CN106299351B - positive electrode slurry, preparation method thereof and lithium ion battery - Google Patents

positive electrode slurry, preparation method thereof and lithium ion battery Download PDF

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Publication number
CN106299351B
CN106299351B CN201610975920.4A CN201610975920A CN106299351B CN 106299351 B CN106299351 B CN 106299351B CN 201610975920 A CN201610975920 A CN 201610975920A CN 106299351 B CN106299351 B CN 106299351B
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revolution
rotation
speed
stirring
mixing
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CN106299351A (en
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王文华
钟宽
陈阳
李乾乾
李影
田静
吉纯
曾庆苑
段科
钟署亮
王晋
蒋世用
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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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
    • H01M4/48—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
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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 an anode slurry, which comprises 93-97.5 parts by weight of a lithium cobaltate material, 1.5-2.5 parts by weight of a conductive agent, 1.5-3 parts by weight of a binder, 0.1-0.5 part by weight of nano aluminum oxide and a solvent, wherein among various influence factors of a lithium ion battery, firstly, the nano Al 2 O 3 is added into the anode slurry according to the components and the proportion of the anode slurry, so that the heat insulation and the insulation effects can be effectively achieved, the safety performance of the battery is improved, a solid solution is formed by the lithium cobaltate and the nano Al 2 O 3, the crystal lattice can be stabilized, the rate capability and the cycle performance of the battery are improved, meanwhile, the nano Al 2 O 3 is coated on the lithium cobaltate, the thermal stability can be improved, the cycle capability and the overcharge resistance can be improved, the generation of oxygen and the decomposition of LiPF 6 can be inhibited, the contact between the lithium cobaltate and the electrolyte can be reduced, and the capacity loss can be reduced, so that the capacity is improved.

Description

Positive electrode slurry, preparation method thereof and lithium ion battery
Technical Field
the invention relates to the technical field of lithium ion battery materials, relates to a positive electrode slurry and a preparation method thereof, and a lithium ion battery, and particularly relates to a lithium cobaltate positive electrode slurry and a preparation method thereof, and a lithium ion battery.
Background
The lithium ion battery has the advantages of high working voltage, high specific energy, long cycle life, light weight, less white discharge, no memory effect, high cost performance and the like, and becomes a main selection object of rechargeable power supplies in the fields of high-power electric vehicles, artificial satellites, aerospace and the like. Therefore, lithium ion batteries and related materials thereof become research hotspots of researchers. The anode material is one of the key materials of the lithium ion battery and determines the performance of the lithium ion battery. The biggest bottleneck in limiting the energy density, power density, cycle life and safety of lithium ion power batteries is the positive electrode technology.
Lithium cobaltate (LiCoO 2) is used as a precursor of the anode material of the lithium ion battery, is a better anode material in the lithium ion battery, has the advantages of high working voltage, stable discharge, high specific energy, good cycle performance and the like, has excellent electrochemical performance, such as the average capacity attenuation of each cycle is less than 0.05 percent, the first discharge specific capacity is more than 135mAh/g, the ratio of a 3.6V primary discharge platform is more than 85 percent and the like, has excellent processing performance, such as large tap density, is beneficial to improving the volumetric specific capacity of the battery, has stable product performance, good consistency and the like, and therefore, the lithium cobaltate is suitable for large-flow discharge and the embedding and the separation of lithium ions and is used in the lithium ion battery with a high rate.
Lithium cobaltate batteries have good electrochemical performance and energy storage characteristics, are particularly important to be applied in the field of small consumer batteries, become the power source first choice of some portable electronic equipment, and are also the materials with the largest sales volume in lithium battery cathode materials due to the rapid development of consumer electronic product markets. Lithium cobaltate is moving towards high voltage, high compaction density in order to deliver higher capacity in smaller spaces.
However, in practical application, lithium cobaltate materials have two problems: (1) the structure of the lithium material is easily destroyed due to deep deintercalation. In the process of charging and discharging of the lithium ion battery, lithium ions are repeatedly inserted and extracted in positive and negative electrode materials, so that the structure of the commonly adopted positive electrode active material lithium cobaltate is changed after multiple times of shrinkage and expansion, and the lithium cobaltate is loosened and falls off among layers, so that the internal resistance is increased, and the specific capacity of electrochemistry is reduced. (2) The high oxidation potential of the positive electrode surface accelerates the decomposition of the electrolyte. The high voltage can extract more lithium ions from the crystal structure, so that the capacity of the battery is increased, but the cycle performance and the safety performance of the battery are affected by the large extraction of lithium due to the structural damage. Particularly, under the condition of high-voltage charge and discharge, the cycle performance of lithium cobaltate is deteriorated, and the main reason for quick capacity attenuation is that the structure is unstable due to phase change of a material in a high lithium removal state and oxygen loss of crystal lattices; the material reacts with the electrolyte to cause the dissolution of cobalt and the like.
At present, the defects of poor cycle performance, poor stability and the like of the lithium cobaltate battery increasingly limit the lithium cobaltate material and overcome the defects, and the lithium cobaltate battery becomes one of the focuses of wide attention of a plurality of development type production enterprises in the industry.
disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a positive electrode slurry, a preparation method thereof, and a lithium ion battery, wherein the lithium cobalt oxide battery containing the positive electrode slurry prepared by the present invention has better cycle performance and stability.
The invention provides a positive electrode slurry, which comprises:
a solvent.
Preferably, the conductive agent comprises one or more of conductive carbon black, conductive graphite, graphene, acetylene black, ketjen black, carbon fiber, carbon nanotube and Super P;
The binder comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride and styrene-butadiene latex;
the solvent comprises one or more of N-methyl pyrrolidone, dimethyl acetamide, acetone and N, N-dimethylformamide;
the solid content of the anode slurry is 50-75%.
Preferably, the positive electrode slurry includes:
94-96.5 parts by weight of a lithium cobaltate material;
1.7-2.3 parts by weight of KS-6 and Super P;
1.8-2.5 parts by weight of PVDF;
0.3-0.5 parts by weight of nano aluminum oxide.
The invention provides a preparation method of anode slurry, which comprises the following steps:
A) Stirring and mixing the binder and the solvent through rotation and revolution to obtain a sizing material;
B) And (3) carrying out second rotation, revolution, stirring and mixing on the conductive agent, the nano aluminum oxide and the solvent, and then adding the sizing material prepared in the step and the lithium cobaltate material to carry out third rotation, revolution, stirring and mixing to obtain the anode slurry.
Preferably, the step a) is specifically:
A1) Firstly, carrying out rotation, revolution and stirring mixing on 60-70% of a binder and a solvent to obtain a section of mixture;
A2) And (3) performing rotation, revolution and stirring mixing on the mixture obtained in the step and 30% -40% of the binder again to obtain the sizing material.
