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Super super capacitor:?

Started by Jan Panteltje December 30, 2012
Super super capacitor:
 http://www.sciencedump.com/content/super-supercapacitor
A traditional supercapacitor is basically two hunks of activated charcoal 
floating in electrolyte.  Due to ions in solution and properties of the 
surface, an electric bilayer forms around the surface of the charcoal 
(which has a *lot* of surface), which resists current flow over a certain 
range: it has a deadband within which the layer is stable.  This voltage 
is about 1.2V for water, but the organic solvents used in supercapacitors 
tolerate up to 2.8V or so.  That's pretty remarkable, chemically, when you 
consider it's the same voltage a hunk of magnesium achieves while 
dissolving in water!

The main downsides are, activated charcoal is a crude material, and though 
it has a lot of surface area, it isn't very well connected (ESR depends on 
the average path length to any given point in the mass), so the 
resistivity is way worse than, say, a conventional metallic electrode 
(electrolytic or film types), and the performance nowhere near a 
battery's.

Indeed, one can easily build a supercapacitor at home: press a cake of 
charcoal against a graphite terminal for each electrode, sandwich two 
electrodes around a paper divider, and moisten with salt water.  Several 
farads can be easily achieved, but the average ESR is so massive, it takes 
minutes to fully charge or discharge!  The best commercial products 
basically address this with very thin layers of electrode, spiral 
construction, high conductivity electrolyte, and probably some special 
processing on the charcoal.

The holy grail would be, say, alternating graphite sheets connected to 
each electrode, just like a stacked film capacitor, on the nano scale. 
This could be made extremely small (assuming it could be made at all).  A 
less aggressive approach might use wads of graphite (graphene paper, 
perhaps), rolled up much like an electrolytic.  This might be closer to 
what they're demonstrating.

Ultimately, since we're talking separation of charge, no type of capacitor 
can ever achieve the energy density of a battery (which still works on 
separation of charge, but on the atomic scale, not molecular or higher). 
That said, today's batteries, though constantly improving, are probably on 
par with an ideal theoretical capacitor, so there is plenty of room for 
improving both.

Tim

-- 
Deep Friar: a very philosophical monk.
Website: http://seventransistorlabs.com

"Jan Panteltje" <pNaonStpealmtje@yahoo.com> wrote in message 
news:kbp2kd$6q3$1@news.albasani.net...
> Super super capacitor: > http://www.sciencedump.com/content/super-supercapacitor
On Dec 30, 4:47=A0am, Jan Panteltje <pNaonStpealm...@yahoo.com> wrote:
> Super super capacitor: > =A0http://www.sciencedump.com/content/super-supercapacitor
Cool video. "Ric Kaner set out to find a new way to make graphene, the thinnest and strongest material on earth. What he found was a new way to power the world." Right. To match gasoline, he needs 35MJ/L, or about 11kF/cm^3 for a 2.5v cap. They're getting 20F/cm^3. So, it only has to be 550x better. If lead-acid batteries were 550x better, you'd only need 5kg of 'em for a pretty decent car. -- Cheers, James Arthur
<dagmargoodboat@yahoo.com> wrote in message 
news:1519bd1d-7551-4ddc-b157-e9394a744d24@w8g2000yqm.googlegroups.com...
On Dec 30, 4:47 am, Jan Panteltje <pNaonStpealm...@yahoo.com> wrote:
> Super super capacitor: > http://www.sciencedump.com/content/super-supercapacitor
Cool video. "Ric Kaner set out to find a new way to make graphene, the thinnest and strongest material on earth. What he found was a new way to power the world." Right. To match gasoline, he needs 35MJ/L, or about 11kF/cm^3 for a 2.5v cap. They're getting 20F/cm^3. So, it only has to be 550x better. If lead-acid batteries were 550x better, you'd only need 5kg of 'em for a pretty decent car. -- Until it comes time to charge it.
On Sun, 30 Dec 2012 09:47:47 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:

>Super super capacitor: > http://www.sciencedump.com/content/super-supercapacitor
The research (and funding) soon follows: <http://www.bbc.co.uk/news/science-environment-20846282> "... will work with industrial partners including Nokia, BAE Systems, Procter & Gamble, Qinetiq, Rolls-Royce, Dyson, Sharp and Philips Research - which will together bring in a further &#2013266083;12m in investment." I can see it now... A graphene powered cell phone (Nokia), with military applications (BAE), which will do the laundry (PG and QinetiQ), power the Rolls-Royce electric luxury car, run an electric vacuum cleaner (Dyson), run a 3D TV (Sharp), and power an off grid LED lamp (Philips). More power to the conglomeration. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
On Sun, 30 Dec 2012 16:32:26 -0800 (PST), dagmargoodboat@yahoo.com
wrote:

