The conductivity of pyrrolidinium and sulfonylimide based ionic liquids: A combined experimental and computational study

Ionic conductivity is a fundamental property of ionic liquids with its origin and exact nature under debate. Using a specially selected system of pyrrolidinium cations (PYR1x, x = 3,4) and sulfonylimide anions (FSI, TFSI, BETI, and IM14)-based ionic liquids we observe a simple and accurate connection between ab initio computed cation and anion volumes and measured molar ionic conductivities

Thermally cured semi-interpenetrating electrolyte networks (s-IPN) for safe and aging-resistant secondary lithium polymer batteries

Truly solid polymer electrolyte membranes are designed by thermally induced free radical polymerisation. The overall membrane architecture is built on a semi-interpenetrating polymer network (s-IPN) structure, where a di-methacrylate oligomer is cross-linked (in situ) in the presence of a long thermoplastic linear PEO chain and a supporting lithium salt to obtain a freestanding, flexible and non-tacky film. In the envisaged systems, the di-methacrylate functions as a soft cross-linker, thus avoiding physico-mechanical deformation of the s-IPNs at elevated temperature, without hampering the ionic conductivity. s-IPNs exhibit remarkable stability towards lithium metal and no traces of impurity are detected while testing their oxidation stability (4.7 V vs. Li/Li+) towards anodic potential. The newly elaborated system is also successfully tested at moderately high temperature in Li metal cells in which LiFePO4/C is used as the cathode active material, showing excellent indications of safe and highly durable electrolyte separator (i.e., 2000 cycles at reasonably high 1C rate

Hot –pressed, solvent-free, nanocomposite, PEO-based electrolyte membranes II. All solid-state Li/LiFePO4 polymer batteries

The application and characteristics of hot-pressed, nanocomposite, polyethyleneoxide (PEO)-based electrolyte membranes in all solid-state rechargeable, Li/LiFePO4 polymer cells are presented and discussed. Both electrolyte separators and LiFePO4 composite cathodes were prepared by hot-pressing by a completely dry, solvent-free procedure. The thermal stability of both the PEO membranes and the composite cathodes was investigated. The cells were assembled by the direct lamination of the components, namely a lithium foil anode, the PEO-based electrolyte membrane and the composite LiFePO4 cathode tape. The Li/LiFePO4 polymer cells perform well in terms of specific capacity, charge/discharge efficiency and cycle life. At temperatures above 90 °C, the cells are capable of delivering capacities exceeding 100 mAh/g, even at moderately high rates. More than 400 cycles were obtained with a charge/discharge efficiency approaching 100%

Nanoscale organization in piperidinium based room temperature ionic liquids

Here we report on the complex nature of the phase diagram of N-alkyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide ionic liquids using several complementary techniques and on their structural order in the molten state using small-wide angle x-ray scattering. The latter study indicates that the piperidinium aliphatic alkyl chains tend to aggregate, forming alkyl domains embedded into polar regions, similar to what we recently highlighted in the case of other ionic liquids. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3119977

An advanced ionic liquid-lithium salt electrolyte mixture based on the bis(fluoromethanesulfonyl)imide anion

An innovative electrolyte mixture, based on the novel N-butyl-N-ethylpyrrolidinium bis(fluoromethanesulfonyl)imide (PYR24FSI) ionic liquid and the LiFSI lithium salt, was prepared and its thermal and ion-transport properties were investigated. The FSI-based mixture showed fast crystallization kinetics with melting point around −40 °C. A conductivity close to 4 × 10−3 S cm−1 was reached at room temperature. This PYR24FSI-LiFSI mixture family has been found to be an appealing electrolyte for high safety and performance lithium battery systems. Keywords: N-butyl-N-ethylpyrrolidinium, Bis(trifluoromethanesulfonyl)imide, Bis(fluorosulfonyl)imide, Ionic liquid electrolyte

Novel polymeric systems for lithium ion batteries gel electrolytes: II. Hybrid cross-linked poly(fluorosilicone-ethyleneoxide)

International audienc