CN112117450A - Preparation method of graphite cathode - Google Patents
Preparation method of graphite cathode Download PDFInfo
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- CN112117450A CN112117450A CN202011062378.6A CN202011062378A CN112117450A CN 112117450 A CN112117450 A CN 112117450A CN 202011062378 A CN202011062378 A CN 202011062378A CN 112117450 A CN112117450 A CN 112117450A
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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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- 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
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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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
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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
- H01M4/362—Composites
- H01M4/366—Composites as layered products
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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
- H01M2004/021—Physical characteristics, e.g. porosity, surface area
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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
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
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- 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
Abstract
The invention provides a preparation method of a graphite cathode, which comprises the steps of providing a graphite material, enabling the graphite material to pass through a first screen, collecting the material on the first screen as a first graphite material, collecting the material under the first screen and passing the material through a second screen, collecting the material on the second screen as a second graphite material, collecting the material under the second screen and passing the material through a third screen, collecting the material on the third screen as a third graphite material, collecting the material under the third screen as a fourth graphite material, mixing the first graphite material and the fourth graphite material according to a preset mass ratio, placing the mixture in a ball mill for high-speed ball milling, enabling the fourth graphite material to coat the first graphite material to form a coating material, pulping the coating material to obtain cathode active slurry, coating the cathode active slurry on the surface of a current collector, drying, and obtaining the graphite cathode. The graphite cathode has high rate performance and cycle life.
Description
Technical Field
The invention relates to a preparation method of a graphite cathode.
Background
The negative electrode material of the lithium ion battery comprises graphite, alloy, metal oxide and other materials, wherein the graphite is one of the most common negative electrode materials of the lithium ion battery as the negative electrode material with the lowest cost, the most extensive source and stable performance, and how to further improve the cycle life and the rate capability of the graphite negative electrode belongs to one of the research targets for the research and development of the graphite negative electrode.
Disclosure of Invention
The invention provides a preparation method of a graphite cathode, which comprises the steps of providing a graphite material, enabling the graphite material to pass through a first screen, collecting the material on the first screen as a first graphite material, collecting the material under the first screen and passing the material through a second screen, collecting the material on the second screen as a second graphite material, collecting the material under the second screen and passing the material through a third screen, collecting the material on the third screen as a third graphite material, collecting the material under the third screen as a fourth graphite material, mixing the first graphite material and the fourth graphite material according to a preset mass ratio, placing the mixture in a ball mill for high-speed ball milling, enabling the fourth graphite material to coat the first graphite material to form a coating material, pulping the coating material, mixing the coating material with slurry made of the second graphite material and slurry made of the third graphite material according to the preset mass ratio, and obtaining negative active slurry, then coating the negative active slurry on the surface of the current collector, and drying to obtain the graphite negative electrode. The graphite cathode has high rate performance and cycle life.
The specific scheme is as follows:
a method of making a graphite anode, the method comprising:
1) providing a graphite material having an average particle size, D50, of 1.9-2.1 microns, D10 of 0.5-0.7 microns, and D90 of 3.4-3.6 microns;
2) passing a graphite material through a first screen, wherein the aperture of the first screen is 3.2-3.4 microns, and collecting the material on the first screen as a first graphite material;
3) collecting the material under the first screen and passing it through a second screen, the second screen having a pore size of 2.2-2.4 microns, and collecting the material on the second screen as a second graphite material;
4) collecting the material under the second screen and passing through a third screen, wherein the aperture of the third screen is 0.6-0.8 micron, and collecting the material on the third screen as a third graphite material;
5) collecting the material under the third screen mesh as a fourth graphite material;
6) mixing the first graphite material and the fourth graphite material according to the mass ratio of 100:25-28, and placing the mixture in a ball mill for high-speed ball milling to enable the fourth graphite material to coat the first graphite material to form a coating material;
7) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the coating material and the conductive material, and uniformly stirring to obtain a first slurry;
8) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, adding the second graphite material and the conductive material, and uniformly stirring to obtain a second slurry;
9) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, adding the third graphite material and the conductive material, and uniformly stirring to obtain a third slurry;
10) mixing the first slurry, the second slurry and the third slurry to obtain negative active slurry, wherein the mass ratio of the coating materials: a second graphite material: a third graphite material 24:34:42-26:36: 38;
11) and coating the negative active slurry on the surface of the current collector, and drying to obtain the graphite negative electrode.
