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Instructions are Available Here
 

How does a fuel cell work?:

A fuel cell produces electricity.

Most fuel cells do this using the chemical reaction between hydrogen and oxygen.

Normally hydrogen burns, reacting with oxygen from the air, producing water, heat and light. Sometimes sound is produced too, as in the familiar "pop" test for hydrogen. The reaction is:-

In the fuel cell the chemical reaction is exactly the same, but instead of producing light and heat energy, electrical energy is produced. This is achieved by feeding the hydrogen over one electrode, and the oxygen over another, as in the diagram below. The two electrodes are separated by an electroyte, a material that allows charged molecules or "ions" to move through it.:-

The reaction takes place in the cell, and water is produced. The water is formed in different places depending on what sort of electrolyte is used, but in some cells the water is recovered, and is used for drinking.

To understand how the chemical reaction produces an electric current you need to study it more closely, and this can be done for alkali electrolyte and for acid and "solid polymer" fuel cells at this WWW site. However, at a simple level you could consider it as the reverse of the experiment you might have seen where an electric current is passed through water and it splits up into hydrogen and oxygen. The fuel cell does the opposite, hydrogen and oxygen join together, making water and electricity.

We cannot leave out the fact that fuel cells do not have to use hydrogen as the fuel. The mini fuel cell produced by Electro-Chem-Technic can, for example, run off methanol. The basic chemical reaction is:-

Instead of the heat produced when methanol burns, electrical energy is produced.