Fuel cells are a special type of electrochemical cell that continuously produces electricity as long as they are supplied with fuel and an oxidising agent. Unlike traditional batteries that store chemical energy internally, fuel cells require a constant supply of fuel from an external source.

One of the most commonly used fuel cells is the hydrogen-oxygen fuel cell. In this cell, hydrogen gas (H₂) reacts with oxygen gas (O₂) to produce water (H₂O), generating electricity in the process.

How Hydrogen-Oxygen Fuel Cells Work The overall chemical reaction in a hydrogen-oxygen fuel cell is:

This reaction can be broken down into two redox half-equations that occur at the anode and cathode of the fuel cell:

1. Anode Reaction (Oxidation):

• Hydrogen gas (H₂) is fed into the fuel cell at the anode.
• The hydrogen molecules are oxidised, losing electrons and forming hydrogen ions (H⁺):

• The electrons released travel through an external circuit, creating an electric current that can be used to power devices.

2. Cathode Reaction (Reduction):

• Oxygen gas (O₂) is introduced at the cathode.
• The oxygen molecules gain the electrons coming from the external circuit and react with the hydrogen ions (H⁺) to form water:

These reactions occur simultaneously, with the electrons flowing from the anode to the cathode through the external circuit, and the ions moving through the electrolyte within the cell.