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CN-121990566-A - Graphite material, preparation method thereof, electrochemical device and electronic equipment

CN121990566ACN 121990566 ACN121990566 ACN 121990566ACN-121990566-A

Abstract

The invention discloses a graphite material and a preparation method thereof, an electrochemical device and electronic equipment, wherein the graphite material meets the following conditions that (a) S is more than or equal to 8 and less than or equal to 13, S is a structural stability parameter, (b) L is more than or equal to 1.1 and less than or equal to 1.8, L is a secondary particle coefficient, (c) d is more than or equal to 1.0 and less than or equal to 1.2, and d is a particle size distribution width. The graphite material has both dynamic performance and wide temperature range adaptability.

Inventors

  • HOU SHUYAN

Assignees

  • 远景动力技术(江苏)有限公司
  • 远景睿泰动力技术(上海)有限公司

Dates

Publication Date
20260508
Application Date
20241107

Claims (10)

  1. 1. A graphite material, characterized in that it meets the following conditions: (a) S is more than or equal to 8 and less than or equal to 13, S is structural stability parameters; (b) L is more than or equal to 1.1 and less than or equal to 1.8 a secondary particle coefficient; (c) D is more than or equal to 1.0 and less than or equal to 1.2, d is width of particle size distribution.
  2. 2. The graphite material of claim 1, which meets one or more of the following conditions (a) - (c): (a) S is 10-12; (b) L is 1.4-1.7; (c) d is 1-1.12.
  3. 3. The graphite material of claim 1, which meets one or more of the following conditions (a) - (d): (a) The Dv90 particle size of the graphite material is 9-12 mu m; (b) The particle diameter of Dv10 of the graphite material is 2.5-3.6 mu m; (c) The Dv50 particle size of the graphite material is 5-8 mu m; (d) The porosity of the graphite material is 0.008-0.012cm 3 /g.
  4. 4. A method of preparing a graphite material according to any one of claims 1 to 3, comprising the steps of: the preparation method of the graphite intermediate comprises the steps of mixing a first graphite precursor and a second graphite precursor, wherein the first graphite precursor is obtained by carboxylation treatment of a graphite matrix, and the second graphite precursor is obtained by hydroxylation treatment of the graphite matrix.
  5. 5. The method of claim 4, wherein one or more of the following conditions (a) - (e) are satisfied: (a) The sphericity of the graphite intermediate is more than 0.87; (b) The Dv50 particle size of the graphite intermediate is 6-7.5 mu m; (c) The Dv10 particle size of the graphite intermediate is 1.8-4 mu m; (d) The Dv90 particle size of the graphite intermediate is 10-14 mu m; (e) The Dv50 particle size of the mixture is 5-9 μm.
  6. 6. The method of preparing a graphite material as claimed in claim 4, wherein one or more of the following conditions (a) to (c) are satisfied: (a) The mass content of the carbon source in the mixture is 0.6% -1%; (b) The mass content of the first graphite precursor in the mixture is 45% -49.9%; (c) The mass content of the second graphite precursor in the mixture is 45% -49.9%.
  7. 7. The method of claim 4, wherein one or more of the following conditions (a) - (d) are satisfied: (a) The treating agent used in the carboxylation treatment is acid liquor containing carboxyl; (b) The treating agent used in the hydroxylation treatment is alkali liquor; (c) The carbon source is one or more of sucrose, glucose and resin; (d) The coking value of the carbon source is below 60%.
  8. 8. The method of preparing a graphite material as claimed in claim 4, wherein one or more of the following conditions (a) to (f) are satisfied: (a) The carbonization time is 2-8h; (b) The preparation method of the graphite intermediate comprises the steps of mixing the first graphite precursor and the second graphite precursor, and then sequentially carrying out micro-shaping and grading treatment to obtain the graphite intermediate, wherein the micro-shaping time is 1-2.5h, and the grading treatment frequency is 30-70Hz; (c) The carbonization temperature is 600-900 ℃; (d) The preparation method of the mixture comprises the steps of mixing the graphite intermediate with a carbon source-containing solution and drying the mixture, wherein the mass fraction of the carbon source in the carbon source-containing solution is 0.5% -1.5%; (e) The graphite matrix meets the following conditions that La is less than or equal to 72 nm, lc is less than or equal to 15 nm and F is more than or equal to 15 mN; Wherein La is the lattice constant of graphite crystals in the graphite matrix at 110 faces, lc is the lattice constant of graphite crystals in the graphite matrix at 002 faces; (f) The graphite matrix is microcrystalline graphite.
  9. 9. An electrochemical device comprising a negative electrode sheet, wherein the negative electrode sheet comprises a negative electrode material layer and a negative electrode current collector, the negative electrode material layer comprising the graphite material of any one of claims 1-3 and 8.
  10. 10. An electronic device characterized in that it comprises the electrochemical device as claimed in claim 9.

