Mass Transport Limitations in Proton Exchange Membrane Fuel Cells and Electrolyzers

The performance of Proton Exchange Membrane Fuel Cells (PEMFC) and Electrolyzers (PEME) is subject to mass transport limitations. Within this chapter we will discuss the origination of those limitations and the current research efforts for mitigation. Hydrogen powered fuel cells operate based on the reaction of hydrogen and oxygen, (Figure 1) where the anode reaction is found in Eq. 1, the cathode reaction in Eq. 2 and the overall reaction in Eq. 3. The reverse of this reaction (Eq. 4) is electrolysis. Where, in the electrolyzer the anode reaction is Eq. 5 and the cathode reaction is Eq. 6.