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Journal articles on the topic 'Butler-Volmer equation'

Author: Grafiati
Published: 4 June 2021
Last updated: 25 January 2023

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1

Dreyer, Wolfgang, Clemens Guhlke, and Rüdiger Müller. "A new perspective on the electron transfer: recovering the Butler–Volmer equation in non-equilibrium thermodynamics." Physical Chemistry Chemical Physics 18, no. 36 (2016): 24966–83. http://dx.doi.org/10.1039/c6cp04142f.

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Butler–Volmer equations can be recovered from a complete non-equilibrium thermodynamic model by application of asymptotic analysis. Thereby we gain insight into the coupling of different physical phenomena and can derive Butler–Volmer equations for very different materials and electrochemical systems.
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2

Xu, Aoni, Chaofang Dong, Angjian Wu, Ruixue Li, Li Wang, Digby D. Macdonald, and Xiaogang Li. "Plasma-modified C-doped Co3O4 nanosheets for the oxygen evolution reaction designed by Butler–Volmer and first-principle calculations." Journal of Materials Chemistry A 7, no. 9 (2019): 4581–95. http://dx.doi.org/10.1039/c8ta11424b.

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Electrocatalysts serving in electrochemical cells differ from general chemical catalysts by way of their special double-layer structure and a rarely discussed interface potential drop as described by the Butler–Volmer (BV) equation.
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3

Baschuk, Jeffrey J., Andrew M. Rowe, and Xianguo Li. "Modeling and Simulation of PEM Fuel Cells With CO Poisoning." Journal of Energy Resources Technology 125, no. 2 (June 1, 2003): 94–100. http://dx.doi.org/10.1115/1.1538186.

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A polymer electrolyte membrane (PEM) fuel cell is analyzed by applying the conservation principle to the electrode backing, catalyst layers and polymer electrolyte. The conservation equations used are the conservation of species, momentum and energy, with the Nernst-Planck equation used for the electrolyte. Oxygen reduction at the cathode is modeled using the Butler-Volmer equation while the adsorption, desorption and electro-oxidation of hydrogen and CO at the anode are modeled by the Tafel-Volmer and “reactant-pair” mechanism, respectively. Temperature variations within the cell are minimized by decreasing current density or increasing temperature. An increase in pressure increases the cell voltage at low current density, but decreases the cell voltage at high current density. The electrochemical kinetics model used for the adsorption, desorption and electro-oxidation of hydrogen and CO is validated with published, experimental data.
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4

Mitic, Vojislav, Goran Lazovic, Dragan Djordjevic, Maja Stankovic, Vesna Paunovic, Nenad Krstic, and Jelena Manojlovic. "Butler-Volmer current equation and fractal nature correction in electrochemical energy." Thermal Science, no. 00 (2020): 232. http://dx.doi.org/10.2298/tsci200117232m.

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The Global Energy Crisis necessitated improving research into new, renewable and alternative energy sources. Due to that, our focus is on the area of some phenomena and applications where different synthetic methods and microstructure property optimization achieved significant improvement in the electro physical properties of output materials and components. This is especially important for higher energy efficiency and electricity production (batteries and battery systems, fuel cells, and hydrogen energy).The improvement of energy storage tank capacity is one of the most important development issues in the energy sphere too. It?s because of this very promising research and application area that we are expanding the knowledge on these phenomena through fractal nature analysis. So, the results obtained in the field of electrochemical energy sources, especially in electrolyte development, are taken into account the analysis of fractal nature optimization. Based on the research field of fractal material science, particularly electronic materials, we conducted research in microstructure fractal influence in the area of electrochemistry. We investigated the consolidation parameters of Fe2O3 redox processes. The influence of activation energy, fundamental thermodynamic parameters, and also the fractal correction of electrode surface area through complex fractal dimension with recognized grains and pores, and the Brownian motion of particles is introduced. Finally, the electrochemical Butler-Volmer equation fractalization is obtained. These results practically open new frontiers in electrochemical energy processes performed through the Arrhenius equation within electrolyte bulk and electrode relations and more complete and precise energy generation.
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5

Vijay, Periasamy, and Moses O. Tadé. "Improved approximation for the Butler-Volmer equation in fuel cell modelling." Computers & Chemical Engineering 102 (July 2017): 2–10. http://dx.doi.org/10.1016/j.compchemeng.2016.10.018.

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6

Dickinson, Edmund J. F., and Andrew J. Wain. "The Butler-Volmer equation in electrochemical theory: Origins, value, and practical application." Journal of Electroanalytical Chemistry 872 (September 2020): 114145. http://dx.doi.org/10.1016/j.jelechem.2020.114145.

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7

Magonski, Zbigniew, and Barbara Dziurdzia. "New proposal to the electrical representation of a solid oxide fuel cell." Microelectronics International 34, no. 3 (August 7, 2017): 140–48. http://dx.doi.org/10.1108/mi-12-2016-0092.

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Purpose The aim of this paper is to find the electrical representation of a solid oxide fuel cell (SOFC) that enables the application of typical exploitation characteristics of fuel cells for estimation of fuel cell parameters (for example, exchange current) and easy analysis of phenomena occurred during the fuel cell operation. Design/methodology/approach Three-layer structure of an SOFC, where a thin semi-conducting layer of electrolyte separates the anode from the cathode, shows a strong similarity to typical semiconductor devices built on the basis of P-N junctions, like diodes or transistors. Current–voltage (I-V) characteristics of a fuel cell can be described by the same mathematical functions as I-V plots of semiconductor devices. On the basis of this similarity and analysis of impedance spectra of a real fuel cell, two electrical representations of the SOFC have been created. Findings The simplified electrical representation of SOFC consists of a voltage source connected in series with a diode, which symbolizes a voltage drop on a cell cathode, and two resistors. This model is based on the similarity of Butler-Volmer to Shockley equation. The advanced representation comprises a voltage source connected in series with a bipolar transistor in close to saturation mode and two resistors. The base-emitter junction of the transistor represents voltage drop on the cell cathode, and the base-collector junction represents voltage drop on the cell anode. This model is based on the similarity of Butler-Volmer equation to Ebers-Moll equation. Originality/value The proposed approach based on the Shockley and Ebers-Moll formulas enables the more accurate estimation of the ion exchange current and other fuel cell parameters than the approach based on the Butler-Volmer and Tafel formulas. The usability of semiconductor models for analysis of SOFC operation was proved. The models were successively applied in a new design of a planar ceramic fuel cell, which features by reduced thermal capacity, short start-up time and limited number of metal components and which has become the basis for the SOFC stack design.
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8

Lin, Zhen, Chang Hui Wang, and Yu Liu. "Modeling and Analysis of Static Water Feed Solid Polymer Water Electrolysis Cell." Advanced Materials Research 236-238 (May 2011): 750–54. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.750.

