Super-Duper-Uber Capacitors On The Way!!

[valveitude]

The boys at MIT are developing a new family of ultra-caps with a storage density 50% of a lead-acid battery!! They accomplish this with the use of carbon nanotubes...


Photo: Riccardo Signorelli/MIT

From the article..The Charge of the Ultra-Capacitors

"By virtue of their dimensions, it struck me that those nanotubes held the promise of even higher porosity than the activated carbon used in commercial ultracapacitors. Together the nanotubes have an enormous surface area, and their dimensions are more uniform than those of the activated-carbon pores, making them more like a paintbrush than a sponge."

Casey

[ak_47_boy]

I doubt it is possible to produce these at a reasonable cost.

[scott wurcer]

Never underestimate the smell of money. I saw last week that Toshiba is selling HD DVD players for $99.99. The blue laser optical components had everyone scratching their heads only a couple of years ago.

[john curl]

Nanotubes are the next revolution!

[auplater]

But.. won't they sound "fuzzy and congested"?? what with all that "density" and such???

Or perhaps the music will be "painted over a broad landscape awash with vibrant colors and textures attributed to the micro-fine ciliary structures"...

John L.

[BWRX]

"Another advantage of nanotubes over activated carbon is that their structure makes them less chemically reactive, so they can operate at a higher voltage."

One major roadblock for current ultracaps are the low voltage ratings. Higher voltage ratings would really make these things take off.

[SY]

Of course that's partially offset by the smaller structural geometry, meaning more "pointy" stuff with stronger fields for the same potential. Still and all, nanotubes do look really interesting, especially for structures that can take advantage of their anisotropy.

[JohnG]

These caps are "super-capacitors," otherwise known as double-layer capacitors, and there operational principle falls somewhere between a battery and a capacitor. I forget the physics and chemistry, but they are not an electrostatic capacitor. the upshot is that they have an effective ESR that increases dramatically, and non-linearly, with frequency. They are also inherently low-voltage devices (~2-4V), since higher voltages will start an electrochemical reaction, ending the device's proper operation.

Note that you can already buy double-layer capacitors, even from Digi-key I think.

John

[valveitude]

They are also inherently low-voltage devices (~2-4V), since higher voltages will start an electrochemical reaction, ending the device's proper operation.

From article..

Another advantage of nanotubes over activated carbon is that their structure makes them less chemically reactive, so they can operate at a higher voltage. And certain types of nanotubes, depending on their geometry, can be excellent conductors—which means they can supply more power than ultracapacitors outfitted with activated carbon.

[scott wurcer]

Somewhere else they actually mention a 300V target for super-capacitors and go on to say they have already solved the safety issues (which I am more skeptical of). Think many mega-joules charged to lethal voltages crushed in an accident. They also dismiss the several thousand amp currents that it would take to charge the thing in the claimed time as "no problem".