Piperidinium-based Ionic Liquids Research Articles

Anticorrosive performance of piperidinium-based ionic liquid on 6061 aluminium alloy in HCl medium

Anticorrosive performance of piperidinium-based ionic liquid on 6061 aluminium alloy in HCl medium

Easy to scale up synthesis of a high-purity piperidinium based ionic liquid combining both sustainability and cost-effectiveness

Ionic liquids have attracted much attention these last years because they have been identified as a new class of media offering interesting opportunities to transfer the traditional chemical processes to new, clean and eco-friendly technologies. But in order for these compounds to achieve their commercial potential, it must be demonstrated that they can be produced in hundreds of kilograms at a time in a benign simple and highly efficient way. However, the main applications in which they are involved require a high dregree of purity. In the context of the circular economy and with the aim of developing a generic, straightforward, economical and eco-friendly method for high-purity piperidinium-based ionic liquids preparation, we investigate here the experimental conditions of determining step of the synthesis i.e. the Menshutkin reaction. This enables use to offer a high-yield and high-quality protocol, that is easy to scale up and that combines sustainability with cost-effectiveness.

Synthesis and performance of piperidinium-based ionic liquids as catalyst for biomass conversion into 3-acetamido-5-acetylfuran

Ionic liquids have shown good catalytic performance and been widely used in the biomass conversion process due to their unique properties, including environmentalfriendship, low toxicity, and simple preparation. In this work, a series of novel piperidinium-based ionic liquids were synthesized under mild conditions via a simple protonation reaction or nucleophilic substitution reaction. Among them, 4,4′-(propane-1,3-diyl)bis(1-(carboxymethyl)piperidin-1-ium) chloride ([PDCMPi]Cl) displayed the best catalytic performance. The highest yield (42.81 %) of 3A5AF from NAG was obtained after reacting in N-methyl-pyrrolidone (NMP) in the presence of piperidinium-based ionic liquids at 180 °C for 20 min under normal atmospheric conditions. Additionally, ionic liquid [PDCMPi]Cl showed good catalytic activity in six repeated catalytic runs. Meanwhile, a possible reaction pathway was also proposed on the basis of the results of NMR spectra.

Long-Range Organization Study of Piperidinium-Based Ionic Liquids by Polarizable Molecular Dynamics Simulations.

The nanoscale organization of some classes of ionic liquids is responsible for their singular properties. In this paper, we use polarizable molecular dynamics simulations and small-angle X-ray scattering to probe the structure of two piperidinium- and (trifluoromethylsulfonyl)imide-based ionic liquids ([EBPip+][NTf2-] and [EOPip+][NTf2-]) that differ in the alkyl chain length of their cation. The X-ray scattering intensities calculated numerically, from the radial distribution functions, are in excellent agreement with the experimental data. The analysis of the different contributions of the X-ray scattering data allowed us to highlight the correlations responsible for the low q peak observed for the long-chain alkyl cations. New angular analyses showed that anions were more likely to align with alkyl chains as their size increased, inducing angular correlation between anions at larger distances. They also showed that the long alkyl chains of the cations aligned more with each other than the short ones. These more aligned alkyl chains induce a smaller volume of the apolar microdomains compared to the well-studied imidazolium-based ionic liquids, leading to the smaller correlation distance for piperidinium-based ionic liquids.

Weak Intermolecular Interactions and Molecular Cluster in Ionic Liquids

Presently, we are working on weak intermolecular interaction (aliphatic H-bonding and ?-? stacking interaction) in imidazolium and piperidinium-based ionic liquids. The weak interactions play a crucial role in the physical properties of ILs. Further, the significance of weak interactions on cluster formation and extended intermolecular interaction in these ILs have been investigated in our laboratory. The vibrational spectroscopic techniques (Raman and FTIR) have been employed to understand the effect of H-bonding interaction on physical property and molecular cluster formation of ILs. Further, DFT calculations help for better understanding the intermolecular interactions at the molecular level.

