Modification of Nafion Membranes by Impregnation with Ionic Liquids

Schmidt, Christian; Glück, T.; Schmidt‐Naake, Gudrun

doi:10.1002/ceat.200700054

Cited by 114 publications

(97 citation statements)

References 26 publications

(23 reference statements)

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“…When Nafion, a current state-of-the-art PEM, is impregnated with different ILs, the reported anhydrous conductivity lies in the range of 0.001 − 0.1 S cm − 1 at 100 − 200 °C [24][25][26] . Note that the conductivities of Nafion/IL systems are significantly dependent on variables such as the sample preparation temperature and casting solvent [27][28][29] . The reason for this ambiguity is not entirely clear as the morphology of Nafion remains unresolved.…”

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confidence: 99%

Enhanced proton transport in nanostructured polymer electrolyte/ionic liquid membranes under water-free conditions

2010

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Proton exchange fuel cells (PEFCs) have the potential to provide power for a variety of applications ranging from electronic devices to transportation vehicles. A major challenge towards economically viable PEFCs is finding an electrolyte that is both durable and easily passes protons. In this article, we study novel anhydrous proton-conducting membranes, formed by incorporating ionic liquids into synthetic block co-polymer electrolytes, poly(styrenesulphonate-b-methylbutylene) (s n mB m ), as high-temperature PEFCs. The resulting membranes are transparent, flexible and thermally stable up to 180 °C. The increases in the sulphonation level of s n mB m co-polymers (proton supplier) and the concentration of the ionic liquid (proton mediator) produce an overall increase in conductivity. morphology effects were studied by X-ray scattering and electron microscopy. Compared with membranes having discrete ionic domains (including nafion 117), the nanostructured membranes revealed over an order of magnitude increase in conductivity with the highest conductivity of 0.045 s cm − 1 obtained at 165 °C.

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confidence: 99%

Enhanced proton transport in nanostructured polymer electrolyte/ionic liquid membranes under water-free conditions

2010

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“…Other considerations concern the degree of incorporation of the IL into the Nafion membrane, where the nature of the anion can also have a relevant role [2]. The incorporation of ILs in the structure of Nafion is under study [3][4][5].…”

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confidence: 99%

Chemical Surface, Thermal and Electrical Characterization of Nafion Membranes Doped with IL-Cations

et al. 2014

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Surface and bulk changes in a Nafion membrane as a result of IL-cation doping (1-butyl-3-methylimidazolium tetrafluoroborate or BMIM + BF 4 and phenyltrimethylammonium chloride or TMPA + Cl − ) were studied by X-ray photoelectron spectroscopy (XPS), contact angle, differential scanning calorimetry (DSC) and impedance spectroscopy (IS) measurements performed with dry samples after 24 h in contact with the IL-cations BMIM + and TMPA + . IL-cations were selected due to their similar molecular weight and molar volume but different shape, which could facilitate/obstruct the cation incorporation in the Nafion membrane structure by proton/cation exchange mechanism. The surface coverage of the Nafion membrane by the IL-cations was confirmed by XPS analysis and contact angle, while the results obtained by the other two techniques (DSC and IS) seem to indicate differences in thermal and electrical behaviour depending on the doping-cation, being less resistive the Nafion/BMIM + membrane. For that reason, determination of the ion transport number was obtained for this membrane by measuring the membrane or concentration potential with the samples in contact with HCl solutions at different concentrations. The comparison of these results with those obtained for the original Nafion membrane provides information on the effect of IL-cation BMIM + on the transport of H + across wet Nafion/BMIM + doped membranes. OPEN ACCESSAppl. Sci. 2014, 4 196

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“…This has made ILs interesting candidates for a number of applications including electrolytes for solar-cells [6], fluorescent [7] and optical devices [8]. So far, two routes have been highlighted for the incorporation of ILs in a gel; the organic route, which involves in situ polymerization or swelling of polymers with ILs [9,10], and the inorganic route, which consists of impregnation of ILs within oxide backbones [11]. Of the inorganic routes, the polymeric sol-gel process is probably the most popular synthetic route, as recently summarized in an excellent review [2].…”

Section: Introductionmentioning

confidence: 99%

Graphene-doped photo-patternable ionogels: tuning of conductivity and mechanical stability of 3D microstructures

et al. 2012

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This work reports for the first time the development of enhanced conductivity, graphenedoped photo-patternable hybrid organic-inorganic ionogels and the effect of the subsequent materials condensation on the conductivity and mechanical stability of threedimensional microstructures fabricated by multi-photon polymerisation (MPP). Ionogels were based on photocurable silicon/zirconium hybrid sol-gel materials and phosphonium (trihexyltetradecylphosphonium dicyanamide [P6,6,6,14][DCA] ionic liquid (IL). To optimise the dispersion of graphene within the ionogel matrices, aqueous solutions of graphene were prepared, as opposed to the conventional graphene powder approach, and employed as catalysts of hydrolysis and condensation reactions occurring in the sol-gel process.Ionogels were prepared via a two step process by varying the hydrolysis degree from 25 to 50%, IL content between 0-50 w/w%, and the inorganic modifier (zirconate complex) concentration from 30 to 60 mol.% against the photocurable ormosil and they were characterised via Raman, Electrochemical Impedance Spectroscopy and Transmission Electron Microscopy. MPP was performed on the hybrid ionogels, resulting in threedimensional microstructures that were characterised using scanning electron microscopy.It is clearly demonstrated that the molecular formulation of the ionogels, including the concentration of graphene and the zirconate network modifier, play a critical role in the conductivity of the ionogels and influence the resulting mechanical stability of the fabricated three-dimensional microstructures. This work aims to establish for the first time the relationship between the molecular design and condensation of materials in the physico-chemistry and dynamic of ionogels.3

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Modification of Nafion Membranes by Impregnation with Ionic Liquids

Cited by 114 publications

References 26 publications

Enhanced proton transport in nanostructured polymer electrolyte/ionic liquid membranes under water-free conditions

Enhanced proton transport in nanostructured polymer electrolyte/ionic liquid membranes under water-free conditions

Chemical Surface, Thermal and Electrical Characterization of Nafion Membranes Doped with IL-Cations

Graphene-doped photo-patternable ionogels: tuning of conductivity and mechanical stability of 3D microstructures

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