Though, it wasn't until 1932 that the first successful cell device was built from inventions of engineer Francis Bacon.
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Since the first successful fuel cell, a number of different types of fuel cells have been invented. They are usually classified by the type of electrolyte which they use. An alkaline fuel cell (AFC) is one of the oldest designs. It is highly susceptible to contamination; therefore, it requires pure hydrogen and oxygen to be used. This results in it being very expensive and unlikely to be commercialized; although, it has been used in the United States space program since the 1960's. Another type is the phosphoric-acid fuel cell (PAFC). It operates at a higher temperature than the PEM fuel cell (which will be discussed shortly), giving it a longer warm-up time and unsuitable for use in automobiles. It does, however, have potential for use in small, stationary power-generation systems. Yet another type of fuel cell is the solid oxide fuel cell (SOFC). This fuel cell operates at very high temperatures of around 1832 degrees F or 1000 degrees C creating reliability problems. However, this high temperature does have one large benefit. The steam produced by the fuel cell can be channeled into turbines to generate more electricity which improves the overall efficiency of the fuel cell. This is best suited for use at large-scale, stationary power generators that could provide electricity for factories or towns. A similar fuel cell is the molten carbonate fuel cell (MCFC) which operates at 1112 degrees F or 600 degrees C. Like the SOFC, this fuel cell also produces steam that can be used to generate more electricity and improve the overall efficiency. It is best suited for large, stationary power generators. The final type of fuel cell is the proton exchange membrane fuel cell (PEMFC). Though it uses one of the simplest reactions of any fuel cell, it is the most promising.
