Alkaline Fuel Cell Systems are being developed and manufactured by a number of companies worldwide. Opportunities to form partnerships with companies developing alkaline fuel cell technology can be accessed here.
Alkaline fuel cells (AFC’s) have an alkaline electrolyte - commonly a liquid such as Potassium Hydroxide (KOH). In an AFC, hydroxide ions (OH-) travel from cathode to anode. This differentiates them from PEM Fuel Cells which have a solid polymer electrolyte which conducts protons.
Characteristics of alkaline fuel cells include:
Required Fuel: Pure Hydrogen
Operating Temperature: There are both low temperature and high temperature AFC’s. Low temperature AFC’s operate at temperatures as low as 25°C up to 75°C. High temperature AFC’s operate at 100°C up to 250°C.
Power density: Lower than PEM Fuel Cells
Efficiency: Theoretical efficiency of Alkaline fuel cells is better than that of PEM. A typical Alkaline fuel cell will have an electrical efficiency of ~50%, though 60% has been achieved by UTC Power, who supply Alkaline fuel cells to NASA’s Space Shuttle Fleet.
Applications: Stationary Power, and Portable Generators
Commercial viability: Although there are many fewer Companies Developing AFC Technology, when compared to Companies Developing PEM Technology, the possibility to use less expensive materials, such as non-platinum catalysts makes them a commercially attractive technology option.
Additional Information: AFCs were used on Apollo space missions to provide electricity for the on-board needs of the shuttle. In addition to this, the major advantage of AFCs is that pure hot water is produced as the ‘waste’ product. Therefore, on the shuttle in addition to providing electricity the AFCs provided Heat, Cooling, Hot water, and ultimately – drinking water for the astronauts!
Chemical Equations:
Anode Reaction: 2H2 + 4OH- »» 4H2O + 4e-
Cathode Reaction: O2 + 2H2O + 4e- »» 4OH-
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