Electrolytes with Ionic Liquids

Ionic liquids are constituted by multi-atomic organic ions, which have a low melting point, ideally much lower than room temperature thus, these salts are liquids at ambient temperatures at which batteries are required to operate. They are the solvent 

1 Lithium Metal Rechargeable Batteries in Ionic Liquids 

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Shin J-H, Henderson WA, Passerini S (2005) PEO-based polymer electrolytes with ionic liquids and their use in lithium metal-polymer electrolyte batteries. J Electrochem Soc 152(5) A978-A983. doi 10.1149/l.1890701... 

Two modifications of plasticizers are generally applied. One is to use materials that have similar structures with the plasticizers mentioned in Table 11.1. As shown in Figure 11.35, phosphate can be used as a spacer to separate EO units. The other modification uses ionic liquids as plasticizers. Inorganic plasticizers are prepared by replacing the organic plasticizers in the gel polymer electrolyte with ionic liquids. For example, in the case of P(TFE-HFP) copolymer, it is mixed with an ionic liquid. The ionic conductivity at room temperature exceeds 10 S/cm, and rises to more than 10 S/cm at 100°C. As discussed in Section 9.7, the preparation of ionic liquid is simple. 

In the first approach, PVP was used as gelling agent in electrolytes with ionic liquid. ° ° PVP was combined with HOOC(CH2) COOH (n = 4,7, 10,14), and the gelation was given by the reaction between the polymer and the dicarboxylic acid. Before gelation, the electrolyte based on the ionic liquid provided an efficiency of 5.2%.The gel electrolytes lead to solar cells with efficiencies of 3.4% to 4.4%, for carboxylic acid with different chain sizes, and the decrease in performance was associated with a decrease in the diffusion properties of the redox-active species. This decrease in... 

Abstract The chapter begins by discussing the characters and composition of polymer electrolytes for electrochromic devices. It then describes the four types of the polymer electrolytes dry solid polymer electrolyte, gel polymer electrolyte, porous gel polymer electrolyte and composite solid polymer electrolyte, their preparation procedures and properties especially ion conductivity of the samples. Finally, new types of polymer electrolytes including proton-conducting, alkaline, single ionic polymer electrolytes and electrolytes with ionic liquids are also introduced. 

Polymer electrolyte with ionic liquids N-butyl-N-methylpyrrolidiniwn bis(trifluoromethanesulphonyl) imides (PYRuTFSI)... 

Ionic liquid solvents are non-volatile and non-toxic and are liquids at ambient temperature. Originally, work was concerned with battery electrolytes. These ionic liquids (IL) show excellent extraction capabilities and allow catalysts to be used in a biphasic system for convenient recycling (Holbrey and Seddon, 1999). IFP France has commercialized a dimerization process for butenes using (LNiCH2R ) (AlCU) (where L is PRj) as an IL and here the products of the reaction are not soluble in IL and hence separate out. The catalyst is very active and gives high selectivity for the dimers. 

The plasma ionic liquid interface is interesting from both the fundamental and the practical point of view. From the more fundamental point of view, this interface allows direct reactions between free electrons from the gas phase without side reactions - once inert gases are used for the plasma generation. From the practical point of view, ionic liquids are vacuum-stable electrolytes that can favorably be used as solvents for compounds to be reduced or oxidised by plasmas. Plasma cathodic reduction may be used as a novel method for the generation of metal or semiconductor particles, if degradation reactions of the ionic liquid can be suppressed sufficiently. Plasma anodic oxidation with ionic liquids has yet to be explored. In this case the ionic liquid is cathodically polarized causing an enhanced plasma ion bombardment, that leads to secondary electron emission and fast decomposition of the ionic liquid. 

Galvanic cell (or galvanic element) — A galvanic cell is an - electrochemical cell in which reactions occur spontaneously at the -> electrodes when they are connected externally by a conductor. In these cells chemical energy can be converted into electrical energy [i, ii]. The galvanic cell consists of two electrodes, i.e., electron conductors (-> metal, carbon, semiconductor etc.) in contact with one or more ionic conductors (which may be - electrolyte solutions, ionic liquids, electrolyte melts, or - solid electrolytes). 

Carbamatosil Nanocomposites with Ionic Liquid Redox Electrolytes for Electrooptic Devices... 

Whilst conducting a series of experimental and theoretically based studies, the group of Bond highlighted the value of voltammetric measurements with microparticles attached to an electrode in contact not only with aqueous or organic electrolyte solutions but also with ionic liquids such as N,N-dimethylammonium N, N -dimethylcarbamate (DIMCARB or BMIM ). In this way, both thermodynamic and kinetic information could be obtained [81, 92-94,107,108]. Within this context, two benefits should perhaps be mentioned ... 