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A simple model specific to static water feed solid polymer electrolyte (SPE) water electrolysis cell is constructed containing Butler-Volmer equation for calculating electrode over potentials, Nernst equation for calculating thermodynamic voltage and water balance equation for solving membrane water content. Based on the model, the water content distribution of the membrane is obtained, and the operating current density limitation is shown. It is indicated that the operating current density limitation of static water feed SPE electrolysis cell is obviously lower than that of normal SPE electrolysis cell.
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9

Fletcher, Stephen, and Thomas Stephen Varley. "Beyond the Butler–Volmer equation. Curved Tafel slopes from steady-state current–voltage curves." Physical Chemistry Chemical Physics 13, no. 12 (2011): 5359. http://dx.doi.org/10.1039/c0cp02471f.

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10

Alvarez-Ramirez, J., J. Vazquez-Arenas, M. González, and Y. Carrera-Tarela. "Non-Linear First-Harmonic Balance to Compute the Electrochemical Impedance of Butler-Volmer Equation." Journal of The Electrochemical Society 165, no. 9 (2018): H517—H523. http://dx.doi.org/10.1149/2.1091809jes.

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11

Shiokawa, Yoshinobu, Tomoo Yamamura, and Kenji Shirasaki. "Energy Efficiency of an Uranium Redox-Flow Battery Evaluated by the Butler–Volmer Equation." Journal of the Physical Society of Japan 75, Suppl (January 2006): 137–42. http://dx.doi.org/10.1143/jpsjs.75s.137.

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12

Vakouftsi, E., G. Marnellos, C. Athanasiou, and Frank A. Coutelieris. "Modeling of Flow and Transport Processes Occurred in a Typical Polymer Electrolyte Membrane Fuel Cell (PEMFC)." Defect and Diffusion Forum 273-276 (February 2008): 87–92. http://dx.doi.org/10.4028/www.scientific.net/ddf.273-276.87.

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In the present work, a three dimensional model examining the fluid flow along with the fundamental transport phenomena occurring in a typical polymer electrolyte fuel cell (PEMFC), i.e. heat transfer, mass transport and charge transfer, has been developed. The flow field was simulated according to the well known Navier-Stokes equations, while the heat transfer was described by the typical conduction/convection equation and the mass transport by the convection/diffusion one. Furthermore, reaction kinetics were studied by the Butler-Volmer equation for the heterogeneous reactions occurring at the porous electrodes. The developed model was numerically solved by using the commercially available CFD package CFD-RC©, which is based on the multi-step finite volume method. The fuel cell performance in terms of velocity, temperature, mass fractions of active compounds and electric field has been investigated as well.
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13

Matsena, Mpumelelo T., and Evans M. N. Chirwa. "Hexavalent chromium-reducing microbial fuel cell modeling using integrated Monod kinetics and Butler-Volmer equation." Fuel 312 (March 2022): 122834. http://dx.doi.org/10.1016/j.fuel.2021.122834.

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14

Shen, X., N. Sinclair, J. Wainright, and R. F. Savinell. "Methods—Analyzing Electrochemical Kinetic Parameters in Deep Eutectic Solvents Using an Extended Butler-Volmer Equation." Journal of The Electrochemical Society 168, no. 5 (May 1, 2021): 056520. http://dx.doi.org/10.1149/1945-7111/ac006a.

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15

Ahmed, Shaik Liyakhath, Sunil Kumar Thamida, and N. Narasaiah. "Novel optimization technique to determine polarization characteristics of a corroding metal." Electrochemical Energy Technology 3, no. 1 (December 20, 2017): 1–8. http://dx.doi.org/10.1515/eetech-2017-0003.

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AbstractPolarization data characterize the corrosion behavior of a metal giving a quick estimate of corrosion current density icorr and corrosion potential Ecorr. These two characteristics determine the corrosion rate and position of the metal in galvanic series. The chosen system for the study is steel (SS304) in NaCl solution. In these studies, icorr and Ecorr of Butler-Volmer equation are obtained by fitting the full expression to experimental current vs potential data unlike the graphical method using Tafelslopes. MATLAB optimization tool box is utilized for this purpose. The novel optimization technique is explained for determining Ecorr and icorr
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16

Dickinson, Edmund J. F., and Gareth Hinds. "The Butler-Volmer Equation for Polymer Electrolyte Membrane Fuel Cell (PEMFC) Electrode Kinetics: A Critical Discussion." Journal of The Electrochemical Society 166, no. 4 (2019): F221—F231. http://dx.doi.org/10.1149/2.0361904jes.

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17

Liu, Sijia, Jiuchun Jiang, Wei Shi, Zeyu Ma, Le Yi Wang, and Hongyu Guo. "Butler–Volmer-Equation-Based Electrical Model for High-Power Lithium Titanate Batteries Used in Electric Vehicles." IEEE Transactions on Industrial Electronics 62, no. 12 (December 2015): 7557–68. http://dx.doi.org/10.1109/tie.2015.2449776.

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18

Li, Hejie, Hongbin Wang, Wenju Ren, Jiangtao Hu, Yuan Lin, and Feng Pan. "A new single-particle model to evaluate the Li-ions diffusion coefficients of LiMn1−xFexPO4." Functional Materials Letters 12, no. 05 (September 17, 2019): 1950071. http://dx.doi.org/10.1142/s1793604719500711.

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It remains a challenge to evaluate the Li-ions diffusion coefficients of LiMn[Formula: see text]FexPO4 due to the presence of two voltage platforms upon charge/discharge. In this paper, a new single-particle model based on Butler–Volmer (BV) equation and one-dimensional diffusion equation is established. Using this model, the cyclic voltammogram curves of LiMn[Formula: see text]FexPO4 single-particle electrodes are successfully fitted and their Li-ion diffusion coefficients in organic electrolyte are obtained. Through analyzing the diffusion coefficients, it is found that the Li-ions diffusion coefficients for both Fe and Mn redox processes in LiMn[Formula: see text]FexPO4 reach the maximum when [Formula: see text]. In addition, the values for oxidation processes are much larger than those for reduction processes.
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19

Herlambang, Yusuf Dewantoro, Kurnianingsih, Anis Roihatin, Totok Prasetyo, Marliyati, Taufik, and Jin-Cherng Shyu. "A Numerical Study of Bubble Blockage in Microfluidic Fuel Cells." Processes 10, no. 5 (May 6, 2022): 922. http://dx.doi.org/10.3390/pr10050922.

