The fuel cell is an electrochemical system that directly transforms the energy contained in a hydrogen molecule into electricity.
Fuel cells use H2 (hydrogen) and O2 (oxygen) to generate electricity and heat, emitting only water. The H2 molecule is composed of 2 atoms, each of which contains a positive nucleus, called a proton or H+, and an electron.
Regarding the PEM technology (Proton Exchange Membrane), the electrochemical system contains a membrane inserted between two metallic conduction plates. This polymer membrane only lets H+ protons, the nucleus of hydrogen atoms, pass through.
The hydrogen molecule comes into contact with the electrodes. The reaction is triggered by a catalyst, which is composed of nanoparticles of platinum coated on carbon particles. When the hydrogen comes into contact with the platinum, the hydrogen molecule gives birth to two protons and two electrons.
The protons pass through the membrane and move toward the other side of the cell. The electrons, which cannot pass through this barrier, pass into the electrical circuit. Simultaneously, on the other side of the membrane in contact with a new catalyst, the protons react with the oxygen and the electrons of the circuit, to form water, the fuel cell’s only by-product.