Preferably, the step a1) is specifically:
Stirring and mixing 60-70% of binder and solvent under the conditions of first rotation and revolution, second rotation and revolution and third rotation and revolution respectively to obtain a section of mixture;
The step A2) is specifically as follows:
and adding 30-40% of binder into the mixture obtained in the step, and stirring and mixing under the conditions of the fourth rotation and revolution, the fifth rotation and revolution and the sixth rotation and revolution respectively to obtain the sizing material.
preferably, the revolution speed of the first rotation revolution is 5-15 r/min; the rotation speed of the first rotation revolution is 500-800 r/min; the time of the first rotation and revolution is 10-20 min;
The revolution speed of the second rotation revolution is 15-25 r/min; the rotation speed of the second rotation revolution is 1200-1500 r/min; the second rotation and revolution time is 20-30 min;
The revolution speed of the third rotation revolution is 25-35 r/min; the rotation speed of the third rotation revolution is 2000-2500 r/min; the time of the third rotation and revolution is 60-100 min;
The revolution speed of the fourth revolution is 5-15 r/min; the rotation speed of the fourth revolution is 500-800 r/min; the time of the fourth revolution is 10-20 min;
The revolution speed of the fifth rotation revolution is 15-25 r/min; the rotation speed of the fifth rotation revolution is 1200-1500 r/min; the time of the fifth rotation and revolution is 20-30 min;
the revolution speed of the sixth rotation revolution is 25-35 r/min; the rotation speed of the sixth rotation revolution is 2000-2500 r/min; the time of the sixth rotation and revolution is 120-150 min;
the third rotation and revolution is carried out under the vacuum condition; the sixth rotation and revolution is performed under vacuum conditions.
Preferably, the step B) is specifically:
B1) Respectively stirring and mixing the conductive agent, the nano aluminum oxide and the solvent under the conditions of seventh rotation and revolution and eighth rotation and revolution to obtain a premix;
The revolution speed of the seventh rotation revolution is 15-25 r/min; the rotation speed of the seventh rotation revolution is 500-800 r/min; the time of the seventh rotation and revolution is 10-20 min;
the revolution speed of the eighth rotation revolution is 20-30 r/min; the rotation speed of the eighth rotation revolution is 800-1500 r/min; the eighth rotation and revolution time is 30-50 min;
The eighth rotation and revolution is carried out under the vacuum condition;
B2) and (3) carrying out third rotation revolution stirring and mixing on the pre-mixture, the sizing material and the lithium cobaltate material to obtain the anode slurry.
preferably, the step B2) is specifically:
respectively stirring and mixing the pre-mixture and 30-40% of sizing material under the conditions of ninth rotation and revolution and tenth rotation and revolution to obtain a primary mixture;
Then adding 53-61% of lithium cobaltate material into the intermediate mixture obtained in the step, stirring and mixing under the eleventh rotation and revolution condition, adding 24-33% of lithium cobaltate material, stirring and mixing under the twelfth rotation and revolution condition, adding 10-18% of lithium cobaltate material, stirring and mixing under the thirteenth rotation and revolution condition and the fourteenth rotation and revolution condition respectively, and obtaining an intermediate mixture;
Finally, 60-70% of sizing material is added into the intermediate mixture obtained in the step, and the mixture is stirred and mixed under the conditions of the fifteenth rotation and revolution, the sixteenth rotation and revolution, the seventeenth rotation and revolution and the eighteenth rotation and revolution respectively to obtain anode slurry;
the revolution speed of the ninth rotation revolution is 15-25 r/min; the rotation speed of the ninth rotation revolution is 500-800 r/min; the ninth rotation and revolution time is 5-10 min;
The revolution speed of the tenth rotation revolution is 25-35 r/min; the rotation speed of the tenth rotation revolution is 2000-2500 r/min; the time of the tenth rotation and revolution is 30-60 min;
the revolution speed of the eleventh rotation revolution is 15-25 r/min; the rotation speed of the eleventh rotation revolution is 800-1000 r/min; the eleventh rotation and revolution time is 5-10 min;
The revolution speed of the twelfth autorotation revolution is 10-20 r/min; the rotation speed of the twelfth rotation revolution is 800-1000 r/min; the time of the twelfth autorotation and revolution is 5-10 min;
the revolution speed of the thirteenth rotation revolution is 10-20 r/min; the rotation speed of the thirteenth rotation revolution is 800-1000 r/min; the time of the thirteenth rotation revolution is 5-10 min;
the revolution speed of the fourteenth autorotation revolution is 15-25 r/min; the rotation speed of the fourteenth rotation revolution is 1800-2000 r/min; the fourteenth autorotation and revolution time is 60-90 min;
the revolution speed of the fifteenth rotation revolution is 10-20 r/min; the rotation speed of the fifteenth rotation revolution is 800-1000 r/min; the time of the fifteenth rotation and revolution is 5-10 min;
the revolution speed of the sixteenth rotation revolution is 20-30 r/min; the rotation speed of the sixteenth rotation revolution is 1500-2000 r/min; the sixteenth rotation and revolution time is 5-10 min;
The revolution speed of the seventeenth rotation revolution is 25-35 r/min; the rotation speed of the seventeenth rotation revolution is 2000-2500 r/min; the seventeenth rotation and revolution time is 120-150 min;
the revolution speed of the eighteenth rotation revolution is 15-25 r/min; the rotation speed of the eighteenth rotation revolution is 1500-2000 r/min; the eighteenth rotation and revolution time is 5-10 min;
The tenth rotation and revolution is carried out under the vacuum condition; the fourteenth autorotation and revolution is carried out under the vacuum condition; the sixteenth rotation and revolution is carried out under the vacuum condition; the seventeenth rotation and revolution is carried out under the vacuum condition; the eighteenth rotation and revolution is performed under vacuum conditions.
The invention provides a lithium ion battery, which comprises an anode;
the positive electrode is coated with the positive electrode slurry according to any one of the above technical schemes or the positive electrode slurry prepared according to any one of the above technical schemes.
2 3 2 3 2 3 6The invention provides an anode slurry, which comprises 93-97.5 parts by weight of a lithium cobaltate material, 1.5-2.5 parts by weight of a conductive agent, 1.5-3 parts by weight of a binder, 0.1-0.5 part by weight of nano aluminum oxide and a solvent, compared with the prior art, the anode slurry disclosed by the invention has the defects that the structure of a deeply-embedded lithium cobaltate material is easy to damage, the decomposition of an electrolyte is accelerated by a high oxidation potential on the surface of an anode, so that the internal resistance is increased, the electrochemical specific capacity is reduced, the cycle performance is poor and the structural stability is poor.
Detailed Description
For a further understanding of the invention, preferred embodiments of the invention are described below in conjunction with the examples, but it should be understood that these descriptions are included merely to further illustrate the features and advantages of the invention and are not intended to limit the invention to the claims.
all of the starting materials of the present invention, without particular limitation as to their source, may be purchased commercially or prepared according to conventional methods well known to those skilled in the art.
all the raw materials of the invention are not particularly limited in purity, and the invention preferably adopts the purity commonly used in the field of analytical pure lithium ion batteries.
The invention provides a positive electrode slurry, which comprises:
a solvent.
