Juicing Up Your Cell Phone with Microbial Fuel Cells
Given the sheer amount of toys and gizmos we use on a daily basis, it becomes very easy to take something like a cell phone or MP3 player charger for granted. In poor, developing countries like Uganda, however, even using a charger can be a struggle due to the difficulty inherent in accessing an electrical grid - by some estimates, more than 99% of rural households in the African nation are cut off from a reliable source of electricity.
In an effort to help resolve this long-standing problem, a group of MIT students has devised a microbial fuel cell (MFC) that runs entirely on plant waste. The students' BioVolt MFC prototypes use electrons released by cellulose-munching bacteria to generate electricity. Because the technology has already been around for a few years, the main challenge for the students was to develop a cheap, yet efficient, device - one they tackled in part by making use of a non-platinum catalyst, which allowed them to keep manufacturing costs to a minimum. Though they weren't willing to share the exact specifications for the fuel cell - having decided to file a patent for the device - the students claimed that it could be produced for as little as $2. Used individually, a BioVolt would take about 6 months to completely charge a cell phone's battery (not exactly a practical solution); when connected in series, however, they believe the power output could be increased around 100 fold.