Polymer Exchange Membrane Fuel Cells

#The polymer exchange membrane fuel cell (PEMFC) is one of the most promising fuel cell technologies. This type of fuel cell will probably end up powering cars, buses and maybe even your house. PEMFC  use hydrogen fuel and oxygen from the air to produce electricity.


Fuel Cell Chemistry:
A proton exchange membrane fuel cell transforms the chemical energy liberated during the electrochemical reaction of hydrogen and oxygen to electrical energy, as opposed to the direct combustion of hydrogen and oxygen gases to produce thermal energy.

A stream of hydrogen is delivered to the anode side of the membrane electrode assembly (MEA). At the anode side it is catalytically split into protons and electrons. This oxidation half-cell reaction is represented by:
At the Anode:

 2H2----->4H+ + 4e-    Eo = 0V

The newly formed protons permeate through the polymer electrolyte membrane to the cathode side. The electrons travel along an external load circuit to the cathode side of the MEA, thus creating the current output of the fuel cell. Meanwhile, a stream of oxygen is delivered to the cathode side of the MEA. At the cathode side oxygen molecules react with the protons permeating through the polymer electrolyte membrane and the electrons arriving through the external circuit to form water molecules. This reduction half-cell reaction is represented by:


At the Cathode:

   O2 + 4H+ + 4e-  -----> 2H2O   Eo = 1.229V




Overall reaction:
Overall: 2H2 + O2------->2H2O + energy

 Eo = 1.229V