Room temperature ionic liquid

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Mixtures of room temperature ionic liquid/ethanol solutions as electrolytic media for cerium oxide thin layer electrodeposition

Mixtures of room temperature ionic liquid/ethanol solutions as electrolytic media for cerium oxide thin layer electrodeposition

Abstract A cerium oxide thin layer was electrodeposited onto stainless steel, using mixed room temperature ionic liquid (the 1-methyl-3-butylimidazolium bis(trifluoromethyl sulfonyl)imide)/ethanol solutions, as electrolytic medium. The hydrophobic ionic liquid content is one of the main parameter in the morphology control influencing the ceria growth rate and crystallinity. Micro-nano structural properties and electrical behaviour are presented, using XRD, SEM/EDS and impedance spectroscopy, as a function of electrodeposition conditions.
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Room Temperature Ionic Liquid Electrolytes Based on Azepanium Imide Salts for Lithium Batteries

Room Temperature Ionic Liquid Electrolytes Based on Azepanium Imide Salts for Lithium Batteries

is 99%. Conclusions Ionic liquids based on a new family of imide salts of the ringed ammonium cation Azepanium were synthesized, characterized and tested in lithium batteries. It was found that variation in the molecu- lar structure of the cation gave three room temperature ionic liquids out of the nine salts synthesized. The highly-asymmetric ionic liqiuds were highly viscous and showed good conductivities. The electro- chemical study of the liquids showed low cathodic stability but a wide electrochemical window over 6 volts. The use of ethylene carbonate as a co-solvent led to enhancement in the physical and electrochem- cial properties of the formulated electolytes. An electrolyte based on the ionic liquid with the best thermal and electrochemical proper- ties, AZ14-TFSI, and the co-solvent was successfully used to cycle Li/Li 4 Ti 5 O 12 and Li/LiFePO 4 half cell batteries gave high and sta-
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Outstanding room-temperature capacitance of biomass-derived microporous carbons in ionic liquid electrolyte

Outstanding room-temperature capacitance of biomass-derived microporous carbons in ionic liquid electrolyte

A remarkable capacitance of 180 F·g − 1 (at 5 mV·s − 1 ) in solvent-free room-temperature ionic liquid electrolyte, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, was achieved in symmetric supercapacitors using microporous carbons with a specific surface area of ca. 2000 m 2 ·g − 1 calculated from gas sorption by the 2D-NLDFT method. The efficient capacitive charge storage was ascribed to textural properties: unlike most activated carbons, high specific surface area was made accessible to the bulky ions of the ionic liquid electrolyte thanks to micropores (1–2 nm) enabled by fine-tuning chemical activation. From the industrial perspective, a high volumetric capacitance of ca. 80 F·cm − 3 was reached in neat ionic liquid due to the absence of mesopores.
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Outstanding room-temperature capacitance of biomass-derived microporous carbons in ionic liquid electrolyte

Outstanding room-temperature capacitance of biomass-derived microporous carbons in ionic liquid electrolyte

A remarkable capacitance of 180 F·g − 1 (at 5 mV·s − 1 ) in solvent-free room-temperature ionic liquid electrolyte, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, was achieved in symmetric supercapacitors using microporous carbons with a specific surface area of ca. 2000 m 2 ·g − 1 calculated from gas sorption by the 2D-NLDFT method. The efficient capacitive charge storage was ascribed to textural properties: unlike most activated carbons, high specific surface area was made accessible to the bulky ions of the ionic liquid electrolyte thanks to micropores (1–2 nm) enabled by fine-tuning chemical activation. From the industrial perspective, a high volumetric capacitance of ca. 80 F·cm − 3 was reached in neat ionic liquid due to the absence of mesopores.
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CO₂ capture using alkanolamine/room-temperature ionic liquid blends : absorption, regeneration, and corrosion aspects

CO₂ capture using alkanolamine/room-temperature ionic liquid blends : absorption, regeneration, and corrosion aspects

