电流驰豫法测试氧化镧掺杂氧化铈中氧离子迁移

Investigation of ion transportiation using the method of current relaxation

摘要:

本文采用甘氨酸-硝酸盐法(GNP)合成了Ce0.65La0.35O1.825 (LDC)粉末,在1400℃下烧结10小时得到陶瓷试样,用XRD和SEM表征了样品的物相和表面形貌。用直流电场测试了试样在不同温度下的电流驰豫现象,并计算了不同温度下试样中迁移氧离子数目和材料直流电导率。结果表明,在固态电解质材料中突然施加强电场,可迁移离子基本都发生了位置偏移,但极少部分可以产生长程迁移。随着温度的升高,样品中发生迁移的氧离子数目增加,但都远小于氧空位总量。迁移氧离子数目与温度之间满足阿累尼乌斯公式,其迁移活化能为0.83 eV。

Abstract:

glycine-nitrate process (GNP) was used to synthesis Ce0.65La0.35O1.825 (LDC) powders. The samples were obtained by sintering for 10 h at 1400 ℃. The phase composition and morphology were characterized by XRD and SEM. We measured the current change with time of specimen at different temperatures and thus calculated the transferred number of ions and the DC conductivity. Almost all the mobile ions will shift around their positions, but only tiny portion can migrate through a few lattice length. The number of transferred ions increased with temperature, but far smaller than the total number of oxygen vacancies. The transferred ion number and temperature follows Arrhenius relationship with the activation energy of 0.83 eV.