Preparation and characterization of PTFE based composite anion exchange membranes for alkaline fuel cells

Zhao, Yun; Yu, Hongmei; Xing, Deke; Lu, Wenxian; Shao, Zhigang; Yi, Baolian

doi:10.1016/j.memsci.2012.07.034

Cited by 38 publications

(19 citation statements)

References 29 publications

(29 reference statements)

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“…The IEC value of the CQPECH/PTFE/OH -membrane was lower than those in some researches, but it was still higher than that of Nafion 112 [38]. The hydroxide conductivity of CQPECH/PTFE/OH -membrane in deionized water was 0.022 S/cm at 80°C, which was comparable with that of other PTFE composite anion exchange membrane [7]. The water uptake and swelling ratio of the conducting membrane were highly correlated to the cell performance.…”

Section: Mechanical Propertymentioning

confidence: 53%

“…High anionic conductivity, good stability and excellent mechanical strength of AEMs are essential for ensuring the sustainable and durable operations of AAEMFCs [7]. A series of membrane materials have been reported for the applications of AEMs, including poly(arylene ether sulfone) [8,9], poly(ether-imide) [10], cardo polyetherketone [11], poly(aryl ether oxadiazole) [12], poly(2,6-dimethyl-1,4-phenylene oxide) [13][14][15], poly(ether ether ketone) [16], poly(aryl ether oxadiazole) [17], poly(ethylene-co-tetrafluoroethylene) [18,19], poly(vinyl alcohol) [20], etc.…”

Section: Introductionmentioning

confidence: 99%

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Using diethylamine as crosslinking agent for getting polyepichlorohydrin-based composite membrane with high tensile strength and good chemical stability

Zhang

Liu

et al. 2016

Polym. Bull.

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A composite anion exchange membrane of crosslinked quaternized polyepichlorohydrin/polytetrafluoroethylene (CQPECH/PTFE) had been prepared via a green and facile method, where diethylamine, 1-methylimidazole and PTFE, respectively, served as crosslinking agent, quaternization reagent and supporting material. The structure and morphology of CQPECH/PTFE membrane were investigated. Water uptake, swelling ratio, ionic exchange capacity, hydroxide conductivity, chemical stability, and thermal and mechanical properties were measured to evaluate its performance in a direct methanol alkaline fuel cell. The results indicated that CQPECH had penetrated into the pores of PTFE membrane, showing a dense and uniform structure without any pore and phase separation. Besides, CQPECH/PTFE membrane exhibited high ionic conductivity, considerable ionic exchange capacity, moderate water uptake and low swelling ratio. More importantly, the obtained composite membrane displayed high tensile strength and good chemical and thermal stability, suggesting the great potential application of CQPECH/PTFE membrane as anion exchange membrane.Graphical abstract Crosslinked quaternized polyepichlorohydrin/polytetrafluoroethylene composite anion exchange membrane had been prepared via a green and facile method, where diethylamine served as crosslinking agent. With a dense and uniform structure without any pore and phase separation, the obtained composite membrane exhibited high tensile strength and good chemical stability.

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Section: Mechanical Propertymentioning

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Using diethylamine as crosslinking agent for getting polyepichlorohydrin-based composite membrane with high tensile strength and good chemical stability

Zhang

Liu

et al. 2016

Polym. Bull.

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“…The analysis was performed in nitrogen to separate carbon from the other materials contained within the GDL. No significant decay in mass was observed below 300 o C. A mass drop was observed at 550 o C, which corresponds to the pyrolysis of PTFE [70,71]. GDL-A contains 5 wt%, whereas GDL-B contains 15 wt%.…”

Section: Thermogravimetric Analysismentioning

confidence: 92%

Effect of gas diffusion layer properties on water distribution across air-cooled, open-cathode polymer electrolyte fuel cells: A combined ex-situ X-ray tomography and in-operando neutron imaging study