Many approaches have been developed for the production of ionic liquid-polymer composite membranes. For example, Doyle et al. [165] prepared RTILs/PFSA composite membranes by swelling the Nafion with ionic liquids. When 1-butyl, 3-methyl imidazolium trifluoromethane sulfonate was used as the ionic liquid, the ionic conductivity ofthe composite membrane exceeded 0.1 S cm at 180 °C. A comparison between the ionic liquid-swollen membrane and the liquid itself indicated substantial proton mobility in these composites. Fuller et al. [166] prepared ionic liquid-polymer gel electrolytes by blending hydrophilic RTILs into a poly(vinylidene fiuoridej-hexafluoropropylene copolymer [PVdF(HFP)] matrix. The gel electrolytes prepared with an ionic liquid PVdF(HFP) mass ratio of 2 1 exhibited ionic conductivities >10 Scm at room temperature, and >10 Scm at 100 °C. When Noda and Watanabe [167] investigated the in situ polymerization of vinyl monomers in the RTILs, they produced suitable vinyl monomers that provided transparent, mechanically strong and highly conductive polymer electrolyte films. As an example, a 2-hydroxyethyl methacrylate network polymer in which BPBF4 was dissolved exhibited an ionic conductivity of 10 S cm at 30 °C. 

Carbamatosil Nanocomposites with Ionic Liquid Redox Electrolytes for Electrooptic Devices...967 Jovanovski, V. Orel, B. Surca Vuk, A. 

Other electrolytes have been tested. Saccharin sodium hydrate was recently proposed by Bazzaoui et al. [91], as well as saccharin added to oxalic acid as supporting electrolyte [92]. In this latter case an improvement with respect to the oxalic acid electrolyte was attributed to a reinforcement of the barrier effect of the passive layer. Less usual ways have been explored with ionic liquids as media for electropolymerization. Formation of highly conducting PPy on iron in l-butyl-3-methylimidazolium hexafluorophosphate was reported [93] however, it does not seem promising because such solvents are expensive and also because adhesion to the metal is poor. 

FIGURE 2.58 Capacitance as a function of electrode surface curvature radius and geometry for various open structure electrode geometries as obtained from MD simulations at the 4 V potential difference between electrodes. (Reprinted with permission from Vatamanu, J. et al., 2013. Increasing energy storage in electrochemical capacitors with ionic liquid electrolytes and nanostructured carbon electrodes. Journal of Physical Chemistry Letters 4 2829-2837. Copyright 2013 American Chemical Society.)... 

Vu, A., X. Y. Li, J. Phillips et al. 2013. Three-dimensionally ordered mesoporous (3DOm) carbon materials as electrodes for electrochemical double-layer capacitors with ionic liquid electrolytes. Chemistry of Materials 25 4137-4148. 

Pandey, G. R, and S. A. Hashmi. 2013. Performance of solid-state supercapacitors with ionic liquid l-ethyl-3-methylimidazohum tris(pentafluoroethyl) trifluorophosphate based gel polymer electrolyte and modified MWCNT electrodes. Electrochimica Acta 105 333-341. 

FIGURE 18.3 Comparison of cyclic voltammograms of polypyrrole (PPy) films in classical electrolyte and ionic liquids. Scan rate 100 mVs . (Reprinted from Pringle, J.M., J. Efthimiadis, PC. Howlett, D.R. MacFarlane, A.B. Chaplin, S.B. Hall, D.L. Officer, G.G. Wallace, and M. Forsyth. Polymer, 45,1447-1453, 2004. With permission.)... 

The key to the development of solid polymer electrolytes with ionic conductivities approaching those of their liquid electrolyte counterparts (i.e. 

Zhang J, Bond AM (2005) The role of dissolntion in the voltammetry of microdroplets and microparticles adhered to electrode snrfaces in contact with aqneons electrolytes or ionic liquids. J Electroanal Chem 574(2) 299-309. doi 10.1016/J.Jelechem.2004.08.011... 

Cai Q, Xian YZ, Li H, Zhang YM, Tang J, Jin LT (2001) Studies on a sulfur dioxide electrochemical sensor with ionic liquid as electrolyte. Huadong Sfaifan Dtixue Xuebao, Ziran Kexueban 2(X)l(3) 57-60 Demus D, Goodby J, Gray GW, Spiess H-W, Vill V (eds) (1998) Handbook of liquid crystals. Wiley, Weinheim, Vol. 1, Chap. 2, pp. 18-19... 

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