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Amino-functionalized ionic liquids are potential and promising media for CO2 absorption, separation, and biocatalysts due to their greenness, favorable fluidity, higher positive charge density, and rich pore structure characteristics. Two new binary mixtures, {1-aminopropyl-3-methylimidazolium tetrafluoroborate ([NH2−Pmim][BF4]) + dimethyl sulfoxide (DMSO)} and {[NH2−Pmim][BF4] + acetonitrile (ACN)}, were prepared to investigate the thermodynamic properties and internal interaction behaviors. First, the thermodynamic properties such as dynamic viscosity, density, electrical conductivity, and refractive index of the two mixture systems over the entire concentration range were measured from 288.15 to 353.15 K. By the Arrhenius equation and Vogel−Fulcher−Tamman (VFT) equation, the temperature dependence on electrical conductivity was graphically described. To investigate the internal interactions of the mixtures, the excess molar volume (VE), and viscosity deviation (Δη) were calculated and discussed by using the measured experimental data and Redlich−Kister equation fitting. Further, the structures and energies of the cation, anion, ion pairs, and solvent molecules were obtained by density functional theory (DFT) calculations to evaluate the intermolecular interactions among the different components of the mixture systems. Also the σ-profile provided the relationship between hydrogen bond donor and acceptor between IL and solvents. [ABSTRACT FROM AUTHOR]

A binary mixture of ionic liquid 1-ethyl-3-methylimidazolium thiocyanate ([C2mim][SCN]) and methanol was prepared along with the whole composition range. Thermodynamic properties such as densities, dynamic viscosities, and electrical conductivities of binary system were measured from 293.15 to 323.15 K at 101.3 KPa. The electrical conductivities dependences of IL mole fraction were graphically described by the Casteel–Amis four-parameter equation. The excess molar volumes (VE) and dynamic viscosity deviations (Δη) of the binary mixture were calculated and satisfactorily fitted by the Redlich–Kister polynomial equation to reveal the interactions that exist among the components. For a deep understanding of the intermolecular interactions of the binary mixture, the infrared spectrum analysis was used to provide the observable changes related to the structural features, and the stable structures, energies of the complexes involving cation or anion of [C2mim][SCN] and methanol molecule were calculated by density functional theory calculations at B3LYP/6-311++G** level of calculation to evaluate the interaction situations of the IL and methanol. [ABSTRACT FROM AUTHOR]

The densities, dynamic viscosities, and electrical conductivities of the ionic liquid (IL) 1-ethyl-3-methylimidazolium thiocyanate ([C2mim][SCN]) and its mixtures with propylene carbonate(PC) were measured as functions of temperature over the whole composition range at atmospheric pressure. The excess molar volumes (VE) and dynamic viscosity deviations (Δη) of the mixtures were calculated and the change of VE and Δη were fitted by the Redlich–Kister (R–K) polynomial equation. The temperature dependences of dynamic viscosity and electrical conductivity of the mixture were graphically described by the Vogel–Fulcher–Tammann (VFT) equation. The Casteel–Amis four-parameter (C–A) equation was used to described the electrical conductivities dependences of IL mole fraction. To describe the intermolecular interactions of the mixtures, the optimized structures and energetics of each component of the mixture are calculated by DFT method. The hydrogen bonding between 1-ethyl-3-methylimidazolium cation([C2mim]+) and PC are enhanced, and the addition of PC can weaken the interaction between the [C2mim]+ and [SCN]−. [ABSTRACT FROM AUTHOR]

An ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) was blended with spiro-(1,10)-bipyrrolidinium tetrafluoroborate (SBPBF4) salt and propylene carbonate (PC) to obtain a liquid mixture electrolyte system. The thermodynamic properties of the mixture electrolyte with different molar compositions such as viscosity, density, and electrical conductivity were determined at different temperatures. Infrared spectroscopy and density functional theory (DFT) are used to calculate and describe the microscopic interactions in the mixture electrolyte system. Then, the IL-based mixture electrolyte was applied in supercapacitor with active carbon electrodes. The supercapacitor performances of the mixture electrolyte including the electrochemical window, the specific capacitance, and the energy density were tested and reckoned by cyclic voltammetry (CV), electrochemical impedance spectrum (EIS), and galvanostatic charge–discharge (GCD) methods, respectively. The interaction analysis and the electrochemical test results indicate that the appropriate addition of IL is a simple and effective way to improve the electrochemical performance of the electrolyte in supercapacitors. [ABSTRACT FROM AUTHOR]

