|a cell in which the energy produced by oxidation of a fuel is converted directly into electrical energy|
|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
|a stew of meat, vegetables, potatoes, etc.|
A device that produces electricity by combining a fuel, usually hydrogen, with oxygen. In this reaction, electrons are freed from the hydrogen in the fuel cell by a catalyst, and gain energy from the chemical reaction binding hydrogen and oxygen; this provides a source for electric current. The exhaust of hydrogen fuel cells consists simply of water. Fuel cells are currently used in spacecraft, and increasingly in ground transportation, with potential use everywhere electricity is required.
An electrochemical device where a chemical reaction produces energy that is converted directly into electricity. Once used primarily in space travel, fuel cells are now being considered for use in cars. Unlike internal-combustion engines, fuel cells do not pollute the environment.