Dipping paper in nanotube mixture creates instant battery

Making a battery can be as simple as dunking a biscuit, according to
Stanford scientists.

They have shown it’s possible to dip an ordinary piece of paper into ink infused with carbon nanotubes and silver nanowires, and turn it into a battery or supercapacitor. Crumple the piece of paper, and it still works.

“Society really needs a low-cost, high-performance energy storage device, such as batteries and simple supercapacitors,” said Yi Cui, assistant professor of materials science and engineering.

The flexibility of paper allows for many clever applications. “If I want to paint my wall with a conducting energy storage device, I can use a brush.”

A paper supercapacitor, with its high surface-to-volume ratio, could be especially useful for applications like electric or hybrid cars, which depend on the quick transfer of electricity.

But Cui predicts the biggest impact could be in 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. Wind farms and solar energy systems also may require storage.

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.

Cui’s work appears in the Proceedings of the National Academy of Sciences.