Directly-prepared ultrahigh-purity carbon nanotube and preparation method thereof

Abstract

The invention discloses a directly-prepared ultrahigh-purity carbon nanotube and a preparation method thereof, belonging to the technical field of carbon nanotubes. Under the condition that purification is not required, the purity of the carbon nanotube is greater than 99.7 weight percent, the tube diameter is between 0.8 nanometer and 30 nanometers, the specific surface area is between 200 m<2> / g and 500 m<2> / g, the agglomeration density is between 30 kg / m<3> and 150 kg / m<3> and the agglomeration particle size is between 20 microns and 150 microns. A method for directly preparing the ultrahigh-purity carbon nanotube by adopting a chemical vapor deposition method comprises the following steps of: dispersing catalyst crystal grains generated with a liquid phase method onto the surface of an inert carrier, drying and baking; cracking hydrocarbon with 1-6 carbon atoms in a fluidized bed reactor to generate a carbon nanotube; and separating the inert carrier from the generated carbon nanotube at a higher air speed. The carbon nanotube obtained with the method has the purity between 99.7 percent and 99.9 percent, and has the advantages of high carbon nanotube quality, no need of removing impurities by acid treatment, low cost and easiness for amplification and preparation.

Description

technical field [0001] The invention belongs to the technical field of carbon nanotube preparation, in particular to a directly prepared ultrahigh-purity carbon nanotube and a preparation method thereof. Background technique [0002] Carbon nanotubes are a seamless tubular material formed by sp2 hybridized carbon coils. Due to the closed structure of the tube wall, no dangling bonds, and its huge aspect ratio, the electrical conductivity, thermal conductivity, and mechanical strength of carbon nanotubes, etc. Both are the highest values ​​of currently known materials, and the study of its preparation and application has important academic significance and application prospects. [0003] After nearly 20 years of development, chemical vapor deposition has become the most important method for preparing carbon nanotubes. The principle is: use nano-metal catalysts (mainly iron, cobalt, nickel, etc. loaded on porous carriers or Si substrates) to crack carbon sources (such as hydr...

AI Technical Summary

Problems solved by technology

Because metal impurities induce free radical reactions in rubber, tires age (strength deteriorates), which may induce vicious accidents of motor vehicles driving at high temperatures and at high speeds

However, metal impurities in lithium-ion batteries will cause lithium ions to move out and gradually generate larger dendrites, which will damage the diaphragm and cause short circuits in the battery, etc.

Obviously, the current direct preparation technology of carbon nanotubes is far from meeting this requirement.

The method of removing metal impurities by acid treatment or high-temperature evaporation can increase the purity of carbon nanotubes to 99.9%, but the cost will increase significantly and a large amount of waste acid will be produced (environmental pollution)

Moreover, after these treatments, carbon nanotubes are easy to agglomerate and difficult to disperse, which increases the difficulty of application