Search Results (121)

For various applications, particularly in battery technology, there is a significant demand for uniform, high-quality lithium or lithium-coated materials. The use of electrodeposition techniques to obtain such materials has not proven practical or economical due to the low solubility of most lithium salts in suitable solvents. In this study, we propose efficient lithium electrodeposition processes and baths that can be operated at low temperatures and relatively low costs. We utilized organic solvents such as dimethyl acetamide (DMA), dimethylforamide (DMF), and dimethyl sulfoxide (DMSO), as well as a mixture of DMSO and ionic liquid [1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide BMIMTFSI]. Lithium salts such as LiCl, Li₂CO₃, and LiNO₃ were tested. Lithium metal was deposited on copper substrates at different temperatures and selected current densities within an argon-filled glovebox using a DC power source or a PARSTAT-4000A potentiostat. Cyclic voltammetry (CV) was employed to determine and compare the deposition processes. The obtained deposits were analyzed through visual inspection (photography) and scanning electron microscopy (SEM). Chemical analysis (ICP-OES) and XRD confirmed the presence of lithium and occasionally lithium hydroxide in the deposits. The best results were achieved with the deposition of lithium from DMSO-LiNO₃ and DMSO-BMIMTFSI-LiNO₃ systems. Full article

Carbon dioxide, the primary greenhouse gas responsible for global warming, represents today a critical environmental challenge for humans. Mitigating CO₂ emissions and other greenhouse gases is a pressing global concern. The primary goal of this study is to investigate the potential of particular ionic liquids (ILs) in capturing CO₂ for the sweetening of natural and other gases. The solubility of CO₂ was measured in three distinct ILs, which shared a common anion (triflate, TfO) but differed in their cations. The selected ionic liquids were {1-butyl-3-methylimidazolium triflate [BMIM][TfO], 1-butyl-1-methylpyrrolidinium triflate [BMP][TfO], and 1-butyl-4-methylpyridium triflate [MBPY][TfO]}. The solvents were screened based on results from a molecular computational study that predicted low CO₂ Henry’s Law constants. Solubility measurements were conducted at 303.15 K, 323.15 K, and 343.15 K and pressures up to 1.5 MPa using a gravimetric microbalance (IGA-003). The CO₂ experimental results were modeled using the Peng–Robinson Equation of state with three mixing rules: van der Waals one (vdWI), van der Waals two (vdWII), and the non-random two-liquid (NRTL) Wong–Sandler (WS) mixing rule. For the three ILs, the NRTL-WS mixing rule regressed the data with the lowest average deviation percentage of 1.24%. The three solvents had similar alkyl chains but slightly different polarities. [MBPY][TfO], with the largest size, exhibited the highest CO₂ solubility at all three temperatures. Calculation of its relative polarity descriptor (N) shows it was the least polar of the three ILs. Conversely, [BMP][TfO] showed the highest Henry’s Law constant (lowest solubility) across the studied temperature range. Comparing the results to published data, the study concludes that triflate-based ionic liquids with three fluorine atoms had lower capacity for CO₂ compared to bis(trifluoromethylsulfonyl) imide (Tf2N)-based ionic liquids with six fluorine atoms. Additionally, the study provided data on the enthalpy and entropy of absorption. A final comparison shows that the ILs had a lower CO₂ capacity than Selexol, a solvent widely used in commercial carbon capture operations. Compared to other ILs, the results confirm that the type of anion had a more significant impact on solubility than the cation. Full article