>If lead-acid batteries were 550x better, you'd only need 5kg of 'em >for a pretty decent car.
Perhaps it would be best to start with smaller applications before taking on the electric car problem. For example, I could certainly use longer battery run time and life for my smartphone and laptop: <http://www.graphene-info.com/smcs-new-revolutionary-graphene-based-energy-devices> <http://www.graphene-info.com/graphene-and-silicon-sheets-used-make-lithium-ion-batteries-10-times-capacity-and-charge-speed> -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
On Dec 30, 9:11=A0pm, Jeff Liebermann <je...@cruzio.com> wrote:
> On Sun, 30 Dec 2012 16:32:26 -0800 (PST), dagmargoodb...@yahoo.com > wrote: > > >If lead-acid batteries were 550x better, you'd only need 5kg of 'em > >for a pretty decent car. > > Perhaps it would be best to start with smaller applications before > taking on the electric car problem. =A0For example, I could certainly > use longer battery run time and life for my smartphone and laptop: > <http://www.graphene-info.com/smcs-new-revolutionary-graphene-based-en...= > > <http://www.graphene-info.com/graphene-and-silicon-sheets-used-make-li...= >
The actual performance data, notably absent, is eagerly anticipated by all. -- Cheers, James Arthur
On 2012-12-30, Tim Williams <tmoranwms@charter.net> wrote:

> The holy grail would be, say, alternating graphite sheets connected to > each electrode, just like a stacked film capacitor, on the nano scale. > This could be made extremely small (assuming it could be made at all). A > less aggressive approach might use wads of graphite (graphene paper, > perhaps), rolled up much like an electrolytic. This might be closer to > what they're demonstrating.
perhaps cabon nanotubes instead of charcoal sponge. graphene whilst thin has no more surface area than the aluminium foil you're replacing with it . -- &#9858;&#9859; 100% natural
On Sun, 30 Dec 2012 19:29:06 -0800 (PST), dagmargoodboat@yahoo.com
wrote:

>On Dec 30, 9:11&#2013266080;pm, Jeff Liebermann <je...@cruzio.com> wrote: >> On Sun, 30 Dec 2012 16:32:26 -0800 (PST), dagmargoodb...@yahoo.com >> wrote: >> >> >If lead-acid batteries were 550x better, you'd only need 5kg of 'em >> >for a pretty decent car. >> >> Perhaps it would be best to start with smaller applications before >> taking on the electric car problem. &#2013266080;For example, I could certainly >> use longer battery run time and life for my smartphone and laptop: >> <http://www.graphene-info.com/smcs-new-revolutionary-graphene-based-en...> >> <http://www.graphene-info.com/graphene-and-silicon-sheets-used-make-li...> > >The actual performance data, notably absent, is eagerly anticipated by >all.
Real numbers will eventually appear, but only after research and startup funding arrives. Meanwhile, amazing claims of spectacular performance will predominate. Real products? No problem: <http://g3ar.co.za/wp-content/uploads/2012/03/Graphene-battery.jpg> I found this attempt to produce usable numbers. <http://hackaday.com/2012/03/20/print-your-own-supercaps/> Never mind the article. The confusion is in the readers comments, which like your numbers, didn't include any useful references or sources. There was originally two papers on the topic (probably with usable numbers) that were attached to the story, but the links don't work. This is as close to real numbers as I could find: "Graphene-Based Ultracapacitors" <http://bucky-central.me.utexas.edu/RuoffsPDFs/179.pdf> Unfortunately, they provide only Farads/gram, which isn't particularly useful. Meanwhile, progress in storage technology has found a possible solution to making practical lithium-sulfur batteries, which can then be labeled as having "natural" and "organic" sources: <http://www.rsc.org/chemistryworld/News/2011/January/18011101.asp> Then, there's the see through battery: <http://www.gizmag.com/go/7018/> Many such promising technologies die a silent death in the research lab as unforeseen difficulties and complications emerge during the development. 20 years later, they are then resurrected by someone able to solve these difficulties, and emerge as the next miracle products. Have patience please. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
On Sun, 30 Dec 2012 18:11:14 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>On Sun, 30 Dec 2012 16:32:26 -0800 (PST), dagmargoodboat@yahoo.com >wrote: > >>If lead-acid batteries were 550x better, you'd only need 5kg of 'em >>for a pretty decent car. > >Perhaps it would be best to start with smaller applications before >taking on the electric car problem. For example, I could certainly >use longer battery run time and life for my smartphone and laptop: ><http://www.graphene-info.com/smcs-new-revolutionary-graphene-based-energy-devices> ><http://www.graphene-info.com/graphene-and-silicon-sheets-used-make-lithium-ion-batteries-10-times-capacity-and-charge-speed>
Actually, laptops are getting better. Lately I've been seeing 13H battery life advertised, 24H with the additional (attached) battery "slice". My new one (not one of the above) is running just short of 6H but it's still learning the battery.