Abstract Although the peak power density of anion exchange membrane fuel cells (AEMFCs) has been raised from ≈0.1 to ≈1.4 W cm −2 over last decade, a majority AEMFCs reported in literature have not demonstrated achieve consistently high performance and steady‐state operation. Poly(olefin)‐based AEMs with fluorine substitution on aromatic comonomer show considerably higher dimensional stability compared samples that do contain fluorine. More importantly, fluorinated poly(olefin)‐based exhibit...

This paper presents an overview of the key requirements for proton exchange membranes (PEM) used in fuel cell applications, along with a description membrane materials currently being and their ability to meet these requirements. Also discussed are some new materials, technologies, research directions pursued try demanding performance durability needs PEM industry.

Bromoalkyl-functionalized poly(olefin)s were synthesized by copolymerization of 4-(4-methylphenyl)-1-butene with 11-bromo-1-undecene using Ziegler–Natta polymerization. The resulting bromoalkyl-functionalized converted to quaternary ammonium-containing anion-conductive copolymers reacting the pendant bromoalkyl group trimethylamine or a custom-synthesized tertiary amine containing ammonium moieties. Poly(olefin)-based AEMs three cations per side chain showed considerably higher hydroxide...

Abstract Ionomers are important to electrode function in energy conversion devices, such as fuel cells and electrolyzers, the catalyst‐binding nanometer‐thick films under confinement, which compromises mass transport of species. Mitigating confinement effects is necessary for improved performance polymer electrolyte cells. Studies on perfluorosulfonic acid (PFSA) ionomers provided insights into origins resistances, but limited improvements by current strategies necessitate a need alternative...

An extensive SAXS investigation of the 3M perfluorinated sulfonic acid ionomer was performed to investigate morphological changes that occur during and after annealing at temperatures above Tα. The effect film thickness in range studied, 11–45 μm, found be negligible. These properties were studied as a function equivalent weight from 700 1100 correlated with water uptake measured by dynamic vapor sorption. Isoscattering points observed experiments unboiled annealed films q = 0.023, 0.096...

The performance of ion-conducting polymer membranes is complicated by an intricate interplay between chemistry and morphology that challenging to understand. Here, we report on perfuoro ionene chain extended (PFICE) ionomers contain either one or two bis(sulfonyl)imide groups the side-chain in addition a terminal sulfonic acid group. PFICE exhibit greater water uptake conductivity compared prototypical perfluorinated ionomers. Advanced situ synchrotron characterization reveals insights into...

Polymer-electrolyte membranes (PEMs) are a key component in electrochemical energy conversion devices where their main function is to selectively transport ionic species. Reducing PEM thickness an effective strategy for improving performance by minimizing losses. However, how affects the intrinsic properties of membrane remains unexplored. This work aims understand effect on structure-property relationships 3 M perfluorosulfonic acid (PFSA) ionomer. We carried out systematic investigation...

Hydrocarbon ionomers are a fluorine-free alternative to perfluorinated sulfonic acid ionomers. To be viable the conductivity gap between must closed, this analysis explains and explores strategies achieve this.

Highly conducive to high conductivity: Polyoxometalates were incorporated in the backbone of a hydrocarbon polymer produce proton-conducting films. These first-generation materials contain large, dispersed clusters polyoxometalates. Although morphology these films is not yet optimal, they already demonstrate practical proton conductivities and diffusion within appears be very high.

There is a critical need for higher performing proton exchange membranes electrochemical energy conversion devices that would enable temperature and drier operating conditions to be utilized. A novel approach utilize multiacid side chains in perfluorinated polymer, maintaining the mechanical properties of material, while dramatically increasing ion-exchange capacity; however, as we show this paper, more complex chain gives rise unexpected physical phenomena material. We have thoroughly...

Proton exchange membranes based on perfluorosulfonic acid (PFSA) ionomers are the industry standard for proton membrane fuel cells. These offer remarkable conductivity and chemical stability, especially when fully hydrated with water. Performance, however, rapidly decreases as dry out, thereby requiring external humidification equipment. Because of this, there exists a need new that can maintain high at low levels. Perfluoro bissulfonimides have strengths similar to those sulfonic acids be...

