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  Fuelcell: Alkaline Fuel Cells (AFC)
 

Introduction l

Direct Methanol l

Alkaline l

Proton Exchange Memb. l

Solid Oxide l

Molten Carbonate l

Phosphoric Acid l

   

 

 

Alkaline fuel cells use a solution of potassium hydroxide in water as their electrolyte: this makes them sensitive not to CO as the PEMFC is, but to CO2, meaning that oxygen has traditionally been used as the oxidant in the system. This has led to few uses outside aerospace, although some of the first experimental vehicles were powered by AFCs. They use comparatively cheap materials in their electrodes but are not as power dense as PEMFCs, making them bulky in some situations. AFCs could be used for generating up to 200 kW and operating temperatures range from 60 to 90°C.

The AFC, like the PEMFC, is happiest when fed pure hydrogen, so the issue of refueling must be addressed if these vehicles are going to progress in the marketplace.

The alkaline fuel cell has been used with great success in the past in space missions, dating back to the Apollo and Gemini missions in the 1960s. It is still in use in the Space Shuttle today and provides not only the power but also the drinking water for the astronauts.

Some commercial attempts have been made to introduce AFCs in other markets. Most notably, in the late 90s, Zero Emission Vehicle Company (ZEVCO) launched its prototype London taxi based on the technology; the project however was not successful and subsequently abandoned.

Currently AFCs do not appear to be widely considered as viable options, and their use is restricted to space vehicles only.

For further information contact David Hart (email: firstname.lastname@e4tech.com) from E4tech

 

 
 
 
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