Theory of the electrochemical impedance of macrohomogeneous porous electrodes

Paasch, G.; Micka, K.; Gersdorf, Peter

doi:10.1016/0013-4686(93)85083-b

Cited by 195 publications

(165 citation statements)

References 21 publications

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“…A major assumption adopted (as in the classical theory of porous electrodes 16,18 ) is that transport in the more resistive phase is driven by the gradient of the electrical potential φ 1 . From Figure 3, the following equation is easily deduced which is simply the statement of Ohm's law in channel 1.…”

Section: Impedance Of the Two-channel Transmission Linementioning

confidence: 99%

Doubling Exponent Models for the Analysis of Porous Film Electrodes by Impedance. Relaxation of TiO₂ Nanoporous in Aqueous Solution

et al. 2000

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The paper is concerned with the small signal ac impedance of porous film electrodes in contact with solution. An overview is presented of the standard transmission line model with two transport channels and a crosswise element. The simplest configurations are discussed: a single resistance in one of the channels, and either an interfacial capacitor or a RC transfer circuit at the pore's wall. The resulting relaxation functions are classified in terms of two characteristic frequencies: one for coupled transport and interfacial polarization and another one for the interfacial reaction. Subsequently, these models are extended in order to describe porous electrodes where the interfacial polarization displays complex properties, i.e., frequency dispersion. The capacitive element is described by a constant-phase element (CPE), and it is shown that the fractionary exponent provides an additional and measurable degree of freedom in the parameter space of the relaxation function, whose determination can be exploited as a supplementary tool for analysis. The analysis of impedance measurements of TiO 2 nanoporous photoelectrodes in negative bias voltage shows that the suggested approach is capable of identifying two characteristic relaxation frequencies in a frequency-resolved measurement on this system.

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Section: Impedance Of the Two-channel Transmission Linementioning

confidence: 99%

Doubling Exponent Models for the Analysis of Porous Film Electrodes by Impedance. Relaxation of TiO₂ Nanoporous in Aqueous Solution

et al. 2000

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“…Beginning essentially with the work of de Levie [20,22,23], a large number of various models have been developed [1,18,19,21,24,25] to theoretically describe the experimental behaviour of the porous electrodes. A very important direction is the investigation of the influence of the pore geometry on the data of electrical impedance spectroscopy (EIS) [24,25].…”

Section: Introduction and Theoretical Backgroundmentioning

confidence: 99%

“…A circuit element with the distributed characteristic can not be exactly expressed as a combination of a finite number of ideal circuit elements, except in certain limiting cases. The distributed characteristic results mainly from the two origins [1,6,[18][19][20][21][22][23][24][25].…”

Section: Introduction and Theoretical Backgroundmentioning

confidence: 99%

“…Some authors used simple modifications of the classical Randles-Frumkin-Melik-Gaikazyan equivalent circuits, involving a constant phase element or Warburg diffusion impedance modified according to the boundary conditions [1,21,[26][27][28][29][30], as well as the branched transmission line equivalent circuits [1,18,31]. Paasch et al [21] developed a theory for macroscopically homogeneous porous electrode, where the three main processes are considered: (a) ionic conductivity in the porous electrolyte and electronic conductance in the electrode (solid) phase; (b) charging the double layer at the solid | liquid interface; and (c) the simple charge transfer reaction (ctr.) at the interface.…”

Section: Introduction and Theoretical Backgroundmentioning

confidence: 99%

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Electrochemical Properties of Nanoporous Carbon Electrodes

Lust¹,

Nurk²,

Janes³

et al. 2002

Condens. Matter Phys.

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Electrical double layer and electrochemical characteristics at the nanoporous carbon | (C 2 H 5 ) 4 NBF 4 + acetonitrile interface have been studied by the cyclic voltammetry and impedance spectroscopy methods. The value of zero charge potential (0.23 V vs. SCE in H 2 O), the region of ideal polarizability and other characteristics have been established. Analysis of complex plane plots shows that the nanoporous carbon | x M (C 2 H 5 ) 4 NBF 4 + acetonitrile interface can be simulated by the equivalent circuit, in which the two parallel conduction parts in the solid and liquid phases are interconnected by the double layer capacitance in parallel with the complex admittance of hindered reaction of the charge transfer process. The values of the characteristic frequency depend on the electrolyte concentration and on the electrode potential, i.e. on the nature of ions adsorbed at the surface of nanoporous carbon electrode.

