Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Concentration of an ion at a set distance from an electrode surface

Please login with a confirmed email address before reporting spam

Hi,

I've been playing with comsol for a couple of months now to try and supplement some of my experimental work.

I'm trying to model the concentration profile of a positive ionic species as a function of distance from an electrode that has a negative potential. Drawing the domains is easy enough, and i can define the boundary potential at the electrode surface. But, how do i fill my sub domain with an ionic species and specify the charges on the ions etc?

As you can probably tell, I’m a beginner with comsol so any help would be greatly appreciated.

Thanks,

Rob

1 Reply Last Post Jun 30, 2009, 3:50 a.m. EDT

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jun 30, 2009, 3:50 a.m. EDT

Hi,

I've been playing with comsol for a couple of months now to try and supplement some of my experimental work.

I'm trying to model the concentration profile of a positive ionic species as a function of distance from an electrode that has a negative potential. Drawing the domains is easy enough, and i can define the boundary potential at the electrode surface. But, how do i fill my sub domain with an ionic species and specify the charges on the ions etc?

As you can probably tell, I’m a beginner with comsol so any help would be greatly appreciated.

Thanks,

Rob

A good method is to solve the governing equations for ion transport (Nernst-Planck) with realistic boundary conditions representing electrode reaction kinetics (Butler-Volmer). There are several examples available, for example the model library example Chemical_Engineering_Module/Electrochemical_Engineering/copper_deposition. A good reference paper on the method is this:

Asymptotic Analysis of Diffuse-Layer Effects on Time-Dependent Interfacial Kinetics,
Antoine Bonnefont et al.
dx.doi.org/10.1016/S0022-0728(00)00470-8

Niklas
[QUOTE] Hi, I've been playing with comsol for a couple of months now to try and supplement some of my experimental work. I'm trying to model the concentration profile of a positive ionic species as a function of distance from an electrode that has a negative potential. Drawing the domains is easy enough, and i can define the boundary potential at the electrode surface. But, how do i fill my sub domain with an ionic species and specify the charges on the ions etc? As you can probably tell, I’m a beginner with comsol so any help would be greatly appreciated. Thanks, Rob [/QUOTE] A good method is to solve the governing equations for ion transport (Nernst-Planck) with realistic boundary conditions representing electrode reaction kinetics (Butler-Volmer). There are several examples available, for example the model library example Chemical_Engineering_Module/Electrochemical_Engineering/copper_deposition. A good reference paper on the method is this: [i]Asymptotic Analysis of Diffuse-Layer Effects on Time-Dependent Interfacial Kinetics[/i], Antoine Bonnefont et al. http://dx.doi.org/10.1016/S0022-0728(00)00470-8 Niklas

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.