Description

Graphite material, preparation method thereof, electrochemical device and electronic equipment Technical Field The invention relates to a graphite material, a preparation method thereof, an electrochemical device and electronic equipment. Background The microcrystalline graphite has low price of about 20-30% of the natural crystalline flake graphite with the same quality, but has extremely high impurity content, the impurity removal cost is about 2-3 times of that of the natural crystalline flake graphite with the same quality, and the cost is not dominant when comprehensively considered. The existing impurity removal technology such as CN104556022B is used for carrying out expansion treatment on microcrystalline graphite in an acid-base and intercalation heat treatment mode, and the dynamics can be improved, so that the compaction and first effect of the material can be greatly deteriorated, the specific surface area is obviously increased, the processing type of the material is obviously reduced, and the wide-temperature-range adaptability of the material is not facilitated. Therefore, there is a need for a graphite material that combines kinetic properties with wide temperature range adaptation properties. Disclosure of Invention The invention mainly aims to overcome the defect that a graphite material in the prior art cannot have both dynamic performance and wide-temperature-range adaptability, and provides a graphite material, a preparation method thereof, an electrochemical device and electronic equipment. The graphite material has both dynamic performance and wide temperature range adaptability. In a first aspect, the present invention provides a graphite material which satisfies the following conditions: (a) S is more than or equal to 8 and less than or equal to 13, S is structural stability parameters; (b) L is more than or equal to 1.1 and less than or equal to 1.8 a secondary particle coefficient; (c) D is more than or equal to 1.0 and less than or equal to 1.2, d is width of particle size distribution. In a second aspect, the present invention provides a method for preparing a graphite material as described above, comprising the steps of: the preparation method of the graphite intermediate comprises the steps of mixing a first graphite precursor and a second graphite precursor, wherein the first graphite precursor is obtained by carboxylation treatment of a graphite matrix, and the second graphite precursor is obtained by hydroxylation treatment of the graphite matrix. In a third aspect, the present invention provides an electrochemical device comprising a negative electrode sheet comprising a negative electrode material layer and a negative electrode current collector, the negative electrode material layer comprising a graphite material as described above. In a fourth aspect, the present invention provides an electronic device comprising an electrochemical apparatus as described above. The reagents and materials used in the present invention are commercially available. The invention has the positive progress effects that: According to the invention, the graphite precursor subjected to carboxylation treatment and hydroxylation treatment is mixed with a carbon source to prepare the graphite material with excellent performance, and the graphite material has excellent initial effect, cycle number and storage days, and also has excellent charge-discharge capacity, low-temperature capacity retention rate and quick charge time. Detailed Description Graphite material The graphite material provided in the first aspect of the present invention satisfies the following conditions: (a) S is more than or equal to 8 and less than or equal to 13, S is structural stability parameters; (b) L is more than or equal to 1.1 and less than or equal to 1.8 a secondary particle coefficient; (c) D is more than or equal to 1.0 and less than or equal to 1.2, d is width of particle size distribution. In the invention, the structural stability parameter S is a structural stability index of secondary particles of the graphite material (single particles are defined as 100.0). The specific test method comprises the steps of pressing a powder sample of a graphite material into a tablet by referring to national standard GB/T24533-2019, maintaining the pressure for 20S at standard pressure 2T before test, maintaining the pressure for 20S at 5T after 10min after pressure relief, starting formal operation after 10min after pressure relief interval, recording the powder pressure of 5T as P0, and then testing the powder sample of the graphite material at 5.5T, 6T, 6.5T, 4, 5+0.5n T and 4, wherein the recorded densities are P1, P2, P3, 4, pn and 4 respectively, and when Pn/Pn-1 is more than or equal to 1.05, the Pn is referred to as the particle structure failure density, and the structural stability parameter S=5+0.5n/5 is recorded. The specific testing method of the secondary particle coefficient L can be that powder samples of graph