Fuel Cells
What is a fuel cell?
A fuel cell is a device that generates electricity by a chemical reaction. Every fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode. The reactions that produce electricity take place at the electrodes.
Every fuel cell also has an electrolyte, which carries electrically charged particles from one electrode to the other, and a catalyst, which speeds the reactions at the electrodes.
Hydrogen is the basic fuel, but fuel cells also require oxygen. One great appeal of fuel cells is that they generate electricity with very little pollution-much of the hydrogen and oxygen used in generating electricity ultimately ...
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electricity behaves, this current returns to the fuel cell, completing an electrical circuit. The chemical reactions that produce this current are the key to how a fuel cell works.
There are several kinds of fuel cells, and each operates a bit differently. But in general terms, hydrogen atoms enter a fuel cell at the anode where a chemical reaction strips them of their electrons. The hydrogen atoms are now "ionized," and carry a positive electrical charge. The negatively charged electrons provide the current through wires to do work. If alternating current (AC) is needed, the DC output of the fuel cell must be routed through a conversion device called an inverter.
Oxygen enters the fuel cell at the cathode and, in some cell types (like the one illustrated above), it there combines with electrons returning from the electrical circuit and hydrogen ions that have traveled through the electrolyte from the anode. In other cell types the oxygen picks up electrons and then travels ...
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by the choice of electrolyte. The design of electrodes, for example, and the materials used to make them depend on the electrolyte. Today, the main electrolyte types are alkali, molten carbonate, phosphoric acid, proton exchange membrane (PEM) and solid oxide. The first three are liquid electrolytes; the last two are solids.
The type of fuel also depends on the electrolyte. Some cells need pure hydrogen, and therefore demand extra equipment such as a "reformer" to purify the fuel. Other cells can tolerate some impurities, but might need higher temperatures to run efficiently. Liquid electrolytes circulate in some cells, which requires pumps. The type of electrolyte also dictates a ...
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Fuel Cells. (2014, February 21). Retrieved November 23, 2024, from http://www.essayworld.com/essays/Fuel-Cells/103712
"Fuel Cells." Essayworld.com. Essayworld.com, 21 Feb. 2014. Web. 23 Nov. 2024. <http://www.essayworld.com/essays/Fuel-Cells/103712>
"Fuel Cells." Essayworld.com. February 21, 2014. Accessed November 23, 2024. http://www.essayworld.com/essays/Fuel-Cells/103712.
"Fuel Cells." Essayworld.com. February 21, 2014. Accessed November 23, 2024. http://www.essayworld.com/essays/Fuel-Cells/103712.
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