There are several types of fuel cells. These are categorized in 5 main parts as below:
- Solid oxide fuel cell (SOFC)
- Alkaline fuel cell (AFC)
- Phosphoric acid fuel cell (PAFC)
- Molten carbonate fuel cell (MCFC)
- Polymer electrolyte fuel cell (PEFC or PEM)
In addition to the above categories, there is one more type named direct methanol fuel cell or DMFC. But this type is commonly included in 5th group. The working temperature of fuel cells can vary between 80 degrees Celsius for PEFCs and 1000 degrees for SOFCs. Low temperature cells have H+ and OH– carriers that exchange ions through electrolyte and electrons through an external circuit. In high temperature cells like MCFCs and SOFCs, electric current is carried by CO32- and o22- .