The carbon nanotubes according to the present invention can provide higher conductivity by allowing the BET and crystal size to satisfy the conditions expressed by formula 1 below, and consequently, can improve the conductivity of a carbon composite material containing the carbon nanotubes.

L.sub.c[Specific surface area of CNT (cm.sup.2/g)].sup.1/2>80[Formula 1] wherein, L.sub.c is crystal size measured by X-ray diffraction.

A carbon nanotube film includes an assembly of a plurality of carbon nanotubes, wherein the plurality of carbon nanotubes includes one or more carbon nanotubes having at least partially collapsed structures. A method for producing a carbon nanotube film includes forming a carbon nanotube film by removing a solvent from a carbon nanotube dispersion liquid containing the solvent, a dispersant, and a plurality of carbon nanotubes including one or more carbon nanotubes having at least partially collapsed structures.

The invention discloses the application of carbon nanotube assemblies to the preparation of a nanocarbon impact-resistant material. The carbon nanotube assembly is a macrostructure provided with at least one continuous surface, a plurality of carbon nanotubes are densely distributed in the continuous surface, and at least partial segments of at least part of the multiple carbon nanotubes continuously extend in the continuous surface. The invention further discloses a preparation method of the nanocarbon impact-resistant material. The nanocarbon impact-resistant material has an excellent protection effect, has the advantages of being light, good in flexibility, wide in tolerable temperature range, capable of being bent freely, good in fitness, breathable, adaptable to heat-moisture balance of human bodies, good in wearing comfort and the like, and can be widely applied to bullet-proof materials, stab-proof materials and explosion-proof materials.

Provided is a method for efficiently producing a carbon nanotube dispersion liquid in which less-damaged carbon nanotubes are highly dispersed. The method for producing a carbon nanotube dispersion liquid includes: (A) obtaining a carbon nanotube dispersion liquid by applying a shear force to a coarse dispersion liquid that includes carbon nanotubes having a specific surface area of 600 m.sup.2/g or more to whereby disperse the carbon nanotubes, wherein the step (A) includes at least one of applying a back pressure to the carbon nanotube dispersion liquid and cooling the carbon nanotube dispersion liquid.

A composition for a thermoelectric conversion element that enables a thermoelectric conversion element to fully exhibit excellent thermoelectric conversion characteristics is provided. A composition for a thermoelectric conversion element comprises: metal nanoparticle-supporting carbon nanotubes, a resin component; and a solvent.

Provided is a fibrous carbon nanostructure dispersion liquid having excellent fibrous carbon nanostructure dispersibility. The fibrous carbon nanostructure dispersion liquid contains a solvent and one or more fibrous carbon nanostructures that exhibit a convex upward shape in a t-plot obtained from an adsorption isotherm.

An electromagnetic wave absorption material comprises surface-treated fibrous carbon nanostructures obtainable by treating surfaces of fibrous carbon nanostructures, wherein at surfaces of the surface-treated fibrous carbon nanostructures, an amount of an oxygen element is 0.030 times or more and 0.300 times or less an amount of a carbon element and/or an amount of a nitrogen element is 0.005 times or more and 0.200 times or less the amount of the carbon element.

Provided is a method for preparing a carbon nanotube dispersion including preparing a carbon nanotube bundle; post-processing the carbon nanotube bundle to reduce an average length of the carbon nanotube bundle to 50 ?m or less; and dispersing the post-processed carbon nanotube bundle in a solution.

The present disclosure is directed to providing a carbon film having an excellent shield performance against electromagnetic waves. The carbon film of the present disclosure is a carbon film made of a carbon nanotube assembly, wherein a pore distribution curve of the carbon film indicating the relationship between the pore size and the Log differential pore capacity obtained from an adsorption isotherm at 77 K of liquid nitrogen based on the Barrett-Joyner-Halenda method has a peak in which the Log differential pore capacity is maximized within a pore size range of 10 nm or more and 100 nm or less, and the value of the Log differential pore capacity at the peak is 1.2 cm.sup.3/g or more.

The present disclosure relates to a carbon nanotube dispersion including carbon nanotubes, a first dispersant having an amide group, a second dispersant having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups, and sulfur. The present disclosure also relates to a method of preparing the dispersion, an electrode slurry composition including the dispersion, an electrode including the electrode slurry composition, and a secondary battery including the electrode.