CN116314775A - Modified natural graphite material and preparation method and application thereof - Google Patents

Modified natural graphite material and preparation method and application thereof Download PDF

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CN116314775A
CN116314775A CN202310297717.6A CN202310297717A CN116314775A CN 116314775 A CN116314775 A CN 116314775A CN 202310297717 A CN202310297717 A CN 202310297717A CN 116314775 A CN116314775 A CN 116314775A
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natural graphite
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graphite material
mixed powder
boric acid
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江志钦
徐坚
吕宗桓
仰韻霖
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Guangdong Kaijin New Energy Technology Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
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    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/20—Graphite
    • C01B32/21—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/20—Graphite
    • C01B32/21—After-treatment
    • C01B32/22—Intercalation
    • C01B32/225—Expansion; Exfoliation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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Abstract

The invention discloses a modified natural graphite material, a preparation method and application thereof, wherein the preparation method of the modified natural graphite material comprises the following steps: (1) Uniformly mixing natural graphite, boric acid and acetic acid to obtain a mixture; (2) Placing the mixture into a reaction kettle, heating, cooling, taking out, filtering, and drying to obtain a semi-finished product; (3) Uniformly mixing the semi-finished product with asphalt to obtain mixed powder; (4) And (3) placing the mixed powder in a nitrogen atmosphere for carbonization treatment, and sieving to obtain the boric acid modified natural graphite. According to the invention, boric acid is used as an intercalation agent to enter the surface of the graphite layer to form an interlayer compound, the interlayer spacing of the graphite layer is enlarged, the number of micropores is increased under the condition that the original graphite structure is not changed, the lithium ion migration rate is effectively improved, the natural graphite rate capability is improved, the boric acid is low in price, and the operation is simple and easy for large-scale production.

Description

Modified natural graphite material and preparation method and application thereof
Technical Field
The invention relates to the technical field of lithium ion battery cathode materials, in particular to a modified natural graphite material, a preparation method and application thereof.
Background
The graphite material is a main negative electrode material of the lithium ion battery because of the advantages of high specific capacity, high voltage platform, good safety performance and the like. Compared with artificial graphite, the natural graphite has the advantages of large reserve, low cost, high capacity, high compaction and the like, but the anisotropic structure characteristic of the natural graphite anode material limits the migration rate of lithium ions in a natural graphite structure and influences the exertion of the multiplying power performance of the natural graphite.
For the problem of poor rate capability of the natural graphite cathode, scientific researchers mainly improve the natural graphite in two aspects according to the working principle of a lithium battery: firstly, changing the structure of graphite microcrystal, adding the natural graphite cathode material with mesopores and macropores, so that the natural graphite cathode material has more active sites and spaces for lithium ion storage and diffusion, and is beneficial to rapid electronic conduction; secondly, the interlayer spacing of the natural graphite is enlarged, a microporous structure is prepared, the migration rate of lithium ions is enhanced, the adsorption and diffusion of interfacial lithium ions are promoted, the structural integrity of the natural graphite cathode in the charge and discharge process is maintained, the formation of a firm solid electrolyte interfacial film (SEI) is facilitated, the irreversible capacity is reduced, and the rate capability is improved.
Up to now, the problem that the natural graphite anode has poor multiplying power performance is still the main problem, and therefore, the boric acid modified natural graphite is developed to improve the multiplying power performance of the natural graphite.
Disclosure of Invention
In order to improve the multiplying power performance of natural graphite, the invention provides a preparation method of a modified natural graphite material, which comprises the following steps:
(1) Uniformly mixing natural graphite, boric acid and acetic acid to obtain a mixture;
(2) Placing the mixture into a reaction kettle, heating, cooling, taking out, filtering, and drying to obtain a semi-finished product;
(3) Uniformly mixing the semi-finished product with asphalt to obtain mixed powder;
(4) And (3) placing the mixed powder in a nitrogen atmosphere for carbonization treatment, and sieving to obtain the boric acid modified natural graphite.
