Low Viscosity Solvents Research Articles

Energy-efficient CO2 capture using novel low-viscosity water-lean aromatic amine solvent MBA/BDMA/EG/H2O: Performance, mechanism and thermodynamics

To address the challenges of high regeneration energy and corrosion in traditional mixed amine absorbents, as well as the increased viscosity issues in water-lean absorbents post-saturation, this study introduces the co-solvent ethylene glycol (EG) to replace part of the water in the high stability N-methylbenzylamine (MBA) and N, N-dimethylbenzylamine (BDMA) systems, resulting in a novel water-lean aromatic amine solvent, MBA/BDMA/EG/H2O, is proposed as an alternative solution. The addition of the tertiary amine BDMA significantly enhanced the regeneration efficiency of the absorbent. When the mass ratio of MBA/BDMA/EG/H2O is set at 1.5:1.5:3.5:3.5, the CO2 loading reaches 0.36 mol/mol, while the viscosity is only 10.82 mPa⋅s at room temperature. The CO2 capture mechanism of this absorbent was elucidated using 13C NMR and quantum chemical calculations. Initially, CO2 reacts with MBA to form MBACOO-/MBAH+. Subsequently, MBA+COO– undergoes deprotonation to produce MBAH+ and BDMAH+. As the concentration of free MBA decreases to a certain level, BDMA undergoes hydrolysis, resulting in the formation of HCO3–. In the later stages of absorption, some of the carbamate products convert to unstable alkyl carbonates by reaction with EG. Notably, the regeneration energy of MBEH is reduced by 21.1 % (estimate), compared to 30 wt% MEA aqueous solution. The corrosion rate of 30 wt% MEA (after absorption) on carbon steel is 3.6 times higher than that of MBEH (after absorption). Therefore, the proposed MBEH solution presents a promising absorbent with excellent desorption performance, low viscosity, reduced regeneration energy, and low corrosion rate.

Enhanced efficiency and selectivity of carbon monoxide absorption by cuprous-based bimetallic deep eutectic solvents via iron activation

The absorption/utilization of carbon monoxide (CO) is critical due to its wide application in chemical production processes (e.g., acylation), and its toxicity/environmental impact. However, traditional copper-ammonia solutions in industry have limitations such as the deactivation of copper ions and high viscosity, which hinder efficient CO absorption under atmospheric conditions. In this work, a series of low-viscosity bimetallic deep eutectic solvents (DESs) with high CO absorption capacity were developed by mixing metal chlorides with [Emim]Cl and CuCl in specific molar ratios. Comprehensive studies of their physical properties (density and viscosity) and CO absorption performance revealed that [Emim]Cl-CuCl-1.0FeCl3 exhibited the lowest viscosity (57.4 cP) and a nearly equimolar CO absorption capacity (0.9 mol/mol). Moreover, the selectivity for CO/N2 (730), CO/CO2 (22), and CO/H2 (52) at 298.2 K and 100 kPa was also satisfied. The data of Raman and FT-IR spectra demonstrated that FeCl3 effectively activated cuprous sites in CuCl and significantly enhanced the CO absorption performance of cuprous-based bimetallic DESs. Furthermore, [Emim]Cl-CuCl-1.0FeCl3 showed excellent reusability after six absorption–desorption cycles. Therefore, we believe that this work provides a route for the effective activation of cuprous sites in cuprous-based bimetallic DESs to achieve efficient and reversible CO absorption at atmospheric conditions.

Diffusion and thermodynamic properties of lithium polysulfides in different solvents: a molecular dynamics approach.