Electrochemical, thermodynamic, and physical properties of tetradecyltrihexylphosphonium ([P6,6, 6,14]+) and methyl-propyl piperidinium containing ionic liquids and their propylene carbonate solutions

The viscosity, conductivity, electrochemical window and related thermodynamic properties such as excess volume and dynamic viscosity deviation of two phosphonium ionic liquids were measured and calculated for “as-supplied” and dried neat liquids and also v/v mixtures of 99/1, 95/5, 90/10, 75/25, and 50/50 of the ionic liquids with propylene carbonate (PC). Tetradecyltrihexylphosphonium dicyanamide ([P6,6,6,14]+dicyanamide), Cyphos 105, and tetradecyltrihexylphosphonium bis(trifluororomethanesulfonyl)imide (called bistriflimide) ([P6,6,6,14]+bistriflimide), Cyphos 109, ionic liquids were studied. Generally speaking, there were slight differences in the measured properties of the wet and dried IL solutions which were reflected in differences if the calculated properties. The measured and calculated properties were compared with those collected and derived from a piperidinium-based ionic liquid, methyl-propyl piperidinium bistriflimide. Arrhenius plots for both the viscosity and conductivity were linear, with the linearity of the Litovitz plots being slightly higher. The viscosity and conductivity of the phosphonium solutions yielded Walden Plots that differed from Walden plots of piperidinium solutions and other ionic liquid solutions. For the phosphonium based ionic liquids, the ionicity was found to increase with increasing dilution in propylene carbonate. The electrochemical windows of the ionic liquids were determined as a function of the concentration of the ionic liquid present in the solution. The size of the window generally initially decreased and then increased with the addition of PC for the [P6,6,6,14]+dicyanamide ionic liquid increasing from 3.4 V in the 95/5 v/v (volume Cyphos 105) to volume of PC solvent) to 3.7 in the 50/50 dried IL case. The electrochemical windows of the dried liquids were slightly larger 3.5 V for the 95/5 v/v and 4.2 V for the 50/50 v/v Cyphos 105/PC solutions. The electrochemical window was larger and the conductivity was higher for the piperidinium IL solutions, but since the ionicity increases with dilution, the phosphonium based IL solutions may prove favorable for processes such as electrochemical reduction.

Are Ionic Liquids Safe for 18650 Ni-Rich Li-Ion Battery Cells?

Although ionic liquids have been widely investigated as the electrolyte composition and believed that they can enhance the safety of lithium-ion batteries (LIBs), we have unexpectedly found in this work that they are not safe for Ni-rich LIBs. Hybrid electrolytes of piperidinium-based ionic liquids with different alky chains and carbonate-based solvents can provide poor cell capacity and lead to severe safety concerns of 18650 Ni-rich NCA Li-ion battery cells. The LIB cells using the hybrid electrolytes including 50% C3-PIPTFSI and 50% C4-PIPTFSI show 2628.5, 2481.0, and 2245.5 mAh/cell providing the coulombic efficiencies of 94.5%, 94.8%, and 78.3%, respectively. Whilst the cells using the conventional electrolyte (1 M LiPF6 in EC:DMC:EMC at 1:1:1 v/v) provide higher initial discharge capacity 2888.8 mAh/cell with a greater coulombic efficiency of 99.0% at the 1st cycle. Moreover, the explosion of the cells using the hybrid electrolytes by the impact test (UN38.3) is severely observed due to high carbon content of ionic liquids behaving as a fuel and their mismatch electronic properties or their incompatibility with graphite anode. In additionally, the result from classical MD simulation suggests that Cx-PIPTFSI species are involved in the first coordination shell instead of EC molecule in solvation Li-ion structure in hybrid electrolytes system. The EC molecules become a free- solvent, resulting in worse oxidative stability. This finding may further guide the further development of high-safety Ni-rich LIBs.

Ultrasonic-Assisted Technique as a Novel Method for Removal of Naphthenic Acid from Model Oil Using Piperidinium-Based Ionic Liquids.

