Three-phase microenvironment modification by optimizing ionomer towards high-performance proton exchange membrane...

Area of Science:

• Electrochemistry and Materials Science
• Energy Conversion Technologies

Background:

• Proton exchange membrane fuel cells (PEMFCs) are key to clean energy, with oxygen reduction reaction (ORR) efficiency critical for performance.
• Mass transport limitations at the catalyst layer's three-phase boundary (TPB) hinder ORR kinetics, impacting platinum (Pt) utilization.
• Current linear ionomers, while conductive, impede oxygen transport and water management.

Purpose of the Study:

• To review mechanisms of transport (proton, water, gas) within ionomers in PEMFC catalyst layers.
• To highlight advanced characterization techniques for catalyst activity and microenvironment analysis.
• To explore novel strategies for optimizing ionomer-catalyst interfaces for enhanced fuel cell performance.

Main Methods:

• Review of fundamental transport phenomena in ionomers.
• Analysis of characterization methods for catalyst layers (CLs).
• Synthesis and evaluation of structurally engineered ionomers and catalyst layer designs.

Main Results:

• Tailoring ionomer structure significantly optimizes the microenvironment for ORR.
• Open framework ionomers demonstrate superior mass transport properties.
• Structural ionomer regulation and rational CL design enhance Pt utilization and fuel cell activity.

Conclusions:

• Optimized ionomer design is essential for overcoming mass transport limitations in PEMFCs.
• Advanced ionomers, particularly open framework types, promise improved fuel cell efficiency and durability.
• Further research into ionomer mechanisms and materials will accelerate the commercialization of hydrogen fuel cells.