Khomenko V. Scientific fundamentals of technologies for creation of polymer nanostructured composite materials with record electroactive and barrier properties

Nanotechnologies such as nanoparticles, nanocomposites, or nanostructured materials have a great potential to make a significant impact on the performance of electrochemical power sources. This thesis solves an important scientific and practical problem of creating the composite materials based on polyfluorocarbon material for primary lithium battery. Scientific ideas about the mechanism of electroreduction of oxygen on the surface of non-platinum catalysts are developed. Methods for obtaining catalysts based on nanostructured carbon materials and various types of inorganic compounds, namely spinels of the AB2O4 type, have been developed. The process of oxidation and reduction of oxygen in the aprotic electrolyte was investigated in this work. The obtained data indicate the formation in the gas diffusion electrode of insoluble products that block the surface of the substrate and the catalyst. As a result, the efficiency of the catalyst in the aprotic electrolyte is much lower than in the aqueous one. The decisive factor in the efficiency of the electrode of the lithium-air battery is its specific surface area, which should ensure maximum accumulation of insoluble oxygen reduction products. It was founded that the electrochemical activity of bimetallic composite catalysts in acid solutions was almost similar to the pure Pt. The obtained composite catalysts based on Pt-Cu on carbon materials show high activity in the oxidation of methanol, and therefore can be successfully used in fuel cells. Obtaining catalysts based on nanostructured carbon materials and various types of inorganic compounds were tested in models of metal-air power sources. It is established that the characteristics of the element mainly depend on the composition of the electrolyte. In particular, the characteristics of air-zinc elements are limited by the behavior of the zinc electrode. Using the results of the dissertation, technologies for manufacturing the composite electrodes of lithium-ion batteries have been developed and improved. The technology of obtaining the electrodes on the basis of a mixture of an aqueous emulsion of polymers is developed. Such electrodes are not inferior in electrochemical characteristics to electrodes made using PVDF solutions (and in some cases surpass them), and also make production more environmentally friendly and can significantly reduce the cost of production of lithium-ion batteries (LIB). Coatings capable of recycling lithium with a specific capacity of up to 3600 mAh/g are obtained in this work. High stability of graphite-based composite materials during their cycling with a capacity of 700 mAh/g is shown, which is twice the capacity of traditional graphite anodes. Various carbon materials for lithium-ion battery anodes were investigated. The technology of purification of Ukrainian graphite for the creation of active material is offered. The obtained results indicate the influence of the nature of graphite materials. The thesis proposes and experimentally implements the idea that the characteristics of the cathode material LIB can be significantly improved by forming a barrier coating on the particles of the active material with the NASICON structure compound, which is a solid electrolyte. Various electrochemical systems of lithium-ion capacitors have been developed and studied. Hybrid electrochemical capacitors have a higher (3-10 times) specific energy than classical symmetrical capacitors of the double electric layer based on activated carbon. This work deal with investigates and compares the electromagnetic properties of several carbon and graphite materials and evaluates the effectiveness of usage the nanomaterials in order to create some composites for protection against electromagnetic radiation. For the first time, the positive influence of dispersed nanomaterial on the formation of the structure of the protective coating and the improvement of its electrophysical properties is shown. The shielding coefficients of the manufactured composite samples were established at the level of -30… -50 dB in the frequency range of 0.3-18 GHz, the thickness of which did not exceed 300 μm. This result allows them to be successfully used for the production of protective materials.