New chiral salen-based organic salts were synthesised and evaluated for their antibacterial activity against Serratia fonticola, Escherichia coli, and Enterobacter cloacae. Their structures and physicochemical properties, namely their specific rotation, melting point, thermal stability, and antibacterial efficacy, including minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), were determined. The synergy between chiral organic salts and bacteriophages was also demonstrated. [(RR)Sal.5C1.PhIM][Cl], [(RR)Sal.5C1.PhIM][BF₄], and [(RR)Sal.5C1.Pyr][OTf] had the lowest MIC values (from 500 mg mL⁻¹ for S. fonticola strain KKP 3685 to 2000 mg mL⁻¹ for E. cloacae strain KKP 3692), while the highest MICs (>4000 mg mL⁻¹) were observed for [(RR)Sal.5C1.Pyr][OTf] and [(RR)Sal.5C1.PhIM][NTf₂] against E. cloacae strain KKP 3692. The impact of the tested compounds on phage activity was strain-specific. A synergistic effect of [(RR)Sal.5C1.PhIM][BF₄] at 0.5 mg mL⁻¹ in microcultures with Escherichia phage KKP 3710 (at MOI of 10 and 100) on the complete inhibition of the growth of E. coli strain KKP 3688 was observed. The combination of [(RR)Sal.5C1.PhIM])][OTf] at 1 mg mL⁻¹ with the addition of phages (at each MOI) and at 0.5 mg mL⁻¹ and MOI = 100 completely inhibited the growth of E. coli strain KKP 3688. Moreover, [(RR)Sal.5C1.PhIM])][OTf] at 1 mg mL⁻¹ and 0.5 mg mL⁻¹, when combined with Enterobacter phage KKP 3716, inhibited the growth of E. cloacae strain KKP 3692 slightly more effectively than the compound alone at the same concentrations. These results suggest that combining our antibacterial agents can reduce chemical compound concentrations, with effects depending on the bacteria. Full article

Bacterial cellulose (BC) is a highly pure and crystalline cellulose produced via bacterial fermentation. However, due to its chemical structure made of strong hydrogen bonds and its high molecular weight, BC can neither be melted nor dissolved by common solvents. Therefore, processing BC implies the use of very strong, often toxic and dangerous chemicals. In this study, we proved a green method to produce electrospun BC fibers by testing different ionic liquids (ILs), namely, 1-butyl-3-methylimidazolium acetate (BmimAc), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EmimTFSI) and 1-ethyl-3-methylimidazolium dicyanamide (EmimDCA), either individually or as binary mixtures. Moreover, γ-valerolactone (GVL) was tested as a co-solvent derived from renewable sources to replace dimethyl sulfoxide (DMSO), aimed at making the viscosity of the cellulose solutions suitable for electrospinning. A BmimAc and BmimAc/EmimTFSI (1:1 w/w) mixture could dissolve BC up to 3 w%. GVL was successfully applied in combination with BmimAc as an alternative to DMSO. By optimizing the electrospinning parameters, meshes of continuous BC fibers, with average diameters ~0.5 μm, were produced, showing well-defined pore structures and higher water absorption capacity than pristine BC. The results demonstrated that BC could be dissolved and electrospun via a BmimAc/GVL solvent system, obtaining ultrafine fibers with defined morphology, thus suggesting possible greener methods for cellulose processing. Full article

The advent of the lithium-ion batteries (LIBs) has transformed the energy storage field, leading to significant advances in electronics and electric vehicles, which continuously demand more and more performant devices. However, commercial LIB systems are still far from satisfying applications operating in arduous conditions, such as temperatures exceeding 100 °C. For instance, safety issues, materials degradation, and toxic stem development, related to volatile, flammable organic electrolytes, and thermally unstable salts (LiPF₆), limit the operative temperature of conventional lithium-ion batteries, which only occasionally can exceed 50–60 °C. To overcome this highly challenging drawback, the present study proposes advanced electrolyte technologies based on innovative, safer fluids such as ionic liquids (ILs). Among the IL families, we have selected ionic liquids based on tetrabutylphosphonium and 1-ethyl-3-methyl-imidazolium cations, coupled with per(fluoroalkylsulfonyl)imide anions, for standing out because of their remarkable thermal robustness. The thermal behaviour as well as the ion transport properties and electrochemical stability were investigated even in the presence of the lithium bis(trifluoromethylsulfonyl)imide salt. Conductivity measurements revealed very interesting ion transport properties already at 50 °C, with ion conduction values ranging from 10⁻³ and 10⁻² S cm⁻¹ levelled at 100 °C. Thermal robustness exceeding 150 °C was detected, in combination with anodic stability above 4.5 V at 100 °C. Preliminary cycling tests run on Li/LiFePO₄ cells at 100 °C revealed promising performance, i.e., more than 94% of the theoretical capacity was delivered at a current rate of 0.5C. The obtained results make these innovative electrolyte formulations very promising candidates for high-temperature LIB applications and advanced energy storage systems. Full article

