A bacteria-powered battery that can power disposable electronics has been created on a single sheet of paper. The manufacturing technique reduces fabrication time and cost, and the design could revolutionize the use of bio-batteries as a power source in remote, dangerous, and resource-limited areas.
Called “papertronics,” the battery is a simple and low-cost way to power point-of-care diagnostic sensors — self-sustained, paper-based, point-of-care devices that provide effective, lifesaving treatments in resource-limited settings.
A ribbon of silver nitrate is placed underneath a thin layer of wax to create a cathode on one half of a piece of chromatography paper. A reservoir is then made from a conductive polymer on the other half of the paper, which acts as the anode. Once properly folded, a few drops of bacteria-filled liquid are added, and the microbes’ cellular respiration powers the battery.
The device requires layers to include components such as the anode, cathode, and proton exchange membrane (PEM). The final battery requires manual assembly, leading to potential issues including misalignment of paper layers, and vertical discontinuity between layers, which ultimately decreases power generation.
Different folding and stacking methods can significantly improve power and current output. Tests of the device generated 31.51 microwatts at 125.53 micro-amps with six batteries in three parallel series, and 44.85 microwatts at 105.89 microamps in a 6 × 6 configuration.
It would take millions of paper batteries to power a 40-watt light bulb, but on the battlefield or in a disaster situation, usability and portability are most important. The battery generates enough power to run biosensors that monitor glucose levels in diabetes patients, detect pathogens in the body, or perform other lifesaving functions.
The system enables paper-based microbial fuel cell technology in which microorganisms harvest electrical power from any type of biodegradable source, such as wastewater, that is readily available.