Ionic/electronic conductivity regulation of n-type polyoxadiazole lithium sulfonate conductive polymer binders for high-performance silicon microparticle anodes

Low-cost silicon microparticles(SiMP),as a substitute for nanostructured silicon,easily suffer from cracks and fractured during the electrochemical cycle.A novel n-type conductive polymer binder with excellent electronic and ionic conductivities as well as good adhesion,has been successfully designed and applied for high-performance SiMP anodes in lithium-ion batteries to address this problem.Its unique features are attributed to the stro ng electron-withdrawing oxadiazole ring structure with sulfonate polar groups.The combination of rigid and flexible components in the polymer ensures its good mechanical strength and ductility,which is beneficial to suppress the expansion and contraction of SiMP s during the charge/discharge process.By fine-tuning the monomer ratio,the conjugation and sulfonation degrees of the polymer can be precisely controlled to regulate its ionic and electronic conductivities,which has been systematically analyzed with the help of an electrochemical test method,filling in the gap on the conductivity measurement of the polymer in the doping state.The experimental results indicate that the cell with the developed n-type polymer binder and SiMP(~0.5 μm) anodes achieves much better cycling performance than traditional non-conductive binders.It has been considered that the initial capacity of the SiMP anode is controlled by the synergetic effect of ionic and electronic conductivity of the binder,and the capacity retention mainly depends on its electronic conductivity when the ionic conductivity is sufficient.It is worth noting that the fundamental research of this wo rk is also applicable to other battery systems using conductive polymers in order to achieve high energy density,broadening their practical applications.     

The preparation of ionic liquid based iron phosphate/CNTs composite via microwave radiation for hydrogen evolution reaction and oxygen evolution reaction

Water electrolysis is a promising method for hydrogen production, so the preparation of low-cost and efficient electrocatalysts with a quick and simple procedure is crucial. Herein, iron phosphate (Fe₇(PO₄)₆) was prepared via microwave radiation using ionic liquid (IL) as iron and phosphorus dual-source. This method is simple and rapid, and the product can be directly used as electrocatalysts without further treatment. The experimental results show that the IL can influence the morphology and electrocatalytic performance. Moreover, the addition of carbon nanotubes (CNTs) is favorable for formation of iron phosphate nanoparticles to improve the catalytic activities. As hydrogen evolution reaction (HER) catalyst, this iron phosphate/CNTs exhibits an onset overpotential of 120 mV, Tafel slope of 32.9 mV dec^-1, and current densities of 10 mA cm⁻² at overpotential of 185 mV. Then, it obtains a good activity for oxygen evolution reaction (OER) with a low onset potential of 1.48 V, Tafel slope of 73.3 mV dec^-1, and it only needs an overpotential of 300 mV to drive the 10 mA cm⁻². This bifunctional catalyst also shows good durability for HER and OER. This microwave-assisted method provides an outstanding strategy to prepare iron phosphate in a simple and fast process with good catalytic performance for water splitting.     

Metal Sulfide Nanoparticle Synthesis with Ionic Liquids – State of the Art and Future Perspectives

Metal sulfides are among the most promising materials for a wide variety of technologically relevant applications ranging from energy to environment and beyond. Incidentally, ionic liquids (ILs) have been among the top research subjects for the same applications and also for inorganic materials synthesis. As a result, the exploitation of the peculiar properties of ILs for metal sulfide synthesis could provide attractive new avenues for the generation of new, highly specific metal sulfides for numerous applications. This article therefore describes current developments in metal sulfide nanoparticle synthesis as exemplified by a number of highlight examples. Moreover, the article demonstrates how ILs have been used in metal sulfide synthesis and discusses the benefits of using ILs over more traditional approaches. Finally, the article demonstrates some technological challenges and how ILs could be used to further advance the production and specific property engineering of metal sulfide nanomaterials, again based on a number of selected examples.     

