Monday, 24 April 2017

Efficient microbial fuel cell made from paper


Fuel cells are one of the renewable sources of energy being actively worked on by scientists. The basis of many fuel cells are specific bacteria, and a new breakthrough has been made using a paper-based system.
The search for alternative forms of energy is an important part of technological research. Of the different energy sources being examined, microbial-powered fuel cells are considered one of the most promising clean energy alternatives. A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction. This is the subject of research from the University of Rochester. Not only have scientists made significant progress, they have constructed a fuel cell that relies on bacteria found in wastewater.
One problem limiting fuel cells that use wastewater is corrosion of electrodes. This happens because electrodes have consisted of metal. An alternative type of electrode, made from carbon felt, has also proved limiting because carbon felt is porous and therefore prone to clogging. The solution to this has been to look towards the use of paper; that is a special type of paper coated with carbon paste. The paste is formed from a mixture of graphite and mineral oil.
In terms of how the cell works, the carbon paste attracts electrons emitted by bacteria, of the species Shewanella oneidensis MR-1. This bacterium consumes toxic heavy metal ions in the wastewater and ejects electrons. The electrons are attracted to the carbon coating on the positive electrode (anode), and then proceed to flow to the negative electrode (a platinum cathode), triggering an electrochemical reaction.
In trials the electrode has proved efficient, at twice the density of the carbon-based model. It is also cost-effective and relatively easy to prepare. The research is published in the journal of the American Chemical Society Energy Letters, and it is titled "Extracellular Electron Transfer on Sticky Paper Electrodes: Carbon Paste Paper Anode for Microbial Fuel Cells."
In related news, Digital Journal has reported about a new disposable battery has been developed. The battery remarkably folds like an origami ninja star, and it runs on only a few drops of water.


Posted by Dr. Tim Sandle