APPLICATION OF THE GENERALIZED PHASE ELEMENT METHOD TO ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY MEASUREMENTS IN POLYANILINE ELECTRODES.

Arthur da Silva Zimermann (IC); UFSC; Carleane Patrícia da Silva Reis; Maria Luisa Sartorelli; Françoise Toledo Reis

Paper Title

Authors

Arthur da Silva Zimermann (IC); UFSC
Carleane Patrícia da Silva Reis
Maria Luisa Sartorelli
Françoise Toledo Reis

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-2023/612657-application-of-the-generalized-phase-element-method-to-electrochemical-impedance-spectroscopy-measurements-in-pol

ISBN

978-65-272-0088-8

Keywords

electrochemical impedance spectroscopy, generalized phase element, time constant distribution, capacitance dispersion, polyaniline

Summary

Electrochemical impedance spectroscopy (EIS) is a powerful technique to probe electrochemical phenomena occurring at the electrode/electrolyte interface, since it allows to access the dynamics of the charge transfer/accumulations processes, under specific energetic conditions, usually expressed in terms of equivalent resistances and capacitances. Also, due to the great diversity of size and mobilities of ionic species as compared to electrons, the related characteristics can be observed separately in the frequency-domain [1]. Nevertheless, the finite size of interfaces and the heterogeneities of real systems lead to a distribution of characteristic times, originating frequency dispersion of both resistance and capacitance, which affects the characterization of a variety of devices, such as supercapacitors, rechargeable batteries, solar cells and sensors [2]. In order to extract information from impedance spectra, we have proposed a method based on the concept of a generalized phase element (gpe), to study electrochemical systems presenting a dispersion of time constants [3]. The gpe method relies on a differential analysis of impedance in the frequency-domain, which enables the extraction of dispersionless values of capacitance and resistance without the use of electrical equivalent circuit (EECs) analogues. The gpe analysis generate a series of frequency dependent indicators or functions (as opposed to the analysis that describes impedance spectra using constant phase elements), which can be examined in terms of their evolution as a function of the applied potential. In order to demonstrate the gpe method capabilities, we have prepared HNO3 doped polyaniline (PANI) electrodes electrochemically, under potentiostatic conditions. Indium tin oxide (ITO) was used as substrate for the lectropolymerized PANI. The electrochemical characterization was performed in aqueous HNO3 electrolytes in a three-electrode configuration, with a saturated calomel electrode (SCE) in a Luggin capillary as a reference and a platinum foil as a counter-electrode. Besides the traditional cyclic voltammetry characterization, the PANI electrodes were submitted to sequential EIS measurements under a staircase potential scan ranging from -0,05 to 0,6 V/SCE, with 20 mV steps. The frequency pattern exhibited by the generalized phase element as a function of the applied potential suggests the presence of two different charge carriers, with distinct mobilities. The generalized capacitance, on the other hand, exhibits two distinct plateaus. The high frequency plateau, which is around 15 microF/cm2 does not change with film thickness and is ascribed to a Schottky barrier at the interface ITO/PANI. The low frequency plateau, on the order of 0.1 F/cm2, increases linearly with the thickness of the PANI layer. However, it is not a pseudo-capacitance, since it does not display frequency dispersion. Therefore, it must be related to the electrical double layer that surrounds the individual PANI fibers, and can be used as a direct indicator of the wetted area of the electroactive material. Work supported by CNPq, CAPES and INEO. References: [1] M. E. Orazem and B. Tribollet, in Electrochemical Impedance Spectroscopy (Wiley, New Jersey, USA, 2008). [2] A. Lasia, in Electrochemical Impedance Spectroscopy and Its Applications (Springer, New York, USA, 2014) [3] 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

UFSC, Arthur da Silva Zimermann (IC); et al.. APPLICATION OF THE GENERALIZED PHASE ELEMENT METHOD TO ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY MEASUREMENTS IN POLYANILINE ELECTRODES... 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-2023/612657-APPLICATION-OF-THE-GENERALIZED-PHASE-ELEMENT-METHOD-TO-ELECTROCHEMICAL-IMPEDANCE-SPECTROSCOPY-MEASUREMENTS-IN-POL. Access in: 19/04/2025