Fluoroalkyl phosphonic acid radical scavengers for proton exchange membrane fuel cells

Agarwal, Tanya; Adhikari, Santosh; Kim, Yu Seung; Babu, Siddharth Komini; Ding, Tian; Bae, Chulsung; Pham, Nguyet; Lee, Seung Geol; Prasad, Ajay K.; Advani, Suresh G.; Sievert, Allen C.; Liyanage, Wipula P. R.; Hopkins, Timothy B.; Park, Andrew; Borup, Rodney L.

doi:10.1039/d2ta09421e

Cited by 9 publications

(4 citation statements)

References 36 publications

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“…The retardant effect of phosphorus-containing moieties is well-known in the literature . A recent study of phosphonic acid as radical scavenger has been published for membrane in FC, leading to improved FC durability …”

Section: Resultsmentioning

confidence: 99%

“…23 A recent study of phosphonic acid as radical scavenger has been published for membrane in FC, leading to improved FC durability. 24 Ex Situ Conductivity and Tensile Strength. The proton conductivity mechanism in PA-doped polymer area (PEMs) is similar to the one in PA. 25 This is due to the fact that PA is in a large excess, and the interaction with the polymer membrane is weak.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Ion-Pair Membrane Based on Imidazolium-Functionalized Poly(pentafluorostyrene) for High-Temperature Proton Exchange Membrane Fuel Cell Application

Cho,

Seiler,

Atanasova

et al. 2024

ACS Appl. Energy Mater.

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Herein, an ion-pair membrane based on imidazolium-functionalized poly(pentafluorostyrene) (Me-PPFSt-Im) for high-temperature fuel cell (HT-PEMFC) application is reported for the first time. The polyelectrolyte Me-PPFSt-Im was obtained via a two-step synthesis and characterized with respect to its electrochemical application. A mechanically stable membrane was prepared by blending Me-PPFSt-Im with polybenzimidazole (F6PBI) followed by doping with phosphoric acid (PA). Ex situ impedance tests revealed stable conductivity for at least 160 h. Heat resistance tests showed extended stability of the polymers and membranes in the presence of PA. The ion-pair membrane displayed superior performance, exhibiting 1.54 W cm −2 of peak power density at 180 °C in a H 2 /O 2 fuel cell (FC). Accelerated stress test was carried out by thermal cycling from 80 to 160 °C, and the ion-pair membrane showed no significant performance decay for 100 cycles. The membrane exhibited operational stability without any loss of performance for about 400 h in the FC. Postmortem analysis showed membrane thinning from 45 μm down to 10 μm without noticeable changes in the catalyst layer. KEYWORDS: high-temperature proton exchange membrane fuel cell (HT-PEMFC), ion-pair membrane, polymer ionic liquids, anion exchange membrane (AEM), imidazolium-functionalized poly(pentafluorostyrene) (PPFSt), phosphoric acid (PA) doping

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Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Ion-Pair Membrane Based on Imidazolium-Functionalized Poly(pentafluorostyrene) for High-Temperature Proton Exchange Membrane Fuel Cell Application

Cho,

Seiler,

Atanasova

et al. 2024

ACS Appl. Energy Mater.

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“…Various types of antioxidants that have been studied for their potential to improve the oxidative stability of perfluorosulfonic acid (PFSA) membranes include heteropolyacids (HPAs), [9] quinones, [10] phenols, [11] phosphonic acids, [12] and carboxylic acids. [8] While HPAs are known to scavenge radicals and enhance durability, their water solubility is concerning and they may suffer from similar issues as cerium.…”

Section: Introductionmentioning

confidence: 99%

“…[9,13] Phosphonic acids are promising radical scavenging alternatives to cerium but platinum poisoning due to phosphonic acid migration remains a concern. [12] Ferrocyanide/ferricyanide redox has been found to be an effective antioxidant strategy for PFSA and has been demonstrated to extend Nafion's durability in OCV test conditions. [14] While Nafion showed a 40% loss in OCV, ferrocyanide and ferricyanide-incorporated PFSA showed only a 2.2% loss in OCV for the same duration.…”

Section: Introductionmentioning

confidence: 99%

Biosourced Antioxidants for Chemical Durability Enhancement of Perfluorosulfonic Acid Membrane

Agarwal,

Adhikari,

Babu

et al. 2023

Adv Funct Materials

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The chemical durability of perfluorosulfonic acid (PFSA) membranes is a topic of growing interest to meet Department of Energy (DOE) durability targets for heavy‐duty vehicle (HDV) applications. State‐of‐the‐art membranes like Nafion, rely on the use of cerium, heteropolyacids, and other inorganic additives to increase PFSA chemical durability. A less explored avenue for the oxidative stabilization of PFSA and hydrocarbon membranes is the use of organic antioxidants. No reversible organic antioxidant has been demonstrated to date which can enhance membrane lifetime by factors comparable to cerium. Here, ellagic acid (EA) is demonstrated as a promising radical scavenger for PFSA's. It is found that the incorporation of EA enhances the chemical durability of Nafion by 160%. EA, when incorporated with cerium as an electron donorenhances Nafion durability by at least 80% compared to a membrane incorporated with just cerium in DOE‐defined durability tests. EA is found to be reversible in acidic conditions like those of fuel cells and its reversibility could be further enhanced by the use of suitable co‐antioxidants.

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Hydrocarbon Ionomeric Binders for Fuel Cells and Electrolyzers

Kim

2023

Advanced Science

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Ionomeric binders in catalyst layers, abbreviated as ionomers, play an essential role in the performance of polymer–electrolyte membrane fuel cells and electrolyzers. Due to environmental issues associated with perfluoroalkyl substances, alternative hydrocarbon ionomers have drawn substantial attention over the past few years. This review surveys literature to discuss ionomer requirements for the electrodes of fuel cells and electrolyzers, highlighting design principles of hydrocarbon ionomers to guide the development of advanced hydrocarbon ionomers.

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Fluoroalkyl phosphonic acid radical scavengers for proton exchange membrane fuel cells

Abstract: Radical-induced degradation of proton exchange membranes limits the durability of proton-exchange membrane fuel cells. Cerium is widely used as a radical scavenger, but the migration of cerium ions to the...

Cited by 9 publications

References 36 publications

Ion-Pair Membrane Based on Imidazolium-Functionalized Poly(pentafluorostyrene) for High-Temperature Proton Exchange Membrane Fuel Cell Application

Ion-Pair Membrane Based on Imidazolium-Functionalized Poly(pentafluorostyrene) for High-Temperature Proton Exchange Membrane Fuel Cell Application

Biosourced Antioxidants for Chemical Durability Enhancement of Perfluorosulfonic Acid Membrane

Hydrocarbon Ionomeric Binders for Fuel Cells and Electrolyzers

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