20640 results about "Graphite oxide" patented technology

Disclosed is a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm, and often between 0.34 nm and 1.02 nm. The method comprises: (a) subjecting the layered material in a powder form to a halogen vapor at a first temperature above the melting point or sublimation point of the halogen at a sufficient vapor pressure and for a duration of time sufficient to cause the halogen molecules to penetrate an interlayer space of the layered material, forming a stable halogen-intercalated compound; and (b) heating the halogen-intercalated compound at a second temperature above the boiling point of the halogen, allowing halogen atoms or molecules residing in the interlayer space to exfoliate the layered material to produce the platelets. Alternatively, rather than heating, step (a) is followed by a step of dispersing the halogen-intercalated compound in a liquid medium which is subjected to ultrasonication for exfoliating the halogen-intercalated compound to produce the platelets, which are dispersed in the liquid medium. The halogen can be readily captured and re-used, thereby significantly reducing the impact of halogen to the environment. The method can further include a step of dispersing the platelets in a polymer or monomer solution or suspension as a precursor step to nanocomposite fabrication.

The present invention relates to graphite alkene iron lithium phosphate positive active material, a preparing method thereof, and a lithium ion twice battery based on the graphite alkene modified iron lithium phosphate positive active material. Graphite alkene and iron lithium phosphate are dispersed into water solution to be mixed evenly by stirring and ultra audible sound, then, are dried to obtain iron lithium phosphate material compounded by the graphite alkene and the iron lithium phosphate to be annealed by high temperature, and finally, the graphite alkene modified iron lithium phosphate positive active material is obtained. Compared with traditional carbon coated and conductive polymeric adulteration modified lithium batteries, the lithium ion twice battery based on the graphite alkene modified iron lithium phosphate positive active material has the advantages of high battery capacity, good charging-discharging circulating performance, long life and high circulating stability, and has great utility value.

A gas diffusion barrier contains a polymer matrix and a functional graphene which displays no signature of graphite and / or graphite oxide, as determined by X-ray diffraction.

The present invention provides a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm. The method comprises (a) dispersing particles of graphite, graphite oxide, or a non-graphite laminar compound in a liquid medium containing therein a surfactant or dispersing agent to obtain a stable suspension or slurry; and (b) exposing the suspension or slurry to ultrasonic waves at an energy level for a sufficient length of time to produce separated nano-scaled platelets. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

A polymer composition, containing a polymer matrix which contains an elastomer; and a functional graphene which displays no signature of graphite and / or graphite oxide, as determined by X-ray diffraction, exhibits excellent strength, toughness, modulus, thermal stability and electrical conductivity.

The invention firstly discloses an oxidized graphene or graphene / inorganic particle core / shell material which is formed by electrostatic self-assembly, wherein inorganic particles are taken as the core of the material, oxidized graphene or graphene is taken as a shell layer, and the content of the oxidized graphene or the graphene is 0.1-2wt% of that of the inorganic particles. The invention alsodiscloses a preparation method of the oxidized graphene or graphene / inorganic particle core / shell material. Therefore, a new species is added for outer-coated inorganic powder materials and the application space of the inorganic particles is expanded; furthermore, the electrostatic self-assembly technology is further applied to the preparation of the oxidized graphene or graphene-inorganic powderhybrid material, and the method simultaneously has the characteristics of being mature and environmentally-friendly in process, being simple to operate, having no need of complex equipment, being easy for realization of large-scale production and the like.

The invention discloses a method for preparing a graphene-doped anode material for lithium-ion batteries. The main component of the anode material is lithium iron phosphate nanoparticles. The method comprises the following steps of: firstly preparing the graphene, graphene oxide, and intercalation graphene respectively; secondly, doping the mixture of the graphene, the graphene oxide and the intercalation graphene in the synthetic material of the lithium iron phosphate nanoparticles or directly mixing the lithium iron phosphate nanoparticles and the intercalation graphene, the graphene oxide,or chemically reduced graphene after the preparation of lithium iron phosphate nanoparticles; and finally, synthesizing the graphene or graphene oxide bridged or lithium iron phosphate nanoparticle-clad material after the treatment of drying, filtering, eluting, re-drying, and annealing. The lithium iron phosphate nanoparticles prepared by the method of the invention are characterized by the capability of greatly improving electron conductivity and providing the lithium-ion batteries anode material having the advantages of simple processing technique, low cost, high capacity and safety for lithium-ion batteries.

A graphene-on-oxide substrate according to the present invention includes: a substrate having a metal oxide layer formed on its surface; and, formed on the metal oxide layer, a graphene layer including at least one atomic layer of the graphene. The graphene layer is grown generally parallel to the surface of the metal oxide layer, and the inter-atomic-layer distance between the graphene atomic layer adjacent to the surface of the metal oxide layer and the surface atomic layer of the metal oxide layer is 0.34 nm or less. Preferably, the arithmetic mean surface roughness Ra of the metal oxide layer is 1 nm or less.