CN111710834A - Preparation method of lithium secondary battery anode - Google Patents

Preparation method of lithium secondary battery anode Download PDF

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CN111710834A
CN111710834A CN202010530192.2A CN202010530192A CN111710834A CN 111710834 A CN111710834 A CN 111710834A CN 202010530192 A CN202010530192 A CN 202010530192A CN 111710834 A CN111710834 A CN 111710834A
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朱虎
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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
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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
    • H01M2004/028—Positive 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 provides a preparation method of a lithium secondary battery anode, which comprises the steps of providing an active substance A and an active substance B, and sieving the active substance A to obtain a first active substance A and a second active substance A; sieving the active substance B to obtain a first active substance B and a second active substance B; the method comprises the steps of mixing a first active substance A and a second active substance B according to a preset proportion to obtain a first slurry, mixing the second active substance A and the first active substance B according to a preset proportion to obtain a second slurry, then sequentially coating the first slurry and the second slurry on a current collector for drying, and then placing a dried pole piece and a counter electrode into an electrolyte for pre-formation to obtain the lithium secondary battery anode.

Description

Preparation method of lithium secondary battery anode
Technical Field
The invention relates to a preparation method of a lithium secondary battery anode.
Background
Lithium ion batteries are considered to be a new type of power source that meets the increasing energy demands of portable electronic devices, electric and hybrid vehicles. Lithium ion batteries have been used in numerous civil and military applications, such as mobile phones, notebook computers, video cameras, digital cameras, and the like. In recent years, a plurality of environmental protection policies in China are released, the demand of new energy automobiles is rapidly increased, and the output of lithium batteries in China is improved. Data show that in 2018, the yield of lithium batteries in China reaches 139.9 hundred million, and is increased by 28.8 hundred million compared with 2017. The related data show that the yield of the Chinese lithium ion battery is 162383.3 thousands by 12 months in 2019, and the year-on-year increase is 9.4%. In the aspect of accumulation, the output of Chinese lithium ion batteries reaches 1572184.4 thousands in 2019 all the year round, and the increase is 4% on the same scale. And the performance of the positive electrode of the battery affects the performance of the battery.
Disclosure of Invention
The invention provides a preparation method of a lithium secondary battery anode, which comprises the steps of providing an active substance A and an active substance B, and sieving the active substance A to obtain a first active substance A and a second active substance A; sieving the active substance B to obtain a first active substance B and a second active substance B; the method comprises the steps of mixing a first active substance A and a second active substance B according to a preset proportion to obtain a first slurry, mixing the second active substance A and the first active substance B according to a preset proportion to obtain a second slurry, then sequentially coating the first slurry and the second slurry on a current collector for drying, and then placing a dried pole piece and a counter electrode into an electrolyte for pre-formation to obtain the lithium secondary battery anode.
The specific scheme is as follows:
a method of preparing a positive electrode for a lithium secondary battery, the method comprising:
1) providing an active material A and an active material B, wherein the average particle size of the active material A is 1.4-1.6 microns, and the average particle size of the active material B is 2.2-2.4 microns;
2) sieving the active substance A to obtain a first active substance A below the screen and a second active substance A on the screen; sieving the active substance B to obtain a first active substance B below the sieve and a second active substance B on the sieve, wherein the sieve pore size is 1.8-2 microns;
3) mixing a first active substance A and a second active substance B according to a predetermined mass ratio to obtain a first slurry, wherein the first active substance A/the second active substance B (mesh size-average particle size of active substance A)/(average particle size of active substance B-mesh size) is k 0.7-0.9;
4) mixing a second active substance A and a first active substance B according to a predetermined mass ratio to obtain a second slurry, wherein the second active substance A/the first active substance B is r (the average particle size of the active substance B-the pore size of the screen)/(the pore size of the screen-the average particle size of the active substance A), wherein r is 1.2-1.3;
5) sequentially coating the first slurry and the second slurry on a current collector and drying;
6) and placing the dried pole piece and the counter electrode in an electrolyte for preforming to obtain the lithium secondary battery anode, wherein the preforming step comprises constant current discharge to a discharge cut-off voltage by a first current, and then constant current discharge to a preset voltage lower than the discharge cut-off voltage by a second current, and the second current is lower than the first current.