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Based on fuel crossover behavior and bubble nucleation in the microfluidic fuel cell’s channel, this research numerically presents the performance of air-breathing direct formic acid microfluidic fuel cells. In the simulation, a three-dimensional microfluidic fuel cell model was used. The continuity, momentum, species transport, and charge equations were used to develop the model transport behavior, whereas the Brinkman equation represented the porous medium flow in the gas diffusion layer. The I–V and power density curves are generated using the Butler–Volmer equation. The simulation and current experimental data were compared under identical operating conditions to validate the I–V curve of the microfluidic fuel cell model. The model was used to investigate the current density distribution in the microchannel due to bubble obstruction and the reactant concentration on both electrodes. Fuel crossover resulted in a large decrease in open-circuit voltage and a reduction in fuel concentration above the anode electrode. The findings also showed that a low-flow rate air-breathing direct formic acid microfluidic fuel cell is more prone to CO2 bubble formation.
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20

Liu, Chang, Guangqiang Li, Lifeng Zhang, Qiang Wang, and Qiang Wang. "A Three-Dimensional Comprehensive Numerical Model of Ion Transport during Electro-Refining Process for Scrap-Metal Recycling." Materials 15, no. 8 (April 11, 2022): 2789. http://dx.doi.org/10.3390/ma15082789.

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A transient three-dimensional comprehensive numerical model was established to study ion transport caused by diffusion, convection, and electro-migration in the electro-refining process for scrap-metal recycling. The Poisson–Nernst–Planck equations were used to define ion transport within the electrolyte, while the Naiver–Stokes equations and the energy equation were employed to describe fluid flow and heat transfer. In addition, the Butler-Volmer formulation was used to represent the kinetics of the electrochemical reaction. The comparison between the measured and simulated data indicates the reliability of the model. Under the action of diffusion and electro-migration, the positive copper ion moves from the anode to the cathode, while the negative sulfate ion migrates in the opposite direction. The distribution of the ion concentration, however, greatly changes if the fluid flow is taken into account. The ion concentration around the anode and the rate of the electrochemical reaction that occurs at the anode surface are reduced by the fluid flow. The proposed computational framework offers a valuable basis for future research and development in the field of scrap-metal recycling technology.
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21

Barbero, G., and A. M. Scarfone. "A kinetic derivation of a Butler-Volmer-like equation for the current-voltage characteristics in an adsorbing medium." Journal of Molecular Liquids 349 (March 2022): 118475. http://dx.doi.org/10.1016/j.molliq.2022.118475.

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22

Noren, D. A., and M. A. Hoffman. "Clarifying the Butler–Volmer equation and related approximations for calculating activation losses in solid oxide fuel cell models." Journal of Power Sources 152 (December 2005): 175–81. http://dx.doi.org/10.1016/j.jpowsour.2005.03.174.

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23

Li, Yueqi, Hui Wang, Zixiao Wang, Yanjun Qiao, Jens Ulstrup, Hong-Yuan Chen, Gang Zhou, and Nongjian Tao. "Transition from stochastic events to deterministic ensemble average in electron transfer reactions revealed by single-molecule conductance measurement." Proceedings of the National Academy of Sciences 116, no. 9 (February 8, 2019): 3407–12. http://dx.doi.org/10.1073/pnas.1814825116.

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Electron transfer reactions can now be followed at the single-molecule level, but the connection between the microscopic and macroscopic data remains to be understood. By monitoring the conductance of a single molecule, we show that the individual electron transfer reaction events are stochastic and manifested as large conductance fluctuations. The fluctuation probability follows first-order kinetics with potential dependent rate constants described by the Butler–Volmer relation. Ensemble averaging of many individual reaction events leads to a deterministic dependence of the conductance on the external electrochemical potential that follows the Nernst equation. This study discloses a systematic transition from stochastic kinetics of individual reaction events to deterministic thermodynamics of ensemble averages and provides insights into electron transfer processes of small systems, consisting of a single molecule or a small number of molecules.
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24

Cao, Jun, and Ned Djilali. "Numerical Modeling of PEM Fuel Cells Under Partially Hydrated Membrane Conditions." Journal of Energy Resources Technology 127, no. 1 (March 1, 2005): 26–36. http://dx.doi.org/10.1115/1.1825048.

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In proton-exchange membrane fuel cells it is particularly important to maintain appropriate water content and temperature in the electrolyte membrane. The water balance depends on the coupling between diffusion of water, pressure variation, and the electro-osmotic drag in the membrane. In this paper we apply conservation laws for water and current, in conjunction with an empirical relationship between electro-osmotic drag and water content, to obtain a transport equation for water molar concentration and to derive a new equation for the electric potential that strictly accounts for variable water content and is more accurate than the conventionally used Laplace’s equation. The model is coupled with a computational fluid dynamics model that includes the porous gas diffusion electrodes and the reactant flow channels. The resulting coupled model accounts for multi-species diffusion (Stefan-Maxwell equation); first-order reaction kinetics (Butler-Volmer equation); proton transport (Nernst-Planck equation); and water transport in the membrane (Schlo¨gl equation). Numerical simulations for a two-dimensional cell are performed over nominal current densities ranging from i=0.4 to i=1.2 A/cm2. The relationship between humidification and the membrane potential loss is investigated, and the impact and importance of two-dimensionality, temperature, and pressure nonuniformities are analyzed and discussed.
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25

Huang, K., Thangavel Sangeetha, Wu-Fu Cheng, Chunyo Lin, and Po-Tuan Chen. "Computational Fluid Dynamics Approach for Performance Prediction in a Zinc–Air Fuel Cell." Energies 11, no. 9 (August 21, 2018): 2185. http://dx.doi.org/10.3390/en11092185.

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In this study, we investigated the development of a computational fluid dynamics (CFD) model for simulating the physical and chemical processes in a zinc (Zn)–air fuel cell. Theoretically, the model was based on time-dependent, three-dimensional conservation equations of mass, momentum, and species concentration. The complex electrochemical reactions occurring within the porous electrodes were described by the Butler–Volmer equation with velocity, pressure, current density, and electronic and ionic phase potentials computed in electrodes. The Zn–air fuel cell for the present study comprised of four major components, such as a porous Zn anode electrode, air cathode electrode, liquid potassium hydroxide (KOH) electrolyte, and air flow channels. The numerical results were first compared with the experiments, showing close agreement with the predicted and experimental values of the measured voltage–current data of a single Zn–air fuel cell. Numerical results also exhibited mass fraction contours of oxygen (O2) and zinc oxide (ZnO) in the mid-cross-sectional plane. A parametric study was extended to assess the performance of a Zn–air fuel cell at various cathode and electrolyte parameters.
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26

Kuo, Ting-Jung. "Development of a Comprehensive Model for the Coulombic Efficiency and Capacity Fade of LiFePO4 Batteries under Different Aging Conditions." Applied Sciences 9, no. 21 (October 28, 2019): 4572. http://dx.doi.org/10.3390/app9214572.

