Binary room-temperature complex electrolytes based on LiClO4 and organic compounds with acylamino group and its characterization for electric double layer capacitors

Wu, Feng; Chen, Renjie; Wu, Fan; Li, Li; Xu, Bin; Chen, Shi; Wang, Guoqing

doi:10.1016/j.jpowsour.2008.04.062

Cited by 18 publications

(13 citation statements)

References 25 publications

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“…[55,56] This quantity depends on the amount of charge localized on the donor and acceptor (Z A and Z D ), their diameter d and their separation R [Eq. (15)]. Note that, in contrast to electronic transport, the ions in ionic transport phenomena do not change their diameter during charge transport.…”

Section: A Modified Marcus Ansatz To Account For the Ion Dynamicsmentioning

confidence: 99%

“…[1,2] The potential of combining several of those properties in one IL makes them interest-ing for various applications, for example, as electrolytes, as polar solvents and reaction media, and for fundamental research. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] For example, an ideal IL electrolyte for (electrochemical) energy-conversion and energy-storage devices would show low viscosity, high conductivity and self-diffusion constants, a very low melting point, and a large electrochemical stability window. ILs with both anions of this study fulfill these requirements.…”

Section: Introductionmentioning

confidence: 99%

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Size Matters! On the Way to Ionic Liquid Systems without Ion Pairing

Rupp

Roznyatovskaya

Scherer

et al. 2014

Chemistry A European J

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Several, partly new, ionic liquids (ILs) containing imidazolium and ammonium cations as well as the medium-sized [NTf2 ](-) (0.230 nm(3) ; Tf=CF3 SO3 (-) ) and the large [Al(hfip)4 ](-) (0.581 nm(3) ; hfip=OC(H)(CF3 )2 ) anions were synthesized and characterized. Their temperature-dependent viscosities and conductivities between 25 and 80 °C showed typical Vogel-Fulcher-Tammann (VFT) behavior. Ion-specific self-diffusion constants were measured at room temperature by pulsed-gradient stimulated-echo (PGSTE) NMR experiments. In general, self-diffusion constants of both cations and anions in [Al(hfip)4 ](-) -based ILs were higher than in [NTf2 ](-) -based ILs. Ionicities were calculated from self-diffusion constants and measured bulk conductivities, and showed that [Al(hfip)4 ](-) -based ILs yield higher ionicities than their [NTf2 ](-) analogues, the former of which reach values of virtually 100 % in some cases.From these observations it was concluded that [Al(hfip)4 ](-) -based ILs come close to systems without any interactions, and this hypothesis is underlined with a Hirshfeld analysis. Additionally, a robust, modified Marcus theory quantitatively accounted for the differences between the two anions and yielded a minimum of the activation energy for ion movement at an anion diameter of slightly greater than 1 nm, which fits almost perfectly the size of [Al(hfip)4 ](-) . Shallow Coulomb potential wells are responsible for the high mobility of ILs with such anions.

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Section: A Modified Marcus Ansatz To Account For the Ion Dynamicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Size Matters! On the Way to Ionic Liquid Systems without Ion Pairing

Rupp

Roznyatovskaya

Scherer

et al. 2014

Chemistry A European J

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“…In this work we have shown that the interplay between solvents and ions inside a nanopore may result in very rich electrochemical behavior, adding to the already many experimental findings and recent computational insights about organic electrolytes in EDLCs. [32][33][34][35][36][37][38][39][40][41][42][43] Despite the simplicity or ideality of the model systems, the dipole moments of many organic solvents used in EDLCs actually fall right into the range we considered in this work. For example, propylene carbonate has a dipole moment of 4.9 Debye, sulfolane 4.8 Debye, γ-butyrolactone 4.27 Debye, dimethylsulfoxide (DMSO) 3.96 Debye, and acetonitrile 3.91 Debye.…”

Section: Page 11 Of 18 Nanoscalementioning

confidence: 99%

“…24 An important question is whether this behavior is generally valid given the diversity of organic electrolytes in EDLCs. [32][33][34][35][36][37][38][39][40][41][42][43] Specically, how would the solvent properties, such as the polarity, affect the capacitance dependence on the pore size? Furthermore, is there an optimal dipole moment for a given porous electrode?…”

Section: Introductionmentioning

confidence: 99%

Unusual effects of solvent polarity on capacitance for organic electrolytes in a nanoporous electrode

Jiang

2014

Nanoscale

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The interplay between ions and solvent molecules inside the nanoporous electrodes of a supercapacitor has not been well understood but could be a fertile ground for new insights into the device's performance. By tuning the dipole moment of the solvent in an organic electrolyte, we find, from classical density functional theory calculations, pronounced oscillation of capacitance with the pore size for a moderately to weakly polar solvent. A quantitative analysis of the electric-double-layer (EDL) structure indicates that the capacitance oscillation shares a similar physical origin to that of an ionic liquid electrolyte: the oscillatory behavior arises from the formation of alternating layers of counterions and coions near strongly charged surfaces. More interestingly, we find that in the large-pore region, the capacitance versus the pore size has a volcano-shaped trend; in other words, there exists a solvent dipole moment that yields a maximal capacitance. These theoretical predictions can be validated with future experiments and highlight the great potential in tuning the organic solvent to achieve optimal performance of EDL capacitors.

