A Non-Toxic, Paper Battery / Supercapacitor

A user writes "Researchers at Rensselaer Polytechnic Institute have developed a combination battery/capacitor by infusing carbon nanotubes and electrolytes into a paper substrate. The material can be folded, rolled up, or molded to any convenient shape with no effect on power capacity. Operating temperature range is -100 to 300 degrees F. One of the co-authors is quoted: 'We're not putting pieces together — it's a single, integrated device. The components are molecularly attached to each other: the carbon nanotube print is embedded in the paper, and the electrolyte is soaked into the paper. The end result is a device that looks, feels, and weighs the same as paper.'" The researchers haven't yet developed a high-volume way to manufacture the devices. They envision ultimately printing sheets between rollers like newsprint.

in SI units

[Anonymous Cowpat]

thats -73.3 C to 148.8 C.

<\karma whore>

Re:Your purpose, Mr. Anderson?

[Anonymous Coward]

no, it doesn't. It might raise the question, but most definitely does not beg.

Re:How hard are nanotubes to create?

[Anonymous Coward]

imperfect ones are found in ordinary soot. Their effectiveness drops of rapidly if even just a few flaws are introduced and as far as I'm aware the only way of geting them with a really low flaw-count is to deliberately manufacture them.

Re:How hard are nanotubes to create?

[KrugalSausage]

I do some research with CNTs, so maybe I can help answer this.

Carbon nanotubes are not completely unnatural, there is probably a very small percentage found in your fireplace (if you are burning carbon based wood, is there another kind? ;) ).

Most methods of production involve taking some form of carbon and applying enough energy to it break it up and allowing it to reform. In the 1950's, some Russian researchers were first publishing about these very small and strange carbon rods that they found in their powder. Going from memory (don't know russian), I believe they started with some electrodes with carbon on them. After applying high voltage to them, a discharge (lightning) forms and breaks down the carbon. In this soot, some of these carbon nanotubes were found. They were unaware of the significance of their discovery at the time.

In 1991, Iijima published their 'new' discovery (not knowing about the Russian paper, language barrier and all) of the CNT and since then, research has exploded into finding and refining new ways to make them. Their method of production involved laser ablation, where a carbon target is hit with a laser. The hot debris is carried by an inert gas and while it cools some nanotubes are formed.

The three main methods are chemical vapor deposition http://en.wikipedia.org/wiki/Chemical_vapor_deposi tion [wikipedia.org] , laser ablation http://en.wikipedia.org/wiki/Laser_ablation [wikipedia.org] and arc discharge http://en.wikipedia.org/wiki/Arc_discharge [wikipedia.org].

Now there are companies that can send you a black powder that is >95% carbon nanotubes. At our lab, we take these and mix them with a surfactant to make a CNT solution. If you filter this solution, the CNTs accumulate on top of the filter and form a black sheet of carbon nanotubes. This paper paper goes by the name of buckypaper. In the article, it seems that instead of a surfactant they are using cellulose. If you want them to align while they are forming the paper, all one has to do is apply an external electric field. The quasi-one dimensional nature of the CNTs gives them a higher magnetic susceptibility along their axis than perpendicular to it. This helps them align along the magnetic field lines.

Re:How hard are nanotubes to create?

[Apatharch]

Carbon nanotubes are usually manufactured by vaporising graphite impregnated with metal particles. The carbon condenses on the metal, forming tubular molecules. There's more information on the process here [azonano.com].

Re:How hard are nanotubes to create?

[peragrin]

I forgot the name of the paper I read just last night and I am at the wrong computer to look up the history, but Scientists have discovered that Damascus sword blades actually have formed carbon nano tubes in them. While the forgers of Damascus blades didn't know what they did they did know it worked better than plain old steel.

Re:e-ink

[vigmeister]

Here's a link to printable RFIDs

ahref=http://www.physorg.com/news2678.htmlrel=url2 html-19118 [slashdot.org]http://www.physorg.com/news2678.html>

P.S. Wearable computers make you look like a borg - Look at pics of Thad Starner for example
ahref=http://www.cc.gatech.edu/~thad/rel=url2html- 19118 [slashdot.org]http://www.cc.gatech.edu/~thad/>

Cheers!

Re:e-ink

[vigmeister]

Sorry... Slashdot messed up my links

Printed RFIDs [physorg.com]

Thad Starner is a Borg [gatech.edu]

Cheers!

No, it's not.

[morgan_greywolf]

Actually, the point everyone is missing is this, FTFA:

Another key feature is the capability to use human blood or sweat to help power the battery.

Three uses for this, right off the bat:

• Ultra-small/portable blood glucose meters. I don't know how many of you are diabetic, but my wife is and I can tell you that carrying around a blood glucose meter is a real PITA. Anything that has the potential to make these things smaller and more portable is a real plus.
• E-ink/e-paper. Imagine having the thing turn on as soon as you grab it. Cool!
• Low footprint biometric systems. Let's face it, having a biometric identification system is more practical if you can get a device that fits where you need it.

Re:How hard are nanotubes to create?

[Grifty]

Actually, there is a very interesting article in Nature describing this.
http://www.nature.com/news/2006/061113/full/061113 -11.html [nature.com]

Re:Where's the numbers, fool?

[Anonymous Coward]

"So far, the researchers have achieved power densities of 1.5 kilowatts per kilogram in the supercapacitor version and tested it over 100 cycles of discharge and recharge, well short of the million or so typical for current commercial capacitors."

source [sciam.com]

Re:Where's the numbers, fool?

[Anonymous Coward]

"By putting two sheets of paper together with the cellulose side facing inwards (and a drop of electrolyte on the paper), a supercapacitor is formed. These supercapacitors retain the flexibility of normal paper, but they have a rating that is comparable to that of standard commercial hardware--a 100g sheet could replace a 1300mAh battery. Because the medium is flexible, the researchers say you could shape batteries of all sizes for very specific use.

It doesn't stop there, however. By putting a drop of electrolyte on a single sheet and then putting a metal foil consisting of lithium and aluminum on each side, a lithium ion battery is formed. This paper device had a respectable 110mAh/g capacity, and the researchers indicate that small prototypes could already power small mechanical devices like fans. These batteries and supercapacitors are quite stable and have been shown to operate over a wide range of temperatures, with the research showing that they can operate between -78-150C. "

From: http://arstechnica.com/news.ars/post/20070813-scie ntists-create-paper-thin-flexible-biodegradable-ba ttery.html [arstechnica.com]