ABSTRACT
As we have discussed in Chapter 1, a number of different fuel cells have been under development and are in use for a wide range of applications. These fuel cells are generally classified by the type of electrolyte used, type of ion transferred, and the range of applicable temperature level. The most commonly used fuel cells are alkaline fuel cell (AFC), phosphoric acid fuel cell (PAFC), polymer electrolyte membrane fuel cell (PEMFC), molten carbonate fuel cell (MCFC), and solid oxide fuel cell (SOFC). Among these, PAFC and PEMFC are referred to as cation fuel cells with positively charged proton (H+) as transporting ion. Fuel cells such as AFC, MCFC, and SOFC are termed anion fuel cells, which involve negatively charged ions transporting through the electrolytes such as hydroxyl ion (OH-), carbonate ion CO3
2−( ), and oxide ion (O2-), respectively. In this chapter, descriptions of these fuel cells are given with regard to the design, major components, materials, operation, and technical challenges.
