Ionic liquid electrolytes

Yuan LX, Feng JK, Ai XP, Cao YL, Chen SL, Yang HX (2006) Improved dischargeability and reversibility of sulfur cathode in a novel ionic liquid electrolyte. Electrochem Common 8 610-614... 

Solid polymer and gel polymer electrolytes could be viewed as the special variation of the solution-type electrolyte. In the former, the solvents are polar macromolecules that dissolve salts, while, in the latter, only a small portion of high polymer is employed as the mechanical matrix, which is either soaked with or swollen by essentially the same liquid electrolytes. One exception exists molten salt (ionic liquid) electrolytes where no solvent is present and the dissociation of opposite ions is solely achieved by the thermal disintegration of the salt lattice (melting). Polymer electrolyte will be reviewed in section 8 ( Novel Electrolyte Systems ), although lithium ion technology based on gel polymer electrolytes has in fact entered the market and accounted for 4% of lithium ion cells manufactured in 2000. On the other hand, ionic liquid electrolytes will be omitted, due to both the limited literature concerning this topic and the fact that the application of ionic liquid electrolytes in lithium ion devices remains dubious. Since most of the ionic liquid systems are still in a supercooled state at ambient temperature, it is unlikely that the metastable liquid state could be maintained in an actual electrochemical device, wherein electrode materials would serve as effective nucleation sites for crystallization. 

Hewlett, P. C., Brack, N., Hollenkamp, A. E, Forsyth, M., and MacFarlane, D. R., Characterization of the lithium surface in N-methyl-N-alkylpyrrolidinium bis(trifluoromethanesulfonyl)imide room-temperature ionic liquid electrolytes, /. Electrochem. Soc., 153, A595-A606,2006. 

Matsumoto, K., Hagiwara, R., and Tamada, O., Coordination environment around the lithium cation in solid Li2(EMlm)(N(S02CF3)2)3 (EMlm = 1-ethyl-3-methylimidazolium) Structural clue of ionic liquid electrolytes for lithium batteries. Solid State Sci., 8,1103-1107, 2006. 

Two devices are prepared. In the case of the device A, the incident photon-to-collected electron conversion efficiency (IPCE) exceeds 80% from 410 to 590 nm, reaching the maximum of 93% at 530 nm. The short-circuit photocurrent density (/sc), open-circuit photovoltage (Voc), and fill factor (FF) of device A with an acetonitrile-based electrolyte under an irradiance of AM 1.5 G full sunlight are 14.33 mA cm-12, 734 mV, and 0.76, respectively, yielding an overall conversion efficiency (jf) of 8.0%. The photovoltaic parameters of device B with a solvent-free ionic liquid electrolyte are 14.06 mA cm 12, 676 mV, 0.74, and 7.0%, respectively. 

Baranchugov V, Markevich E, Poliak E, Salitra G, Aurbach D. Amorphous silicon thin films as a high capacity anodes for Li-ion batteries in ionic liquid electrolytes. Electrochem Commun 2007 9 796-800. 

When used in electropolishing and electropickling processes, strongly acidic aqueous electrolytes create large quantities of metal-laden, corrosive effluent solution, whereas in ionic liquid electrolytes the metals will precipitate and be readily separated and recycled. 

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). 

Ishikawa M, Sugimoto T, Kikuta M, et al. Pure ionic liquid electrolytes compatible with a graphitized carbon negative electrode in rechargeable lithium-ion batteries. J. Power Sources. 2006. 162, 658-662. 

Peng C X, Yang L, Zhang Z X, et al. Investigation of the anodic behavior of Al current collector in room temperature ionic liquid electrolytes. Electrochim. Acta. 2008. 53, 4764-4772. 

Trombetta E, de Souza MO, de Souza RE et al (2009) Electrochemical behavior of aluminum in l-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid electrolytes for capacitor applications. J Appl Electrochem 39 2315-2321... 

Zheng H, Jiang K, Abe T, Ogumi Z (2006) Electrochemical intercalation of lithium into a natural graphite anode in quaternary ammonium-based ionic liquid electrolyte. Carbon 44 203-208... 

Xu J, Yang J, NuLi Y et al (2006) Additive-containing ionic liquid electrolytes for secondary lithium battery. J Power Sources 160 621-628... 

Shivagan DD, Dale PJ, SamantiHeke AP et al (2007) Electrodeposition of chalcopyrite films from ionic liquid electrolytes. Thin Solid Films 515 5899-5905... 

The use of ionic liquid electrolytes has been shown to influence electrochemical switching potentials.44 However, even more significant with the use of ionic liquid electrolytes is the ability to greatly expand the electrochemical potential window within which conducting polymers retain their physical and mechanical properties.45,46... 

Ionic liquid electrolytes have recently been used for the electrosynthesis of PAn.37 The rate of polymerization of aniline was found to be high, and adhesion of the conducting polymer product to the metal electrode was enhanced. 

D. Zhou, G.M. Spinks, G.G. Wallace, C. Tiyapiboonchaiya, D.R. MacFarlane, M. Forsyth, and J. Sun, Solid state actuators based on polypyrrole and polymer-in-ionic liquid electrolytes, Electrochim. Acta, 48 (14-16), 2355-2359 (2003). 

Lu, W., Henry, K., Turchi, C., Pellegrino, J., 2008. Incorporating ionic liquid electrolytes into polymer gels for solid-state ultracapacitors. J. Electrochem. Soc. 155, A361-A367. 

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.)... 

FIGURE 2.70 Cyclic voltammograms for [EMIMllBFJ at 5 mV s" . (Sillars, F. B. et al. 2012. Variation of electrochemical capacitor performance with room temperature ionic liquid electrolyte viscosity and ion size. Physical Chemistry Chemical Physics 14 6094-6100. Reproduced by permission of The Royal Society of Chemistry.)... 

Tsai, W. Y, R. Lin, S. Murali et al. 2013. Outstanding performance of activated graphene based supercapacitors in ionic liquid electrolyte from -50°C to 80°C. Nano Energy 2 403-411. 

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. 

Zhong, H., F. Xu, Z. Li, R. Fu, and D. Wu. 2013. High-energy supercapacitors based on hierarchical porous carbon with an ultrahigh ion-accessible surface area in ionic liquid electrolytes. Nanoscale 5 4678-4682. 

Lewandowski, A., A. Olejniczak, M. Galinski, and I. Stepniak. 2010. Performance of carbon—carbon supercapacitors based on organic, aqueous and ionic liquid electrolytes. Journal of Power Sources 195 5814-5819. 

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