Electrochemical Impedance Spectroscopy and its Applications

Lasia, Andrzej

doi:10.1007/0-306-46916-2_2

Cited by 833 publications

(907 citation statements)

References 162 publications

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“…Hence, the time-derivative is described as below. [1] eq (1) The first term on the right side is known as the polarization resistance, R p , which tells the rate of change transfer at the electrified interface as described by eq(2) [13], while the rest part tells the rate of mass transfer through the diffusion layer. eq (2) k f and k r are rate constants for reduction and oxidation reactions, α transfer coefficient, n the number of electron transferred, F faradaic constant, R gas constant and T temperature.…”

Section: Theories and Discussionmentioning

confidence: 99%

Effects of the Polarization Resistance on Cyclic Voltammograms for an Electrochemical-Chemical Reaction

Chang

2015

Journal of Electrochemical Science and Technology

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Here I report an electrochemical simulation work that compares voltammetric current and resistance of a complex electrochemical reaction over a potential scan. For this work, the finite element method is employed which are frequently used for voltammetry but rarely for impedance spectroscopy. Specifically, this method is used for simulation of a complex reaction where a heterogeneous faradaic reaction is followed by a homogeneous chemical reaction. By tracing the current and its polarization resistance, I learn that their relationship can be explained in terms of rate constants of charge transfer and chemical change. An unexpected observation is that even though the resistance is increased by the rate of the following chemical reaction, the current can be increased due to the potential shift of the resistance made by the proceeding faradaic reaction. This report envisions a possibility of the FEM-based resistance simulation to be applied to understand a complex electrochemical reaction. Until now, resistance simulations are mostly based on equivalent circuits or complete mathematical equations and have limitations to find proper models. However, this method is based on the first-principles, and is expected to be complementary to the other simulation methods.

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Section: Theories and Discussionmentioning

confidence: 99%

Effects of the Polarization Resistance on Cyclic Voltammograms for an Electrochemical-Chemical Reaction

Chang

2015

Journal of Electrochemical Science and Technology

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“…The element represented by W s is called a generalized finite-length Warburg element for transmissive [15,16]. This element simulates the process of diffusion of ions formed on one electrode to the opposite electrode and their reduction on it.…”

Section: X-ray and Thermal Analysis Of Bi 5 Nb 3-3х Cr 3х O 15-δmentioning

confidence: 99%

“…3). According to the electrochemical impedance theory [15], the parameter R corresponds to the energy loss during diffusion of ions and it is expressed in Ohms. The ionic resistance is responsible for energy losses during the ion drift (moving in an electric field).…”

Section: Tanh ( ) ( )mentioning

confidence: 99%

Electrical properties of Bi5Nb3–3xCr3xO15–δ characterized by impedance spectroscopy

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Belyaeva

et al. 2017

LoM

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The majority of bismuth-containing oxide compounds with layered perovskite-like structure are ferroelectric with high Curie temperatures. Bismuth niobate Bi 5 Nb 3 O 15 belongs to the group of layered perovskite-like compounds and is characterized by relaxation-like ferroelectric behavior. Previous studies have shown that bismuth niobate forms a limited range of solid solutions containing atoms of transition elements. In this connection, we studied the influence of the heterovalent substitution of niobium by chromium atoms on the phase transition and electrophysical properties of bismuth niobate. The electrical properties of the polycrystalline samples of bismuth niobate Bi 5 Nb 3 O 15 and chromium-containing solid solutions Bi 5 Nb 3-3х Cr 3х O 15-δ (х ≤ 0.08) were studied using impedance spectroscopy. Bismuth niobate is crystallized in tetragonal syngony; the solid solutions with х ≥ 0.04 have a monoclinic distortion of the tetragonal structure. We did not find any phase transitions significantly changing electrical properties of the oxide materials Bi 5 Nb 3 O 15 and Bi 5 Nb 3-3х Cr 3х O 15-δ (х ≤ 0.08) in the temperature range of 350 -600°С; this can be caused by relaxation character of dielectric polarization and blurring of the phase transition. The equivalent circuits were developed for Bi 5 Nb 3 O 15 and the solid solutions. The circuits consisted of the resistors and two elements for space-distributed polarization. The accuracy of the equivalent circuits was checked by the agreement between the experimental and calculated values. The Bi 5 Nb 3-3х Cr 3х O 15-δ samples exhibited dielectric properties with extremely low conductivity at temperatures under 350°С. At the higher temperature, the materials demonstrated semiconducting properties with the activation energy of the conductivity of ~0.6 eV. The performed study allows us to conclude about the mixed electronic-ionic character of conductivity in the Bi 5 Nb 3-3х Cr 3х O 15-δ .

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“…The deviation from 90°at low frequencies cannot be explained by a pure capacitance. The use of a constant phase element (CPE) is more appropriate in this case to simulate non-ideal conditions that are typically observed for porous electrodes [26,27]. Using the graphical method and Eq.…”

Section: R P Values Before and After Dmfc Testing: ''The H 2 / N 2 Mementioning

confidence: 99%

DMFC electrode preparation, performance and proton conductivity measurements

et al. 2008

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A method that involves stenciling electrodes using dry powders for fuel cells is described and compared to anodes and cathodes prepared by the traditional spraying method using catalyst inks. Methods to determine the proton conductivity of the DMFC anode layer are also discussed. The stenciling method allows for the preparation of highly reproducible membrane electrode assemblies (MEAs) utilizing little waste material. MEAs can be prepared in a controlled manner using the stenciling technique. The resulting morphology of the as-prepared electrodes is observed to be dependent on the preparation method, while the thickness of the once hot-pressed catalyst layers appears to be independent of the preparation method. Stenciled anodes of the same catalyst loading were found to show a lower proton resistance (R p ) than sprayed anodes. However, the lower R p value was not sufficient to result in a measurable increase in the performance of a direct methanol fuel cell (DMFC); as in fact, the average steady-state DMFC performance was found to be the same using sprayed or stenciled electrodes. The DMFC performance was found to be strongly dependent on the Nafion content and large increases in the Nafion content were needed to increase the DMFC performance measurably. Even though thick electrodes were prepared in this work, the R p values of the stenciled anodes were found to be comparable to results reported in the literature for much thinner electrodes made using high metal catalyst loadings on carbon. This observation is most probably due to the higher Nafion content used in this work.

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Electrochemical Impedance Spectroscopy and its Applications

Cited by 833 publications

References 162 publications

Effects of the Polarization Resistance on Cyclic Voltammograms for an Electrochemical-Chemical Reaction

Effects of the Polarization Resistance on Cyclic Voltammograms for an Electrochemical-Chemical Reaction

Electrical properties of Bi5Nb3–3xCr3xO15–δ characterized by impedance spectroscopy

DMFC electrode preparation, performance and proton conductivity measurements

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