CN113363425A - Preparation method of anode of lithium ion battery - Google Patents

Preparation method of anode of lithium ion battery Download PDF

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Publication number
CN113363425A
CN113363425A CN202110566976.5A CN202110566976A CN113363425A CN 113363425 A CN113363425 A CN 113363425A CN 202110566976 A CN202110566976 A CN 202110566976A CN 113363425 A CN113363425 A CN 113363425A
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screen
graphite material
slurry
pore size
average pore
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郭卫星
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Zhejiang Lunqin Radiation Protection Engineering Co ltd
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Zhejiang Lunqin Radiation Protection Engineering 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D37/00—Processes of filtration
    • B01D37/04—Controlling the filtration
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • 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
    • 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
    • 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

Abstract

The invention provides a preparation method of a lithium ion battery anode, wherein the anode comprises a current collector, and a first active material layer, a second active material layer and a third active material layer which are sequentially stacked on the current collector; the preparation method comprises the following steps: providing a graphite material, sieving the graphite material, and sieving the graphite material into a graphite material A, a graphite material B, a graphite material C and a graphite material D according to the difference of the aperture of a sieve mesh; then, according to a preset mass ratio, respectively taking partial graphite materials in the graphite material A, the graphite material B, the graphite material C and the graphite material D, mixing to prepare a first slurry, a second slurry and a third slurry, and then sequentially coating the slurries on a current collector; and drying and hot-pressing to obtain the anode of the lithium ion battery. The lithium ion battery anode obtained by the preparation method has good stability to electrolyte, and the active substance has high structural stability and good cycle performance.

Description

Preparation method of anode of lithium ion battery
Technical Field
The invention relates to a preparation method of an anode of a lithium ion battery.
Background
The anode active material of the lithium ion battery mainly comprises graphite materials, natural graphite is wide in source and low in cost, but the particle size of the natural graphite is difficult to control, and the performance is unstable, so that if a preparation method can be provided, the performance of taking the natural graphite as an anode can be improved, and the manufacturing cost of the lithium ion battery can be effectively reduced.
Disclosure of Invention
The invention provides a preparation method of a lithium ion battery anode, wherein the anode comprises a current collector, and a first active material layer, a second active material layer and a third active material layer which are sequentially stacked on the current collector; the preparation method comprises the following steps: providing a graphite material, sieving the graphite material, and sieving the graphite material into a graphite material A, a graphite material B, a graphite material C and a graphite material D according to the difference of the aperture of a sieve mesh; then, according to a preset mass ratio, respectively taking partial graphite materials in the graphite material A, the graphite material B, the graphite material C and the graphite material D, mixing to prepare first slurry, second slurry and third slurry, and then sequentially coating the slurries on a current collector to obtain a laminated first active material layer, a laminated second active material layer and a laminated third active material layer; and drying and hot-pressing to obtain the anode of the lithium ion battery. The lithium ion battery anode obtained by the preparation method has good stability to electrolyte, and the active substance has high structural stability and good cycle performance. The specific scheme is as follows:
the preparation method of the anode of the lithium ion battery comprises the steps that the anode comprises a current collector, and a first active material layer, a second active material layer and a third active material layer which are sequentially stacked on the current collector; the preparation method comprises the following steps:
1) providing a graphite material, enabling the graphite material to pass through a first screen, enabling the material below the first screen to pass through a second screen, and collecting the material on the second screen to serve as the graphite material A;
2) passing the material under the second screen through a third screen, and collecting the material on the third screen as a graphite material B;
3) passing the material under the third screen through a fourth screen, and collecting the material on the fourth screen as a graphite material C;
4) passing the material under the fourth screen through a fifth screen, and collecting the material on the fifth screen as a graphite material D;
5) uniformly mixing the graphite material B and the graphite material C, wherein the mass ratio of the graphite material B: graphite material C ═ k1 (average pore size of the second screen + average pore size of the third screen)/(average pore size of the third screen + average pore size of the fourth screen); wherein k1 is 1.45-1.48; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain first slurry;
6) uniformly mixing the graphite material C and the graphite material D, wherein the mass ratio of the graphite material C: graphite material D ═ k2 (average pore size of third screen + average pore size of fourth screen)/(average pore size of fourth screen + average pore size of fifth screen); wherein k2 is 2.82-2.85; sequentially adding the binder, the mixed graphite material and the conductive agent into deionized water to obtain second slurry;
7) uniformly mixing a graphite material A and a graphite material B, wherein the mass ratio of the graphite material A: graphite material B ═ k3 ═ k (average pore size of first screen + average pore size of second screen)/(average pore size of second screen + average pore size of third screen); wherein k3 is 0.75-0.78; sequentially adding the binder, the mixed graphite material and the conductive agent into deionized water to obtain third slurry;
8) sequentially coating the first slurry, the second slurry and the third slurry on a current collector to obtain a first active material layer, a second active material layer and a third active material layer which are laminated; and drying and hot-pressing to obtain the anode of the lithium ion battery.