1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI.NTf₂) is a hydrophobic ionic liquid with potential antibacterial properties for dental materials. This study aimed to (1) incorporate different mass fractions of BMI.NTf₂ into a dental adhesive and (2) assess its impact on physical and chemical properties. Adhesive resins were prepared with 1 (G_1%), 2.5 (G_2.5%), and 5 wt.% (G_5%) BMI.NTf₂, with a control group (G_CTRL) lacking the ionic liquid. Evaluations included polymerization kinetics, degree of conversion (DC), softening in solvent (ΔKHN%), and ultimate tensile strength (UTS). Groups with BMI.NTf₂ showed accelerated polymerization kinetics, with G_5% achieving a higher DC and ΔKHN% compared to G_CTRL (p < 0.05). Lower concentrations (1% and 2.5%) did not affect ΔKHN%, and no significant differences were found in UTS across groups (p > 0.05). Notably, 2.5 wt.% of BMI.NTf₂ increased the DC without affecting other properties, indicating optimal polymerization rates and handling characteristics. These results support the development of BMI.NTf₂-based antibacterial adhesives that may assist in preventing secondary caries in restorative dentistry. Full article

Excited state intramolecular proton transfer (ESIPT) within molecules in solvents plays important roles in photo-chemistry and photo-biology. Herein, the influence of 1-ethyl-3-methyl-imidazolium bis (trifluoromethylsulfonyl) imide ([EMIm][NTf₂]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF₆]) on the ESIPT of 4′-N,N-diethylamino-3-hydroxyflavone (DEAHF) was explored. The density functional theory and time-dependent density functional theory methodologies were used. The calculated fluorescence spectrum reveals that the fluorescence peaks of DEAHF in [EMIm][NTf₂] and [BMIm][PF₆] originate from the emission of N* and T* forms. The structure’s optimization, infrared spectra, non-covalent interactions and the scanning of potential energy curves collectively demonstrate that the ESIPT of DEAHF likely happen more in [EMIm][NTf₂] than in [BMIm][PF₆]. The solvation effects in [BMIm][PF₆] exhibit greater prominence compared to those in [EMIm][NTf₂], as evidenced by the free energy curve. The alterations in dipole moment indicate a substantial solvation relaxation during the ESIPT processes. Our aforementioned research offers backing for the advancement of novel fluorescent probes. Full article

This research addresses the critical challenge of CO₂ capture by exploring innovative ways to avoid ethane (C₂H₆) co-absorption in natural gas sweetening operations. The solubility of Ethane (C₂H₆) was measured in three ionic liquids (ILs) with similar anions, 1-decyl-3-methyl imidazolium bis (trifluoro methylsulfonyl imide) [IL-1], 1-hexadecyl-3-methylimidazolium bis (trifluoro methylsulfonyl imide) [IL-2], and triethytetra-decyl ammonium bis (trifluoromethylsulfonyl imide) [IL-3]. The solubility experiments were investigated at 303.15 K and 343.15 K with pressures reaching 1.2 MPa. Among the ILs, [IL-2] exhibited the highest ethane absorption capacity due to its extended alkyl chain. The Peng-Robinson equation of state (PR-EoS) and three (3) distinct mixing rules provided robust correlations for the solubility data. Results demonstrate the inferior performance of [IL-1], [IL-2], and [IL-3] compared to Selexol/Genosorb 1753. The selectivity of Ethane (C₂H₆) over CO₂ was determined, with the overall selectivity ranking as follows: [IL-1] > [IL-3] > [IL-2]. A comparison of these selectivity values with published IL data indicated that these three ILs are most effective when used in applications targeting CO₂ capture in the absence of Ethane (C₂H₆), such as in the case of flue gas. They will most probably be used with an amine blend. Additionally, the Enthalpy and entropy of absorption provided valuable insights, demonstrating Ethane’s weaker interactions and lower solubility than CO₂. These findings emphasize the critical role of IL structure in determining ethane solubility and highlight the potential of customized ILs for optimizing gas-separation processes. Full article

