Low cost disposable fuel cell to power biosensors

By Nick Flaherty www.flaherty.co.uk

Researchers in the US have developed a low cost disposable microbial fuel cell (MFC) that that generates power from a few drops of water, says EETimes Europe. The cell could cost just $0.70 to produce to drive more powerful biosensors.

Having a battery that can be powered by the microbes in waste water opens up new opportunities for installing sensors in harsh environments as part of the Internet of Things (IoT).

The cell was developed by Seokheun “Sean” Choi, assistant professor of electrical and computer engineering at Binghamton University, New York. Along with two students, he developed a module measuring 6cm across, following an earlier prototype.

“Last time, it was a proof of concept. The power density was in the nanowatt range,” said Choi. “This time, we increased it to the microwatt range. We can light an LED for about 20 minutes or power other types of biosensors.”

The battery could allow the use of more sophisticated fluorescent or electrochemical biosensors in developing countries, he said. “Commercially available batteries are too wasteful and expensive for the field,” he says. “Ultimately, I’d like to develop instant, disposable, accessible bio-batteries for use in resource-limited regions.”

The new design folds into a star with one inlet at its centre and the electrical contacts at the points of each side. After a few drops of dirty water are placed into the inlet, the device can be opened into a Frisbee-like ring to allow each of the eight fuel cells to work. Each module is a sandwich of five functional layers with its own anode, proton exchange membrane and air-cathode.

Choi’s original matchbook-sized battery could be produced for about 5 cents. The new ninja star device is more expensive — roughly 70 cents — as it uses carbon cloth for the anode as well as copper tape. The team’s next goal is to produce a fully paper-based device that has the power density of the new design and a lower price tag.