Compared with the prior art, the preparation method of the modified natural graphite material uses boric acid as an intercalation agent and acetic acid as a solvent, and boron and boric acid enter the natural graphite in different forms in the reaction process, so that an interlayer compound is formed at the interlayer distance of the natural graphite, and the interlayer distance is enlarged. Then asphalt is used as a coating layer to solve the problem of flaking and scaling caused by interlayer spacing expansion and effectively improve the multiplying power performance of natural graphite. Therefore, boric acid is used as an intercalation agent to enter the surface of the graphite layer to form an interlayer compound, the interlayer spacing of the graphite layer is enlarged, the number of micropores is increased under the condition that the structure of the original graphite is not changed, the migration rate of lithium ions is effectively improved, the multiplying power performance of the natural graphite is improved, the price of the boric acid is low, and the operation is simple and the large-scale production is easy.
In some embodiments, in step (1), the natural graphite has a median particle size of 6-14 μm, and as an example, the natural graphite may have a median particle size of, but is not limited to, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm.
In some embodiments, in step (1), the mass ratio of the natural graphite, the boric acid, and the acetic acid is 5-20:1:5-20, and as an example, the mass ratio of the natural graphite, the boric acid, and the acetic acid is 10:1:20 or 15:1:20, but is not limited thereto.
In some embodiments, the natural graphite is spherical natural graphite or crystalline flake natural graphite, but is not limited thereto.
In some embodiments, in step (2), the heat treatment temperature is 150-180 ℃, and as an example, the heat treatment temperature may be, but is not limited to, 150 ℃, 160 ℃, 170 ℃, 175 ℃, 180 ℃.
In some embodiments, in step (2), the heat treatment time is 6-48 hours, which may be, by way of example and not limitation, 6 hours, 12 hours, 30 hours, 40 hours, 48 hours.
In some embodiments, in step (2), the reaction vessel is one of a hydrothermal vessel, a vertical vessel, a horizontal vessel, and the like.
In some embodiments, in step (3), the asphalt has a softening point of 150-250 ℃, which may be, but is not limited to, 150 ℃, 180 ℃, 210 ℃, 250 ℃, and 150-250 ℃ belonging to high temperature asphalt, and the use of high temperature asphalt is advantageous in improving the flaking problem, thereby improving the natural graphite rate capability.
In some embodiments, in step (3), the mass ratio of the semi-finished product to the asphalt is 100:3-15.
In some embodiments, in step (4), the carbonization treatment is performed at a temperature of 500-1400 ℃.
In some embodiments, in step (4), the carbonization treatment is divided into 2-stage treatments, the calcination temperature in the first stage being 500-700 ℃; the calcination temperature in the second stage is 800-1400 ℃. As an example, the calcination temperature in the first stage is 600 ℃, and the calcination temperature in the second stage is 1000 ℃, but not limited thereto.
In some embodiments, the sifting mesh is a 200-500 mesh, preferably a 325 mesh.
Correspondingly, the invention also provides a modified natural graphite material, which is prepared by adopting the preparation method of the modified natural graphite material, and the boric acid modified natural graphite has excellent multiplying power performance.
Correspondingly, the invention also provides the modified natural graphite material prepared by the preparation method of the modified natural graphite material or the application of the modified natural graphite material to the lithium ion battery negative electrode material, and the boric acid modified natural graphite is adopted as the lithium ion battery negative electrode material, so that the lithium ion migration rate can be effectively improved, and the natural graphite multiplying power performance can be improved.
Drawings
FIG. 1 is an SEM image of a modified natural graphite material prepared in example 1 of the present invention.
Detailed Description
The conception and the technical effects produced by the present invention will be clearly and completely described in conjunction with the embodiments below to fully understand the objects, features and effects of the present invention. It is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and that other embodiments obtained by those skilled in the art without inventive effort are within the scope of the present invention based on the embodiments of the present invention.
