Technology

Parts of a Fuel Cell

The anode, which is the negative end of the fuel cell, has several functions. It conducts the electrons that are freed from the hydrogen molecules so that they can be used in an external circuit. It also has channels etched into it that disperse the hydrogen gas equally over the surface of the catalyst.

The cathode, which is the positive end of the fuel cell, has channels etched into it that distribute the oxygen to the surface of the catalyst. It also conducts the electrons back from the external circuit to the catalyst, where they can recombine with the hydrogen ions and oxygen to form water.

The electrolyte is the proton exchange membrane (PEM). It is specially treated material, which resembles plastic wrap that you use in your kitchen, only it conducts positively charged ions. The membrane blocks electrons.

The catalyst is a special material that facilitates the reaction of oxygen and hydrogen. It is made of platinum powder very thinly coated onto carbon paper or cloth. The catalyst is rough so that the maximum surface area of the platinum can be exposed to the hydrogen or oxygen. The platinum-coated side of the catalyst faces the PEM.