A fuel cell can be referred to as an electrochemical energy conversion device. It works towards producing electricity from varied external quantities of fuel as well as oxidant. These also tend to react in the presence of an electrolyte. Usually, the reactants flow inwards and reaction products flow outwards. The electrolyte is seated inside the cell. Fuel cell can operate consistently in case; all the requisite flows are maintained properly.
Fuel cells are quite different from batteries in reference to their consumption of reactant that needs to be replenished when batteries store electrical energy in a closed system chemically. The electrodes seated inside a battery tend to react as well as change with the charge or discharge of a battery. Here, the electrodes of fuel cell are catalytic and stable.