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The paper presents structural, surface, thermodynamic and kinetic characteristics of titanium dioxide samples obtained by means of alkaline hydrolysis of TiCl4 by LiOH solutions and further heat treatment. TiO2 samples have the anatase structure with crystallite size of 7–10 nm. An increase in the heat treatment temperature from 150 °C to 470 °C leads to a decrease in the specific surface area from 404 to 80 m2/g and the total pore volume from 0.340 to 0.152 cm3/g. The influence of electrolyte composition and surface properties of TiO2 on its behavior in cells with lithium anode investigated by means of galvanostatic cycling and impedance spectroscopy is discussed.

Lithium-manganese-rich–lithiated nickel-manganese-cobalt oxides are advantageous for using in lithium-ion batteries due to low toxicity and high specific capacity but suffer from low high-rate capability. In this paper, characterization and electrochemical testing of 0.5Li2MnO3·0.5LiNi0.5Mn0.3Co0.2O2 (Li1.2Ni0.2Mn0.52Co0.08O2) obtained by means of a citric acid–aided route is described. It demonstrates excellent electrochemical performance possessing specific capacity equal to the theoretical value (280 mAh g−1), being able to be discharged with currents of 2240 mA g−1 (8 C), having high coulombic efficiency (~ 99%) even after high-rate tests, and manifesting low capacity fade after high current loads and upon further cycling by 0.1 C currents (0.144 mAh g−1 per cycle).

Commercial thermoplastic plasticized polymer films based on polyvinyl acetate of different chemical compositions and composite metal-viscoelastic polymer film-metal three-layer materials were studied by dynamic mechanical analysis. The dependences of the mechanical loss coefficient and elastic modulus of polymer films on temperature and strain frequency at dynamic extension were determined experimentally. The temperature intervals of efficient damping were determined. In these intervals, the mechanical loss coefficient of each polymer film exceeds 0.5 for the frequency range 1–10 000 Hz. The dissipative properties of polymer films and composite materials based on them were compared. The mechanical loss coefficients of the films materials are higher than those of the composite materials, but the composite materials have higher mechanical loss moduli. Their absolute values at the maximum-damping temperature reach ∼1011 Pa and more, which allows using them as effective vibration-damping coatings.

1 M solutions of NaClO4 mixed with ethylene carbonate, dimethyl carbonate, and fluoroethylene carbonate were studied as electrolytes for a double-layer supercapacitor with electrodes made of Norit DLC Supra 30 activated carbon. It was shown that the specific capacity of activated carbon depends on the electrolyte composition, range of cycling voltages, and current density. The maximum specific capacitance of 40 F g–1 was obtained in 1 M NaClO4 mixed with ethylene carbonate: dimethyl carbonate: fluoroethylene carbonate (4: 5: 1) at a current density of 36 mA g–1 in the range 10–2300 mV. The minimum specific capacitance was obtained under the same cycling conditions in the electrolyte with 1 M NaClO4 + ethylene carbonate: dimethyl carbonate (1: 1). The variation of the specific capacitance with the electrolyte composition and range of cycling voltages is accounted for by the existence of a pseudocapacitance caused by the occurrence of side processes on the surface of activated carbon. The impedance spectroscopy was used to find that the introduction of fluoroethylene carbonate into the electrolyte positively affects the charge-transfer resistance and favors an increase in the specific capacitance of activated carbon.

Citrate precursors of copper, nickel and cobalt oxides, namely Cu(C6H7O7)2·5H2O, Ni(C6H7O7)2·2.5H2O and CoC6H6O7·6H2O, have been synthesized from solutions with metal to citric acid ratio of 1:2, their thermal decomposition has been studied, and decomposition products have been analyzed. It has been found that the Cu salt loses water and then forms acidic aconitate and acidic itaconate, which then transforms to normal itaconate and further to CuO. The Ni salt dehydrates and decomposes directly to normal itaconates and then to NiO mixed with Ni metal. The Co salt dehydrates and then transforms to normal aconitate, normal itaconate and to Co3O4 containing CoO. While the oxides in question form crystallites of 15–25 nm size with pores of around 3–4 nm in radii, their morphology differs significantly. CuO particles are nanosized. Unlike them, NiO and Co3O4 develop aggregates of approx. 300–500 nm size. Similarities and differences in decomposition processes and morphology of the target oxides are analyzed and discussed, and possible improvements of the citric acid-aided route are suggested. It is shown, in particular, that the formation of metallic Ni and CoO is predetermined by thermodynamics of redox processes involving oxygen and carbon monoxide obtained by the decomposition of the organic part of precursors.

