Shyyko L. Synthesis, structure and electrochemical properties of double hierarchical matrices carbon - metal oxides and sulfides

The thesis presents detailed description of methods of MoS2/C nanocomposite obtaining and investigation of their macro- and microstructure and properties. It was established that hydrothermal method together with the use of additional agents is an easy way to manage physical and chemical properties of synthesized materials. In particular, using the same precursors and under the same conditions, but adding various surfactants or mesoporous carbon as a temlate, results in contrast in morphology, size, composition and divergent values and nature of electrical conductivity of the nanocomposites, which in turn determines the distinct areas of their application. In particular, multilayered nanospheres with double hierarchical structure with alternating layers of MoS2 and C obtained using the cationic surfactant - cetyltrimethylammonium bromide, showed extremely high specific characteristics as a basis for electrode of lithium power sources and effectiveness as an additive to engine oil for reducing friction between engineering surfaces - the critical point of destruction has dropped 10 times while the friction coefficient was reduced by 37% at 0.1% mass concentration of the nanocomposite. Meantime, the addition of nonionic surfactant Triton X-100 provides sponge-like composite MoS2/C, which is a potential material for supercapacitors and as a dry lubricant. In turn, the composite molybdenum disulfide / mesoporous carbon is a good solution to improve the supercapacitor capacity, combining features of the charge accumulation on the electric double layer and pseudocapacity of eletrochemical reactions. The combination with carbon gave a rise to synergetic effect between components. Carbon, being a donor of electrons to the metal sulfide or oxide, increased the electrical conductivity of the synthesized nanocomposites. Also, in the work the analysis of the impact of local heat treament on electrochemical characteristics of MoS2/C and TiO2/C is presented. It was proved that injected morphological and structural features created new active sites for hosted ions, increasing specific capacity several times in compare with initial materials.