Gabrielli C, Keddam M, Portail N, Rousseau P, Takenouti H, Vivier V
UPR 15 du CNRS, Laboratoire Interfaces et Systèmes Electrochimiques, Université Pierre et Marie Curie, 4, place Jussieu, case courrier 133, 75252 Paris, Cedex 05, France.
J Phys Chem B. 2006 Oct 19;110(41):20478-85. doi: 10.1021/jp063055h.
Electrochemical impedance spectroscopy experiments were performed on a microdisk electrode in a thin-layer cell using a scanning electrochemical microscope for controlling the cell geometry. Experimental data showed that when the thin-layer thickness diminished, an additional low-frequency response appeared. It was ascribed to the radial diffusion of the electroactive species and was strongly dependent on the thin-layer dimensions (both thickness and diameter). Moreover, the numerical simulation of the impedance diagrams by finite element method calculations confirmed this behavior. An equivalent circuit based on a Randles-type circuit was proposed. Thus, the diffusion was described by introducing two electrical elements: one for the spherical diffusion and the other for the radial contribution. A nonlinear Simplex algorithm was used, and this circuit was shown to fit the impedance diagrams with a good accuracy.
使用扫描电化学显微镜在薄层电池中的微盘电极上进行电化学阻抗谱实验，以控制电池的几何形状。实验数据表明，当薄层厚度减小时，会出现额外的低频响应。这归因于电活性物质的径向扩散，并且强烈依赖于薄层尺寸（厚度和直径）。此外，通过有限元法计算对阻抗图进行数值模拟证实了这种行为。提出了一种基于兰德斯型电路的等效电路。因此，通过引入两个电学元件来描述扩散：一个用于球形扩散，另一个用于径向贡献。使用了非线性单纯形算法，并且该电路被证明能够很好地拟合阻抗图。
