Mandzyuk V. Structural-morphological and electrochemical properties of turbostratic carbon and composite materials SiO2-C, Al2O3-C.

The interconnections between the conditions of obtaining turbostratic carbon materials, SiO2-C, Al2O3-C composites, and their structural-morphological, electroconductive and electrochemical properties are established in the thesis. The mechanisms of electrochemical processes passing in the devices of electric energy generation and accumulation with electrodes on their basis are revealed.It is find out that the structure of porous carbon materials (PCM) obtained by the hydrothermal carbonization of plant material at the first structural level was formed by mass fractal aggregates formed from primary carbon nanoclusters of 3.0-4.8 nm in size and surface fractal aggregates. The increase in the carbonization temperature results in decrease in the mass fractals size (Dv = 2.65-2.00), an increase in the dimension of surface fractals (Ds = 2.10-2.60) with a simultaneous decrease in the surface fractal dimension of the open porous structure (Ds = 2.57-2.17), indicating the formation of a smooth (non-fractal) surface.The optimal regimes of obtaining (carbonization temperature 750°C) and thermal modification (temperature 400-500°C, time 2.5 hours) of the PCMs have been selected, at which lithium power source has the maximum specific capacity (~ 1510 mA•h/g) and specific energy (~ 1590 W•h/kg).It was found for the first time that carbonized materials obtained by thermal decomposition of glucose, saccharose and lactose in an inert atmosphere lose 55-75 % of their mass at further heating to a temperature of 1000°C. This is due to the formation in the material of small carbinide clusters C4H2O, C5HO2 or C6H5O, C6H6O2 or C9H2, which is separated from the carbon matrix at heating and goes into the gas phase. The maximum intensity of the sublimation process is recorded at 270-280°C.It is set that the texture of the material obtained from lactose is formed from lamellar crystallites of 0.4 nm in thickness and 0.4-5 nm in size of leaves, which provides them with the highest value of specific electrical conductivity (147.5 Ohm-1∙m-1) at an activation temperature of 1000°C. It is shown that electrochemical capacitors formed on the basis of saccharide-derived carbons have a capacity of 160 F/g at a discharge current of 10 mA.