Micro fuel cell runs cool

One key to making practical fuel cells for portable devices is finding a design that allows the chemical reaction that extracts energy from fuel to happen at a reasonably cool temperature.

Researchers from the University of California at Los Angeles and Pennsylvania State University have made a tiny methane fuel cell that works at 60 degrees Celsius. They have also shown that the fuel cell can use high concentration methanol to increase its operating time.

The tiny fuel cell could eventually be used in portable and microelectronics devices, according to the researchers.

The fuel cell is relatively simple. It takes in methanol and water on one side and air on the other side of a 750-micron-wide, 400-micron-deep channel bisected by a membrane. A micron is one thousandth of a millimeter. Hydrogen ions diffuse through the membrane, causing electrons to flow. The fuel cell waste products are methanol, water, air and carbon dioxide.

The fuel cell could be used practically in two to five years, according to the researchers. The work appeared in the November 10, 2003 issue of Applied Physics Letters.