Li-S batteries are promising alternatives due to their proven increased gravimetric capacity compared to Li-ion batteries. However, their development is hindered by many technical issues, one of the most challenging being the dissolution and shuttle of polysulfide species, which causes irreversible loss of cathode material leading to rapid capacity fading. Among the possible strategies to mitigate this effect, the choice of suitable solvents is easy to implement and has large room for improvement. To guide this quest, computationally-aided optimization is a powerful tool, provided that suitable descriptors are used to screen possible solvents. In this work, molecular dynamics simulations were performed for a typical lithium polysulfide Li2S6 dissolved in different solvents. Diffusion coefficients and their related activation energies were calculated, and thermodynamic properties like solvation energies and entropies were also evaluated. Additionally, a theoretical framework for computing the relative solubilities of lithium polysulfide is provided. For the set of solvents considered, we found that the system's viscosity appears as an important descriptor to correlate with different system properties. The donor number of the solvent also appears as a valid descriptor, for low-viscosity solvents. In general, it was found that higher viscosity solvents lead to lower diffusion rates and higher polysulfide solubility. These results suggest that the optimal choice to reduce the shuttle is a trade-off between high-viscosity solvents to reduce polysulfide diffusion and low-viscosity solvents to reduce its solubility, which could be further improved by properly tuning the donor number.

Thioflavin-T: A Quantum Yield-Based Molecular Viscometer for Glycerol-Monohydroxy Alcohol Mixtures.

Molecular rotor dye thioflavin T (ThT) is almost nonfluorescent in low-viscosity solvents but highly fluorescent when bound to amyloid fibrils. This unique property arises from the rotation of the dimethylaniline moiety relative to the benzothiazole moiety in the excited state, which drives the dye from an emissive locally excited state to a twisted intramolecular charge-transfer state. This process is viscosity-controlled, and therefore, we can use the quantum yield of ThT to assess the viscosity of the environment. In this study, we have investigated the quantum yield of ThT (φThT) in various compositions of six alcoholic solvent mixtures of glycerol with methanol, ethanol, n-propanol, iso-propanol, n-butanol, and tert-butanol. We have proposed an empirical model using φThT as a function of the mole fraction of glycerol to estimate the interaction parameters between the components of the solvent mixtures. This analysis allowed us to predict the extent of nonideality of the solvent mixtures. The Förster-Hoffmann- and Loutfy-Arnold-type power law relationship was established between the quantum yield of ThT and bulk viscosity for solvent mixtures of methanol, ethanol, n-butanol, and tert-butanol with glycerol, and it was found to be similar in nature in all the four mixtures. Applying this knowledge, we proposed a methodology to quantify and predict the bulk viscosity coefficient values of several compositions of n-propanol-glycerol and iso-propanol-glycerol mixtures which have not been previously documented.

Low-viscosity acidic deep eutectic solvent for extraction of valuable metals from spent NCM

In this study, a low-viscosity and reducing acidic deep eutectic solvent is synthesized from ethylene glycol and malonic acid for leaching valuable metals from spent lithium-ion battery cathode materials. The influence of various experimental parameters on the efficiency of metal leaching is systematically investigated. Under optimal conditions, the leaching efficiency of Li, Ni, Co, and Mn is ca. 100%. In addition, the mechanism and leaching kinetics of the system are investigated. The transition metal ions are reduced to a lower valence state in the presence of the tested deep eutectic solvent; resulting in efficient leaching, which is controlled by the chemical reaction. Separating Li+ from transition metal ions is then achieved by recovering the transition metal ions from the leaching solution by co-precipitation. The co-precipitated products are used as precursors for preparing cathode materials and producing NCM523 coin cells with good electrochemical performance.

3D manipulation and dynamics of soft materials in 3D flows

Flow-based manipulation of particles is an essential tool for studying soft materials, but prior work has nearly exclusively relied on using two-dimensional (2D) flows generated in planar microfluidic geometries. In this work, we demonstrate 3D trapping and manipulation of freely suspended particles, droplets, and giant unilamellar vesicles in 3D flow fields using automated flow control. Three-dimensional flow fields including uniaxial extension and biaxial extension are generated in 3D-printed fluidic devices combined with active feedback control for particle manipulation in 3D. Flow fields are characterized using particle tracking velocimetry complemented by finite-element simulations for all flow geometries. Single colloidal particles (3.4 μm diameter) are confined in low viscosity solvent (1.0 mPa s) near the stagnation points of uniaxial and biaxial extensional flow for long times (≥10 min) using active feedback control. Trap stiffness is experimentally determined by analyzing the power spectral density of particle position fluctuations. We further demonstrate precise manipulation of colloidal particles along user-defined trajectories in three dimensions using automated flow control. Newtonian liquid droplets and GUVs are trapped and deformed in precisely controlled uniaxial and biaxial extensional flows, which is a new demonstration for 3D flow fields. Overall, this work extends flow-based manipulation of particles and droplets to three dimensions, thereby enabling quantitative analysis of colloids and soft materials in complex nonequilibrium flows.