The lithium cobaltate material is not particularly limited in the present invention, and can be selected and adjusted by those skilled in the art according to actual production conditions, quality requirements and product performance. In order to further optimize the slurry composition and improve the performance of the product, the content of the lithium cobaltate material in the positive electrode slurry is preferably 93-97.5 parts by weight, more preferably 94-96.5 parts by weight, most preferably 95-95.5 parts by weight, and particularly 96.5 parts by weight.
the conductive agent is not particularly limited, and may be a conductive agent known to those skilled in the art, and those skilled in the art may select and adjust the conductive agent according to actual production conditions, quality requirements, and product properties, and the conductive agent of the present invention preferably includes one or more of conductive carbon black, conductive graphite, graphene, acetylene black, ketjen black, carbon nanotube, or Super P, more preferably two or more of conductive carbon black, KS-6, acetylene black, carbon fiber, carbon nanotube, and Super P, and the present invention selects conductive agents with different morphologies based on the difference in morphology of the conductive agent to form a conductive network structure, which has better effect compared with a linear or granular conductive structure, most preferred for use herein are KS-6 and Super P. In order to further optimize the slurry composition and improve the performance of the product, the content of the conductive agent in the positive electrode slurry is preferably 1.7-2.3 parts by weight, more preferably 1.8-2.2 parts by weight, most preferably 1.9-2.1 parts by weight, and particularly may be 2.0 parts by weight.
the binder is not particularly limited in the present invention, and may be a binder known to those skilled in the art, and those skilled in the art can select and adjust the binder according to actual production conditions, quality requirements and product performance, and the binder of the present invention preferably includes one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene, polyvinylidene fluoride and styrene-butadiene latex, more preferably PVDF, polytetrafluoroethylene, polyvinylidene fluoride or styrene-butadiene latex, and most preferably PVDF. In order to further optimize the slurry composition and improve the performance of the product, the content of the binder in the positive electrode slurry is preferably 1.5-3 parts by weight, more preferably 1.7-2.7 parts by weight, most preferably 2.0-2.5 parts by weight, and particularly 1.8 parts by weight.
The nano-alumina is not particularly limited by the invention, so that the nano-alumina can be selected and adjusted by the technicians in the field according to the actual production condition, the quality requirement and the product performance. In order to further optimize the slurry composition and improve the performance of the product, the content of the nano aluminum oxide in the positive electrode slurry is preferably 0.1-0.5 part by weight, more preferably 0.2-0.4 part by weight, most preferably 0.25-0.35 part by weight, and particularly may be 0.3 part by weight.
The solvent is not particularly limited in the present invention, and may be selected and adjusted by those skilled in the art according to the actual production situation, quality requirements and product properties, and the solvent of the present invention preferably includes one or more of N-methylpyrrolidone (NMP), dimethylacetamide, acetone and N, N-dimethylformamide, more preferably NMP, dimethylacetamide, acetone or N, N-dimethylformamide, and most preferably NMP. In order to further optimize the slurry composition and improve the performance of the product, the lithium cobaltate material, the conductive agent, the binder and the aluminum oxide in the positive electrode slurry are solutes, and the solid content of the positive electrode slurry is preferably 50-75%, more preferably 55-70%, and most preferably 60-65%.
The invention also provides a preparation method of the anode slurry, which comprises the following steps:
A) stirring and mixing the binder and the solvent through rotation and revolution to obtain a sizing material;
B) And (3) carrying out second rotation, revolution, stirring and mixing on the conductive agent, the nano aluminum oxide and the solvent, and then adding the sizing material prepared in the step and the lithium cobaltate material to carry out third rotation, revolution, stirring and mixing to obtain the anode slurry.
In the present invention, the preferred principles of the selection and the proportion of the raw materials, etc., are consistent with the preferred principles of the selection and the proportion of the raw materials of the positive electrode slurry, etc., if no special reference is made, and are not described in detail herein.
Firstly, the adhesive and the solvent are stirred and mixed by rotation and revolution to obtain the sizing material.
The present invention is not particularly limited to the above-mentioned stirring and mixing device, and may be a mixing device having a stirring function of rotation and revolution, which is well known to those skilled in the art. The specific conditions of the rotation and revolution are not particularly limited, and the conventional conditions of the rotation and revolution known by the technical personnel in the field can be used, and the technical personnel in the field can select and adjust the conditions according to the actual production condition, the quality requirement and the product performance, and the revolution speed of the rotation and revolution is preferably 5-35 r/min, more preferably 10-30 r/min, and most preferably 15-25 r/min; the rotation revolution speed of the rotation and revolution is preferably 500-2500 r/min, more preferably 1000-2000 r/min, and most preferably 1200-1800 r/min; the rotation and revolution time is preferably 240-350 min, more preferably 260-330 min, and most preferably 280-310 min. The addition amount of the solvent is not particularly limited in the present invention, and the solvent addition amount known to those skilled in the art can be selected and adjusted by those skilled in the art according to the actual production situation, quality requirements and product performance, and the addition amount of the solvent in the present invention is preferably 9 to 11 times, more preferably 9.5 to 10.5 times, and most preferably 10 times of that of the binder.
the invention aims at the problems existing in the performance of the lithium cobalt oxide battery, starts from the glue making process of battery pulping, improves the dispersion uniformity in the pulping process, improves the process control, improves the stability and uniformity of the battery pulping process, and further improves the electrochemical performance of the lithium cobalt oxide battery.
The invention firstly changes the feeding sequence and the feeding proportion, and the step A) is particularly preferably as follows:
A1) Firstly, carrying out rotation, revolution and stirring mixing on 60-70% of a binder and a solvent to obtain a section of mixture;
A2) And (3) performing rotation, revolution and stirring mixing on the mixture obtained in the step and 30% -40% of the binder again to obtain the sizing material.
the 60-70% of the binder in the invention refers to 60-70%, more preferably 62-68%, most preferably 64-66% of the total amount of the binder required to be added into the slurry, and specifically can be 2/3; the 30% to 40% of the binder refers to the total amount of the binder required to be added into the slurry, and the rest is, more preferably, 32% to 38%, most preferably 34% to 36%, and particularly 1/3%, except the amount added in the step A1).
the specific conditions for the rotation-revolution stirring and mixing are not particularly limited, and the conventional conditions for rotation and revolution well known by the technicians in the field can be used, and the technicians in the field can select and adjust the conditions according to the actual production condition, quality requirements and product performance, and the revolution speed for the rotation-revolution stirring and mixing is preferably 5-35 r/min, more preferably 10-30 r/min, and most preferably 15-25 r/min; the rotation speed of the rotation, revolution and stirring mixing is preferably 500-2500 r/min, more preferably 1000-2000 r/min, and most preferably 1200-1800 r/min; the time for firstly carrying out rotation and revolution stirring and mixing is preferably 90-150 min, more preferably 100-140 min, and most preferably 110-130 min.
The specific conditions for the secondary rotation, revolution, stirring and mixing are not particularly limited, and the conventional conditions for rotation and revolution well known by the technicians in the field can be used, and the technicians in the field can select and adjust the conditions according to the actual production condition, quality requirements and product performance, and the revolution speed for the secondary rotation, revolution, stirring and mixing is preferably 5-35 r/min, more preferably 10-30 r/min, and most preferably 15-25 r/min; the rotation speed for performing rotation, revolution, stirring and mixing again is preferably 500-2500 r/min, more preferably 1000-2000 r/min, and most preferably 1200-1800 r/min; the time for stirring and mixing the mixture by rotation and revolution again is preferably 150-200 min, more preferably 160-190 min, and most preferably 170-180 min.
the invention optimizes the rotation speed, time and revolution and rotation collocation in the rotation and revolution stirring and mixing process again, and improves the uniformity and dispersion degree of the slurry, the step A1) is particularly preferred, 60-70% of the binder and the solvent are stirred and mixed under the conditions of first rotation and revolution, second rotation and revolution and third rotation and revolution respectively, and a section of mixture is obtained;
The step A2) is specifically preferably to add 30-40% of binder into the mixture obtained in the step A, and to stir and mix the mixture respectively under the conditions of the fourth revolution, the fifth revolution and the sixth revolution to obtain the sizing material.
the specific conditions of the first rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the conditions according to actual production conditions, quality requirements and product performance, wherein the revolution speed of the first rotation and revolution is preferably 5-15 r/min, more preferably 7-13 r/min, and most preferably 9-11 r/min; the rotation speed of the first rotation revolution is preferably 500-800 r/min, more preferably 550-750 r/min, and most preferably 600-700 r/min; the time of the first rotation and revolution is preferably 10-20 min, more preferably 12-18 min, and most preferably 14-16 min.
