Fuel Cells

Fuell Cells

A fuel cell is an 'electrochemical energy conversion device' used to produce electricity. To do this, most fuel cells convert the gases hydrogen and oxygen into water, a process which produces electricity. Unlike other electrochemical devices (like batteries for example), fuel cells will constantly produce electricity as long as there is a flow of chemicals into the cell. Fuel cells produce electricity in a direct current which can be used to power motors, lights or any electrical appliance. Fuel cells are likely to become the main power source for houses and cars in the near future.

The oxygen used by fuel cells comes from the open air, however hydrogen is much harder to store. A reformer is used to convert hydrocarbons or alcohols into hydrogen which can then be used in the fuel cell. This process however produces other, less useful gases which lower the efficiency of the process. Some of the best fuels for producing hydrogen are natural gas, methanol and propane. Natural gas and propane pipe lines already flow to most houses so these will most probably be the fuels used for home fuel cells. Methanol is easy to transport and has similar properties to gasoline so will most likely be used to power the fuel cells in many vehicles.

Fuel cells work on a very simple electrochemical reaction in which oxygen continuously passes over the cathode and hydrogen over than anode to generate electricity. Since there are no moving parts, it's a quiet and reliable way to produce electricity.

The electrolyte which separates the anode and the cathode is made of a material which conducts ions. The process in which electricity is produced in a fuel cell is: at the anode, hydrogens electrons are separated from the atom so that the hydrogens protons pass through the electrolyte while the electrons pass through an external electrical circuit. It is this which is used to power electrical devices as it comes through in a direct current. The hydrogens protons combine with the oxygen at the cathode and are recombined with the electrons to form water. The reactions are shown below.

Anode Reaction: 2H2 => 4H+ + 4e-

Cathode Reaction: O2 + 4H+ + 4e- => 2H2O

Overall