It is further preferred that the first screen has an average pore size of 3.8 microns, and it is further preferred that the second screen has an average pore size of 3.2 microns.
It is further preferred that the average pore size of the third screen is 2.6 microns, it is further preferred that the average pore size of the fourth screen is 2.0 microns, and it is further preferred that the average pore size of the fifth screen is 1.4 microns.
Further preferably, in the first slurry, the ratio of graphite material: adhesive: the conductive agent is 100:4.6: 6-8; further preferably, in the second slurry, the ratio of graphite material: adhesive: the conductive agent is 100:4.2: 3-5; further preferably, in the third slurry, the ratio of graphite material: adhesive: the conductive agent is 100:5.2: 8-10.
Further preferably, the graphite material is selected from natural graphite; further preferably, the binder is SBR; further preferably, the conductive agent is selected from conductive carbon black, carbon nanotubes, nano metal particles and conductive high molecular polymers.
Further preferably, the thickness ratio of the first active material layer, the second active material layer and the third active material layer is 15-20:40-60: 10-15.
Further preferably, the lithium ion battery anode is prepared by the method.
Further preferably, a lithium ion battery comprises the anode.
The invention has the following beneficial effects:
1) graphite particles with specific particle size distribution are arranged at a specific position of the active material layer by limiting the average pore size of the screen, and a graphite material with higher porosity and larger particle size is arranged at the bottom layer position, so that the wetting performance of the electrolyte at the bottom of the electrode active material layer is improved; the middle layer is arranged to be a layer with the highest compaction density so as to improve the energy density of the cathode, the surface layer is arranged to be a graphite layer with the lowest specific surface area and the largest particle size so as to improve the stability of the cathode surface to electrolyte and improve the electron conduction rate of the surface layer;
2) the inventors further found that when the binder of the first slurry, the second slurry and the third slurry is at a specific value, the graphite component in the slurry is adjusted to satisfy a specific mass ratio, that is, in the first slurry, the graphite material: binder 100: 4.6; and (3) graphite material B: graphite material C ═ k1 (average pore size of the second screen + average pore size of the third screen)/(average pore size of the third screen + average pore size of the fourth screen); wherein k1 is 1.45-1.48; the slurry with extremely high stability can be obtained, and the coating performance of the slurry is improved; the stability of the active material layer is improved;
3) and in the second slurry, a graphite material: binder 100: 4.2; a graphite material C: graphite material D ═ k2 (average pore size of third screen + average pore size of fourth screen)/(average pore size of fourth screen + average pore size of fifth screen); wherein k2 is 2.82-2.85; the slurry with extremely high stability can be obtained, the coating performance of the slurry is improved, and the stability of an active material layer is improved;
4) and in the third slurry, a graphite material: binder 100: 5.2; graphite material A: graphite material B ═ k3 ═ k (average pore size of first screen + average pore size of second screen)/(average pore size of second screen + average pore size of third screen); when k3 is 0.75-0.78, slurry with extremely high stability can be obtained, the coating performance of the slurry is improved, and the stability of an active material layer is improved;
5) the thickness ratio of the first active material layer to the second active material layer to the third active material layer is 15-20:40-60:10-15, and an anode having excellent rate performance and cycle performance can be obtained.
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 selected from natural graphite; the binder is SBR; the conductive agent is selected from conductive carbon black.