Furthermore, in the high-speed ball milling, the ball-material ratio is 2.5:1, the rotating speed is 180-.
Further, the graphite material is natural graphite.
Further, the graphite material had an average particle size of D50 of 2.0 microns, D10 of 0.6 microns, and D90 of 3.5 microns.
Further, the first screen has a pore size of 3.3 microns.
Further, the pore size of the second screen is 2.3 microns.
Further, the third screen has a pore size of 0.7 μm.
Further, the solvent is deionized water, and the binder is SBR.
Further, the conductive agent is selected from acetylene black, ketjen black or furnace black.
The invention has the following beneficial effects:
1) the natural graphite has wide sources and low cost, but the particle size distribution of the natural graphite is difficult to control, and the particle size distribution of the natural graphite can be adjusted by sieving the natural graphite, so that the stability of the graphite slurry is improved;
2) the inventor carries out high-speed ball milling on the large-particle-size graphite and the small-particle-size graphite particles to ensure that the small-particle-size graphite is coated on the surface of the large-particle-size graphite, so that the small-particle-size graphite and the large-particle-size graphite can be compounded while the conductivity of the large-particle-size graphite is improved, and the condition that the capacity of the negative electrode is attenuated too fast due to excessive small-particle-size graphite in the negative electrode can be prevented;
3) the graphite particles with different particle diameters are mixed according to a specific mass ratio, the particle size distribution of the graphite material is adjusted, and the stability of the slurry can be improved, so that the coating performance is improved, and the cycle life of the cathode is prolonged.
Detailed Description
The present invention will be described in more detail below with reference to specific examples, but the scope of the present invention is not limited to these examples. The graphite material is natural graphite, the average particle size D50 of the graphite material is 2.0 micrometers, the average particle size D10 of the graphite material is 0.6 micrometers, the average particle size D90 of the graphite material is 3.5 micrometers, the solvent is deionized water, the binder is SBR, and the conductive agent is Ketjen black.
Example 1
1) Providing a graphite material having an average particle size D50 of 1.9 microns, D10 of 0.5 microns, and D90 of 3.4 microns;
2) passing a graphite material through a first screen, wherein the aperture of the first screen is 3.2 microns, and collecting the material on the first screen as a first graphite material;
3) collecting the material under the first screen and passing it through a second screen, the second screen having a pore size of 2.2 microns, collecting the material on the second screen as a second graphite material;
4) collecting the material under the second screen and passing through a third screen, wherein the aperture of the third screen is 0.6 micron, and collecting the material on the third screen as a third graphite material;
5) collecting the material under the third screen mesh as a fourth graphite material;
6) mixing the first graphite material and the fourth graphite material according to a mass ratio of 100:25, and placing the mixture in a ball mill for high-speed ball milling, wherein the ball-material ratio of the high-speed ball milling is 2.5:1, the rotating speed is 180 revolutions per minute, and the ball milling time is 10 hours, so that the fourth graphite material is coated on the surface of the first graphite material to form a coating material;
7) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the coating material and the conductive material, and uniformly stirring to obtain a first slurry, wherein the coating material: adhesive: the conductive agent is 100:4: 3;
8) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the second graphite material and the conductive material, and uniformly stirring to obtain a second slurry, wherein the second graphite material: adhesive: the conductive agent is 100:4: 3;
9) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the third graphite material and the conductive material, and uniformly stirring to obtain a third slurry, wherein the third graphite material: adhesive: the conductive agent is 100:4: 3;
10) mixing the first slurry, the second slurry and the third slurry to obtain negative active slurry, wherein the mass ratio of the coating materials: a second graphite material: a third graphite material 24:34: 42;
11) and coating the negative active slurry on the surface of the current collector, wherein the coating thickness is 75 microns, and drying to obtain the graphite negative electrode.
