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Impact of degradation and aging on properties of PFSA membranes for fuel cells

Abstract : Although proton-exchange membrane fuel cells (PEMFC) are nowadays considered as a safe and clean energy technology, they still suffer from durability and reliability issues restricting their widespread commercialization. Innumerable studies have already led to a better understanding of aging phenomena and highlighted membrane degradation as one of the main factors limiting PEMFC lifetime. This study aims at bringing some clarifications on the chemical and mechanical degradation mechanisms of membranes through ex-situ aging protocols as well as understanding the impact of these degradations on the membrane structure and functional properties. First, it was necessary to clarify the influence of Fenton’s reaction, an ex-situ aging protocol widely recognized in the literature, on the chemical degradation of Nafion™ membranes. The results confirmed that Fenton’s reagents concentration significantly influenced polymer chemical decomposition, both from a chemical and morphological point of view. Subsequently, we chose to monitor the evolution of pure chemical degradation of Nafion™ membranes as a function of time and to study its impact on the membrane structure, water sorption and diffusion properties, as well as operability in fuel cells. In that respect, various characterization techniques such as 19F or 1H-NMR as well as FTIR spectroscopies allowed us to correlate physico-chemical properties of the membrane to its structural characteristics and to thus highlight several indicators of chemical degradation. Finally, a custom-made device has been developed to study the impact of conjoint mechanical and chemical stress on Nafion™ membranes. The objective of this device was to replicate aging conditions close to those encountered during fuel cell operation.
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https://hal.univ-lorraine.fr/tel-03203250
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Submitted on : Tuesday, April 20, 2021 - 4:38:33 PM
Last modification on : Wednesday, April 21, 2021 - 3:23:50 AM

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  • HAL Id : tel-03203250, version 1

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Mylène Robert. Impact of degradation and aging on properties of PFSA membranes for fuel cells. Mechanics of materials [physics.class-ph]. Université de Lorraine, 2021. English. ⟨NNT : 2021LORR0004⟩. ⟨tel-03203250⟩

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