PORTLAND, Ore. A paper battery based on carbon nanotubes and silver nanowires could store an electric charge in a mobile device. Researchers also claim the new battery is disposable and that its shape could conform to the shape of different devices.
|Bing Hu, a Stanford Univeristy post-doctoral fellow, applies special ink to ordinary paper, depositing nanotubes on the surface that can then be charged to create a battery.|
A Stanford University researcher said his team has demonstrated conductive coatings for battery components ranging from supercapacitors to inexpensive electrodes. The process could be commercially available in several years, according to Yi Cui, a Stanford assistant professor of materials science and engineering.
"Paper can now be used as a substrate to make functional conductive electrodes," the Stanford researcher said.
The conductive paper was prepared by coating it with a special nano-ink solution containing carbon nanotubes and silver nanowires, which assemble into a thin film of one-dimensional structures that adhere to the fibrous paper surface. The coated sheet of paper became a highly conductive storage device, which the researchers charged, then connected to power light-emitting diodes.
Batteries can store a charge longer than capacitors but cannot supply as much current per unit of time. Stanford's conductive paper could be used to build either type, but the researchers claim that its high conductivity and high surface-to-volume ratio could enable supercapacitors for electric cars, which depend on quick jolts of electricity during acceleration.
The researchers also predict that paper storage devices could be used in massive arrays to store excess energy from power grids at night, then redistribute it during the day.
In tests, the Standford researchers were able to charge and discharge the paper battery up to 40,000 times, a 10-fold increase over conventional lithium-ion batteries.