All About Fuel Cells  

A fuel cell is very similar to a battery. It produces energy in the form of electricity or heat as long as fuel is supplied, so unlike a battery a fuel cell does not run down or need to be recharged. A fuel cell is made up of an electrolyte surrounded at either end by an electrode. Hydrogen enters the fuel cell by the anode and, and oxygen is sent through the cathode. With the help of a catalyst, hydrogen atoms split into a proton and an electron which then travel separately to the cathode. The electrons create a current which powers the fuel cell, and the protons pass through the electrolyte. The hydrogen protons unite with oxygen molecules and form water. From a fuel cell, water, heat, and electricity are formed. A fuel cell can use any hydrocarbon fuel, and therefore is extremely valuable. Fuel cells are also better for the environment since they rely on a chemical reaction rather than combustion, and so have less harmful by-products.

Types of fuel cells:

Phosphuric Acid: The most commercially developed type of fuel cell, it's already being used in places such as hospitals, nursing homes, hotels, office buildings, power plants, and airports. It ca also be used in larger vehicles such as buses and locomotives. These fuel cells can generate electricity at 40% efficiency, as opposed to 30% efficiency for the most efficient internal combustion engine. This fuel cell operates at about 400 degrees F.

Proton Exchange Membrane: These fuel cells are suited for use in cars as they have relatively low output temperatures of 200 degrees F. PEM cells employ a thin polymer membrane as their electrolyte, and are therefore quite light. They are high-density and could possibly be used in the future for something as small as a video camera.

Molten Carbonate: Offer high fuel-to-electricity ratios and operate at 1,200 degrees F. Further testing is still to be done on them. This type of fuel cell is most likely going to be useful in power plants because of its high temperature output.

Solid Oxide: Promising for use in power plants and in cars as well, this fuel cell has an operating temperature of 1,800 degrees F.

Alkaline: These cells were used by NASA on space missions, and can achieve power efficiencies of 70%. Alkalin Potassium Hydroxide is used as an electrolyte. They have proved to expensive at their current price, but methods of reducing the cost are still being examined.

 A Portable Fuel Cell:

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