Versatile Decal-Transfer Method for Fabricating and Analyzing Microporous Layers in Polymer Electrolyte Membrane...

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Polymer electrolyte membrane water electrolysis (PEMWE) relies on costly iridium catalysts.
• Enhanced catalyst utilization is crucial for reducing iridium loading and improving PEMWE economics.
• Microporous layers (MPLs) are increasingly important for optimizing the interface between porous transport layers (PTLs) and catalyst layers (CLs).

Purpose of the Study:

• To develop standardized methods for MPL design and fabrication for PEMWE.
• To investigate the impact of MPL properties on two-phase transport phenomena at the CL/PTL interface.
• To establish guidelines for optimal MPL design to enhance catalyst utilization and reduce overpotentials in PEMWE.

Main Methods:

• A decal-transfer method was employed to fabricate uniform, thin MPLs at the CL/PTL interface.
• MPL properties, including pore size, thickness, and back-layer structure, were systematically varied.
• Two-phase transport phenomena were investigated under varying MPL conditions to assess their effect on PEMWE performance.

Main Results:

• Smaller micrometer-scale pores in MPLs were found to significantly enhance catalyst utilization.
• Optimized MPLs strengthened water capillary forces, leading to reduced kinetic and transport overpotentials.
• The influence of the MPL back-layer structure on performance was minimal, provided it did not impede in-plane mass transport.

Conclusions:

• The CL/PTL interface is critical for overall PEMWE efficiency.
• Optimized MPLs, particularly those with smaller pores, are essential for improving catalyst utilization and reducing energy losses in PEMWE.
• The decal-transfer method offers a viable approach for fabricating effective MPLs, contributing to more economical PEMWE systems.