If you’ve ever struggled to fold paper into the shape of a flying crane, you’ll already be familiar with origami. But Seokheun Choi, an engineer at Binghamton University in the US, has created something a little more unusual out of folded paper: a battery.
The size of a matchbook, and costing just five cents (three pence) to produce, each battery consists of several carbon and nickel contacts arranged on a piece of ordinary office paper. When the paper is folded, the contacts are connected, and the battery powers up.

Its cheap construction and simple design make the origami battery an attractive solution to the challenge of powering equipment in more remote parts of the developing world.

“Paper is cheap and it’s biodegradable,” says Choi, “and we don’t need external pumps or syringes because paper can suck up a solution using capillary force.”

Activating the battery simply requires dipping the paper in a drop of unsterilised liquid, such as the water found in a stream. The battery's energy comes from the respiration of bacteria inside this liquid.

“Dirty water has a lot of organic matter,” explains Choi. “Any type of organic material can be the source of bacteria.”

Choi has already shown that folding the paper to connect four sets of contacts in series can light a small LED. He hopes that the batteries may be used in self-contained, paper biosensors that, unlike most current devices, could operate independently of additional power sources.

The invention could be a game changer in the medical world, allowing health workers to carry out diagnostic tests in areas without access to electricity.

Maybe it's time to get practising those cranes, then.

Source: sciencefocus.com