A micro fuel cell is a power source for electronic devices that converts chemical energy into electrical energy. Fuel cells operate by oxidizing combustible fuel, such as hydrogen or alcohol. These energy sources, on a large scale, have been deployed in motor vehicles. Most of these devices use hydrogen. Recently, scaled-down fuel cells have been developed for use with devices such as digital cameras, portable radios, and notebook computers. These devices use fuels other than hydrogen, most notably methanol, a form of alcohol. Fuel cells differ from conventional electrochemical cells and batteries. Both technologies involve the conversion of potential chemical energy into electricity. But while a conventional cell or battery employs reactions among metals and electrolytes whose chemical nature changes over time, the fuel cell actually consumes its fuel, leaving nothing but an empty reservoir or cartridge. A common example of conventional electrochemical technology is the lead-acid automotive battery. Another is the lithium-ion battery. Some conventional cells and batteries can be recharged by connection to an external source of current. Others must be discarded when they are spent. A fuel cell, in contrast, is replenished merely be refilling its reservoir, or by removing the spent fuel cartridge and replacing it with a fresh one. While the recharging process for a conventional cell or battery can take hours, replacing a fuel cartridge takes only seconds. The worldwide market for micro fuel cells is expected to increase in the next several years as technologies improve and costs come down