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 the anode and cathode, respectively. The reactions that produce
electricity take place at the electrodes.
How do fuel cells work?
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 an alternating current (AC) is needed, the DC output of
the fuel cell must be routed through a conversion device called an inverter.
Graphic by Marc Marshall, Schatz Energy Research Center
Oxygen enters the fuel cell at the cathode and, in some cell types (like the one illustrated above), it
combines there 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 through the electrolyte to the anode, where it combines with hydrogen ions.
The electrolyte plays a key role. It must permit only the appropriate ions to pass between the anode and
cathode. If free electrons or other substances could travel through the electrolyte, they would disrupt the
chemical reaction.
Whether they combine at anode or cathode, together hydrogen and oxygen form water, which drains
from the cell. As long as a fuel cell is supplied with hydrogen and oxygen, it will generate electricity.
What Is the difference between the battery and the fuel cell?
A fuel cell is similar to a battery in that an electro-chemical reaction is used to create electric current. The
charge carriers can be released through an external circuit via wire connections to anode and cathode
plates of the battery or the fuel cell. The major difference between fuel cells and batteries is that batteries
carry a limited supply of fuel internally as an electrolytic solution and solid materials (such as the lead acid
battery that contains sulfuric acid and lead plates) or as solid dry reactants (such as the zinc carbon
powders found in a flashlight battery). Fuel cells have similar reactions; however, the reactants are gases
(hydrogen and oxygen) that are combined in a catalytic process. Since the gas reactants can be fed into
the fuel cell and constantly replenished, the unit will never run down like a battery
Fuel Cell advantages

High efficiency conversion:Fuel cells convert chemical energy directly into electricity without
the combustion process. As a result, a fuel cell is not governed by thermodynamic laws, such
as the Carnot efficiency associated with heat engines, currently used for power generation.
Fuel cells can achieve high efficiencies in energy conversion terms, especially where the waste
heat from the cell is utilized in cogeneration situation.

High power density: A high power density allows fuel cells to be a relatively compact source
of electric power, beneficial in application with space constraints. In a fuel cell system, the fuel
cell itself is nearly dwarfed by other components of the system such as the fuel reformer and
power inverter

Quiet operation: Fuel cells, due to their nature of operation, are extremely quiet in operation.
This allows fuel cells to be used in residential or built-up areas where the noise pollution is
undesirable.
Fuel Cell Disadvantage
High costs compared to other energy systems technology.