Fuel cells are electro-chemical devices that
operate at a high level of efficiency with little
noise or air pollution. There are many potential
applications for fuel cells, including electricity
generation in stationary applications and provision
of motor force for a new generation of transportation
All fuel cells operate on the same principle—they
convert chemical energy directly into electricity
and heat, rather than oxidize (burn) a fuel.
In most, but not all fuel cells, the source
of the fuel’s chemical energy is hydrogen.
In some cases, the fuel may need to be processed,
or “reformed,” before it can be
used in the fuel cell.
An input fuel is catalytically reacted (electrons
removed from the fuel elements) in the fuel
cell to create an electric current. Fuel cells
consist of an electrolyte material that is sandwiched
in between two thin electrodes (porous anode
and cathode). The input fuel passes over the
anode and oxygen passes over the cathode where
it catalytically splits into ions and electrons.
The electrons go through an external circuit
to serve an electric load while the ions move
through the electrolyte toward the oppositely
charged electrode. At the electrode, ions combine
to create by-products, primarily water and CO2.
Depending on the input fuel and electrolyte,
different chemical reactions will occur.