The specific conditions of the second rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the second rotation and revolution according to the actual production condition, the quality requirement and the product performance, wherein the revolution speed of the second rotation and revolution is preferably 15-25 r/min, more preferably 17-23 r/min, and most preferably 19-21 r/min; the rotation speed of the second rotation revolution is preferably 1200-1500 r/min, more preferably 1250-1450 r/min, and most preferably 1300-1400 r/min; the time of the second rotation and revolution is preferably 20-30 min, more preferably 22-28 min, and most preferably 24-26 min.
the specific conditions of the third rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the conditions according to actual production conditions, quality requirements and product performance, wherein the revolution speed of the third rotation and revolution is preferably 25-35 r/min, more preferably 27-33 r/min, and most preferably 29-31 r/min; the rotation speed of the third rotation revolution is preferably 2000-2500 r/min, more preferably 2100-2400 r/min, and most preferably 2200-2300 r/min; the time of the third rotation and revolution is preferably 60 to 100min, more preferably 70 to 90min, and most preferably 75 to 85 min. The third rotation and revolution of the present invention is preferably performed under vacuum conditions; the specific vacuum pressure of the vacuum is not particularly limited in the present invention, and may be a conventional vacuum pressure well known to those skilled in the art, and those skilled in the art can select and adjust the vacuum pressure according to actual production conditions, quality requirements and product performance.
The specific conditions of the fourth revolution are not particularly limited, and a person skilled in the art can select and adjust the revolution speed according to the actual production condition, the quality requirement and the product performance, wherein the revolution speed of the fourth revolution is preferably 5-15 r/min, more preferably 7-13 r/min, and most preferably 9-11 r/min; the rotation speed of the fourth revolution is preferably 500-800 r/min, more preferably 550-750 r/min, and most preferably 600-700 r/min; the time of the fourth revolution is preferably 10-20 min, more preferably 12-18 min, and most preferably 14-16 min.
The specific conditions of the fifth rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the conditions according to actual production conditions, quality requirements and product performance, wherein the revolution speed of the fifth rotation and revolution is preferably 15-25 r/min, more preferably 17-23 r/min, and most preferably 19-21 r/min; the rotation speed of the fifth rotation revolution is preferably 1200-1500 r/min, more preferably 1250-1450 r/min, and most preferably 1300-1400 r/min; the time of the fifth rotation and revolution is preferably 20-30 min, more preferably 22-28 min, and most preferably 24-26 min.
the specific conditions of the sixth rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the conditions according to actual production conditions, quality requirements and product performance, wherein the revolution speed of the sixth rotation and revolution is preferably 25-35 r/min, more preferably 27-33 r/min, and most preferably 29-31 r/min; the rotation speed of the sixth rotation revolution is preferably 2000-2500 r/min, more preferably 2100-2400 r/min, and most preferably 2200-2300 r/min; the time of the sixth rotation and revolution is preferably 120 to 150min, more preferably 125 to 145min, and most preferably 130 to 140 min. The sixth rotation and revolution of the present invention is preferably performed under vacuum conditions; the specific vacuum pressure of the vacuum is not particularly limited in the present invention, and may be a conventional vacuum pressure well known to those skilled in the art, and those skilled in the art can select and adjust the vacuum pressure according to actual production conditions, quality requirements and product performance.
The specific process of step a) of the present invention can also preferably refer to table 1, where table 1 is a flow chart of the glue making process provided by the present invention.
TABLE 1 flow chart of the glue making process provided by the present invention
Preparing rubber according to the content of PVDF in rubber material being 10 percent
the PVDF was weighed to a mass of 1.2m, taking into account the process losses, and a mass of 10.8m, requiring NMP
according to the invention, the sizing material is prepared through the steps, then the conductive agent, the nano aluminum oxide and the solvent are stirred and mixed for the second rotation and revolution, and then the sizing material prepared through the steps and the lithium cobaltate material are added for the third rotation and revolution, and stirring and mixing are carried out, so that the anode slurry is obtained.
the addition amount of the solvent is not particularly limited in the present invention, and can be selected and adjusted by those skilled in the art according to the actual production situation, quality requirement and product performance. Aiming at the problems existing in the performance of the lithium cobaltate battery, the invention starts from the material stirring process of battery pulping, changes the feeding sequence and the feeding proportion, improves the dispersion uniformity in the pulping process, improves the process control, improves the stability and uniformity of the battery pulping process, and further improves the electrochemical performance of the lithium cobaltate battery.
the specific conditions for stirring and mixing the second rotation and revolution are not particularly limited, and the conventional conditions for rotation and revolution well known by the technicians in the field can be used, and the technicians in the field can select and adjust the conditions according to the actual production condition, quality requirements and product performance, wherein the revolution speed for stirring and mixing the second rotation and revolution is preferably 15-30 r/min, more preferably 18-27 r/min, and most preferably 21-24 r/min; the rotation speed of the second rotation and revolution stirring and mixing is preferably 500-1500 r/min, more preferably 700-1300 r/min, and most preferably 900-1100 r/min; the time for firstly carrying out rotation and revolution stirring and mixing is preferably 40-70 min, more preferably 45-65 min, and most preferably 50-60 min.
The specific conditions for the third rotation, revolution, stirring and mixing are not particularly limited, and the conventional conditions for rotation and revolution well known to those skilled in the art can be used, and those skilled in the art can select and adjust the conditions according to actual production conditions, quality requirements and product performance, and the revolution speed for the third rotation, revolution, stirring and mixing is preferably 10-35 r/min, more preferably 15-30 r/min, and most preferably 20-25 r/min; the rotation speed of the third rotation, revolution, stirring and mixing is preferably 800-2500 r/min, more preferably 1200-2200 r/min, and most preferably 1500-2000 r/min; the time for stirring and mixing the third rotation and revolution is preferably 245-370 min, more preferably 265-350 min, and most preferably 290-330 min.
The invention changes the feeding sequence and the feeding proportion, optimizes the rotation speed, time and revolution and rotation collocation in the rotation, revolution and stirring and mixing process, and improves the uniformity and dispersity of the slurry, wherein the step B) is particularly preferably as follows:
B1) Respectively stirring and mixing the conductive agent, the nano aluminum oxide and the solvent under the conditions of seventh rotation and revolution and eighth rotation and revolution to obtain a premix;
B2) Respectively stirring and mixing the pre-mixture and 30-40% of sizing material under the conditions of ninth rotation and revolution and tenth rotation and revolution to obtain a primary mixture;
then adding 53-61% of lithium cobaltate material into the intermediate mixture obtained in the step, stirring and mixing under the eleventh rotation and revolution condition, adding 24-33% of lithium cobaltate material, stirring and mixing under the twelfth rotation and revolution condition, adding 10-18% of lithium cobaltate material, stirring and mixing under the thirteenth rotation and revolution condition and the fourteenth rotation and revolution condition respectively, and obtaining an intermediate mixture;
and finally, adding 60-70% of sizing material into the intermediate mixture obtained in the step, and stirring and mixing under the conditions of a fifteenth rotation and revolution, a sixteenth rotation and revolution, a seventeenth rotation and revolution and an eighteenth rotation and revolution respectively to obtain the anode slurry.
