How does the solution resistance influence the electrochemical behavior of porous electrodes?

IF 4.1 3区化学 Q1 CHEMISTRY, ANALYTICAL

Journal of Electroanalytical Chemistry Pub Date : 2024-10-28 DOI:10.1016/j.jelechem.2024.118746

Andrzej Lasia

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Abstract

In our recent papers simplified models of the porous electrodes in the presence of the electroactive species were presented. In this work, these models are compared with the full model, which considers dc concentration and potential gradients in the pore and the ac effect by division of the pore length into small sections and addition of the solution resistance to the electrode impedance of each section. Simulations for different porosity, concentration, kinetics, and solution resistivity were carried out and allowed to estimate the influence of these factors on the observed complex plane impedance plots. Presence of the dc gradients changes the size of the two semicircles while the ac solution resistance causes formation of the high-frequency straight line at 45° on the complex plane plots. Porosity effects are larger when the total impedance is smaller, that is for higher currents and concentrations of electroactive species and faster kinetics. Estimation of the porosity parameter (Thiele modulus),

Φ_{0}

, and the parameter v, which relates concentration and potential in pores, allows for the estimation of the porosity effects on the impedance.

In the absence of the concentration gradient (i.e.potential gradient only present), a straight line at 45° followed by one skewed semicircle is observed. Conditions for obtaining such impedances are discussed.

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溶液电阻如何影响多孔电极的电化学行为？

我们在最近的论文中介绍了电活性物质存在时多孔电极的简化模型。在这项工作中，我们将这些模型与完整模型进行了比较，完整模型考虑了孔隙中的直流浓度和电位梯度，以及通过将孔隙长度划分为小段并在每段电极阻抗中加入溶液电阻而产生的交流效应。对不同的孔隙率、浓度、动力学和溶液电阻率进行了模拟，从而估算出这些因素对观测到的复平面阻抗图的影响。直流梯度的存在会改变两个半圆的大小，而交流溶液电阻则会在复平面图上形成 45°的高频直线。当总阻抗较小时，即电流和电活性物质浓度较高且动力学速度较快时，孔隙度效应较大。通过估算孔隙度参数（蒂勒模量）Φ0 和参数 v（孔隙中的浓度和电位之间的关系），可以估算孔隙度对阻抗的影响。讨论了获得这种阻抗的条件。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Electroanalytical Chemistry 化学-电化学

CiteScore

7.80

自引率

6.70%

发文量

912

审稿时长

2.4 months

期刊介绍： The Journal of Electroanalytical Chemistry is the foremost international journal devoted to the interdisciplinary subject of electrochemistry in all its aspects, theoretical as well as applied. Electrochemistry is a wide ranging area that is in a state of continuous evolution. Rather than compiling a long list of topics covered by the Journal, the editors would like to draw particular attention to the key issues of novelty, topicality and quality. Papers should present new and interesting electrochemical science in a way that is accessible to the reader. The presentation and discussion should be at a level that is consistent with the international status of the Journal. Reports describing the application of well-established techniques to problems that are essentially technical will not be accepted. Similarly, papers that report observations but fail to provide adequate interpretation will be rejected by the Editors. Papers dealing with technical electrochemistry should be submitted to other specialist journals unless the authors can show that their work provides substantially new insights into electrochemical processes.