In the present work, a new binary mixture system composed of the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([Emim][CF3SO3]) and propylene carbonate (PC) was prepared. The densities, dynamic viscosities, and electrical conductivities of ([Emim][CF3SO3] + PC) were measured over the whole concentration range (mole fractions of IL from 0 to 1) for temperatures from 288.15 to 353.15 K. The excess molar volumes (VE) and viscosity deviations (Δη) of the binary systems were calculated to characterize the volume contraction and intermolecular interactions in the mixture system, and both were correlated with the Redlich-Kister polynomial equation. The Vogel-Fulcher-Tamman equation was used to describe the temperature dependences of the dynamic viscosities and the electrical conductivities of the binary system. Further, density functional theory calculations were employed to obtain the structure, energy, and COSMO charge distributions of the cation and anion of the IL and the PC molecule, and the intermolecular interactions in the binary mixture system were evaluated. [ABSTRACT FROM AUTHOR]

Abstract In this study, two novel binary systems of ionic liquids (ILs) {1-cyanopropyl-3-methyl-imidazolium bis(fluorosulfonyl)imide ([C 3 CNmim][FSI]), or 1-cyanopropyl-3-methyl-imidazolium trifluoromethanesulfonate ([C 3 CNmim][CF 3 SO 3 ]) + acetonitrile (AN)} are prepared over the whole concentration. Densities (ρ), electrical conductivities (σ), dynamic viscosities (η), and surface tensions (γ) of pure ILs and two binary systems were measured at temperatures from 288.15 to 323.15 K at 101 kPa within the whole composition range. The thermodynamic parameters of pure ILs such as coefficient of thermal expansion (α), standard molar entropy (S 0), and lattice energy (U POT) were estimated. The excess molar volumes (V E) were obtained from the experimental densities and fitted to Redlich–Kister (R–K) polynomial equation. The dependence of the transport properties (viscosity and conductivity) on temperature can be described by the Vogel–Fulcher–Tamman (VFT) equation. In order to obtain information about interactions between AN molecules and selected ILs, the density functional theory (DFT) calculations combining the COSMO–RS methodology were employed. The hydrogen bonds formation between components of the mixtures was discussed from the calculation results and the variations in the infrared (IR) spectrum. Highlights • Two novel binary systems were prepared and the physicochemical properties were measured. • Excess properties were estimated to discuss intermolecular interactions. • The density functional theory calculations were employed. • The infrared spectrum comparisons were used to describe intermolecular interactions. [ABSTRACT FROM AUTHOR]

The densities, dynamic viscosities, and electrical conductivities of the ionic liquid (IL) N-butyl-pyridinium dicyanamide ([C 4 py][DCA]) and its binary system with propylene carbonate (PC) were measured at the temperature range from 288.15 to 353.15 K over the whole composition range at atmospheric pressure. In addition, some significant thermodynamic parameters were also estimated. The excess molar volumes ( V E ) and dynamic viscosity deviations ( Δη ) of the mixtures were calculated, and the change of V E and Δη were fitted by the Redlich–Kister (R–K) polynomial equation. The temperature dependences of dynamic viscosities and electrical conductivities of the binary system under the whole concentration range (molar ratio of IL from 1 to 0) were graphically described by the Vogel–Fulcher–Tamman (VFT) equation and Arrhenius equation. Through the Walden rule, the ionicity of binary system at each concentration was evaluated as a function of the temperature from 288.15 to 353.15 K. Further, according to three-electrode method, the electrochemical potential windows (EPWs) of binary system ( x IL = 1.0000, 0.7885, 0.4997, 0.1003) were measured to investigate the electrochemistry stability. In a supercapacitor, the IL mixtures of two molar ratios ( x IL = 1.0000, 0.7885) were applied as electrolytes, and the performance of the supercapacitors were determined by cyclic voltammetry (CV) method. [ABSTRACT FROM AUTHOR]