Example 2
1) Providing a graphite material having an average particle size, D50, of 2.1 microns, D10 of 0.7 microns, and D90 of 3.6 microns;
2) passing a graphite material through a first screen, wherein the aperture of the first screen is 3.4 microns, and collecting the material on the first screen as a first graphite material;
3) collecting the material under the first screen and passing it through a second screen, the second screen having a pore size of 2.4 microns, collecting the material on the second screen as a second graphite material;
4) collecting the material under the second screen and passing through a third screen, wherein the aperture of the third screen is 0.8 micron, and collecting the material on the third screen as a third graphite material;
5) collecting the material under the third screen mesh as a fourth graphite material;
6) mixing the first graphite material and the fourth graphite material according to a mass ratio of 100:28, and placing the mixture in a ball mill for high-speed ball milling, wherein the ball-material ratio of the high-speed ball milling is 2.5:1, the rotating speed is 240 revolutions per minute, and the ball milling time is 12 hours, so that the fourth graphite material is coated on the surface of the first graphite material to form a coating material;
7) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the coating material and the conductive material, and uniformly stirring to obtain a first slurry, wherein the coating material: adhesive: the conductive agent is 100:4: 3;
8) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the second graphite material and the conductive material, and uniformly stirring to obtain a second slurry, wherein the second graphite material: adhesive: the conductive agent is 100:4: 3;
9) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the third graphite material and the conductive material, and uniformly stirring to obtain a third slurry, wherein the third graphite material: adhesive: the conductive agent is 100:4: 3;
10) mixing the first slurry, the second slurry and the third slurry to obtain negative active slurry, wherein the mass ratio of the coating materials: a second graphite material: a third graphite material 26:36: 38;
11) and coating the negative active slurry on the surface of the current collector, wherein the coating thickness is 75 microns, and drying to obtain the graphite negative electrode.
Example 3
1) Providing a graphite material having an average particle size, D50, of 2.0 microns, D10 of 0.6 microns, and D90 of 3.5 microns;
2) passing a graphite material through a first screen, wherein the aperture of the first screen is 3.3 microns, and collecting the material on the first screen as a first graphite material;
3) collecting the material under the first screen and passing it through a second screen, the second screen having a pore size of 2.3 microns, collecting the material on the second screen as a second graphite material;
4) collecting the material under the second screen and passing through a third screen, wherein the aperture of the third screen is 0.7 micron, and collecting the material on the third screen as a third graphite material;
5) collecting the material under the third screen mesh as a fourth graphite material;
6) mixing the first graphite material and the fourth graphite material according to a mass ratio of 100:26, and placing the mixture in a ball mill for high-speed ball milling, wherein the ball-material ratio of the high-speed ball milling is 2.5:1, the rotating speed is 220 r/min, and the ball milling time is 12h, so that the fourth graphite material is coated on the surface of the first graphite material to form a coating material;
7) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the coating material and the conductive material, and uniformly stirring to obtain a first slurry, wherein the coating material: adhesive: the conductive agent is 100:4: 3;
8) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the second graphite material and the conductive material, and uniformly stirring to obtain a second slurry, wherein the second graphite material: adhesive: the conductive agent is 100:4: 3;
9) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the third graphite material and the conductive material, and uniformly stirring to obtain a third slurry, wherein the third graphite material: adhesive: the conductive agent is 100:4: 3;
10) mixing the first slurry, the second slurry and the third slurry to obtain negative active slurry, wherein the mass ratio of the coating materials: a second graphite material: a third graphite material 25:35: 40;
11) and coating the negative active slurry on the surface of the current collector, wherein the coating thickness is 75 microns, and drying to obtain the graphite negative electrode.
