Physical method for preparing grapheme

Abstract

The invention discloses a physical method for preparing grapheme. The method comprises the steps of powder and lithium ion introduction, microwave sanding, spray drying, lithium ion export and the like. By coordinating microwave with mechanical force, the method can realize cyclic utilization of lithium salt solution, and greatly improve the yield of monolayer and few-layer graphene, and has the advantages of a simple process, safety and environmental protection, no chemical pollution and suitability for large-scale industrialized production. The graphene material prepared by the method has the advantages of high conductivity and thermal conductivity, and can be used as a conductive and heat conducting additive material and a negative electrode material of a lithium battery.

Description

technical field [0001] The invention belongs to the field of graphene preparation, in particular to a physical method for preparing graphene. Background technique [0002] Since Andre K. Geim (Andre K.Geim) of the University of Manchester in the United Kingdom prepared graphene materials in 2004, due to its unique structure and photoelectric properties, it has received widespread attention. Graphene is hailed as a rising "new star" in the field of materials science and condensed matter physics. Its many novel and unique properties and potential applications are attracting many scientific and technological workers. Graphene has a large specific surface area, excellent electrical and thermal conductivity and low thermal expansion coefficient. [0003] The current preparation methods of graphene mainly include: [0004] (1) Micromechanical exfoliation method, that is, directly exfoliate graphene flakes from larger crystals. For example, Chinese patent application CN101817516A...

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Problems solved by technology

[0004] (1) Micromechanical exfoliation method, that is, directly exfoliate graphene flakes from larger crystals. For example, Chinese patent application CN101817516A discloses a method for preparing graphene or graphene oxide by mechanical exfoliation, using solid particles and a liquid working medium ( or gas working medium) to obtain graphene or graphene oxide by mechanically peeling off the carbon material, and the carbon material is graphite powder, expanded graphite, expandable graphite or graphite oxide powder; this method is simple, but only Produces an extremely limited number of graphene sheets

[0005] (2) Ultra-high vacuum graphene epitaxial growth method, that is, epitaxial growth of graphene from the surface of silicon carbide or metal in an ultra-high vacuum and high temperature environment. Epitaxial growth on a silicon (SiC) substrate, this kind of graphene is forced to nucleate and grow controllably under the bombardment of electron beams, the number of layers of graphene can be controlled below 6 layers, and the average diameter of the generated area can reach the order of centimeters; The cost of this method is high and the structure of the small wafer limits its application

[0006] (3) Oxidation-reduction method, the whole process involves oxidizing graphite into graphite oxide, exfoliating graphite oxide to produce graphene oxide, and then reducing it to graphene through chemical or thermal reduction. For example, Chinese patent application CN103342904A discloses a titanate The method for preparing water-soluble graphene by coupling agent modification method, obtains graphene oxide by oxidation method, and connects titanate coupling agent while obtaining graphene, the obtained modified graphene can be stably dispersed in water, and Through the bridging effect of titanate coupling agent, the synthesis process of this method is cumbersome and the synthesized graphene is prone to defects

[0007] (4) Chemical Vapor Deposition (CVD), which uses carbon-containing compounds such as methane as a carbon source to prepare graphene through pyrolysis and growth on the surface of the substrate. For example, Chinese patent application CN103409728A discloses a chemical vapor deposition to prepare graphene The method comprises the following steps: washing the cobalt-nickel alloy substrate with an ethanol solution with a mass fraction of 75% for three times, and drying at 50° C. to 80° C.; putting the cobalt-nickel alloy substrate into a quartz furnace, and heating to 880°C-890°C, flow helium, the flow rate of helium is 50sccm; keep the temperature at 880°C-890°C and add ethylbenzene evenly into the quartz furnace; cool the quartz furnace to room temperature, take out the sample; ultrasonically treat the sample, The power of ultrasonic treatment is 800w, and the time is 60-90min to obtain graphene; this method can meet the requirements of large-scale preparation of high-quality graphene, but the cost is high and the process is complicated

[0008] (5) Solvent stripping method, that is, graphite powder is oxidized and stripped in a solvent, and then reduced to obtain graphene. The disadvantage of this method is that the yield is very low, which limits its large-scale preparation and application

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