Example 1
A preparation method of a modified natural graphite material comprises the following steps:
(1) Uniformly stirring and mixing natural graphite (Dv50=11.7 mu m), boric Acid (AR) and acetic Acid (AR) according to a mass ratio of 5:1:20 to obtain a mixture;
(2) Placing the mixture into a reaction kettle, reacting at 170 ℃ for 12 hours, cooling, taking out, filtering, and drying to obtain a semi-finished product;
(3) Uniformly mixing the semi-finished product and asphalt (with the softening point of 250 ℃) according to the mass ratio of 100:3 to obtain mixed powder;
(4) And (3) placing the mixed powder in a box furnace, heating the mixed powder from room temperature to 600 ℃ under the nitrogen atmosphere, continuously heating the mixed powder for 3 to 1000 ℃ after calcining for 2 hours, naturally cooling the mixed powder to room temperature after calcining for 3 hours, and sieving the powder by a 325-mesh sieve to obtain the boric acid modified natural graphite.
Example 2
A preparation method of a modified natural graphite material comprises the following steps:
(1) Uniformly stirring and mixing natural graphite (Dv50=11.7 mu m), boric Acid (AR) and acetic Acid (AR) according to a mass ratio of 5:1:20 to obtain a mixture;
(2) Placing the mixture into a reaction kettle, reacting at 170 ℃ for 12 hours, cooling, taking out, filtering, and drying to obtain a semi-finished product;
(3) Uniformly mixing the semi-finished product and asphalt (with the softening point of 250 ℃) according to the mass ratio of 100:3 to obtain mixed powder;
(4) And (3) placing the mixed powder in a box furnace, heating the mixed powder from room temperature to 600 ℃ under the nitrogen atmosphere, continuously heating the mixed powder for 3 to 1200 ℃ after calcining for 2 hours, naturally cooling the mixed powder to room temperature after calcining for 3 hours, and sieving the powder by a 325-mesh sieve to obtain the boric acid modified natural graphite.
Example 3
A preparation method of a modified natural graphite material comprises the following steps:
(1) Uniformly stirring and mixing natural graphite (Dv50=11.7 mu m), boric Acid (AR) and acetic Acid (AR) according to a mass ratio of 10:1:20 to obtain a mixture;
(2) Placing the mixture into a reaction kettle, reacting at 170 ℃ for 12 hours, cooling, taking out, filtering, and drying to obtain a semi-finished product;
(3) Uniformly mixing the semi-finished product and asphalt (with the softening point of 250 ℃) according to the mass ratio of 100:3 to obtain mixed powder;
(4) And (3) placing the mixed powder in a box furnace, heating the mixed powder from room temperature to 600 ℃ under the nitrogen atmosphere, continuously heating the mixed powder for 3 to 1000 ℃ after calcining for 2 hours, naturally cooling the mixed powder to room temperature after calcining for 3 hours, and sieving the powder by a 325-mesh sieve to obtain the boric acid modified natural graphite.
Example 4
A preparation method of a modified natural graphite material comprises the following steps:
(1) Uniformly stirring and mixing natural graphite (Dv50=11.7 mu m), boric Acid (AR) and acetic Acid (AR) according to a mass ratio of 10:1:20 to obtain a mixture;
(2) Placing the mixture into a reaction kettle, reacting at 170 ℃ for 12 hours, cooling, taking out, filtering, and drying to obtain a semi-finished product;
(3) Uniformly mixing the semi-finished product and asphalt (with the softening point of 250 ℃) according to the mass ratio of 100:3 to obtain mixed powder;
(4) And (3) placing the mixed powder in a box furnace, heating the mixed powder from room temperature to 600 ℃ under the nitrogen atmosphere, continuously heating the mixed powder for 3 to 1200 ℃ after calcining for 2 hours, naturally cooling the mixed powder to room temperature after calcining for 3 hours, and sieving the powder by a 325-mesh sieve to obtain the boric acid modified natural graphite.
