Graphene has been used in nanocomposites as constituents/doping in plastics or epoxy providing dramatic enhancement of the mechanical properties but have not progressed past the laboratory level novelty. This invention can provide a graphene based composite structure with a density less that 1.9 g/cm.sup.3 for a fiber, yarn, rope or cable and a density less that 1.5 g/cm.sup.3 for a sheet both structure have tensile and shear strength greater than either Aluminum or Steel; thus providing a graphene material that is both much lighter and stronger.

A flexible all-solid state supercapacitor is provided that includes a first electrode and a second electrode, and a flexible nanofiber web, where the flexible nanofiber web connects the first electrode to the second electrode, where the flexible nanofiber web includes a plurality of flexible nanofibers, where the flexible nanofiber includes a hierarchal structure of macropores, mesopores and micropores through a cross section of the flexible nanofiber, where the mesopores and the micropores form a graded pore structure, where the macropores are periodically distributed along the flexible nanaofiber and within the graded pore structure.

A flexible all-solid state supercapacitor is provided that includes a first electrode and a second electrode, and a flexible nanofiber web, where the flexible nanofiber web connects the first electrode to the second electrode, where the flexible nanofiber web includes a plurality of flexible nanofibers, where the flexible nanofiber includes a hierarchal structure of macropores, mesopores and micropores through a cross section of the flexible nanofiber, where the mesopores and the micropores form a graded pore structure, where the macropores are periodically distributed along the flexible nanaofiber and within the graded pore structure.

The invention relates to an oxygen and nitrogen co-doped polyacrylonitrile-based carbon fiber and a preparation method thereof. The oxygen and nitrogen co-doped polyacrylonitrile-based carbon fiber is prepared by electrochemical modification of a raw-material polyacrylonitrile-based carbon fiber, such that the surface thereof has an active layer formed by oxygen-containing active functional groups and nitrogen-containing active functional groups, wherein the nitrogen-containing active functional groups are obtained by activation of the doped nitrogen inherently contained in the raw-material polyacrylonitrile-based carbon fiber by means of electrochemical modification. The method for preparing the oxygen and nitrogen co-doped polyacrylonitrile-based carbon fiber comprises the following steps: placing the raw-material polyacrylonitrile-based carbon fiber in an electrolyte solution, subjecting it to cyclic treatment between electrochemical oxidation and electrochemical reduction, and thus obtaining the oxygen and nitrogen co-doped polyacrylonitrile-based carbon fiber. The oxygen and nitrogen co doped polyacrylonitrile based carbon fiber of the present invention has both the pseudo capacitive properties for oxidation reduction reactions and electrocatalytic properties for the cathodic oxygen reduction reaction.

The invention relates to an oxygen and nitrogen co-doped polyacrylonitrile-based carbon fiber and a preparation method thereof. The oxygen and nitrogen co-doped polyacrylonitrile-based carbon fiber is prepared by electrochemical modification of a raw-material polyacrylonitrile-based carbon fiber, such that the surface thereof has an active layer formed by oxygen-containing active functional groups and nitrogen-containing active functional groups, wherein the nitrogen-containing active functional groups are obtained by activation of the doped nitrogen inherently contained in the raw-material polyacrylonitrile-based carbon fiber by means of electrochemical modification. The method for preparing the oxygen and nitrogen co-doped polyacrylonitrile-based carbon fiber comprises the following steps: placing the raw-material polyacrylonitrile-based carbon fiber in an electrolyte solution, subjecting it to cyclic treatment between electrochemical oxidation and electrochemical reduction, and thus obtaining the oxygen and nitrogen co-doped polyacrylonitrile-based carbon fiber. The oxygen and nitrogen co doped polyacrylonitrile based carbon fiber of the present invention has both the pseudo capacitive properties for oxidation reduction reactions and electrocatalytic properties for the cathodic oxygen reduction reaction.

A flexible all-solid state supercapacitor is provided that includes a first electrode and a second electrode, and a flexible nanofiber web, where the flexible nanofiber web connects the first electrode to the second electrode, where the flexible nanofiber web includes a plurality of flexible nanofibers, where the flexible nanofiber includes a hierarchal structure of macropores, mesopores and micropores through a cross section of the flexible nanofiber, where the mesopores and the micropores form a graded pore structure, where the macropores are periodically distributed along the flexible nanaofiber and within the graded pore structure.

A method for manufacturing metal oxide-grown carbon fibers including immersing carbon fibers in a solution for forming a metal oxide seed layer and electrodepositing a metal oxide seed on the surfaces of carbon fibers, or irradiating microwave thereto to form a metal oxide seed layer, and irradiating microwave to the metal oxide seed layer-formed carbon fibers to grow metal oxide. The method for manufacturing metal oxide-grown carbon fibers can reduce process time, and improve process energy efficiency and production efficiency. The method for manufacturing metal oxide-grown carbon fibers can offer metal oxide-grown carbon fibers with improved interfacial shear stress.

Provided is an apparatus for producing a carbon nanotube fiber. The apparatus includes: a vertical reactor having a reaction zone; an inlet through which a spinning solution is introduced into the bottom of the reaction zone of the reactor; an inlet through which a carrier gas is introduced into the bottom of the reaction zone of the reactor; heating means for heating the reaction zone; and a discharge unit disposed on the top of the reaction zone and through which a carbon nanotube fiber is discharged from the reactor. The spinning solution entering the reaction zone through the spinning solution inlet is carbonized and graphitized while ascending from the bottom of the reaction zone by the carrier gas entering through the carrier gas inlet, to form a carbon nanotube fiber consisting of continuous aggregates of carbon nanotubes. Further provided is a carbon nanotube fiber produced using the apparatus. The carbon nanotube fiber is long and exhibits high electrical conductivity, tensile strength, and elasticity. Due to these advantages, the carbon nanotube fiber is expected to find a variety of applications, including multifunctional composite materials, deformation/damage sensors, transmission cables, and electrochemical devices, for example, microelectrode materials for biological substance detection, supercapacitors, and actuators.

Provided is an apparatus for producing a carbon nanotube fiber. The apparatus includes: a vertical reactor having a reaction zone; an inlet through which a spinning solution is introduced into the bottom of the reaction zone of the reactor; an inlet through which a carrier gas is introduced into the bottom of the reaction zone of the reactor; heating means for heating the reaction zone; and a discharge unit disposed on the top of the reaction zone and through which a carbon nanotube fiber is discharged from the reactor. The spinning solution entering the reaction zone through the spinning solution inlet is carbonized and graphitized while ascending from the bottom of the reaction zone by the carrier gas entering through the carrier gas inlet, to form a carbon nanotube fiber consisting of continuous aggregates of carbon nanotubes. Further provided is a carbon nanotube fiber produced using the apparatus. The carbon nanotube fiber is long and exhibits high electrical conductivity, tensile strength, and elasticity. Due to these advantages, the carbon nanotube fiber is expected to find a variety of applications, including multifunctional composite materials, deformation/damage sensors, transmission cables, and electrochemical devices, for example, microelectrode materials for biological substance detection, supercapacitors, and actuators.

The present invention relates to a method for preparing a carbon nanofiber composite, and a carbon nanofiber composite prepared thereby. The method for preparing a carbon nanofiber composite provided by the present invention has reduced costs and is economical and efficient compared with a convention method for preparing a carbon nanofiber composite. In addition, the carbon nanofiber composite of the present invention can provide remarkable decomposition performance of organic pollutants, and a carbon nanofiber composite prepared by the preparation method of the present invention can be used in an electrode for an electric double-layer supercapacitor, a fuel cell electrode, a filter, a hydrogen storage material, and the like.