Evaluation of parasitic elements contributing to experimental cell impedance: impedance measurements at interfaces between two immiscible electrolyte solutions
Evaluation of parasitic elements contributing to experimental cell impedance: impedance measurements at interfaces between two immiscible electrolyte solutions
复制标题
评估影响实验电池阻抗的寄生元件：两种不混溶电解质溶液之间界面的阻抗测量
DOI：
--
复制
发表时间：
1996
期刊：
影响因子：
--
通讯作者：
A. Trojanek
中科院分区：
文献类型：
--
作者：
Z. Samec;J. Langmaier;A. Trojanek
这项工作分析了在两个不相容的电解质溶液或膜的界面上测量时所用的四电极电池的阻抗的寄生元件。该单元由等效电路建模，该等效电路考虑了参考电极和对电极的有限阻抗以及各种寄生耦合。该模型允许预测阻抗图显示高频电容性和/或电感性伪影的条件。推导出了由实验阻抗数据计算寄生元件的解析表达式。作为一种极限情况，该模型还描述了三电极电池的行为。通过模拟水/邻硝基苯基辛基醚在1-106 Hz频率范围内的界面阻抗，验证了该方法的有效性。实验数据以高达约20 kHz的频率以极高的精度重现，高于这一频率仅看到定性的一致。尽管观察到了非常高的频率色散，但对寄生贡献的低频实验阻抗的修正对其界面电容、电荷转移电阻或Warburg阻抗的分辨率几乎没有影响。
This work analyses the parasitic elements contributing to the impedance of a four-electrode cell employed in measurements at interfaces of two immiscible electrolyte solutions or membranes. The cell is modelled by an equivalent circuit, which accounts for the finite impedances of the reference and counter electrodes, as well as for various parasitic couplings. The model allows prediction of the conditions under which the impedance plots exhibit the high-frequency capacitive and/or inductive artifacts. An analytical expression is derived, which enables the evaluation of the parasitic elements from experimental impedance data. As a limiting case, the model describes also the behaviour of a three-electrode cell. Its validity is tested by simulating the impedance of a water/o-nitrophenyl octyl ether interface in the range of frequencies 1–106 Hz. Experimental data are reproduced with an excellent precision up to a frequency of ca. 20 kHz, above which only a qualitative agreement is seen. In spite of the remarkably high frequency dispersion observed, the correction of the low-frequency experimental impedance for the parasitic contributions has little effect on its resolution in terms of the interfacial capacitance, charge-transfer resistance or the Warburg impedance.