Еlectrochemical performance of Co 3 O 4 in lithium-ion batteries is briefly reviewed. Co 3 O 4 samples are synthesized via microwave-assisted solid state and citric acid aided methods. It is shown that the latter method leads to disperse nanosized materials having discharge capacity close to the theoretical value. Several electrolytes are probed so as to minimize capacity losses upon cycling, and the one containing lithium bis(trifluoromethane)sulfonimide in a mixture of fluoroethylene carbonate and dimethyl carbonate is selected. High-rate tests reveal that capacity retention of the samples obtained is well comparable with the best existing data, and at the current load of 5340 mA g −1 (6C) all materials studied retain more than 50% of initial capacity.

The electrochemical behavior of electric double layer capacitors (EDLCs) with tetramethylammonium bis(oxalato)borate electrolyte and electrodes based on various activated carbons (ACs) was studied. Tetraalkylammonium bis(oxalate)borate salts were synthesized by means of microwave (MW) irradiation. The specific conductivities of salt solutions were determined. It was shown that the efficiency of electric double layer capacitors increases with an increase in specific surface area and a decrease in the purity of carbon materials.

Synthesis of Co3O4 powders by the microwave method from citrate precursors is described. The structural, surface, and thermogravimetric characteristics of the resulting powders were studied depending on the cobalt ions and citric acid ratio. The specific capacity of the samples was determined to be from 665 to 831 mA h g–1 after 100 cycles at a current density of 0.5C.

Our recent Raman studies of cation and anion solvation and ion pairing in solutions of lithium salts in dimethyl sulfoxide, propylene carbonate, and dimethyl carbonate are briefly overviewed. Special attention is paid to differences in our and existing data and concepts. As follows from our results, cation solvation numbers in solutions are low (~2) and disagree with previous measurements. This discrepancy is shown to arise from correct accounting for dimerization, hydrogen bonding, and conformation equilibria in the solvents disregarded in early studies. Another disputable question touches upon the absence of free ions in solutions of lithium salts in carbonate solvents and the statement that the charge transfer in carbonate solutions is caused by SSIPs. Direct proofs of the nature of charge carriers in the solvents studied have been obtained by means of analyses of vibrational dynamics. It has been found that collision times for free anions are short and evidence weak interactions between anions and solvent molecules. In SSIPs, collision times are an order of magnitude longer thus signifying strong interactions between anions and cations. In CIPs, collision times become shorter than in SSIPs reflecting the transformation of the structure of concentrated solutions to that of molten salts.

Phase diagrams of lithium salt systems in dimethyl sulfoxide, propylene carbonate and dimethyl carbonate have been obtained and conductivity measurements have been performed in the concentration range up to 0.25 mole fraction of a salt. The shape of the phase diagrams has been analyzed thermodynamically and the following order of anions for decreasing association of salts with DMSO at cLiX = 0.2 has been suggested, ClO4− > CF3SO3− > BF4− > NO3−. The eutectic-type phase diagrams of the LiClO4-PC and LiClO4-DMC systems correspond to ideal, non-interacting solutions. The conductivity isotherms for the DMSO solutions at cLiX = 0.2 are arranged in the order of increasing conductivity as CF3SO3− c LiClO 4 = 0.5–1 mole fraction of the salt, the order of solvents for increasing conductivity is DMC

