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International audienceThis paper deals with the performance of anhydrous proton-conducting polymers obtained by blending modified Nafion^® membranes with proton conducting ionic liquids (PILs). It has been shown that the conductivities depend more on the PIL uptake than on its intrinsic conductivity. Conductivities at 130°C approaching those of current Nafion membranes at 80°C and 98% relative humidity were obtained with the best blends. These data allow considering MEA operating at 120-130°C based on membrane and electrodes incorporating these blends. This is clearly a positive feature for an implementation in hybrid vehicles powered by proton exchange membrane fuel cells (PEMFCs) operating above 100°C. Lastly, preliminary results for a PIL based on a half-neutralized diamine show an improvement in oxidation and, provided that the neutralization is optimized, a neat reinforcement of the Nafion membrane can be expected

The paper deals with proton‐conducting ionic liquids (PCILs) for use, in combination with functional polymers, in membranes operating in high temperature PEMFC. Monoammoniums derived from monoamines and half‐neutralised diamines were investigated in the form of triflates. Promising results were obtained with the half‐neutralised diamine‐based PCIL, its conduction being governed by both Grotthuss‐like and vehicular mechanisms, the respective contributions of which depend on temperature. In addition, their blending with Nafion results in a distinct reinforcement of the membrane.

International audienceThe effects of the incorporation of ethylene carbonate (EC) or dimethyl carbonate on the physicochemical and electrochemical properties of ionic liquids (ILs) based on aliphatic quaternary ammonium and imide anion were studied. The evolution of the melting point, glass transition, ionic conductivity, diffusion coefficient, and electrochemical stability were evaluated. The addition of a low amount of solvent, that is, 20 wt %, allows us to improve significantly the conductivity values, reaching 12 mS/cm at 40 °C. The incorporation of a polar solvent, EC, has no positive effect on the IL dissociation. Moreover, the incorporation of EC in ILs improves the electrochemical stability toward reduction, whereas the high anodic stability is maintained. The addition of LiTFSI in IL + solvent electrolytes has been investigated. Although this addition reduces the ionic conductivity, this decrease is less pronounced than in pure ILs, showing the beneficial effect of the additive solvent

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A new class of electrolyte based on TFSI and triphenolate-borohydride anions was designed and produced which fulfill all requirements of easy synthesis, high ionic conductivity, wide potential window, and noncorrosion of Al current collector. The electrolyte composed of magnesium triphenolate borohydride and Mg(TFSI) in glyme simultaneously displays a high conductivity of 5.5 mS cm at 25 °C and a reversible Mg plating/stripping with high current density and Coulombic efficiency at room temperature. By addition of a slight amount of MgCl to this electrolyte, a Coulombic efficiency of 90% in an SS/Mg cell, stable cycling performance, and a wide anodic potential of 3.4 V vs Mg/Mg on Al current collector can be reached. Reversible and efficient Mg insertion/deinsertion with a high capacity of 94 mAh g and 96% Coulombic efficiency was obtained in a MoS Chevrel cathode phase.

International audienceIonic liquids, ILs, based on fluorinated pyrrolidi- nium and piperidinium ammonium cations and imide anion were prepared and characterized. The physicochemical and electrochemical properties of these ILs including melting point, glass transition and degradation temperatures, viscosity, ionic conductivity, and electrochemical stability were deter- mined and compared to alkyl pyrrolidinium and piperidinium ILs. The incorporation of a CF3 group instead of a CH3 induces an increase of the IL viscosity, thus a conductivity decrease. However, good ionic conductivity is obtained with fluorinated pyrrolidinium IL. Cyclic amine ILs with propyl alkyl chain or fluorinated ammonium exhibit very high electrochemical sta- bility toward oxidation. The effect of the addition of LiTFSI on the IL properties was studied with the same methodology

The extraction mechanism of Pt(IV) from aqueous HCl solutions towards the ionic liquid 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C 1 C 8 IM][NTf 2 ]) is deciphered. To that end, aqueous speciation of Pt(IV) as a function of HCl was studied by 195 Pt NMR. Influence of the concentration of HCl (ranging from 1 to 12 M) and of the initial concentration of Pt (IV) (ranging from 10 À5 to 10 À2 M) in the aqueous phase on the distribution coefficients of Pt(IV) was systematically investigated. The decrease in D with the concentrations of HCl and Pt(IV) observed is quantitatively very well described with a model using three chemical equilibria, namely the solubility of the ionic liquid in water, the extraction of PtCl 6 2À through an ion-pair formation and that of Cl À towards the ionic liquid phase. D values were then predicted over a wider range of concentrations for HCl and PtCl 6 2À. Alternatively, the extraction of PtCl 6 2À was described using an anion exchange hypothesis and it is demonstrated that these two apparently different mechanisms are actually equivalent within hydrophobic ionic liquids. Because the two versions of the extraction model presented here are not specific to PtCl 6 2À or the ionic liquid, they can be generalized to the extraction of any charged (metal) complex and any hydrophobic ionic liquid, allowing us to outline a general uncertainty principle in the determination of extraction mechanisms in systems involving ionic liquids [a] Prof. N. Papaiconomou