Example 5
A preparation method of a modified natural graphite material comprises the following steps:
(1) Uniformly stirring and mixing natural graphite (Dv50=11.7 mu m), boric Acid (AR) and acetic Acid (AR) according to a mass ratio of 15:1:20 to obtain a mixture;
(2) Placing the mixture into a reaction kettle, reacting at 170 ℃ for 12 hours, cooling, taking out, filtering, and drying to obtain a semi-finished product;
(3) Uniformly mixing the semi-finished product and asphalt (with the softening point of 250 ℃) according to the mass ratio of 100:3 to obtain mixed powder;
(4) And (3) placing the mixed powder in a box furnace, heating the mixed powder from room temperature to 600 ℃ under the nitrogen atmosphere, continuously heating the mixed powder for 3 to 1000 ℃ after calcining for 2 hours, naturally cooling the mixed powder to room temperature after calcining for 3 hours, and sieving the powder by a 325-mesh sieve to obtain the boric acid modified natural graphite.
Example 6
A preparation method of a modified natural graphite material comprises the following steps:
(1) Uniformly stirring and mixing natural graphite (Dv50=11.7 mu m), boric Acid (AR) and acetic Acid (AR) according to a mass ratio of 15:1:20 to obtain a mixture;
(2) Placing the mixture into a reaction kettle, reacting at 170 ℃ for 12 hours, cooling, taking out, filtering, and drying to obtain a semi-finished product;
(3) Uniformly mixing the semi-finished product and asphalt (with the softening point of 250 ℃) according to the mass ratio of 100:3 to obtain mixed powder;
(4) And (3) placing the mixed powder in a box furnace, heating the mixed powder from room temperature to 600 ℃ under the nitrogen atmosphere, continuously heating the mixed powder for 3 to 1200 ℃ after calcining for 2 hours, naturally cooling the mixed powder to room temperature after calcining for 3 hours, and sieving the powder by a 325-mesh sieve to obtain the boric acid modified natural graphite.
Example 7
A preparation method of a modified natural graphite material comprises the following steps:
(1) Uniformly stirring and mixing natural graphite (Dv50=11.7 mu m), boric Acid (AR) and acetic Acid (AR) according to a mass ratio of 20:1:20 to obtain a mixture;
(2) Placing the mixture into a reaction kettle, reacting at 170 ℃ for 12 hours, cooling, taking out, filtering, and drying to obtain a semi-finished product;
(3) Uniformly mixing the semi-finished product and asphalt (with the softening point of 250 ℃) according to the mass ratio of 100:3 to obtain mixed powder;
(4) And (3) placing the mixed powder in a box furnace, heating the mixed powder from room temperature to 600 ℃ under the nitrogen atmosphere, continuously heating the mixed powder for 3 to 1000 ℃ after calcining for 2 hours, naturally cooling the mixed powder to room temperature after calcining for 3 hours, and sieving the powder by a 325-mesh sieve to obtain the boric acid modified natural graphite.
Example 8
A preparation method of a modified natural graphite material comprises the following steps:
(1) Uniformly stirring and mixing natural graphite (Dv50=11.7 mu m), boric Acid (AR) and acetic Acid (AR) according to a mass ratio of 20:1:20 to obtain a mixture;
(2) Placing the mixture into a reaction kettle, reacting at 170 ℃ for 12 hours, cooling, taking out, filtering, and drying to obtain a semi-finished product;
(3) Uniformly mixing the semi-finished product and asphalt (with the softening point of 250 ℃) according to the mass ratio of 100:3 to obtain mixed powder;
(4) And (3) placing the mixed powder in a box furnace, heating the mixed powder from room temperature to 600 ℃ under the nitrogen atmosphere, continuously heating the mixed powder for 3 to 1200 ℃ after calcining for 2 hours, naturally cooling the mixed powder to room temperature after calcining for 3 hours, and sieving the powder by a 325-mesh sieve to obtain the boric acid modified natural graphite.
