This disclosure relates to the technical field of carbon nanotubes, provides an ultra-long chiral carbon nanotube and a method for preparing the same. The ultra-long chiral carbon nanotube has a diameter of about 1.5 nm to 5.5 nm and has a length of about 100 mm to 650 mm, the ultra-long chiral carbon nanotube includes a double-walled carbon nanotube and a triple-walled carbon nanotube, and each layer of the ultra-long chiral carbon nanotube is semiconducting and has a helix angle greater than 10°.

The present disclosure provides an apparatus capable of continuously producing carbon nanotubes having high crystallinity, a low residual catalyst content and a high aspect ratio. The apparatus for producing carbon nanotubes includes: a reaction unit configured to synthesize carbon nanotubes (CNTs), a supply unit configured to supply a carbon source to the reaction unit through a supply pipe; and a collection unit configured to collect carbon nanotubes discharged from the reaction unit, wherein the reaction unit may include a chemical vapor deposition reactor.

The present invention proposes a process for purifying raw carbon nanotubes to obtain an content in metallic impurities comprised between 5 ppm and 200 ppm. The process includes an increase in the bulk density of the raw carbon nanotubes via compacting to produce compacted carbon nanotubes. The process further includes sintering the compacted carbon nanotubes by undergoing thermal treatment under gaseous atmosphere in order to remove at least a portion of the metallic impurities contained in the raw carbon nanotubes, and consequently producing purified carbon nanotubes. These purified carbon nanotubes are directly usable as electronic conductors serving as basis additive to an electrode material without requiring any subsequent purification step. The electrode material can then be used to manufacture an electrode destined to a lithium-ion battery.

A fibrous carbon nanostructure dispersion liquid having excellent dispersibility of fibrous carbon nanostructures is provided. A fibrous carbon nanostructure dispersion liquid comprises: fibrous carbon nanostructures with a tap density of 0.024 g/cm.sup.3 or less; and a solvent.

High-surface area carbon nanotubes having targeted, or selective, species of oxygen containing species levels, types and/or content on either or both of the interior and exterior of the tube walls are claimed. Such carbon nanotubes can have little to none inner tube surface oxygen containing species, or differing amounts and/or types of oxygen containing species between the tubes' inner and outer surfaces or amongst the carbon nanotubes. Additionally, such high-surface area carbon nanotubes or their assemblages may have greater lengths and diameters, creating useful mechanical, electrical, and thermal properties.

A process for growing carbon nanotubes includes making carbon nanotubes by flowing methane into a tube. The process also includes increasing pressure to a high predefined pressure for the carbon nanotubes and maintaining temperature at a low predefined temperature for the carbon nanotubes. The high pressure and low temperature produce carbon nanotubes within minutes.

A carbon nanotube composite is a carbon nanotube composite including one carbon nanotube and an amorphous carbon-containing layer that coats the carbon nanotube, the carbon nanotube having a D/G ratio of 0.1 or less, the D/G ratio being a ratio of a peak intensity of a D band to a peak intensity of a G band in Raman spectroscopic analysis with a wavelength of 532 nm, the carbon nanotube composite being fibrous and having a diameter of 0.1 m or more and 50 m or less.

A carbon purification method (10) and a carbon product are provided. The carbon purification method (10) includes providing (12) a carbon product having a catalyst content and/or impurities, performing (14) a hydrothermal acid digestion operation on the carbon product in an acid to dissolve the catalyst content and/or the impurities, and performing (16) a filtering operation to separate the dissolved catalyst content and/or the dissolved impurities from the carbon product.

Methods for characterizing a nanotube formulation with respect to one or more particular ionic species are disclosed. Within the methods of the present disclosure, this characterization provides control over the surface roughness (or smoothness) and the degree of rafting within a nanotube fabric formed form such a nanotube formulation. In one aspect, the present disclosure provides a nanotube formulation roughness curve (and methods for generating such a curve) that can be used to select a utilizable range of ionic species concentration levels that will provide a nanotube fabric with a desired surface roughness (or smoothness) and degree of rafting. In some aspects of the present disclosure, such a nanotube formulation roughness curve can be used adjust nanotube formulation prior to a nanotube formulation deposition process to provide nanotube fabrics that are relatively smooth with a low degree of rafting.

Applicability to a composite material with high purity and high strength, and a material requiring high conductivity or high thermal conductivity is enhanced. The present invention relates to a multi-walled carbon nanotube having two or more tubes of a graphene sheet where carbon atoms are arranged in a hexagonal honeycomb form, coaxially, wherein a diameter of an outermost wall based on observation of an image by a transmission electron microscope is 3 nm or more and 15 nm or less, and a length based on observation of an image of a scanning electron microscope is 1.0 mm or more, an aggregate of multi-walled carbon nanotubes and a method for preparing the multi-walled carbon nanotube.