Binghampton University, New York, is joking that "instead of ordering batteries by the pack, we might get them by the ream in the future." Researchers at the institution have revealed a battery, powered by bacteria, imprinted upon a sheet of paper. The research team asserts that its thin new papertronic batteries "could revolutionize the use of bio-batteries," and become an essential part of disposable electronic devices in resource-limited settings.
These paper batteries are constructed using a piece of chromatography paper. On one half of the paper a ribbon of silver nitrate is deposited underneath a thin layer of wax to create a cathode. A conductive polymer is used to create a reservoir on the other half of the sheet of paper. The battery becomes active when the paper is folded and a few drops of bacteria-filled liquid are added to the reservoir. It is the microbes' cellular respiration that powers the battery.
The battery output power can be adjusted depending upon the folding and stacking methods of the papertronic sheet. However, power output is rather low. An example output of 31.51µW at 125.53µA with six batteries in three parallel series is cited. Thus it would take millions of the paper batteries to power a 40W light bulb.
On the positive side of things, these batteries could power electronics such as biosensors that monitor glucose levels in diabetes patients, detect pathogens in a body, or perform other life-saving functions. Such biobatteries are a simple and low cost solution to powering disposable point-of-care diagnostic sensors, for example.
One of the researchers involved in the project, Assistant Professor Seokheun 'Sean' Choi, explained his enthusiasm for the paper-based bacteria-powered battery: "We are excited about this because microorganisms can harvest electrical power from any type of biodegradable source, like wastewater, that is readily available. I believe this type of paper biobattery can be a future power source for papertronics".
There's likely plenty of scope for improvements in this development. Choi added that the technology behind this innovation is relatively unexplored and has the potential of a large upside.