The 30-40% of the sizing material is 30-40% of the total amount of the sizing material obtained by the step, which is required to be added into the sizing material, more preferably 32-38%, most preferably 34-36%, and particularly 1/3; the 60% to 70% of the size, i.e. the total amount of the size obtained by the above steps, which is required to be added into the size, is the rest part except the amount added in the previous step, more preferably 62% to 68%, most preferably 64% to 66%, and particularly 2/3.
as defined above, 53% to 61% of the lithium cobaltate material according to the present invention, more preferably 54% to 60%, more preferably 55% to 59%, most preferably 56% to 58%, and specifically 4/7; the 24% to 33% of the lithium cobaltate material is more preferably 25% to 32%, more preferably 26% to 31%, most preferably 27% to 30%, and specifically can be 2/7; the 10% to 18% lithium cobaltate material may be 1/7, more preferably 11% to 17%, more preferably 12% to 16%, most preferably 13% to 15%.
The specific conditions of the seventh rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the conditions according to actual production conditions, quality requirements and product performance, wherein the revolution speed of the seventh rotation and revolution is preferably 15-25 r/min, more preferably 17-23 r/min, and most preferably 19-21 r/min; the rotation speed of the seventh rotation revolution is preferably 500-800 r/min, more preferably 550-750 r/min, and most preferably 600-700 r/min; the time of the seventh rotation and revolution is preferably 10-20 min, more preferably 12-18 min, and most preferably 14-16 min.
The specific conditions of the eighth rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the conditions according to actual production conditions, quality requirements and product performance, wherein the revolution speed of the eighth rotation and revolution is preferably 20-30 r/min, more preferably 22-28 r/min, and most preferably 24-26 r/min; the rotation speed of the eighth rotation revolution is preferably 800-1500 r/min, more preferably 900-1400 r/min, and most preferably 1000-1300 r/min; the time of the eighth rotation and revolution is preferably 30 to 50min, more preferably 35 to 45min, and most preferably 37 to 43 min. The eighth rotation and revolution of the present invention is preferably performed under vacuum conditions; the specific vacuum pressure of the vacuum is not particularly limited in the present invention, and may be a conventional vacuum pressure well known to those skilled in the art, and those skilled in the art can select and adjust the vacuum pressure according to actual production conditions, quality requirements and product performance.
The specific conditions of the ninth rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the conditions according to actual production conditions, quality requirements and product performance, and the revolution speed of the ninth rotation and revolution is preferably 15-25 r/min, more preferably 17-23 r/min, and most preferably 19-21 r/min; the rotation speed of the ninth rotation revolution is preferably 500-800 r/min, more preferably 550-750 r/min, and most preferably 600-700 r/min; the time of the ninth rotation and revolution is preferably 5 to 10min, more preferably 6 to 9min, and most preferably 7 to 8 min.
The specific conditions of the tenth rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the conditions according to actual production conditions, quality requirements and product performance, wherein the revolution speed of the tenth rotation and revolution is preferably 25-35 r/min, more preferably 27-33 r/min, and most preferably 29-31 r/min; the rotation speed of the tenth rotation revolution is preferably 2000-2500 r/min, more preferably 2100-2400 r/min, and most preferably 2200-2300 r/min; the time of the tenth rotation and revolution is preferably 30 to 60min, more preferably 35 to 55min, and most preferably 40 to 50 min. The tenth rotation and revolution of the present invention is preferably performed under vacuum conditions; the specific vacuum pressure of the vacuum is not particularly limited in the present invention, and may be a conventional vacuum pressure well known to those skilled in the art, and those skilled in the art can select and adjust the vacuum pressure according to actual production conditions, quality requirements and product performance.
The specific conditions of the eleventh rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the specific conditions according to actual production conditions, quality requirements and product performance, wherein the revolution speed of the eleventh rotation and revolution is preferably 15-25 r/min, more preferably 17-23 r/min, and most preferably 19-21 r/min; the rotation speed of the eleventh rotation revolution is preferably 800-1000 r/min, more preferably 830-970 r/min, and most preferably 850-950 r/min; the time of the eleventh rotation and revolution is preferably 5 to 10min, more preferably 6 to 9min, and most preferably 7 to 8 min.
the specific conditions of the twelfth rotation revolution are not particularly limited, and a person skilled in the art can select and adjust the specific conditions according to actual production conditions, quality requirements and product performance, wherein the revolution speed of the twelfth rotation revolution is preferably 10-20 r/min, more preferably 12-18 r/min, and most preferably 14-16 r/min; the rotation speed of the twelfth rotation revolution is preferably 800-1000 r/min, more preferably 830-970 r/min, and most preferably 850-950 r/min; the time of the twelfth rotation and revolution is preferably 5-10 min, more preferably 6-9 min, and most preferably 7-8 min.
the specific conditions of the thirteenth rotation revolution are not particularly limited, and a person skilled in the art can select and adjust the revolution speed according to the actual production condition, the quality requirement and the product performance, wherein the revolution speed of the thirteenth rotation revolution is preferably 10-20 r/min, more preferably 12-18 r/min, and most preferably 14-16 r/min; the rotation speed of the thirteenth rotation revolution is preferably 800-1000 r/min, more preferably 830-970 r/min, and most preferably 850-950 r/min; the time of the thirteenth rotation revolution is preferably 5-10 min, more preferably 6-9 min, and most preferably 7-8 min.
The specific conditions of the fourteenth rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the conditions according to actual production conditions, quality requirements and product performance, and the revolution speed of the fourteenth rotation and revolution is preferably 15-25 r/min, more preferably 17-23 r/min, and most preferably 19-21 r/min; the rotation speed of the fourteenth rotation revolution is preferably 1800-2000 r/min, more preferably 1850-1950 r/min, and most preferably 1870-1930 r/min; the time of the fourteenth rotation and revolution is preferably 60 to 90min, more preferably 75 to 85min, and most preferably 70 to 80 min. The fourteenth rotation and revolution of the present invention is preferably performed under vacuum conditions; the specific vacuum pressure of the vacuum is not particularly limited in the present invention, and may be a conventional vacuum pressure well known to those skilled in the art, and those skilled in the art can select and adjust the vacuum pressure according to actual production conditions, quality requirements and product performance.
The specific conditions of the fifteenth rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the fifteenth rotation and revolution according to the actual production condition, the quality requirement and the product performance, wherein the revolution speed of the fifteenth rotation and revolution is preferably 10-20 r/min, more preferably 12-18 r/min, and most preferably 14-16 r/min; the rotation speed of the fifteenth rotation revolution is preferably 800-1000 r/min, more preferably 830-970 r/min, and most preferably 850-950 r/min; the time of the fifteenth rotation and revolution is preferably 5-10 min, more preferably 6-9 min, and most preferably 7-8 min.
