Seperator Membrane in Supercapacitor-Electrochemistry

[C'estlavie!]

Hello guys, I've recently started learning about supercapacitors and their principles for an internship im doing right now and I had trouble understanding the seperator which is a porous membrane and its main function is to stop electronic conduction between the capacitor electrodes and prevent a short circuit but allow ionic conduction.

 

So if it is ion permeable why does it stop electrons from passing through as they comparatively smaller than the electrolyte ions. Most of the commercial seperator membranes right now are made from cellulose derivatives or porous polypropylene.

 

Does it have to do anything with the material properties of the membrane? or is it something else?

 

https://en.wikipedia.org/wiki/Electric_double-layer_capacitor-->basic idea of supercapacitor working mechanism.

Any help would be greatly appreciated.

Edited May 23, 2013 by C'estlavie!

[EdEarl]

Try this page: http://en.wikipedia.org/wiki/Supercapacitor

[C'estlavie!]

Thanks for that EdEarl but I had already read that page but it doesnt explain much of what I wanted to know. But on the positive side I found out that in water solutions the solvated electrons exist and are unstable and hence incapable of creating a conduction current and normally only ionic conduction exists.

[EdEarl]

I am no expert, but it sounds like the ions minimize the distance between the two electrodes and assure maximum electrode surface area.