A fuel cell can be defined as an electrochemical device

A fuel cell can be defined as an electrochemical device that uses chemical energy to produce electric power. This process is in the presence of an electrolyte and result into minimal emissions. For the fuel cell to operate continuously the reactants must flow into the cell, and the products out of the cell and the electrolyte must remain within the cell (John & Shahed, 2002).

Although the fuel cell generate power much like the batteries they are different in that they consume reactants from external source which must be replenished while the battery store electric energy chemically