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In this paper, a comprehensive model for LiFePO4 batteries is proposed to ensure high efficiency and safe operation. The proposed model has a direct correlation between its parameters and the electrochemical principles to estimate the state of charge (SoC) and the remaining capacity of the LiFePO4 battery. This model was based on a modified Thévenin circuit, Butler–Volmer kinetics, the Arrhenius equation, Peukert’s law, and a back propagation neural network (BPNN), which can be divided into two parts. The first part can be represented by the dual exponential terms, responsive to the Coulomb efficiency; the second part can be described by the BPNN, estimating the remaining capacity. The model successfully estimates the SoC of the batteries that were tested with an error of 1.55%. The results suggest that the model is able to accurately estimate the SoC and the remaining capacity in various environments (discharging C rates and temperatures).
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27

Dickinson, Edmund J. F., and Andrew J. Wain. "Corrigendum to “The Butler-Volmer equation in electrochemical theory: Origins, value, and practical application” [J. Electroanal. Chem. 872 (2020) 114145]." Journal of Electroanalytical Chemistry 901 (November 2021): 115774. http://dx.doi.org/10.1016/j.jelechem.2021.115774.

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28

Piłatowicz, Grzegorz, Heide Budde-Meiwes, Julia Kowal, Christel Sarfert, Eberhard Schoch, Martin Königsmann, and Dirk Uwe Sauer. "Determination of the lead-acid battery's dynamic response using Butler-Volmer equation for advanced battery management systems in automotive applications." Journal of Power Sources 331 (November 2016): 348–59. http://dx.doi.org/10.1016/j.jpowsour.2016.09.066.

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29

Momeni, M., and J. C. Wren. "A mechanistic model for oxide growth and dissolution during corrosion of Cr-containing alloys." Faraday Discussions 180 (2015): 113–35. http://dx.doi.org/10.1039/c4fd00244j.

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We have developed a corrosion model that can predict metal oxide growth and dissolution rates as a function of time for a range of solution conditions. Our model considers electrochemical reactions at the metal/oxide and oxide/solution interfaces, and the metal cation flux from the metal to the solution phase through a growing oxide layer, and formulates the key processes using classical chemical reaction rate or flux equations. The model imposes mass and charge balance and hence, is labeled as the Mass Charge Balance (MCB) model. Mass and charge balance dictate that at any given time the oxidation (or metal cation) flux must be equal to the sum of the oxide growth flux and the dissolution flux. For each redox reaction leading to the formation of a specific oxide, the metal oxidation flux is formulated using a modified Butler–Volmer equation with an oxide-thickness-dependent effective overpotential. The oxide growth and dissolution fluxes have a first-order dependence on the metal cation flux. The rate constant for oxide formation also follows an Arrhenius dependence on the potential drop across the oxide layer and hence decreases exponentially with oxide thickness. This model is able to predict the time-dependent potentiostatic corrosion behaviour of both pure iron, and Co–Cr and Fe–Ni–Cr alloys.
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30

LIEW CHALU, CHRISTOPHER JANTING. "Modelling and Simulation of A Direct Ethanol Fuel Cell: Electrochemical Reactions and Mass Transport Consideration." Journal of Applied Science & Process Engineering 9, no. 1 (April 30, 2022): 1128–38. http://dx.doi.org/10.33736/jaspe.4592.2022.

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Mathematical modelling was developed for direct ethanol fuel cell (DEFC) by considering electrochemical reactions and mass transport. The model was validated against experimental data from previous research and showed good agreement with the data. The developed mathematical modelling for this research was based on the Butler-Volmer equation, Tafel equation and Fick’s law. The model was used to investigate parameters such as ethanol concentration and cell operating temperature. The developed mathematical model simulated the data from previous research. Ethanol concentration played a vital role to achieve high-performance DEFC. The higher the ethanol concentration, the higher current could be generated in DEFC. Nonetheless, the higher the usage of the ethanol concentration, the higher the ethanol crossover might occur. The highest current density produced from the fuel cell was at 21.48 mA cm-2, for 2M of ethanol concentration. Operating temperature also affected cell performance. The higher the operating temperature, the higher power density could be generated—the peak power density of 5.7 mWcm-2 at 75 oC with 2M of ethanol. As for ethanol crossover, the highest ethanol crossover was at 12.4 mol m-3 for 3M concentration of ethanol. It proved that higher ethanol concentration led to higher ethanol crossover.
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31

Lyu, Jinzhe, Viktor Kudiiarov, and Andrey Lider. "Corrections of Voltage Loss in Hydrogen-Oxygen Fuel Cells." Batteries 6, no. 1 (February 6, 2020): 9. http://dx.doi.org/10.3390/batteries6010009.

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Normally, the Nernst voltage calculated from the concentration of the reaction gas in the flow channel is considered to be the ideal voltage (reversible voltage) of the hydrogen-oxygen fuel cell. The Nernst voltage loss in fuel cells in most of the current literature is thought to be due to the difference in concentration of reaction gas in the flow channel and concentration of reaction gas on the catalyst layer at the time as when the high net current density is generated. Based on the Butler–Volmer equation in the hydrogen-oxygen fuel cell, this paper demonstrates that Nernst voltage loss caused by concentration difference of reaction gas in the flow channel and reaction gas on the catalyst layer at equilibrium potential. According to the relationship between the current density and the concentration difference it can be proven that Nernst voltage loss does not exist in hydrogen-oxygen fuel cells because there is no concentration difference of reaction gas in the flow channel and on the catalytic layer at equilibrium potential when the net current density is zero.
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32

Prokop, Tomasz A., Katarzyna Berent, Marcin Mozdzierz, Janusz S. Szmyd, and Grzegorz Brus. "A Three-Dimensional Microstructure-Scale Simulation of a Solid Oxide Fuel Cell Anode—The Analysis of Stack Performance Enhancement After a Long-Term Operation." Energies 12, no. 24 (December 15, 2019): 4784. http://dx.doi.org/10.3390/en12244784.

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In this research, we investigate the connection between an observed enhancement in solid oxide fuel cell stack performance and the evolution of the microstructure of its electrodes. A three dimensional, numerical model is applied to predict the porous ceramic-metal electrode performance on the basis of microstructure morphology. The model features a non-continuous computational domain based on the digital reconstruction obtained using focused ion beam scanning electron microscopy (FIB-SEM) electron nanotomography. The Butler–Volmer equation is used to compute the charge transfer at reaction sites, which are modeled as distinct locally distributed features of the microstructure. Specific material properties are accounted for using interpolated experimental data from the open literature. Mass transport is modeled using the extended Stefan–Maxwell model, which accounts for both the binary, and the Knudsen diffusion phenomena. The simulations are in good agreement with the experimental data, correctly predicting a decrease in total losses for the observed microstructure evolution. The research supports the hypothesis that the performance enhancement was caused by a systematic change in microstructure morphology.
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33

Engelken, R. D., and T. P. Van Doren. "Ionic Electrodeposition of II–VI and III–V Compounds: I . Development of a Simple, Butler‐Volmer Equation‐Based Kinetic Model for Electrodeposition." Journal of The Electrochemical Society 132, no. 12 (December 1, 1985): 2904–9. http://dx.doi.org/10.1149/1.2113692.

