The present disclosure relates to a process for preparing carbon fibers. The process involves blending a carbon nano-material with a carbon material to obtain a homogenous blend, heating the homogenous blend to obtain mesophase pitch having particles with reduced mesophase sphere size followed by spinning the mesophase pitch to obtain the pitch fibers. The pitch fibers are then carbonized to obtain the carbon fibers. The carbon fibers prepared by the process of the present disclosure have improved tensile properties as compared to the conventional pitch based carbon fibers.

A positive electrode active material having a core/shell structure, which includes a sulfur-carbon composite containing thermally expanded-reduced graphene oxide, a carbon material as a core, and carbon nanotubes as a shell. A method for preparing a positive electrode active material having a core/shell structure for a lithium secondary battery, including the steps of thermally expanding graphene oxide by heat treatment at a temperature in a range of 300° C. to 500° C. to prepare a thermally-expanded graphene oxide. Then, reducing the thermally-expanded graphene oxide by heat treatment at a temperature in a range of 700° C. to 1200° C. to prepare a thermally expanded-reduced graphene oxide. Next, mixing the thermally expanded-reduced graphene oxide and sulfur to prepare a sulfur-carbon composite. Last, mixing the sulfur-carbon composite and carbon nanotubes to form carbon nanotubes on a surface of the sulfur-carbon composite.

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 μm or more and 50 μm or less.

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 μm or more and 50 μm or less.

The embodiments of the present disclosure relate to a method, system and composition producing a magnetic carbon nanomaterial product that may comprise carbon nanotubes (CNTs) at least some of which are magnetic CNTs (mCNTs). The method and apparatus employ carbon dioxide (CO.sub.2) as a reactant in an electrolysis reaction in order to make mCNTs. In some embodiments of the present disclosure, a magnetic additive component is included as a reactant in the method and as a portion of one or more components in the system or composition to facilitate a magnetic material addition process, a carbide nucleation process or both during the electrosynthesis reaction for making magnetic carbon nanomaterials.

The embodiments of the present disclosure relate to a method, system and composition producing a magnetic carbon nanomaterial product that may comprise carbon nanotubes (CNTs) at least some of which are magnetic CNTs (mCNTs). The method and apparatus employ carbon dioxide (CO.sub.2) as a reactant in an electrolysis reaction in order to make mCNTs. In some embodiments of the present disclosure, a magnetic additive component is included as a reactant in the method and as a portion of one or more components in the system or composition to facilitate a magnetic material addition process, a carbide nucleation process or both during the electrosynthesis reaction for making magnetic carbon nanomaterials.

According to a first aspect of the invention, a method for producing a metal-CNT composite material is proposed. The method includes providing a layer of CNT by depositing CNT coated with a polyphenol or poly(catecholamine) coating and filling the interstices of the carbon nanotubes layer with a metal so as to form a metal matrix, in which CNT are embedded. The filling is effected by electrode position or by electroless deposition. The polyphenol or poly(catecholamine) coating is crosslinked by metal ions, the metal ions promoting, as metal seeds, adhesion and/or growth of the metal matrix during the filling step. A further aspect of the invention relates to the metal-CNT composite obtainable by the method.

According to a first aspect of the invention, a method for producing a metal-CNT composite material is proposed. The method includes providing a layer of CNT by depositing CNT coated with a polyphenol or poly(catecholamine) coating and filling the interstices of the carbon nanotubes layer with a metal so as to form a metal matrix, in which CNT are embedded. The filling is effected by electrode position or by electroless deposition. The polyphenol or poly(catecholamine) coating is crosslinked by metal ions, the metal ions promoting, as metal seeds, adhesion and/or growth of the metal matrix during the filling step. A further aspect of the invention relates to the metal-CNT composite obtainable by the method.

An apparatus and method for transferring nanofiber structures (e.g., nanofiber films, nanofiber sheets, stacks of nanofiber grids, nanofiber films, nanofiber sheets, and combinations thereof) between various substrates are described. The techniques described use a soluble layer on a substrate that is subsequently dissolved, thus freeing the nanofiber structure from the substrate. This liquid phase techniques preserves the mechanical integrity and the purity of the nanofiber structures.

An apparatus and method for transferring nanofiber structures (e.g., nanofiber films, nanofiber sheets, stacks of nanofiber grids, nanofiber films, nanofiber sheets, and combinations thereof) between various substrates are described. The techniques described use a soluble layer on a substrate that is subsequently dissolved, thus freeing the nanofiber structure from the substrate. This liquid phase techniques preserves the mechanical integrity and the purity of the nanofiber structures.