The specific conditions of the sixteenth rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the conditions according to actual production conditions, quality requirements and product performance, wherein the revolution speed of the sixteenth rotation and revolution is preferably 20-30 r/min, more preferably 22-28 r/min, and most preferably 24-26 r/min; the rotation speed of the sixteenth rotation revolution is preferably 1500-2000 r/min, more preferably 1600-1900 r/min, and most preferably 1700-1800 r/min; the time of the sixteenth rotation and revolution is preferably 5-10 min, more preferably 6-9 min, and most preferably 7-8 min. The sixteenth rotation and revolution of the present invention is preferably performed under vacuum conditions; the specific vacuum pressure of the vacuum is not particularly limited in the present invention, and may be a conventional vacuum pressure well known to those skilled in the art, and those skilled in the art can select and adjust the vacuum pressure according to actual production conditions, quality requirements and product performance.
the specific conditions of the seventeenth rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the revolution speed according to the actual production condition, the quality requirement and the product performance, wherein the revolution speed of the seventeenth rotation and revolution is preferably 25-35 r/min, more preferably 27-33 r/min, and most preferably 29-31 r/min; the rotation speed of the seventeenth rotation revolution is preferably 2000-2500 r/min, more preferably 2100-2400 r/min, and most preferably 2200-2300 r/min; the time of the seventeenth rotation and revolution is preferably 120-150 min, more preferably 125-145 min, and most preferably 130-140 min. The seventeenth rotation and revolution of the present invention is preferably performed under vacuum; the specific vacuum pressure of the vacuum is not particularly limited in the present invention, and may be a conventional vacuum pressure well known to those skilled in the art, and those skilled in the art can select and adjust the vacuum pressure according to actual production conditions, quality requirements and product performance.
the specific conditions of the eighteenth rotation and revolution are not particularly limited, and a person skilled in the art can select and adjust the conditions according to actual production conditions, quality requirements and product performance, and the revolution speed of the eighteenth rotation and revolution is preferably 15-25 r/min, more preferably 17-23 r/min, and most preferably 19-21 r/min; the rotation speed of the eighteenth rotation revolution is preferably 1500-2000 r/min, more preferably 1600-1900 r/min, and most preferably 1700-1800 r/min; the time of the eighteenth rotation and revolution is preferably 5-10 min, more preferably 6-9 min, and most preferably 7-8 min. The eighteenth rotation and revolution of the present invention is preferably performed under vacuum conditions; the specific vacuum pressure of the vacuum is not particularly limited in the present invention, and may be a conventional vacuum pressure well known to those skilled in the art, and those skilled in the art can select and adjust the vacuum pressure according to actual production conditions, quality requirements and product performance.
the specific process of step B) of the present invention can preferably be further referred to in table 2, where table 2 is a flow chart of the material stirring process provided by the present invention.
table 2 flow chart of the stirring process provided by the present invention, the above-mentioned size (containing PVDF: NMP of 1:9) was taken out, and an appropriate amount of NMP was added
The invention preferably further comprises the steps of scraping glue, filtering and the like in the process, so that the operation process is optimized. The specific procedures of the scraping and filtering are not particularly limited by the present invention, and the conventional scraping and filtering procedures known to those skilled in the art can be adopted, and those skilled in the art can select and adjust the procedures according to the actual production conditions, quality requirements and product performance. Based on the fact that material loss exists in the actual mixing operation, the actual adding proportion of each raw material is preferably higher than the proportioning proportion by a factor higher than the ratio, and the selection and adjustment can be carried out by a person skilled in the art according to the actual production condition, the quality requirement and the product performance, wherein the ratio of the raw materials to the proportioning proportion is preferably 1.01-1.3 times, more preferably 1.05-1.25 times, and most preferably 1.1-1.2 times. The viscosity of the positive electrode slurry is not particularly limited, and can be selected and adjusted according to the actual production condition, quality requirements and product performance by a person skilled in the art on the basis of the technical scheme of the invention, wherein the viscosity of the positive electrode slurry is preferably 4000-7000 mps, more preferably 4500-6500 mps, and most preferably 5000-6000 mps.
The invention provides a lithium ion battery, which comprises an anode;
the positive electrode is coated with the positive electrode slurry according to any one of the above technical schemes or the positive electrode slurry prepared according to any one of the above technical schemes.
the preparation method of the positive electrode is not particularly limited, and the preparation method of the positive electrode of the lithium ion battery, which is well known to those skilled in the art, is adopted, and the positive electrode slurry prepared by the method is preferably coated on a metal foil (preferably aluminum foil) current collector, and is dried and cut to obtain the positive electrode material pole piece of the lithium ion battery. The invention has no special limitation on other components and preparation processes of the lithium ion battery, and the conventional components and preparation methods of the lithium ion battery, which are well known to those skilled in the art, can be selected and adjusted by those skilled in the art according to actual production conditions, quality requirements and product performance.
the invention obtains a positive pole slurry and a preparation method thereof, the invention creatively combines the two aspects of proportioning and pulping process control in multiple influencing factors of a lithium ion battery, firstly starts from the components and proportion of the positive pole slurry, adds nano Al 2 O 3 in the positive pole slurry, can effectively play the roles of heat insulation and insulation, and improves the safety performance of the battery, and lithium cobaltate and nano Al 2 O 3 form a solid solution, can stabilize crystal lattices, and improve the multiplying power performance and the cycle performance of the battery, and simultaneously, nano Al 2 O 3 coats the lithium cobaltate, thereby improving the thermal stability, improving the cycle capability and the overcharge resistance, inhibiting the generation of oxygen and the decomposition of LiPF 6, reducing the contact of the lithium cobaltate and an electrolyte, reducing the capacity loss, thereby improving the capacity, starts from the slurry preparation process, aiming at the problems existing in the performance of the lithium cobaltate, changes the charging sequence and the charging proportion, optimizes the collocation in the rotation speed, time and rotation stirring mixing process, improves the dispersed discharge capacity in the pulping process, further improves the discharge capacity in the pulping process, and improves the discharge capacity of the battery, and the discharge capacity of the battery, and the lithium battery can still improve the cycle voltage of the battery, and the discharge capacity of the battery, and the.
For further illustration of the present invention, the following will describe in detail a positive electrode slurry, a preparation method thereof, and a lithium ion battery provided by the present invention with reference to examples, but it should be understood that these examples are implemented on the premise of the technical solution of the present invention, and the detailed embodiments and specific operation procedures are given, only for further illustration of the features and advantages of the present invention, but not for limitation of the claims of the present invention, and the scope of protection of the present invention is not limited to the following examples.
Example 1
The solid content (m 1 + m 2 + m 3 + m 4)/(m 1 + m 2 + m 3 + m 4 + m NMP) is 70%, the solid content is weighed according to LCO (SP + KS-6) and PVDF (nano Al 2 O 3) (96.5:1.4:1.8:0.3), and the masses of LCO, SP + KS-6, PVDF and nano Al 2 O 3 are respectively marked as m 1, m 2, m 3 and m 4.
firstly, glue preparation
Preparing rubber according to the content of PVDF in rubber material being 10 percent
The PVDF was weighed to a mass of 1.2m 3 and the NMP required mass of 10.8m 3, taking into account the process losses, see Table 3.
TABLE 3
Secondly, stirring the materials
conductive agent and other additive adding mode:
10% of the above size (containing PVDF: NMP: 1:9) was taken out, and the masses of LCO, SP, KS-6 and nano Al 2 O 3 were respectively designated as m 1, m 2 and m 4, and NMP to be supplemented was weighed and designated as m 5, see Table 4.
