ÐÇ¿Õ´«Ã½

Read our policy.

Close menu
Table 1: Fuel cell types
Cell type Electrolyte Operating temperature Efficiency Output Applications Disadvantages
Alkali (AFC) Generally potassium hydroxide in water 150 – 200°C 70% 300 W – 5 kW Used on Apollo spacecraft to provide electricity and drinking water and in prototype taxi by ZEVCO in London. Require pure hydrogen fuel; platinum electrodes are expensive, although companies are examining ways of reducing costs; can leak.
Molten carbonate (MCFC) High temperature compounds of salt carbonates 650°°ä 60 – 80% Up to 2 MW with 100 MW units designed Creation of waste heat to make steam for heating, industrial processing or in steam turbines to generate more electricity. High temperature limits materials and safe use of MCFCs – too hot for home use. Also, carbon dioxide needs to be injected to compensate for carbonate ions used in reactions.
Phosphoric acid (PAFC) Phosphoric acid 150 – 200°C 40 – 80% Existing cells up to 200 kW; 11 MW units have been tested Used in public transport, but limited applications in private cars as warm-up time needed. Have been used in stationary power generation. Platinum electrode catalysts are needed and internal parts must be able to withstand acid.
Proton exchange membrane (PEM) Polymer electrolyte in thin permeable sheet 80°°ä 40 – 50% 50 – 250 kW Operate at low enough temperatures to be suitable for homes and cars. Fuels must be purified; platinum catalyst used raises costs.
Solid oxide (SOFC) Hard ceramic compound of metal oxides 1000°°ä 60% Up to 100 kW Most common use is in large stationary power plants. High temperature limits applications and electrolytes can crack.