Influence of Contact Pressure on Hydrogen Crossover and Polarization Behavior in AEM Water Electrolysis

Anion exchange membrane water electrolysis (AEMWE) holds the potential to become a key technology for future hydrogen production. In the present study, the influence of contact pressure on hydrogen crossover and polarization behavior is systematically investigated in a range from 0.5 MPa to 2.5 MPa in 0.5 MPa increments. The electrodes were prepared as catalyst-coated substrate (CCS), applying 3 mg cm-2 NiFe2O4 on the anode substrate and 0.5 mg cm-2 Pt on the cathode substrate. It is demonstrated that an elevated contact pressure results in a decreased high frequency resistance (RHF), while simultaneously leading to a significantly increased hydrogen content on the anode side. At 3 A cm-2 the ohmic resistance decreases by approx. 30 m Omega cm2 when increasing the contact pressure from 0.5 MPa to 2.5 MPa, whereas the anodic hydrogen content increased by approx. 1.5 vol.% respectively. Additionally, it can be observed that the selection of the gas diffusion layer (GDL) material has a strong effect on hydrogen crossover, while the influence on cell voltage is insignificant. Overall, these results show a promising starting point for further investigations on the interactions between cathode properties, cell compression and anodic gas contamination.