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34

Jiang, Jiuchun, Sijia Liu, Zeyu Ma, Le Yi Wang, and Ke Wu. "Butler-Volmer equation-based model and its implementation on state of power prediction of high-power lithium titanate batteries considering temperature effects." Energy 117 (December 2016): 58–72. http://dx.doi.org/10.1016/j.energy.2016.10.087.

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35

Cannarozzo, Marco, Simone Grosso, Gerry Agnew, Adriana Del Borghi, and Paola Costamagna. "Effects of Mass Transport on the Performance of Solid Oxide Fuel Cells Composite Electrodes." Journal of Fuel Cell Science and Technology 4, no. 1 (April 3, 2006): 99–106. http://dx.doi.org/10.1115/1.2393311.

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Composite electrodes are of great interest in the field of solid oxide fuel cells because their use can improve the performance of these cells. However, an important correlation exists between composition, microstructure, and thickness of an electrode and its performance. This correlation has been investigated in this work using a theoretical model. The model, in order to consider all the losses occurring in an electrode, includes Ohm’s law for ionic and electronic charge transport, and the Butler-Volmer equation to evaluate the activation polarizations, and mass transport equations, taking into account diffusion through porous media, to evaluate the concentration losses. The model shows that the best electrode performance is a trade-off between activation and concentration losses. This is because a decrease in the dimensions of the particles or an increase in its thickness result, on the one hand, in a reduction of the activation polarizations, because of a larger active area for the electrochemical reaction, and, on the other hand, in an increase in the concentration losses due to a more difficult gas diffusion. In particular, in order to understand the impact of concentration losses on the performance of composite electrodes, the simulations have been run with two models, one including and the other one neglecting the mass transport equations. The results show that concentration losses play a role only with thick electrodes composed of small particles, operating at high fuel utilization.
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36

Zhang, Meng, Bo Liang, Junhan Luo, Mingjian He, Weibing Wang, Yang Yang, Yu Zhou, Liman Chen, and Caishan Jiao. "A Finite-Element Model for Underpotential Deposition of Ce(III) on an Active Aluminum Electrode in LiCl–KCl Melts." Journal of The Electrochemical Society 169, no. 4 (April 1, 2022): 042506. http://dx.doi.org/10.1149/1945-7111/ac6221.

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Underpotential deposition on an active Al cathode plays an increasingly important role in pyroprocessing of used nuclear fuel, but most of the developed models are applied to simulate underpotential deposition at atomic level without considering electron transfer process which is a critical step in electrochemical reactions. In this work, a novel finite-element model for the underpotential deposition of Ce(III) in LiCl–KCl melts is developed with the consideration of Ce(III) activity in the Al electrode and the electron transfer process which is described by Butler-Volmer equation. This model was applied to investigate cyclic voltammetry(CV), square wave voltammetry(SWV) and electrodeposition behaviors of Ce(III) on an Al/Mo electrode. Additionally, the effect of temperature and electrode surface area on the electrodeposition thickness was investigated. Simulated CV and SWV curves are obtained and compared with our pervious experimental data. The results also provide the distribution diagrams of current density, electrostatic potential, Ce(III) concentration and electrodeposition thickness. Furthermore, the electrodeposition thickness is found to be linearly proportional to temperature and the inverse of cathode’s area, respectively. This work proposes a new pathway for the further study of underpotential deposition process.
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37

Wu, Chunping, Yiran Zhang, Bang Xiao, Lin Yang, Anqi Jiao, Yinan Wang, Xuteng Zhao, and He Lin. "YSZ-Based Mixed Potential Type Sensors Utilizing Pd-doped SrFeO3 Perovskite Sensing Electrode to Monitor Sulfur Dioxide Emission." Journal of The Electrochemical Society 169, no. 3 (March 1, 2022): 037508. http://dx.doi.org/10.1149/1945-7111/ac593c.

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Sulfur dioxide (SO2) is one of the key pollutants in the atmosphere that should be monitored in many combustion facilities. In this paper, YSZ-based mixed potential SO2 sensors were developed utilizing the perovskite-type SrFeO3 sensing electrode, and Pd doping was applied to enhance the sensing performance. It was found that the sensor utilizing the Pd0.05-SrFeO3 sensing electrode showed the highest sensitivity toward 1–30 ppm SO2 at 575 ° C , and exhibited a piecewise linear relationship between Δ V and the logarithm of SO2 concentrations in this concentration range. The significant enhancement of sensing performances by 5 at% Pd doping was mainly attributed to the increasing of electrochemical catalytic activity of the anodic reaction. After the sensing performance test in the temperature range between 525 ° C –625 ° C , 575 ° C was selected as the optimum operating temperature. The sensing performances of the developed Pd0.05-SrFeO3 sensor were further evaluated at 575 ° C , exhibiting good selectivity to CO, CO2, NO, and NO2 interference and good long-term stability. In addition, the fluctuation of oxygen concentration can be corrected by the Butler-Volmer equation following the mixed potential theory.
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38

Li, Xiaoyu, Wen Hua, Jindong Tian, and Yong Tian. "A Multi-Particle Physics-Based Model of a Lithium-Ion Battery for Fast-Charging Control Application." World Electric Vehicle Journal 12, no. 4 (October 17, 2021): 196. http://dx.doi.org/10.3390/wevj12040196.

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The charging safety of electric vehicles is an area of focus in the electric automobile industry. For the purpose of ensuring safety, charging electric vehicles as soon as possible is a goal pursued by the public. In order to ensure the safety of electric vehicles during fast charging and to reduce the cycle life decay of the battery, a simplified multi-particle lithium-ion battery model is proposed, based on the pseudo two-dimensional (P2D) model. The model was developed by considering heterogeneous electrochemical reactions in the negative electrode area. The Butler–Volmer (BV) kinetic equation and the distribution of the pore wall flux in the negative electrode is approximated by the quasi-linear approximation method. Furthermore, this paper also analyzes the conditions of lithium precipitation from the negative electrode of a lithium-ion battery in the case of high charging rates, which has a certain reference significance for fast-charging control applications. The experimental and simulation results show that the model has a high simulation accuracy and can reflect the heterogeneity of electrochemical reactions in the negative electrode of the battery. The model can be adapted to fast-charging control applications.
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39

Ghanbari, Elmira, Alireza Saatchi, Xiaowei Lei, and Digby D. Macdonald. "Studies on Pitting Corrosion of Al–Cu–Li Alloys Part III: Passivation Kinetics of AA2098–T851 Based on the Point Defect Model." Materials 12, no. 12 (June 13, 2019): 1912. http://dx.doi.org/10.3390/ma12121912.