In this study, piperidinium-based ionic liquids (IL) containing trifluoromethanesulfonate, phenolate, and dicyanamide anions were synthesized. Using the ILs, extraction of naphthenic acid from highly acidic oil with a total acid number (TAN) of 1.44 was studied. Two agitation techniques have been implemented for the extraction process, which were mechanical stirring and ultrasonic-assisted irradiation. 1-Butyl-1-methylpiperidinium phenolate [BMPi][Phe] showed the best potential in extracting naphthenic acid from oil, with complete removal of naphthenic acid with IL-to-oil ratios of 0.010 and 0.0025 for the mechanical stirring method and the ultrasonic-assisted method, respectively. Ultrasonic-assisted extraction process shows very good potential in enhancing the extraction efficiency of naphthenic acid. Optimization and study on the effects of ultrasonic parameters, namely, IL-to-oil ratio, ultrasonic amplitude, and time, were studied through response surface methodology (RSM). Using [BMPi][Phe], the optimum conditions obtained are IL-to-oil ratio of 0.03, 53.91% of amplitude, and 4.29 min of extraction time. Under these optimum conditions, 100% removal of naphthenic acid was achieved.

Novel piperidinium-based ionic liquid as electrolyte additive for high voltage lithium-ion batteries.

Conventional carbonate-based electrolyte is prone to oxidative decomposition at high voltage (over 4.5 V vs. Li/Li+), which leads to the bad oxidation stability and inferior cycling performance of lithium ion batteries (LIBs). To solve these problems, a novel ionic liquid (IL) N-butyronitrile-N-methylpiperidinium bis(fluorosulfonyl)imide (PP1,CNFSI) was synthesized and explored as the additive to the LiPF6–ethylene carbonate (EC)/dimethyl carbonate (DMC) electrolyte. For the cell performance, the addition of PP1,CNFSI not only inhibits overcharge phenomenon, but also improves discharge capacity, thus enhancing capacity retention capability. Compared to the cell with blank electrolyte, the capacity retentions of adding 15 wt% PP1,CNFSI into the electrolyte were improved to 96.8% and 97% from 82.8% and 78.7% at 0.2 C and 5 C, respectively. The effects of PP1,CNFSI on the LNMO cathode surface were further investigated by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). It reveals that PP1,CNFSI addition drives the formation of solid electrolyte interphase (SEI) film which suppresses oxidative decomposition of the electrolyte and protects the structure cathode material.

Piperidinium-Based Ionic Liquids as an Electrolyte Solvent for Li-Ion Batteries: Effect of Number and Position of Oxygen Atom in Cation Side Chain on Electrolyte Property

In the pursuit of developing reliable Li-ion batteries with high performance and safety, the use of ionic liquids is one of the most promising approaches due to its high thermal stability. There is, however, the critical issue concerning the significantly low Li-ion diffusion in an electrolyte solution, which is directly linked to the degradation of their rapid charge−discharge properties. Ionic liquids with ether-substituted cation have generated much interest as electrolyte solvents for Li-ion batteries because the ether group functions to reduce the coordination number and increase ionic conductivity. In the present study, we synthesized six types of ionic liquids consisting of bis(trifluoromethanesulfonyl)amide (TFSA) anions and piperidinium-based cations in which the attached side chains are 1-((2-methoxyethoxy)methyl)-1-methylpiperidinium (PP1MEM), 1-butoxymethyl-1-methylpiperidinium (PP1BM), 1-methyl-(2-propoxyethyl)piperidinium (PP1PE), 1-(3-ethoxypropyl)-1-methylpiperidinium (PP1EP), 1-(4-methoxybutyl)-1-methylpiperidinium (PP1MB), and 1-hexyl-1-methylpiperidinium (PP16). It was found that the ionic liquid with PP1MEM cations with two oxygen atoms in the side chain exhibited the lowest solvation number of TFSA anions (1.56), whereas PP1BM (1.78), PP1PE (1.86), PP1EP (2.08), and PP1MB-TFSA (2.07) resulted in a larger number, as the oxygen atoms in the alkyl side chain are located far from the positively charged nitrogen atoms. PP1MEM-TFSA with small solvation numbers enhanced the ionic conductivity and thereby achieved high electrode performance.

