A paper battery is an electric battery designed to use a spacer made up largely of cellulose (the main component of the paper). Incorporates nanoscale structures to act as high surface electrodes to improve conductivity. In addition to being unusually thin, paper batteries are flexible and environmentally friendly, allowing integration into a wide range of products. Its operation is similar to conventional chemical batteries, with the important difference that they are not corrosive and do not require a wide casing.
A paper drum is a flexible and ultrafine energy storage and production device formed by combining carbon nanotubes with a conventional sheet of cellulose-based paper. A paper battery acts as a high energy and supercapacitor battery, combining two components that are separate in traditional electronics. This combination allows the battery to provide long-term, constant power output and power bursts. Non-toxic and flexible paper batteries have the potential to power the next generation of electronic devices, medical devices and hybrid vehicles, allowing radical new designs and medical technologies.
Paper batteries can be folded, cut or otherwise shaped for different applications without loss of integrity or efficiency. Cutting one in half cuts your energy output by half. Stacking them multiplies the output power. The first prototypes of the device are capable of producing 2.5 volts of electricity from a sample the size of a postage stamp.
The devices are formed by combining cellulose with an infusion of aligned carbon nanotubes that are approximately one millionth of a centimeter thick. Carbon is what gives the batteries their black color. These tiny filaments act as the electrode s found in a traditional battery, conducting electricity when the paper comes into contact with an ionic liquid solution. Ionic liquids do not contain water, which means that there is nothing to freeze or evaporate under extreme environmental conditions. As a result, paper batteries can run between -75 and 150 degrees Celsius.
A method of manufacture, developed by scientists of the Polytechnic Institute Rensselaer and MIT, begins with the cultivation of the nanotubes on a silicon substrate and then impregnating the voids in the matrix with cellulose. Once the matrix has dried, the material can be peeled off the substrate, exposing one end of the carbon nanotubes to act as an electrode. When two sheets are combined, with the cellulose sides facing inward, a supercapacitor is formed which can be activated by the addition of the ionic liquid. This liquid acts as an electrolyte and may include salt-laden solutions such as human blood, sweat, or urine. The high content of cellulose (more than 90%) and the lack of toxic chemicals in paper batteries makes the device biocompatible and environmentally friendly, especially when compared to the traditional lithium ion battery used in Many current and portable electronic devices.
The widespread commercial deployment of paper batteries will be based on the development of cheaper manufacturing techniques for carbon nanotubes. As a result of potentially transformative applications in electronics, aerospace, hybrid vehicles and medical science, however, numerous companies and organizations are pursuing the development of paper batteries. In addition to the developments announced in 2007 at RPI and MIT, researchers in Singapore announced that they had developed a paper battery with ionic solutions in 2005. NEC has also invested in R & D in paper batteries for potential applications in its electronic devices.
Specialized paper batteries could act as energy sources for any number of devices implanted in humans and animals, including RFID tags, cosmetics, drug delivery systems and pacemakers. A condenser introduced into an organism could be implanted completely dry and then be exposed gradudally to bodily fluids over time to generate voltage. Paper batteries are also biodegradable, a need that has only been partially addressed with the current methods of electronic recycling and other methods of disposal of electronics increasingly advocated by the green computer movement.