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In this paper, the passivation kinetics of AA2098–T851 was investigated by a fundamental theoretical interpretation of experimental results based on the mixed potential model (MPM). The steady state passive layer formed on the AA2098–T851 in NaHCO3 solution in a CO2 atmosphere upon potentiostatic stepping in the anodic direction followed by stepping in the opposite direction was explored. Potentials were selected in a way that both anodic passive dissolution of the metal and hydrogen evolution reaction (HER) occur, thereby requiring the MPM for interpretation. Optimization of the MPM on the experimental electrochemical impedance spectroscopy (EIS) data measured after each potentiostatic step revealed the important role of the migration of Al interstitials in determining the kinetics of passive layer formation and dissolution. More importantly, it is shown that the inequalities of the kinetics of formation and dissolution of the passive layer as observed in opposite potential stepping directions lead to the irreversibility of the passivation process. Finally, by considering the Butler–Volmer (B–V) equation for the cathodic reaction (HER) in the MPM, and assuming the quantum mechanical tunneling of the charge carriers across the barrier layer of the passive film, it was shown that the HER was primarily controlled by the slow electrochemical discharge of protons at the barrier layer/solution (outer layer) interface.
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40

Bark, Fritz H., and Farid Alavyoon. "Free convection in an electrochemical system with nonlinear reaction kinetics." Journal of Fluid Mechanics 290 (May 10, 1995): 1–28. http://dx.doi.org/10.1017/s0022112095002394.

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Unsteady electrolysis of a dilute solution of a metal salt made up of two ions in a system with vertical electrodes is considered for large values of the Rayleigh and Schmidt numbers. The mass transfer at the electrodes is assumed to be related to the local charge transfer potential and concentration by a nonlinear Butler–Volmer law. Free convection of the electrolyte appears owing to the variation of the concentration field. After a short initial period, the electrolyte becomes strongly stratified and the motion takes place in boundary layers at the solid boundaries. An approximate model equation for the evolution of the stratification is derived by using perturbation theory. Predictions from the simplified model are found to be in good agreement with numerical solutions of the complete problem. Significant differences compared with earlier studies for linear kinetics, i.e. cases in which the electric current density at the electrodes is constant, are found. Among other things, for large values of the difference ΔV in electric potential between the electrodes, most of the dissolved salt eventually collects near the bottom of the cell. The concentration in the bulk of the electrolyte is, for large values of ΔV, approximately given by a ninth-order polynomial to be compared with a linear behaviour for linear kinetics.
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41

Gao, Yu, Yuwen Liu, and Shengli Chen. "A theoretical consideration of ion size effects on the electric double layer and voltammetry of nanometer-sized disk electrodes." Faraday Discussions 193 (2016): 251–63. http://dx.doi.org/10.1039/c6fd00087h.

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Considering that an electric-double-layer (EDL) structure may significantly impact on the mass transport and charge transfer kinetics at the interfaces of nanometer-sized electrodes, while EDL structures could be altered by the finite sizes of electrolyte and redox ions, the possible effects of ion sizes on EDL structures and voltammetric responses of nanometer-sized disk (nanodisk) electrodes are investigated. Modified Boltzmann and Nernst–Planck (NP) equations, which include the influence of the finite ion volumes, are combined with the Poisson equation and modified Butler–Volmer equation to gain knowledge on how the finite sizes of ions and the nanometer sizes of electrodes may couple with each other to affect the structures and reactivities of a nanoscale electrochemical interface. Two typical ion radii, 0.38 nm and 0.68 nm, which could represent the sizes of the commonly used aqueous electrolyte ions (e.g., the solvated K+) and the organic electrolyte ions (e.g., the solvated TEA+) respectively, are considered. The finite size of ions can result in decreased screening of electrode charges, therefore magnifying EDL effects on the ion transport and the electron transfer at electrochemical interfaces. This finite size effect of ions becomes more pronounced for larger ions and at smaller electrodes as the electrode radii is larger than 10 nm. For electrodes with radii smaller than 10 nm, however, the ion size effect may be less pronounced with decreasing the electrode size. This can be explained in terms of the increased edge effect of disk electrodes at nanometer scales, which could relax the ion crowding at/near the outer Helmholtz plane. The conditions and situations under which the ion sizes may have a significant effect on the voltammetry of electrodes are discussed.
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42

Rathod, Nikita, Peter Slater, George Sergi, Gamini Seveviratne, and David Simpson. "A fresh look at depolarisation criteria for cathodic protection of steel reinforcement in concrete." MATEC Web of Conferences 289 (2019): 03011. http://dx.doi.org/10.1051/matecconf/201928903011.

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Criteria for the successful application of cathodic protection (CP) for steel reinforced concrete have been fixed for decades and form part of ISO EN12696. The most used criterion is the achievement of 100 mV depolarization over a period not exceeding 24 hours after discontinuation of the applied current. Although more empirical than theoretically based, the criterion has served the CP industry well. It does, however, exclude any systems that may not always achieve that level of depolarization but have been shown to offer adequate protection, and so there is a need to explore ways of assessing depolarisation data more effectively. On a fundamental level, non-linear polarisation, as described by the Butler Volmer equation, relates corrosion rate to polarisation for a given applied current density and shows that at low current densities, estimated corrosion rates can be shown to be still insignificant at less than 100 mV polarisations. This paper explores the use of non-linear polarisation as an additional supportive criterion based on the measured 24-hour depolarisation level for a known applied current density and tests its applicability in the laboratory and in the field. It speculates that a reducing apparent corrosion current density trend in combination with a depolarised potential moving in a more noble direction is likely to be a suitable alternative criterion, where 100 mV depolarisation is not achieved.
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43

Anderson, Grace C., Douglas Kushner, Alexis T. Bell, and Adam Z. Weber. "Impact of Proton Activity in PFSA Membranes on Electrochemical Kinetics Using Microelectrodes." ECS Meeting Abstracts MA2022-02, no. 42 (October 9, 2022): 1537. http://dx.doi.org/10.1149/ma2022-02421537mtgabs.

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Polymer-electrolyte fuel cells and electrolyzers (PEFC&Es) have the potential to play a prominent role in green energy technologies including transportation, chemical manufacturing, and grid-scale energy storage. PEFC&Es have made significant advancements in recent years, largely due to improvements in the catalyst layers, and especially at the ionomer/catalyst interface. However, it is not yet definitively known how this solid-state environment impacts electrochemical kinetics, especially under various operating conditions (e.g., temperature, humidity, etc.). Additionally, it is challenging to probe local conditions at the catalyst/ionomer interface using traditional analytical techniques. In this study, we explore the influence and nature of proton activity in Nafion and 3M ionomers using a specialized microelectrode setup containing a 50 μm platinum microelectrode in a solid-state three-electrode cell for hydrogen oxidation and evolution (HOR&HER) reactions. Proton activity was calculated through open circuit voltage measurements, and was found to increase with increasing water content, mirroring trends in reaction performance. The effect of proton activity on the reactions' kinetics was investigated using semi-empirical fitting with the Butler-Volmer equation, which gives insight into the reaction rate order and possible mechanism for the reactions. This study demonstrates that microelectrodes can be used to probe solid-state kinetics and can also elucidate complex ion interactions within the ionomer at the catalyst/ionomer interface.
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44

Yang, Zicheng, Saida Cora, Vincent Briselli, and Niya Sa. "Finite-Element Simulation for Ion Co-Intercalation Chemistry on Si Anode at Lithium-Ion Half-Cell." ECS Meeting Abstracts MA2022-02, no. 4 (October 9, 2022): 495. http://dx.doi.org/10.1149/ma2022-024495mtgabs.