Applications of single-drop microextraction in analytical chemistry: A review

Single-drop microextraction (SDME) has been recognized as one of the simple miniaturized sample preparation tools for the isolation and preconcentration of several analytes from a complex sample matrix. In this review, we explored the applications of SDME coupled with various analytical techniques (spectroscopy, chromatography, and mass spectrometry) for the analysis of organic molecules, inorganic ions, and biomolecules from various sample matrices including food, environmental, clinical, pharmaceutical, and industrial samples. Also, it summarizes the use of nanoparticles in SDME combined with various analytical tools for the rapid analysis of several trace-level target analytes. An overview of ionic liquids, deep eutectic solvents, and SUPRAS, which improved the selectivity and sensitivity of various analytical techniques toward several analytes, as promising extracting solvent systems in SDME is also included. Finally, discussed the impressive analytical features and future perspectives of SDME in this review article.     

New polymer electrolyte membrane for medium-temperature fuel cell applications based on cross-linked polyimide Matrimid and hydrophobic protic ionic liquid

New hydrophobic protic ionic liquid, 2-butylaminoimidazolinium bis(trifluoromethylsulfonyl)imide (BAIM-TFSI), has been synthesized. The ionic liquid showed good thermal stability to at least 350 °C. The conductivity of BAIM-TFSI determined by electrochemical impedance method was found to be 5.6 × 10^?2 S/cm at 140 °C. Homogeneous composite films based on commercial polyimide (PI) Matrimid and BAIM-TFSI containing 30–60 wt% of ionic liquid were prepared by casting from methylene chloride solutions. Thermogravimetric analysis data indicated an excellent thermal stability of PI/BAIM-TFSI composites and thermal degradation points in the temperature range 377 °C–397 °C. The addition of ionic liquid up to 50 wt% in PI films does not lead to any significant deterioration of the tensile strength of the polymer. The dynamic mechanical analysis results indicated both an increase of storage modulus E′ of PI/BAIM-TFSI composites at room temperature and a significant E′ decrease with temperature compared with the neat polymer. The cross-linking of the PI with polyetheramine Jeffamine D-400 allowed to prepare PI/Jeffamine/BAIM-TFSI (50%) membrane with E′ value of 300 MPa at 130 °C. The ionic conductivity of this cross-linked composite membrane reached the level of 10^?2 S/cm at 130 °C, suggesting, therefore, its potential use in medium-temperature fuel cells operating in water-free conditions.     

Versatile ligands for high-performance liquid chromatography: An overview of ionic liquid-functionalized stationary phases

Ionic liquids (ILs), a class of unique substances composed purely by cation and anions, are renowned for their fascinating physical and chemical properties, such as negligible volatility, high dissolution power, high thermal stability, tunable structure and miscibility. They are enjoying ever-growing applications in a great diversity of disciplines.     

Mixing and decomposition behavior of {[4bmpy][Tf2N] + [emim][EtSO4]} and {[4bmpy][Tf2N] + [emim][TFES]} ionic liquid mixtures

Mixing ionic liquids (ILs) has been revealed as a useful way to finely tune the properties of IL-based solvents. The scarce available studies on IL mixtures have shown a quasi-ideal behavior of their physical properties. In this work, we have performed a thermophysical characterization of two binary IL mixtures, namely {4-methyl-N-butylpyridinium bis(trifluoromethylsulfonyl)imide ([4bmpy][Tf₂N]) + 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO₄])} and {[4bmpy][Tf₂N] + 1-ethyl-3-methylimidazolium 1,1,2,2-tetrafluoroethanesulfonate [emim][TFES]}. Both binary IL mixtures have been recently proposed as promising solvents in the (liquid + liquid) extraction of aromatic hydrocarbons from mixtures with alkanes. Densities, viscosities, refractive indices, thermal stability, and specific heats of the {[4bmpy][Tf₂N] + [emim][EtSO₄]} and {[4bmpy][Tf₂N] + [emim][TFES]} IL mixtures have been measured as a function of both temperature and composition. Dynamic viscosities, refractive indices, and thermal stability of the {[4bmpy][Tf₂N] + [emim][EtSO₄]} mixture have exhibited strong deviations from the ideality, in contrast with the quasi-ideal properties of the {[4bmpy][Tf₂N] + [emim][TFES]} mixture and the behavior of the imidazolium and pyridinium-based IL mixtures studied hitherto. The reliability of predictive methods of the thermophysical properties of the mixtures has also been evaluated.     

