A team of engineers recently registered success in developing disposable batteries that could be used in tough field locations where small devices are needed. The team developed 2.5-inches wide microbial fuel cells from a few drops of dirty water. This battery works on the bacteria contained in water drops. The previous version of these fuel cells had a paper based origami shape that looked like a matchbook with four modules stacked over each other. The new design, however, comes with better voltage and power with eight batteries connected in a series. The best part is, this design was derived from an origami ninja star.
Professor Seokhuen Sean “Choi” says, “Last time, it was a proof of concept. The power density was in the nanowatt range. This time, we increased it to the microwatt range. We can light an LED for about 20 minutes or power other types of biosensors.” He is a professor of engineering who headed this research in New York at University of Binghamton. Current produced by the Microbial Fuel Cell (MFC) depends mainly on the amount of energy present in wastewater collected for this purpose. The wastewater as fuel source is a very cost-effective method under which the bacteria gather around the anode in form of a biofilm. Slowly, the colony of these bacteria utilizes all the waste and given off electrons and other side-products which causes the flow of current to cathode possible.
Wastewater is a huge and rapidly growing problem, however, its usage in perishable batteries can help in dealing with the problem of dirty water to a larger extent. Choi’s team took this initiative on a small scale and focused their attention on the paper based biosensors. This helped them in reducing inefficient battery usage that is one of the major sources of pollution. The foldable origami star allows a single inlet on its inner center and electrical points of contact on all other sides. The wastewater droplets get placed inside the inlet, the device is then spread open to permit every single fuel cell to work. Every module in this device gets sandwiched between five active later with their own anode, air cathode, and proton exchange membrane.
These paper based biosensors are to be used in important biological tests like HIV and pregnancy tests and will play a role in formation of electrochemical and fluorescent sensors. Choi further adds, “Commercially available batteries are too wasteful and expensive for the field. I’d like to develop instant, disposable, accessible bio-batteries for use in resource limited regions.”
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