Evaluation of impedance spectra of ionic-transport materials by a random-walk approach considering electrode and bulk response

Abstract

Analysis of impedance spectra by a random-walk approach is proposed for the study of ionic-transport materials with a silver-containing chalcogenide glass as a case example. Through a full analysis of complex impedance spectra including the electrode polarization effect, some important physical parameters, such as the number of mobile ions in bulk and interface regions, the diffusion coefficient, etc., are extracted without using the conventional equivalent electric circuit analysis. A detailed discussion on electrode polarization, which is highly dependent on signal amplitude, is also presented.

Ionic conductivity study of LiI-Ga2S3-GeS2 chalcogenide glasses using a random-walk approach

“…From comparison with the Ag-doped glasses studied previously, we observed that the electrode polarization is shifted towards the lower frequencies more than one order of magnitude [18]. The electrode polarization phenomenon gives a hump in the low frequency region in the σ 2 vs ω plot [17]. Therefore this hump was expected to be seen also in our case in Fig.…”

“…Therefore, in the present article we will analyze the IS data using the RW model and the obtained results will be compared with the results obtained by the EEC method. The details about the RW model, how it works, and mathematical basics were published in our previous articles [15][16][17][18]. The complex resistivity plot for the glasses at x = 10, 15 and 20 is shown in Fig.…”

“…To overcome the above mentioned limitations of the EEC method and understand the dynamics of mobile ions, we have developed recently a way of IS data analysis called a random-walk (RW) model [16][17][18]. The RW model can give the physical parameters such as number of mobile ions (N ions ), diffusion coefficient (D), and maximum hopping time of ions (τ max ) in the bulk properties of the material and at the electrode interface quantitatively without using any EEC.…”

Measurement of the impedance of aqueous solutions of KCl: An analysis using an extension of the Poisson-Nernst-Planck model

“…The spectra of the real and imaginary parts of the impedance, representing the resistance and reactance of the cell in series representation, are then analyzed by means of appropriate theoretical models. [2][3][4][5] In the case of electrolytic solutions, the dispersion of the impedance is due, up to a few MHz, to the ions present in the solution. The redistribution of the ions inside the sample is well described by the equation of continuity for the ions and the equation of Poisson, relating the actual electric potential to the bulk density of ions, together with the Einstein-Smolukowsky relation.…”

New Approach of Data Mining from the Complex Impedance Plane: Parameters You Have Always Wanted to Have

“…1 provides an overview of glasses used in the present study based on combination of GeS 2 , Ga 2 S 3 , AgI and Ag. Details of the glass synthesis have been already published (6). It is noteworthy that the exact atom percentages of Ag measured by EDX are very close to percentages derived from nominal compositions.…”