The Raman spectra of (1 − x)(BMITFSI), xLiTFSI ionic liquids, where 1-butyl-3-methylimidazolium cation (BMI + ) and bis(trifluoromethane-sulfonyl)imide anion (TFSI − ) are analyzed for LiTFSI mole fractions x < 0.4. As expected from previous studies on similar TFSI-based systems, most lithium ions are shown to be coordinated within [Li(TFSI) 2 ] − anionic clusters. The variation of the self-diffusion coefficients of the 1 H, 19 F, and 7 Li nuclei, measured by pulsed-gradient spin-echo NMR (PGSE-NMR) as a function of x, can be rationalized in terms of the weighted contribution of BMI + cations, TFSI − 'free' anions, and [Li(TFSI) 2 ] − anionic clusters. This implies a negative transference number for lithium.

MXenes are two-dimensional metal carbides or nitrides that are currently proposed in many applications thanks to their unique attributes including high conductivity and accessible surface. Recently, a synthetic route was proposed to prepare MXenes from the molten salt etching of precursors allowing for the preparation of MXene (denoted as MS-MXenes, for molten salt MXene) with tuned surface termination groups, resulting in improved electrochemical properties. However, further delamination of as-prepared multilayer MS-MXenes still remains a major challenge. Here, we report on the successful exfoliation of MS-Ti3C2T x via the intercalation of the organic molecule TBAOH (tetrabutylammonium hydroxide), followed by sonication to separate the layers. The treatment time could be adapted to tune the wetting behavior of the MS-Ti3C2T x . As a result, a self-supported Cl-terminated MXene film could be prepared by filtration. Finally, MS-Ti3C2T x used as a Li-ion battery anode could achieve a high specific capacity of 225 mAh g–1 at a 1C rate together with an excellent rate capability of 95 mAh g–1 at 167C. These results also show that tuning of the surface chemistry of MXene is of key importance to this field with the likely result being increased electrochemical performance.

International audienceNaSICON-type lithium conductor Li1.3Al0.3Ti1.7(PO4)3 (LATP) is synthesized with controlled grain size and composition using solution chemistry. After thermal treatment at 850 °C, sub-micronic crystallized powders with high purity are obtained. They are converted into ceramic through Spark Plasma Sintering at 850-1000 °C. By varying the processing parameters, pellet with conductivities up to 1.6 × 10−4 S/cm with density of 97% of the theoretical density have been obtained. XRD, FEG-SEM, ac-impedance and Vickers indentation were used to characterize the products. The influence of sintering parameters on pellet composition, microstructure and conductivity is discussed in addition to the analysis of the mechanical behavior of the grains interfaces

The performance of different poly(3,4-ethylenedioxythiophene) (PEDOT) films was compared by electrochemical, spectroelectrochemical, and time-derivative measurements of absorbance versus potential (linear potential-scan voltabsorptometry) for an overall spectroelectrochemical characterization of the electrochromic properties in ionic liquids such as 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMITFSI). The time-derivative signals were monitored at different wavelengths, and information obtained therefrom was complementary to that obtained from conventional cyclic voltammetry. PEDOT films prepared via in situ chemical oxidative polymerization appeared to be much more efficient than electropolymerized and PEDOT-poly(styrenesulfonate) (PSS) reference films, in terms of both contrast ratio and coloration efficiency, which was the case even for PEDOT films deposited on less conductive flexible plastic substrates.

Influence of the alloy microstructure and surface state on the protective properties of trivalent chromium coatings grown on a 2024 aluminium alloy. (2018) Surface and Coatings Technology, 344. 276-287.

Inorganic/organic (hybrid) complementary electrochromic devices (ECDs) of the type [transparent conducting oxide (TCO)//inorganic counter electrode/hydrophobic electrolytic membrane/polymeric working electrode//TCO] were assembled. The working electrodes consisted of spin-coated polymer films prepared by moderator-controlled in situ oxidative chemical polymerisation of 3,4-ethylene dioxythiophene (EDOT). Thin, galvanostatically deposited Prussian Blue (PB) films were employed as counter electrodes. Besides F : SnO 2 (FTO)/glass and Sn : In 2 O 3 (ITO)/glass, a flexible ITO/PET film was alternatively used for materials deposition. In order to attain the maximum device performance, the PB charge capacity was monitored and adapted to the capacity of the EDOT polymer films. The two electrochromic electrodes were separated by a novel hydrophobic polymer electrolyte based on a gel of 1-butyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide (BMI-TFSI) and poly(methylmethacrylate) (PMMA), with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as the salt. The influence of two parameters-ITO sheet resistance and the PMMA content in the electrolyte-on the final device properties was investigated. The ITO sheet resistance value proved to be crucial for the switching kinetics. The variation of the weight ratio of PMMA in the electrolyte showed that the effect on the kinetics is small whereas the change in absorbance is highly affected. The properties of the complementary glass-based devices were eventually compared to the corresponding plastic-based electrochromic elements. First attempts to scale up the technology were made for flexible 12 Â 15 cm 2 (active area) devices.

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The Raman and Infrared (IR) spectra of poly(methyl methacrylate) (PMMA) membranes plasticized by ionic liquids of the (1 − x)[1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMITFSI)],xLiTFSI type, where BMI + is the 1-butyl-3-methylimidazolium cation and TFSI− the bis(trifluoromethanesulfonyl)imide anion, are analyzed for a lithium bis(trifluoromethane sulfone)imide (LiTFSI) mole fraction x = 0.23 and PMMA contents from 0 to 50 wt%. The lithium is found to have an average coordination of about three C O groups and less than one TFSI − anion. It plays the role of a cross-linker between the ester groups of PMMA and the nonvolatile ionic liquid. Addition of PMMA to the (1 − x)(BMITFSI),xLiTFSI ionic liquid lowers the conductivity but might improve the lithium transference number by transforming the [Li(TFSI) 2 ] − anionic clusters present in the pure ionic liquid into a mixed coordination by ester groups and TFSI − anions.