WO2023202636A1 - 负极材料及其制备方法和锂离子电池 - Google Patents

负极材料及其制备方法和锂离子电池 Download PDF

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Publication number
WO2023202636A1
WO2023202636A1 PCT/CN2023/089279 CN2023089279W WO2023202636A1 WO 2023202636 A1 WO2023202636 A1 WO 2023202636A1 CN 2023089279 W CN2023089279 W CN 2023089279W WO 2023202636 A1 WO2023202636 A1 WO 2023202636A1
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Prior art keywords
negative electrode
electrode material
particle size
silicon
based active
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PCT/CN2023/089279
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English (en)
French (fr)
Inventor
邓志强
谢维
庞春雷
任建国
贺雪琴
Original Assignee
贝特瑞新材料集团股份有限公司
惠州市贝特瑞新材料科技有限公司
惠州市鼎元新能源科技有限公司
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Priority claimed from CN202210769600.9A external-priority patent/CN116979052A/zh
Application filed by 贝特瑞新材料集团股份有限公司, 惠州市贝特瑞新材料科技有限公司, 惠州市鼎元新能源科技有限公司 filed Critical 贝特瑞新材料集团股份有限公司
Priority to KR1020237033602A priority Critical patent/KR20230150873A/ko
Priority to EP23769098.7A priority patent/EP4297130A1/en
Priority to JP2023560802A priority patent/JP2024519441A/ja
Publication of WO2023202636A1 publication Critical patent/WO2023202636A1/zh

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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
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • H01M4/139—Processes of manufacture
    • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • 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
    • H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
    • 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
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present disclosure relates to the technical field of secondary batteries, and in particular to a negative electrode material, a preparation method thereof, and a lithium-ion battery.
  • Improving the cyclic expansion performance of lithium-ion batteries can be achieved by improving the chemical structure, conductivity and other characteristics of battery materials. It can also be achieved by adjusting the characteristics of battery materials and improving the characteristics of battery electrodes, such as the distribution of material particles in the electrodes. Uniformity, consistency. However, the existing technology has problems such as uneven distribution of material particles in the pole piece and poor consistency.
  • the negative electrode material includes a silicon-based active material, and the silicon-based active material includes at least one of SiO x , SiO x /C, SiO x /M, Si, Si/C and Si/M, where 0 ⁇ x ⁇ 2, the M includes at least one of metals, non-metals, metal oxides and non-metal oxides.
  • the particle size distribution of the negative electrode material is: 0 ⁇ D5 ⁇ 65 ⁇ m , 0 ⁇ D25 ⁇ 69 ⁇ m , 0 ⁇ D75 ⁇ 75 ⁇ m , 0 ⁇ D95 ⁇ 79 ⁇ m .
  • the infrared spectrum test of the negative electrode material has a peak in the range of wave number 3200cm -1 to 3600cm -1 .
  • the wadell sphericity of the negative electrode material is ⁇ 0.8.
  • the particle size D50 of the silicon-based active material is greater than 0 ⁇ m and less than or equal to 80 ⁇ m.
  • the specific surface area of the silicon-based active material is 0-10 m 2 /g, and is not 0.
  • the tap density of the silicon-based active material is 0.5g/m 3 to 2g/m 3 .
  • the negative electrode material further includes a doping material doped in the silicon-based active material.
  • the negative electrode material further includes a doping material doped in the silicon-based active material, and the doping material includes at least one of an alkali metal, an alkaline earth metal, an alkali metal oxide, and an alkaline earth metal oxide. kind.
  • the negative electrode material further includes a doping material doped in the silicon-based active material, and the weight percentage b of the doping material in the negative electrode material satisfies: 0 ⁇ b ⁇ 20%.
  • the particle size distribution of the negative electrode material is: 0 ⁇ D5 ⁇ 65 ⁇ m , 0 ⁇ D16 ⁇ 67 ⁇ m , 0 ⁇ D84 ⁇ 77 ⁇ m , 0 ⁇ D95 ⁇ 79 ⁇ m .
  • the sorting coefficient B and the peak coefficient A of the particle size distribution of the negative electrode material satisfy: 0 ⁇ B/A ⁇ 5.
  • the negative electrode material further includes a coating layer located on the surface of the silicon-based active material, and the coating layer includes at least one of a flexible polymer and a conductive material.
  • the conductive material includes flake graphite and nanocarbon materials.
  • the flexible polymer includes natural flexible polymers and/or synthetic flexible polymers.
  • the flexible polymer includes polyolefin and its derivatives, polyvinyl alcohol and its derivatives, polyacrylic acid and its derivatives, polyamide and its derivatives, carboxymethylcellulose and its derivatives, seaweed At least one of acid and its derivatives and polycarbonate and its derivatives.
  • the flexible polymer has a weight average molecular weight of 2,000-1,000,000.
  • the flexible polymer contains thermal cross-linking functional groups, and the thermal cross-linking functional groups include at least one of epoxy group, carboxyl group, hydroxyl group, amino group, double bond and triple bond.
  • the flake graphite includes natural flake graphite and/or artificial flake graphite.
  • the nanocarbon-based material includes at least one of conductive graphite, graphene, carbon nanotubes and carbon nanofibers.
  • the mass percentage of the flexible polymer is 0-10%, and does not include 0.
  • the mass percentage of the flake graphite is 0-20%, and does not include 0.
  • the mass percentage of the nanocarbon-based material is 0-5%, and does not include 0.
  • the thickness of the coating layer is 10 nm to 5000 nm.
  • the mass proportion of the coating layer in the negative electrode material is 0-20%, and does not include 0%.
  • the mass proportion of the coating layer in the negative electrode material is 2% to 10%.
  • the present disclosure also provides a preparation method of anode material, including the following steps:
  • the negative electrode material includes a silicon-based active material, and the silicon-based active material includes at least one of SiO x , SiO x /C, SiO x /M, Si, Si/C and Si/M, where 0 ⁇ x ⁇ 2, the M includes at least one of metals, non-metals, metal oxides and non-metal oxides.
  • the method of preparing powdered negative electrode material includes: powdering a silicon-based active material to obtain the powdered negative electrode material.
  • the powdering method includes crushing and ball milling.
  • the device used for crushing includes a crusher, and the crushing power p of the crusher satisfies: 0 ⁇ p ⁇ 300kW.