Optimizing the size distribution of zinc borosilicate glass powder by organic solvent and tetradecylphosphonic based wet milling

Zinc borosilicate glass are crucial adhesive medium in modern electronic industry. However, it is still hard to prepare the zinc borosilicate glass with uniform particle size distribution. Herein, narrow particle size distribution and reduced hemispherical point temperature of zinc borosilicate glass was obtained by choosing low polarity, viscosity and surface tension organic solvent as well as surface modifier in the wet ball milling method. It is found that xylene, ethanol and isopropyl alcohol are good liquid medium for wet ball milling. Moreover, tetradecylphosphonic acid (TDPA) as a surface modifier could effectively reduce the formation of surface hydroxyl group in glass powder by the nucleophilic substitution reaction of the phosphonic acid group, showing superb anti-aggregation properties. Therefore, this work provides a general method for controlling particle size distribution of glass powder.

Inkjet printing of pixel arrays: droplet formation and pattern uniformity of a non-aqueous ink with tunable viscosity

Inkjet printing is a rapid and material-efficient process that is suitable for the fabrication of large-area microarrays from a range of optoelectronic materials. In order to ensure stable droplet formation and a uniform print image with very smooth surfaces, however, the ink properties such as viscosity and surface tension have to be precisely adjusted. In this study, a non-aqueous ink formulation is proposed whose viscosity can be conveniently adjusted by controlling the mixing ratio of propylene carbonate (PC) as the low-viscosity solvent and propylene glycol (PG) as the high-viscosity solvent. Using a combination of advanced imaging techniques, we show that raising the PG content from 20% to 80% increased the viscosity of the ink from 3.36 cP to 26.70 cP, resulting in stable droplet formation and a more evenly printed image. At a spacing of 5 dots/pixel, the roughness value decreased dramatically, from root mean square (RMS): 11.28 (20% PG) to RMS: 0.09 (80% PG). Alternatively, more homogeneous patterns (albeit with a rough surface) were also produced with the low-viscosity ink (20% PG) when a conditioned substrate with low surface energy and selective liquid repellency was used. With this we present a simple but effective strategy to improve droplet formation while obtaining highly uniform pixel arrays. The knowledge gained will be particularly useful for inkjet printing of pixel-patterned color conversion layers in devices such as organic light-emitting diodes (LEDs) and micro-LED displays.

Experimental solubility and thermodynamic modeling of nitric oxide absorption in low-viscosity DBU-based deep eutectic solvents

Developing absorbents with highly efficient nitric oxide (NO) absorption and desorption is very important for flue gas denitrification process. Toward this end, a class of DBU-based deep eutectic solvents (DESs) containing alkanones or azoles as functional HBDs for the capture of NO were synthesized in this work, with viscosities of only 7.71–45.57 mPa·s at 303.2 K. Solubilities of NO in these DESs were determined at temperatures from 303.2 to 333.2 K and pressures from zero to 1 bar. It was found that the absorbing abilities of the DESs increased with the increasing HBDs’ alkalinity. Impressively, these DBU-based DESs had remarkable larger absorption capacities than those reported DESs in the literature. According to the solubility curves of NO, chemical absorption was thought to occur accompanying with the physical one in the systems. Therefore, the reaction equilibrium thermodynamic model (RETM) was applied to model the experimental NO solubilities. The corresponding thermodynamic parameters for each system, such as the reaction equilibrium constant, Henry’s law constant, and the enthalpy change were also obtained to assess the NO absorption process in these DESs.

