Deciphering the long-term failure mechanism of the sealing framework in a proton exchange membrane fuel cell by assessing multi-stress degradation under accelerated simulated operating conditions

초록

While proton exchange membrane fuel cells (PEMFCs) are eco-friendly and sustainable energy sources that address environmental issues associated with fossil-fuel consumption, their membrane electrode assemblies are often poorly bonded to other key components. Herein, we elucidated the long-term failure mechanism of the sealing framework in a PEMFC by assessing multi-stress degradation under accelerated simulated operating conditions. A comprehensive stress protocol that applies voltage under both acidic and Fenton conditions along with thermal cycling was used to examine interfacial integrity over time. Peel-strength measurements, combined with Fourier-transform infrared spectroscopy, atomic force microscopy, field-emission scanning electron microscopy, and water uptake analyses, revealed progressive shifts in degradation mode. Electrochemical oxidation and electro-osmosis led to deterioration that was initially localized at the adhesive-membrane interface, after which the structure of the membrane-membrane interface weakened during prolonged exposure. Chemical degradation was significantly accelerated by Fenton-induced hydroxyl radicals, whereas the electrochemical response was modulated by thermal cycling, leading to a deviation in the failure trajectory even when stressed by constant-voltage conditions. These findings highlight how chemical, thermal, and electrochemical stressors synergistically influence the durability of PEMFC sealing components and may serve as a foundational reference for developing highly durable sealing materials for next-generation fuel cell systems.

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