  • the device used for the ball mill includes a ball mill, and the rotation speed v1 of the ball mill satisfies: 0 ⁇ v1 ⁇ 1500rpm.
  • the device used to adjust the particle size includes a classifier; the frequency f of the induced draft fan of the classifier satisfies: 0 ⁇ f ⁇ 100Hz.
  • the sorting coefficient B and the peak coefficient A satisfy: 0 ⁇ B/A ⁇ 5.
  • the particle size D50 of the silicon-based active material is greater than 0 ⁇ m and less than or equal to 80 ⁇ m.
  • the method for preparing powdered negative electrode material further includes: carbon coating the powdered silicon-based active material with carbon material to obtain the powdered negative electrode material; the carbon material accounts for 10% of the negative electrode material.
  • the weight percentage a satisfies: 0 ⁇ a ⁇ 15%.
  • the method of preparing powdered negative electrode material further includes: coating the powdered silicon-based active material with a polymer or carbon-coating the powdered silicon-based active material with a carbon material, and then coating the powdered silicon-based active material with a polymer.
  • the powdery negative electrode material is obtained.
  • the polymer coating method includes the following steps:
  • a conductive material is added to the flexible polymer solution, where the conductive material includes flake graphite and nanocarbon materials, to obtain a mixed coating liquid;
  • the negative electrode material precursor is heat treated to obtain the powdered negative electrode material.
  • the flexible polymer contains thermal cross-linking functional groups, and the thermal cross-linking functional groups include at least one of epoxy group, carboxyl group, hydroxyl group, amino group, double bond and triple bond.
  • the solvent includes water, methanol, ethanol, polypyrrolidone, isopropyl alcohol, acetone, petroleum ether, tetrahydrofuran, ethyl acetate, N,N-dimethylacetamide, N,N-dimethylform At least one of amide, n-hexane and halogenated hydrocarbon.
  • the antisolvent includes a poor solvent for flexible polymers.
  • the anti-solvent includes methanol, ethanol, polypyrrolidone, isopropyl alcohol, acetone, petroleum ether, tetrahydrofuran, ethyl acetate, N,N-dimethylacetamide, N,N-dimethylformamide , n-hexane and at least one of halogenated hydrocarbons.
  • the temperature of the heat treatment is 100°C-400°C.
  • the heat treatment time is 2h-12h.
  • the method of preparing powdered negative electrode material further includes: doping the powdered silicon-based active material with a doping material to obtain the powdered negative electrode material.
  • the doping material includes at least one of alkali metals, alkaline earth metals, alkali metal oxides and alkaline earth metal oxides.
  • the weight percentage b of the doping material in the negative electrode material satisfies: 0 ⁇ b ⁇ 20%.
  • the present disclosure also provides a lithium ion battery, including the negative electrode material described in any one of the above or the negative electrode material prepared by the preparation method described in any one of the above.
  • Figure 1 is a flow chart of the preparation method of the anode material of the present disclosure
  • Figure 2 is a particle size distribution diagram of the lithium-ion battery negative electrode material obtained in Example 1 of the present disclosure
  • Figure 3 is a particle size distribution diagram of the lithium-ion battery negative electrode material obtained in Example 13 of the present disclosure.
  • Figure 4 is a particle size distribution diagram of the lithium-ion battery negative electrode material obtained in Example 17 of the present disclosure.
  • Figure 5 is a particle size distribution diagram of the lithium-ion battery negative electrode material obtained in Example 22 of the present disclosure.
  • Figure 6 is a particle size distribution diagram of the lithium-ion battery negative electrode material obtained in Comparative Example 1 of the present disclosure
  • Figure 7 is an SEM image of the lithium-ion battery negative electrode material obtained in Example 1 of the present disclosure.
  • Figure 8 is an SEM image of the lithium-ion battery negative electrode material obtained in Example 13 of the present disclosure.
  • Figure 9 is an SEM image of the lithium-ion battery negative electrode material obtained in Example 17 of the present disclosure.
  • Figure 10 is an SEM image of the lithium-ion battery negative electrode material obtained in Example 22 of the present disclosure.
  • Figure 11 is an SEM image of the lithium ion battery negative electrode material obtained in Comparative Example 1 of the present disclosure.
  • particle size is used interchangeably with the term “particle size” and refers to the size of the particles.
  • particle size is expressed as diameter.
  • particle size may be expressed as having the same behavior as the particle.
  • a certain sphere diameter is used as the equivalent diameter of the particle.
  • cumulative curve also known as “cumulative frequency curve” is a method of graphically representing the cumulative frequency of sedimentary material (grit).
  • One embodiment of the present disclosure provides a negative electrode material (silicon-based negative electrode material).
  • the negative electrode material includes a silicon-based active material (active material), and the silicon-based active material includes at least one of SiO x , SiO x /C, SiO x /M, Si, Si/C and Si/M, where 0 ⁇ x ⁇ 2, M includes at least one of metals, non-metals, metal oxides and non-metal oxides.
  • SiO Composite materials of Si and SiO2 are provided.
  • SiOx /C may be a carbon-containing SiOx material.
  • SiO x /M can be a composite material containing SiO x and M, or a composite material containing Si and three elements or component materials containing M, Si, and O.
  • Si/M may be a composite material containing two elements or components, Si and M.
  • a negative electrode material with a suitable particle size distribution can be obtained, which can solve the problems of poor conductivity, poor cycle and rate performance of existing negative electrode materials.
  • This solution adjusts the peak coefficient A of the particle size of the negative electrode material to satisfy: 0 ⁇ A ⁇ 3, which can make the distribution at the tail ends of both sides of the particle size (particle size) distribution curve (i.e., particle size distribution) of the negative electrode material more concentrated, and there will be no interference with the particles. Particles whose median diameters differ too much.
  • the peak coefficient A can be 0.5, 1, 1.2, 1.5, 1.8, 2, 2.5, 2.8 or 3, etc., or an interval value between any two endpoint values mentioned above, and of course it can also be other values within the above range. The value is not limited here.
  • the prepared negative electrode material can have an ideal high specific capacity. When A>3, there are particles in the material that are greatly different from the median particle size, resulting in a large difference in particle size of each particle of the material. After coating into pole pieces, during the battery cycle, some stress is concentrated, causing the pole pieces to If it becomes powdery or even falls off, the battery will fail quickly.
