Predicting performance stability of anion exchange membrane fuel cells

Dekel, Dario R.; Rasin, Igal G.; Brandon, Simon

doi:10.1016/j.jpowsour.2019.02.069

Cited by 90 publications

(94 citation statements)

References 41 publications

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“…The nonacidic environment of AEMFCs allows the use of nonprecious metal catalysts, which intensely reduces the cost per kilowatt of power of fuel cell devices . In spite of the latest technological progress related to electrocatalysts and to the understanding of carbonation issues, one of the main remaining challenges in the AEMFCs is the availability of good, stable anion conducting membranes that enable the hydroxide anion and water conduction through the polymeric network, both as an anion exchange membrane (AEM) and as anion exchange ionomers (AEIs).…”

Section: Introductionmentioning

confidence: 99%

Electrospun Ionomeric Fibers with Anion Conducting Properties

Mann‐Lahav

Halabi

Shter

et al. 2019

Adv Funct Materials

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Anion conductive nanofiber mats from FAA-3 ionomers are obtained by electrospinning. Depending on the solvent used in the precursor solution, nanofibers with either nonhollow cylindrical or flat ribbon-like cross-sections are prepared. The anion conductivity and water uptake of the ionomeric nanofiber mats are measured as a function of the relative humidity in the 10-90% range and compared to that of a solid membrane cast from the same ionomer. In addition, the anion conductivity of an isolated single fiber of the ionomer is measured for the first time. The anion conductivity of the electrospun single fiber is found to be higher than that of the mats, which is, in turn, one order of magnitude higher than that of the solid ionomer membrane. The higher conductivity of the mats relative to the solid membrane (in both inplane and through-plane directions) is found to be related to the variation in water uptake, which stems from the morphological distinctions. These results increase the understanding of the electrospinning process of ionomers, toward the development and design of new anion conductive ionomer fibers, useful for high performance electrochemical devices.

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Section: Introductionmentioning

confidence: 99%

Electrospun Ionomeric Fibers with Anion Conducting Properties

Mann‐Lahav

Halabi

Shter

et al. 2019

Adv Funct Materials

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“…Dang reported a series of AEMs with comb-shaped side chain in which the cation groups are separated from the polymer backbone by the long flexible alkyl spacers, and the combshaped AEMs showed much higher alkaline stability than the traditional AEMs with benzyltrimethylammonium groups due to the low electro-withdrawing and steric effects on QA groups. Moreover, the introduction of the flexible spacer between QA cations and backbones enhanced the mobility of QA cations, which is favorable for the formation of distinct ionic clusters in membranes and enhanced the water transport in the membranes, thereby creating an environment that is less favorable for ionomer degradation (Hibbs, 2013;Dang and Jannasch, 2015;Dekel et al, 2019). Improved alkaline stability was observed for other AEMs with microphase separation structure based on various polymer backbones and cationic groups (Oh et al, 2018;Gao et al, 2019c;Han et al, 2019).…”

Section: Alkaline Stabilitymentioning

confidence: 98%

Progress of Alkaline Anion Exchange Membranes for Fuel Cells: The Effects of Micro-Phase Separation

Lin

2020

Front. Mater.

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Compared with that of proton exchange membrane fuel cells (PEMFCs), alkaline anion exchange membrane fuel cells (AEMFCs) with alkaline anion exchange membranes (AEMs) as electrolytes are attracting increased attention due to their potential use as non-precious catalysts. As one of the key components of AEMFCs, an ideal AEM must possess high hydroxide conductivity, good thermal stability, sufficient mechanical stability, and excellent long-term durability at elevated temperatures in an alkaline environment. Until now, a large number of AEMs with various chemical structures and properties have been prepared, and studied in detail, and it has been found that the microphase separation structure greatly affected the performance of AEMs. This minireview provides recent progress made of AEMs with hydrophilic/hydrophobic microphase separation structure. The hydroxide conductivity, alkaline stability, and mechanical properties of AEMs could be improved due to the formation of hydrophilic/hydrophobic microphase separation in the membranes. The relationship among the microphase separation, the chemical structure of the polymers, and the performance of membranes has been discussed in detail. This article attempts to give an overview of some key factors for the future design of novel AEMs with excellent performance such as high conductivity and improved chemical stability.

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“…In recent years, the synthesis of new QA salts has burst, given their potential use in anion‐exchange membrane fuel cells (AEMFCs) . AEMFC is a promising technology for affordable and efficient energy conversion but is currently limited by the chemical stability of the cationic functional groups that decompose under fuel cell operation , . Currently, no organic cation has proved to be stable enough to withstand the harsh combined alkaline and low hydration environment for the required lifetime of an AEMFC .…”

Section: Introductionmentioning

confidence: 99%

“…We have recently developed an improved procedure for the synthesis of N,N ‐diaryl carbazolium salts, which allows for the synthesis of a variety of derivatives with different substituents in very few synthetic steps and significantly better yields . Driven by previous studies that better simulate AEMFCs conditions by creating non‐aqueous alkaline and low hydration conditions,, , we expected that making such molecules and testing them under such conditions would open new pathways to developing more stable QAs, needed for durable AEMFCs . Importantly, by changing the mechanism of reaction with hydroxide, different molecular optimization can be used to further tackle the stability of transition states and intermediates, towards the production of kinetically stable QAs which will be able to survive the aggressive conditions present in AEMFC for the lifetime of the fuel cell.…”

Section: Introductionmentioning

confidence: 99%

The Reaction Mechanism Between Tetraarylammonium Salts and Hydroxide

et al. 2020

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The mechanism of the reaction between tetraaryl ammonium salts and hydroxide is studied experimentally for different N,N‐diaryl carbazolium salts. The N,N‐diarylcarbazolium salts are designed, synthesized, characterized, and reacted with hydroxide under different conditions. The products of the reactions were directly characterized or isolated when possible and, using different substituents, the reaction mechanisms were compared. An unexpected H/D exchange observed in these salts helped to discard the classical SNAr mechanisms, supporting instead a radical mechanism initiated by a single‐electron transfer from the hydroxide. By understanding the preferred reaction pathways, better quaternary ammonium salts can be designed to withstand aggressive alkaline environments, critical for many practical applications such as anion‐exchange membrane fuel cells.

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Predicting performance stability of anion exchange membrane fuel cells

Cited by 90 publications

References 41 publications

Electrospun Ionomeric Fibers with Anion Conducting Properties

Electrospun Ionomeric Fibers with Anion Conducting Properties

Progress of Alkaline Anion Exchange Membranes for Fuel Cells: The Effects of Micro-Phase Separation

The Reaction Mechanism Between Tetraarylammonium Salts and Hydroxide

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