Institute for Sorption and Problems of Endoecology

Kiev, Ukraine

Institute for Sorption and Problems of Endoecology

Kiev, Ukraine
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Potapenko A.V.,8A Vernadsky Ave. | Chernukhin S.I.,8A Vernadsky Ave. | Romanova I.V.,Institute for Sorption and Problems of Endoecology | Kirillov S.A.,8A Vernadsky Ave. | Kirillov S.A.,Institute for Sorption and Problems of Endoecology
Electrochimica Acta | Year: 2014

The citric acid aided synthesis, physico-chemical and electrochemical characterization of the nanosized nickel-doped lithium manganese spinel, LiNi0.5Mn1.5O4 having excellent high-rate properties is described. An optimal electrode material represented by perfectly shaped, well-faceted particles of 100-400 nm size containing crystallites of the 15-22 nm size could be obtained upon the thermal treatment at 700 °C. In spite of a reduced specific capacity (102 mAh·g-1) it is able to retain a half of it upon the discharge current of 4400 mA·g -1 (30 C) and to endure the current load of 5870 mAh·g -1 (40 C) delivering the reversible specific capacity of 25 mAh·g-1. It is suggested that the reduced specific capacity is determined primarily by the aggregation of material's particles, whereas the good high-rate capability is governed not only by the size of crystallites but also by the perfectness of crystals, and imperfections in big, well-shaped crystals (like dislocations, grain boundaries, etc.) less retard the diffusion of lithium ions than particle boundaries in small, randomly oriented, accreted crystals. © 2014 Elsevier Ltd.


Kirillov S.A.,8A Vernadsky Avenue | Kirillov S.A.,Institute for Sorption and Problems of Endoecology | Gorobets M.I.,Institute for Sorption and Problems of Endoecology | Gafurov M.M.,Kh I Amirkhanov Institute Of Physics | And 2 more authors.
Journal of Physical Chemistry B | Year: 2013

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. © 2013 American Chemical Society.


Potapenkoa A.V.,8A Vernadsky Ave. | Kirillov S.A.,8A Vernadsky Ave. | Kirillov S.A.,Institute for Sorption and Problems of Endoecology
Journal of Energy Chemistry | Year: 2014

In order to successively compete with supercapacitors, an ability of fast discharge is a must for lithium-ion batteries. From this point of view, stoichiometric and substituted lithium manganese spinels as cathode materials are one of the most prospective candidates, especially in their nanosized form. In this article, an overview of the most recent data regarding physico-chemical and electrochemical properties of lithium manganese spinels, especially, LiMn2O4 and LiNi0.5Mn1.5O4, synthesized by means of various methods is presented, with special emphasis of their use in high-rate electrochemical applications. In particular, specific capacities and rate capabilities of spinel materials are analyzed. It is suggested that reduced specific capacity is determined primarily by the aggregation of material particles, whereas good high-rate capability is governed not only by the size of crystallites but also by the perfectness of crystals. The most technologically advantageous solutions are described, existing gas in the knowledge of spinel materials are outlined, and the ways of their filling are suggested, in a hope to be helpful in keeping lithium batteries afloat in the struggle for a worthy place among electrochemical energy systems of the 21st century. Copyright © 2014, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. All rights reserved.


Fesich I.V.,Taras Shevchenko National University | Trachevsky V.V.,NASU G.V. Kurdyumov Institute For Metal Physics | Dziazko A.G.,Taras Shevchenko National University | Nedilko S.A.,Taras Shevchenko National University | Melnik A.K.,Institute for Sorption and Problems of Endoecology
Journal of Applied Spectroscopy | Year: 2014

Lanthanum cobaltates modified by alkaline-earth-metal (0.10 mol%) and lithium (0.05 mol%) ions were synthesized. The samples had an orthorhombic distorted perovskite-like structure according to x-ray diffraction phase analysis. Addition of Li+ and M2+ (M = Ca, Sr, Ba) to the LaCoO3 matrix was shown to increase the unit-cell parameters, the optical band width (Eg), and the average Co oxidation state (Con+). Pure and doped LaCoO3 were characterized by the presence of paramagnetic centers as isolated structural and surface Co2+ ions and adsorption complexes [Co3 + ⋯ O2 −]· on the surface of the oxide matrix at a concentration that increased in the order Ba > Sr > Ca. The cobaltates were found to possess Mott hopping conduction in the temperature range 77–298 K. © 2014, Springer Science+Business Media New York.


Potapenko A.V.,8A Vernadsky Ave. | Chernukhin S.I.,8A Vernadsky Ave. | Kirillov S.A.,8A Vernadsky Ave. | Kirillov S.A.,Institute for Sorption and Problems of Endoecology
Materials for Renewable and Sustainable Energy | Year: 2015

Lithium manganese spinels tend to aggregate upon annealing and do not allow for attaining high discharge rates when used as cathodes in lithium-ion batteries. To obtain spinel samples of lower aggregation and better high-rate properties, precursors synthesized by means of a citric acid-aided route are suggested to be pyrolyzed in an inert atmosphere, instead of pyrolysis in air. The synthesis of nanosized Li[Li0.033Mn1.967]O4 is described, and its characteristics including X-ray diffraction, scanning electron microscopy, and porosity, as well as electrochemical test results are presented. The particle size of the materials obtained is smaller, the degree of aggregation is lower, and high-rate properties are better than for analogues pyrolyzed in air. In particular, sample Li||Li[Li0.033Mn1.967]O4 cells deliver ~60 mAh g-1 at the current loads of 4,000 mA g-1 (30 C). After a sequence of 62 charge/discharge cycles with the currents growing from 0.1 to 100 C the specific capacity retains its initial value. © 2014 The Author(s).