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“…This model works well to describe flat and/or roughened electrodes, but in the case of porous ones as, for example, conducting polymers, another type of interpretation including the porosity description is necessary. In the case of porous materials where the pores are deep enough to be considered as channels in the material, the impedance of the electrolyte in the pores, the impedance of the material itself, and the impedance of the interface between them have to be considered [25,26]. There are two limiting cases for two-media systems: (i) the impedance of the two media are comparable, and (ii) the impedance of one medium is much larger than the other one, which can, hence, be neglected.…”

Section: Introductionmentioning

confidence: 99%

Properties improvement of poly(o-methoxyaniline) based supercapacitors: experimental and theoretical behaviour study of self-doping effect

Gonçalves

Christinelli

Trench

et al. 2017

Electrochimica Acta

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ABSTRACT:Conducting polymers (CP) are very versatile materials with important properties due to their unique structure, including redox behaviour upon electrochemical polarization. Supercapacitors are among the devices in which CP show a promising performance due to their large specific capacitance. However, the major drawback of these materials is their low durability, which is an inbuilt process caused by ion intercalation, a side effect of the redox process. A viable strategy to increase CP stability is, therefore, the inhibition of the ion intercalation/de-intercalation process. Several strategies have been proposed to minimize this effect, among them self-doping. Self-doping makes the redox process mass-transport independent, decreasing the response time and increasing durability. With this purpose, this work have described the synthesis of layer-by-layer films (LBL) of poly(omethoxyaniline)/poly(3-thiopheneacetic acid) (POMA/PTAA) and contributes to understand how the redox process leads to premature aging, and how self-doping minimizes this problem. The main techniques of characterisation used were electrochemical impedance spectroscopy (EIS) experiments and density functional theory (DFT) calculations. EIS provides important information about the electrochemical behaviour, while DFT calculations allowed to characterize, at the molecular level, the changes in the material structure. The association of both techniques helped to understand how self-doping improves the POMA properties. DFT calculations showed that in the layer-by-layer (LBL) films, the twisting of the polymer chain due to the oxidation is 12% less while the chain shortening is 5% compared with films prepared POMA by casting. The EIS data showed the effect of these molecular changes in the structure; the swelling of the LBL films is 50% less than cast ones. These observations are important because the PTAA layer acts beyond a chargecompensator, working as a backbone structure that mechanically stabilize the POMA layer, leading to an increase in the durability, and improving the electrochemical properties.

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Theory of the electrochemical impedance of macrohomogeneous porous electrodes

Cited by 195 publications

References 21 publications

Doubling Exponent Models for the Analysis of Porous Film Electrodes by Impedance. Relaxation of TiO₂ Nanoporous in Aqueous Solution

Doubling Exponent Models for the Analysis of Porous Film Electrodes by Impedance. Relaxation of TiO₂ Nanoporous in Aqueous Solution

Electrochemical Properties of Nanoporous Carbon Electrodes

Properties improvement of poly(o-methoxyaniline) based supercapacitors: experimental and theoretical behaviour study of self-doping effect

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Theory of the electrochemical impedance of macrohomogeneous porous electrodes

Cited by 195 publications

References 21 publications

Doubling Exponent Models for the Analysis of Porous Film Electrodes by Impedance. Relaxation of TiO2 Nanoporous in Aqueous Solution

Doubling Exponent Models for the Analysis of Porous Film Electrodes by Impedance. Relaxation of TiO2 Nanoporous in Aqueous Solution

Electrochemical Properties of Nanoporous Carbon Electrodes

Properties improvement of poly(o-methoxyaniline) based supercapacitors: experimental and theoretical behaviour study of self-doping effect

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Product

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Doubling Exponent Models for the Analysis of Porous Film Electrodes by Impedance. Relaxation of TiO₂ Nanoporous in Aqueous Solution

Doubling Exponent Models for the Analysis of Porous Film Electrodes by Impedance. Relaxation of TiO₂ Nanoporous in Aqueous Solution