Recent work at 3M has focused on the development of solvent cast proton exchange membranes (PEM's) for use in PEM fuel cells. These new are a perfluorinated sulfonic acids based low molecular weight monomer and they exhibit excellent mechanical properties chemical stability high ionic conductivity. The allows with equivalent as 800 g/mole to have good when hydrated. Stabilizing additives these been shown improve oxidative Fenton's tests. Physical property, conductivity cell tests performed....

Anion exchange membranes (AEMs) are of high interest for a number electrochemical device applications including fuel cells, electrolyzers, and flow batteries. Perfluorinated sulfonic acid polymers have been the standard polymer used in much more established area proton membrane based devices due to specific advantageous attributes chemical stability, conductivity, water mobility, ability create performance electrodes. These would make desirable AEMs, but synthesizing perfluorinated AEMs has...

Membranes based on 3M's perfluoro imide acid (PFIA) ionomer have been studied using the open circuit voltage (OCV) hold accelerated stress test. For these samples, a decay in OCV potential within first 200 hours was observed along with an increase cell resistance that rapidly grows near end of life. A multi-membrane electrode assembly (MEA) technique employed to study origins phenomena. Effluent water collected at beginning life and later, during recovery protocol, analyzed liquid...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMesophase behavior in thermotropic polyethers based on the semi-flexible mesogen 1-(4-hydroxyphenyl)-2-(2-methyl-4-hydroxyphenyl)ethaneMichael A. Yandrasits, Stephen Z. D. Cheng, Anqiu Zhang, Jinlong Bernhard Wunderlich, and Virgil PercecCite this: Macromolecules 1992, 25, 8, 2112–2121Publication Date (Print):April 1, 1992Publication History Published online1 May 2002Published inissue 1 April...

The temperature induced dehydration process of the 3M Brand perfluoroimide acid (PFIA), an advanced proton exchange membrane for fuel cells, was studied by in situ infrared spectroscopy to understand transport processes under conditions low hydration levels. A comprehensive assignment vibrational bands PFIA mid region is provided. Investigation kinetics conjunction with 2D correlation methods revealed sequential and a conclusive model. results indicate that at lower water content sulfonate...

Studies of proton transport in novel materials are important to enable a large array electrochemical devices. In this study, we show that heteropoly acids (HPAs) when immobilized polymer matrixes have highly mobile protons. Divinyl-11-silicotungstic acid, an HPA, was copolymerized with butyl acrylate and hexanediol diacrylate at various weight percentage loadings from 25% 85% using UV initiated polymerizations. The resultant films were tan colored flexible sheets ca. 120 μm thickness....

Hydrogen permeation was measured at 80 °C and four humidities for a series of membranes fabricated from the three most common perfluorosulfonic acid (PFSA) ionomers. In addition, were made with different thicknesses types expanded PTFE (ePTFE) reinforcements. A picture has emerged where constant is lowest shortest side chain decreases decreasing ion exchange capacity (IEC). relationship quantifying impact ePTFE on reducing hydrogen developed showing lower cross over higher fiber content. For...

Unraveling ion conduction limitations in nanothin ionomer films is crucial for designing efficient ionomer–catalyst interfaces and improving redox efficiency electrochemical devices. This work took a multifaceted approach to understand local proton environments sub-μm thick of three fluorocarbon-based ionomers, Nafion, 3M PFSA PFIA with IEC ∼ 0.91, 1.21, 1.61 mequiv/g, respectively. After incorporating fluorescent photoacid probe pyranine (HPTS) into films, the extent (Id/Ip), concentration,...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolid-state carbon-13 NMR studies of molecular motion in MBPE-9 and MBPE-5Jinlong Cheng, Yimin Jin, Bernhard Wunderlich, Stephen Z. D. Michael A. Yandrasits, Anqiu Zhang, Virgil PercecCite this: Macromolecules 1992, 25, 22, 5991–5999Publication Date (Print):October 1, 1992Publication History Published online1 May 2002Published inissue 1 October 1992https://pubs.acs.org/doi/10.1021/ma00048a021https://doi.org/10.1021/ma00048a021research-articleACS...

Abstract This work presents a new method to measure simultaneously the dielectric loss factor and viscosity of thermosetting polymers during various cure cycles. A microdielectric sensor was mounted in bottom plate parallel rheometer. Three types high performance laminating resins were investigated. During non‐isothermal curing, dipole peaks found correspond softening/devitrification, maximum followed same heating rate dependence as minimum viscosity, observed correlate with vitrification...