离子迁移数在0.8左右,且随温度升高略微增大;氧离子电导活化能和空穴电导活化能分别为101.08和92.92 kJ/mol。

Abstract: The tetragonal perovskite oxide ceramics Sm0.9Ca0.1Al1-xGaxO3-δ(SCAG, x=0.1-0.5) with low content of impurity phase were synthesized by conventional solid-state reaction method. Their microstructure, morphology, electrochemical performance and transport mechanism were studied by X-ray diffractometry, scanning electron microscopy, alternating current impedance technology and oxygen concentration cell method, respectively. The results show that doubly doping of Ca and Ga can notably improve the electrochemical performance of SmAlO3. The total conductivities of doped samples become large initially while then decreases with increasing Ga content, and reach a maximum value at x= 0.3. Sm0.9Ca0.1Al0.7Ga0.3O3-δ sintered at 1 550 ℃ for 6 h has the highest electrical conductivity of 1.83 S/m at 900 ℃ and relative density of 95.5%. The relationship between ln(sT) and T-1 is basically linear for the Sm0.9Ca0.1Al0.7Ga0.3O3-δ sample, which shows that the temperature dependence of conductivity conforms to the Arrhenius equation in 400-900 ℃, and the activation energy is 111.09 kJ/mol. Sm0.9Ca0.1Al0.7Ga0.3O3-δ is a mixed conductor of oxygen ion and electron hole in air. Its oxygen ion transference number is around 0.8 in the measuring temperature range of 600-900 ℃, and slightly increases with increasing temperature. By means of oxygen ion transference numbers measured in air, the relative contribution of oxygen ion conductivity and electron hole conductivity are separated. Activation energy for oxygen ion conduction of 101.08 kJ/mol is appreciably larger than that for electron hole conduction of 92.92 kJ/mol.

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