Hallo,(adsbygoogle = window.adsbygoogle || []).push({});

i'm trying to implement a comsol simulation of a impedance spectroscopy experiment.

But unfortunatly i'm an absolut beginner in Comsol and i have many problems with this work.

First of all i want to say that i'm using the AC/DC module, more precisely the transient analysis.

At the moment I'm using a simple 2D geometry to try out all equations and boundary conditions.

Now to the first problem:

I tried to simulate only a double layer capacitance between an electrode and a drop of water. The double layer thickness is very small compared to the dimensions of the electrodes, so I didn't want to draw it, but use a distributed impedance for the boundary condition between the electrode and the drop of water.

The other boundary conditions are:

Potential V= sin(10*t) on the left side of the electrode.

Potential V= -sin(10*t) on the right side of the drop of water.

All other boundaries are electrical insulated.

But it wasn't sucessfuly, I always recieve the whole potencial difference over the drop of water and not over the distributed impedance.

The second problem is that I have no idea how to bring the warburg impedance equation into the boundary conditions.

The equation is something like Z= sigma/sqrt(w)*(1-j), but where do I place that and how can i express w?

Finaly remains the question, if it is possible to make the simulations automatic over a defined range of frequencies and to calculate a complex impedance out of the result.

Attachments:

Comsol1: result, up a simulation with a drawed double layer, down the distributed impedance.

Comsol2: the boundary condition for the distributed impedance

Comsol3: the boundary condition of the electrode

thanke you for your help

and sorry for my bad english

cu FirePhoenix

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# Simulation of a double layer capacitance and a warburg impedance with comsol

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