Prykhozha Y. Dichacogenide Transient Metal Films for Anodes of Sodium- and Lithium-Ion Batteries

The dissertation is devoted to the study of dichalcogenide transition metal films for anodes of sodium- and lithium-ion batteries. Methods of density functional theory and pseudopotential from the first principles have been used. Energy storage is a critical component in the development of sustainable energy resources, information technology, electric vehicles, and consumer electronics. There are many different energy storage technologies for different systems. Lithium-ion batteries - devices for converting and storing electricity - are used most often and are intensively studied for a wide range of applications. Endowed with attractive properties such as high energy density, long service life, small size and light weight, lithium-ion batteries have been identified as the most likely means to be used to store electricity in the future. To meet the demand for low-cost energy storage materials, many researchers are also interested in sodium ion batteries. The similarity of energy storage mechanisms between lithium and sodium ion batteries allowed their relatively rapid development. The anode plays a crucial role in batteries because its characteristics directly affect its electrochemical performance. However, anode materials for graphite and silicon lithium-ion batteries are not suitable for the sodium-ion battery system. Graphite provides low system capacity due to the mismatch of the size of the graphite layer of radius to sodium ions. As for silicon, the storage of sodium ions is achieved only in amorphous silicon. A key factor is the development of high-performance electrode materials for sodium ion batteries and the optimization of the architecture of the material of the anodes of lithium-ion batteries. Thus, the problem of studying materials for anodes of sodium and lithium-ion batteries is relevant and is essential to achieve their high performance. Thus, transition metal dichalcogenide films can be used as an anode material for sodium and lithium-ion batteries. The optimal filling of the SnS2 - based film anode material with Na and Li atoms was recorded, which was 75% when the movement of metal atoms was accompanied by the lowest energy costs. It is established that it is more expedient to intercalate Na atoms than Li at the anode on the basis of SnS2 material, because the total energy of the system during intercalation of Na atoms in the SnS2 layer is less than during intercalation of Li atoms. Peculiarities of charge redistribution on Se atoms of TaSe2 films with molecules of polymer electrolytes LiClO4 or (and) PEO as an anode material controlling the motion of lithium ions and modification of potential barriers to motion have been established; found that anodes based on TaSe2 films with molecules of polymer electrolyte PEO, TaSe2 with molecules of polymer electrolytes LiClO4/PEO has the lowest energy consumption of the system when overcoming energy barriers with intercalated Li atoms compared to the anode made of TaSe2 films without adding poly. Keywords: dichalcogenide transition metal films, anode lithium-ion batteries, anode sodium-ion batteries, Li atoms, Na atoms, electronic properties, electron density functional, pseudopotential from the first principles.