Microstructure analysis of Si/graphite composite anode during charge-discharge cycle for lithium-ion battery with tetraglyme- and sulfolane-based less volatile electrolyte

The microstructure of a composite anode of Si-alloy and graphite during charge-discharge tests was analyzed for a lithium-ion battery (LIB) with a less volatile electrolyte in order to clarify its degradation mechanism. An equimolar complex composed of tetraethylene glycol dimethyl ether and lithium bis(trifluoromethanesulfonyl)amide (Li(G4)TFSI) and a highly concentrated solution of sulfolane and LiTFSI (Li(SL)3TFSI) were used as the main Li conductors of the less volatile electrolyte. Also, low-viscosity solvents (propylene carbonate (PC), butylene carbonate (BC), and ethylene carbonate (EC)) were added to enhance the conductivity and increase the rate performance. The Li(SL)3TFSI-based electrolyte showed a sufficient rate performance with less amount of low-viscosity solvent compared to the Li(G4)TFSI-based electrolyte thanks to the high Li transportation number of Li(SL)3TFSI, which is a favorable feature for highly durable and less volatile electrolytes. The Li(G4)TFSI-45 wt.% PC and Li(SL)3TFSI-20 wt.% BC, which had respective volatilization temperatures of 378 K and 413 K, were incorporated into laminated cells consisting of a Si alloy/graphite anode and LiNixMnyCozO2 cathode. The cycle tests revealed that the discharge capacity of the cell with Li(SL)3TFSI-20 wt.% BC dropped rapidly during charge-discharge. The results of thickness measurement and scanning electron microscopy of the anodes after the cycle test indicated that the agglomerate structure of the Si-alloy, graphite, and poly(amide-imide) (PAI) binder was deteriorated by the volume change during the cycle test. Also, a solubility test of the PAI film and analysis of the Hansen solubility parameters of the film and solvent in the electrolyte suggested that the binder was likely to dissolve or swell in the Li(SL)3TFSI-20 wt.% BC solution, which would weaken the mechanical strength of the anode microstructure. Hence, to suppress the microstructure deterioration, we modified the chemical composition of the electrolyte to control the solubility of the binder. The replacement of BC with EC was effective to suppress the microstructural deterioration and then enhance the capacity retention during the cycle test.

Modern Bitumen Oil Mixture Models in Ashalchinsky Field with Low-Viscosity Solvent at Various Temperatures and Solvent Concentrations

The article analyzes the modern theory and practice of pipeline transport of bituminous oil together with low-viscosity solvent. In addition, a detailed analysis of the rheological models of non-Newtonian fluids is carried out, which establishes a number of assumptions on the rheology model selection algorithm currently in use (limited number of rheological models, variability in model coefficient assignment, etc.). Ways of their elimination are proposed. Dependencies for determination of the dynamic viscosity coefficient of binary oil mixtures are investigated. Calculation of the parameters of the bituminous oil mixture with solvent is considered. Complex experimental studies on rheology mixture models of bituminous oil and solvent on the example of the Ashalchinsky field (Russia, Tatarstan) in a wide range of temperatures and concentrations of the solvent are conducted. A two-dimensional field of rheological models of the oil mixture is constructed, which makes it possible to determine the rheological model of the pumped oil mixture depending on the solvent concentration and the temperature of the mixture. Formulas for forecasting the rheological properties of the oil mixture on the basis of statistical processing of the results of experimental studies are theoretically substantiated. It is proven that the viscosity of binary oil mixtures in the Newtonian fluid field should be determined by a modified Arrhenius equation. The proposed models with a high degree of accuracy describe the rheological properties of the oil mixture. It is shown that in the case of complex mixtures, not one rheological model should be applied, but their hierarchy should be established depending on the solvent concentration and temperature.