Example 1
1) Providing a graphite material, enabling the graphite material to pass through a first screen, enabling the material below the first screen to pass through a second screen, and collecting the material on the second screen to serve as the graphite material A; the first screen had an average pore size of 3.8 microns and the second screen had an average pore size of 3.2 microns;
2) passing the material under the second screen through a third screen, and collecting the material on the third screen as a graphite material B; the third screen had an average pore size of 2.6 microns;
3) passing the material under the third screen through a fourth screen, and collecting the material on the fourth screen as graphite material C, wherein the average pore size of the fourth screen is 2.0 microns;
4) passing the material under the fourth screen through a fifth screen, and collecting the material on the fifth screen as graphite material D, wherein the average pore size of the fifth screen is 1.4 microns;
5) uniformly mixing the graphite material B and the graphite material C, wherein the mass ratio of the graphite material B: graphite material C ═ 1.45 ═ (3.2+2.6)/(2.6+2.0) ═ 1.83: 1; sequentially adding a binder, a mixed graphite material and a conductive agent into deionized water to obtain first slurry, wherein in the first slurry, the graphite material: adhesive: the conductive agent is 100:4.6: 6;
6) uniformly mixing the graphite material C and the graphite material D, wherein the mass ratio of the graphite material C: graphite material D ═ 2.82 ═ (2.6+2.0)/(2.0+1.4) ═ 3.82: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain second slurry, wherein in the second slurry, the graphite material: adhesive: the conductive agent is 100:4.2: 3;
7) uniformly mixing a graphite material A and a graphite material B, wherein the mass ratio of the graphite material A: graphite material B0.75 ═ 0.91:1 (3.8+3.2)/(3.2+ 2.6); sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain third slurry, wherein in the third slurry, the graphite material: adhesive: the conductive agent is 100:5.2: 8;
8) sequentially coating the first slurry, the second slurry and the third slurry on a current collector to obtain a first active material layer, a second active material layer and a third active material layer which are laminated; the thickness ratio of the first active material layer, the second active material layer and the third active material layer is 15:40: 10; and drying and hot-pressing to obtain the anode of the lithium ion battery.
Example 2
1) Providing a graphite material, enabling the graphite material to pass through a first screen, enabling the material below the first screen to pass through a second screen, and collecting the material on the second screen to serve as the graphite material A; the first screen had an average pore size of 3.8 microns and the second screen had an average pore size of 3.2 microns;
2) passing the material under the second screen through a third screen, and collecting the material on the third screen as a graphite material B; the third screen had an average pore size of 2.6 microns;
3) passing the material under the third screen through a fourth screen, and collecting the material on the fourth screen as graphite material C, wherein the average pore size of the fourth screen is 2.0 microns;
4) passing the material under the fourth screen through a fifth screen, and collecting the material on the fifth screen as graphite material D, wherein the average pore size of the fifth screen is 1.4 microns;
5) uniformly mixing the graphite material B and the graphite material C, wherein the mass ratio of the graphite material B: graphite material C ═ 1.48 ═ (3.2+2.6)/(2.6+2.0) ═ 1.87: 1; sequentially adding a binder, a mixed graphite material and a conductive agent into deionized water to obtain first slurry, wherein in the first slurry, the graphite material: adhesive: the conductive agent is 100:4.6: 8;
6) uniformly mixing the graphite material C and the graphite material D, wherein the mass ratio of the graphite material C: graphite material D ═ 2.85 ═ (2.6+2.0)/(2.0+1.4) ═ 3.86: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain second slurry, wherein in the second slurry, the graphite material: adhesive: the conductive agent is 100:4.2: 5;
7) uniformly mixing a graphite material A and a graphite material B, wherein the mass ratio of the graphite material A: graphite material B0.78 ═ (3.8+3.2)/(3.2+2.6) ═ 0.94: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain third slurry, wherein in the third slurry, the graphite material: adhesive: the conductive agent is 100:5.2: 10;
8) sequentially coating the first slurry, the second slurry and the third slurry on a current collector to obtain a first active material layer, a second active material layer and a third active material layer which are laminated; the thickness ratio of the first active material layer, the second active material layer and the third active material layer is 20:60: 15; and drying and hot-pressing to obtain the anode of the lithium ion battery.