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The increasing demand for higher capacity energy storage technologies is rapidly becoming an important consideration in the development of EV and related energy storage devices. Silicon is one promising solution as an earth-abundant element with a higher capacity than the more commonly used graphite anode of a lithium-ion battery. However, silicon anodes face unique challenges with volume expansion, notable during lithium ion intercalation and the stability of the SEI layer. To solve this problem, some recent research efforts discovered introducing a co-intercalation ion in the traditional lithium electrolyte Gen2 increases the coulombic efficiency, capacity, and stability of the silicon anode, but its mechanism of action remains unclear. In this work, in combination with experimental measurements we demonstrate the use of Newman's P2D Lithium Model in COMSOL together with the Butler-Volmer equation and concentrated solution theory to describe cation co-intercalation into the porous silicon anode material. Experimental data indicates that phase formation and transformation coincide with ion insertion, as reflected in the current response signal. Both the original ion intercalation and the foreign ion intercalation are reflected by CV generated by our model under the influence of model parameters, such as the variable speed of potential changed per second. As designed, our model can be extended towards general application in the cointercalation system and understanding of the foreign ion effect.
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45

Lin, Hongjian, Sarah Wu, and Jun Zhu. "Modeling Power Generation and Energy Efficiencies in Air-Cathode Microbial Fuel Cells Based on Freter Equations." Applied Sciences 8, no. 10 (October 19, 2018): 1983. http://dx.doi.org/10.3390/app8101983.

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The model proposed in this study was based on the assumption that the biomass attached to the anode served as biocatalysts for microbial fuel cell (MFC) exoelectrogenesis, and this catalytic effect was quantified by the exchange current density of anode. By modifying the Freter model and combining it with the Butler–Volmer equation, this model could adequately describe the processes of electricity generation, substrate utilization, and the suspended and attached biomass concentrations, at both batch and continuous operating modes. MFC performance is affected by the operating variables such as initial substrate concentration, external resistor, influent substrate concentration, and dilution rate, and these variables were revealed to have complex interactions by data simulation. The external power generation and energy efficiency were considered as indices for MFC performance. The simulated results explained that an intermediate initial substrate concentration (about 100 mg/L under this reactor configuration) needed to be chosen to achieve maximum overall energy efficiency from substrate in the batch mode. An external resistor with the value approximately that of the internal resistance, boosted the power generation, and a resistor with several times of that of the internal resistance achieved better overall energy efficiency. At continuous mode, dilution rate significantly impacted the steady-state substrate concentration level (thus substrate removal efficiency and rate), and attached biomass could be fully developed when the influent substrate concentration was equal to or higher than 100 mg/L at any dilution rate of the tested range. Overall, this relatively simple model provided a convenient way for evaluating and optimizing the performance of MFC reactors by regulating operating parameters.
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46

Takagishi, Yoichi, Takumi Yamanaka, and Tatsuya Yamaue. "Machine Learning Approaches for Designing Mesoscale Structure of Li-Ion Battery Electrodes." Batteries 5, no. 3 (August 1, 2019): 54. http://dx.doi.org/10.3390/batteries5030054.

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We have proposed a data-driven approach for designing the mesoscale porous structures of Li-ion battery electrodes, using three-dimensional virtual structures and machine learning techniques. Over 2000 artificial 3D structures, assuming a positive electrode composed of randomly packed spheres as the active material particles, are generated, and the charge/discharge specific resistance has been evaluated using a simplified physico-chemical model. The specific resistance from Li diffusion in the active material particles (diffusion resistance), the transfer specific resistance of Li+ in the electrolyte (electrolyte resistance), and the reaction resistance on the interface between the active material and electrolyte are simulated, based on the mass balance of Li, Ohm’s law, and the linearized Butler–Volmer equation, respectively. Using these simulation results, regression models, using an artificial neural network (ANN), have been created in order to predict the charge/discharge specific resistance from porous structure features. In this study, porosity, active material particle size and volume fraction, pressure in the compaction process, electrolyte conductivity, and binder/additives volume fraction are adopted, as features associated with controllable process parameters for manufacturing the battery electrode. As a result, the predicted electrode specific resistance by the ANN regression model is in good agreement with the simulated values. Furthermore, sensitivity analyses and an optimization of the process parameters have been carried out. Although the proposed approach is based only on the simulation results, it could serve as a reference for the determination of process parameters in battery electrode manufacturing.
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47

Leddy, Johna, and Joshua Richard Coduto. "(Invited, Digital Presentation) Tafel Analysis Algorithm: Objective Identification of the Linear Region." ECS Meeting Abstracts MA2022-01, no. 45 (July 7, 2022): 1879. http://dx.doi.org/10.1149/ma2022-01451879mtgabs.

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Electrocatalysts for hydrogen evolution and oxidation (HER and HOR) reactions, oxygen reduction and evolution (ORR and OER) reactions, and carbon dioxide reduction reactions (CO2RR) are evaluated by Tafel analysis. The Tafel equation specifies the log-linear relationship between current and overpotential 𝛈. Heterogenous electron transfer parameters of exchange current density j o and transfer coefficient 𝛂 are found. Standard heterogenous electron transfer rate k 0 can be found from j o. Conventionally, Tafel analysis is an extension of the Butler-Volmer equation applied at high overpotentials but where mass transport is not significant and the reverse reaction rate is negligible. Applicable at high 𝛈 when electron transfer rates are slow, kinetic parameters are extracted by linear regression. The conventional method is, however, subject to inaccuracies because the linear region is often determined subjectively, without attention to the constraints on overpotential range, no mass transport limitations, and low j o. An algorithm is developed to automate Tafel analysis with the objective to increase measurement accuracy and decrease subjective identification of the linear region. From linear sweep voltammograms (LSVs), j o and α are determined from Tafel slopes in the best fit, linear range. Comparisons of kinetic parameters between conventional and algorithmic Tafel analyses are made for the hydrogen evolution reaction (HER, 2H+ + 2e- ⇌ H2) on various unmodified electrodes and electrodes modified with Nafion® composites. The algorithmic Tafel analysis parameters correlate well with conventional Tafel analyses that respect constraints on mass transport, 𝛈, and j o. Similar agreement is observed between literature and algorithmically fitted kinetic parameters for different electrochemical systems. The algorithm allows for straightforward, rapid Tafel analysis for improved measurement of rate parameters that is independent of user bias in selection of the linear region. Acknowledgments This work was supported by the Army Research Office.
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48

Hirbodvash, Zohreh, Mohamed S. E. Houache, Oleksiy Krupin, Maryam Khodami, Howard Northfield, Anthony Olivieri, Elena A. Baranova, and Pierre Berini. "Electrochemical Performance of Lithographically-Defined Micro-Electrodes for Integration and Device Applications." Chemosensors 9, no. 10 (September 28, 2021): 277. http://dx.doi.org/10.3390/chemosensors9100277.