SPECTRAL-LUMINESCENT PROPERTIES OF A NEW BENZETHIAZOLE POLYMETHINE DYE

The absorption and fluorescence spectra of a new styryl derivative of thioflavin T tosylate 2-{(1E,3E)-4-[4-(dimethylamino)-2,6-dimethylphenyl]buta-1,3-dien-1-yl}- 3-ethyl-1,3-benzothiazolium-3 (Th-C23) in solvents of different polarity and viscosity, as well as when it is incorporated into the structure of amyloid fibrils
 and bovine serum albumin are investigated. A characteristic feature of the dye is an extremely low fluorescence quantum yield in low-viscosity solvents (10–4 in water), which, however, increases significantly in viscous solutions and when incorporated into the structure of proteins or amyloid fibrils. In the latter case,
 the quantum yield increases by 8х103 times. Based on experimental studies and quantum chemical calculations,
 it is shown that Th-C23 exhibits molecular rotor properties. An increase in the fluorescence quantum yield in viscous solutions and upon incorporation into biopolymers is the result of limiting the torsion rotation of molecular fragments, leading to fluorescence quenching. The long-wavelength position of the absorption spectrum and the fluorescence spectrum of the new dye in the red region of the spectrum (520 and 600 nm)
 makes it possible to use it as a fluorescent marker sensitive to the viscosity (hardness) of the microenvironment not only in vitro, but also in vivo.

Efficient and selective absorption of SO2 by low-viscosity matrine-based deep eutectic solvents

Designing excellent liquid absorbents with low viscosity for efficient and selective absorption of sulfur dioxide (SO2) from flue gas is important but still challenging. Herein, matrine-based binary deep eutectic solvents (DESs) were prepared by mixing matrine (Mat) with three different amides including N-methylformamide (MFA), N-ethylformamide (EFA), and N-methylacetamide (MAA). It is found that the viscosities of these three DESs were lower than 20 cP at room temperature, which is significantly lower than other previous DESs or ILs that have been reported. Moreover, the results of SO2 capture showed that the absorption rate of SO2 by the Mat-MFA (1:2) DES was very fast (<3 min) to achieve a relatively large absorption capacity (0.84 g/g at 293.2 K and 1 bar). Mat-MFA (1:2) DES also displayed very high selectivity (576) for the SO2/CO2 (10/90, v/v) mixture, which is higher than most of the liquid absorbents and solid adsorbents currently reported. Furthermore, breakthrough experiments verified the good separation performance of Mat-MFA (1:2) DES in capturing 2% SO2 in the mixture of SO2/N2 or SO2/CO2, respectively. The results illustrated that the features of low viscosity, fast absorption rate, and high selectivity of SO2 capture make the matrine-based DESs have great potential for flue gas desulfurization.

Thermally durable electrolyte for lithium-ion battery

For ensuring the safety of lithium-ion batteries (LIBs), we extensively investigated a composite electrolyte composed of a less volatile Li conductive electrolyte solution, silica (SiO2) particles, and fluorine-based binder as a thermally durable electrolyte. In this article, we review the roles of the electrolyte constituents. For the less volatile solution, we applied an equimolar complex of lithium bis(trifluoromethanesulfonyl)amide (LiTFSI) and tetraethylene glycol dimethyl ether (G4), Li(G4)TFSI, which was diluted with a low-viscosity solvent (propylene carbonate, PC) to enhance the ionic conductivity. The resultant electrolyte exhibited a favorable volatilization temperature higher than 373 K, and was applied to a 100-Wh-class laminated LIB. The cell generated neither fire nor smoke in a nail-penetration test, where the composite of SiO2 and fluorine-based binder had evidently covered the electrodes at the short-circuit region. This insulation phenomena effectively suppressed the joule heat generation and thereby kept the battery safe. One of the challenges with Li(G4)TFSI-based electrolytes is how to improve the durability during the charge and discharge cycles. The continuous decompositions of G4 and PC were a major reason for the growth of a solid-electrolyte interphase, which caused the capacity fade during charge-discharge cycles. We therefore replaced the G4-based liquid with a highly concentrated sulfolane-based liquid featuring a high Li+ transport number and a lower-viscosity solvent and found that it demonstrated a higher capacity retention after a charge-discharge cycle test.

