Clean tech innovations have long borrowed from the ancient art of origami. The folding techniques let inventors create small, but strong devices out of thin materials and it can be seen in everything from LEDs to solar arrays.
The most recent example is a new paper battery from researchers at Binghampton University that folds into the size of a matchbook and runs on bacteria provided by dirty water. Origami allowed the inventors to create three-dimensional, stackable battery structures that provide more power than two-dimensional versions.
The battery works by harvesting energy from the microbial respiration of bacteria which provides enough power to run a biosensor with just a drop of dirty water.
"Dirty water has a lot of organic matter,” Binghamton University engineer Seokheun “Sean” Choi says. “Any type of organic material can be the source of bacteria for the bacterial metabolism.”
This battery could have a host of applications in developing areas where it could power biosensors that test for diseases and, the best news, it's cheap. The materials -- paper, inexpensive cathodes and anodes and dirty water -- amount to just 5 cents per battery.
“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.”
The battery uses an inexpensive air-breathing cathode made with nickel sprayed onto one side of ordinary paper, while the anode is screen printed with carbon paints and repels water with wax boundaries. The bacteria-filled water can come from a variety of sources including local wastewater, biomass or watersheds.
The easily attained materials have gotten the technology some positive attention. Paper biosensors have so far needed to be paired with a hand-held device for analysis, but Choi wants to create a fully self-powered system where the paper battery would fully run the biosensor. To reach this goal, he has received a $300,000 grant from the National Science Foundation.