How well does simple RC circuit analysis describe diffuse double layer capacitance at smooth micro- and nanoelectrodes?

Dickinson, Edmund J. F.; Compton, Richard G.

doi:10.1016/j.jelechem.2011.02.016

Cited by 23 publications

(4 citation statements)

References 12 publications

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“…Please note that, despite the lack of redox reactions at the electrodes, a charge transfer resistance must still be included in the circuit modeling since it influences the features of the tail-like impedance at low frequencies. The representation of this EDL part can be made with a variety of approaches including (i) a single capacitor, − (ii) a parallel configuration of a capacitor and a resistor to account for the charge transfer (interfacial) resistance R p , ,, and (iii) a parallel configuration of R p and a constant phase element (CPE) to account for a capacitor with a distribution of time constants on the electrode surface. − In this work, we use a modification of the latter approach. It should be noted that since both electrodes in the measurement cell are similar, we assume both have the same impedance response.…”

Section: Resultsmentioning

confidence: 99%

Structure of the Electrical Double Layer Revisited: Electrode Capacitance in Aqueous Solutions

2020

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The structure of the electrical double layer at the interface of planar electrodes and aqueous solutions is investigated. Electrical impedance spectroscopy is used to measure the impedance of aqueous solutions of sodium chloride and two different surfactants over a wide range of concentrations. The electrode capacitance is directly inferred from the admittance spectra, as well as by regression of the impedance spectra to an equivalent circuit. It is found that the electrode capacitance remains on the same order of magnitude over the entire range of investigated concentrations. This is contradictive to the predictions of the Gouy-Chapman-Stern theory which predicts that at low concentrations, the electrode capacitance should be determined by the diffuse layer. It is concluded that the Stern layer capacitance always dominates the electrode capacitance, even at very low concentrations, and the establishment of a diffuse layer capacitance 1 requires an ionic strength of around 1 mM.

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Section: Resultsmentioning

confidence: 99%

Structure of the Electrical Double Layer Revisited: Electrode Capacitance in Aqueous Solutions

2020

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“…Approaches for evaluating the integrity of and defects in the seal at electrode-insulator interfaces have included cyclic voltammetry (CV) 2,35,47,53,87 and electrochemical impedance spectroscopy (EIS). [88][89][90][91][92] Investigations that quantify charging current at microelectrodes using CV at different scan rates in aqueous supporting electrolyte at the gold-insulator interfaces have been reported for Si 3 N 4 , 93 glass, 47 polyimide, 94 Teflon TM , 47 and Tefzel TM . 95 The interfaces between other metals like platinum, silver, and nickel with Teflon TM have also been considered.…”

Section: R C U Dmentioning

confidence: 99%

Modeling Charging Current Dynamics at Microelectrodes and their Interfaces with Electrolyte and Insulators with a Focus on Microfabricated Gold Microband Electrodes on an SU-8 Substrate

Abrego Tello,

Lotfi Marchoubeh,

Fritsch

2024

J. Electrochem. Soc.

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The suitability of electrochemical methods for quantitative measurements at microdevices is influenced by the relatively large electrode-insulator interface-to-electrode area ratio, greatly impacting charging dynamics due to interactions among electrolyte and conductor/insulator materials. The resulting charging current can overwhelm the current from redox chemistry. The device studied here features a 70-µm×100-µm electroactive window, hosts gold coplanar microband electrodes, and is insulated by SU-8, which serves as both overlayer and substrate. The overlayer defines the electroactive length and isolates the leads of the electrodes from the sample solution. Cyclic voltammetry in 0.10 M KCl yields unexpected, nonlinear dependence of current on scan rate, which can be explained with two empirical approaches. The first employs an equivalent circuit, involving leakage resistance and double-layer capacitance in parallel, to address both background processes and electrode imperfections as a function of scan rate. The second associates the enhanced current to a changing-chargeable area resulting from interface irregularities. Prior publications on alternative conductor-insulator materials are benchmarked in this study. The comparison of the materials shows that charging dynamics for devices made with SU-8 lead to more favorable electrochemical performance than for those constructed with glass, epoxy, and silicon nitride, and under certain circumstances, polyimide and Tefzel.

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“…1) that describes an electrolyte solution contacted by two electrodes. A more thorough description of this system and related equations can be found in [28]. In the Laplace domain, the voltage at the node V D in Fig.…”

Section: A Simple Equivalent Circuit Modelmentioning

confidence: 99%

“…C SL is assumed constant in the analytical model used to interpret the FEM simulation, while C dl is calculated numerically by simply integrating the charge in the diffuse layer (as obtained from the PNP simulation) and dividing by the voltage drop between the Stern Layer and the node V D . In this way, we extend the validity of the equivalent circuit to an applied potential much larger than the thermal voltage [28]. Assuming a 1D geometry for the sake of a simpler notation, the diffuse layer capacitance per unit area reads:…”

Section: A Simple Equivalent Circuit Modelmentioning

confidence: 99%

Reproducing capacitive cyclic voltammetric curves by simulation: When are simplified geometries appropriate?

Mele

Verardo²,

Palestri³

2022

Electrochemistry Communications

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How well does simple RC circuit analysis describe diffuse double layer capacitance at smooth micro- and nanoelectrodes?

Cited by 23 publications

References 12 publications

Structure of the Electrical Double Layer Revisited: Electrode Capacitance in Aqueous Solutions

Structure of the Electrical Double Layer Revisited: Electrode Capacitance in Aqueous Solutions

Modeling Charging Current Dynamics at Microelectrodes and their Interfaces with Electrolyte and Insulators with a Focus on Microfabricated Gold Microband Electrodes on an SU-8 Substrate

Reproducing capacitive cyclic voltammetric curves by simulation: When are simplified geometries appropriate?

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