Scientists in upstate New York have produced an energy source made out of paper which could power computers and other electronic devices.
Led by Victor Pushparaj at the Rensselaer Polytechnic Institute in Troy, New York, the scientists have developed a device, based on a paper substrate, that can be bent, twisted and folded, making it particularly useful for flexible electronic devices. The energy source is a hybrid battery and supercapacitor created using carbon nanotubes.
The high surface area of these nanotubes can potentially store a large amount of charge, allowing the battery to respond well to peaks of demand. The nanotube supercapacitor then recharges at a more modest rate from the actual lithium-ion components of the battery, which can be made thin and easily manufactured as they don't have to directly bear that peak demand themselves.
According to New Scientist, the team made the carbon nanotube supercapacitors flexible by first growing the nanotubes on top of a silicon substrate "using standard chemical vapour-deposition". They were then dissolved in a mixture of plant cellulose and chloride, which was spread among the nanotubes. After peeling this off the silicon substrate, they were left with a piece of paper tens of micrometres thick, with carbon nanotubes sticking out from one side.
The batteries are not yet good enough to compete with conventional batteries, the magazine reports, so the next step is to experiment with different formulations of the components to improve performance.