Paper battery

A paper battery is a battery engineered to use a paper-thin sheet of cellulose (which is the major constituent of regular paper, among other things) infused with aligned carbon nanotubes. [cite news | url = http://www.eurekalert.org/pub_releases/2007-08/rpi-bbs080907.php | title = Beyond Batteries: Storing Power in a Sheet of Paper | author = | publisher = Eurekalert.org | date = August 13, 2007 | accessdate = 2008-09-15] The nanotubes act as electrodes; allowing the storage devices to conduct electricity. The battery, which functions as both a lithium-ion battery and a supercapacitor, can provide a long, steady power output comparable to a conventional battery, as well as a supercapacitor’s quick burst of high energy -- and while a conventional battery contains a number of separate components, the paper battery integrates all of the battery components in a single structure, making it more energy efficient.

Development

The creation of this unique nanocomposite paper drew from a diverse pool of disciplines, requiring expertise in materials science, energy storage, and chemistry. In August 2007, a research team at Rensselaer Polytechnic Institute (led by Drs. Robert Linhardt, the Ann and John H. Broadbent Senior Constellation Professor of Biocatalysis and Metabolic Engineering at Rensselaer; Pulickel M. Ajayan, professor of materials science and engineering; and Omkaram Nalamasu, professor of chemistry with a joint appointment in materials science and engineering) developed the paper battery.Senior research specialist Victor Pushparaj, along with postdoctoral research associates Shaijumon M. Manikoth, Ashavani Kumar, and Saravanababu Murugesan, were co-authors and lead researchers of the project. Other co-authors include research associate Lijie Ci and Rensselaer Nanotechnology Center Laboratory Manager Robert Vajtai.

The researchers used ionic liquid, essentially a liquid salt, as the battery’s electrolyte. The use of ionic liquid, which contains no water, means there’s nothing in the batteries to freeze or evaporate. “This lack of water allows the paper energy storage devices to withstand extreme temperatures,” Kumar said. This also gives the battery its ability to function in temperatures up to 300 degrees Fahrenheit and down to 100 below zero. The use of ionic liquid also makes the battery extremely biocompatible; the team printed paper batteries without adding any electrolytes, and demonstrated that naturally occurring electrolytes in human sweat, blood, and urine can be used to activate the battery device. According to Pushparaj “It’s a way to power a small device such as a pacemaker without introducing any harsh chemicals – such as the kind that are typically found in batteries — into the body.”

Durability

The use of carbon nanotubes gives the paper battery extreme flexibility; the sheets can be rolled, twisted, folded, or cut into numerous shapes with no loss of integrity or efficiency, or stacked, like printer paper (or a Voltaic pile), to boost total output. As well, they can be made in a variety of sizes, from postage stamp to broadsheet. “It’s essentially a regular piece of paper, but it’s made in a very intelligent way,” said Linhardt, “We’re not putting pieces together — it’s a single, integrated device,” he said. “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.”

Uses

The paper-like quality of the battery combined with the structure of the nanotubes embedded within gives them their light weight and low cost, making them attractive for portable electronics, aircraft, automobiles, and toys (such as model aircraft), while their ability to use electrolytes in blood make them potentially useful for medical devices such as pacemakers. The medical uses are particularly attractive for medical applications, because they do not contain any toxic materials and can be biodegradable; a major drawback of chemical cells. [cite news | url = http://news.rpi.edu/update.do?artcenterkey=2280 | title = Beyond Batteries: Storing Power in a Sheet of Paper | author = | publisher = RPI | date = August 13, 2007 | accessdate = 2008-01-15] However Professor Sperling cautions that commercial applications may be a long way away, because nanotubes are still relatively expensive to fabricate. Currently they are making devices a few inches in size. In order to be commercially viable, they would like to be able to make them newspaper size; a size which, taken all together would be powerful enough to power a car. [cite news
url = http://news.bbc.co.uk/2/hi/technology/6945732.stm
title = Paper battery offers future power
author =
publisher = BBC News
date = August 14, 2007
accessdate = 2008-01-15]

References

ee also

Power paper