Fuel Cells and the Challenges Ahead

A fuel cell is an energy conversion device that electrochemically converts chemical energy held within two reactants, a fuel and an oxidant, into electrical energy. Fuel can be any ordinary fuel, but hydrogen is most commonly used. The oxidant is most commonly oxygen, usually in the form of ambient air. This chapter briefly explains the difference between a fuel cell and a battery, the components of a fuel cell, its inner workings and processes, and basic performance-cost trade-offs. This chapter also describes the fuel cell as part of an integrated system and its balance of plant (BoP) constituents. Finally, the chapter discusses major types of fuel cells, including proton exchange membrane fuel cells (PEMFCs) or polymer electrolyte fuel cells (PEFCs), direct methanol fuel cells (DMFCs), alkaline fuel cells (AFCs), phosphoric acid fuel cells (PAFCs), molten carbonate fuel cells (MCFCs), and solid oxide fuel cells (SOFCs).