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CN-117125703-B - Method for rapidly preparing graphene, graphene powder and graphene aqueous slurry

CN117125703BCN 117125703 BCN117125703 BCN 117125703BCN-117125703-B

Abstract

The invention discloses a method for rapidly preparing graphene, graphene powder and graphene aqueous slurry, which belong to the field of inorganic nano materials, wherein the method for rapidly preparing graphene comprises the following steps of performing high-temperature treatment on a graphite raw material to obtain a graphite material with more uniformly arranged carbon atoms; the preparation method comprises the steps of pretreatment, namely, carrying out rapid pretreatment on a graphite material under a concentrated acid system to obtain a graphite interlayer compound, and carrying out rapid electrochemical stripping, namely, soaking the pretreated graphite material into electrolyte at a certain speed, electrolyzing until obvious graphite expansion bodies appear, and carrying out auxiliary stripping to obtain graphene powder. According to the invention, the graphite raw material is subjected to high-temperature treatment, so that originally distributed disordered carbon atoms are orderly arranged, and a Graphite Interlayer Compound (GICs) which does not damage a graphite lamellar structure is formed between graphene layers under the electrochemical action of a concentrated acid system, so that the subsequent electrochemical stripping speed is higher, the graphene lamellar layers are more uniform, and the graphene quality is higher.

Inventors

  • CHEN WENMIAO
  • CHEN JIE
  • LI MENGYU
  • PEI XIAODONG

Assignees

  • 中钢集团南京新材料研究院有限公司

Dates

Publication Date
20260512
Application Date
20220519

Claims (8)

  1. 1. A method for rapidly preparing graphene, comprising the steps of: high temperature treatment, namely carrying out high temperature treatment on the graphite raw material to obtain a graphite material with more uniformly arranged carbon atoms, wherein the treatment temperature of the high temperature treatment is 1500-3000 ℃ and the treatment time is 10-48h; Pretreatment, namely rapidly pretreating graphite materials in a concentrated acid system, wherein the pretreatment voltage is 0.5V-6V, and the pretreatment time is 1-10min, so as to obtain a graphite interlayer compound; the method comprises the steps of fast electrochemical stripping, namely immersing the pretreated graphite material into electrolyte at a certain speed, electrolyzing until obvious graphite expansion bodies appear, and carrying out auxiliary stripping to obtain graphene powder; the auxiliary stripping comprises electrochemical stripping by electrolysis and simultaneously cooling circulation and ultrasonic assistance, wherein the temperature of the cooling circulation is-20 ℃ to 0 ℃.
  2. 2. The method of claim 1, wherein the concentrated acid is selected from one or more of concentrated sulfuric acid, concentrated nitric acid, concentrated hydrochloric acid, and concentrated phosphoric acid.
  3. 3. The method of claim 1, wherein the graphite material infiltrates at a rate of 0.2-2mm/s in the rapid electrochemical stripping step.
  4. 4. The method of claim 1, wherein the rapid electrochemical stripping is at a voltage of 4V-20V for a period of 2-8min.
  5. 5. The method of claim 1, wherein the electrolyte for rapid electrochemical stripping is selected from one or more of sulfate solution, persulfate solution, phosphate solution, perchlorate solution, and ammonium salt solution, and the concentration of the electrolyte is 0.05M to 1M.
  6. 6. The method of claim 1, wherein the ultrasound has a frequency of 20-60KHz and a power of 50-1000W.
  7. 7. The graphene powder is characterized in that the graphene powder is prepared by the method of any one of claims 1-6, the thickness of the graphene powder is 2-5nm, and the conductivity is (0.8-10.0) multiplied by 10 4 S/m.
  8. 8. An aqueous graphene slurry obtained by homogeneously dispersing the graphene powder according to claim 7 in water.

