"Papertronics have recently emerged as a simple and low cost way to power disposable point-of-care diagnostic sensors," said assistant professor Seokheun Choi.
On one half of a piece of chromatography paper, the team placed a ribbon of silver nitrate underneath a layer of wax to create a cathode. The pair then made a reservoir out of a conductive polymer on the other half of the paper, which acted as the anode. Once a few drops of bacteria-filled liquid were added and the paper folded, the microbes' cellular respiration powered the battery.
"[The final battery] demands manual assembly, and there are potential issues such as misalignment of paper layers and vertical discontinuity between layers, which decrease power generation," said Choi.
According to the researchers, different folding and stacking methods can significantly improve power and current outputs. Scientists could generate 31.51µW at 125.53µA with six batteries in three parallel series and 44.85µW at 105.89µA in a 6x6 configuration.
The scientists claim it would take millions of paper batteries to power a common 40W light bulb, but that the battery’s usability and portability would be paramount on a battlefield or in a disaster situation. There would also be enough power to run biosensors that could monitor glucose levels in diabetes patients, detect pathogens in a body and perform other life-saving functions.
"Microorganisms can harvest electrical power from any type of biodegradable source, that is readily available, like wastewater,” Choi concluded. “This type of paper bio battery could be a future power source for papertronics."
