Performance Degradation in Proton Exchange Membrane Fuel Cell Under Large Load Variation at Rapid Startup: Phenomena...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Conversion

Background:

• Proton exchange membrane fuel cells (PEMFCs) are crucial for clean energy, but their durability under dynamic operating conditions, especially rapid startup and load variations, remains a challenge for commercialization.
• Flow field design significantly impacts gas distribution, water management, and overall cell performance and longevity.

Purpose of the Study:

• To experimentally investigate and compare the performance degradation and membrane electrode assembly (MEA) deterioration of PEMFCs with parallel flow field (PFF) and five-channel serpentine flow field (FSFF) designs under rapid dynamic loads.
• To evaluate the effectiveness of FSFF in mitigating performance loss and MEA degradation compared to PFF.

Main Methods:

• PEMFCs with PFF and FSFF designs were subjected to 20,000 cycles of rapid dynamic loads with 2-second transients to 3000 mA cm⁻².
• Performance degradation was assessed through voltage loss measurements, while MEA deterioration was analyzed via electrochemical impedance spectroscopy (EIS) and spatial degradation analysis of catalyst layers.

Main Results:

• The FSFF design demonstrated significantly lower voltage degradation (9.11%) compared to the PFF design (20.77%) under dynamic loads.
• FSFF improved gas distribution uniformity and water removal, leading to reduced cathode charge transfer resistance and less electrochemical surface area degradation.
• Spatial analysis showed less catalyst layer thinning and reduced platinum particle agglomeration in the FSFF configuration, particularly in outlet regions.

Conclusions:

• The five-channel serpentine flow field (FSFF) design offers superior durability for PEMFCs under large load variations and rapid startup conditions compared to parallel flow fields (PFF).
• Effective gas distribution and water management provided by FSFF are key to mitigating performance degradation and preserving MEA integrity.
• Flow field design is a critical factor in optimizing the dynamic durability of PEMFCs for demanding applications.