Description

Method for rapidly preparing graphene, graphene powder and graphene aqueous slurry Technical Field The invention belongs to the field of inorganic nano materials, and particularly relates to a method for rapidly preparing graphene, graphene powder and graphene aqueous slurry. Background The existing preparation method for preparing the graphene mainly comprises a mechanical physical stripping method, including an adhesive tape tearing method and an ultrasonic stripping method. The ultrasonic stripping method utilizes the interaction of the surface tension of the solvent and the graphite material to achieve the stripping effect. However, the graphene sheets prepared by the method are thicker and have nonuniform quality. In addition, since most solvents are organic solvents, environmental pollution exists, and the subsequent treatment is troublesome. The other type is a chemical method, and graphene is obtained by chemical reaction, and the chemical reaction mainly comprises a CVD method and a hummers method. The graphene prepared by the CVD method has the advantages of adjustable layer number and high quality. However, the method is high in cost, long in time consumption and complex in graphene transfer process. The Hummers method for preparing graphene oxide has rich functional groups, long reaction time, high operation risk, high environmental pollution and high cost. Patent CN105417537a discloses a method for rapidly peeling graphene by taking graphite blocks as raw materials by utilizing the synergistic effect of ultrasound and an electric field. And then further crushing and separating, and finally obtaining the graphene powder through manual screening. However, the quality of the graphene powder is not uniform, and the size of the graphene sheet layer can be influenced by secondary ultrasonic treatment after manual screening. Patent CN103072980B discloses that intercalation of a solid oxidant and a liquid oxidant is used to obtain a graphite interlayer compound, a water bath reaction is performed in a nitrate solution, and ultrasonic cavitation is used to obtain a graphene dispersion in an anionic surfactant. The residual anionic surfactant in the obtained graphene powder affects the conductivity of the graphene powder. Patent CN113666366a adopts molybdate water solution as electrolyte, and 76% of graphene sheets not exceeding five layers are obtained through centrifugal screening. The obtained graphene aqueous solution has certain dispersibility, the quality of the sheet layers is not uniform, and thicker graphene can be obviously seen in the picture. Disclosure of Invention The invention aims to solve the technical problems of long consumption time for preparing graphene in the prior art, nonuniform quality of prepared graphene sheets and thicker thickness, and provides a preparation method of graphene, graphene powder and graphene aqueous slurry. The first aspect of the invention provides a method for rapidly preparing graphene, comprising the following steps: High temperature treatment, namely performing high temperature treatment on the graphite raw material to obtain a graphite material with more uniformly arranged carbon atoms; Pretreatment, namely rapidly pretreating the graphite material in a concentrated acid system to obtain Graphite Intercalation Compounds (GICs); And (3) quick electrochemical stripping, namely soaking the pretreated graphite material into electrolyte at a certain speed, electrolyzing until obvious graphite expansion bodies appear, and carrying out auxiliary stripping to obtain graphene powder. In some embodiments, the high temperature treatment is performed at a treatment temperature of 1500 to 3000 ℃ for a treatment time of 10 to 48 hours. In some embodiments, the concentrated acid comprises one or more of concentrated sulfuric acid, concentrated nitric acid, concentrated hydrochloric acid, and concentrated phosphoric acid. In some embodiments, the pre-treatment is performed at a voltage of 0.5V to 6V for a period of 1 to 10 minutes. In some embodiments, the speed of infiltration of the graphite material in the rapid electrochemical stripping step is from 0.2 to 2mm/s; and/or the voltage of the rapid electrochemical stripping is 4V-20V, and the time is 2-8min. In some embodiments, the fast electrochemical stripping electrolyte comprises one or more of a sulfate solution, a persulfate solution, a phosphate solution, a perchlorate solution, and an ammonium salt solution, and the concentration of the electrolyte is 0.05M to 1M. In some embodiments, the assisted stripping comprises electrochemical stripping with simultaneous cooling cycle and ultrasound assistance. In some embodiments, the temperature of the cooling cycle is from-20 ℃ to 0 ℃; and/or the frequency of the ultrasonic wave is 20-60KHz, and the power of the ultrasonic wave is 50-1000W. The second aspect of the invention provides graphene powder, which is prepared by the method, wherein the thickness of graphene is