Basic cathode-electrolyte-anode construction of a fuel cell

Electrode structure is porous. As a result both the electrolyte form one side and the gas from the other side can penetrate it. Thus there occurs maximum possible contact between the electrode, the electrolyte and the gas. 

The hydrogen gas ionizes at the anode of an electrolyte. There can be released electrons, ions and energy. 

Oxygen reacts with electrons taken from the electrode and ions from the electrolyte in order to form water. 

Three main ways for dealing with the slow reaction are to use catalysts, to raise the temperature and to increase the electrode area. Using catalysts and raising the temperature can be applied to any chemical reaction. However, increasing the electrode area is special to fuel cells and it s very important. Electrode area is such an important issue that the performance of a fuel cell design is often quoted in terms of the current per centimeter square. 

The surface area of an electrode is much different than multiplication of its length and width. The electrode is made highly porous. This property increases the effective surface area. Modem fuel cell electrodes have a microstmcture which gives them surface areas that can be hundreds of times their straightforward length x width . Thus, the micro-stmctural design and manufacture of a fuel cell electrode is very important subject for fuel cells [10]. 

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Figure n.5. Basic cathode-electrolyte-anode construction of a fuel cell... 

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