The function of the PEM fuel cell in seven steps (see animation):

Step 1

Inside the two seperate gas supply cicuits the gaseous oxygene and hydrogen flow into the gas area and the catalyzer.

Step 2

While getting in contact with the catalyzer the hydrogen molecules (H2) are splitted into two H+ protons. At the same time each hydrogen atom sends out one electron.

Step 3

The protons move through the electrolyte (membrane) to the cathode area.

Step 4

The electrons move from the anode to the cathode and cause an electric current. This electric current supplies an electric capacitor with electric power.

Step 5

Respectively four electrons recombine with one hydrogen molecule at the cathode.

Step 6

The now generated oxygene ions have a negative load. They move to the positiv loaded protons.

Step 7

The oxygene ions give their electrons to the two protons and oxidize to water.