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“…[1][2][3][4][5][6] In particular, protic ionic liquids (PILs) consisting of combinations of Brønsted acids and bases are a new sub-class of ILs that have attracted an increasing amount of attention in many fields because of their similar properties to ILs. [7][8][9][10] The cations of PILs are normally pyridines (i.e, 2-methylpyridine), 11 imidazoliums (i.e, N-ethylimidazolium), 12,13 pyrrolidiniums (i.e, 1-alkylpyrrolidine), [14][15][16] catenarian amines (i.e, methylamine) [17][18][19][20] or cyclic amines (i.e, caprolactam) 21 and the anions are Brønsted acids (i.e, HNO 3 ), and they are produced by proton transfer from a Brønsted acid to a Brønsted base.…”

mentioning

confidence: 99%

Physicochemical Properties of New Binary Protic Ionic Liquids Based on 2-Imidazolidone and Trifluoroacetic Acid

Chen

Xiang

et al. 2011

J. Electrochem. Soc.

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We prepared a series of new binary protic ionic liquids (PILs) based on 2-imidazolidone and trifluoroacetic acid and determined their properties such as their viscosity, thermal and electrochemical properties. The results show that these PILs possess a wide liquid state temperature range, relatively good thermal stability, low viscosity and high ionic conductivity. The conductivity of the ionic liquid at a molar ratio of 3:7 was found to be 0.30 S/m and its viscosity was only 7.7 cP at room temperature. With an increase in temperature most of the samples gave better performance. The viscosity and the conductivity of the sample with a molar ratio of 5:5 was 6.1 cP and 0.32 S/m at 60 • C, respectively. Infrared spectroscopy showed that the organic molecules coordinate with the H + cation and CF 3 COO − anion through their polar groups (C=O and NH groups). These properties, therefore, result in these PILs being of interest for application in organic synthesis, especially as catalysts in acid catalytic reactions.Ionic liquids (ILs) possess several peculiar physicochemical properties such as negligible vapor pressure, high thermal stability, good solvation ability toward a wide range of catalysts and acceptable ionic conductivity, and their application in catalytic reactions, organic synthesis and electronic devices or fuel cells has been reported recently. [1][2][3][4][5][6] In particular, protic ionic liquids (PILs) consisting of combinations of Brønsted acids and bases are a new sub-class of ILs that have attracted an increasing amount of attention in many fields because of their similar properties to ILs. [7][8][9][10] The cations of PILs are normally pyridines (i.e, 2-methylpyridine), 11 imidazoliums (i.e, N-ethylimidazolium), 12, 13 pyrrolidiniums (i.e, 1-alkylpyrrolidine), 14-16 catenarian amines (i.e, methylamine) 17-20 or cyclic amines (i.e, caprolactam) 21 and the anions are Brønsted acids (i.e, HNO 3 ), and they are produced by proton transfer from a Brønsted acid to a Brønsted base. Greaves et al. 17 combined primary amine organic anions of the form RNH 3 and R(OH)NH 3 with organic anions of the form RCOO − and R(OH)COO − as well as inorganic anions to prepare a series of PILs. They found that a methylamine/HCOOH (MAF) composite had very low viscosity and high ionic conductivity. However, some problems impede the development and application of these compounds such as stability problems from condensation side reactions to form an amide during the preparation of MAF and strong water absorption of MAF. Lactams such as caprolactam and butyrolactam have been reported to react with Brønsted acids (HBF 4 , CF 3 COOH, PhCOOH, ClCH 2 COOH, HNO 3 or H 3 PO 4 ) through a simple and atom-economic neutralization reaction without a vice-reaction. Lactam-based PILs have a relatively low cost and low toxicity but their ionic conductivities are not satisfactory and are generally lower than those of primary amine-based PILs. 21 We have previously prepared acetamide-based PILs and we showed that the acylamino groups in aceta...

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Binary room-temperature complex electrolytes based on LiClO4 and organic compounds with acylamino group and its characterization for electric double layer capacitors

Cited by 18 publications

References 25 publications

Size Matters! On the Way to Ionic Liquid Systems without Ion Pairing

Size Matters! On the Way to Ionic Liquid Systems without Ion Pairing

Unusual effects of solvent polarity on capacitance for organic electrolytes in a nanoporous electrode

Physicochemical Properties of New Binary Protic Ionic Liquids Based on 2-Imidazolidone and Trifluoroacetic Acid

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