Considering that they can contain ingredients like nickel-cadmium, alkaline, and mercury, batteries represent a potentially dangerous form of waste. For this reason, it’s no wonder that researchers are busy trying to come up with environmentally future-friendly batteries, which could one day be used to power similarly biodegradable devices.
That’s where a new project from Binghamton University, State University of New York, comes into the picture. Scientists there have been working to develop a new type of paper-based battery, which is powered by electron-harvesting bacteria. The battery is composed of waxed paper, printed with thin layers of metals and polymers. These hold a type of freeze-dried bacteria called exoelectrogens, which are capable of harvesting electrons and then using them to provide power. The batteries also contain a pouch of liquid bacteria food. When the battery is squeezed, the liquid comes into contact with the bacteria, thereby causing the battery to start functioning.
The innovative project comes from the lab of Professor Seokheun Choi, whose work we have previously covered on a couple of occasions. Choi’s earlier battery projects include a stretchy, textile-based, bacteria-powered bio-battery, and a paper-like microbial fuel cell which produces electricity when activated by saliva.
At present, the new paper battery is capable only of powering low-power devices, such as miniature calculators or LED lights. Each battery has a shelf life of around four months and can provide power for a period of up to two days. In the future, the team hopes that it will be possible to extend this so that it can help power medical technologies. One possible way to achieve this might be to stack multiple paper batteries on top of one another, or potentially to create multiple batteries on one long sheet, which could then be folded. Given the growing amount of biomedical research projects involving ingestible biosensors, it is easy to see where a biodegradable battery such as this one would find a home.
Because of what a major game-changer this could be if executed correctly, we will certainly be following the future development of this project with interest. The research was recently presented at a meeting of the American Chemical Society in Boston.