Example 9
A preparation method of a modified natural graphite material comprises the following steps:
(1) Uniformly stirring and mixing natural graphite (Dv50=8μm), boric Acid (AR) and acetic Acid (AR) according to a mass ratio of 10:1:10 to obtain a mixture;
(2) Placing the mixture into a reaction kettle, reacting at 160 ℃ for 18 hours, cooling, taking out, filtering, and drying to obtain a semi-finished product;
(3) Uniformly mixing the semi-finished product with asphalt (the softening point is 200 ℃) according to the mass ratio of 100:6 to obtain mixed powder;
(4) And (3) placing the mixed powder in a box furnace, heating the mixed powder from room temperature to 700 ℃ under the nitrogen atmosphere, continuously heating the mixed powder for 3 to 1400 ℃ after calcining for 2 hours, naturally cooling the mixed powder to room temperature after calcining for 3 hours, and sieving the powder with a 325-mesh sieve to obtain the boric acid modified natural graphite.
Example 10
A preparation method of a modified natural graphite material comprises the following steps:
(1) Uniformly stirring and mixing natural graphite (Dv50=10μm), boric Acid (AR) and acetic Acid (AR) according to a mass ratio of 20:1:5 to obtain a mixture;
(2) Placing the mixture into a reaction kettle, reacting at 150 ℃ for 24 hours, cooling, taking out, filtering, and drying to obtain a semi-finished product;
(3) Uniformly mixing the semi-finished product and asphalt (with a softening point of 150 ℃) according to a mass ratio of 100:10 to obtain mixed powder;
(4) And (3) placing the mixed powder in a box furnace, heating the mixed powder from room temperature to 600 ℃ under the nitrogen atmosphere, continuously heating the mixed powder for 3 to 1000 ℃ after calcining for 2 hours, naturally cooling the mixed powder to room temperature after calcining for 5 hours, and sieving the powder by a 325-mesh sieve to obtain the boric acid modified natural graphite.
Comparative example 1
A preparation method of a modified natural graphite material comprises the following steps:
(1) Uniformly mixing natural graphite (Dv50=11.7 μm) and asphalt (the softening point is 250 ℃) according to the mass ratio of 100:3 to obtain mixed powder;
(2) And (3) placing the mixed powder in a box furnace, heating the mixed powder from room temperature to 600 ℃ under the nitrogen atmosphere, continuously heating the mixed powder for 3 to 1000 ℃ after calcining for 2 hours, naturally cooling the mixed powder to room temperature after calcining for 3 hours, and sieving the powder by a 325-mesh sieve to obtain the modified natural graphite.
Comparative example 2
A preparation method of a modified natural graphite material comprises the following steps:
(1) Uniformly mixing natural graphite (Dv50=11.7 μm) and asphalt (the softening point is 250 ℃) according to the mass ratio of 100:3 to obtain mixed powder;
(2) And (3) placing the mixed powder in a box furnace, heating the mixed powder from room temperature to 600 ℃ under the nitrogen atmosphere, continuously heating the mixed powder for 3 to 1200 ℃ after calcining for 2 hours, naturally cooling the mixed powder to room temperature after calcining for 3 hours, and sieving the powder with a 325-mesh sieve to obtain the modified natural graphite.
FIG. 1 is an SEM image of a modified natural graphite material produced in example 1 of the present invention. As can be seen from fig. 1, there is much smaller particle size graphite, which is formed by the fact that boron atoms enter the graphite to enlarge interlayer spacing and at the same time, some scales fall off and are coated, which means that boron and boric acid successfully enter the graphite at high temperature.
The boric acid-modified natural graphite materials prepared in examples 1 to 10 and the graphite materials in comparative examples 1 to 2 were subjected to a rate charge and discharge test by a half-cell test method, and the results are shown in table 1. The testing method comprises the following steps: uniformly coating graphite material, N-methyl pyrrolidone solution of polyvinylidene fluoride with the concentration of 6% and SP on copper foil after mixing according to the mass ratio of 92:4:4, and then carrying out vacuum drying treatment on the pole piece at 105 ℃ for 24 hours; assembling the button cell in a glove box, and the electrolyte: the electrolyte is LiPF6, the concentration is 1M, the solvent is composed of dimethyl carbonate, ethylene carbonate and ethylmethyl carbonate in a volume ratio of 1:1:1, the counter electrode is a lithium sheet, and the whole test is completed on an Arbin electrochemical detection system in America.