30 spite of numerous studies on CO 2 solubility and its selectivity, systems mimicking industrial effluents, where the presence of water or other foreign molecules can affect CO 2 transfer, yet requires in depth investigations before industrial-scale implementation of ionic liquids is sought. Selection of an appropriate combination of the constituent ion pair (cation + anion) of ionic liquids, particularly in the context of viscosity and gas absorption kinetics, needs to be further scrutinized. Aspects related to the gas capture at higher temperatures and higher pressures, and subsequent regeneration without any appreciable loss and/or degradation as well as toxicological concerns call for intense analysis to take advantage of long-lasting cyclic use of IL-based scrubbers. An appropriate balance between cost and performance is crucial in order for these approaches to take any helm as commercially viable CO 2 capture technologies.
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Sn-based alloys synthesized in an ionic liquid at room temperature : Cu6Sn5 as a case study

Sn-based alloys synthesized in an ionic liquid at room temperature : Cu6Sn5 as a case study

this method is its ability to probe in a single experiment, molecular and ionic dynamical processes occurring on much different time scales. 20,[19],24,25 The relaxation dispersion profiles (relaxation rates plotted versus the resonance frequency) reveal specific effects (not observed in “classical” NMR relaxation studies) that can be treated as a fingerprint of the slowing down of ionic dynamics due to interaction with surfaces. Here, we used an original approach as the experiments were performed at the frozen state and exploit the modification of the 14 N nuclear energy
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Charge Storage Mechanisms of Single-Layer Graphene in Ionic Liquid

Charge Storage Mechanisms of Single-Layer Graphene in Ionic Liquid

1 d) is around 0.8 nm for SLG; the observed ripples can be ascribed to the wrinkles of graphene made by chemical vapor deposition (CVD). To examine the electrochemical properties of SLG, electro- chemical impedance spectroscopy (EIS) measurements in 1- ethyl-3-methylimidazolium bis(tri fluoromethanesulfonyl)imide (EMI-TFSI), which is a widely used room-temperature ionic liquid (RTIL) electrolyte in supercapacitors, were carried out at di fferent constant potentials. The real C′(ω) and imaginary C ″(ω) parts of the capacitance were extracted from Nyquist plots ( Figures S2 and S3 ), in which C ′(ω) corresponds to the EDL capacitance (C EDL ), while C ″(ω) accounts for dissipative processes. 24 Figure 2 a shows the typical tendency of C ′(ω) with the frequency at a bias potential of +0.2 V/ref for SLG. As expected, C ′(ω) increases when the frequency decreases, and then becomes less frequency dependent below the knee frequency at around 200 and 1 Hz, respectively. However, capacitance saturation was not observed even at 0.1 Hz, especially for high-potential polarization ( Figure S4 ) partially because of the leakage current ( ∼0.05 μA, Figure S5 ) from side reactions. C ″(ω) goes through two maxima at characteristic frequencies f 0 of 610 and 2.5 Hz, corresponding to a time constant ( τ 0 = 1/f 0 ) of 1.6 and 395 ms, respectively. 25 Comparably, the quartz substrate without SLG coating only shows one peak in C ″(ω) at 413 Hz. As a result, the SLG and exposed Au current collector are in parallel to contribute to the total capacitance in this system. The relaxation response at low frequency (2.5 Hz) is assumed to correspond to the double- layer charging process on SLG alone, which is comparable to that of reported graphene nanosheet, highly curved gra- phene. 5 , 26 Furthermore, f 0 shifts to a lower value (correspond- ing to a τ 0 of 870 ms) at more negative polarization ( Figure
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Graphene-Based Supercapacitors Using Eutectic Ionic Liquid Mixture Electrolyte

Graphene-Based Supercapacitors Using Eutectic Ionic Liquid Mixture Electrolyte

A B S T R A C T Compact graphene films were prepared and electrochemically tested at various temperatures in a eutectic of ionic liquid mixture (1:1 by weight or mole N-methyl-N-propylpiperidinium bis (fluorosulfonyl)imide and N-butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide) electrolyte. A large temperature window from -30 ! C to 80 ! C was achieved together with a large potential window of 3.5 V at room temperature and below. A maximum gravimetric capacitance of 175 F.g "1 (85 mAh.g "1 ) was obtained at 80 ! C. 130 F.g "1 (63 mAh.g "1 ) and 100 F.g "1 (49 mAh.g "1 ) were still delivered at -20 ! C and -30 ! C respectively. Besides, a volumetric capacitance of 50 F.cm "3 was achieved with a thick graphene film (60 m m). The outstanding performance of such compact graphene film in the eutectic ionic liquid mixture electrolyte makes it a promising alternative to activated carbon for supercapacitor applications, especially under extreme temperature conditions.
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Electrodeposition Growth of Oriented ZnO Deposits in Ionic Liquid Media

