Can an ultra-capacitor be built with simple homemade materials?

Question

There is talk of a new generation of capacitors that can store huge amounts of charge, nearing battery-like performance.

Is it possible to be build such a device with simple parts, that could hold capacitance to multi-farad values in a relatively small volume?

Looking for creative techniques, possibilities. (Etching? Materials?)
thanx

looks like we have a decent area calculation, in an answer below...however, what are the tricks to increase the surface area in a small space?

The digikey one below you can buy is interesting, but how is it constructed?

Answer 1

Some of the supercaps use aerogel as a dielectric. I was shown samples of this material several years ago. Almost transparent, so light it practically floats when released in the air...think really really really light weight styrofoam. Some supercapacitors use a carbon impregnated form of this to attain high capacitance. The aerogel material itself is silicon oxide...I think they deposit carbon on it to form electrodes throughout its volume to give electrodes that are close together with very large surface area.

As one answer stated, the capacitance is proportional to the area of the conductors to the distance between the conductors. It is also proportional to the permittivity of the dielectric. Relative permittivity is a dielectrics permittivity relative to free space which is the 8.854 x 10-12 F/m. A high dielectric constant relative to free space combined with very short distance between the conductive surfaces which should also have very high surface area will give large capacitance.

Hope this helps.

Answer 2

There's more to capacitors than just putting two plates together. "Multi-farad values", with small leakage currents; is going to be impossible for the home builder.

You may be able to technically, achieve +1 farad capacitances. But, it won't be able to hold the charge for any noticeable amount of time.

Answer 3

No. If we could, we'd all have them by now. Hydrogen is too volatile for any homemade materials. A fuel cell has to hold the fuel until it is needed and only release the amount needed, and it has to store it in such a way that it is compact and is not going to easily blow up. And hydrogen is really the only thing you'd use a 'fuel cell' for, because other fuels can be transported as liquids.

Answer 4

Not a chance. They use very exotic chemicals and very complex manufacturing techniques. Even a very small (1F, 2.5V) requires pretty advanced construction. Larger caps (1-50F, 16V) are far more complex considering the currents involved and keeping the impedance extremely low. Not really a home project.

A 1.5F, 16V cap on eBay for $50 is a bargain considering the technology you're getting.

Answer 5

Not really. The equation for a parallel plate capacitor is c=e*A/D where e=8.8541878176 × 10^−12 . So you are taking about 2 huge plates that are really close together.

Answer 6

You can make a fairly large capacitor out of copper clad epoxy resin board. Search on Free nitrogen lasers, that's what they are used in. I think Popular Scientific had an article on them.

Answer 7

Just a thought:

If you are familiar with the arc of the covenant described in the bible, do you think it qualifies as a capacitor by design?

Answer 8

You don't build it. you buy it.

Try digikey.

http://www.epcos.com/inf/20/35/ds/B49410B2506Q000.pdf