Raman study of cation and anion solvation in dimethyl sulfoxide, propylene carbonate and dimethyl carbonate solutions of six lithium salts has been performed in the concentration range from 0.05 to 0.25 molar fraction of a salt. The dependences of the amount of the solvent particles involved in dimerization, hydrogen bonding, and solvation have been determined, and the mean solvation numbers have been found. It is concluded that in all solutions studied, notwithstanding the differences in the physical properties of the solvent and in the structure of the anion, both the lithium cation and the anion solvation equilibria are quantitatively similar. In all cases, solvation numbers of cations are close to two and do not vary with the growth of concentration. In particular, in molten LiX·4S solvates, LiS 4 + entities expected from the phase diagrams do not exist. It has been found that for the solvent molecules in dimers and in solvation spheres, non-coincidences between vibrational frequencies of isotropic and anisotropic lines, Δ ν NCE = ν aniso − ν iso are of opposite signs signifying that the mutual orientation of molecules is different. In all systems studied, solvation numbers of anions decrease if the salt content is growing and are close to four in concentrated solutions. These striking similarities in the structure and concentration of solvated entities clearly signify that solvation phenomena have no decisive importance in determining the properties of salt systems.

Ionic equilibria in the LiBF4-dimethyl sulfoxide (DMSO) system were studied by Raman spectroscopy at 50°C at salt concentrations of 0.05–0.25 mole fractions. The spectral signals of hydrogen bonds between the DMSO molecules and the fluoroborate ions were found. The concentrations of the monomer and dimer DMSO molecules and DMSO molecules in the solvation sphere of the lithium cation; free solvent molecules and those in the solvation sphere of the fluoroborate ion; free anions, ion pairs separated by the solvent, and contact ion pairs were determined.

The phase diagram and electrical conductivity isotherms for the lithium tetrafluoroborate (LiBF4)–dimethylsulfoxide (DMSO) system and Raman spectra of DMSO and the LiBF4–DMSO solution were studied. Spectroscopic signatures of a H-bond between DMSO and BF4 − ions were found. The bonds of Li+ ions to the solvent were stronger than the bonds in DMSO dimers because formation of the solvate destroyed dimeric DMSO molecules. The τω values for DMSO molecules in the Li+-ion solvate shell of the LiBF4–DMSO system were similar to those for associated solvent molecules.

The Raman spectra of the mixtures containing the low-temperature ionic liquid ethylmethylimidazolinium bis(trifluoromethanesulfonyl)imide (EMIIm), the salt component lithium bis(trifluoromethylesulfonyl)-imide (LiIm), and the aprotic solvent ethylene carbonate (EC) are studied. It is found that the addition of the lithium salt to the ionic liquid results in the formation of ion pairs or more complex cation-anion aggregates. Dilution of these systems with ethylene carbonate leads to the solvation of lithium ions.

Polybasic hydroxy and amino carboxylic acid routes offer great advantages for the synthesis of powdered oxide nanomaterials of high surface area and porosity. A detailed analysis of the state-of-the-art in the field is performed, and some unresolved problems are discussed. Precursors of zinc oxide with the Zn2+:citric acid:ethylene glycol ratio of 1:1:0, 1:2:0, 1:4:0, 1:2:1, 1:2:2, 1:2:4 and 1:2:10 are studied. Their thermal decomposition is analyzed using DTA, IR, XRD, SEM, TEM methods, and porosity measurements in order to determine the component ratio and heating temperature enabling one to obtain the target oxide of the smallest particle size, the highest surface area, and the maximal amount of micropores. It is found that such a goal can be reached with the precursor of the 1:2:0 component ratio thermally treated at 400 °C.

The contours of the bands corresponding to totally symmetrical vibration ν1(A1) and vibration overtone ν2(E) of the perchlorate ion in molten lithium perchlorate are studied. Vibrational dephasing is found to be the main factor of the broadening of isotropic spectral bands. The dephasing of vibrations in an LiClO4 melt is shown to obey a Gaussian-Markovian mechanism.

An analysis of the Raman spectra of the solutions of lithium salts in dimethyl sulfoxide, propylene carbonate, and dimethyl carbonate in a concentration range from diluted solutions to the mixtures of molten solvates with salts has been performed in terms of the dynamics, specifically, the dephasing (тv) and modulation (тw) times of all molecular entities present in solutions are determined and analyzed. It has been found that, in the picosecond time domain, the dephasing and modulation in solvent molecules hydrogen-bonded with an anion and/or solvating a cation are slower than in free solvent molecules. In solvent separated ion pairs, both тv and тw are much longer than in solvated anions, thus indicating the strong interactions between anions and their surrounding. In contact ion pairs, тv are great, whereas тw appear close to those for free anions. This reflects that the structure of the liquid tends to the structure of molten salts.

