In the past, the smallest fuel cells have been two-chambered, but this micro version uses a single chamber with a graphene- rather than platinum-coated carbon cloth anode and an air cathode. Air cathodes have not been used before because if oxygen can get to the bacteria, they can breath oxygen and do not produce electricity.
"We have previously avoided using air cathodes in these systems to avoid oxygen contamination with closely spaced electrodes," said Logan. "However, these micro cells operate at micron distances between the electrodes. We don't fully understand why, but bottom line, they worked."
The anode is actually composed of carbon nanomaterial graphene. Other microbial fuel cells used graphene oxide, but the researchers showed that pure multi-layered graphene can serve as a suitable anode material.
While the researchers tested this mini microbial fuel cell using acetate and human saliva, it can use any liquid with sufficient organic material.
|Contact: A'ndrea Elyse Messer|