Example 3
1) Providing a graphite material, enabling the graphite material to pass through a first screen, enabling the material below the first screen to pass through a second screen, and collecting the material on the second screen to serve as the graphite material A; the first screen had an average pore size of 3.8 microns and the second screen had an average pore size of 3.2 microns;
2) passing the material under the second screen through a third screen, and collecting the material on the third screen as a graphite material B; the third screen had an average pore size of 2.6 microns;
3) passing the material under the third screen through a fourth screen, and collecting the material on the fourth screen as graphite material C, wherein the average pore size of the fourth screen is 2.0 microns;
4) passing the material under the fourth screen through a fifth screen, and collecting the material on the fifth screen as graphite material D, wherein the average pore size of the fifth screen is 1.4 microns;
5) uniformly mixing the graphite material B and the graphite material C, wherein the mass ratio of the graphite material B: graphite material C ═ 1.46 (3.2+2.6)/(2.6+2.0) ═ 1.84: 1; sequentially adding a binder, a mixed graphite material and a conductive agent into deionized water to obtain first slurry, wherein in the first slurry, the graphite material: adhesive: the conductive agent is 100:4.6: 7;
6) uniformly mixing the graphite material C and the graphite material D, wherein the mass ratio of the graphite material C: graphite material D ═ 2.84 ═ (2.6+2.0)/(2.0+1.4) ═ 3.84: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain second slurry, wherein in the second slurry, the graphite material: adhesive: the conductive agent is 100:4.2: 4;
7) uniformly mixing a graphite material A and a graphite material B, wherein the mass ratio of the graphite material A: graphite material B0.76 ═ (3.8+3.2)/(3.2+2.6) ═ 0.92: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain third slurry, wherein in the third slurry, the graphite material: adhesive: the conductive agent is 100:5.2: 9;
8) sequentially coating the first slurry, the second slurry and the third slurry on a current collector to obtain a first active material layer, a second active material layer and a third active material layer which are laminated; the thickness ratio of the first active material layer, the second active material layer and the third active material layer is 18:50: 12; and drying and hot-pressing to obtain the anode of the lithium ion battery.
Comparative example 1
1) Providing a graphite material, enabling the graphite material to pass through a first screen, enabling the material below the first screen to pass through a second screen, and collecting the material on the second screen to serve as the graphite material A; the first screen had an average pore size of 3.5 microns and the second screen had an average pore size of 3.0 microns;
2) passing the material under the second screen through a third screen, and collecting the material on the third screen as a graphite material B; the third screen had an average pore size of 2.2 microns;
3) passing the material under the third screen through a fourth screen, and collecting the material on the fourth screen as graphite material C, wherein the average pore size of the fourth screen is 1.8 microns;
4) passing the material under the fourth screen through a fifth screen, and collecting the material on the fifth screen as graphite material D, wherein the average pore size of the fifth screen is 1.2 microns;
5) uniformly mixing the graphite material B and the graphite material C, wherein the mass ratio of the graphite material B: graphite material C1.84: 1; sequentially adding a binder, a mixed graphite material and a conductive agent into deionized water to obtain first slurry, wherein in the first slurry, the graphite material: adhesive: the conductive agent is 100:4.6: 7;
6) uniformly mixing the graphite material C and the graphite material D, wherein the mass ratio of the graphite material C: graphite material D is 3.84: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain second slurry, wherein in the second slurry, the graphite material: adhesive: the conductive agent is 100:4.2: 4;
7) uniformly mixing a graphite material A and a graphite material B, wherein the mass ratio of the graphite material A: graphite material B is 0.92: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain third slurry, wherein in the third slurry, the graphite material: adhesive: the conductive agent is 100:5.2: 9;
8) sequentially coating the first slurry, the second slurry and the third slurry on a current collector to obtain a first active material layer, a second active material layer and a third active material layer which are laminated; the thickness ratio of the first active material layer, the second active material layer and the third active material layer is 18:50: 12; and drying and hot-pressing to obtain the anode of the lithium ion battery.
