Described here is a metal-carbon composite, comprising (a) a porous three-dimensional scaffold comprising one or more of carbon nanotubes, graphene and graphene oxide, and (b) metal nanoparticles disposed on said porous scaffold, wherein the metal-carbon composite has a density of 1 g/cm.sup.3 or less, and wherein the metal nanoparticles account for 1 wt. % or more of the metal-carbon composite. Also described are methods for making the metal-carbon composite.

The present invention relates to a method for preparing graphene oxide by cutting an end face of a 3-dimensional carbon-based material by electrochemical oxidation and the graphene oxide prepared by the method. The method comprises: connecting a piece of a 3-dimensional carbon-based material as an electrode and another piece of a 3-dimensional carbon-based material or inert material as another electrode to the two electrodes of a DC power supply respectively, wherein an end face of at least one piece of a 3-dimensional carbon-based material serves as the working face and is positioned in contact and parallel with the liquid surface of an electrolyte solution; then electrifying the two pieces for electrolysis, during which the working zone for the end face serving as the working face is between −5 mm below and 5 mm above the liquid surface of the electrolyte solution; and intermittently or continuously controlling the end face within the working zone, such that the graphite lamella on the end face of the at least one piece of the 3-dimensional carbon-based material as an electrode is expansion-exfoliated and cut into graphene oxide by electrochemical oxidation, to obtain a graphene oxide-containing electrolyte solution. The method has a higher expansion-based exfoliating and cutting ability by oxidation, and can produce high-quality graphene oxide having fewer layers and more uniform particle-size distribution with low energy consumption and no contamination.

An improved method for concentrating dispersions of graphene oxide, coating a substrate with a layer of a graphene oxide solution, and producing a supported graphene membrane stabilised by controlled deoxygenation; and graphene-based membranes that demonstrate ultra-fast water transport, precise molecular sieving of gas and solvated molecules, and which show great promise as novel separation platforms.

An interconnected corrugated carbon-based network comprising a plurality of expanded and interconnected carbon layers is disclosed. In one embodiment, each of the expanded and interconnected carbon layers is made up of at least one corrugated carbon sheet that is one atom thick. In another embodiment, each of the expanded and interconnected carbon layers is made up of a plurality of corrugated carbon sheets that are each one atom thick. The interconnected corrugated carbon-based network is characterized by a high surface area with highly tunable electrical conductivity and electrochemical properties.

Methods of making a microscale, free-standing, 3D, polyhedral, hollow, GO (or other graphene-based) structure using an origami-like self-folding approach. The origami-like self-folding process allows for easy control of size, shape, and thickness of graphene-based membranes, which, in turn, permits fabrication of freestanding 3D microscale polyhedral GO structures for example. With the 3D GO, a novel optical switching behavior is created, resulting from a combination of the geometrical effect of the 3D hollow structure and the water-permeable multi-layered GO membrane that affect the optical paths.

The present disclosure provides supercapacitors that may avoid the shortcomings of current energy storage technology. Provided herein are electrochemical systems, comprising three dimensional porous reduced graphene oxide film electrodes. Prototype supercapacitors disclosed herein may exhibit improved performance compared to commercial supercapacitors. Additionally, the present disclosure provides a simple, yet versatile technique for the fabrication of supercapacitors through the direct preparation of three dimensional porous reduced graphene oxide films by filtration and freeze casting.

The present disclosure provides supercapacitors that may avoid the shortcomings of current energy storage technology. Provided herein are electrochemical systems, comprising three dimensional porous reduced graphene oxide film electrodes. Prototype supercapacitors disclosed herein may exhibit improved performance compared to commercial supercapacitors. Additionally, the present disclosure provides a simple, yet versatile technique for the fabrication of supercapacitors through the direct preparation of three dimensional porous reduced graphene oxide films by filtration and freeze casting.

There are provided a graphene having an oxygen atom content in a predetermined range or less and a carbon/oxygen weight ratio in a specific range to show excellent electrical and thermal conductivity properties, and a barrier property, and a method and an apparatus for preparing the graphene having excellent electrical and thermal conductivity properties and a barrier property by using a subcritical-state fluid or a supercritical-state fluid. According to the method and the apparatus for preparing the graphene, impurities such as graphene oxide, and the like, may be effectively removed, such that uniformity of the graphene to be prepared may be increased, and therefore, the graphene which is highly applicable as materials throughout the industry may be mass-produced.

The disclosure provides methods for producing Li.sub.2S-graphene oxide (Li.sub.2S-GO) composite materials. The disclosure further provides for the Li.sub.2S-GO made therefrom, and the use of these materials in lithium-sulfur batteries.

A method of producing dispersed of high quality graphene/graphite oxides in a powder matrix to then be reacted to form a composite. Where the powders have similar hydrophobicity and the graphene/graphite oxides has minimal surface oxidation or minimal epoxy group and where the powders are sonically mixed.