Kirillov S.A.,8A Vernadsky Ave. | Kirillov S.A.,Institute for Sorption and Problems of Endoecology | Lisnycha T.V.,Institute for Sorption and Problems of Endoecology | Chernukhin S.I.,8A Vernadsky Ave.
Journal of Power Sources | Year: 2011

Two types of titanium dioxide samples precipitated from aqueous solutions of titanium tetrachloride are investigated. Crystalline materials are obtained by means of neutralization of TiCl4 with the solution of an alkali metal hydroxide. The change of the order of mixing leads to amorphous materials. The evolution of the samples upon the thermal treatment is characterized using XRD, SEM, TEM and porosity studies. The application of crystalline TiO 2 as an electrode material in lithium-ion 2016 sample cells enable one to yield specific currents up to 3350 mA g-1. On the other hand, the thermal treatment of initially amorphous materials does not lead to complete crystallization, and the presence of amorphous TiO2 is well seen as the so-called capacity behavior of cyclic voltammetry curves. © 2010 Elsevier B.V.


Tretyakov D.O.,8A Vernadsky Ave. | Prisiazhnyi V.D.,8A Vernadsky Ave. | Gafurov M.M.,Kh A Amirkhanov Institute Of Physics | Rabadanov K.S.,Kh A Amirkhanov Institute Of Physics | And 2 more authors.
Journal of Chemical and Engineering Data | Year: 2010

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 + (C2H 5)2SO2 systems appear to be simple eutectic. The dependences of specific conductivity on the concentration of LiNO 3 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)2SO 2 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. © 2010 American Chemical Society.


Sobiesiak M.,Maria Curie Sklodowska University | Gawdzik B.,Maria Curie Sklodowska University | Puziy A.M.,Institute for Sorption and Problems of Endoecology | Poddubnaya O.I.,Institute for Sorption and Problems of Endoecology
Xinxing Tan Cailiao/New Carbon Materials | Year: 2011

Thermogravimetry and differential scanning calorimetry were used for characterization of the thermal properties of new 4, 4'-bismaleimidodiphenylmethane (BM) and divinylbenzene (DVB) porous copolymers and their carbonization products. Bead-shaped porous copolymers BM-DVB with the following monomer ratios 1:4, 1:1, 4:1 were synthesized using suspension copolymerization under the same conditions. Differences in the monomer ratio caused a different degree of cross-linking of the starting polymers. Before carbonization, the BM-DVB copolymers were pretreated using two methods. In one method, the starting material was stabilized in hot air (product was labeled PO-C800). In the other method, the copolymer was soaked in H3PO4 (product was named P800). Then, materials obtained by both methods were carbonized at 800°C in an argon atmosphere. To characterize the heat resistance of the BM-DVB copolymers and their carbonized derivatives, their thermostabilities were evaluated. The data suggest the existence of a relationship between the composition and thermal stability of the copolymers and their carbonized derivatives. The most thermally resistant copolymer was that obtained with a 4:1 molar ratio of BM to DVB. Its thermal stability is caused by the high concentration of nitrogen atoms in the polymeric structure. 1:4 BM-DVB copolymer with a high degree of cross-linking was the least thermally stable, which might be caused by its microporous nature and small fraction of nitrogen. The derived carbons have very similar thermal properties, and an insignificant influence of the nature of the polymer precursor was observed. More important factors affecting thermal stability were the porosity and surface chemistry, which were created in the thermal pretreatment processes.


Sobiesiak M.,Maria Curie Sklodowska University | Gawdzik B.,Maria Curie Sklodowska University | Puziy A.M.,Institute for Sorption and Problems of Endoecology | Poddubnaya O.I.,Institute for Sorption and Problems of Endoecology
Applied Surface Science | Year: 2010

The relations between chemical structures of BM-DVB copolymers obtained with various monomer molar ratios and their carbonization products were studied. Three porous copolymers 1:4, 1:1, and 4:1 of BM to DVB were the starting materials for preparation of active carbons. Two activation agents were employed: air and phosphoric acid. The carbonization process was performed in the same way in these two cases. To characterize the obtained materials FTIR spectroscopy, thermal and elemental analyses were applied. Porous structure parameters were obtained by means of nitrogen sorption. The results proved that differences in the molar ratio of monomers used in the syntheses of polymeric precursor play a key role for structure and properties of copolymers but have rather small influence on properties of the obtained carbons. Preliminary treatment is more effective during the activation process. The carbons obtained by activation with phosphoric acid are microporous and have well developed porous structures. The air activated carbons are mesoporous with specific surface areas similar to those of polymeric precursors. © 2010 Elsevier B.V. All rights reserved.


Lapko V.F.,Institute for Sorption and Problems of Endoecology | Svarkovska I.P.,Institute for Sorption and Problems of Endoecology | Kanibolotskyi V.A.,Institute for Sorption and Problems of Endoecology | Gerasymyuk I.P.,Institute for Sorption and Problems of Endoecology
Nanosistemi, Nanomateriali, Nanotehnologii | Year: 2015

The process of palladium nanodispersion-phases' formation on a surface of silica bearer with siliconhydride (=Si-H) groups, hydridpolysiloxane, is investigated by the method of reductive sorption. Reductive-sorption processes for obtaining of metal nanoclusters are carried out with using of H2PdCl4 aqueous solutions, which have hydroxocomplexes of palladium. As shown, the nanoclusters' formation passes owing to interaction of siliconhydride surface groups of bearer with hydrated ions of metal. The morphology of bearer surface and supported Pd nanoclusters are studied by the method of scanning electron microscopy (SEM). © 2015.

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