Comparative example 2
1) Providing a graphite material, enabling the graphite material to pass through a first screen, enabling the material below the first screen to pass through a second screen, and collecting the material on the second screen to serve as the graphite material A; the first screen had an average pore size of 4.2 microns and the second screen had an average pore size of 3.6 microns;
2) passing the material under the second screen through a third screen, and collecting the material on the third screen as a graphite material B; the third screen had an average pore size of 2.8 microns;
3) passing the material under the third screen through a fourth screen, and collecting the material on the fourth screen as graphite material C, wherein the average pore size of the fourth screen is 2.4 microns;
4) passing the material under the fourth screen through a fifth screen, and collecting the material on the fifth screen as graphite material D, wherein the average pore size of the fifth screen is 1.8 microns;
5) uniformly mixing the graphite material B and the graphite material C, wherein the mass ratio of the graphite material B: graphite material C1.84: 1; sequentially adding a binder, a mixed graphite material and a conductive agent into deionized water to obtain first slurry, wherein in the first slurry, the graphite material: adhesive: the conductive agent is 100:4.6: 7;
6) uniformly mixing the graphite material C and the graphite material D, wherein the mass ratio of the graphite material C: graphite material D is 3.84: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain second slurry, wherein in the second slurry, the graphite material: adhesive: the conductive agent is 100:4.2: 4;
7) uniformly mixing a graphite material A and a graphite material B, wherein the mass ratio of the graphite material A: graphite material B is 0.92: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain third slurry, wherein in the third slurry, the graphite material: adhesive: the conductive agent is 100:5.2: 9;
8) sequentially coating the first slurry, the second slurry and the third slurry on a current collector to obtain a first active material layer, a second active material layer and a third active material layer which are laminated; the thickness ratio of the first active material layer, the second active material layer and the third active material layer is 18:50: 12; and drying and hot-pressing to obtain the anode of the lithium ion battery.
Comparative example 3
1) Providing a graphite material, enabling the graphite material to pass through a first screen, enabling the material below the first screen to pass through a second screen, and collecting the material on the second screen to serve as the graphite material A; the first screen had an average pore size of 3.8 microns and the second screen had an average pore size of 3.2 microns;
2) passing the material under the second screen through a third screen, and collecting the material on the third screen as a graphite material B; the third screen had an average pore size of 2.6 microns;
3) passing the material under the third screen through a fourth screen, and collecting the material on the fourth screen as graphite material C, wherein the average pore size of the fourth screen is 2.0 microns;
4) passing the material under the fourth screen through a fifth screen, and collecting the material on the fifth screen as graphite material D, wherein the average pore size of the fifth screen is 1.4 microns;
5) uniformly mixing the graphite material B and the graphite material C, wherein the mass ratio of the graphite material B: graphite material C is 1.90: 1; sequentially adding a binder, a mixed graphite material and a conductive agent into deionized water to obtain first slurry, wherein in the first slurry, the graphite material: adhesive: the conductive agent is 100:4.6: 7;
6) uniformly mixing the graphite material C and the graphite material D, wherein the mass ratio of the graphite material C: graphite material D is 3.95: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain second slurry, wherein in the second slurry, the graphite material: adhesive: the conductive agent is 100:4.2: 4;
7) uniformly mixing a graphite material A and a graphite material B, wherein the mass ratio of the graphite material A: graphite material B is 1: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain third slurry, wherein in the third slurry, the graphite material: adhesive: the conductive agent is 100:5.2: 9;
8) sequentially coating the first slurry, the second slurry and the third slurry on a current collector to obtain a first active material layer, a second active material layer and a third active material layer which are laminated; the thickness ratio of the first active material layer, the second active material layer and the third active material layer is 18:50: 12; and drying and hot-pressing to obtain the anode of the lithium ion battery.