Electrodeposition Growth of Oriented ZnO Deposits in Ionic Liquid Media

Room temperature Ionic Liquids (RTIL) possess many attractive chemical/physical properties. They are non-flammable, display very high thermal stability together with negligible vapor pressure and are good solvents for numerous salts and polymers. 1 , 2 Such properties are at the origin of their wide use in many research fields with an ongoing increasing interest in the synthesis of inorganic materials; such a synthesis involving either ionothermal 3 or electrodeposition. 4 Moreover by changing the nature of the cations and anions, ILs can be designed for specific applications. 5 Owing to their relatively high ion conductivity, (0.2  −1 · cm −1 ) together with their high thermal and electrochemical stability (electrochemical window up to 4–5 V are reported), they stand as an alternative promising medium to wa- ter in the field of electrochemistry. 4 Such attractive characteristics have so far been widely exploited for the electrodeposition of metals and semiconductors 4 , 6 – 9 and very recently for binary compounds like CuS. 10 Additionally, control over the morphology and structure of the deposit can be achieved via tuning of the deposition conditions (temperature, wide potential window, changing cations and anions of IL, additives, mixtures of solvents, etc. 4 , 6 – 10 ). Last, the specific inter- actions of IL with the electrode surface upon applied potential (which have been recently studied by a few groups) and the deposit itself may provide additional new possibilities to adjust/orient nucleation-growth mechanisms. 11 – 15
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Capacitance of Ti3C2Tx MXene in ionic liquid electrolyte

Capacitance of Ti3C2Tx MXene in ionic liquid electrolyte

henceforth be referred to as ionogel film. 2.3. Electrochemical tests Ti 3 C 2 T x disc films were punched (with a diameter of 10 mm) after vacuum drying from both samples and used as electrodes directly without any binders. 1-ethyl-3-methylimidazolium bis- (trifluoromethylsulfonyl)-imide (EMI-TFSI) neat ionic liquid was used as the electrolyte. Two layers of separator (Celgard @ 3501) were used together with platinum discs as current collectors. Two- electrode Swagelok symmetric cells were assembled and tested at room temperature by using a VMP3 potentiostat (Biologic, USA.). All supercapacitors were assembled in a glove box under argon atmosphere with water and oxygen contents less than 1 ppm.
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Capacitance of Ti3C2Tx MXene in ionic liquid electrolyte

Capacitance of Ti3C2Tx MXene in ionic liquid electrolyte

henceforth be referred to as ionogel film. 2.3. Electrochemical tests Ti 3 C 2 T x disc films were punched (with a diameter of 10 mm) after vacuum drying from both samples and used as electrodes directly without any binders. 1-ethyl-3-methylimidazolium bis- (trifluoromethylsulfonyl)-imide (EMI-TFSI) neat ionic liquid was used as the electrolyte. Two layers of separator (Celgard @ 3501) were used together with platinum discs as current collectors. Two- electrode Swagelok symmetric cells were assembled and tested at room temperature by using a VMP3 potentiostat (Biologic, USA.). All supercapacitors were assembled in a glove box under argon atmosphere with water and oxygen contents less than 1 ppm.
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Synthesis of novel room temperature chiral ionic liquids. application as reaction media for the heck arylation of aza-endocyclic acrylates