A new binary mixture system of ionic liquid 1–ethyl–3–methylimidazolium acetate ([Emim][Ac]) and methyldiethanolamine (MDEA) (IL + alkanolamine) were prepared. The physico–chemical properties of density, viscosity, electrical conductivity, and refractive index for the mixtures were determined from 288.15 K to 353.15 K. By the Vogel–Fulcher–Tamman (VFT) equation and Arrhenius equation, the temperature dependences of the viscosities and electric conductivities for the system were graphically described and the VFT equation showed better correlation for the system. To investigate the internal interactions of the mixtures, the excess volume and DFT calculations were employed. The trend of excess molar volumes showed more efficient packing structures due to the increase of interactions in the mixed system with the increasing of temperature. Further, the structures, the energetics, and charge distribution of all ions and molecules involved in interactions were estimated by DFT calculations combining the COSMO–RS methodology to describe intermolecular interactions between the [Emim][Ac] and MDEA. [ABSTRACT FROM AUTHOR]

A series of 1-alkyl-3-methylimidazolium thiocyanate [C nmim][SCN] ( n = 2-5) ionic liquids (ILs) with low dynamic viscosity were synthesized by a two-step method and characterized by IR and 1H NMR spectroscopy. The physicochemical properties of the ILs such as density, surface tension, dynamic viscosity, and electrical conductivity were measured. The significant thermodynamic parameters of the ILs such as molecular volume, standard molar entropy, lattice energy, parachor, interstice parameters, and thermal expansion coefficient were estimated according to semi-empirical/empirical methods. Subsequently, the viscosity and electrical conductivity characteristics of the [C2-5mim][SCN] were described by the Vogel-Fulcher-Tamman (VFT) equation. The results showed that the VFT equation was a proper fit for the ILs. Moreover, the transport properties of ILs were discussed based on the Walden rule and the relationships between molar conductivities and dynamic viscosities were evaluated. [ABSTRACT FROM AUTHOR]

A carbon nanoparticle ionic liquid (CNPIL) as a conductive agent and binder is introduced into an activated carbon electrode to improve supercapacitor performance. It has a high specific capacitance of 223 F g−1, high power density (1.64 kW kg−1 at 83.2 W h kg−1) and high charge–discharge efficiency (97.3%). [ABSTRACT FROM AUTHOR]

Two novel ionic-liquid-based binary mixture systems of N,N-diethyl-N-(2-methoxyethyl)- N -methylammonium tetrafluoroborate ([DEME][BF 4), or N,N-diethyl- N -methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl)imide ([DEME][TFSI]) + γ-butyrolactone (GBL) are prepared over the whole concentration range (mole fraction from 0–1). Some important thermodynamic properties and parameters of the pure ILs and two systems were measured and calculated. The temperature dependences of the transport properties (viscosity and conductivity) were described by the Vogel–Fulcher–Tamman (VFT) equation. The excess molar volumes (V E) were obtained from the experimental densities and fitted to Redlich–Kister (R–K) polynomial equation. The DSC analysis, the shifts of the infrared (IR) spectrum, and COSMO–RS methodology based on DFT calculations were combined to explain the interaction information of GBL molecules and cations/anions of the selected systems. The stable optimized structures, interaction energies, and charge distributions were further obtained. Those maybe slight enlighten the application of similar mixture systems in future. • Two new binary systems ([DEME][BF 4 + GBL and [DEME][TFSI] + GBL were prepared and the physicochemical properties were measured. • Volumetric properties between [DEME][BF 4 or [DEME][TFSI] and GBL were investigated. • Spectroscopy (FT-IR) and Differential Scanning Calorimeter (DSC) technique were used to discuss the molecular interactions. • The intermolecular interactions were evaluated by DFT calculations. [ABSTRACT FROM AUTHOR]

