The Effect of Ion Exchange Poisoning on the Ion Transport and Conduction in Polymer Electrolyte Membranes (PEMs) for Water Electrolysis

In water electrolyzers, polymer electrolyte membranes (PEMs) such as Nafion can accumulate cations stemming from salt impurities in the supply, which leads to severe cell voltage increases. This combined experimental and computational study discusses influence of sodium ion poisoning on ionic conductivity transport a thereon based electrolysis cell. Conductivities aqueous solutions with same amount dissolved are measured impedance spectroscopy compared respect Nafion’s microstructure. The dynamic behavior is characterized function content current density, showing differences at alternating direct currents. These results elucidated physical model for poisoned membranes, describes proton depletion accumulation cathode. During depletion, cathodic hydrogen evolution maintained by reduction that forms hydroxide ions. Together ions membrane, formed diffuse pairwise into so membrane’s be least partly replaced anodically protons.