Efficient Biomass Pretreatment Process Based on the Simple Reuse of a Low-Viscosity Ionic-Liquid Solvent System

Ionic liquids (ILs) are expensive, so it is necessary to reuse ILs; however, the reuse process is cumbersome as antisolvents are added and evaporated to regenerate ILs after each biomass pretreatment. Increasing the treatment capacity of biomass before regenerating ILs is desired; however, the high treatment capacity of biomass before IL regeneration and high lignin removal rate are a contradiction in terms. In this paper, a solution was proposed that includes pretreating biomass with a binary system composed of low-viscosity IL 1-ethyl-3-methylimidazole tetrafluoroborate ([Emim][BF4]) and l-arginine (Arg). It was shown that Arg could promote lignin dissolution and inhibit cellulose degradation in [Emim][BF4]. The system could be reused just by vacuum filtration after pretreatment without using antisolvents. After using [Emim][BF4]–Arg five times, the cumulative treatment capacity of corn straw reached 20.55%, while the total removal rate of lignin (84.94%) and the total yield of cellulose (93.23%) remained high. This method is of great significance for the industrial application of biomass pretreatment using ILs.

Solidification/stabilization (S/S) of high viscosity organics in geopolymers

This research contributes to nuclear waste management by proposing a simple treatment route for high viscosity (HV) organics (oils and greases). These are currently without an industrial solution, because they are not directly pourable into a cementation matrix. Their solidification/stabilization (S/S) into geopolymers (GP) is investigated. Incorporation is achieved by assembling the HV organics (a model oil MO, an industrial oil IO or a grease G) with a low viscosity (LV) solvent, either dodecane (C12) or a mix of tributylphosphate (TBP)/C12, prior to mixing with the fresh GP.First, the minimal solvent amount is determined to achieve sufficient fluidity of the HV oil or grease mix. Two different criteria are used, one for the Newtonian oils and the other for the non-Newtonian grease. Secondly, the immobilization of 20%vol of assembled mix is performed into a GP paste or mortar. The organics bleeding, the GP setting, the rheological properties of the mix, and the mechanical performance at 28 days endogenous curing are assessed. The morphology of the oil or grease emulsion inside the hardened GP mortar is determined by 2D SEM observations and 3D quantitative X Ray micro-computed tomography. The efficiency of the immobilization is proven by cross analyzing these properties. In particular, a minimal compressive strength of 25.4 MPa +/− 4.6 is achieved for a GP mortar immobilizing 20%vol HVG assembled with TBP/C12; it corresponds to an emulsion made of 12.9%vol droplets in the 10–480 µm size range, and 7.1%vol smaller than 10 µm, without organics bleeding.

Effectively inhibiting the degradation of chitin during extraction from crustacean waste via a novel deep eutectic solvent aqueous solution

This study proposed a feasible route for effectively inhibiting degradation of chitin by introducing a novel low-viscosity gluconic acid-based deep eutectic solvents (DESs) aqueous solution. Under the optimal extraction conditions, a high-quality chitin with molecular weight of 3.75 × 105 Da, purity of 94.5 % and yield of 79.1 % was obtained from crab shell. The maximum yield and molecular weight of chitin extracted by DESs were 1.37 times and 3.02 times higher than traditional acid/alkali method, respectively. DESs showed satisfactory recycling performance and the chitin purity could still reach 82.6 % after reusing DESs four times. Mechanism analysis confirmed that introduction of amino acids enhanced the interactions in the DESs system. The main reason for inhibiting degradation of chitin was that the reagents mainly acted on calcium carbonate and protein, without appreciable effect on the structure of chitin. This study provided a green and effective utilization strategy for crustacean waste based on multifunctional DESs systems.

