Due to the growing consumption of electrical energy, the requirements for storage devices are becoming more strict: light weight, more energy production, high cycling stability, increased power, etc. New electrode materials are being developed to meet modern challenges.
Today, there are not many commercially suitable anode materials for lithium-ion batteries: graphite and lithium titanate (Li4Ti5O12). The theoretical specific capacity of the first one is 372 mAh/g, which decreases sharply with increasing of charge-discharge currents, especially during operating at negative temperatures. Lithium titanate does not have such disadvantages, but its specific capacity is lesser (175 mAh/g), and the discharge voltage is higher (1.55 V).
One of the most promising studied anode materials are transition metal oxides, whose theoretical capacities are much larger than one for graphite: CoO - 716 mAh/g, Co3O4 - 890 mAh/g, Fe3O4 - 924 mAh/g. The obtained values reach theoretical only at low operating rates and only in complex composite electrodes that require special production conditions. Oxide nanoparticles are synthesized by the several methods: chemical condensation, pyrolysis, precipitation from colloidal solutions, hydrothermal method, etc. The result is particles larger than 20 nm in size. And the larger the specific surface area of the material, the better characteristics it is able to demonstrate.
On the other hand, for the synthesis of ultrasmall nanomaterials (size up to 10 nm), plasma chemical synthesis and its variant – microplasma electrolysis (low-temperature plasma electrolysis) is known, which allow to control flexibly the composition, size and morphology of particles. As a result, stable colloidal solutions are obtained that can be used directly (without pre-drying) for the preparation of electrodes, which will reduce the proportion of agglomerated particles and improve electrochemical characteristics.
Method of low-temperature plasma electrolysis has proven itself well for the synthesis of nanoscale metals, alloys, oxides, nitrides, carbides and other inorganic compounds and has only recently been used for the synthesis of organic compounds (in particular, for polymerization of dopamine or metal-organic polymer HKUST-1).
This research is aimed to development of transition metal oxide composites synthesized by low - temperature plasma electrolysis with conducting polymers for application in energy storage devices such as lithium-ion batteries and supercapacitors. In the course of this work, the behavior of a plasma discharge over a liquid containing monomers of conducting polymers will be studied; attempts will be made to produce semiconductor composites with simultaneous electrochemical polymerization of polymers on their surface or in the solution during low-temperature plasma electrolysis; composites of semiconductors with conducting polymers will be also made by chemical or electrochemical polymerization of monomers in a colloidal solution after microplasma electrolysis. The procedure for preparing composite materials will be optimized, which will allow it to be scaled up for industrial applications in the future.
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