Villi-shaped electrode lifts output of spore-fed microbial fuel cell

Binghamton researchers copied the gut's finger-like villi to get 8.3 times the power density from a bacterial fuel cell, in lab tests only.

Researchers at Binghamton University have built a bacteria-powered biobattery whose anode copies the villi lining the small intestine. Under volume-matched conditions it produced 66.45 µW/cm³, against 8.04 µW/cm³ for a flat electrode. That is an 8.3-fold gain. The work was published in the journal Small, from the Bioelectronics and Microsystems Lab led by Prof. Seokheun Choi.

The device is a microbial fuel cell, which uses living microbes to turn the chemical energy in organic matter into electricity. The anode is a set of finger-like pillars coated in a hydrogel of polyvinyl alcohol, the conductive polymer PEDOT and reduced graphene oxide. Dormant Bacillus subtilis spores sit inside these artificial villi and germinate when a nutrient solution is added. That liquid also serves as the electrolyte. A modified carbon-cloth cathode is separated from the anode by an ion-exchange membrane. The team made and tested 24 configurations with different pillar heights and radii. They also built flexible multi-villi patches and tested them in a simulated wastewater-pipe environment.

The gain matters because low output is part of why microbial fuel cells are still mostly confined to research, pilots and specialized uses. Earlier porous electrodes tended to clog as biofilms formed, which blocked nutrient delivery and trapped waste. Raising output per unit volume without that problem makes small, biodegradable power sources for disposable sensors more plausible. Such sources would avoid toxic materials, and that would lower the cost of monitoring things like water and pipes.

Treat it as early. The numbers come from lab conditions, including a simulated pipe, not real deployments. The comparison is against a flat electrode of matched volume, not against other battery types. The source text was cut off after the headline result, so later details are missing. Grid-scale impact is not near. Watch for tests in real wastewater and for data on how long the cells keep running.

Source: New Atlas