It is very much like a battery that can be recharged while you are drawing power from it. Instead of recharging using electricity, however, a fuel cell uses hydrogen and oxygen. The fuel cell will most likely compete with many other types of energy conversion devices, including the gas turbine in power plants, the gasoline engine, and the battery. Combustion engines like the turbine and the gasoline engine burn fuel and use pressure created by the expansion of the gases to do mechanical work. Batteries store electrical energy by converting it into chemical energy, which can be converted back into electrical energy when needed.
A fuel cell provides a DC voltage that can be used to power motors, lights or any number of electrical appliances. There are several different types of fuel cells , each using a different chemistry. Fuel cells are usually classified by the type of electrolyte they use. Some types of fuel cells show promise for use in power generation plants. Other may be useful for small portable applications or for powering cars. According to www.howstuffworks.com. .
Http://fuelcells.sae.org explains that fuel cells have a very basic design to them. A fuel cell has four basic parts. These parts are the anode, cathode, catalyst, and the proton exchange membrane. The anode, the negative post of the fuel cell, has several jobs. It conducts the electrons that are freed from the hydrogen molecules so that they can be used in an external circuit. It has channels etched into it that disperse the hydrogen gas equally over the surface of the catalyst. .
The cathode, the positive post of the fuel cell, has channel etches also that distribute the oxygen to the surface of the catalyst. Which also conducts the electrons back from the external circuit to the catalyst, where they can recombine with the hydrogen ions and oxygen to form water.
The electrolyte is the proton exchange membrane.