Interface Engineering Between Membrane and Electrodeposited-IrO2 Electrode Using One-Sided Hot Pressing to Produce Efficient Proton Exchange Membrane Water Electrolyzers

Abstract

Designing the structure of a membrane electrolyte assembly (MEA) is essential to maximizing catalyst utilization and improving the electrode performance at the single-cell level. In this study, one-sided hot pressing was employed to enhance catalyst utilization in an electrodeposited IrO2 electrode for use in proton exchange membrane water electrolyzer (PEMWE) systems. An oxygen electrode loaded with 0.13 mgIr cm(-2) IrO2 was prepared via the anodic electrodeposition onto a Ti porous transport layer (PTL), which was subsequently assembled with a Nafion membrane via one-sided hot pressing. The IrO2/Ti-PTL electrode penetrated the membrane, and its pores were partially filled with the membrane component. The mean vertical thickness of the zone in which the IrO2/Ti-PTL pores are filled with the membrane strongly affected the contact area between the electrode and electrolyte, with greater thickness resulting in a broader electrode/electrolyte interface but reduced reactant (H2O) accessibility. The cell current density at 1.7 V and 80 degrees C was significantly improved to 1.44 A cm(-2) using the one-sided hot pressing approach; these were comparable to the values reported for state-of-the-art particle-type electrodes bearing higher loadings of platinum group metal (PGM) catalysts (similar to 0.5 mg). This work highlights the great potential of film-type electrodes for use as low-PGM oxygen electrodes in PEMWEs.