Further, the active material A is LiNi0.1Mn0.85Mg0.05O2And the active material B is LiNi0.2Mn0.75Mg0.05O2。
Further, the ratio of the thickness of the first slurry coating layer to the thickness of the second slurry coating layer is 3:7-4: 6.
Further, the method for obtaining the slurry in the step 3 and the step 4 comprises the steps of sequentially adding the binder and the conductive agent into the solvent, then adding the active substance A and the active substance B, and uniformly mixing to obtain the slurry.
Further, the counter electrode is a lithium sheet.
Furthermore, the electrolyte comprises ethylene carbonate as an organic solvent and ethylene sulfite as an additive.
Further, the pre-formation comprises discharging to 2.75-2.77V with a current of 0.05-0.1C; then the discharge is continued to 2.71-2.72V with the current of 0.01-0.02C.
Further, a lithium secondary battery anode is prepared by the preparation method.
The invention has the following beneficial effects:
1) LiNi, active Material A0.1Mn0.85Mg0.05O2And the active material B LiNi0.2Mn0.75Mg0.05O2The mixing and matching of the first slurry and the second slurry can improve the cycle performance and rate performance of the positive electrode, wherein in the first slurry, the first active material A/the second active material B (k) (the sieve pore size-the average particle size of the active material A)/(the average particle size of the active material B-the sieve pore size), and k is 0.7-0.9; in the second slurry, the second active material a/first active material B ═ r (average particle size of active material B-mesh size)/(mesh size-average particle size of active material a), where r is from 1.2 to 1.3; the reason is that the active materials based on a specific particle size range are mixed according to the mass ratio of the relational expression of the present invention, and a more stable active material layer can be obtained, in which the average particle sizes of the two active materials are different, but after passing through the same sieve, the active material a having a small particle size and the active material B having a large particle size are mixed, and the active material B having a small particle size and the active material a having a large particle size are mixed, so that the particle size distributions of the two materials are balanced in the first and second slurries, and thus the obtained first and second layers have a relatively similar volume change rate, and the cycle stability of the electrode active material layer is improved.
2) The volume change rate of the first slurry layer is lower than that of the second slurry layer, so that the stress change of the active material layer is gradually reduced from the surface to the current collector, and the active material layer can be prevented from falling off from the surface of the current collector.
3) And the pre-formation process of the anode in the specific electrolyte loads excessive lithium ions on the anode, so that the energy density of the anode can be improved, and the excessive lithium ions can supplement the lithium ions lost by the SEI film, thereby improving the energy density of the lithium secondary battery.
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. In the present invention, the active material A is LiNi0.1Mn0.85Mg0.05O2And the active material B is LiNi0.2Mn0.75Mg0.05O2The solvent is NMP, the binder is PVDF, and the conductive agent is conductive carbon black.
Example 1
1) Providing an active material A and an active material B, wherein the average particle size of the active material A is 1.4 microns, and the average particle size of the active material B is 2.2 microns;
2) sieving the active substance A to obtain a first active substance A below the screen and a second active substance A on the screen; sieving the active substance B to obtain a first active substance B below the sieve and a second active substance B on the sieve, wherein the sieve pore size is 2 microns;
3) sequentially adding a binder and a conductive agent into a solvent, then adding a first active substance A and a second active substance B according to a preset mass ratio, and uniformly mixing to obtain a first slurry, wherein the mass ratio of the first active substance A to the second active substance B is 0.7 (2-1.4)/(2.2-2) to 2.1, and the mass ratio of the first active substance A to the second active substance B is the total mass of the active substances: adhesive: the conductive agent is 100:3: 4;
4) sequentially adding a binder and a conductive agent into a solvent, then adding a second active substance A and a first active substance B according to a preset mass ratio, and uniformly mixing to obtain a second slurry, wherein the mass ratio of the second active substance A to the first active substance B is 1.2 (2.2-2)/(2-1.4) and 0.4, and the mass ratio of the second active substance A to the first active substance B is the total amount of active substances: adhesive: the conductive agent is 100:3: 4;
5) sequentially coating the first slurry and the second slurry on a current collector and drying; wherein the ratio of the thickness of the first slurry coating layer to the thickness of the second slurry coating layer is 3:7, and the total thickness is 60 micrometers;
6) placing the dried pole piece and the dried counter electrode lithium piece into electrolyte for pre-formation to obtain the lithium secondary battery anode, wherein the solvent of the electrolyte is ethylene carbonate, 3 mass percent of ethylene sulfite and 1mol/L lithium hexafluorophosphate; the pre-formation comprises discharging to 2.75V at a current of 0.05C; then the discharge was continued to 2.71V at a current of 0.01C.