TABLE 4
The slurry prepared by the process of example 1 is used for preparing a batch of Lithium Cobaltate (LCO) batteries according to a conventional process, the maximum difference of internal resistances is within 3%, the maximum difference of initial discharge specific capacities of the batteries at 1C is 2.5mAh/g (about 1.5%), and the batch batteries show good consistency, so that the slurry obtained under the stirring scheme has good stability and uniformity.
under the stirring mode, the first discharge capacity of the prepared battery at 1C is 165mAh/g (charge cut-off voltage is 4.35V, and discharge cut-off voltage is 3V), and after 100 cycles, the capacity retention rate is 97.5%. This shows that the capacity of the material is well exerted, and the rate capability and the cycle performance of the battery are excellent.
Compared with the conventional material selection and process, the battery slurry prepared by the technical scheme of the invention is more stable and uniform, and the conductivity of the material can be better improved by matching the SP and the KS-6, and the capacity, the safety performance, the rate capability and the cycle performance of the battery can be finally improved by the action of the nano Al 2 O 3.
Example 2
The solid content (m 1 + m 2 + m 3 + m 4)/(m 1 + m 2 + m 3 + m 4 + m NMP) ═ 70%, and the LCO (SP + KS-6) and PVDF (nano Al 2 O 3) ═ 96.5:1.7:1.8:0 (i.e. no nano Al 2 O 3 was added), and the masses of LCO, SP + KS-6, PVDF and nano Al 2 O 3 were respectively marked as m 1, m 2, m 3 and m 4, and the stirring step was kept the same as that of example 1.
as in example 2: the maximum difference of the internal resistances of the prepared battery is within 3%, the maximum difference of the first discharge specific capacity of the battery 1C is 2.4mAh/g (about 1.45%), and the battery shows good consistency, so that the stability and uniformity of the slurry obtained under the stirring scheme are good.
In this manner, the first average discharge capacity of the obtained battery at 1C was 166mAh/g (charge cut-off voltage 4.35V, discharge cut-off voltage 3V), and the capacity retention ratio was 90.3% after 100 cycles. The capacity of the material is well exerted, but the cycle performance is poor.
From example 2, it can be seen that:
the addition of the Al 2 O 3 additive does not change the uniformity and stability of the slurry, and the uniformity and stability of the slurry are directly related to the stirring process;
The Al 2 O 3 additive can improve the rate capability and the cycle performance of the battery to a great extent.
example 3
Compared with example 1, the feeding mode of the material is changed.
Weighing 70% of solid content (m 1 + m 2 + m 3 + m 4)/(m 1 + m 2 + m 3 + m 4 + m NMP), weighing 70% of LCO (SP + KS-6), PVDF (nano Al 2 O 3) (96.5:1.4:1.8:0.3), and respectively recording the masses of LCO, SP + KS-6, PVDF and nano Al 2 O 3 as m 1, m 2, m 3 and m 4
Glue making
The total mass of the required gel was taken as M, and the gel was prepared according to 1.2 times the mass of the required gel (i.e. 1.2M), the required mass of PVDF was weighed to be 1.2M 3, the gel was prepared according to the content of PVDF being 10%, the mass of NMP being 10.8M 3, and the specific parameters are shown in Table 5.
TABLE 5
Secondly, stirring the materials
conductive agent and other additive adding mode:
the gel (containing PVDF:1M 3; NMP:9M 3) with mass M was taken out, the masses of LCO, SP + KS-6 and nano Al 2 O 3 were respectively marked as M 1, M 2 and M 3, NMP to be supplemented was weighed, and the mass was marked as M 5, see Table 6.
TABLE 6
the maximum difference of the internal resistances of the prepared battery can reach 8%, the maximum difference of the first discharge specific capacity of the battery 1C is 6.2mAh/g (about 3.75%), and the consistency of the battery is poor, so that the stability and uniformity of the slurry obtained under the charging scheme are poor.
Under the stirring mode, the first average discharge capacity of the prepared battery at 1C is 162mAh/g (charge cut-off voltage is 4.35V, and discharge cut-off voltage is 3V), and after 100 cycles, the capacity retention rate is 94.5%.
from example 3, it can be seen that:
the addition mode of the slurry has great influence on the stability and uniformity of the slurry, and simultaneously, the uniformity and stability of the slurry also influence the exertion of the battery capacity and the cycle performance.
Example 4
The solid content (m1+ m2+ m3+ m4)/(m1+ m2+ m3+ m4+ nmp) is 70%, and the mass of LCO, SP + KS-6, PVDF and nano Al 2 O 3 are respectively marked as m 1, m 2, m 3 and m 4 by weighing LCO, SP + KS-6, PVDF and nano Al 2 O 3 (96.5:1.4:1.8: 0.3).
glue making
The total mass of the required gel was taken as M, and the gel was prepared according to 1.2 times the mass of the required gel (i.e. 1.2M), the required mass of PVDF was weighed to be 1.2M 3, the gel was prepared according to the content of PVDF being 10%, the mass of NMP being 10.8M 3, and the specific parameters are shown in Table 7.
TABLE 7
secondly, stirring the materials
Conductive agent and other additive adding mode:
The gel (containing PVDF:1M 3; NMP:9M 3) with mass M was taken out, the masses of LCO, SP + KS-6 and nano Al 2 O 3 were respectively marked as M 1, M 2 and M 4, NMP to be supplemented was weighed, and the mass was marked as M 5, see Table 8.
TABLE 8
the maximum difference of the internal resistances of the prepared battery can be 6%, the maximum difference of the first discharge specific capacity of the battery 1C is 4.6mAh/g (about 2.79%), and the consistency of the battery is poor, so that the stability and uniformity of the slurry obtained under the stirring scheme are poor.
Under the stirring mode, the first average discharge capacity of the prepared battery at 1C is 164mAh/g (charge cut-off voltage is 4.35V, and discharge cut-off voltage is 3V), and after the battery is cycled for 100 times, the capacity retention rate is 95.8%.
From example 4, it can be seen that:
The stirring speed and the stirring time greatly affect the stability and uniformity of the slurry, and simultaneously, the uniformity and stability of the slurry also affect the exertion of the battery capacity and the cycle performance.
The foregoing detailed description of a positive electrode slurry and method of making and a lithium ion battery according to the present invention, and the principles and embodiments of the present invention described herein using specific examples, is provided merely to facilitate an understanding of the methods and their core concepts, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention. The scope of the invention is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims (8)

1. a preparation method of positive electrode slurry is characterized by comprising the following steps:
A) Carrying out a first series of rotation and revolution on the binder and the solvent, stirring and mixing to obtain a sizing material;
The step A1) is specifically as follows:
Stirring and mixing 60% ~ 70% of binder and solvent under the conditions of first rotation and revolution, second rotation and revolution and third rotation and revolution respectively to obtain a section of mixture;
the step A2) is specifically as follows:
adding 30% ~ 40% of binder into the mixture obtained in the previous step, and stirring and mixing under the conditions of fourth revolution, fifth revolution and sixth revolution respectively to obtain rubber material;
B) conducting a second series of rotation, revolution, stirring and mixing on the conductive agent, the nano aluminum oxide and the solvent, then adding the sizing material and the lithium cobaltate material prepared in the step, and conducting a third series of rotation, revolution, stirring and mixing to obtain anode slurry;
The step B) is specifically as follows:
B1) Stirring and mixing the conductive agent, the nano aluminum oxide and the solvent under the seventh autorotation and revolution condition, and then stirring and mixing under the eighth autorotation and revolution condition to obtain a premix;
B2) Carrying out third series of rotation, revolution, stirring and mixing on the pre-mixture, the sizing material and the lithium cobaltate material to obtain anode slurry;
wherein the content of the first and second substances,
93. 93 ~ 97.5 parts by weight of lithium cobaltate material;
1.5 parts by weight of conductive agent 1.5 ~ 2.5.5;
1.5 ~ 3 parts by weight of binder;
0.1 weight part of nano aluminum oxide, namely 0.1 ~ 0.5;
A solvent.
