Synthesis and characterization of novel acid–base polymer blends for application in membrane fuel cells

Kerres, Jochen; Ullrich, A.; Meier, F.; Häring, Thomas

doi:10.1016/s0167-2738(99)00181-2

Cited by 449 publications

(255 citation statements)

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“…This indicates there is a strong dependence of polymerization process on both doping level and conductivity, and is reiterated by Bai and Ho in their work. 33 Typical doping levels reported in the literature for m-PBI prepared via the conventional organic solvent route are between 6 and 10 mol PA/PBI, 14,15,[17][18][19][20][21] although some films with higher doping levels and poor mechanical properties have been achieved. 52 Average doping levels for s-PBI membranes developed in this work are between 30 and 35 mol PA/PBI, although some membranes retain 40-50 mol PA/PBI.…”

Section: Resultsmentioning

confidence: 99%

Sulfonated Polybenzimidazoles for High Temperature PEM Fuel Cells

2010

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High molecular weight, highly PA-doped s-PBI membranes have been developed with robust mechanical properties and excellent proton conductivities (>0.1 S cm -1 ) at elevated temperatures (>100°C). These membranes show high PA loadings of 30-35 mol PA/PBI, and average tensile stress and strain of 0.804 MPa and 69.64%, respectively. Proton conductivities were dependent on the acid doping level and measured between 0.1 and 0.25 S cm -1 at 180°C, a pronounced increase over most phosphoric acid-doped sulfonated PBI membranes to date. Preliminary fuel cell testing with hydrogen fuel and air or oxygen oxidants was performed at temperatures greater than 100°C without external feed gas humidification and show excellent performance (0.62-0.68 V at 0.2 A cm -2 and 160°C, hydrogen/air; 0.69-0.76 V at 0.2 A cm -2 and 160°C, hydrogen/oxygen). Initial performance stability studies were conducted for ∼3000 h and indicate great promise as high temperature membranes, with a degradation rate of 30 μV h -1 .

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Section: Resultsmentioning

confidence: 99%

Sulfonated Polybenzimidazoles for High Temperature PEM Fuel Cells

2010

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“…Nuclear magnetic resonance (NMR) spectra were recorded on a Varian Unity Inova 400 NMR spectrometer operating at a resonance frequency of 399.95 MHz for 1 H NMR and at 100.579 MHz for 13 C NMR. The 1D and 2D hydrogen NMR spectra were recorded using a 5-mm indirect detection probe, whereas the 1D and 2D carbon spectra were acquired using a 10-mm broadband probe.…”

Section: Nmrmentioning

confidence: 99%

“…NMR spectroscopy (1D 1 H, 13 C and 2D 1 H-1 H, 1 H-13 C correlation) was used as the principal method for characterization of the SPAEK-NA polymers in the sodium salt form. Polymer samples were dissolved in DMSO-d 6 for spectroscopic a Percentage of sulfonated monomer ϭ SDFBP-Na/(DFBP ϩ SDFBP-Na) ϫ 100, as shown in Scheme 1.…”

Section: Nmr Analysismentioning

confidence: 99%

“…1,2 Therefore, alternative and more economical nonperfluorinated polymer PEM materials for higher temperature applications are being investigated. Sulfonated derivatives of aromatic polymers, 3 such as poly(ether ether ketone) (PEEK), 1,4 -11 poly(ether sulfone) (PES), 12,13 polyimide (PI), 14 -16 and poly(benzimidazole) (PBI), 17 have been widely investigated for use as PEM materials because of their excellent chemical stability, high thermo-oxidative stability, good mechanical properties, and lower cost. Enhanced proton conductivity, hydrophilicity, and increased solubility in solvents for processing are useful properties for PEMs to have that can be accomplished by the introduction of sulfonic acid groups into the polymer.…”

Section: Introductionmentioning

confidence: 99%

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Sulfonated poly(aryl ether ketone)s containing naphthalene moieties obtained by direct copolymerization as novel polymers for proton exchange membranes

Xing

Robertson²,

Guiver³

et al. 2004

J. Polym. Sci. A Polym. Chem.

138

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A series of sulfonated poly(aryl ether ketone)s (SPAEKs) were prepared by aromatic nucleophilic polycondensation of 2,6-dihydroxynaphthalene with 5,5Ј-carbonyl-bis(2-fluorobenzenesulfonate) and 4,4Ј-difluorobenzophenone. The structure and degree of sulfonation (DS) of the SPAEKs were characterized using 1 H NMR spectroscopy. The experimentally observed DS values were close to the expected values derived from the starting material ratios. The thermal stabilities of the SPAEKs were characterized by thermogravimetric analysis, which showed that in acid and sodium salt forms they were thermally stable in air up to about 240 and 380°C, respectively. Transparent membranes cast from the directly polymerized SPAEKs exhibited good mechanical properties in both dry and hydrated states. The dependence of water uptake and of membrane swelling on the DS at different temperatures was studied. SPAEK membranes with a DS from 0.72 to 1.60 maintained adequate mechanical properties after immersion in water at 80°C for 24 h. The proton conductivity of SPAEK membranes with different degrees of sulfonation was measured as a function of temperature. The proton conductivity of the SPAEK films increased with increased DS, and the highest room temperature conductivity (4.2 ϫ 10 Ϫ2 S/cm) was recorded for a SPAEK membrane with a DS of 1.60, which further increased to 1.1 ϫ 10 Ϫ1 S/cm at 80°C.

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“…Sulfonation on an electron poor position (i.e., diphe nylsulfone rings) must allow for a decrease in the de sulfonation of the ionomers and a slight increase in the dissociation of the sulfonic acids. Kerres et al [14] previously proposed a 3 step reaction that leads to these alternative ionomers. This clever approach led to a wide variety of structured polysulfone ionomers.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical and structural characterization of sulfonated polysulfone

et al. 2015

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a b s t r a c tWe describe the synthesis, as well as the electrochemical and structural characterization, of sulfonated polysulfone intended for use in PEM fuel cells. Starting from a commercial polysulfone, we assessed the performance of these prepared ionomers using synthesis protocols compatible with industrial produc tion. The efficiency of the trimethylsilyl chlorosulfonate and chlorosulfonic acid reagents in the sulfo nation process was confirmed by 1 H NMR, FTIR, elemental analysis, chemical titration and thermal analysis (DSC and TGA). Chlorosulfonic acid was the most effective sulfonation reagent. However, based on SEC MALLS, this reagent induced degradation of the backbone that is detrimental to the thermo mechanical stability and lifespan of the membranes. The electrical characterization of the membranes was undertaken using impedance spectroscopy in contact with different HCl aqueous solutions at various temperatures. The activation energies, which ranged from 8.2 to 11 kJ/mol, were in agreement with the prevailing proton vehicular mechanism.

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Synthesis and characterization of novel acid–base polymer blends for application in membrane fuel cells

Cited by 449 publications

References 6 publications

Sulfonated Polybenzimidazoles for High Temperature PEM Fuel Cells

Sulfonated Polybenzimidazoles for High Temperature PEM Fuel Cells

Sulfonated poly(aryl ether ketone)s containing naphthalene moieties obtained by direct copolymerization as novel polymers for proton exchange membranes

Electrochemical and structural characterization of sulfonated polysulfone

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