Stanford boffins have worked out a way of using nanotechnology to quickly produce ultra-lightweight, bendable batteries and supercapacitors in the form of everyday paper. Basically all they are doing is coating a sheet of paper with ink made of carbon nanotubes and silver nanowires to make a highly conductive storage device.

Yi Cui, assistant professor of materials science and engineering said that the invention will help society by providing a low-cost, high-performance energy storage device. The paper capacitors hold an electric charge, but for a shorter period of time. However they can store and discharge electricity much more rapidly than a battery.

In his best seller with the catchy title "Highly Conductive Paper for Energy Storage Devices," published online in the Proceedings of the National Academy of Sciences, Cui said that his nanomaterials are a one-dimensional structure with very small diameters. The small diameter helps the nanomaterial ink stick strongly to the fibrous paper, making the battery and supercapacitor very durable.

The paper supercapacitor may last through 40,000 charge-discharge cycles - at least an order of magnitude more than lithium batteries. The nanomaterials also make ideal conductors because they move electricity along much more efficiently than ordinary conductors, Cui said.

A paper battery is more durable because the ink adheres more strongly to paper. What's more, you can crumple or fold the paper battery, or even soak it in acidic or basic solutions, and the performance does not degrade. Cui predicts his paper could be used in the large-scale storage of electricity on the distribution grid. Excess electricity generated at night, for example, could be saved for peak-use periods during the day.