Ionic Liquid-Based Electrolytes for High-Voltage Li-Ion Batteries

The lithium-ion battery (LIB) with high energy density is highly demanded for electric vehicle application. To increase the energy density of LIB, one popular approach is to elevate the operation potential of the cathode or the voltage of the cell. However, at high potentials or high voltages, the state-of-the-art (SOA) organic carbonate-based electrolytes tend to be oxidatively decomposed at the cathode surface causing gassing issue, low Coulombic efficiency, transition metal ion dissolution and rapid capacity fade of the full cell. In this presentation, we studied the piperidinium-based ionic liquids as an electrolyte candidate for high-voltage lithium-ion battery due to their low melting point, low vapor wide electrochemical window, nonflammability and low/non-volatile merits. When doped with various amount of lithium fluorosulfonylimide salt (LiFSI), the piperidinium-FSI- based ionic liquid showed much improved cycling performance in the NMC532/Li cells at voltages higher than 4.5 V compared with the SOA electrolyte - 1.2 M LiPF6 EC/EMC (3/7 wt.). The feasibility as a practical electrolyte for the next generation LIB was evaluated by its physical properties and electrochemical stability on both cathode and anode. Furthermore, Raman spectroscopy and molecular dynamic simulations (MD) were conducted shedding light on the sophisticated 3D-network structure containing piperidinium cation, FSI- and Li+ species at various LiFSI concentrations.

Conductivity of N-(2-methoxyethyl)-substituted morpholinium- and piperidinium-based ionic liquids and their acetonitrile solutions

N-ethyl-N-(2-methoxyethyl)-morpholinium bis(trifluoromethylsulfonyl)imide [Et(MEO)Mor][TFSI], N,N-bis(2-methoxyethyl)-morpholinium bis(trifluoromethylsulfonyl)imide [Bis(MEO)Mor][TFSI] and N,N-bis(2-methoxyethyl)-piperidinium bis(trifluoromethylsulfonyl)imide [Bis(MEO)Pip][TFSI] room-temperature ionic liquids (RTILs) were synthesized and their electrochemical properties were studied. Three stages of synthesis of RTILs were used, including the alkylation of secondary and tertiary amines and the anion exchange. The structure of RTILs was confirmed by1H, [Formula: see text]C, H,H-COSY,1H–[Formula: see text]C correlation spectroscopy NMR and XPS. Three main approaches based on the Arrhenius, Litovitz, and Vogel–Fulcher–Tammann equations were used to analyze the ion transport properties of RTILs. In addition, the electrical conductivity of the binary acetonitrile solutions of RTILs was studied. It was found that the activation energy and conductivity of RTILs depended on their polarity and ability to associate which affects the mobility of charge carriers and viscosity of the system.

A novel method for predicting melting point of ionic liquids

For industrial applications, it is important to know phase transition properties such as melting points of ionic liquids (ILs). A novel correlation is introduced to predict melting points of important classes of ILs including imidazolium-, pyridinium-, pyrrolidinium-, ammonium-, phosphonium-, and piperidinium-based ILs and different type of anions with specific cation/anion moieties. It is based only on the number of some of atoms in cationic and anionic structures as well as two correcting functions for the presence of some specific cation/anion moieties. The numbers of carbon, hydrogen and nitrogen atoms are used for cation. Meanwhile, the numbers of hydrogen, nitrogen, bromine, chlorine and aluminum atoms are applied for anion. The measured data of 195 different types of ILs were used to derive the new correlations. The calculated coefficient of determination (R2), root mean square error (RMS), mean absolute error (MAE), mean absolute percent errors (MAPEs) and maximum of errors of the new model are 0.857, 26.1 K, 20.1 K, 6.5 and 91.2 K, respectively. Meanwhile, the calculated RMS, MAE, MAPE and maximum of errors for one of the best available group contribution (GC) methods where it can be applied only for 159 ILs are 53.6 K, 35.9 K, 11.6 and 253.6 K, respectively. For further 48 ILs with complex structure of cations and different anions, the values of RMS, MAE, MAPE and maximum of errors for the new model is also much lower than GC method. These results confirm that the reliability of the new model is good as well as it can be applied for a wide range of imidazolium-, pyridinium-, pyrrolidinium-, ammonium-, phosphonium-, and piperidinium-based ILs with different type of anions.