2. the method according to claim 1, wherein the conductive agent includes one or more of conductive carbon black, conductive graphite, graphene, carbon fiber, and carbon nanotube;
The binder comprises one or more of polyvinylidene fluoride, polytetrafluoroethylene and styrene-butadiene latex;
The solvent comprises one or more of N-methyl pyrrolidone, dimethyl acetamide, acetone and N, N-dimethylformamide;
The solid content of the positive electrode slurry was 50% ~ 75%.
3. the production method according to claim 2, characterized in that the positive electrode slurry includes:
94 ~ 96.5.5 parts by weight of a lithium cobaltate material;
1.7 ~ 2.3.3 parts by weight of KS-6 and Super P;
1.8 ~ 2.5.2.5 parts by weight of PVDF;
0.3 ~ 0.5.5 parts by weight of nano alumina.
4. the preparation method according to claim 1, wherein the step a) is specifically:
A1) Firstly, carrying out rotation, revolution and stirring mixing on 60% ~ 70% of binder and solvent to obtain a section of mixture;
A2) and (3) performing rotation, revolution and stirring on the mixture obtained in the step one and 30% ~ 40% of adhesive again to obtain the sizing material.
5. The production method according to claim 1, wherein the revolution speed of the first rotation and revolution is 5 ~ 15r/min, the rotation speed of the first rotation and revolution is 500 ~ 800r/min, the time of the first rotation and revolution is 10 ~ 20 min;
The revolution speed of the second rotation and revolution is 15 ~ 25r/min, the rotation speed of the second rotation and revolution is 1200 ~ 1500r/min, and the time of the second rotation and revolution is 20 ~ 30 min;
The revolution speed of the third rotation and revolution is 25 ~ 35r/min, the rotation speed of the third rotation and revolution is 2000 ~ 2500r/min, and the time of the third rotation and revolution is 60 ~ 100 min;
the revolution speed of the fourth revolution is 5 ~ 15r/min, the rotation speed of the fourth revolution is 500 ~ 800r/min, and the time of the fourth revolution is 10 ~ 20 min;
the revolution speed of the fifth rotation and revolution is 15 ~ 25r/min, the rotation speed of the fifth rotation and revolution is 1200 ~ 1500r/min, and the time of the fifth rotation and revolution is 20 ~ 30 min;
the revolution speed of the sixth rotation and revolution is 25 ~ 35r/min, the rotation speed of the sixth rotation and revolution is 2000 ~ 2500r/min, and the time of the sixth rotation and revolution is 120 ~ 150 min;
the third rotation and revolution is carried out under the vacuum condition; the sixth rotation and revolution is performed under vacuum conditions.
6. the method according to claim 1 ~ 5, wherein the step of preparing the mixture of the first and second materials,
the revolution speed of the seventh rotation and revolution is 15 ~ 25r/min, the rotation speed of the seventh rotation and revolution is 500 ~ 800r/min, and the time of the seventh rotation and revolution is 10 ~ 20 min;
the revolution speed of the eighth rotation and revolution is 20 ~ 30r/min, the rotation speed of the eighth rotation and revolution is 800 ~ 1500r/min, and the time of the eighth rotation and revolution is 30 ~ 50 min;
the eighth rotation and revolution is performed under a vacuum condition.
7. the preparation method according to claim 6, wherein the step B2) is specifically:
Respectively stirring and mixing the pre-mixture and 30% ~ 40% of sizing material under the conditions of ninth rotation and revolution and tenth rotation and revolution to obtain a primary mixture;
then adding 53% of ~ 61% of lithium cobaltate material into the primary mixture obtained in the step, stirring and mixing under the eleventh rotation and revolution condition, then adding 24% of ~ 33% of lithium cobaltate material, stirring and mixing under the twelfth rotation and revolution condition, then adding 10% of ~ 18% of lithium cobaltate material, stirring and mixing under the thirteenth rotation and revolution condition and the fourteenth rotation and revolution condition respectively, and obtaining a middle-grade mixture;
finally, adding 60 percent ~ 70 percent of sizing material into the intermediate mixture obtained in the step, and stirring and mixing the sizing material under the conditions of a fifteenth rotation and revolution, a sixteenth rotation and revolution, a seventeenth rotation and revolution and an eighteenth rotation and revolution respectively to obtain anode slurry;
the revolution speed of the ninth rotation and revolution is 15 ~ 25r/min, the rotation speed of the ninth rotation and revolution is 500 ~ 800r/min, and the time of the ninth rotation and revolution is 5 ~ 10 min;
the revolution speed of the tenth rotation and revolution is 25 ~ 35r/min, the rotation speed of the tenth rotation and revolution is 2000 ~ 2500r/min, and the time of the tenth rotation and revolution is 30 ~ 60 min;
The revolution speed of the eleventh revolution is 15 ~ 25r/min, the rotation speed of the eleventh revolution is 800 ~ 1000r/min, and the time of the eleventh revolution is 5 ~ 10 min;
the revolution speed of the twelfth rotation and revolution is 10 ~ 20r/min, the rotation speed of the twelfth rotation and revolution is 800 ~ 1000r/min, and the time of the twelfth rotation and revolution is 5 ~ 10 min;
The revolution speed of the thirteenth revolution is 10 ~ 20r/min, the rotation speed of the thirteenth revolution is 800 ~ 1000r/min, the time of the thirteenth revolution is 5 ~ 10 min;
The revolution speed of the fourteenth rotation and revolution is 15 ~ 25r/min, the rotation speed of the fourteenth rotation and revolution is 1800 ~ 2000r/min, and the time of the fourteenth rotation and revolution is 60 ~ 90 min;
the revolution speed of the fifteenth rotation and revolution is 10 ~ 20r/min, the rotation speed of the fifteenth rotation and revolution is 800 ~ 1000r/min, and the time of the fifteenth rotation and revolution is 5 ~ 10 min;
the revolution speed of the sixteenth rotation and revolution is 20 ~ 30r/min, the rotation speed of the sixteenth rotation and revolution is 1500 ~ 2000r/min, and the time of the sixteenth rotation and revolution is 5 ~ 10 min;
the revolution speed of the seventeenth revolution is 25 ~ 35r/min, the rotation speed of the seventeenth revolution is 2000 ~ 2500r/min, and the time of the seventeenth revolution is 120 ~ 150 min;
The revolution speed of the eighteenth rotation and revolution is 15 ~ 25r/min, the rotation speed of the eighteenth rotation and revolution is 1500 ~ 2000r/min, and the time of the eighteenth rotation and revolution is 5 ~ 10 min;
The tenth rotation and revolution is carried out under the vacuum condition; the fourteenth autorotation and revolution is carried out under the vacuum condition; the sixteenth rotation and revolution is carried out under the vacuum condition; the seventeenth rotation and revolution is carried out under the vacuum condition; the eighteenth rotation and revolution is performed under vacuum conditions.
8. a lithium ion battery, comprising a positive electrode;
The positive electrode is coated with the positive electrode slurry prepared by the preparation method according to claim 1 ~ 7.
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