No abstract

The regularities of the formation of nanostructures during the evaporation of graphite by the electric ARC – method are studied. Described physicochemical processes in the synthesis reactor . At plasma temperatures taking into account the behavior of particles in electromagnetic fields with extreme temperature and pressure grants. A sequence of organization of matter in the process of forming a structure according to nano-dimensional characteristics is proposed. The self-organization of systems during electric arc evaporation of graphite or graphite-containing electrodes has been studied. The mechanisms of formation of soluble (fullerenes and fullerene-like structures) and insoluble (nanocomposites, CNTs, graphenes) carbon nanostructures are considered. The processes occurring in the electric arc synthesis reactor are analyzed: the process of distribution of charged particles in an electric arc at different times; processes taking place at the anode; the mechanism of carbon vapor formation during graphite evaporation; processes in the gas phase and on the walls of the reactor under the conditions of an electric arc discharge; model of the reactor space zones; formation of carbon nanostructures in the gas phase and on the inner surface of the reactor. use of doped electrodes and metal inserts (sleeves) as catalysts for the synthesis of carbon nanostructures. The sequence of processes in the formation of spherical carbon molecules is studied, and the processes and structural transformations are considered. In the research work, the products (fullerenes and fullerene-like structures, nanocomposites, VNT, graphenes) of electric arc synthesis are presented, and modern methods of analysis are used for their fixation and identification.

Even partial replacement of graphite in the anode of lithium-ion batteries with silicon can significantly increase their specific energy. But the issue is the insufficient life cycle of such batteries due to the accelerated degradation of the liquid organic electrolyte with traditional lithium hexafluorophosphate, especially at elevated temperatures. The subject of discussions and further research are the processes involving a natural oxide layer on the surface of silicon in the manufacture and electrochemical litiation–delitiation of Si-containing electrodes. Among the most promising areas for solving the issues of practical application of silicon are new additives to the electrolyte and polymeric binders for electrode masses. This paper demonstrates the capability of trimethylsilylisocyanate (with aminosilane and isocyanate functional groups) as an additive to a liquid organic electrolyte (LiPF6 / fluoroethylene carbonate + ethyl methyl carbonate + vinylene carbonate + ethylene sulfite) to scavenge the reactive HF and PF5 species that alleviates the thermal decomposition of fluoroethylene carbonate at elevated temperatures. This makes it possible to increase the electrochemical parameters of half-cells with a hybrid graphite–nanosilicon working electrode when using water-based binders – carboxymethylcellulose and styrene-butadiene rubber. The addition of trimethylsilylisocyanate in the electrolyte significantly improves the reversible capacity of hybrid electrodes and reduces the accumulated irreversible capacity during prolonged cycling at normal temperature and after exposure at 50 °C, therefore to be effective for use in high-energy lithium-ion batteries.

The solution to the problem of negative impact on the ecology of fossil fuel consumption is the use of electrochemical energy sources. The special attractiveness has shown of lithium power sources is highlighted and the need to develop new cheap electrode materials and electrolytes with unique properties. The peculiarities of the behavior of lithium and the formation of a layer of reaction products on its surface upon contact with a liquid organic electrolyte have considered. The analysis of the main problems and ways of their solution at use of conversion electrodes of the II type for lithium-ion batteries has carried out. Emphasis is placed on the need to use in the development of new electrode materials of such parameters as capacity loading and accumulated irreversible capacity of the electrodes. The triad “electrode – solid electrolyte interphase – electrolyte” is considered as a basis of a systematic approach to the creation of new generations of lithium power sources. The optimal scenarios have proposed for the formation of an effective solid electrolyte interphase on the surface of the electrodes. The advantages of electrolytes based on fluoroethylene carbonate with synergistic acting additives of vinylene carbonate and ethylene sulfite are described. A new strategy for the use of “secondary” silicon nanomaterials to prevent direct contact of its surface with the electrolyte has considered. It has shown that the solid electrolyte interphase is a dynamic system that self-organizes from the unstable state into a stable one. The electrochemical behavior of electrodes with silicon nanocomposites with high capacity loading and low accumulated irreversible capacity has described.