The likes of paper cranes and paper planes are going to be joined by a more electrifying origami creation. An origami battery. It sounds like something you might give to a stressed engineer to help them calm down. They might be a great source of stress relief, but they are also going to provide a novel way of getting light, cheap electricity to remote locations.
The folding battery is powered with an indiscriminating substance: dirty water. Any liquid that has bacteria in it, water being a common example, contains enough energy to power the battery. “Dirty water has a lot of organic matter,” says Seokheun “Sean” Choi of Binghamton University. “Any type of organic material can be the source of bacteria for the bacterial metabolism.”
Lugging batteries to remote locations and disposing of them safely can be a bit of a headache if you don't have the right resources available. For this reason, the paper technology will be especially useful for scientists who work in remote areas. “Paper is cheap and it’s biodegradable,” Choi says. “And we don’t need external pumps or syringes because paper can suck up a solution using capillary force.”
Another great feature of this device is that it costs a whopping five cents to make. The battery, when folded, is about the size of a matchbook. It can even be made with ordinary office paper. To give the paper its electrifying properties, one side (the cathode) is sprayed with a nickel-based spray. This is the negative section of the battery. The anode, the positively charged side, is printed onto the paper using carbon paints.
The battery isn't powerful enough to power even a humble mobile phone. It's better suited to low-power appliances (in the microwatt range) such as a biosensor or an LED. At the moment, the paper-based biosensors have to be paired with other devices to perform analyses. However, Choi envisions that one day the origami battery will be producing enough power to run a biosensor all on its own. All of these properties make it very attractive to experts working in disease control and prevention, especially in the Global South.
The moment of the battery's creation was an actual “lightbulb moment” for Choi: “I connected four of the devices in series, and I lit up this small LED,” he says. “At that moment, I knew I had done it!” Electrifying.
The battery won't be running cities anytime soon, but it's an exciting step into the world of crinkly circuits.