Table 1 test results
Figure BDA0004143741680000101
As can be seen from the results of Table 1, the modified natural graphite showed a decrease in the capacity retention rate of the samples with increasing the rates of the examples 1 to 10 compared with the comparative examples 1 to 2, and the rate of decay of the sample capacity of the examples 1 to 10 was significantly lower than that of the comparative examples 1 to 2, as the rates of the modified natural graphite were measured at 0.1C, 1C, 2C, 3C, and 5C, respectively. It is possible that the boric acid modified sample forms a graphite interlayer compound with a larger interlayer spacing, thereby reducing Li during charge and discharge + The resistance of intercalation and deintercalation promotes the migration rate of lithium ions, forms a stable SEI film, prevents the co-intercalation of electrolyte solvent molecules, and promotes the rapid charge and discharge performance under large current.
As can be seen from Table 1, the ratio of natural graphite to boric acid to acetic acid is 20:1:20, and the capacity retention rate of the modified sample at 5C multiplying power can reach 83% at 1000 ℃ at the calcining temperature, so that the multiplying power performance of the modified sample is improved by 17.8% compared with that of the conventional natural graphite.
With continued reference to Table 1, the modified natural graphite materials of examples 1 to 10 have lower initial efficiencies than comparative examples 1-2.This is probably due to the fact that the radius of boron atoms is larger than that of carbon atoms, graphite expands while entering the graphite structure to expand the interlayer spacing, part of outer layer flake graphite falls off, the specific surface is increased, and more Li is consumed for generating the SEI film + 。
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the present invention can be modified or substituted without departing from the spirit and scope of the technical solution of the present invention.

Claims (10)

1. The preparation method of the modified natural graphite material is characterized by comprising the following steps:
(1) Uniformly mixing natural graphite, boric acid and acetic acid to obtain a mixture;
(2) Placing the mixture into a reaction kettle, heating, cooling, taking out, filtering, and drying to obtain a semi-finished product;
(3) Uniformly mixing the semi-finished product with asphalt to obtain mixed powder;
(4) And (3) placing the mixed powder in a nitrogen atmosphere for carbonization treatment, and sieving to obtain the boric acid modified natural graphite.
2. The method for producing a modified natural graphite material according to claim 1, wherein in the step (1), the natural graphite has a median particle diameter of 6 to 14 μm.
3. The method for producing a modified natural graphite material according to claim 1, wherein in the step (1), the mass ratio of the natural graphite, the boric acid, and the acetic acid is 5-20:1:5-20.
4. The method for producing a modified natural graphite material as claimed in claim 1, wherein in the step (2), the heat treatment temperature is 150 to 180 ℃.
5. The method for producing a modified natural graphite material as claimed in claim 1, wherein in the step (3), the softening point of the pitch is 150 to 250 ℃.
6. The method of producing a modified natural graphite material according to claim 1, wherein in the step (3), the mass ratio of the semi-finished product to the pitch is 100:3-15.
7. The method for producing a modified natural graphite material as claimed in claim 1, wherein in the step (4), the carbonization treatment is carried out at a temperature of 500 to 1400 ℃.
8. The method for producing a modified natural graphite material according to claim 7, wherein in the step (4), the carbonization treatment is divided into 2-stage treatment, and the calcination temperature in the first stage is 500 to 700 ℃; the calcination temperature in the second stage is 800-1400 ℃.
9. A modified natural graphite material, characterized by being produced according to the production method of the modified natural graphite material as claimed in any one of claims 1 to 8.
10. A modified natural graphite material produced by the production method of a modified natural graphite material according to any one of claims 1 to 8 or a modified natural graphite material according to claim 9 for use in a negative electrode material of a lithium ion battery.
CN202310297717.6A 2023-03-24 2023-03-24 Modified natural graphite material and preparation method and application thereof Pending CN116314775A (en)

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