PEM Fuel Cell
One of the more common types of fuel cell is the Polymer Electrolyte Membrane (PEM) fuel cell. The PEM fuel cell consists of an electrolyte membrane sandwiched between an anode (negative electrode) and a cathode (positive electrode).
next
PEM:
The PEM is a thin, solid, organic compound, typically the consistency of plastic wrap and about as thick as 2 to 7 sheets of paper. This membrane functions as an electrolyte: a substance that conducts charged ions (in this case protons), but does not conduct electrons. This allows the solution to conduct electricity. This membrane must be kept moist to conduct particles through it.
next | top
Anode:
The anode is the electrode at which oxidation (loss of electrons) takes place. In a fuel cell, the anode is electrically negative. The anode is composed of platinum particles uniformly supported on carbon particles. The platinum acts as a catalyst, increasing the rate of the oxidation process. The anode is porous so that hydrogen can pass through it.
next | top
Cathode:
The cathode is the electrode at which reduction (gaining of electrons) takes place. In a fuel cell, the cathode is electrically positive. The cathode is composed of platinum particles uniformly supported on carbon particles. The platinum acts as a catalyst, increasing the rate of the reduction process. The cathode is porous so that oxygen can pass through it.
next | top
Flow Plates:
Flow plates perform several important functions:
- they channel hydrogen and oxygen to the electrodes,
- they channel water and heat away from the fuel cell, and
- they conduct electrons from the anode to the electrical circuit and from the circuit back to the cathode.
top |