Comparative example 4
1) Providing a graphite material, enabling the graphite material to pass through a first screen, enabling the material below the first screen to pass through a second screen, and collecting the material on the second screen to serve as the graphite material A; the first screen had an average pore size of 3.8 microns and the second screen had an average pore size of 3.2 microns;
2) passing the material under the second screen through a third screen, and collecting the material on the third screen as a graphite material B; the third screen had an average pore size of 2.6 microns;
3) passing the material under the third screen through a fourth screen, and collecting the material on the fourth screen as graphite material C, wherein the average pore size of the fourth screen is 2.0 microns;
4) passing the material under the fourth screen through a fifth screen, and collecting the material on the fifth screen as graphite material D, wherein the average pore size of the fifth screen is 1.4 microns;
5) uniformly mixing the graphite material B and the graphite material C, wherein the mass ratio of the graphite material B: graphite material C is 1.70: 1; sequentially adding a binder, a mixed graphite material and a conductive agent into deionized water to obtain first slurry, wherein in the first slurry, the graphite material: adhesive: the conductive agent is 100:4.6: 7;
6) uniformly mixing the graphite material C and the graphite material D, wherein the mass ratio of the graphite material C: graphite material D is 3.70: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain second slurry, wherein in the second slurry, the graphite material: adhesive: the conductive agent is 100:4.2: 4;
7) uniformly mixing a graphite material A and a graphite material B, wherein the mass ratio of the graphite material A: graphite material B is 0.80: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain third slurry, wherein in the third slurry, the graphite material: adhesive: the conductive agent is 100:5.2: 9;
8) sequentially coating the first slurry, the second slurry and the third slurry on a current collector to obtain a first active material layer, a second active material layer and a third active material layer which are laminated; the thickness ratio of the first active material layer, the second active material layer and the third active material layer is 18:50: 12; and drying and hot-pressing to obtain the anode of the lithium ion battery.
Comparative example 5
1) Providing a graphite material, enabling the graphite material to pass through a first screen, enabling the material below the first screen to pass through a second screen, and collecting the material on the second screen to serve as the graphite material A; the first screen had an average pore size of 3.8 microns and the second screen had an average pore size of 3.2 microns;
2) passing the material under the second screen through a third screen, and collecting the material on the third screen as a graphite material B; the third screen had an average pore size of 2.6 microns;
3) passing the material under the third screen through a fourth screen, and collecting the material on the fourth screen as graphite material C, wherein the average pore size of the fourth screen is 2.0 microns;
4) passing the material under the fourth screen through a fifth screen, and collecting the material on the fifth screen as graphite material D, wherein the average pore size of the fifth screen is 1.4 microns;
5) uniformly mixing the graphite material B and the graphite material C, wherein the mass ratio of the graphite material B: graphite material C ═ 1.46 (3.2+2.6)/(2.6+2.0) ═ 1.84: 1; sequentially adding a binder, a mixed graphite material and a conductive agent into deionized water to obtain first slurry, wherein in the first slurry, the graphite material: adhesive: the conductive agent is 100:4.6: 7;
6) uniformly mixing the graphite material C and the graphite material D, wherein the mass ratio of the graphite material C: graphite material D ═ 2.84 ═ (2.6+2.0)/(2.0+1.4) ═ 3.84: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain second slurry, wherein in the second slurry, the graphite material: adhesive: the conductive agent is 100:4.2: 4;
7) uniformly mixing a graphite material A and a graphite material B, wherein the mass ratio of the graphite material A: graphite material B0.76 ═ (3.8+3.2)/(3.2+2.6) ═ 0.92: 1; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain third slurry, wherein in the third slurry, the graphite material: adhesive: the conductive agent is 100:5.2: 9;
8) mixing the first slurry, the second slurry and the third slurry in sequence according to the mass ratio of 18:50:12, and then coating the mixture on a current collector to obtain a laminated active material layer; and drying and hot-pressing to obtain the anode of the lithium ion battery.
Test and results
The active material slurries of examples 1 to 3 and comparative examples 1 to 4 were tested, the initial solid content was 50%, stored at normal temperature for 20 hours, and the solid content 5cm below the top layer of the slurry was measured to represent the stability of the slurry; the lithium sheets of the anodes and the counter electrodes of examples 1 to 3 and comparative examples 1 to 5 were combined to constitute a test battery, and the cycle capacity retention ratio of the battery was measured by performing a charge and discharge cycle 400 times using a current of 1C, and the results are shown in table 1.