(Invited) Conductivity and Dielectric Relaxations in New Morpholinium- and Piperidinium-Based Ionic Liquids

Room Temperature Ionic Liquids (RTILs) are key materials for the development of new energy storage and conversion systems [1]. In the past decade several relevant properties such as their negligible vapour pressure, non-flammability, and high room-temperature conductivity were explored in order to obtain safer and better performing devices [2]. Despite of this, the complex interplay existing between the IL nanostructure and the conductivity mechanism is still under discussion within the scientific community [3]. Following this, the synthesis of new ILs and the investigation of their electrical properties are of crucial importance and could pave the way to new applications in the field of ion-conducting materials [4, 5]. This contribution summarizes the electrical study of a family of ILs based on 1-methylmorpholinium (MM+) and 1-methylpiperidinium (MP+) cations. The MM+ and MP+ cations have been synthesized comprising two different alkyl side chain substituents on the nitrogen atom, namely 1-methoxyethyl (ME) and 1-ethoxyethyl (EE) groups. A set of four cations (ME-MM+, EE-MM+, ME-MP+ and EE-MP+) neutralized by TFSI-anions is obtained, thus giving rise to four new RTILs. The structure of these ILs allows the systematic investigation of the presence of oxygen atoms on the aliphatic ring (see morpholinium vs. piperidinium cations) with respect to the different substituent side chain length (see methoxyethyl vs.ethoxyethyl groups). The effect of the oxygen atom position on the diffusion of conformational states as well as the charge transfer mechanism is particularly interesting for future Lithium battery applications in which the oxygen atoms are expected to play a crucial role on the migration of Li cations. At this regard, Broadband Electrical Spectroscopy (BES) measurements were undertaken to elucidate the electrical response of the ILs in terms of dielectric relaxations and polarization phenomena. At T<Tg (Tg=glass transition temperature) dielectric relaxations are present, associated with the rotational motions of morpholinium and piperidinium cations bearing permanent dipole moment; at T>Tg, interdomain polarization events are detected. These polarization events are associated with the presence of cation and anion nanocluster aggregates with different permittivities. The results allow us to correlate the dielectric relaxations of the different cations with the overall long-range charge migration, thus elucidating the interplay existing between conductivity and nanostructure of this new ILs.

New Ether-functionalized Morpholinium- and Piperidinium-based Ionic Liquids as Electrolyte Components in Lithium and Lithium-Ion Batteries.

Here, two ionic liquids, N-ethoxyethyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide (M1,2O2 TFSI) and N-ethoxyethyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide (P1,2O2 TFSI) were synthesized and compared. Fundamental relevant properties, such as thermal and electrochemical stability, density, and ionic conductivity were analyzed to evaluate the effects caused by the presence of the ether bond in the side chain and/or in the organic cation ring. Upon lithium salt addition, two electrolytes suitable for lithium batteries applications were found. Higher conducting properties of the piperidinium-based electrolyte resulted in enhanced cycling performances when tested with LiFePO4 (LFP) cathode in lithium cells. When mixing the P1,2O2 TFSI/LiTFSI electrolyte with a tailored alkyl carbonate mixture, the cycling performance of both Li and Li-ion cells greatly improved, with prolonged cyclability delivering very stable capacity values, as high as the theoretical one in the case of Li/LFP cell configurations.