Comparative example 1
1) Providing a graphite material having an average particle size, D50, of 2.0 microns, D10 of 0.6 microns, and D90 of 3.5 microns;
2) passing a graphite material through a first screen, wherein the aperture of the first screen is 3 microns, and collecting the material on the first screen as a first graphite material;
3) collecting the material under the first screen and passing it through a second screen, the second screen having a pore size of 2 microns, collecting the material on the second screen as a second graphite material;
4) collecting the material under the second screen and passing through a third screen, wherein the aperture of the third screen is 0.5 micron, and collecting the material on the third screen as a third graphite material;
5) collecting the material under the third screen mesh as a fourth graphite material;
6) mixing the first graphite material and the fourth graphite material according to a mass ratio of 100:26, and placing the mixture in a ball mill for high-speed ball milling, wherein the ball-material ratio of the high-speed ball milling is 2.5:1, the rotating speed is 220 r/min, and the ball milling time is 12h, so that the fourth graphite material is coated on the surface of the first graphite material to form a coating material;
7) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the coating material and the conductive material, and uniformly stirring to obtain a first slurry, wherein the coating material: adhesive: the conductive agent is 100:4: 3;
8) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the second graphite material and the conductive material, and uniformly stirring to obtain a second slurry, wherein the second graphite material: adhesive: the conductive agent is 100:4: 3;
9) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the third graphite material and the conductive material, and uniformly stirring to obtain a third slurry, wherein the third graphite material: adhesive: the conductive agent is 100:4: 3;
10) mixing the first slurry, the second slurry and the third slurry to obtain negative active slurry, wherein the mass ratio of the coating materials: a second graphite material: a third graphite material 25:35: 40;
11) and coating the negative active slurry on the surface of the current collector, wherein the coating thickness is 75 microns, and drying to obtain the graphite negative electrode.
Comparative example 2
1) Providing a graphite material having an average particle size, D50, of 2.0 microns, D10 of 0.6 microns, and D90 of 3.5 microns;
2) passing a graphite material through a first screen, wherein the aperture of the first screen is 3.3 microns, and collecting the material on the first screen as a first graphite material;
3) collecting the material under the first screen and passing it through a second screen, the second screen having a pore size of 2.3 microns, collecting the material on the second screen as a second graphite material;
4) collecting the material under the second screen and passing through a third screen, wherein the aperture of the third screen is 0.7 micron, and collecting the material on the third screen as a third graphite material;
5) collecting the material under the third screen mesh as a fourth graphite material;
6) mixing the first graphite material and the fourth graphite material according to a mass ratio of 100:26 to obtain a mixed material;
7) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the mixed material and the conductive material, and uniformly stirring to obtain a first slurry, wherein the mixed material is: adhesive: the conductive agent is 100:4: 3;
8) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the second graphite material and the conductive material, and uniformly stirring to obtain a second slurry, wherein the second graphite material: adhesive: the conductive agent is 100:4: 3;
9) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the third graphite material and the conductive material, and uniformly stirring to obtain a third slurry, wherein the third graphite material: adhesive: the conductive agent is 100:4: 3;
10) mixing the first slurry, the second slurry and the third slurry to obtain negative active slurry, wherein the mass ratio of the mixed materials is as follows: a second graphite material: a third graphite material 25:35: 40;
11) and coating the negative active slurry on the surface of the current collector, wherein the coating thickness is 75 microns, and drying to obtain the graphite negative electrode.
Comparative example 3
1) Providing a graphite material having an average particle size, D50, of 2.0 microns, D10 of 0.6 microns, and D90 of 3.5 microns;
2) passing a graphite material through a first screen, wherein the aperture of the first screen is 3.3 microns, and collecting the material on the first screen as a first graphite material;
3) collecting the material under the first screen and passing it through a second screen, the second screen having a pore size of 2.3 microns, collecting the material on the second screen as a second graphite material;
4) collecting the material under the second screen and passing through a third screen, wherein the aperture of the third screen is 0.7 micron, and collecting the material on the third screen as a third graphite material;
5) collecting the material under the third screen mesh as a fourth graphite material;
6) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the first graphite material and the conductive material, and uniformly stirring to obtain a first slurry, wherein the first graphite material: adhesive: the conductive agent is 100:4: 3;
7) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the second graphite material and the conductive material, and uniformly stirring to obtain a second slurry, wherein the second graphite material: adhesive: the conductive agent is 100:4: 3;
8) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the third graphite material and the conductive material, and uniformly stirring to obtain a third slurry, wherein the third graphite material: adhesive: the conductive agent is 100:4: 3;
9) mixing the first slurry, the second slurry and the third slurry to obtain negative active slurry, wherein the mass ratio of the first graphite material: a second graphite material: a third graphite material 25:35: 40;
10) and coating the negative active slurry on the surface of the current collector, wherein the coating thickness is 75 microns, and drying to obtain the graphite negative electrode.
