How to Model Ion-Exchange Membranes and Donnan Potentials

Henrik Ekström August 29, 2018

Ion-exchange membranes are widely employed within the field of electrochemical engineering. In polymer electrolyte fuel cells and vanadium flow batteries, they are used to conduct ions and at the same time prevent reactants and electrons from crossing between the two flow compartments. The ability to promote the passage of ions of either positive or negative charge is also used in electrodialysis for cleaning water from ions. In this blog post, we will explore the ion-selective capabilities of ion-exchange membranes.

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Thomas Forrister July 3, 2018

In electrochemistry, it’s common to use a microdisk as the working electrode in an analytical technique known as cyclic voltammetry. However, unlike with a macroelectrode, diffusion at a microelectrode occurs very fast on the timescale of the experiment. To simplify the analysis, we can use an approximation that assumes the microdisk has stationary diffusion properties on the timescale of the voltammetry study — eliminating the need for a time-dependent model.

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Brianne Costa June 14, 2018

After World War II, a boom in the economy caused Americans to buy a record number of cars (leading to serious levels of pollution). Today, we have more energy-efficient vehicles — such as hybrid and electric options — and another “boom” is occurring, this time for autonomous vehicles (AVs). Again, pollution is an issue, but in a different way: There’s a debate over whether self-driving cars should have hybrid engines to maximize profit or all-electric engines to minimize pollution.

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Edmund Dickinson September 5, 2017

Precision machining and quality of surface finish are major concerns for manufacturers of metal parts. The promise of a contactless method to machine surfaces with submillimeter precision and a clean surface, on metals of almost any hardness, might seem too good to be true. However, such a method, pulsed electrochemical machining (PECM), was the focus of a detailed investigation using numerical modeling presented at the COMSOL Conference 2016 Munich.

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Caty Fairclough August 15, 2017

Zone electrophoresis separates different species in a sample into distinct well-resolved peaks, giving scientists the ability to analyze substances like proteins and nucleic acids. Improving this electrophoretic separation technique requires us to accurately model the transport and separation of these species. Here, let’s look at how the COMSOL Multiphysics® software can be used to simulate the movement of species during zone electrophoresis.

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Bridget Cunningham March 10, 2017

While reverse electrodialysis (RED) is a promising source of renewable energy, it can be a challenging process to analyze. The performance of RED units is affected by the physical phenomena that occur when converting salinity gradient energy into electric current. To address this, one team of researchers used a novel approach to model such systems in the COMSOL Multiphysics® software. Their multiphysics model and subsequent simulation studies provide further insight into designing and optimizing RED units.

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Edmund Dickinson February 9, 2017

Electrochemical impedance spectroscopy is a versatile experimental technique that provides information about an electrochemical cell’s different physical and chemical phenomena. By modeling the physical processes involved, we can constructively interpret the experiment’s results and assess the magnitudes of the physical quantities controlling the cell. We can then turn this model into an app, making electrochemical modeling accessible to more researchers and engineers. Here, we will look at three different ways of analyzing EIS: experiment, model, and simulation app.

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Bridget Cunningham December 7, 2016

Traditional lithium-ion batteries use an electrolyte based on a flammable liquid solvent, which can cause them to catch fire if they overheat. In recent years, nonflammable solid electrolytes have been investigated as an alternative to improve battery design and safety. Optimizing this technology for industrial applications, however, requires a better understanding of the electrochemical processes inside the device. Simulation serves as a valuable tool for this purpose, helping to realize the use of solid-state lithium-ion batteries in the near future.

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Scott Smith August 24, 2016

Resistive and capacitive effects are fundamental to the understanding of electrochemical systems. The resistances and capacitances due to mass transfer can be represented through physical equations describing the corresponding fundamental phenomena, like diffusion. Further, when considering the resistive or capacitive behavior of double layers, thin films, and reaction kinetics, such effects can be treated simply through physical conditions relating electrochemical currents and voltages. Lastly, resistances and capacitances from external loading circuits can easily be represented in the COMSOL Multiphysics® software.

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Guest Matteo Lualdi August 23, 2016

Today, guest blogger Matteo Lualdi of resolvent ApS, a COMSOL Certified Consultant, discusses the benefits of creating a simulation app to analyze a solid oxide fuel cell stack. For many businesses, numerical modeling and simulation are valuable tools at various stages of the design workflow, from product development to optimization. Apps further extend the reach of these tools, hiding complex multiphysics models beneath easy-to-use interfaces. Here’s a look at one such example: a solid oxide fuel cell stack app.

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Bertil Nistad February 17, 2016

In version 5.2 of COMSOL Multiphysics, we offer a new feature for simulating corrosion in slender structures. This significantly speeds up the total time spent when working with structures such as oil platforms. By using the boundary element method (BEM) and specialized beam elements in the Current Distribution on Edges, BEM interface, there is no longer a need for a finite element mesh to resolve the whole 3D structure, saving time for large corrosion problems consisting of slender components.

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