Example 2
1) Providing an active material A and an active material B, wherein the average particle size of the active material A is 1.6 micrometers, and the average particle size of the active material B is 2.4 micrometers;
2) sieving the active substance A to obtain a first active substance A below the screen and a second active substance A on the screen; sieving the active substance B to obtain a first active substance B below the sieve and a second active substance B on the sieve, wherein the sieve pore size is 1.8 microns;
3) sequentially adding a binder and a conductive agent into a solvent, then adding a first active substance A and a second active substance B according to a preset mass ratio, and uniformly mixing to obtain a first slurry, wherein the mass ratio of the first active substance A to the second active substance B is 0.9 (1.8-1.6)/(2.4-1.8) and 0.3, and the mass ratio of the first active substance A to the second active substance B is as follows: adhesive: the conductive agent is 100:3: 4;
4) sequentially adding a binder and a conductive agent into a solvent, then adding a second active substance A and a first active substance B according to a preset mass ratio, and uniformly mixing to obtain a second slurry, wherein the mass ratio of the second active substance A to the first active substance B is 1.3 (2.4-1.8)/(1.8-1.6) and 3.9, and the mass ratio of the second active substance A to the first active substance B is as follows: adhesive: the conductive agent is 100:3: 4;
5) sequentially coating the first slurry and the second slurry on a current collector and drying; wherein the ratio of the thickness of the first slurry coating layer to the thickness of the second slurry coating layer is 4:6, and the total thickness is 60 micrometers;
6) placing the dried pole piece and the dried counter electrode lithium piece into electrolyte for pre-formation to obtain the lithium secondary battery anode, wherein the solvent of the electrolyte is ethylene carbonate, 3 mass percent of ethylene sulfite and 1mol/L lithium hexafluorophosphate; the pre-formation comprises discharging to 2.77V at a current of 0.1C; then the discharge was continued to 2.72V at a current of 0.02C.
Example 3
1) Providing an active material A and an active material B, wherein the average particle size of the active material A is 1.5 micrometers, and the average particle size of the active material B is 2.3 micrometers;
2) sieving the active substance A to obtain a first active substance A below the screen and a second active substance A on the screen; sieving the active substance B to obtain a first active substance B below the sieve and a second active substance B on the sieve, wherein the sieve pore size is 1.9 microns;
3) sequentially adding a binder and a conductive agent into a solvent, then adding a first active substance A and a second active substance B according to a preset mass ratio, and uniformly mixing to obtain a first slurry, wherein the mass ratio of the first active substance A to the second active substance B is 0.8 (1.9-1.5)/(2.3-1.9) is 0.8, and the mass ratio of the first active substance A to the second active substance B is the total mass of the active substances: adhesive: the conductive agent is 100:3: 4;
4) sequentially adding a binder and a conductive agent into a solvent, then adding a second active substance A and a first active substance B according to a preset mass ratio, and uniformly mixing to obtain a second slurry, wherein the mass ratio of the second active substance A to the first active substance B is 1.2 (2.3-1.9)/(1.9-1.5) is 1.2, and the mass ratio of the second active substance A to the first active substance B is the total mass of the active substances: adhesive: the conductive agent is 100:3: 4;
5) sequentially coating the first slurry and the second slurry on a current collector and drying; wherein the ratio of the thickness of the first slurry coating layer to the thickness of the second slurry coating layer is 4:6, and the total thickness is 60 micrometers;
6) placing the dried pole piece and the dried counter electrode lithium piece into electrolyte for pre-formation to obtain the lithium secondary battery anode, wherein the solvent of the electrolyte is ethylene carbonate, 3 mass percent of ethylene sulfite and 1mol/L lithium hexafluorophosphate; the pre-formation includes discharging to 2.76V at a current of 0.06C; then the discharge was continued to 2.71V at a current of 0.01C.