  • the particle size distribution of the negative electrode material is: 0 ⁇ D 5 ⁇ 65 ⁇ m, 0 ⁇ D 25 ⁇ 69 ⁇ m, 0 ⁇ D 75 ⁇ 75 ⁇ m, 0 ⁇ D 95 ⁇ 79 ⁇ m.
  • This solution selects the sorting coefficient B of the particle size distribution of the negative electrode material to satisfy: 0 ⁇ B ⁇ 3, which can ensure that the particle size of the negative electrode material is more concentrated in the middle section of the particle size distribution curve (between both sides).
  • the binder is evenly distributed, which improves the peeling strength of the pole piece and helps the pole piece to build a stable and complete conductive network.
  • the particle size distribution of the negative electrode material can be concentrated by selecting the sorting coefficient B of the particle size.
  • the sorting coefficient B can be 0.5, 1, 1.2, 1.5, 1.8, 2, 2.5, 2.8 or 3, etc., or any of the above.
  • the interval value between the two endpoint values can also be other values within the above range, which is not limited here.
  • the particle size distribution of the negative electrode material is: 0 ⁇ D5 ⁇ 65 ⁇ m , 0 ⁇ D16 ⁇ 67 ⁇ m , 0 ⁇ D84 ⁇ 77 ⁇ m , 0 ⁇ D95 ⁇ 79 ⁇ m .
  • the sorting coefficient B and the peak coefficient A satisfy: 0 ⁇ B/A ⁇ 5.
  • the ratio B/A of the sorting coefficient B and the peak coefficient A can be 0.5, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.2, 4.5, 4.8 or 5, etc., or the interval value between any two of the above endpoint values. Of course, it can also be other values within the above range, which are not limited here.
  • the ratio B/A of the sorting coefficient B and the peak coefficient A the agglomeration of silicon-based active material particles can be more effectively avoided, thereby effectively exerting the high performance of the battery.
  • B/A >5 it will cause the silicon-based active material particles to aggregate after the negative electrode material is slurried and coated, affecting battery performance.
  • the infrared spectrum test of the negative electrode material has a peak in the range of wave numbers from 3200 cm -1 to 3600 cm -1 . This shows that the negative electrode material of the present disclosure has polar groups, such as -OH groups, which is more conducive to the combination of the negative electrode material and the binder.
  • the negative electrode material has a wadell sphericity ⁇ 0.6. The higher the sphericity, the greater the consistency of the pole pieces.
  • the negative electrode material has a wadell sphericity ⁇ 0.8.
  • the wadell sphericity of the negative electrode material can be 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, etc., or an interval value between any two endpoint values mentioned above.
  • the negative electrode material further includes a coating layer located on the surface of the silicon-based active material, and the coating layer includes at least one of a flexible polymer and a conductive material.
  • the conductive material includes at least one of flake graphite or nanocarbon-based materials.
  • flexible polymers include natural flexible polymers and/or synthetic flexible polymers.
  • flexible polymers include polyolefins and derivatives thereof, polyvinyl alcohol and derivatives thereof, polyacrylic acid and derivatives thereof, polyamides and derivatives thereof, carboxymethyl cellulose and derivatives thereof, seaweed At least one of acid and its derivatives and polycarbonate and its derivatives.
  • the flexible polymer has a weight average molecular weight of 2,000-1,000,000.
  • the weight average molecular weight of the flexible polymer is within the above range, which can effectively avoid the agglomeration of the negative electrode material and at the same time better exert the buffering effect of the flexible polymer on the negative electrode material.
  • the flexible polymer may have a weight average molecular weight of, for example, 5000-500000, 10000-100000 or 50000-90000, such as 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 20000, 30000, 50000 , 80000, 100000, 200000, 300000, 500000, 80000 or 1000000, etc., or an interval value between any two of the above endpoint values.
  • 5000-500000, 10000-100000 or 50000-90000 such as 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 20000, 30000, 50000 , 80000, 100000, 200000, 300000, 500000, 80000 or 1000000, etc.
  • it can also be other values within the above range, which is not limited here.
  • the flexible polymer contains thermal crosslinking functional groups, and the thermal crosslinking functional groups include at least one of epoxy groups, carboxyl groups, hydroxyl groups, amino groups, double bonds, and triple bonds.
  • flake graphite includes natural flake graphite and/or artificial flake graphite.
  • the nanocarbon-based material includes at least one of conductive graphite, graphene, carbon nanotubes, and carbon nanofibers.
  • the mass percentage of the flexible polymer is 0-10%, and does not include 0.
  • the mass percentage of the flexible polymer is within the above range, which can effectively avoid the agglomeration of the negative electrode material, and at the same time effectively exert the buffering effect of the flexible polymer on the negative electrode material, without affecting the characteristics of the negative electrode material of the present disclosure. Ideal high specific capacity.
  • the mass percentage of the flexible polymer may be, for example, 0.1%-8.5%, 1%-7.5% or 2.5%-5%, such as 1%, 2%, 3 %, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc., or the interval value between any two of the above endpoint values, of course it can also be other values within the above range, here No restrictions.
  • the mass percentage of the flake graphite is 0-20%, and does not include 0.
  • the mass percentage of flake graphite is within the above range, which can also effectively avoid the agglomeration of materials during the combination process, while effectively exerting the conductivity of flake graphite, and does not affect the characteristics of the anode material of the present disclosure. Ideal high specific capacity.
  • the mass percentage of flake graphite may be, for example, 0.1%-16%, 1%-14% or 5%-8%, such as 1%, 2%, 3% , 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20 %, etc., or the interval value between any two endpoint values mentioned above, of course, it can also be other values within the above range, which is not limited here.
  • the mass percentage of nanocarbon-based materials is 0-5%, and does not include 0.
  • the mass percentage of nanocarbon materials is within the above range, it can also effectively avoid the agglomeration of materials during the combination process, while effectively exerting the conductive properties of nanocarbon materials, and does not affect the negative electrode of the present disclosure.
  • the material has a high specific capacity.
  • the mass percentage of nanocarbon-based materials can be, for example, 0.1%-4.6%, 0.9%-4.1% or 1.9%-2.1%, such as 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5% or 5%, etc., or an interval value between any two of the above endpoint values.