Comparative example 4
1) Providing a graphite material having an average particle size, D50, of 2.0 microns, D10 of 0.6 microns, and D90 of 3.5 microns;
2) passing a graphite material through a first screen, wherein the aperture of the first screen is 3.3 microns, and collecting the material on the first screen as a first graphite material;
3) collecting the material under the first screen and passing it through a second screen, the second screen having a pore size of 2.3 microns, collecting the material on the second screen as a second graphite material;
4) collecting the material under the second screen and passing through a third screen, wherein the aperture of the third screen is 0.7 micron, and collecting the material on the third screen as a third graphite material;
5) collecting the material under the third screen mesh as a fourth graphite material;
6) mixing the first graphite material and the fourth graphite material according to a mass ratio of 100:26, and placing the mixture in a ball mill for high-speed ball milling, wherein the ball-material ratio of the high-speed ball milling is 2.5:1, the rotating speed is 220 r/min, and the ball milling time is 12h, so that the fourth graphite material is coated on the surface of the first graphite material to form a coating material;
7) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the coating material and the conductive material, and uniformly stirring to obtain a first slurry, wherein the coating material: adhesive: the conductive agent is 100:4: 3;
8) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the second graphite material and the conductive material, and uniformly stirring to obtain a second slurry, wherein the second graphite material: adhesive: the conductive agent is 100:4: 3;
9) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the third graphite material and the conductive material, and uniformly stirring to obtain a third slurry, wherein the third graphite material: adhesive: the conductive agent is 100:4: 3;
10) mixing the first slurry, the second slurry and the third slurry to obtain negative active slurry, wherein the mass ratio of the coating materials: a second graphite material: a third graphite material 30:30: 40;
11) and coating the negative active slurry on the surface of the current collector, wherein the coating thickness is 75 microns, and drying to obtain the graphite negative electrode.
Test and results
The slurries of examples 1 to 3 and comparative examples 1 to 4 were tested to have an initial solid content of 50%, and the solid content at a position 5cm below the top of the slurry was measured after standing for 10 hours, the results are shown in table 1, and the obtained graphite negative electrode and a lithium sheet were combined to form an experimental battery, and charge-discharge cycles were performed 500 times using a current of 1C, and the cycle capacity retention rate of the battery was measured, and the results are shown in table 1. As can be seen from table 1, the large-particle-size graphite and the small-particle-size graphite particles are subjected to high-speed ball milling, so that the small-particle-size graphite is coated on the surface of the large-particle-size graphite, the conductivity of the large-particle-size graphite can be improved, the small-particle-size graphite and the large-particle-size graphite are compounded, and the situation that the capacity of the negative electrode is attenuated too fast due to excessive small-particle-size graphite in the negative electrode can be prevented; the graphite particles with different particle diameters are mixed according to a specific mass ratio, the particle size distribution of the graphite material is adjusted, and the stability of the slurry can be improved, so that the coating performance is improved, and the cycle life of the negative electrode is prolonged
TABLE 1
| Solid content of the slurry% | Retention ratio of circulating Capacity (%) | |
| Example 1 | 47.5 | 99.2 |
| Example 2 | 47.8 | 99.1 |
| Example 3 | 48.2 | 99.5 |
| Comparative example 1 | 44.3 | 96.4 |
| Comparative example 2 | 43.9 | 96.1 |
| Comparative example 3 | 46.8 | 94.3 |
| Comparative example 4 | 43.2 | 96.6 |
While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention.
