Preparation method and application of a carbon-nanotube-supported carbon-coated silicon-oxygen material

Abstract

The invention provides a preparation method and application of a carbon-nanotube-loaded carbon-coated silicon-oxygen material. The carbon-nanotube-loaded carbon-coated silicon-oxygen material uses carboxylated carbon nanotubes as a skeleton, and adopts an electrostatic adsorption method to make amino The nano-silica is adsorbed onto its surface, coated with a carbon source liquid phase, and after the solution penetrates into the silica, it goes through the pre-oxidation and carbonization stages, and then undergoes high-temperature reduction treatment in a mixed gas of hydrogen and argon for a certain period of time, and then Most of the silicon dioxide is etched away, and finally washed and dried by ball milling to obtain a carbon nanotube-loaded carbon-coated silicon-oxygen powder with a concrete structure similar to steel bars. The carbon in the carbon nanotube-loaded carbon-coated silicon-oxygen material prepared by the present invention is Nanotubes are fixed in carbon-coated silicon oxide, avoiding direct contact of carbon nanotubes, and fundamentally solving the problem of carbon nanotube agglomeration. Carbon-coated silicon oxide and carbon nanotubes form a reinforced concrete structure, which is conducive to electron transmission , to make up for the poor conductivity of silicon oxide.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery materials, and relates to a preparation method and application of a carbon nanotube-loaded carbon-coated silicon-oxygen material. Background technique [0002] The theoretical gram capacity of silicon-oxygen materials is several times that of graphite. Therefore, adding silicon-oxygen materials to lithium-ion negative electrode materials is one of the most effective ways to increase the energy density of batteries. However, compared with graphite, silicon-oxygen materials have poor electrical conductivity and low volume. The expansion is large, and eventually the cycle stability is far less than that of graphite. At present, the industry is mainly improved by matching carbon nanotubes, electrolyte optimization, binder screening, and compounding different graphites. Among them, carbon nanotubes can significantly improve the silicon-oxygen cycle performance because of their long diameter ratio, a...

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Problems solved by technology

[0006] The object of the present invention is to provide a preparation method and application of a carbon nanotube-loaded carbon-coated silicon-oxygen material. The carbon nanotube-loaded carbon-coated silicon-oxygen material uses carboxylated carbon nanotubes as a skeleton and adopts an electrostatic adsorption method The aminated nano-silica is adsorbed to its surface, coated with a carbon source liquid phase, and after the solution penetrates into the silica, it goes through the pre-oxidation and carbonization stages, and then undergoes high-temperature reduction treatment in a hydrogen-argon mixed gas for a certain period of time. , then etch away most of the silicon dioxide, and finally wash, dry and ball mill to obtain a carbon nanotube-loaded carbon-coated silicon-oxygen powder with a concrete structure similar to steel bars. Among the carbon nanotube-loaded carbon-coated silicon-oxygen materials prepared by the present invention The carbon nanotubes are fixed in carbon-coated silicon oxide, avoiding direct contact of carbon nanotubes, and fundamentally solving the problem of agglomeration of carbon nanotubes. Carbon-coated silicon oxide and carbon nanotubes form a reinforced concrete structure, which is beneficial to Electron transport, making up for the poor conductivity of silicon oxide

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