Home – Home – Jornals – Chemistry for Sustainable Development 2002 number 6

The basic principles of operation of Li-ion batteries (Li-ion) are considered; equations for the electrode potential and charge/discharge kinetics are presented. The most widespread materials for the negative and positive electrodes are described, as well as the composition of electrolytes, their properties and behaviour in Li-ion. The world market and outlooks of the Russian market are analyzed.

By analogy with thermodynamic notions, implying that the possibility for a reaction to proceed is determined by Gibbs' energy, which is equal to the difference of the energies for the final and initial products, it is proposed to calculate the difference of the sums of mean orbital electro-negativities for the final an initial products. A linear correlation has been established between Gibbs' energies of reactions and the mentioned differences, on the basis of vast experimental material for various reaction types. This correlation can be used to estimate the possibility of a reaction between the compounds for which thermodynamic data are unknown, in particular for complicated multi-component compounds.

Physicochemical properties of non-equilibrium solid solutions in metal systems obtained mechanochemically are investigated by means of high-resolution microscopy, X-ray diffraction and differential scanning calorimetry (DSC). It is demonstrated that nano-crystalline non-equilibrium solid solutions possess the excess free energy due to the presence of non-equilibrium non-stoichiometric defects and high density of inter block boundaries. The whole set of these defects creates synergetic effect in chemical activity.

Comparative investigations of phase formation processes and electronic properties of indium and tin oxide materials obtained under different conditions of solid-phase synthesis are presented. Substantial influence of synthesis conditions and temperature of hydrolysis product annealing on phase composition and size of crystallites of the synthesized indium and tin oxide materials is demonstrated. It is stated that the best optimal method to obtain materials with high concentration of free charge carriers is hydrolytic procedure with the use of hydrochloric acid solutions.

Double lithium-aluminium hydroxide [LiAl₂(OH)₆][Cunta] ^. 3H₂O^. containing copper complex with the anion of nitryltriacetic acid (nta) is synthesized by means of anion exchange for the first time. It is shown with the help of X-ray phase analysis that the size of layer packet of the synthesized compound is 11.8 Å. It is established by means of mass spectrometry that the process of water evolution due to dehydroxylation of [LiAl₂(OH)₆]⁺ layers starts simultaneously with the destruction of complex anion [Cunta]

Investigation of phase formation in the system Lu

Processes that occur during the heating of the stoichiometric and defect lithium cobaltite are investigated. This compound is usually considered as one of the most promising cathode materials for secondary lithium batteries. Analysis of thermal stability of chemically deintercalated Li₁

The dependence of the enthalpy of formation of Nd_{1 + x}Ba₂

The heat capacity for tris-dipivaloylmethanate of iron Fe(C₁₁O₂H₁₉)₃ within the temperature range 57

Chemical stability of the microwave ceramics of the system composed of silicon carbide

A fibrous material composed of filamentary crystals of iron carbide Fe₃C or metal iron encapsulated in graphite shells is synthesized. Combined investigation of the structure of the obtained material is performed by means of electron microscopy, powder X-ray diffractometry and Mössbauer spectroscopy. It is discovered that current-voltage characteristics of auto-emission properties of nanoparticles differ from the properties of pure carbon nano-tubes, which is explained by different adsorption characteristics of these materials.

Thin-film materials based on zirconium dioxide and the oxides of iron triad elements are obtained. Physicochemical processes of their formation are investigated. It is stated that the films are dielectrics with large refractive index (2.0

The necessity of broadening and intensification of fundamental research is substantiated for the development of processes which would be the basis of principally new technologies of processing solid fossil fuel to obtain valuable chemical products and materials.

Thermal decomposition of palladium acetylacetonate intercalated into fluorocarbon matrix is investigated by means of mass spectrometry. It is demonstrated that thermal decomposition occurs within a narrower temperature range, at higher rate and comes to its completion at lower temperature (~200 °C) than for the case of individual Pd(AA)₂.

Iron (II) complexes with 1,2,4-triazoles are promising thermochromic materials. New complexes of iron (II) perrhenate and dodecahydro-closo-dodecaborate with 1,2,4-triazole (Htrz) and 4-amino-1,2,4-triazole (NH₂trz) of the composition FeL₃A_n × mH₂O (n = 1, 2; m = 4, 5) are synthesized and investigated. The compounds are studied by means of magneto-chemistry, XPA, electron and IR spectroscopy. Magnetochemical data show that the complexes possess ¹A₁ <=> ⁵T₂ spin transition. The spin transition is accompanied by thermo-chromism (change of colour from pink to white).