  • 0.1%-4.6%, 0.9%-4.1% or 1.9%-2.1% such as 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5% or 5%, etc.
  • an interval value between any two of the above endpoint values can also be other values within the above range. This is not limited.
  • the thickness of the cladding layer ranges from 10 nm to 5000 nm.
  • the thickness of the cladding layer may be, for example, 50nm to 1000nm, 100nm to 800nm, or 300nm to 500nm, such as 10nm, 50nm, 100nm, 200nm, 500nm, 800nm, 1000nm, 2000nm, 3000nm, 4000nm or 5000nm, or the above.
  • the interval value between any two endpoint values can of course also be other values within the above range, which is not limited here.
  • the mass proportion of the coating layer in the negative electrode material is 0-20%, and does not include 0%.
  • the mass proportion of the coating layer in the negative electrode material may be, for example, 2%-18%, 4%-15%, or 6%-12%, such as 1%, 2%, 3%, 4%, 5 %, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc., or any Of course, the interval value between the two endpoint values can also be other values within the above range, which is not limited here.
  • the mass proportion of the coating layer in the negative electrode material is 2% to 10%.
  • the thickness and proportion of the coating layer of the negative electrode material are within the above range of the present disclosure, which can effectively exert a buffering effect on the negative electrode material, effectively ensure the conductive performance of the negative electrode material, and do not affect the negative electrode material of the present disclosure. High specific capacity.
  • the particle size D50 of the silicon-based active material is greater than 0 ⁇ m and less than or equal to 80 ⁇ m, and the particle size testing method includes a laser scattering method.
  • the particle size D50 of the silicon-based active material may be, for example, 10 ⁇ m-70 ⁇ m, 20 ⁇ m-60 ⁇ m, or 30 ⁇ m-50 ⁇ m, such as 1 ⁇ m, 5 ⁇ m, 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 30 ⁇ m, 40 ⁇ m, 50 ⁇ m, 60 ⁇ m, 70 ⁇ m, or 80 ⁇ m, or any two
  • the interval value between the endpoint values can of course also be other values within the above range, which is not limited here.
  • the reasonable selection of the particle size of the silicon-based active material can ensure the cycle performance, battery expansion and other properties of the lithium-ion battery anode material after it is made into the battery. If the particle size D50 of the silicon-based active material is greater than 80 ⁇ m, It will have a negative impact on the cycle performance and battery expansion performance of the battery.
  • the specific surface area of the silicon-based active material is 0-10 m 2 /g, and is not 0.
  • the silicon-based active material may have a specific surface area of, for example, 1 m 2 /g to 9 m 2 /g, 2 m 2 /g to 8 m 2 /g, or 3 m 2 /g to 7 m 2 /g, such as 1 m 2 /g, 2m 2 /g, 3m 2 /g, 4m 2 /g, 5m 2 /g, 6m 2 /g, 7m 2 /g, 8m 2 /g, 9m 2 /g or 10m 2 /g, etc., or any two
  • the interval value between the endpoint values can of course also be other values within the above range, and is not limited here.
  • the specific surface area of the silicon-based active material is within the above range, which can ensure the high specific capacity and high first capacity efficiency of the anode material of the present disclosure.
  • the silicon-based active material has a tap density of 0.5 g/m 3 to 2 g/m 3 .
  • the tap density of the silicon-based active material may be 0.7g/m 3 ⁇ 1.8g/m 3 , 0.9g/m 3 ⁇ 1.6g/m 3 or 1.0g/m 3 ⁇ 1.4g/m 3 , Such as 0.5g/m 3 , 0.6g/m 3 , 0.8g/m 3 , 1.0g/m 3 , 1.2g/m 3 , 1.5g/m 3 , 1.8g/m 3 or 2g/m 3 , etc., or
  • the interval value between any two endpoint values can of course also be other values within the above range, which is not limited here. Without being bound by theory, if the tap density of the silicon-based active material is within the above range, it can also ensure high specific capacity and high first capacity efficiency in the anode material of the present disclosure.
  • the negative electrode material further includes a doping material doped in the silicon-based active material, and the doping material includes at least one of an alkali metal, an alkaline earth metal, an alkali metal oxide, and an alkaline earth metal oxide;
  • the weight percentage b of the doping material in the negative electrode material satisfies: 0 ⁇ b ⁇ 20%.
  • the alkali metal can be selected from lithium, sodium, and potassium; the alkaline earth metal can be selected from magnesium, calcium, strontium, and barium; the alkali metal oxide can be selected from lithium oxide, sodium oxide, and potassium oxide; the alkaline earth metal
  • the oxide may be selected from magnesium oxide, calcium oxide, strontium oxide, and barium oxide.
  • the weight percentage b of the doping material in the negative electrode material can be 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18% or 20%, etc., or an interval between any two endpoint values. value, of course, it can also be other values within the above range, and is not limited here.
  • the intrinsic conductivity of the silicon-based active material can be improved. Further, by selecting the type and content of the doping material, the conductivity of the silicon-based active material can be more effectively improved. Conductivity.
  • the negative electrode materials of the above embodiments can be combined arbitrarily as long as there is no conflict with each other.
  • the particle size of the silicon-based active material and the specific surface area of the silicon-based active material are combined to limit the combination.
  • An embodiment of the present disclosure also provides a preparation method of anode material.
  • the preparation method includes the following steps:
  • Step S100 prepare powdery negative electrode material
  • the negative electrode material includes a silicon-based active material, and the silicon-based active material includes at least one of SiO x , SiO x /C, SiO x /M, Si, Si/C and Si/M, where 0 ⁇ x ⁇ 2, M Including at least one of metals, non-metals, metal oxides and non-metal oxides.
  • the method of preparing powdered negative electrode material further includes: powdering the silicon-based active material to obtain powdered negative electrode material.
  • the silicon-based active material is first powdered to obtain a powdery negative electrode material with suitable particle size, and then the peak coefficient A of the particle size of the powdery negative electrode material is reasonably calculated.
  • the silicon-based negative electrode materials with appropriate particle size distribution which can solve the problems of low first Coulombic efficiency, poor conductivity, poor cycle and rate performance of existing silicon-based active materials as negative electrode materials.
  • methods of powdering include crushing and ball milling.