This work reports phase diagrams, conductivity isotherms, and data regarding the structure and dynamics of systems formed by lithium perchlorate and nitrate as solutes and sulfones as solvents. The LiClO4 + (CH3)2SO2 system behaves like typical electrolytic systems containing a lithium salt and a solvent and forms a 1:1 solvate; its conductivity isotherm demonstrates a maximum. Unlike typical systems, the phase diagrams of the LiNO3 + (CH3)2SO2 and LiNO3 + (C2H5)2SO2 systems appear to be simple eutectic. The dependences of specific conductivity on the concentration of LiNO3 are also uncommon showing no maximum characteristic to electrolyte solutions. Raman studies and analysis of dynamics performed using Raman data signify that, in the LiClO4 + (CH3)2SO2 system, solvated cations and contact ion pairs exist. In the LiNO3 + (CH3)2SO2 system, contact ion pairs are present as well, but signatures of cation solvation cannot be found.

The possibility of preparing lanthanum(III) hydroxide and a 1:1 mixture of lanthanum(III) hydroxide with hydrated titania by precipitation from aqueous solutions was explored. The maximal sorption capacities of the mixture with respect to phosphate ions in acid and alkaline media were determined. The mechanism by which phosphates are removed was elucidated by IR spectroscopy.

The oxidation of aqueous solutions of manganese (II) chloride by hydrogen peroxide leads to the mixture of hausmannite (Mn3O4) with manganite (MnOOH). Being air dried, this mixture undergoes slow oxidation at room temperature during which the content of manganite is rising, and an equilibrium molar ratio Mn3O4:MnOOH reaches 1:3 in approx. 1 year of storage. In terms of reversible first order reactions, rate constants for the forward and reverse reactions are 2.62 × 10−1 and 8.75 × 10−2 month−1, respectively. In the course of oxidation, additional IR adsorption bands emerge in the region of vibrations of physisorbed water molecules at 3160 and 3300 cm−1. These bands are absent in IR spectra of equilibrium mixtures and disappear after treatment of samples with Sr2+ ions as a result of ion exchange. This finding enables one to suggest that adsorbed water forms cation exchangeable surface groups Mn (OH)2 whose transformation into MnOOH is a step determining the oxidation rate. On the other hand, these data may be considered as the first spectroscopic evidence of sorption of spherical cations onto the surface of hydrous oxides.

Complex formation of zinc(II) with citric acid in acidic medium was studied by pH-potentiometric titration at various metal to acid ratios. The speciation diagrams of the complexes in relation to pH were plotted, and the stability constants of the complexes were determined. Precursors of the synthesis of metal oxide materials were prepared at two reactant ratios. A scheme of the precursor thermal decomposition based on data of derivatography and IR spectroscopy was suggested, and the compositions of compounds formed during decomposition were determined.

The results of my latest research into molten halides of alkali and alkaline-earth metals by a method of Raman spectroscopy are reviewed. A dynamic criterion for the formation of complexes in melts is considered. The results that testify to the existence of instantaneous and short-lived autocomplexes in these liquids are analyzed in the light of an autocomplex model for the structure of melts.

Raman scattering spectra of dimethyl sulfoxide (DMSO) are studied in the area of the line corresponding to symmetric CSC stretching vibrations of the molecule. It is established that this line is composed of a low-frequency component that corresponds to the vibrations of monomeric molecules and a high-frequency component that corresponds to the vibrations of DMSO dimers. Values of self-association equilibrium constants K a varying in range from 0.20 (23°C) to 0.081 (100°C) are obtained. Since the intensities of the respective components of the line contour are proportional to the compound’s concentrations, the enthalpy of DMSO self-association (ΔH = −11.7 ± 0.9 kJ/mol) is determined from the temperature dependences.