Synthesis of novel room temperature chiral ionic liquids. application as reaction media for the heck arylation of aza-endocyclic acrylates

of the imidazolium 20 revealed that the H-2 proton had become highly exchangeable with deuterium, thus indicating an increased acidity. All these salts are liquid at room temperature and differential scanning calorimetry (DSC) analyses were recorded in order to characterize the thermal behaviour of these new chiral ionic liquids. In sharp contrast with its hexafluorophosphate counterpart (mp 86-87 °C), the imidazolinium bis(trifluoromethanesulfonyl)imide 13 displayed glass transition (Tg) at –59 °C. A comparable Tg of –57 °C was found for the corresponding n-pentyl imidazolium salt 18. This behaviour parallels, yet to a lesser extent, what we previously observed in the C-2-substituted series in which the aromatic imidazolium salts displayed Tg values 7 to 11 °C higher than the corresponding imidazolinium derivatives. Overall, the lack of substituent at C-2 lowered the Tg values which were of –55 °C and –48 °C for the corresponding 2-ethyl derivatives. Finally the side chain was also found to exert a certain influence on the thermal behaviour of these salts since a slightly higher Tg of –50 °C was observed for the methyl imidazolium bis(trifluoromethanesulfonyl)imide 19, whereas the nitrile substituted derivative 20 displayed a glass transition at –46 °C.
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Tentative of determination of the acidity level in room temperature ionic liquids  by electrochemical methods

Tentative of determination of the acidity level in room temperature ionic liquids by electrochemical methods

2 potential, the higher is also the acidity level (then the proton activity). In this paper, we will present the results obtained from electrochemical measurements on ionic liquids to which a given amount of strong acid (HOTf and HNTf 2 ) has been added. Since the liquid containing protons exhibits a reduction wave, dynamic electrochemical methods (cyclic and differential pulse voltammetry) were first tested with the purpose of measuring the location of the reduction wave versus that of ferricinium in the same solution. These methods failed for two reasons: 1) in agreement with Silvester et al, 11 the reduction process is not reversible on a polished platinum electrode and we found that the irreversibility increases drastically with the proton content. 2) since the medium is not buffered, the reduction process consumes locally the protons and the diffusion layer is then depleted, resulting in a variation of the local acidity. As a consequence, we think that only equilibrium measurements should be used, i. e. potentiometric measurements at zero current.
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Probing the local structure of pure ionic liquid salts with solid- and liquid-state NMR

Probing the local structure of pure ionic liquid salts with solid- and liquid-state NMR

Ionic liquids (ILs) have been known for nearly a century [1] but initially there was little interest in investigating their use as sol- vents. The term “room-temperature ionic liquids” (RTILs) is often used interchangeably with “ionic liquids” and is loosely defined as those ILs that have melting points at around or below 100 8C. Their low volatility has made them attractive tar- gets as substitutes for volatile organic solvents. A broad spec- trum of tunable properties arises from the customizability of the organic cation and the variety of cation–anion pairings and so ILs are often denoted as “designer solvents”. Ionic liquids are finding uses as solvents and reaction media in a large number of diverse applications such as carbon dioxide sen- sors, [2] catalysis, [3, 4] energy storage, [5] nanostructure synthesis, [6, 7]
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Graphene-Based Supercapacitors Using Eutectic Ionic Liquid Mixture Electrolyte

Graphene-Based Supercapacitors Using Eutectic Ionic Liquid Mixture Electrolyte

room temperature and below. A maximum gravimetric capacitance of 175 F.g "1 (85 mAh.g "1 ) was obtained at 80 ! C. 130 F.g "1 (63 mAh.g "1 ) and 100 F.g "1 (49 mAh.g "1 ) were still delivered at -20 ! C and -30 ! C respectively. Besides, a volumetric capacitance of 50 F.cm "3 was achieved with a thick graphene film (60 m m). The outstanding performance of such compact graphene film in the eutectic ionic liquid mixture electrolyte makes it a promising alternative to activated carbon for supercapacitor applications, especially under extreme temperature conditions.
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Cationic Dye Removal from Aqueous Solutions Using Ionic Liquid and Nonionic Surfactant-Ionic Liquid Systems: A Comparative Study Based upon Experimental Design

