Ordinary paper can be turned into a battery electrode simply by dipping it into carbon-nanotube inks. The resulting electrodes, which are strong, flexible, and highly conductive, might be used to make cheap energy storage devices to power portable electronics.
|Nanotube ink: This piece of office paper has been painted with black carbon nanotube ink. |
It's now possible to print lightweight circuits and screens for electronics like e-readers, but conventional batteries still weigh these devices down. Carbon nanotubes are a promising material for printing batteries because, in addition to their strength, light weight, and conductivity, they can store a large amount of energy--a quality that helps portable electronics run longer between charges.
Now a group of Stanford University researchers, led by materials science professor Yi Cui, have demonstrated that ordinary office paper soaks up carbon nanotubes like a sponge and can be turned into electrodes for batteries and supercapacitors. The advantage of paper, says Cui, is that it's cheap and interacts strongly with nanotubes without the need for putting additives in the ink. "We take advantage of the porous structure of paper," says Cui. "Carbon nanotubes absorb into the paper and stick on really tightly."