• Two ether-functionalized ILs mixture systems were prepared and their thermodynamic properties were measured. • The excess molar volume and viscosity deviation were calculated and provided a microscopic information on the interactions. • DFT calculation found that C2–H of the cation exhibited the capability to form H-bonds with anion and solvents. • The molecular dynamics simulations presented a more robust H-bonds interaction between [MOEmim][TFSI] and GBL compared to ACN. Ether-functionalized ionic liquids (ILs) have a higher fluidity and are widely used in a variety of applications due to the introduction of the ether group. In order to better understand the relationship between properties and internal interactions of ether-based ILs, we prepared two ether-functionalized ILs 1–2-methoxyethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([MOEmim][TFSI]) with acetonitrile (ACN) or γ -butyrolactone (GBL) mixture systems, and investigated the changes of their thermodynamic properties and internal interaction behaviors over the entire concentration range. First, the thermodynamic properties such as dynamic viscosity, density and electrical conductivity of the two mixture systems were measured from 288.15 K to 343.15 K. The excess molar volume (V E), and viscosity deviation (Δ η) were calculated by using the measured experimental density and dynamic viscosity data, which can provide microscopic information on the interactions. Further, the intermolecular interactions of the mixture systems were evaluated by density functional theory (DFT) calculations. The sigma–profile (σ –profile) provided insight into the hydrogen bonds (H-bonds) and molecular surfaces interactions. We also used molecular dynamics simulations (MD) to study ILs mixtures in many different solvent concentrations, thereby providing a microscopic and macroscopic characterization of fluid structure, molecular aggregation, and intermolecular forces. [ABSTRACT FROM AUTHOR]

Ionogel electrolytes (IGEs) with chemical and thermal stability properties have attracted considerable attention for all-solid-state energy storage devices, particularly for high-performance supercapacitors (SCs). However, achieving high conductivity, flexibility, and toughness, as well as deformation and impact resistance in special cases, is challenging with the typical polymer based on ionic liquids (ILs). Here, an effective gelation strategy is proposed for the preparation of free-standing LiTFSI/[EMIM][TFSI]/PVDF-HFP ionogels (IGs) by double-additive induced physical cross-linking. The mechanical and electrochemical properties of the IGs can be synergistically optimized by the cross-linking and entanglement of LiTFSI and [EMIM][TFSI] with the PVDF-HFP network. The target IGs simultaneously exhibit excellent deformation capacity (over 50 %), high ionic conductivity (10.3 × 10−3 S cm−1 at 25 °C), hardness (H: 728.6 kPa), and Young's modulus (E: 11.4 MPa), which can exhibit the specific capacitance of 274. 55 F g−1, energy density of 38.13 Wh kg−1 and maximum power density of 2499.93 W kg−1 in the fabricated symmetric supercapacitor. The results will motivate us to further explore their applications for flexible electronic devices, wearable electronic skin, and flexible energy storage. [Display omitted] • The IGE has excellent mechanical strength and deformation ability. • The IGE with high ionic conductivity of 10.5 × 10−3 S cm−1. • The supercapacitor provides higher specific capacitance, energy and power density. • The change of ionic conductivity was verified by molecular dynamics simulation. [ABSTRACT FROM AUTHOR]

Highlights • The binary mixtures of [C 2 mmim][NTf 2 ]/[C 4 mmim][NTf 2 ] + DMC/DEC were prepared. • The density and dynamic viscosity of the binary mixtures were measured. • The excess molar volumes and viscosity deviations were calculated. • The properties were discussed with the extension of the alkyl chain of the cation. Abstract Two hydrophobic ionic liquids (ILs) 1-alkyl-2, 3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C 2 mmim][NTf 2 ] and [C 4 mmim][NTf 2 ]) were synthesized. The binary mixtures of the two ILs were prepared with dimethyl carbonate (DMC) or diethyl carbonate (DEC) over the entire mole fraction range, respectively. The density and viscosity of the binary mixtures were investigated at temperature ranging from 293.15 to 328.15 K. The excess molar volumes and viscosity deviations were calculated for the four binary mixtures. The effects of the extension of the alkyl chain of the cation on the above properties are discussed. The Redlich-Kister equation was used for the fitting of the excess molar volumes and viscosity deviations versus mole fraction. The thermal expansion coefficients of the systems were obtained according to the density. [ABSTRACT FROM AUTHOR]

