连续变化电导池常数法测定电导率的等效电路分析及应用

Equivalent circuit analysis and application for electrical conductivity measurement by continuously varying cell constant technique

通过分析所得的交流阻抗谱,探讨了采用交流阻抗技术使用连续变化电导池常数法测定溶液和熔盐电导率的合理实验条件。通过对交流阻抗等效电路进行分析,认为实验电路的交流阻抗过程是电化学极化与浓差极化共同控制的过程,对于溶液来说,扩散体现出Warburg扩散特性,而熔盐的扩散体现出Gerischer特性。采用边连续变化电导池常数公式进行电导率计算时,对应的电路电阻最好选择对所得的Nyquist图拟合分析所得的溶液/熔盐与电极及导线电阻之和。如果考虑拟合误差,也可以采用读取高频率时电路电阻的方法来进行计算。

The alternating current （AC） impedance spectroscopies of continuously varying cell constant （CVCC） experimental conductivity cell system for solution and melts electrical conductivity measurement were analyzed. The AC impedance rational condition for electrical conductivity measurement by CVCC technique was determined. The AC impedance course of the circuit researched is controlled by both of electrochemical polarization and concentration polarization, Warburg diffusion character is represented for AC impedance diffusion course of solution, meanwhile, the melts concentration polarization impedance is assumed to be Gerischer impedance through equivalent circuit analysis of AC impedance. When the electrical conductivity is calculated by CVCC equation, the best option of the circuit resistance is the sum of solution and melts resistance and electrode and line resistance gained by fitting the equivalent circuit. If fitting error is considered, the circuit high frequency resistance is also a good option.