Becchi M, Avendaño C, Strigazzi A, Barbero G
Dipartimento di Fisica del Politecnico and I.N.F.M., Corso Duca degli Abruzzi, 24, 10129 Torino, Italy.
J Phys Chem B. 2005 Dec 15;109(49):23444-9. doi: 10.1021/jp044443r.
We discuss the influence of the ions dissolved in a liquid on the impedance spectroscopy of a cell. Our analysis is performed in the small-voltage regime, where the actual bulk density of ions is only slightly perturbed by the external electric field. In this framework, we show that the presence of the ions can be taken into account by a surface density of charge. The agreement between the theoretical prediction, on the basis of the assumption that the ionic mobility is frequency independent, and the experimental data for the real and imaginary parts of the impedance is fairly good for frequencies larger than 100 Hz. In the low-frequency range, the agreement of the theory with the experiment is rather poor. In this region, the experimental data can be successfully fitted by introducing the impedance of the metal-electrolyte interface, which is accurately represented by Zi = w(i omega)(-nu), where w and nu are two constants, with 0 < nu < 1. From the analysis of the experimental data, we determine w and nu. The theoretical predictions of our model are in good agreement with the experimental data in the investigated frequency range.
我们讨论了溶解在液体中的离子对电池阻抗谱的影响。我们的分析是在小电压 regime 下进行的，在该 regime 中，离子的实际体密度仅受到外部电场的轻微扰动。在此框架下，我们表明离子的存在可以通过表面电荷密度来考虑。基于离子迁移率与频率无关的假设的理论预测与阻抗实部和虚部的实验数据之间的一致性对于频率大于100 Hz时相当好。在低频范围内，理论与实验的一致性相当差。在该区域，通过引入金属 - 电解质界面的阻抗可以成功拟合实验数据，该阻抗由Zi = w(iω)(-ν)精确表示，其中w和ν是两个常数，0 < ν < 1。通过对实验数据的分析，我们确定了w和ν。我们模型的理论预测与所研究频率范围内的实验数据吻合良好。
