The Phenomenological Account for Electronic Polarization in Ionic Liquid

Chaban, Vitaly V.; Voroshylova, Iuliia V.; Kalugin, Oleg N.

doi:10.1149/1.3563089

Cited by 11 publications

(6 citation statements)

References 55 publications

(94 reference statements)

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“…Polarization significantly influences the Li + /MeCO 3 – binding energy as removal of polarization reduces the Li + /MeCO 3 – binding energy from −162.4 to −148.8 kcal/mol. In MD simulations with polarization turned off, the structure of the Li + coordination shell changed little, as shown in Figure , indicating that polarization has little influence on the Li + coordination shell, which is consistent with the relatively minor influence of polarization observed in RTILs. ,− This is likely due to the cancellation of the polarization contribution in the most stable configurations of the melt and crystal.…”

Section: Influence Of Many-body Polarization Of Li2edc Melt Structure...supporting

confidence: 70%

Molecular Dynamics Simulations and Experimental Study of Lithium Ion Transport in Dilithium Ethylene Dicarbonate

et al. 2013

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Understanding the properties of the solid electrolyte interphase (SEI) of lithium batteries is important for minimizing interfacial resistance and improving battery safety and cycling. Ion transport has been investigated in the dilithium ethylene dicarbonate (Li2EDC) component of the SEI by impedance spectroscopy and molecular dynamics (MD) simulations employing a revised many-body polarizable APPLE&P force field. The developed force field accurately described the binding energies in LiCH3CO3, its dimer, and Li2EDC calculated at the G4MP2 and MP2 levels. M05-2X and LC-ωPBE functionals predicted too high binding energy in lithium alkyl carbonates compared to the G4MP2 results, while the MP2 and M06-L predictions agreed well with the G4MP2 data. The conductivity of Li2EDC at room temperature was found to be 10–9 S/cm from impedance measurements and extrapolation of MD simulation results. A near Arrhenius temperature dependence of Li2EDC’s conductivity was found in the MD simulations with an activation energy ranging from 64 to 84 kJ/mol. At room temperature, the lithium transport was subdiffusive on time scales shorter than ∼10–2 s in MD simulations corresponding to the onset of the plateau of resistivity vs frequency occurring at frequencies lower than 102 Hz. The influence of Li2EDC ordering on the ion transport was investigated by contrasting supercooled amorphous melts and ordered material. At 393 K Li+ transport was heterogeneous, showing chainlike and looplike Li+ correlated displacements. The non-Gaussianity of Li+ transport was examined. The influence of polarization on the structure of the lithium coordination shell and ion transport has been investigated in the molten phase of Li2EDC and contrasted with the previous results obtained for room-temperature ionic liquids (RTILs). Nonpolarizable Li2EDC exhibited orders of magnitude slower dynamics below 600 K and a higher activation energy for the Li+ diffusion coefficient. Initial simulations of Li2EDC dissolved in an EC:DMC(3:7)/LiPF6 liquid electrolyte were performed at 450 K and showed a strong aggregation of Li2EDC consistent with its phase separation from the electrolyte. The plasticizing effects of carbonate electrolyte on Li2EDC dynamics were examined.

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Section: Influence Of Many-body Polarization Of Li2edc Melt Structure...supporting

confidence: 70%

Molecular Dynamics Simulations and Experimental Study of Lithium Ion Transport in Dilithium Ethylene Dicarbonate

et al. 2013

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“…Recently, it was demonstrated 29,44,45 that the realistic ionic transport of imidazolium-based RTILs can be simulated by means of a uniform decrease of the Coulombic interaction energy between all interaction sites of both ions. It should be noted that the neutral part of the alkyl tail, in general, does not require scaling in order to preserve the compatibility with the force fields for alkanes.…”

Section: Force Fieldsmentioning

confidence: 99%

Acetonitrile Boosts Conductivity of Imidazolium Ionic Liquids

Chaban

Voroshylova

Kalugin³

et al. 2012

J. Phys. Chem. B

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145

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We apply a new methodology in the force field generation (Phys. Chem. Chem. Phys.2011, 13, 7910) to study binary mixtures of five imidazolium-based room-temperature ionic liquids (RTILs) with acetonitrile (ACN). Each RTIL is composed of tetrafluoroborate (BF(4)) anion and dialkylimidazolium (MMIM) cations. The first alkyl group of MIM is methyl, and the other group is ethyl (EMIM), butyl (BMIM), hexyl (HMIM), octyl (OMIM), and decyl (DMIM). Upon addition of ACN, the ionic conductivity of RTILs increases by more than 50 times. It significantly exceeds an impact of most known solvents. Unexpectedly, long-tailed imidazolium cations demonstrate the sharpest conductivity boost. This finding motivates us to revisit an application of RTIL/ACN binary systems as advanced electrolyte solutions. The conductivity correlates with a composition of ion aggregates simplifying its predictability. Addition of ACN exponentially increases diffusion and decreases viscosity of the RTIL/ACN mixtures. Large amounts of ACN stabilize ion pairs, although they ruin greater ion aggregates.

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“…A number of force fields for RTILs, 19,22,[31][32][33][34][35][36][37][38][39][40][41][42] including [BMIM][BF 4 ], have been suggested during the last decade, covering a broad spectrum of species. Both empirical FFs and direct ab initio calculations of the ion pairs were extensively used to derive structure, dynamics, and energetic properties 18,19,22,31,32,[43][44][45][46][47] of pure RTILs and certain mixtures of practical interest. Borodin suggested a polarizable force field 22 employing the Thole-type approach.…”

Section: Force Fieldsmentioning

confidence: 99%

A new force field model of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and acetonitrile mixtures

Chaban

Prezhdo

2011

Phys. Chem. Chem. Phys.

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Recently, we introduced a new force field (FF) to simulate transport properties of imidazolium-based room-temperature ionic liquids (RTILs) using a solid physical background. In the present work, we apply this FF to derive thermodynamic, structure, and transport properties of the mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate, [BMIM][BF(4)], and acetonitrile (ACN) over the whole composition range. Three approaches to derive a force field are formulated based on different treatments of the ion-ion and ion-molecule Coulomb interactions: unit-charge, scaled-charge and floating-charge approaches. The simulation results are justified with the help of experimental data on specific density and shear viscosity for these mixtures. We find that a phenomenological account (particularly, a simple scaled-charge model) of electronic polarization leads to the best-performing model. Remarkably, its validity does not depend on the molar fraction of [BMIM][BF(4)] in the mixture. The derived FF is so far the first molecular model which is able to simulate all transport properties of the mixtures, comprising RTIL and ACN, fully realistically.

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The Phenomenological Account for Electronic Polarization in Ionic Liquid

Cited by 11 publications

References 55 publications

Molecular Dynamics Simulations and Experimental Study of Lithium Ion Transport in Dilithium Ethylene Dicarbonate

Molecular Dynamics Simulations and Experimental Study of Lithium Ion Transport in Dilithium Ethylene Dicarbonate

Acetonitrile Boosts Conductivity of Imidazolium Ionic Liquids

A new force field model of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and acetonitrile mixtures

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