Possible relations between several characteristic times, viz. the vibrational dephasing time τ V , the vibrational frequency modulation time τ ω , the time between collisions in a liquid τ BC , the collision duration time τ d , and the half-period of vibration T /2 are considered. It is found that for instantaneous collision complexes the following relations hold: τ ω ≈ T /2 or τ V ≈ T /2. For short-lived complexes τ ω ≤ τ d or τ V ≤ τ d , and 0.5≤ τ ω / T ≤2 or 0.5≤ τ V / T ≤2, whereas for long-lived species τ ω ≤ τ d or τ V ≤ τ d , and τ ω ,/ T ≥2 or τ V / T ≥2.

Raman spectroscopy has been used to investigate picosecond vibrational dynamics of the molecular glass-former phenyl salicylate (salol). The study has concentrated on the elucidation and comparison of molecular dynamics of salol subjected to different local environments, namely in bulk, in a dilute CCl4 solution, and under spatial confinement in nanoporous sol–gel glasses. Contrary to most of the previous picosecond dynamics studies performed by means of Raman line profile analysis, we have employed in this paper a novel approach that enables the extraction of valuable short-time dynamics information through spectra fitting in the frequency domain. As a result, strongly overlapping vibrational lines can be put in focus. The analysis has shown a systematic dependence of vibrational relaxation on the local environment around a salol molecule. The magnitude of the vibrational relaxation time τV decreases in the sequence dilute solution→bulk liquid→confined liquid, indicating the modification of interactions ...

Polarised and depolarised low-frequency Raman spectra of liquid formamide have been analysed. The employed fitting procedure shows convincingly that the Boson peak contribution to the overall low-frequency Raman pattern is present even in this ordinary, low-viscous liquid.

A computational approach was elaborated to explicitly account for the Rayleigh line wing, the Boson peak and vibrational contributions to the low-frequency Raman spectra of amorphous solids and viscous liquids. It was shown that the low-frequency Raman spectra of glycerol and polystyrene consist of the Rayleigh contribution of Lorentzian form and the Boson peak which profile follows the predictions of the theory by Martin and Brenig in the version by Malinovsky and Sokolov. In the case of triacetin, the Boson peaks decay faster in their high-frequency side than the above theory predicts. Their form can be successfully modeled with a newly introduced empirical function intermediate between the Martin–Brenig and Malinovsky–Sokolov predictions.

Distinguishing features of spectroscopy of interparticle interactions in ionic liquids are pointed out. Studies of interactions and picosecond dynamics in molten salts using this approach are reviewed. Similarities and differences between molecular and ionic liquids which manifest themselves in spectroscopic experiments are compared and discussed.

Dimethyl sulfoxide (DMSO) has been known for almost 150 years, but its properties as a solvent and reaction medium are far from being understood. In particular, association equilibriums in liquid DMSO have been characterized in just four papers, and the enthalpy of its self-association is unknown. The aims of this paper are to study self-association equilibriums in neat liquid DMSO at various temperatures by means of Raman spectroscopy, to find the enthalpy of self-association, and to solve the problem of hydrogen bonding in this liquid. Time correlation functions of vibrational dephasing and reorientation of coexisting monomers and dimers studied by the C-S-C and C-H symmetric vibrations indicate that external perturbations and vibrational and reorientational dynamics of these particles occur on different time scales. No signatures of H-bonding in DMSO are found. The association constants vary from 0.20 L mol(-1) (23 °C) to 0.081 L mol(-1) (100 °C). Their temperature dependence gives the enthalpy of association of DMSO as -11.7 ± 0.9 kJ mol(-1).

Decreasing the size of oxide particles to nanoscale enables one to ensure maximal reaction rates and depths in the solid due to the enhancement of the specific surface area and the increase of the diffusion rate caused by shortening diffusion paths. For that reason, one may suggest that in the case of adsorption onto nanoparticles, the complete conversion of sorbents to stoichiometric compounds would become possible. Adsorption of phosphate ions onto nanosized hematite supported on silica gel surface has been studied. Modification of silica gel surface by hematite in the quantity of 0.62 and 1.25 mass% has been carried out by means of a citric acid aided method. The morphology of the samples obtained has been characterized using DTA, XRD, SEM, and low temperature desorption of nitrogen. It has been found in batch experiments that unlike natural and synthetic hematites, for which the limiting adsorption values do not exceed 14 mg/g, silica gel supported nanosized hematite adsorbs 400–2000 mg of the phosphate ions per gram, thus forming near-stoichiometric iron phosphates on the surface of the support. The degree of conversion of hematite to iron phosphates is greater in acidic media and at a lower surface coverage, when hematite crystallites are small and better accessible by adsorbate.

