Evaluating Cation-Exchange Membrane Properties Affecting Polymer Electrolyte Membrane Water Electrolysis.

Ion-exchange membranes are crucial components in water electrolysis using polymer electrolyte membrane water electrolysis (PEMWE) for green hydrogen production. However, the impact of membrane properties on the device performance has not been adequately studied, and the extent to which easily implementable strategies can improve the membrane properties remains unclear. This study investigates simple yet practical strategies to change PEMWE performance by examining how the ion-exchange capacity of cation exchange membranes and the pretreatment (e.g., water and acid wash) of catalyst-coated membranes influence device-level performance, moving beyond the traditional focus on catalysts and cell assembly. Our results show that increasing the ion-exchange capacity not only decreases the series resistance but also improves the charge transfer at the electrochemical reaction interface. Enhancing the membrane properties alone can boost the current-voltage characteristics of PEMWE without altering the catalysts.