Seokheun Choi is an electrical engineer that has made bacteria-powered batteries that have taken on a number of interesting forms, including matchbooks, folding paper and ninja stars.
Now, for the first time, the Binghamton University researcher has woven his innovation fuel cells into a flexible and stretchable piece of fabric that might be able to power wearable electronics through our body's own bacteria.
Choi's bacteria-powered batteries rely on what are known as microbial fuel cells (MFCs). These types of cells use bacteria to trigger reduction/oxidation reactions, which swap electrons between molecules to generate electricity.
"Among many flexible and integrative textile-based batteries and energy storage devices, MFCs are arguably the most underdeveloped for wearable electronic applications because microbial cytotoxicity may pose health concerns," Choi told an online source. "In the literature, reported work on the wearable MFCs was either unavailable or quite limited. However, if we consider that humans possess more bacterial cells than human cells in their bodies (3.8×10 13 compared to 3.0×10 13), the direct use of bacterial cells as a power resource interdependently with the human body is conceivable for wearable electronics."
Choi investigated the possibilities by building his MFCs into a twistable, stretchable textile-based battery that uses the bacteria Pseudomonas Aeruginosa as a catalyst. The resulting device has a maximum power output of 6.4 µW cm−2, which is similar to one of his other inventions, a paper-based MFCs. The results also demonstrate stable, lasting performance even when bent out of shape repeatedly.
Choi explains: "All my previous experiences and technologies on paper-based bio-batteries have been leveraged to develop for the first time an entirely textile-based bio-battery," Choi told the online source. "All battery components were monolithically incorporated into a single sheet of fabric by precisely controlling the depth of each component. The structure consisted of the anode and cathode placed in a single reaction chamber with no separating membrane. The anodic chamber was specifically engineered to be conductive and hydrophilic for electricity harvesting from bacterial cells in liquid, while the cathode used the silver oxide and silver redox couple as a solid-state material for textile-based electronics."
An advantage of the single-chamber membrane-free approach, which is a departure from typical battery design, is it makes the production of the actual battery itself a lot simpler. The research was published in the journal Advanced Energy Materials.