Comparative example 1
1) Providing an active material A and an active material B, wherein the average particle size of the active material A is 1.5 micrometers, and the average particle size of the active material B is 2.3 micrometers;
2) sieving the active substance A to obtain a first active substance A below the screen and a second active substance A on the screen; sieving the active substance B to obtain a first active substance B below the sieve and a second active substance B on the sieve, wherein the sieve pore size is 1.9 microns;
3) sequentially adding a binder and a conductive agent into a solvent, then adding a first active substance A and a second active substance B according to a preset mass ratio, and uniformly mixing to obtain a first slurry, wherein the mass ratio of the first active substance A to the second active substance B is 1.2, and the mass ratio of the first active substance A to the second active substance B is the total mass of the active substances: adhesive: the conductive agent is 100:3: 4;
4) sequentially adding a binder and a conductive agent into a solvent, then adding a second active substance A and a first active substance B according to a preset mass ratio, and uniformly mixing to obtain a second slurry, wherein the mass ratio of the second active substance A to the first active substance B is 0.8, and the mass ratio of the second active substance A to the first active substance B is the total mass of the active substances: adhesive: the conductive agent is 100:3: 4;
5) sequentially coating the first slurry and the second slurry on a current collector and drying; wherein the ratio of the thickness of the first slurry coating layer to the thickness of the second slurry coating layer is 4:6, and the total thickness is 60 micrometers;
6) placing the dried pole piece and the dried counter electrode lithium piece into electrolyte for pre-formation to obtain the lithium secondary battery anode, wherein the solvent of the electrolyte is ethylene carbonate, 3 mass percent of ethylene sulfite and 1mol/L lithium hexafluorophosphate; the pre-formation includes discharging to 2.76V at a current of 0.06C; then the discharge was continued to 2.71V at a current of 0.01C.
Comparative example 2
1) Providing an active material A and an active material B, wherein the average particle size of the active material A is 1.5 micrometers, and the average particle size of the active material B is 2.3 micrometers;
2) sieving the active substance A to obtain a first active substance A below the screen and a second active substance A on the screen; sieving the active substance B to obtain a first active substance B below the sieve and a second active substance B on the sieve, wherein the sieve pore size is 1.9 microns;
3) sequentially adding a binder and a conductive agent into a solvent, then adding a first active substance A and a second active substance B according to a preset mass ratio, and uniformly mixing to obtain a first slurry, wherein the mass ratio of the first active substance A to the second active substance B is 0.5, and the mass ratio of the first active substance A to the second active substance B is the total mass of the active substances: adhesive: the conductive agent is 100:3: 4;
4) sequentially adding a binder and a conductive agent into a solvent, then adding a second active substance A and a first active substance B according to a preset mass ratio, and uniformly mixing to obtain a second slurry, wherein the mass ratio of the second active substance A to the first active substance B is 1.5, and the mass ratio of the second active substance A to the first active substance B is the total mass of the active substances: adhesive: the conductive agent is 100:3: 4;
5) sequentially coating the first slurry and the second slurry on a current collector and drying; wherein the ratio of the thickness of the first slurry coating layer to the thickness of the second slurry coating layer is 4:6, and the total thickness is 60 micrometers;
6) placing the dried pole piece and the dried counter electrode lithium piece into electrolyte for pre-formation to obtain the lithium secondary battery anode, wherein the solvent of the electrolyte is ethylene carbonate, 3 mass percent of ethylene sulfite and 1mol/L lithium hexafluorophosphate; the pre-formation includes discharging to 2.76V at a current of 0.06C; then the discharge was continued to 2.71V at a current of 0.01C.