  • the device used for crushing includes a crusher, and the crushing power p of the crusher satisfies: 0 ⁇ p ⁇ 300kW.
  • the device used for ball milling includes a ball mill, and the rotation speed v1 of the ball mill satisfies: 0 ⁇ v1 ⁇ 1500rpm.
  • the device used for particle size adjustment includes a classifier; the induced draft fan frequency f of the classifier satisfies: 0 ⁇ f ⁇ 100Hz.
  • the sorting coefficient B and the peak coefficient A satisfy: 0 ⁇ B/A ⁇ 5.
  • the particle size D50 of the silicon-based active material is greater than 0 ⁇ m and less than or equal to 80 ⁇ m.
  • the crushing power p of the crusher can be, for example, 40kW-260kW, 80kW-210kW or 120kW-180kW, such as 5kW, 10kW, 20kW, 50kW, 100kW, 150kW, 200kW, 250kW or 300kW, etc., or any two endpoints
  • the interval value between the values, the rotation speed v1 of the ball mill can be, for example, 50rpm-1400rpm, 300rpm-1200rpm or 500rpm-900rpm, such as 200rpm, 400rpm, 600rpm, 800rpm, 1000rpm, 1200rpm or 1500rpm, etc., or between any two endpoint values
  • the interval value of can also be other values within the above range, which is not limited here. Without being bound by theory, through reasonable selection of the crushing power p and the ball mill speed v1 used in the powdering process, silicon-based active materials with appropriate particle sizes can be obtained, which is beneficial to the adjustment of the particle size in the later stage.
  • the induced draft fan frequency f of the classifier can be, for example, 6Hz-95Hz, 25Hz-75Hz or 35Hz-65Hz, such as 1Hz, 5Hz, 10Hz, 20Hz, 30Hz, 50Hz, 70Hz, 90Hz or 100Hz, etc., or any two
  • the interval value between the endpoint values can of course also be other values within the above range, and is not limited here.
  • the sorting coefficient B and peak coefficient A of the particle size distribution of the negative electrode material can be satisfied: 0 ⁇ B ⁇ 3, 0 ⁇ A ⁇ 3 .
  • the particle size D50 of the silicon-based active material may be, for example, 4 ⁇ m-80 ⁇ m, 25 ⁇ m-75 ⁇ m, or 45 ⁇ m-65 ⁇ m, such as 1 ⁇ m, 5 ⁇ m, 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 30 ⁇ m, 40 ⁇ m, 50 ⁇ m, 60 ⁇ m, 70 ⁇ m or 80 ⁇ m, etc., or an interval value between any two endpoint values.
  • it can also be other values within the above range, which are not limited here.
  • the reasonable selection of the particle size of the silicon-based active material can ensure the cycle performance, battery expansion and other properties of the lithium-ion battery anode material after it is made into the battery. If the particle size D50 of the silicon-based active material is greater than 80 ⁇ m, It will have a negative impact on the cycle performance and battery expansion performance of the battery.
  • the method for preparing powdered negative electrode material also includes: carbon coating the powdered silicon-based active material with carbon material to obtain powdered negative electrode material; the weight percentage a of the carbon material in the negative electrode material satisfies: 0 ⁇ a ⁇ 15%.
  • the weight percentage a of the carbon material in the negative electrode material may be 2.5%-14.5%, 4.5%-10.5% or 6.5%-8.5%, such as 1%, 2%, 3%, 4%, 5%, 6 %, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%, etc., or an interval value between any two endpoint values, of course it can also be within the above range Other values are not limited here.
  • by adding carbon material to the negative electrode material and coating the surface of the silicon-based active material with the carbon material it can effectively solve the volume change and conductivity problems of the silicon-based lithium-ion battery negative electrode material during the process of inserting and removing lithium. question.
  • the carbon coating method includes: mixing a third raw material including a fired product and an organic carbon source in a protective atmosphere or vacuum environment and performing heat treatment.
  • the above-mentioned carbon coating method includes: mixing the third raw material including the above-mentioned burned product and the organic carbon source in a protective atmosphere or vacuum environment and performing heat treatment.
  • the above carbon coating can be listed as gas phase carbon coating and/or solid phase carbon coating.
  • the carbon coating of the present disclosure adopts the method of gas phase carbon coating.
  • the specific method includes: heating the above-mentioned fired product to 600°C-1000°C in a protective atmosphere, passing in organic carbon source gas, and keeping the temperature 0.5 Cool after h-10h.
  • the organic carbon source gas may be hydrocarbons (such as alkanes, cycloalkanes, alkenes, alkynes and aromatic hydrocarbons, etc.), and may be at least one of methane, ethylene, acetylene and benzene.
  • the heat treatment temperature in the gas phase carbon coating method can be, for example, 650°C-950°C, 750°C-850°C, or 780°C-820°C, such as 600°C, 700°C, 800°C, 900°C, 1000°C etc.
  • the heat preservation time of the heat treatment can be specifically, for example, 1.0h-9.0h, 3.0h-7.0h or 5.0h-6.0h, such as 0.5h, 1.5h, 2.5h, 3.5h, 4.5h, 5.5h, 6.5h, 7.5h, 8.5h, 9.5h, 10h, etc., or the interval value between any two endpoint values, is not limited here.
  • the temperature of heat treatment can be 700-900°C
  • the holding time of heat treatment can be 3-9 hours.
  • the carbon coating of the present disclosure adopts solid-phase carbon coating.
  • the specific method includes: fusing the above-mentioned calcined product with the carbon source for more than 0.5 hours, and then heating the obtained carbon mixture at 600°C-1000°C. Carbonize for 2h-6h and cool.
  • the carbon source optionally includes at least one of polyolefins, resins, rubbers, sugars (such as glucose, sucrose, starch, cellulose, etc.), organic acids, and asphalt.
  • the heat treatment temperature in the solid-phase carbon coating method can be, for example, 650°C-950°C, 710°C-880°C, or 750°C-810°C, such as 600°C, 700°C, 800°C, 900°C, 1000°C °C, etc.
  • the heat treatment holding time can specifically be 2h, 3h, 4h, 5h, 6h, etc., or an interval value between any two endpoint values, which is not limited here.
  • the temperature of heat treatment can be 700°C-900°C, and the holding time of heat treatment can be 3h-5h.
