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CN-121990554-A - Modified coal-based hard carbon and preparation method thereof

CN121990554ACN 121990554 ACN121990554 ACN 121990554ACN-121990554-A

Abstract

The invention relates to the field of battery materials, in particular to a modified coal-based hard carbon and a preparation method thereof; according to the method, etching of a sodium chloride template is firstly carried out, then a chitosan derived carbon coating is carried out, and then dry ice grinding is carried out, so that the coal-based hard carbon material with large interlayer spacing, surface etching and abundant defects is finally obtained. Has smaller particle size, higher oxygen content and defect concentration than conventional hard carbon. The modified coal-based hard carbon disclosed by the invention controls the microcrystalline structure through etching of the salt template, so that the interlayer spacing is improved. The chitosan-derived carbon coating optimizes the surface and defect structure. The method for combining salt template etching and chitosan derived carbon coating is used for preparing coal-based hard carbon with controllable pore structure, so that accurate conversion from coal to hard carbon is realized. Further dry ice milling has a smaller particle size and mitigates particle agglomeration. The defect concentration is further improved by utilizing the physicochemical synergistic effect, and the etching effect of the surface of the hard carbon material is promoted.

Inventors

  • JIANG JINLIN
  • CAI XIANYU
  • ZHONG YIHUA
  • LI ENYU
  • LIU XINGSHUANG
  • QIU XINGQI
  • WANG JUNHONG
  • ZHAO YUNZHU

Assignees

  • 双登集团股份有限公司
  • 江苏双登富朗特新能源有限公司

Dates

Publication Date
20260508
Application Date
20251231

Claims (10)

  1. 1. The preparation method of the modified coal-based hard carbon is characterized by comprising the following steps: s1, mixing pulverized coal and sodium chloride, and then performing heating treatment to obtain a pre-carbonized product; S2, mixing the pre-carbonized product with chitosan, and then sequentially performing first ball milling treatment, normal-pressure heating treatment and second ball milling treatment to obtain the modified coal-based hard carbon.
  2. 2. The method according to claim 1, wherein in the step S1, the mass ratio of the pulverized coal to the sodium chloride is 1 (2-5).
  3. 3. The method according to claim 1, wherein in the step S1, the heating treatment atmosphere comprises at least one of nitrogen, helium and argon, the heating temperature is 600-800 ℃, the heating pressure is 0.2-0.5Mpa, and the heating time is 2-4h.
  4. 4. The method according to claim 1, wherein in step S2, the mass ratio of the pre-carbonized product to the chitosan is (1-4): 1.
  5. 5. The method according to claim 1, wherein in step S2, the first ball milling treatment comprises placing the mixture of the pre-carbonized product and the chitosan in a planetary ball mill and adding dry ice for milling.
  6. 6. The method according to claim 5, wherein the mass ratio of the mixture to the dry ice is (1-3): 1, and the mass ratio of the pellets is (20-30): 1.
  7. 7. The method according to claim 1, wherein in the step S2, the atmosphere for the normal pressure heating treatment comprises at least one of nitrogen, helium and argon, the heating temperature is 900-1500 ℃, and the heating time is 3-8 hours.
  8. 8. The method according to claim 1, wherein in the step S2, the second ball milling treatment comprises placing the material subjected to the normal pressure heating treatment in a planetary ball mill, and adding dry ice for grinding.
  9. 9. The method according to claim 8, wherein the mass ratio of the material subjected to the atmospheric heating treatment to the dry ice is (1-3) 1, and the mass ratio of the pellets is (20-30) 1.
  10. 10. A modified coal-based hard carbon produced by the production method according to any one of claims 1 to 9.

Description

Modified coal-based hard carbon and preparation method thereof Technical Field The invention relates to the field of battery materials, in particular to a modified coal-based hard carbon and a preparation method thereof. Background The sodium ion battery has the advantages of cost compared with the lithium ion battery after large-scale production due to the wide distribution of sodium resources and abundant resources. And the sodium ion battery has high safety and superior low-temperature capability, and is gradually applied to a large-scale energy storage system and a north vehicle start-stop battery. The design and construction of high-performance low-cost electrode materials is critical to the popularization of sodium ion batteries. Hard carbon is used as a main sodium ion battery material, wherein coal can be used as a precursor for preparing hard carbon with excellent quality due to high carbon content and low cost. The coal-based production process has the advantages of simple route, rich coal resources in China and low price, and is a production route with large-scale potential. However, the structure of coal is difficult to regulate and control, and the composition is complex, so that the initial coulombic efficiency is low, and the rate performance is poor. It is desirable to modify it to produce hard carbon with high capacity and high initial coulombic efficiency. Disclosure of Invention The invention aims at overcoming the defects in the prior art and provides a modified coal-based hard carbon and a preparation method thereof. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the first aspect of the invention provides a method for preparing modified coal-based hard carbon, comprising the following steps: s1, mixing pulverized coal and sodium chloride, and then performing heating treatment to obtain a pre-carbonized product; S2, mixing the pre-carbonized product with chitosan, and then sequentially performing first ball milling treatment, normal-pressure heating treatment and second ball milling treatment to obtain the modified coal-based hard carbon. Preferably, in step S1, the mass ratio of the pulverized coal to the sodium chloride is 1 (2-5). Preferably, in the step S1, the heating treatment atmosphere comprises at least one of nitrogen, helium and argon, the heating temperature is 600-800 ℃, the heating pressure is 0.2-0.5Mpa, and the heating time is 2-4h. Preferably, step S1 further comprises washing the pre-carbonized product with deionized water. Preferably, in step S2, the mass ratio of the pre-carbonized product to the chitosan is (1-4): 1. Preferably, in the step S2, the first ball milling treatment comprises the steps of placing the mixture of the pre-carbonized product and the chitosan in a planetary ball mill, and adding dry ice for grinding. More preferably, the mass ratio of the mixture to the dry ice is (1-3): 1, and the mass ratio of the pellets is (20-30): 1. Preferably, in the step S2, the atmosphere of the normal pressure heating treatment comprises at least one of nitrogen, helium and argon, the heating temperature is 900-1500 ℃, and the heating time is 3-8h. Preferably, in the step S2, the second ball milling treatment comprises the steps of placing the material subjected to the normal-pressure heating treatment in a planetary ball mill, and adding dry ice for grinding. More preferably, the mass ratio of the material subjected to the normal pressure heating treatment to the dry ice is (1-3) to 1, and the mass ratio of the ball material is (20-30) to 1. The second aspect of the invention provides the modified coal-based hard carbon prepared by the preparation method. Compared with the prior art, the invention has the following technical effects: According to the method, etching of a sodium chloride template is firstly carried out, then a chitosan derived carbon coating is carried out, and then dry ice grinding is carried out, so that the coal-based hard carbon material with large interlayer spacing, surface etching and abundant defects is finally obtained. Has smaller particle size, higher oxygen content and defect concentration than conventional hard carbon. The modified coal-based hard carbon disclosed by the invention controls the microcrystalline structure through etching of the salt template, so that the interlayer spacing is improved. The chitosan-derived carbon coating optimizes the surface and defect structure. The method for combining salt template etching and chitosan derived carbon coating is used for preparing coal-based hard carbon with controllable pore structure, so that accurate conversion from coal to hard carbon is realized. Further dry ice milling has a smaller particle size and mitigates particle agglomeration. The defect concentration is further improved by utilizing the physicochemical synergistic effect, and the etching effect of the surface of the hard carbon material is promoted. Detailed Description T