A fuel cell is an electrochemical energy converter—it converts chemical energy of fuel, typically hydrogen, directly into electrical energy. As such, it must obey the laws of thermodynamics.
The electrochemical reactions in fuel cells happen simultaneously on both sides of the membrane—the anode and the cathode. The basic fuel cell reactions are as follows:
At the anode:
At the cathode:
These reactions may have several intermediate steps, and there ...