  • fusion is optionally performed in a fusion machine, and the rotation speed of the fusion machine is 500r/min-3000r/min.
  • the rotation speed of the fusion machine can be, for example, 900r/min-2600r/min, 1100r/min-2200r/min or 1400r/min-1800r/min, such as 500r/min, 800r/min, 1000r/min, 1500r/min. min, 2000r/min, 2500r/min, 3000r/min, etc., or the interval value between any two endpoint values, there is no limit here.
  • the rotation speed of the fusion machine can be 1000-3000r/min.
  • the tool gap width of the fusion machine can be selected as needed, for example, 0.5cm.
  • the protective atmosphere in the above carbon coating method can be selected from at least one of helium, neon, argon and nitrogen.
  • the method for preparing powdered negative electrode material further includes: coating the powdered silicon-based active material with a polymer, or carbon-coating the powdered silicon-based active material with a carbon material, The polymer coating is then carried out to obtain powdered negative electrode material.
  • the polymer coating method includes the following steps:
  • the conductive material includes flake graphite and nanocarbon materials to obtain a mixed coating liquid
  • the negative electrode material precursor is heat treated to obtain powdered negative electrode material.
  • the flexible polymer contains thermal crosslinking functional groups, and the thermal crosslinking functional groups include at least one of epoxy groups, carboxyl groups, hydroxyl groups, amino groups, double bonds, and triple bonds.
  • solvents include water, methanol, ethanol, polypyrrolidone, isopropyl alcohol, acetone, petroleum ether, tetrahydrofuran, ethyl acetate, N,N-dimethylacetamide, N,N-dimethylform At least one of amide, n-hexane and halogenated hydrocarbon.
  • the antisolvent includes a poor solvent for the flexible polymer.
  • antisolvents include methanol, ethanol, polypyrrolidone, isopropyl alcohol, acetone, petroleum ether, tetrahydrofuran, ethyl acetate, N,N-dimethylacetamide, N,N-dimethylformamide , n-hexane and at least one of halogenated hydrocarbons.
  • the temperature of the heat treatment is 100°C-400°C, and the time of the heat treatment is 2h-12h.
  • the temperature of the heat treatment may be, for example, 140°C-360°C, 180°C-280°C, or 220°C-260°C, such as 100°C, 120°C, 150°C, 180°C, 200°C, 220°C, 250°C, 280°C, 300°C, 320°C, 350°C, 380°C or 400°C, etc., or an interval value between any two endpoint values.
  • 140°C-360°C, 180°C-280°C, or 220°C-260°C such as 100°C, 120°C, 150°C, 180°C, 200°C, 220°C, 250°C, 280°C, 300°C, 320°C, 350°C, 380°C or 400°C, etc., or an interval value between any two endpoint values.
  • it can also be other values within the above range, which are not limited here.
  • the time of heat treatment can be, for example, 4.5h-10.5h, 6.5h-9.5h or 7.5h-8.5h, such as 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h or 12h, etc., or any Of course, the interval value between the two endpoint values can also be other values within the above range, which is not limited here.
  • the method of preparing the powdered negative electrode material further includes: doping the powdered silicon-based active material with a doping material to obtain the powdered negative electrode material.
  • the doping material includes at least one of an alkali metal, an alkaline earth metal, an alkali metal oxide, and an alkaline earth metal oxide.
  • the weight percentage b of the doping material in the negative electrode material satisfies: 0 ⁇ b ⁇ 20%.
  • the alkali metal can be selected from at least one of lithium, sodium or potassium; the alkaline earth metal can be selected from at least one of magnesium, calcium, strontium or barium; the alkali metal oxide can be selected from lithium oxide, sodium oxide Or at least one of potassium oxide; the alkaline earth metal oxide can be selected from at least one of magnesium oxide, calcium oxide, strontium oxide, and barium oxide.
  • the weight percentage b of the doping material in the negative electrode material can be 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18% or 20%, etc., and of course it can also be other values within the above range. , no limitation is made here.
  • the intrinsic conductivity of the silicon-based active material can be improved. Further, by selecting the type and content of the doping material, the conductivity of the silicon-based active material can be more effectively improved. Conductivity. It should be noted that doping the powdered silicon-based active material with a doping material may be performed before carbon coating or after carbon coating.
  • An embodiment of the present disclosure also provides a lithium-ion battery, which includes the above-mentioned negative electrode material or the lithium-ion battery negative electrode material prepared by the above-mentioned preparation method.
  • the present disclosure provides a negative electrode material and a preparation method thereof and a lithium-ion battery, which solves the problem of uneven material particles and poor conductivity, cycle stability and rate performance of existing silicon-based materials in battery negative electrode sheets. question.
  • the negative electrode material provided by the present disclosure adjusts the peak coefficient A of the particle size distribution of the negative electrode material to satisfy: 0 ⁇ A ⁇ 3, which can make the distribution of the tail ends of the particle size of the negative electrode material on both sides more concentrated, and will not appear to be the same as the median particle size. Particles that are too different.
  • the peak coefficient A of the particle size distribution By rationally selecting the peak coefficient A of the particle size distribution, the consistency of each particle of the negative electrode material can be ensured, so that when the negative electrode material is slurried and coated, the stability of the slurry can be improved, and the binding agent and conductive agent on the surface of different particles can be improved. The better the distribution consistency, the better the consistency of the coated pole piece.
  • the prepared negative electrode material can have an ideal high specific capacity.
  • the peak coefficient A of the particle size distribution of the negative electrode material satisfies: 0 ⁇ A ⁇ 3, which can make the coating layer included in the negative electrode material, such as a flexible polymer, on each particle
  • the good thickness consistency of the coating layer enables the flexible polymer to better buffer the volume changes during the charging and discharging process of the material, improves the material's cycle performance and reduces the expansion of the material.
  • the present disclosure can ensure that the particle size of the negative electrode material is concentrated in the middle section (between both sides) of the particle size distribution curve, thereby making When the negative electrode material is combined with a binder to form a pole piece, the binder is evenly distributed, which improves the peeling strength of the pole piece and helps the pole piece build a stable and complete conductive network.
  • the present disclosure can more effectively avoid the agglomeration of silicon-based active material particles by specifically limiting the ratio B/A of the sorting coefficient B and the peak coefficient A, thereby effectively enabling the negative electrode material to effectively exert the high performance of the battery.
