交流复阻抗技术在CaTi0.85Sc0.15O3-α固体电解质中的应用

The application of AC impedance technology on solid electrolyte CaTi0.85Sc0.15O3-α

介绍了交流复阻抗测试技术在固体电解质测试中的应用原理，并对用传统固相反应法合成的样品CaTi0．85Sc0．15O3-α进行了实际应用测试。根据测得的阻抗谱提出了相应的等效电路，用阻抗分析软件对CaTi0．85Sc0．15O3-α在不同温度下的交流阻抗测试结果进行了对比拟合处理，获得了晶粒电阻、晶界电阻，并定量研究了样品中晶粒电导、晶界电导和总电导随测试温度的变化特性。结果表明：Sc掺杂显著提高了样品的电导性能，CaTi0．85Sc0．15O3-α在800℃的电导率达到0．017S／cm，接近于同温度下8YSZ的电导率；在整个测量温度范围内，电导率与温度的关系满足Arrhenius定律，晶界活化能大于晶粒活化能，样品在730℃以下电导率主要取决于晶界电导，在730℃以上电导率主要由晶粒电导所决定。

The measuring principle of AC impedance applying for the solid electrolyte was introduced. The solid electrolyte CaTi0.85Sc0.15O3-α which was synthesized by solid state reaction method was tested by means of equipment of AC impedance. Equivalent circuit was proposed according to the measured impedance spectra. The AC impedance tested results of CaTi0.85Sc0.15O3-α at different temperature were fitted using impedance analysis software. At the same time, the resistances of grain and grain boundary of sample were obtained. The characteristic variety of conductivities of grain, grain boundary and bulk with measuring temperature were definitely studied. The result showed that doping of Sc increased the electrical conductivity of the sample significantly, the electrical conductivity of CaTi0.85Sc0.15O3-α was 0. 017 S/cm at 800℃, and was comparable to that of 8YSZ. The temperature dependence of conductivity satisfied the Arrhenius empirical formula in measured temperature range. In addition, it has been found that the activation energy of grain boundary was more than that of grain, the conductivity of CaTi0.85 Sc0. 15 O3-α was controlled by grain boundary processes below 730℃, and was controlled by grain processes above 730 ℃.