Elucidating High-Potential Degradation Mechanisms in Proton Exchange Membrane Fuel Cells

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Proton exchange membrane fuel cells (PEMFCs) face durability challenges from carbon corrosion under high-potential conditions.
• The interplay between carbon corrosion and performance decline in PEMFCs is not fully understood, hindering catalyst layer design.

Purpose of the Study:

• To develop a multiscale model integrating carbon corrosion, platinum degradation, and oxygen transport in the cathode catalyst layer (CCL).
• To elucidate the mechanisms of coupled degradation processes and their impact on PEMFC durability.

Main Methods:

• Development of a multiscale CCL degradation model.
• Integration of carbon corrosion, platinum degradation, and oxygen transport phenomena.
• High-resolution characterization techniques to analyze degradation post-testing.

Main Results:

• Stage-dependent carbon corrosion and electrochemical active surface area (ECSA) loss observed, with significant degradation in early cycles.
• Degradation rate slows over time due to surface functional group changes and altered corrosion pathways.
• Carbon corrosion accounts for 66.8% of ECSA loss via platinum detachment; ionomer film thickening increases oxygen transport resistance by 55.1%.

Conclusions:

• The study provides mechanistic insights into coupled degradation in PEMFCs under high-potential stress.
• Carbon corrosion is a primary driver of performance loss, impacting both platinum utilization and oxygen transport.
• Findings offer guidance for designing more durable CCLs for fuel cell applications.