This latest biobattery comes from a long list of projects by Binghamton University professor Seokheun Choi, who has been experimenting with bacteria-based paper batteries for years. These batteries come in the shape of a matchbox, a ninja star, an accordion folded paper, and even a stretchy wearable fabric. The bacteria commonly used in these devices generate electricity as a byproduct of their respiration and feed on nutrients in their environment — even saliva or sweat.
One drawback they face, however, is longevity, for which Choi set out in the new study to create longer-lasting biobatteries by combining multiple bacterial species that support each other.
The team stacked chambers containing different bacteria in three layers. On the top layer are photosynthetic bacteria, which harvest energy from sunlight to produce organic molecules that feed the bugs in the layer below. The bacteria in the bottom layer generate electricity by eating nutrients produced by the bacteria in the middle layer.
The team tested versions of these biobatteries, which measure 3 square centimeters. They found that the battery could generate electricity for weeks at a time. This could allow them to operate small sensors or electronics in remote areas without human supervision. The current version of the biobattery doesn’t produce a lot of electricity, but the team says the output could be increased by adding more cells.
Work on future versions will focus on enabling them to float on water and repair themselves when damaged, Choi said.