Following the successful utilization of various 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids (ILs) as effective solvents in the extraction of ethanol, 1-propanol, and 2-propanol from water, we conducted experiments to determine the liquid–liquid equilibria data for the ternary mixture comprising water, ethanol, and 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([dmim][Tf2N]) at temperatures of 283.2 K, 303.2 K, and 323.2 K under atmospheric pressure. The thermodynamic parameters for both ternary mixtures were calculated using the non-random two-liquid (NRTL) and universal quasichemical (UNIQUAC) models, yielding favorable results across all investigated conditions (rmsd < 0.65%). Subsequently, we explored the efficiency of [dmim][Tf2N] in separating azeotropic mixtures by analyzing the distribution coefficient and selectivity (K₂ and S greater than 1 in all cases, with maximum values of 3.551 and 10.878, respectively). Comparative assessments were made against the performance of various 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ILs and alcohols. The findings underscore the promising capabilities of [dmim][Tf2N] in achieving effective separation, providing valuable insights for potential applications in liquid–liquid extraction processes. Full article

The electrochemical properties of the hydrophobic room-temperature ionic liquid 1-propyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide (PMMIm(TFSI)) were investigated, for the first time, using an electrochemical double-layer capacitor-mimicking cell containing two identical-sized micro–mesoporous molybdenum carbide-derived carbon electrodes (MMP-C(Mo₂C)), by applying cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Surprisingly, despite the substitution of the slightly acidic hydrogen atom with a methyl group at the carbon atom located between two nitrogen atoms in the imidazolium cation, the EIS and CV measurements demonstrated that PMMIm(TFSI) began to decompose electrochemically at the same cell potential (ΔE) as 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIm(BF₄)), specifically at ΔE = 2.75 V. However, the CV and EIS data indicated that PMMIm(TFSI) decomposed with a significantly lower intensity than EMIm(BF₄). Therefore, we believe that the use of PMMIm(TFSI) as the electrolyte will enable the construction of safer supercapacitors that can tolerate short periods of over-polarization up to ΔE = 4.0 V. However, when the ΔE ≤ 3.2 V was applied, EMIm(BF₄) offered higher maximum power compared to PMMIm(TFSI). We found that the calculated maximum gravimetric power precisely describes the maximum ΔE applicable for a supercapacitor candidate. Full article

The extraction of lanthanides(III) from aqueous nitric acid solutions with novel unsymmetrical diglycolamide extactant, N,N′-dimethyl-N,N′-dicyclohexyldiglycolamide (DMDCHDGA) into bis(trifluoromethylsulfoyl)imide-based ionic liquids (ILs), namely 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C₄mim][Tf₂N]), 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C₈mim][Tf₂N]), benzyltriethylammonium bis(trifluoromethylsulfonyl)imide ([N_222Bn][Tf₂N]) methyltrioctylammonium bis(trifluoromethylsulfonyl)imide ([N₁₈₈₈][Tf₂N]), and their mixtures with molecular organic diluent 1,2-dichloroethane (DCE), is studied. DMDCHDGA has been shown to interact with components of the IL [C₄mim][Tf₂N]. The effect of HNO₃ concentration in the aqueous phase on the extraction of Ln(III) ions is studied. The stoichiometry of the extracted complexes is determined, and the mechanism of Ln(III) extraction in a system with [C₄mim][Tf₂N] is discussed. It is shown that the efficiency and intragroup selectivity of the extraction of Ln(III) ions with DMDCHDGA into [C₄mim][Tf₂N] is significantly higher than when using its symmetric analog TODGA. Full article

Ionic Liquids (ILs) are composed of ions, usually an organic cation with an organic or inorganic anion, with a melting point below 100 °C and in most cases below room temperature. These compounds exhibit important and characteristic properties such as high ionic conductivity, good thermal and electrochemical stability and low toxicity and flammability. Subsequently, ILs have been studied as promising substitutes for conventional electrolytes for electrochemical applications, both as bulk liquids or confined in polymer matrices, commonly known as ionogels, which have the advantages of not leaking and enhancing safety and manipulation during device assembly. For this work, the ionogel of the IL 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C₂C₁Im][TFSI]) was synthesized by the polymerization of Tetramethyl orthosilicate (TMOS) and Dimethyldimethoxysilane (DMDMS). Thermal analyses of the pure ionic liquid and electrochemical response of the ionogel were studied in comparison with the corresponding bulk IL by using differential scanning calorimetry (DSC), thermogravimetry (TGA) and broad-band dielectric spectroscopy (BBDS), respectively. Full article

