All batteries don’t power electric cars or store energy from renewable sources. Some provide small amounts of power to operate an LED or a medical sensor — functions that can make a critical difference to people living in remote areas far from any electrical grid.
Researchers from the State University of New York at Binghampton will present their work on a groundbreaking paper battery powered by bacteria at the American Chemical Society this week.
Disposable paper-based biosensors already exist for detecting diseases, monitoring health conditions, and detecting environmental contaminants but having access to an external source of power would significantly increase their diagnostic capabilities.
The search for inexpensive, disposable batteries to supply the power needed is what led Choi and his team to pursue their quest to develop inexpensive paper batteries powered by bacteria.
The paper battery is made by printing thin layers of metals and other materials onto a paper surface followed by adding a layer of freeze dried exoelectrogens — a special type of bacteria that transfer electrons through their cell walls.
When those electrons make contact with external electrodes, they create enough electrical energy to power the battery. We aren’t talking about a lot of electricity here, just enough to power a light emitting diode, a biosensor, or a calculator, but in places where other sources of electricity are simply unavailable, that tiny current can be enough to make a life saving difference. 
The bacteria are activated by a small amount of water. Even saliva can bring the bacteria to life in a matter of minutes. The bacteria currently can survive about 4 months in their freeze dried state. The researchers continue to look for ways to extend the shelf life of their new paper batteries, which are used once and then discarded.
“Sophisticated sensors require a power supply. Commercial batteries are too wasteful and expensive, and they can’t be integrated into paper substrates. The best solution is a paper-based bio-battery.”
Reference- Cleantechnica, ScienceDaily