The influence of 1-butyl-3-methyl-imidazolium bromide on the partitioning of l-tyrosine within the {polyethylene glycol 600 + potassium citrate} aqueous biphasic system at T = 298.15 K

Partitioning in aqueous biphasic systems (ABS) is widely recognized today as a rapid, gentle, and highly efficient technique for the separation of soluble as well as particulate biomaterials. This technique has gained increasing attention as the separation method of choice in biotechnology. In recent years, a new approach has been proposed based on the use of ionic liquids (ILs) as adjuvants for the separation and purification of bio-molecules using polymer-based ABS. In this regard, the influence of IL 1-butyl-3-methylimidazolium bromide ([C₄mim]Br) on the phase behavior and extraction capability of {PEG 600 + tri-potassium citrate (K₃C₆H₅O₇)} ABS for l-tyrosine (Tyr) is investigated here. For this purpose, phase diagrams and the liquid–liquid equilibrium (LLE) data for the {PEG 600 + K₃C₆H₅O₇} ABS with the addition of small quantities of IL were determined at T = 298.15 K. It was found that, for the studied polymer-based ABS, the addition of 5 wt% of [C₄mim]Br to ABS caused the expansion of two-phase area in the salt-rich region; while, for the PEG-rich region no change was observed. The partition coefficients of l-tyrosine (K_Tyr) within the studied system were determined at T = 298.15 K. The results obtained indicate that the addition of small quantities of [C₄mim]Br to the {PEG 600 + K₃C₆H₅O₇} ABS could enhance the extraction efficiency for l-tyrosine. In addition, the experimental data are correlated using the NRTL model. The comparisons between the correlation and the experimental data reveal a good agreement.     

Solubility,volumetric properties and viscosity of the sustainable systems of liquid poly(ethylene glycol) 200 with imidazolium- and phosphonium-based ionic liquids: Cation and anion effects

In this work, solubility, volumetric and viscosity behavior were studied for the systems containing the environmentally acceptable compounds: liquid poly(ethylene glycol) (PEG200) and three ionic liquids: 1-butyl-3-methylimidazolium dicyanamide ([C₄mim][dca]), trihexyltetradecyl phosphonium dicyanamide ([P_6,6,6,14][dca]) and 1-hexyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}amide ([C₆mim][NTf₂]). The studies were performed in a temperature range (288.15 to 328.15) K and at a pressure of 0.1 MPa. For the only system that evidenced limited miscibility, namely (PEG200 + [P_6,6,6,14][dca]), the temperature-composition phase diagram at 0.1 MPa was determined, mapping the existing one- and two-phase regions. In the homogeneous region of this diagram, densities and viscosities were measured and the excess molar volumes, as well as deviations in viscosity were calculated. For the other two systems, as they are always homogeneous in the temperature ranges of the present work, these measurements and calculations were performed in the full range of compositions. The molecular interactions in the studied systems were scrutinized using the obtained excess molar volumes, deviations of viscosity, as well as Kamlet–Taft parameters of PEG200 and the ionic liquids. In addition, the excess molar Gibbs free energies of activation of viscous flow and the related enthalpies and entropies were calculated and introduced to take into consideration the differences in size of the molecules.     

Thermodynamic studies on protonation constant of adenosine and guanosine at different temperatures and ionic strengths

Stepwise protonation constants of two purine nucleosides (adenosine and guanosine) were determined at different temperatures (293.15 to 308.15) and various ionic strengths (0.101 to 3.503 mol · kg⁻¹ NaClO₄) using a combination of potentiometric and spectrophotometric method. The thermodynamic parameters (i.e. enthalpy change, ΔH, and entropy change, ΔS) of the protonations were calculated at different temperatures using van’t Hoff and virial equations. The dependence of the protonation constant on ionic strength is modeled by a Debye–Hückel type equation and discussed. Finally, the protonation constants of the nucleosides and the enthalpy change of protonations were determined at zero ionic strength.