A paper battery is a flexible, ultra-thin energy storage and production device formed by combining carbon nanotube s with a conventional sheet of cellulose-based paper. A paper battery acts as both a high-energy battery and supercapacitor , combining two components that are separate in traditional electronics . This combination allows the battery to provide both long-term, steady power production and bursts of energy. Non-toxic, flexible paper batteries have the potential to power the next generation of electronics, medical devices and hybrid vehicles, allowing for radical new designs and medical technologies.
Paper batteries may be folded, cut or otherwise shaped for different applications without any loss of integrity or efficiency . Cutting one in half halves its energy production. Stacking them multiplies power output. Early prototypes of the device are able to produce 2.5 volt s of electricity from a sample the size of a postage stamp
They have produced a sample slightly larger than a postage stamp that can store enough energy to illuminate a small light bulb. But the ambition is to produce reams of paper that could one day power a car.
Professor Robert Linhardt, of the Rensselaer Polytechnic Institute, said the paper battery was a glimpse into the future of power storage. The team behind the versatile paper, which stores energy like a conventional battery, says it can also double as a capacitor capable of releasing sudden energy bursts for high-power applications.
How a paper battery works
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.
The research appears in the Proceedings of the National Academy of Sciences (PNAS).
"Think of all the disadvantages of an old TV set with tubes," said Professor Linhardt, from the New York-based institute, who co-authored a report into the technology.
"The warm up time, power loss, component malfunction; you don't get those problems with integrated devices. When you transfer power from one component to another you lose energy. But you lose less energy in an integrated device."
The battery contains carbon nanotubes, each about one millionth of a centimetre thick, which act as an electrode. The nanotubes are embedded in a sheet of paper soaked in ionic liquid electrolytes, which conduct the electricity. The flexible battery can function even if it is rolled up, folded or cut. Although the power output is currently modest, Professor Linhardt said that increasing the output should be easy.