Cationic Dye Removal from Aqueous Solutions Using Ionic Liquid and Nonionic Surfactant-Ionic Liquid Systems: A Comparative Study Based upon Experimental Design

of attention from researchers (Iglesia and Montenegro, 1996). The existence of effective ion association between IL and dye with opposite charge allows an IL with a large cationic site to form ion pairs with negatively charged sulfonate groups of dyes (Buwalda et al., 1999). These complexes aggregate and precipitate readily in the solution at room temperature. But when the latter increases, the aggregates dis- sociate and the dye returns to solution (Safavi et al., 2008). However, methylene blue is a cationic dye (Figure 3). So, it seems reasonable that the IL anionic site (hexa- fluorophosphate) associates with the 3,7-bis(dimethylamino)-phenothiazin-5-ium cation to form the [C4mim]PF6-methylene blue 1:1 complex (Pei et al., 2012). In addition, it was also found that [C4mim]PF6 forms quite strong associates with
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TTA solvation kinetics in the ionic liquid Bumim$Tf_2N$

TTA solvation kinetics in the ionic liquid Bumim$Tf_2N$

TTA, purchased from ACROS Organics (99.5%), was contacted with deionized water in slight excess for about one week in the dark and at room temperature. The solid obtained, after drying, was recrystallized from diethylether, and the white powder, characteristic of the hydrated keto form of TTA [11], was stored at 8 °C in the dark. The presence of TTA, under the predominant keto-hydrate form, was confirmed by spectrophotometric measurements (strong adsorption between 275-300 nm) [11-13]. A kinetic study has shown that the product is stable over several months when stored in the above conditions.
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High temperature carbon–carbon supercapacitor using ionic liquid as electrolyte

High temperature carbon–carbon supercapacitor using ionic liquid as electrolyte

∗ Corresponding author. Tel.: +33 5 61 55 68 02; fax: +33 5 61 55 61 63. E-mail address: simon@chimie.ups-tlse.fr (P. Simon). type of supercapacitors has appeared: the hybrid systems, where faradaic and carbon electrodes are associated in order to increase the specific energy [13–15] . Activated carbon-based superca- pacitors are the most developed technology because of their low cost, large capacitance and long cycling stability. In these devices the charge storage is electrostatic and the electrolyte ions are reversibly adsorbed in the electrochemical double-layer of the porous carbon electrode structure [16] . The most recent activated carbon supercapacitors on the market use electrolyte solutions based on aprotic solvents, typically acetonitrile (ACN) or carbonate-based solvents (propylene carbonate, ethylene car- bonate, etc.) and operate at room temperature (RT) with cell voltage of 2.3–2.5 V. However, for the operating conditions required in HEV applications, these commercial devices are not the best that could be designed to operate at these temperatures because (i) the electrochemical stability window of organic sol- vents decreases with increasing temperatures [17,18] and (ii) the increase of the maximum cell voltage significantly reduces the cycle-life. Moreover, the high vapour pressure of ACN-based electrolytes requires a careful and too expensive thermal control.
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From tectons to luminescent supramolecular ionic liquid crystals

From tectons to luminescent supramolecular ionic liquid crystals

First published on the web Xth XXXXXXXXX 200X DOI: 10.1039/b000000x 5 New phosphorescent and room-temperature liquid-crystalline materials were obtained by combining dicyanometallate anions with dicationic bisamidinium based tectons bearing four peripheral lipophilic pyrogallate moieties.

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Ionic Schiff base dioxidomolybdenum(VI) complexes as catalysts in ionic liquid media for cyclooctene epoxidation

Ionic Schiff base dioxidomolybdenum(VI) complexes as catalysts in ionic liquid media for cyclooctene epoxidation

1. Introduction The use of two-phase solvent systems, especially those based on water-soluble ligands and their metal complexes [1], has emerged in the last decade as a synthetic strategy for homogeneous catalysis. In this respect, room temperature Ionic Liquids (ILs) as solvents have proved to be mainly useful for these types of two-phase catalytic reactions [2]. Particularly, the interest in ILs as alternatives to organic solvents has been growing with regards to economic and ecological concerns [3]. However, ILs have only recently been applied to metal transition catalysis [4] with the benefit of a convenient catalyst separation, hence, recovery/recycling procedure. Catalyzed oxidations in ILs have resulted in a few processes that are more efficient than those carried out in organic solvents [5]. The efficiency of the catalyst/ILs system is strongly dependent on the nature of the ILs. The rationalization of its role in association with the catalyst remains an unexplored research area. Nevertheless, Dupont et al have already shown the “non-innocent” nature of ILs under certain reaction conditions [6].
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