The anomalous frequency non-coincidence effect in strongly interacting liquids (ω iso > ω IR ) was interpreted in terms of non-resonant splitting caused by short-range interparticle repulsion. The shift of the in-phase component of the split lines was found to depend mainly on ds i /dQ j , the derivative of the vibrational displacement of the ith atom with respect to the normal coordinate of jth vitration. For molten potassium thiocyanate, the numerical estimations agree well with the experimental data

The most obvious consequence of the concept of aromaticity is the common confidence that in aromatic compounds, bond lengths do not alternate and are between typical to the single and double ones. However, in 1994, performing crystal structure investigations of substituted pyridines and their salts, Krygowski and co-workers have discovered a very surprising angular group induced bond alteration (AGIBA) effect: It appears that some angular substituents, like methoxy or nitrozo groups, can induce bond alternation in aromatic rings. Crystal studies do not allow one to operate with liquids that are more common in organic chemistry. This paper presents the first possible evidence of spectroscopic manifestations of the AGIBA effect. Raman spectra of the liquid toluene are analyzed. It is found that instead of being single, the line corresponding to the ring breathing vibrations is clearly split by 1.0–1.4 cm−1, thus indicating the presence of two (cis- and trans-) AGIBA isomers. The energy difference between these isomers estimated in temperature dependent Raman studies is found equal to 6.68 kJ mol−1. The low-wavenumber line therefore corresponds to the cis-AGIBA isomer and the high-wavenumber line to the trans-AGIBA isomer stabilized by the AGIBA effect. Copyright © 2007 John Wiley & Sons, Ltd.

A short review of results obtained in latest infrared and Raman studies, with special reference to in situ measurements and first-principles quantum-mechanical investigations of adsorption and oxidation of alcohol molecules over different (metallic, semiconductor and oxide) surfaces and metal/oxide interfaces is presented, and differences and similarities in the behaviour of methanol and ethanol are discussed.

A comparison of the behaviour of commercial electrochemical manganese dioxide (γ-MnO 2 ) and non-stoichiometric anodic Mn x O y (OH) z was made. Anodic oxide proves to be composed mainly by MnO 2 (ramsdellite) and MnOOH (manganite), and contains more water and OH − than γ-MnO 2 . Hydroxide ions were shown to determine the ionic conductivity of Mn x O y (OH) z which, in turn, strongly affects the rate of electroreduction.

Low-frequency vibrational spectra yield the information about molecular dynamics in condensed matter [1]. In this paper the low-frequency Raman (LFR) and farinfrared (FIR) spectra of water/glycerol mixtures at different concentrations are presented. The spectra of glycerol and water in this region are rather complicated due to the presence of hydrogen bonding [2]. The experimental data are analysed in terms of different models. In particular the peak position calculated using the formulae introduced in [3], where the relation of frequency maximum with the isothermal compressibility has been established.

The rates of perchlorate decomposition in various molten salt solvents have been studied. Activation energies of both catalytic and noncatalytic processes are close and the differences between the rates of these two processes are due to the variations of pre-exponential factors.

Amorphous TiO2 obtained by adding TiCl4 to an alkaline medium crystallizes slowly and upon 3 years ageing transforms to nanosized anatase containing an admixture of brookite. The hydrothermal treatment of this sample in solutions of lithium hydroxide leads to anatase nanoleaves, and the more concentrated LiOH solution, the greater the nanoleaves and the smaller their specific surface area. The thermal treatment of nanoleaves leads to the bulk rutile, and the greater the specific surface area of anatase nanoleaves, the lower the anatase–rutile transition temperature. This is in line with conclusions based on the thermodynamic stability of nanosized anatase over the bulk rutile.

The frequencies of radical displacement can be obtained from matrix ELDOR spectra. ELDOR of radicals with anisotropie g-factor is determined by radical rotation around the angle given by pumping and observing frequency difference. The two ELDOR mechanisms are determined for nitroxide radicals in plastic solids and sulfur anion-radical in oleum.