1 - Proton exchange membrane fuel cells

Abstract

When oil, one of the most important energy sources in the history of mankind, was first discovered in Pennsylvania almost 150 years ago, the fuel cell had already been known for 20 years, invented by Sir William Grove, “father of the fuel cell,” in 1839. Back then it was an idea that was far ahead of its time. Today, however, it is the most important development in the history of decentralized energy supply. Today, fuel cells are widely considered to be efficient and nonpolluting power sources offering much higher energy densities and energy efficiencies than any other current energy storage devices. Fuel cells are, therefore, considered to be promising energy devices for the transport, mobile, and stationary sectors. A fuel cell is an “electrochemical” device operating at various temperatures (up to 1000°C) that transforms the chemical energy of a fuel (hydrogen, methanol, natural gas, etc.) and an oxidant (air or pure oxygen) in the presence of a catalyst into water, heat, and electricity. Furthermore, the power generated by a fuel cell depends largely upon the catalytic electrodes and materials used. There are currently six main groupings of fuel cell available: (i) proton exchange membrane fuel cell (PEMFC) including direct methanol fuel cell; (ii) alkaline fuel cell (AFC); (iii) phosphoric acid fuel cell (PAFC); (iv) molten carbonate fuel cell (MCFC); (v) solid oxide fuel cell (SOFC); and (vi) microbial fuel cell (MFC). PEMFC, AFC, PAFC, and MFC operate at low temperatures in the range of 50–200°C and MCFC and SOFC at high temperatures in the range of 650–1000°C. This chapter focuses on the proton exchange membrane fuel cell (PEMFC).