Gel-polymer electrolytes (GPEs) are of great interest to build high-performing rechargeable electrical double-layer capacitors (EDLCs) owing to the combination of good electrochemical properties and improved safety. Herein, we report a quasi-solid-state GPE for EDLCs from a mixture of the poly (vinylidene fluoride- co -hexafluoro propylene) (PVDF-HFP) and ionic liquid 1-ethyl-3-methylimidazole tetrafluoroborate ([EMIM][BF 4 ]), which avoids the leakage of liquid electrolyte and the low conductivity of common solid electrolyte. The intermolecular forces of GPE was characterized by in-situ infrared (IR) spectroscopy, and the interactions between ionic liquid and polymer were also analyzed. The prepared GPE was observed to be easily procurable, excellent transparency, high thermal safety (thermal stability up to 320 °C) and outstanding electrochemical properties at room temperature (wide electrochemical stability window of 3.91 V versus SS (SS being stainless steel foils) and high ionic conductivity of 6.9 × 10−3 S cm−1). The specific capacitance, the maximum specific energy, and the maximum specific power of the fabricated symmetrical supercapacitor had been determined to be 161.8 F g−1, 89.89 Wh kg−1, and 8 kW kg−1, respectively. Moreover, the EDLC shows extraordinary electrochemical behaviors and cyclic stability over up to 10 000 cycles at 25 °C with 86% capacitance retention under a current load of 2 A g−1. The experimental results indicate the excellent potential of the [EMIM][BF 4 ] ionic-liquid-based gel polymer electrolyte for EDLCs. [Display omitted] • The GPE has outstanding ionic conductivity and high thermal safety (up to 320 °C). • IL promotes the formation of molecular forces in the GPE by in-situ FT-IR and DFT. • The EDLC offers higher specific capacitance, specific energy and specific power. [ABSTRACT FROM AUTHOR]

• Two nitrile-functionalized ionic liquids mixture systems with γ–butyrolactone were prepared. • The densities and conductivities of two mixture systems were measured. • The excess molar volumes (V E) and apparent molar volumes (V ϕ), were calculated from the density data. • The behaviors of intermolecular interactions were explained by the volumetric properties changes, DSC analysis, IR spectrum shifts, and DFT calculations. Two functionalized ionic liquids, 1-cyanopropyl-3-methylimidazolium bistrifluoromethanesulfonimide ([C 3 CNmim][TFSI]) and 1-cyanopropyl-3-methylimidazolium trifluoromethanesulfonate ([C 3 CNmim][OTF]) were blended with γ-butyrolactone (GBL) under the full concentration range (molar fraction from 0 to 1) to form mixture systems, respectively. The densities and conductivities of pure ILs and their mixture systems were measured in the temperature range 288.15–343.15 K under normal pressure. The Vogel–Fulcher–Tammann (VFT) equation is employed to investigate the temperature dependence of conductivity. The volumetric properties of the mixture systems, excess molar volumes (V E) and apparent molar volumes (V ϕ), were calculated from the density data. The Redlich–Kister (R–K) polynomial equation and Redlich–Rosenfeld–Meyer (RRM) equation were used for the fittings of the V E and V ϕ , respectively. Further, the behaviors of intermolecular interactions in the mixture systems were explained by a combined analysis method composing of the assessment of the volumetric properties changes, the differential scanning calorimetry (DSC) analysis, the infrared (IR) spectrum shifts, and COSMO-RS methodology based on density functional theory (DFT) calculations. The stable optimized structures, H-bonding information, interaction energies, and charge distributions were consequently obtained. It can be found that the addition of the GBL weakened the hydrogen bonding interactions between the IL cations and anions. The [C 3 CNmim][TFSI] + GBL mixture system shows the lowest energy difference and it may give strong ion-solvent interactions when compare to [C 3 CNmim][OTF] mixture system. [ABSTRACT FROM AUTHOR]

Abstract: A fluorescent carbon nanoparticle ionic liquid hybrids (CNPIL) with high conductivity is synthesized by a facile one-step microwave method from ionic liquid 1-butyl-3-methylimidazolium glutamine salt and Glucose. This CNPIL exhibits excellent PL properties: bright and colorful PL covering the entire visible–NIR spectral range, up conversion PL properties, pH dependent and can be controlled by the reaction condition. [Copyright &y& Elsevier]