Effect of Solvents on the Stability of Water-in-Bitumen Emulsions

In this study, the role of the solvent in stabilizing water-in-oil emulsions was investigated below and above the onset of asphaltene precipitation. Two Western Canadian bitumens with significantly different emulsion-stabilizing capacities were evaluated. Water-in-asphaltene/solvent and water-in-diluted bitumen emulsions were prepared with extracted n-heptane-insoluble asphaltenes, toluene, and an alkane (n-pentane, n-heptane, n-decane, n-hexadecane, and cyclohexane). The organic phases were prepared with and without removing any precipitated asphaltenes. The stability of the settled emulsions was assessed in terms of the free water evolved after treatment with heating and centrifugation. Factors that could contribute to emulsion stability were measured including the drop size distribution, water volume fraction, and asphaltene mass surface coverage of the settled emulsions. Surface pressure isotherms of asphaltene films were measured to assess irreversible interfacial film formation in each solvent. In precipitate-free emulsions, emulsion stability was found to increase significantly at the onset of precipitation. The increase in stability was attributed to the increased irreversible adsorption of asphaltenes at the interface as their solubility in the oil phase decreased. Most of the emulsions became less stable at high n-alkane contents as more asphaltenes were precipitated out of solution and the supply of soluble emulsion stabilizers was depleted. The results demonstrate that oils at conditions near the onset of asphaltene precipitation are more likely to experience problematic emulsions. However, it was found that, with low-viscosity solvents, this effect may be mitigated by the presence of the precipitated particles in the emulsion.

Nanostructure in amino acid ionic molecular hybrid solvents

Choline amino acid ionic liquids ([Ch][AA]ILs) have shown outstanding capacity for extraction and biomass pre-treatment but their very high viscosity renders them difficult to handle and inhibits their large-scale application. As a result, [Ch][AA]ILs are commonly mixed with a low-viscosity molecular solvent such as water to form hybrid solvents, which preserves the favourable characteristics of ILs while enhancing physical properties. Here we investigate the structure of binary mixtures of choline lysinate and phenylalaninate with water and primary alcohols. Contrast-variation neutron diffraction and computational modelling shows the nanostructure of both [Ch][AA]ILs can be engineered by mixing with alcohols up to high concentrations, and that the abundance of hydrogen-bond donors is a critical determinant of the overall liquid structure. This provides a new strategy to engineer and fine tune solvent nanostructure for the design of application-specific, biofriendly hybrid solvent systems.

Local Lithium-Ion Transport of a Ternary Sulfolane-Lithium Bis(trifluoromethanesulfonyl)amide-Carbonate Electrolyte: Experimental and First-Principles Molecular Dynamics Analysis toward Quasi-Solid-State Lithium-Ion Battery

The ion coordination and local ion transport of the ternary electrolyte containing sulfolane (SL), lithium bis(trifluoromethanesulfonyl)amide (LiTFSA), and a carbonate solvent were investigated by combining the electrochemical measurement and first-principles molecular dynamics (FPMD) simulation. Li(SL)3TFSA solution with the low-viscosity carbonate solvents, propylene carbonate (PC) and butylene carbonate (BC) was quasi-solidified by nanosized SiO2 and PTFE binder. Electrochemical impedance spectroscopy revealed that the quasi-solidified electrolyte sheets exhibited the Li+ transport number of 0.5, which was higher than that of Li(G4)TFSA containing PC and the conventional organic liquid electrolyte. The higher Li+ transport number contributed to an enhanced discharge capacity of the LIB at a high rate, and the LIB with Li(SL)3TFSA-PC and Li(SL)3TFSA-BC based electrolyte exhibited higher capacity retention in cycle test compared with Li(G4)TFSA-PC. The FPMD analysis revealed that a bridging coordination by SL and TFSA, where a single SL or TFSA coordinates two Li+, was observed even under coexistence with the carbonate solvent. It was also confirmed that some Li+ tend to transfer independently to the other molecules/anions via the bridging coordination, leading to the high Li+ transport number. In conclusion, the composition design of the electrolyte to keep the bridging coordination is desirable for a high Li+ transport number and superior LIB performances.