  • FIG. 1 A method for preparing negative electrode materials for lithium ion batteries is shown in Figure 1, including the following steps S10 to S30:
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 100kW, and the speed v1 of the ball mill is 800rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7%.
  • step S30 an airflow classifier is used to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 55 Hz to obtain the final negative electrode material.
  • a method for preparing negative electrode materials for lithium ion batteries includes the following steps S10 to S30:
  • Step S10 take 1kg Si bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the Si powder to about 5 ⁇ m; the crushing power p of the crusher is 100kW, and the speed v1 of the ball mill is 800rpm. .
  • step S20 the Si powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 6.7%.
  • step S30 an airflow classifier is used to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 65 Hz to obtain the final negative electrode material.
  • a method for preparing negative electrode materials for lithium ion batteries includes the following steps S10 to S30:
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 100kW, and the speed v1 of the ball mill is 800rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 6.8%.
  • step S30 an airflow classifier is used to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 35 Hz to obtain the final negative electrode material.
  • a method for preparing negative electrode materials for lithium ion batteries includes the following steps S10 to S30:
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 70kW, and the speed v1 of the ball mill is 1100rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7.1%.
  • step S30 an airflow classifier is used to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 70 Hz to obtain the final negative electrode material.
  • a method for preparing negative electrode materials for lithium ion batteries includes the following steps S10 to S30:
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 150kW, and the speed v1 of the ball mill is 600rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7.1%.
  • step S30 use an airflow classifier to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 40 Hz to obtain the final negative electrode material.
  • a method for preparing negative electrode materials for lithium ion batteries includes the following steps S10 to S30:
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 150kW, and the speed v1 of the ball mill is 650rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7.3%.
  • step S30 use an airflow classifier to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 46 Hz to obtain the final negative electrode material.
  • a method for preparing negative electrode materials for lithium ion batteries includes the following steps S10 to S30:
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 110kW, and the speed v1 of the ball mill is 750rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7%.
  • step S30 use an airflow classifier to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 75 Hz to obtain the final negative electrode material.
  • a method for preparing negative electrode materials for lithium ion batteries includes the following steps S10 to S30:
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 120kW, and the speed v1 of the ball mill is 700rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7.2%.
  • step S30 use an airflow classifier to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 60 Hz to obtain the final negative electrode material.
  • a method for preparing negative electrode materials for lithium ion batteries includes the following steps S10 to S30:
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 20 ⁇ m; the crushing power p of the crusher is 90kW, and the speed v1 of the ball mill is 400rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 6.9%.
  • step S30 an airflow classifier is used to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 58 Hz to obtain the final negative electrode material.
  • a method for preparing negative electrode materials for lithium ion batteries includes the following steps S10 to S40:
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 20 ⁇ m; the crushing power p of the crusher is 90kW, and the speed v1 of the ball mill is 600rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7.1%.
  • step S30 the SiO powder coated with carbon in step S20 is doped with a doping material; the doping material is MgO, and the weight percentage b of the doping material in the negative electrode material is 5%.
  • step S40 use an airflow classifier to adjust the particle size of the powder obtained in step S20.
  • the frequency f of the induced draft fan of the classifier is 56 Hz to obtain the final negative electrode material.
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 100kW, and the speed v1 of the ball mill is 800rpm. .
  • step S20 an airflow classifier is used to adjust the particle size of the powder obtained in step S10.
  • the induced draft fan frequency f of the classifier is 58 Hz to obtain the final negative electrode material.
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 20 ⁇ m; the crushing power p of the crusher is 90kW, and the speed v1 of the ball mill is 600rpm. .
  • step S20 the SiO powder coated with carbon in step S10 is doped with a doping material; the doping material is MgO, and the weight percentage b of the doping material in the negative electrode material is 5%.
  • step S30 use an airflow classifier to adjust the particle size of the powder obtained in step S20.
  • the frequency f of the induced draft fan of the classifier is 55 Hz to obtain the final negative electrode material.
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 20 ⁇ m; the crushing power p of the crusher is 90kW, and the speed v1 of the ball mill is 600rpm. .
  • step S20 the SiO powder coated with carbon in step S10 is doped with a doping material; the doping material is MgO, and the weight percentage b of the doping material in the negative electrode material is 5%.
  • step S30 the powder obtained in step S20 is carbon-coated with carbon material; the weight percentage a of the carbon material in the negative electrode material is 7.3%.
  • step S40 use an airflow classifier to adjust the particle size of the powder obtained in step S20.
  • the frequency f of the induced draft fan of the classifier is 56 Hz to obtain the final negative electrode material.
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 100kW, and the speed v1 of the ball mill is 800rpm. .
  • Step S20 use a fusion machine to process the SiO powder obtained in step S10, the fusion machine speed is 1000r/min, and the processing time is 6h;
  • step S30 the SiO powder obtained in step S20 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 6.9%.
  • step S40 use an airflow classifier to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 55 Hz to obtain the final negative electrode material.
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 100kW, and the speed v1 of the ball mill is 800rpm. .
  • Step S20 use a fusion machine to process the SiO powder obtained in step S10, the fusion machine speed is 1000r/min, and the processing time is 6.2h;
  • step S30 the SiO powder obtained in step S20 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7.0%.
  • step S40 use an airflow classifier to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 55 Hz to obtain the final negative electrode material.
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 100kW, and the speed v1 of the ball mill is 800rpm. .
  • Step S20 use a fusion machine to process the SiO powder obtained in step S10, the fusion machine speed is 2500r/min, and the processing time is 8.5h;
  • step S30 the SiO powder obtained in step S20 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7.1%.
  • step S40 use an airflow classifier to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 55 Hz to obtain the final negative electrode material.
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 100kW, and the speed v1 of the ball mill is 800rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7%.
  • step S30 an airflow classifier is used to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 55 Hz to obtain the negative electrode material after the particle size has been adjusted.
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 110kW, and the speed v1 of the ball mill is 750rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7%.
  • step S30 an airflow classifier is used to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 20 Hz to obtain the negative electrode material after the particle size has been adjusted.
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 20 ⁇ m; the crushing power p of the crusher is 90kW, and the speed v1 of the ball mill is 600rpm. .
