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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. Source


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). Source


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. Source


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. Source


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. Source

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