Meyer

Ashton

Boillat

et al. 2016

Electrochimica Acta

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2 Highlights First description of in-plane water distribution using neutron imaging in an aircooled, open-cathode fuel cell. High water content identified under cathode land area, whereas anode water content is relatively homogeneous. Water distribution in anode GDL directly linked to dispersion of PTFE. Anode GDL composition shown to affect water content and distribution in cathode. Combined X-ray computed tomography, SEM/EDS and TGA used to characterise GDL structure and composition. AbstractIn-situ diagnostic techniques provide a means of understanding the internal workings of fuel cells under normal operating conditions so that improved designs and operating regimes can be identified. Here, an approach is used which combines exsitu characterisation of two anode gas diffusion / microporous layers (GDL-A and GDL-B) with X-ray computed tomography and in-situ analysis using neutron imaging of operating fuel cells. The combination of TGA, SEM and X-ray computed tomography reveals that GDL-A has a thin microporous layer with 26 % PTFE covering a thick diffusion layer composed of 'spaghetti' shaped fibres. GDL-B is covered by two microporous media (29 % and 6.5 % PTFE) penetrating deep within the linear fibre network. The neutron imaging reveals two pathways for water management underneath the cooling channel, either diffusing through the cathode GDL to the active channels, or diffusing through the membrane and towards the 3 anode. Here, these two behaviours are directly affected by the anode gas diffusion PTFE content and porosity. KeywordsGas diffusion layer; air-cooled open-cathode; X-ray computed tomography; neutron imaging; water management. IntroductionPolymer electrolyte fuel cells (PEFC) fuelled with hydrogen are among the most promising energy conversion technologies for a broad range of applications, including portable, stationary and automotive power delivery. However, understanding the cell water management is crucial for performance optimisation.Flooding impedes reactant transport (water mainly concentrating at the cathode) and reduces the surface area of the catalyst, causing significant if not catastrophic decay in cell performance, and dehydration can lead to cracks and irreversible damage [1][2][3]. The gas diffusion layer (GDL) provides a pathway for electron transport, ensures even reactant delivery and helps water management within each cell. The water balance between flooding and membrane dehydration is a function of the GDL's structure, porosity and PTFE (hydrophobic) content. Here, two commercial GDLs with microporous layers are characterised ex-situ by capturing the design and structure via X-ray computed tomography (CT), along with its polytetrafluoroethylene (PTFE) / carbon distribution via SEM/EDS analysis and thermogravimetric analysis (TGA); in-situ 'visualisation' of the water distribution in the in-plane orientation was performed using neutron radiography. These techniques can be correlated with one another to gain new insights into the water management role of the GDL in fuel c...

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“…Meanwhile, a porous PTFE membrane was employed as the supporting material to further reinforce the composite membrane for an enhanced mechanical strength of the electrolyte membrane. 12,14,26,27,30,31 The specic benets of novel composite PECH-SiIm-MeIm/PTFE electrolytes include (i) a facile synthetic approach for imidazolium groups functionalized electrolytes avoiding chloromethylation reaction; (ii) high conductivities accompanying with good mechanical strengths by using a kind of imidazole based crosslinker of SiIm; (iii) good stability and low swelling due to the further enhancement of the supporting material PTFE. The properties of the PA doped novel HT-PEMs were comprehensively investigated including primary fuel cell tests at temperatures up to 180 C without humidication.…”

Section: Introductionmentioning

confidence: 99%

Phosphoric acid doped imidazolium silane crosslinked poly(epichlorihydrin)/PTFE as high temperature proton exchange membranes

et al. 2016

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Low cost poly(epichlorohydrin) (PECH) was modified with imidazolium groups to prepare high temperature proton exchange membranes. Chloromethyl groups in the structure of the PECH benefit its modification with no need for highly toxic and carcinogenic chloromethylation reagents. Both methylimidazole (MeIm) and triethoxysilylpropyldihydroimidazole (SiIm) were used to carry out the S N 2 nucleophilic substitution for grafting the imidazolium groups onto the PECH. Meanwhile crosslinking of the modified PECH was achieved by forming a crosslinked silane network via the hydrolysis reaction of SiIm in an acid medium. Moreover, porous poly(tetrafluoroethylene) (PTFE) was used as the membrane matrix to enhance the mechanical strength of the fabricated membranes. The obtained PECH-SiIm-MeIm/PTFE membranes displayed phosphoric acid doping capacities of 110-170 wt% with low volume swelling ratios of less than 120%. Anhydrous proton conductivities of 0.010-0.063 S cm À1 were reached at elevated temperatures of 100-180 C by the membranes with adequate mechanical strength. Fuel cell tests demonstrated the technical feasibility of acid doped PECH-SiIm-MeIm/PTFE membranes for high temperature proton exchange membrane fuel cells.

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Preparation and characterization of PTFE based composite anion exchange membranes for alkaline fuel cells

Cited by 38 publications

References 29 publications

Using diethylamine as crosslinking agent for getting polyepichlorohydrin-based composite membrane with high tensile strength and good chemical stability

Using diethylamine as crosslinking agent for getting polyepichlorohydrin-based composite membrane with high tensile strength and good chemical stability

Effect of gas diffusion layer properties on water distribution across air-cooled, open-cathode polymer electrolyte fuel cells: A combined ex-situ X-ray tomography and in-operando neutron imaging study

Phosphoric acid doped imidazolium silane crosslinked poly(epichlorihydrin)/PTFE as high temperature proton exchange membranes

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