fuel cell

Definition

Device that converts chemical energy of a fuel (usually hydrogen) directly into electrical energy. In this process hydrogen is continuously passed over a porous nickel or platinum alloy cathode that splits the hydrogen into electrons and protons. The electrons pass through an external circuit whereas the protons (after passing through a liquid or membrane electrolyte) travel to a porous carbon anode over which oxygen is continuously passed to yield water. The efficiency of fuel cells (80 percent) is well over twice that of other such devices, but they are bulky and require constant supply of gases. Their main use is in spacecraft and submarines, and the possibility of using them in cars is being explored. Invented in 1854 by the UK physicist William Robert Grove (1811-1896).