TABLE 1
Figure BDA0003081265230000091
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 (8)

1. The preparation method of the anode of the lithium ion battery comprises the steps that the anode comprises a current collector, and a first active material layer, a second active material layer and a third active material layer which are sequentially stacked on the current collector; the preparation method comprises the following steps:
1) providing a graphite material, enabling the graphite material to pass through a first screen, enabling the material below the first screen to pass through a second screen, and collecting the material on the second screen to serve as the graphite material A;
2) passing the material under the second screen through a third screen, and collecting the material on the third screen as a graphite material B;
3) passing the material under the third screen through a fourth screen, and collecting the material on the fourth screen as a graphite material C;
4) passing the material under the fourth screen through a fifth screen, and collecting the material on the fifth screen as a graphite material D;
5) uniformly mixing the graphite material B and the graphite material C, wherein the mass ratio of the graphite material B: graphite material C ═ k1 (average pore size of the second screen + average pore size of the third screen)/(average pore size of the third screen + average pore size of the fourth screen); wherein k1 is 1.45-1.48; sequentially adding a binder, the mixed graphite material and a conductive agent into deionized water to obtain first slurry;
6) uniformly mixing the graphite material C and the graphite material D, wherein the mass ratio of the graphite material C: graphite material D ═ k2 (average pore size of third screen + average pore size of fourth screen)/(average pore size of fourth screen + average pore size of fifth screen); wherein k2 is 2.82-2.85; sequentially adding the binder, the mixed graphite material and the conductive agent into deionized water to obtain second slurry;
7) uniformly mixing a graphite material A and a graphite material B, wherein the mass ratio of the graphite material A: graphite material B ═ k3 ═ k (average pore size of first screen + average pore size of second screen)/(average pore size of second screen + average pore size of third screen); wherein k3 is 0.75-0.78; sequentially adding the binder, the mixed graphite material and the conductive agent into deionized water to obtain third slurry;
8) sequentially coating the first slurry, the second slurry and the third slurry on a current collector to obtain a first active material layer, a second active material layer and a third active material layer which are laminated; and drying and hot-pressing to obtain the anode of the lithium ion battery.
2. The method of claim, further preferably, the first screen has an average pore size of 3.8 microns, and further preferably, the second screen has an average pore size of 3.2 microns.
3. The method of claim, further preferably, the third screen has an average pore size of 2.6 microns, further preferably, the fourth screen has an average pore size of 2.0 microns, and further preferably, the fifth screen has an average pore size of 1.4 microns.
4. The method according to the preceding claim, further preferably, in the first slurry, the ratio of graphite material: adhesive: the conductive agent is 100:4.6: 6-8; further preferably, in the second slurry, the ratio of graphite material: adhesive: the conductive agent is 100:4.2: 3-5; further preferably, in the third slurry, the ratio of graphite material: adhesive: the conductive agent is 100:5.2: 8-10.
5. The method according to the preceding claim, further preferably, the graphite material is selected from natural graphite; further preferably, the binder is SBR; further preferably, the conductive agent is selected from conductive carbon black, carbon nanotubes, nano metal particles and conductive high molecular polymers.
6. The production method according to the above claim, wherein the thickness ratio of the first active material layer, the second active material layer and the third active material layer is 15-20:40-60: 10-15.
7. A lithium ion battery anode prepared by the method of any one of claims 1-6.
8. A lithium ion battery comprising the anode of claim 7.
CN202110566976.5A 2021-05-24 2021-05-24 Preparation method of anode of lithium ion battery Withdrawn CN113363425A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116026731A (en) * 2022-11-17 2023-04-28 山东希诚新材料科技有限公司 Method for judging whether dispersion of carbon nano tube slurry meets standard by in-situ identification of particle size

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116026731A (en) * 2022-11-17 2023-04-28 山东希诚新材料科技有限公司 Method for judging whether dispersion of carbon nano tube slurry meets standard by in-situ identification of particle size
CN116026731B (en) * 2022-11-17 2024-01-12 山东希诚新材料科技有限公司 Method for judging whether dispersion of carbon nano tube slurry meets standard by in-situ identification of particle size

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