Estimating the energy requirement for hydrogen production in proton exchange membrane electrolysis cells using rapid operando hydrogen crossover analysis

Hydrogen (H2) crossover in proton exchange membrane water electrolyzers refers to the process by which hydrogen produced at the cathode traverses the membrane and mixes with the oxygen produced at the anode. This phenomenon reduces efficiency and may pose flammability hazards. In this work we present a method for quantifying the H2 content of the anode exhaust gas using a gas chromatograph that is capable of sampling data every 2 min. Subsequent theory is presented to calculate the crossover flux, overall H2 efficiency, and H2 energy requirements. Results the effects of membrane thickness using Nafion™ N117 (178 μm) and Nafion™ NR212 (51 μm) membranes. It was found that thinner membranes lead to improved VI performance but exhibit higher crossover rates. Despite their increased crossover, leading to decreased hydrogen efficiency, the calculated required energy for NR212 membrane-electrode assemblies (MEAs) was significantly lower than that of N117 MEAs.