Test and results
The first slurry and the second slurry of examples 1 to 3 and comparative examples 1 to 2 were tested, stored at room temperature for 10 hours, and the solid content at a position 5cm below the top of the slurry before and after storage was measured, and the solid content retention ratio calculated by the latter except the former was used to characterize the stability of the slurry, and then the positive electrode of examples 1 to 3 and comparative examples 1 to 2 and a lithium plate were used to constitute an experimental battery, and charge and discharge cycles were performed 300 times at a voltage interval of 2.7 to 4.2V under a current of 1C, and the retention ratio of the cycle capacity of the battery was measured, and the results are shown in table 1.
TABLE 1
The first size% The second size% Retention ratio of circulating Capacity (%)
Example 1 95.4 93.5 98.7
Example 2 94.6 93.2 98.5
Example 3 95.9 94.9 99.1
Comparative example 1 85.2 83.4 94.2
Comparative example 2 86.9 84.6 93.7
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. A method of preparing a positive electrode for a lithium secondary battery, the method comprising:
1) providing an active material A and an active material B, wherein the average particle size of the active material A is 1.4-1.6 microns, and the average particle size of the active material B is 2.2-2.4 microns;
2) sieving the active substance A to obtain a first active substance A below the screen and a second active substance A on the screen; sieving the active substance B to obtain a first active substance B below the sieve and a second active substance B on the sieve, wherein the sieve pore size is 1.8-2 microns;
3) mixing a first active substance A and a second active substance B according to a predetermined mass ratio to obtain a first slurry, wherein the first active substance A/the second active substance B (mesh size-average particle size of active substance A)/(average particle size of active substance B-mesh size) is k 0.7-0.9;
4) mixing a second active substance A and a first active substance B according to a predetermined mass ratio to obtain a second slurry, wherein the second active substance A/the first active substance B is r (the average particle size of the active substance B-the pore size of the screen)/(the pore size of the screen-the average particle size of the active substance A), wherein r is 1.2-1.3;
5) sequentially coating the first slurry and the second slurry on a current collector and drying;
6) and placing the dried pole piece and the counter electrode in an electrolyte for preforming to obtain the lithium secondary battery anode, wherein the preforming step comprises constant current discharge to a discharge cut-off voltage by a first current, and then constant current discharge to a preset voltage lower than the discharge cut-off voltage by a second current, and the second current is lower than the first current.
2. The method according to the above claim, wherein the active material A is LiNi0.1Mn0.85Mg0.05O2And the active material B is LiNi0.2Mn0.75Mg0.05O2。
3. The method of manufacturing according to the preceding claim, wherein the ratio of the thickness of the first slurry coating layer to the thickness of the second slurry coating layer is 3:7 to 4: 6.
4. The preparation method according to the above claim, wherein the step 3 and the step 4 are performed to obtain the slurry, and the method comprises adding the binder and the conductive agent to the solvent in sequence, then adding the active material A and the active material B, and uniformly mixing to obtain the slurry.
5. The method of claim, wherein the counter electrode is a lithium sheet.
6. The method according to the preceding claim, wherein the electrolyte solution comprises ethylene carbonate as an organic solvent and ethylene sulfite as an additive.
7. The method of claim, wherein the pre-forming comprises discharging to 2.75-2.77V at a current of 0.05-0.1C; then the discharge is continued to 2.71-2.72V with the current of 0.01-0.02C.
8. A lithium secondary battery positive electrode prepared by the preparation method of the above claim.
CN202010530192.2A 2020-06-11 2020-06-11 Preparation method of lithium secondary battery anode Withdrawn CN111710834A (en)

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* Cited by examiner, † Cited by third party
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CN112968157A (en) * 2021-02-06 2021-06-15 苏州精诚智造智能科技有限公司 Preparation method of power lithium ion battery

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112968157A (en) * 2021-02-06 2021-06-15 苏州精诚智造智能科技有限公司 Preparation method of power lithium ion battery
CN112968157B (en) * 2021-02-06 2022-11-01 苏州精诚智造智能科技有限公司 Preparation method of power lithium ion battery

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Application publication date: 20200925