INVESTIGATING THE LONG-TERM STABILITY AND KINETICS OF SUPEROXIDE ION IN DIMETHYL SULFOXIDE CONTAINING IONIC LIQUIDS AND THE APPLICATION OF THIOPHENE DESTRUCTION

Abstract The long-term stability of superoxide ion (O2•−) with four ionic liquids (ILs), namely 1-(2-methoxyethyl)-1-methylpiperidinium tris(pentafluoroethyl)trifluorophosphate [MOEMPip][TPTP], 1-(3-methoxypropyl)-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide [MOPMPip][TFSI], N-ethyl-N,N-dimethyl-2-methoxyethylammonium bis(trifluoromethylsulfonyl)imide [N112,1O2][TFSI], and ethyl-dimethyl-propylammonium bis(trifluoromethylsulfonyl)imide [EDMPAmm][TFSI], was studied for up to 24 h using two-second intervals. This was achieved by chemical generation of O2•− by dissolution of potassium superoxide salt in dimethyl sulfoxide and the subsequent addition of the IL. The decrease in the concentration of O2•− after the introduction of the IL was monitored using a UV-vis spectrophotometer. The ammonium-based ILs were found to be more stable than piperidinium-based ILs. To the best of our knowledge, this was the first time that O2•− stability with ILs has been monitored continuously for up to 24 h. This should provide a better insight into the stability and kinetics of O2•− for industrial applications and its role in energy-storage devices. The most appropriate IL as a medium was [EDMPAmm][TFSI], and O2•− generated in this IL was used to destroy nearly 90% of thiophene.

Piperidinium-based ionic liquid electrolyte with linear solvent and LiODFB for LiFePO4/Li cells at room and high temperature

Lithium difluoro(oxalato)borate (LiODFB) combines the advantages of the salts LiBOB and LiBF4 when used in electrolytes for lithium ion cells.

Electrodeposition of high aspect ratio single crystalline tellurium nanowires from piperidinium-based ionic liquid

Template-free electrodeposition of high aspect ratio Te nanowires is presented. Nanowires were obtained from the ionic liquid 1-ethyl-1-octyl-piperidinium bis(trifluoromethylsulfonyl)imide (EOPipTFSI) containing 1-ethyl-1-octyl-piperidinium bromide (EOPipBr). The influence of the EOPipBr content on the dimensions and the morphology of the nanostructures was studied. Several micrometers long tellurium nanowires with diameters between 100 and 180nm were obtained when the EOPipBr content of the electrolyte is higher than 0.5mol%. By decreasing the bromide concentration, the electrochemical behavior of TeIV solutions becomes more complex, leading to several reduction signals. By varying the applied overpotential, hair-like single crystalline nanowires can then be obtained with a diameter which can reach 50nm and a length of 70μm leading to a high aspect ratio of almost 2000. High Resolution Transmission Electron Microscopy analyses show that the nanostructures are single crystalline and reveal a growth along the c-axis, with a smooth interface. No surface contaminants were observed by Scanning Transmission Electron Microscopy, proving that halide ions do not play the role of capping agents.

A Piperidinium-Based Ester-Functionalized Task-Specific Ionic Liquid As Electrolytes in Li/LiFePO4 Batteries