The molar heat capacity of 1,4-bis(3-methylimidazolium-1-yl)butane bis(trifluoromethylsulfonyl)imide dicationic ionic compound ([C₄(MIm)₂][NTf₂]₂) has been studied over the temperature range from 6 to 350 K by adiabatic calorimetry. In the above temperature interval, this compound has been found to form crystal, liquid, and supercooled liquid. For [C₄(MIm)₂][NTf₂]₂, the temperature of fusion T°_fus = (337.88 ± 0.01) K has been determined by the fractional melting experiments, the enthalpy of fusion Δ_fusH° = (52.79 ± 0.28) kJ mol⁻¹ has been measured using the calorimetric method of continuous energy input, and the entropy of fusion Δ_fusS° = (156.2 ± 1.7) J K⁻¹ mol⁻¹ has also been evaluated. The standard thermodynamic functions of the studied dicationic ionic compound, namely, the heat capacity C_p°(T), the enthalpy [H°(T) − H°(0)], the entropy S°(T) and the Gibbs free energy [G°(T) − H°(0)] have been calculated on the basis of the experimental data for the temperature range up to 350 K. The results have been discussed and compared with those available in the literature and in the NIST Ionic Liquids Database (ILThermo) for monocationic ionic compounds. Full article

This study delves into the necessity of mitigating carbon dioxide (CO₂) emissions, focusing on effective capture methods to combat global warming by investigating the solubility of CO₂ in three ionic liquids (ILs), 1-Decyl-3-MethylimidazoliumBis (Trifluromethylsulfonyl Imide) [IL1], 1-Hexadecyl-3-Methyl imidazoliumBis (Trifluromethylsulfonyl Imide) [IL2] and Triethytetradecyl Ammonium Bis (Trifluromethylsulfonyl Imide) [IL3]. Solubility experiments were conducted at (30, 50 and 70) °C with pressures up to 1.5 MPa. The research shows [IL2] as the superior candidate for CO₂ capture, with its longer alkyl chain, and is confirmed by its lower Henry’s Law constant. Utilizing the Peng Robinson equation of state, the study correlates well with the solubility measurements using three mixing rules. The study reveals promising results for IL1, IL2 and IL3 surpassing all other published ionic liquids including Selexol/Genesorb 1753, except for 1-Methyl-3-octylimidazolium bis(trifluoromethylsulfonyl)imide. Insights into the enthalpy and entropy of absorption underscore the significant impact of IL structure on CO₂ solubility, emphasizing the potential of tailored ILs for advanced carbon capture strategies. In summary, this research highlights [IL2] as the optimal choice for CO₂ capture, offering valuable contributions to the ongoing efforts in combating climate change. Full article

All-solid-state battery (ASSB) technology is a new energy system that reduces the safety concerns and improves the battery performance of conventional lithium-ion batteries (LIB). The increasing demand for such new energy systems makes the transition from laboratory scale production of ASSB components to larger scale essential. Therefore, this study investigates the dry extrusion of poly(ethylene oxide):lithium bis (trifluoromethylsulfonyl)imide (PEO:LiTFSI) all-solid-state electrolytes at a ratio of 20:1 (EO:Li). We investigated the influence of different extruder setups on the product quality. For this purpose, different screw designs consisting of conveying, kneading and mixing elements are evaluated. To do so, a completely dry and solvent-free production of PEO:LiTFSI electrolytes using a co-rotating, intermeshing, twin-screw extruder under an inert condition was successfully carried out. The experiments showed that the screw design consisting of kneading elements gives the best results in terms of process stability and homogeneous mixing of the electrolyte components. Electrochemical impedance spectroscopy was used to determine the lithium-ion conductivity. All electrolytes produced had an ionic conductivity (σ_ionic) of (1.1–1.8) × 10⁻⁴ S cm⁻¹ at 80 °C. Full article