Claims (9)
1. A method of making a graphite anode, the method comprising:
1) providing a graphite material having an average particle size, D50, of 1.9-2.1 microns, D10 of 0.5-0.7 microns, and D90 of 3.4-3.6 microns;
2) passing a graphite material through a first screen, wherein the aperture of the first screen is 3.2-3.4 microns, and collecting the material on the first screen as a first graphite material;
3) collecting the material under the first screen and passing it through a second screen, the second screen having a pore size of 2.2-2.4 microns, and collecting the material on the second screen as a second graphite material;
4) collecting the material under the second screen and passing through a third screen, wherein the aperture of the third screen is 0.6-0.8 micron, and collecting the material on the third screen as a third graphite material;
5) collecting the material under the third screen mesh as a fourth graphite material;
6) mixing the first graphite material and the fourth graphite material according to the mass ratio of 100:25-28, and placing the mixture in a ball mill for high-speed ball milling to ensure that the fourth graphite material is coated on the surface of the first graphite material to form a coating material;
7) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, then adding the coating material and the conductive material, and uniformly stirring to obtain a first slurry;
8) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, adding the second graphite material and the conductive material, and uniformly stirring to obtain a second slurry;
9) adding a solvent into a stirring kettle, adding a binder into the solvent, uniformly stirring, adding the third graphite material and the conductive material, and uniformly stirring to obtain a third slurry;
10) mixing the first slurry, the second slurry and the third slurry to obtain negative active slurry, wherein the mass ratio of the coating materials: a second graphite material: a third graphite material 24:34:42-26:36: 38;
11) and coating the negative active slurry on the surface of the current collector, and drying to obtain the graphite negative electrode.
2. The method as claimed in the preceding claim, wherein in the high-speed ball milling, the ball-to-material ratio is 2.5:1, the rotation speed is 180-.
3. The method of the preceding claim, wherein the graphite material is natural graphite.
4. The method of any preceding claim, wherein the graphite material has an average particle size of D50 of 2.0 microns, D10 of 0.6 microns, and D90 of 3.5 microns.
5. The method of the preceding claim, wherein the first screen has a pore size of 3.3 microns.
6. The method of the preceding claim, wherein the second screen has a pore size of 2.3 microns.
7. The method of the preceding claim, wherein the third screen has a pore size of 0.7 microns.
8. The method of the preceding claim, wherein the solvent is deionized water and the binder is SBR.
9. The method of the preceding claim, wherein the conductive agent is selected from acetylene black, ketjen black, or furnace black.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011062378.6A CN112117450A (en) | 2020-09-30 | 2020-09-30 | Preparation method of graphite cathode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011062378.6A CN112117450A (en) | 2020-09-30 | 2020-09-30 | Preparation method of graphite cathode |
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| Publication Number | Publication Date |
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| CN112117450A true CN112117450A (en) | 2020-12-22 |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007220324A (en) * | 2006-02-14 | 2007-08-30 | Kansai Coke & Chem Co Ltd | Negative electrode material for lithium ion secondary battery and its manufacturing method |
| CN101192662A (en) * | 2006-11-30 | 2008-06-04 | 比亚迪股份有限公司 | Battery cathode and lithium ion secondary battery comprising same |
| CN107112536A (en) * | 2015-01-16 | 2017-08-29 | 三菱化学株式会社 | Carbon material and the non-aqueous secondary battery for having used carbon material |
| CN111370670A (en) * | 2020-03-19 | 2020-07-03 | 陆晨杰 | Mixing method of negative electrode slurry |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007220324A (en) * | 2006-02-14 | 2007-08-30 | Kansai Coke & Chem Co Ltd | Negative electrode material for lithium ion secondary battery and its manufacturing method |
| CN101192662A (en) * | 2006-11-30 | 2008-06-04 | 比亚迪股份有限公司 | Battery cathode and lithium ion secondary battery comprising same |
| CN107112536A (en) * | 2015-01-16 | 2017-08-29 | 三菱化学株式会社 | Carbon material and the non-aqueous secondary battery for having used carbon material |
| CN111370670A (en) * | 2020-03-19 | 2020-07-03 | 陆晨杰 | Mixing method of negative electrode slurry |
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