Lithium batteries are the most attractive candidate to replace the traditional energy resources due to their high working voltage, high specific energy and long cycle life [1,2]. However, the widely use have been limited by their safety issues, especially under the condition of abusing or overcharging. In order to solve this issue, it is significant to screen a safe material as lithium batteries electrolyte.Room temperature ionic liquids (RTILs) have aroused much attention for use in lithium batteries, owing to their low volatility, inflammability, wide electrochemical window and high ionic conductivity [3]. Particularly, their excellent thermal stability makes them key to solve the safety issues of lithium batteries at high temperatures and their physicochemical properties can be tuned by introducing functionalized groups onto the cation or anion of RTILs. The functionalized task-special ionic liquids can reduce the viscosity and enhance their ionic conductivity of RTILs. In this study, a piperidinium-based ionic liquid, N-methyl-N-methoxycarbonylpiperidinium bis(trifluoromethanesulfonyl)imide ([MMOCPip][TFSI]), was synthesized by anion exchange reaction and used as an additive to electrolyte of Li-ion battery. The electrochemical performance of the electrolytes had been evaluated by electrochemical tests, such as the line sweep voltammetry, cyclic voltammetry and impedance spectroscopy.The N-methyl-N-methoxycarbonylpiperidinium bis(trifluoromethanesulfonyl)imide ([MMOCPip][TFSI]) ionic liquid was prepared by mixing equimolar N-methyl-N-methoxycarbonylpiperidinium bromide ([MMOCPip][Br]) and bis(trifluoromethanesulfonyl)imide lithium at room temperature in deionized water and by stirring for several hours until a hydrophobic [MMOCPip][TFSI] layer was formed below the water phase [4]. The ionic conductivity of [MMOCPip][TFSI] was 0.77 mS·cm-1 (25℃) and 2.41 mS·cm-1 (60℃), however, after adding 0.1 M LiTFSI, the ionic conductivity decreased to 0.51 mS·cm-1 (25℃) and 1.85 mS·cm-1 (60℃), respectively. The electrochemical window was 0.5 V~5.8 V (vs. Li+/Li), which was enough widely that could be used as common electrode material. The Li-ion transference number of ionic Liquid electrolyte containing 0.1 M LiTFSI was 0.56. The battery tests indicated that the [MMOCPip][TFSI] obviously improved the cyclability of the LiFePO4 cell. For the Li/ LiFePO4 half-cells, after 20 cycles at room temperature at 0.1 C, the discharge capacity was 109.7 mAh·g-1 with 98.7% capacity retention in the [MMOCPip][TFSI]/0.1 M LiTFSI electrolyte. The good electrochemical performance demonstrated that the [MMOCPip][TFSI] could be used as electrolyte additive for lithium batteries. Keywords: Ionic liquid; Li-ion battery; Ionic conductivity; Transference number Reference: [1] Wongittharoma N, Wang CH, Wang YC, Fey GTK, Li HY, Wu TY, Lee TC, Chang JK (2014). Charge-storage performance of Li/LiFePO4 cells with additive incorporated ionic liquid electrolytes at various temperatures. J Power Sources. 260: 268–275.[2] Yang J, Zhou XY, Zou YL, Tang JJ (2011). A hierarchical porous carbon material for high power, lithium ion batteries. Electrochim Acta. 56: 8576–8581.[3] Pandian S, Raju SG., Hariharan KS, Kolake SM, Park DH, Lee MJ (2015). Functionalized ionic liquids as electrolytes for lithium-ion batteries. J Power Sources. 286: 204-209. [4] Yang PX, Cui WY, Li LB, Liu L, An MZ (2012). Characterization and properties of ternary P(VdF-HFP)-LiTFSI-EMITFSI ionic liquid polymer electrolytes. Solid State Sciences. 14(5), 598–606. Figure 1

Interactions of pyridinium, pyrrolidinium or piperidinium based ionic liquids with water: Measurements and COSMO-RS modelling

Looking for a better knowledge concerning water and ionic liquids (ILs) interactions, a systematic study of the activity coefficients of water in pyridinium, pyrrolidinium and piperidinium-based ILs at 298.2 K is here presented based on water activity measurements. Additionally, the study of the structural effects of the pyridinium-based cation is also pursued. The results show that non-aromatic ILs are interacting more with water than aromatic ones, and among the ortho, meta and para isomers of 1-butyl-methylpyridinium chloride, the ortho position confers a more hydrophilic character to that specific IL. The physical-chemistry of the solutions was interpreted based on dissociation constants, natural bond orbitals and excess enthalpies providing a sound basis for the interpretation of the experimental observations. These results show that hydrogen bonding controls the behavior of these systems, being the anion-water one of the most relevant interactions, but modulated by the anion–cation interactions.