Washington, Feb 22 (IANS) Researchers have found a way to make lightweight paper batteries and supercapacitors cheaply -- by just dipping paper or fabric in a special ink infused with nanoparticles.

Capacitors, like batteries, store energy, but by electrostatic rather than chemical means, as well as stretchable textiles known as 'eTextiles' - capable of storing energy while retaining mechanical properties of paper or fabric.

The type of nanoparticle used in Stanford University engineer Yi Cui's experimental devices varies according to the intended function of the product.

For instance, lithium cobalt oxide is a common compound used for batteries, while single-walled carbon nanotubes or SWNTs are used for supercapacitors.

Cui, assistant professor of materials science and engineering at Stanford, leads a research group that investigates new applications of nanoscale materials.

The objective, said Cui, is not only to supply answers to theoretical inquiries but also to pursue projects with practical value.

Homes of the future could one day be lined with energy-storing wallpaper. Gadget lovers would be able to charge their portable appliances on the go, simply plugging them into an outlet woven into their T-shirts.

Energy textiles might also be used to create moving-display apparel, reactive high-performance sportswear and wearable power for a soldier's battle gear. The key ingredients in developing these high-tech products are not visible to the human eye.

Nanostructures, which can be assembled in patterns that allow them to transport electricity, may provide the solutions to a number of problems encountered with electrical storage devices currently available on the market, says a Stanford release.

These findings were published online in the Proceedings of the National Academy of Sciences.