Operation of a single chamber MFC is complicated by oxygen poisoning resulting from the conflicting requirements of the anaerobic population and the cathode requirement for dissolved O2. This design attempts to limit oxygen poisoning by using a brush type carbon electrode combined conventional carbon paper to provide a gas barrier without limiting free flow of the microbial medium.
The use of styrofoam as the permeable membrane is novel as far as I can tell.
Conductive cloth is used to provide an inexpensive silver catalyst to promote oxidation at the cathode. We use silver plated conductive cloth from lesseremf but any silver plated material should do. The use of silver as a catalyst is based on the research done for the air cathode in an aluminum air battery and is experimental in an MFC.
As you can see from the picture I got about 90 mV across the open circuit after charging and assembling the cell. The extraction of power from an MFC scales directly in proportion to two things, population density and surface area of the electrode surface at the cathode and anode.
Power will continue to rise as the population density increases.
Step 1: Bill of Materials
1 5 gallon plastic pail with lid - I got my mine at Home Depot on sale for $2.97 plus the lid
8 in styrofoam disc - Cut out of packing material or I'm using one I got at Michael's
Use loose styrofoam if you can get it. You want air to pass easily through
Anaerobic Microbial Culture - I'm using "Microbe Lift" brand Septic Tank and Cesspool Treatment
Yeast should also work
1 Package of large aquarium charcoal filter pads. I'm using Fluval brand 4 PLUS filters
Silver coated conductive cloth - http://www.lessemf.com/fabric.html I'm using the "Stretchy silver coated sheer nylon weave". This is used as a catalyst to facilitate oxyidation at the air cathode. It also as the electron collection grid.
A couple of wire leads with clips or some way to attach them to the carbon pads.
Two sheets of carbon paper. This is used to get good mechanical connectivity between the pads.