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Small; lithographically-defined and closely-spaced metallic features of dimensions and separation in the micrometer range are of strong interest as working and counter electrodes in compact electrochemical sensing devices. Such micro-electrode systems can be integrated with microfluidics and optical biosensors, such as surface plasmon waveguide biosensors, to enable multi-modal sensing strategies. We investigate lithographically-defined gold and platinum micro-electrodes experimentally, via cyclic voltammetry (CV) measurements obtained at various scan rates and concentrations of potassium ferricyanide as the redox species, in potassium nitrate as the supporting electrolyte. The magnitude of the double-layer capacitance is estimated using the voltammograms. Concentration curves for potassium ferricyanide are extracted from our CV measurements as a function of scan rate, and could be used as calibration curves from which an unknown concentration of potassium ferricyanide in the range of 0.5–5 mM can be determined. A blind test was done to confirm the validity of the calibration curve. The diffusion coefficient of potassium ferricyanide is also extracted from our CV measurements by fitting to the Randles–Sevcik equation (D = 4.18 × 10−10 m2/s). Our CV measurements were compared with measurements obtained using macroscopic commercial electrodes, yielding good agreement and verifying that the shape of our CV curves do not depend on micro-electrode geometry (only on area). We also compare our CV measurements with theoretical curves computed using the Butler–Volmer equation, achieving essentially perfect agreement while extracting the rate constant at zero potential for our redox species (ko = 10−6 m/s). Finally, we demonstrate the importance of burn-in to stabilize electrodes from the effects of electromigration and grain reorganization before use in CV measurements, by comparing with results obtained with as-deposited electrodes. Burn-in (or equivalently, annealing) of lithographic microelectrodes before use is of general importance to electrochemical sensing devices
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49

Rodrigues, Romain, Stéphane Gaboreau, Julien Gance, Ioannis Ignatiadis, and Stéphanie Betelu. "Indirect Galvanostatic Pulse in Wenner Configuration: Numerical Insights into Its Physical Aspect and Its Ability to Locate Highly Corroding Areas in Macrocell Corrosion of Steel in Concrete." Corrosion and Materials Degradation 1, no. 3 (December 21, 2020): 373–407. http://dx.doi.org/10.3390/cmd1030018.

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The use of indirect electrical techniques is gaining interest for monitoring the corrosion of steel in concrete as they do not require any connection to the rebar. In this paper, we provide insights into the physical aspects of the indirect galvanostatic pulse (GP) method in the Wenner configuration. Considering uniform corrosion, the instantaneous ohmic drop is decreased due to the presence of the rebar, which acts as a short-circuit. However, we observed that this phenomenon is independent of the electrochemical parameters of the Butler–Volmer equation. They are, however, responsible for the nonlinear decrease of the current that polarizes the rebar over time, especially for a passive rebar due to its high polarization resistance. This evolution of the resulting potential difference with time is explained by the increase of the potential difference related to concrete resistance and the global decrease of the potential difference related to the polarization resistance of the rebar. The indirect GP technique is then fundamentally different than the conventional one in three-electrode configuration, as here the steady-state potential is not only representative of polarization resistance but also of concrete resistance. Considering non-uniform corrosion, the presence of a small anodic area disturbs the current distribution in the material. This is essentially due to the different capability of anodic and cathodic areas to consume the impressed current, resulting in slowing down the evolution of the transient potential as compared to uniform corrosion. Hence, highly corroding areas have a greater effect on the transient potential than on the steady-state one. The use of this temporal evolution is thus recommended to qualitatively detect anodic areas. For the estimation of their length and position, which is one of the main current problematic issue when performing any measurement on reinforced concrete (RC) structures with conventional techniques, we suggest adjusting the probe spacing to modulate the sensitivity of the technique.
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50

Valentín Reyes, Jonathan, Maria Isabel Isabel Leon Sotelo, José L. Nava, Tzayam Perez, and Tatiana Romero. "Comparison of Serpentine and Interdigitated Monopolar Plates on the Performance of an Anion Exchange Membrane Fuel Cell By CFD." ECS Meeting Abstracts MA2022-02, no. 39 (October 9, 2022): 1405. http://dx.doi.org/10.1149/ma2022-02391405mtgabs.

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The continuous energy demand and the growing population have focussed the scientific research on developing alternative energy sources or green fuels. The anion exchange membrane fuel cell (AEMFC) arises as an excellent alternative because of its low-cost electrocatalyst used at the cathode, energy production, and no pollutants emissions to the environment. Nowadays, several studies have been conducted to improve the performance of the AEMFC modifying membrane materials, types of gas diffusion layers (GDL), and catalysts, among other cell components. However, the design of the flow channels by changing plate topologies and materials is still under development. About flow channels topologies, conventional geometries array (pin, straight, parallel, and serpentine) flow fields lead the flow in the direction parallel to the electrode surface, and the reactive gas flow towards the catalyst layer (CL) mainly by molecular diffusion. On the other hand, interdigitated flow fields provide convection velocity normal to the CL and forced convection flow in GDL for better mass transfer. The interdigitated flow fields could prevent water flooding and improve high current density operations performance. These flow fields have been tested in proton exchange membrane fuel cells (PEMFC) with excellent results at low current densities. Nonetheless, there is an essential balance and management of water in an AEMFC. It presents simultaneous production and consumption of water in anode and cathode, respectively, where the production is twice the consumption. Poor water management could provoke anode flooding or membrane drying. These scenarios are undesirable due to mass transport limitations, membrane polymer degradation, and cathodic channels flow can be flooded. Therefore, an appropriate design of flow field that allows the correct water balance on AEMFC is needed for optimal performance. This research deals with the computational fluid dynamic (CFD) comparison of serpentine and interdigitated flow fields on the performance of an AEMFC. For the development of this model, the Navier-Stokes and Brinkmann equations were implemented for momentum transfer. In addition, the average mixture model represents the transport of chemical species, and the Butler-Volmer equation denotes the electrochemical reaction at the CL; water balance is analyzed at low and high current densities to evaluate the scenarios above mention. Preliminary results indicate that a serpentine design is functional at the anode due to the water management is favored. An interdigitated flow field is implemented at the cathode to improve the distribution of the reactants from channels until the CL.
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