DIFFERENTIAL ANALYSIS OF THE IMPEDANCE IN NON-STATIONARY INTERFACES AND THE SIGNIFICANCE OF THE RELATED GENERALIZED FUNCTIONS

Carleane Patrícia da Silva Reis; ALDO MATTHAEUS CUTRIM GOMES; Françoise Toledo Reis; Maria Luisa Sartorelli

Paper Title

Authors

Carleane Patrícia da Silva Reis
ALDO MATTHAEUS CUTRIM GOMES
Françoise Toledo Reis
Maria Luisa Sartorelli

Modality

Pôster

Subject area

Síntese e caracterização de materiais

Publishing Date

12/12/2023

Country of Publishing

Brasil

Language of Publishing

Inglês

Paper Page

https://www.even3.com.br/anais/workshop-do-ineo-2023/613219-differential-analysis-of-the-impedance-in-non-stationary-interfaces-and-the-significance-of-the-related-generaliz

ISBN

978-65-272-0088-8

Keywords

Electrochemical impedance spectroscopy (EIS); Constant-phase element (CPE); reactive electrochemical systems; Fractional-order functions

Summary

The great diversity of size and mobilities of ionic and electronic charge carriers, combined with the high electric fields observed in the electrode/electrolyte interfaces, provide a wide range of properties to be explored in technological devices, from (bio)sensors and storage energy devices to catalysts. From the point of view of a transit charge submitted to an alternating electric field, all processes reduce to two possibilities: either the charge is accumulated in the interface or it is transferred, which is translated either as a capacitance or a resistance, which could be easily quantified by impedance measurements. Nevertheless, the extraction of the these parameters requires the interpretation of the impedimetric response of the interface through the use of electrical equivalent circuit models (EECs). The finite size of the interfaces, as well as the parasitic capacitances of the electrolytic cell and the unavoidable heterogeneities of real systems causes a distribution of characteristic times, leading to frequency-dependent resistance and capacitance [1]. The frequency dispersion compromises the comprehension of the related phenomena and their exploitation in technological devices. The differential analysis of the impedance in the frequency domain (gpe method) enables the model-free extraction of resistance and capacitance values of electrochemical systems, without frequency dispersion [2]. Starting from the mathematical description of a constant phase element (CPE) and its connection to the capacitance of a distributed system, generalized functions of fractional order are defined: Alpha, Kappa and Omega. These functions allow one to follow the real-time evolution of reactive electrochemical systems, unlike the traditional analysis method, which is restricted to stationary interfaces. The interface capacitance results from the product of the generalized functions. In this context, this work will demonstrate the physical meaning of each of those functions, by applying the gpe analysis to impedance spectra measured in classical interfaces, such as n-Si(100)/electrolyte and Au/electrolyte. As an example, we will show that the gpe analysis of impedance measurements performed in hydrogen-terminated n-Si(100) in aqueous 100 mM Na2SO4 electrolyte, as a function of an anodic staircase potential that goes from accumulation to deep depletion revealed, through a well defined minima in the Alpha function, the presence of a fast surface reaction occurring in the accumulation regime, which could be ascribed to an electron-hole recombination, thanks to the fitting of the experimental C-V curve to the expected behavior of a pristine semiconductor electrode. In another example, we will show that, for an Au electrode in NaOH electrolyte, the measured Alpha function, as a function of the applied potential, displays two minima at high frequencies, which helps to localize the point of zero charge. Moreover, it will be shown that, for this simple system, the Omega function retrieves a dispersionless value for the electrolyte resistance. [1] A. Lasia, in Electrochemical Impedance Spectroscopy and Its Applications (Springer New York, New York, NY, 2014). [2] M. L. Sartorelli et al., Model-Free Capacitance Analysis of Electrodes with a 2D+1D Dispersion of Time Constants, Electrochimica Acta 390 (2021) p. 138796.

Title of the Event: Workshop do INEO 2023
City of the Event: Nazaré Paulista
Title of the Proceedings of the event: Anais do Workshop INEO 2023
Name of the Publisher: Even3
Means of Dissemination: Meio Digital

How to cite

REIS, Carleane Patrícia da Silva et al.. DIFFERENTIAL ANALYSIS OF THE IMPEDANCE IN NON-STATIONARY INTERFACES AND THE SIGNIFICANCE OF THE RELATED GENERALIZED FUNCTIONS.. In: Anais do workshop INEO 2023. Anais...Nazaré Paulista(SP) Hotel Estância Atibainha, 2023. Available in: https//www.even3.com.br/anais/workshop-do-ineo-2023/613219-DIFFERENTIAL-ANALYSIS-OF-THE-IMPEDANCE-IN-NON-STATIONARY-INTERFACES-AND-THE-SIGNIFICANCE-OF-THE-RELATED-GENERALIZ. Access in: 17/04/2025