SrCe_(0.9)Yb_(0.1)O_(3-α)陶瓷的导电性

Electrical Conductivity of SrCe_(0.9)Yb_(0.1)O_(3-α) Ceramic

以高温固相反应法合成了质子导电性氧化物陶瓷SrCe0 .9Yb0 .1O3 -α.粉末XRD结果表明 ,该陶瓷样品为单一斜方相钙钛矿型结构 .以陶瓷样品为固体电解质、多孔性铂为电极 ,采用交流阻抗谱技术和气体浓差电池方法分别测定了样品在60 0～ 10 0 0℃下、干燥空气及湿润氢气中的电导率及离子迁移数 ,研究了样品的离子导电特性 .结果表明 ,在 60 0～ 10 0 0℃下干燥空气中 ,陶瓷样品的最大电导率为 0 .0 2 6S·cm-1,氧离子迁移数为 0 .0 3～ 0 .2 ,是一个氧离子与空穴的混合导体 ;在湿润氢气中 ,陶瓷样品的最大电导率为 0 .0 15S·cm-1.60 0～ 80 0℃时 ,陶瓷样品的质子迁移数为 1,是一个纯的质子导体 ,而在 90 0～ 10 0 0℃时 ,陶瓷样品的质子迁移数为 0 .91～ 0 .97,是一个质子与电子的混合导体 。

Proton-conducting SrCe 0.9Yb 0.1O 3-α ceramic was prepared by high-temperature solid state reaction. X-ray powder diffraction pattern shows that the ceramic is of a single orthorhombic phase of perovskite-type SrCeO 3. Using the ceramic as solid electrolyte and porous platinum as electrodes, the measurements of conductivities and ionic transport numbers on SrCe 0.9Yb 0.1O 3-α ceramic were performed by using ac impedence spectroscopy and gas concentration cell methods in the temperature range of 600～1000 ℃ in dry air and wet hydrogen, respectively. The results indicate that the sample is a mixed conductor of oxide-ion and hole with the maximal conductivity of 0.026 S·cm -1 and the oxide-ionic transport numbers of 0.03～0.2 in dry air. In wet hydrogen atmosphere, the sample has the maximal conductivity of 0.015 S·cm -1. The protonic transport number is unity and the sample is a pure protonic conductor from 600 to 800 ℃. But in the temperature range of 900～1000 ℃, the sample exhibited a mixed conduction of proton and electron with the protonic transport numbers of 0.91～0.97.