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A Non-Toxic, Paper Battery / Supercapacitor
jcr 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.
Instead of a paper-cut you get a electric paper-shock?
This is a pointless announcement. Anybody can make a capacitor with two conducting surfaces separated by an insulator. A good, useful, and economical capacitor is something else. Questions like capacitance, capacitance per unit area, capacitance per unit volume, voltage rating, Q, stability, cost per unit, testability, long-term stability and reliability, manufacturability, testability, structural strength, vibration effects, electromigration, overvoltage resistance, pinhole noise, dielectric drift, leakage current, leakage drift, stray inductance, longevity, temperature range, polarization, memory effect, moisture resistance, solvent resistance, altitude effects, and more are significant parameters. A useful new capacitor design would have to have some significant advantages over current designs.
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 , laser ablation http://en.wikipedia.org/wiki/Laser_ablation and arc discharge http://en.wikipedia.org/wiki/Arc_discharge.
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.
Power capacity. Keith Dawson, it's anything BUT that. Power capacity would be the ability to discharge. The poster is probably thinking of energy density. PLEASE READ THE SUBMISSIONS (and maybe try to understand them if you can) BEFORE YOU POST THEM ON THE FRONT PAGE.
Where are the numbers? As in how many microFarads per cubic centimeter does this material hold? As in how many milliAmp/hours? Without any numbers this is just science fiction, or a slow day at journalism school.