  • step S20 the SiO powder coated with carbon in step S10 is doped with a doping material; the doping material is Li 2 O, and the weight percentage b of the doping material in the negative electrode material is 4.5%.
  • step S30 the powder obtained in step S20 is carbon-coated with carbon material; the weight percentage a of the carbon material in the negative electrode material is 7.2%.
  • step S40 use an airflow classifier to adjust the particle size of the powder obtained in step S20.
  • the frequency f of the induced draft fan of the classifier is 56 Hz to obtain the final negative electrode material.
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 110kW, and the speed v1 of the ball mill is 750rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7%.
  • step S30 an airflow classifier is used to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 20 Hz to obtain the anode material after the particle size has been adjusted.
  • a method for preparing negative electrode materials for lithium ion batteries includes the following steps S10 to S30:
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 100W, and the speed v1 of the ball mill is 1000rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 6.9%.
  • step S30 an airflow classifier is used to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 110 Hz to obtain the final negative electrode material.
  • a method for preparing negative electrode materials for lithium ion batteries includes the following steps S10 to S30:
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 110kW, and the speed v1 of the ball mill is 750rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7%.
  • step S30 an airflow classifier is used to adjust the particle size of the powder obtained in step S20.
  • the induced draft fan frequency f of the classifier is 10 Hz to obtain the final negative electrode material.
  • a method for preparing negative electrode materials for lithium ion batteries includes the following steps S10 to S30:
  • Step S10 take 1kg Si bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the Si powder to about 5 ⁇ m; the crushing power p of the crusher is 150kW, and the speed v1 of the ball mill is 550rpm. .
  • step S20 the Si powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 6.9%.
  • step S30 use an airflow classifier to adjust the particle size of the powder obtained in step S20.
  • the frequency f of the induced draft fan of the classifier is 53 Hz to obtain the final negative electrode material.
  • a method for preparing negative electrode materials for lithium ion batteries includes the following steps S10 to S30:
  • Step S10 take 1kg of SiO bulk material for later use, use a crusher and a ball mill to powder the bulk material, and adjust the D50 of the SiO powder to about 5 ⁇ m; the crushing power p of the crusher is 150kW, and the speed v1 of the ball mill is 550rpm. .
  • step S20 the SiO powder obtained in step S10 is carbon-coated with a carbon material; the weight percentage a of the carbon material in the negative electrode material is 7.1%.
  • step S30 use an airflow classifier to adjust the particle size of the powder obtained in step S20.
  • the frequency f of the induced draft fan is 65 Hz to obtain the final negative electrode material.
  • Particle size distribution test Use Malvern 2000 particle size analyzer to test the particle size distribution of the material, set to a refractive index of 2.42, opacity of 8%-20%, and the dispersant is water;
  • Battery consistency test Prepare according to methods (2) and (3), prepare 10 identical batteries, and compare the consistency of the 50-week capacity retention rate and the 50-week pole piece expansion rate of the 10 batteries. Consistency was expressed by the relative standard deviation (RSD) of the 50-week capacity retention rate and the 50-week pole piece expansion rate among the 10 groups.
  • RSS relative standard deviation
  • a. Preparation of lithium-ion battery Mix the composite materials prepared in the above examples and comparative examples with graphite in a mass ratio of 15:85 to obtain the negative active material, and then mix the negative active material, conductive carbon black, CMC and SBR according to the mass ratio of 15:85. Mix evenly with a mass ratio of 92:4:2:2, coat it on copper foil, prepare a negative electrode sheet, and use the hundred-grid knife method to test the peel strength of the negative electrode sheet.
  • the battery test and experimental process record data are shown in Table 1 below.
  • the particle size distribution results of Examples 1, 13, 17, 22 and Comparative Example 1 are shown in Figures 2 to 5 and Figure 6 respectively.
  • Examples 1, 13, 17 , 22 and Comparative Example 1 are shown in Figures 7 to 10 and Figure 11 respectively.
  • the lithium-ion battery prepared using the anode material of the present disclosure has excellent capacity efficiency, cycle performance, charge and discharge performance and expansion performance, and also has high peel strength, which can effectively improve the performance of the lithium-ion battery. performance.
  • Examples 21-23 and Comparative Example 1 By comparing Examples 21-23 and Comparative Example 1, it can be seen that by selecting the peak coefficient A of the particle size distribution, the present disclosure can obtain an anode material with a relatively suitable particle size distribution, so that the performance of the anode material can be improved, especially It improves the rate performance of the negative electrode material.
  • the present disclosure can achieve a particle size distribution of the negative electrode material by selecting the peak coefficient A and the sorting coefficient B of the particle size, and selecting B/A. It is more concentrated and further improves the 50-week capacity retention rate, rate performance and peel strength of the negative electrode material, and further reduces the expansion rate of the negative electrode material.
  • the present disclosure provides a negative electrode material, a preparation method thereof, and a lithium-ion battery.
  • the negative electrode material of the present disclosure can ensure the consistency of the negative electrode material particles by limiting the peak coefficient A of the particle size distribution of the negative electrode material, so that after coating The pole pieces have good consistency, which in turn makes the battery performance consistent and improves battery performance; in addition, by further limiting the sorting coefficient B and the ratio B/A between the two, the negative electrode material can have better particle size distribution and Higher battery performance, therefore has excellent practical performance and wide application prospects.

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Abstract

本公开涉及二次电池技术领域，尤其涉及一种负极材料及其制备方法和锂离子电池，负极材料的粒径分布的峰值系数A满足：0＜A≤3；其中，A＝(D95-D5)/[2.5*(D75-D25)]，D95、D5、D75、D25分别代表累积曲线上体积百分含量达到95％、5％、75％、25％时负极材料的粒径。本公开的负极材料具有合适的峰值系数A，能保证负极材料颗粒的一致性，从而使得涂布后的极片一致性好，进而使电池的性能一致性高，提升电池性能。

Description

负极材料及其制备方法和锂离子电池
相关申请的交叉引用
本公开要求于2022年04月21日提交中国专利局，申请号为CN2022104270714、发明名称为“负极材料及其制备方法和锂离子电池”的中国专利申请以及于2022年06月30日提交中国专利局，申请号为CN2022107696009、发明名称为“硅基负极材料及其制备方法和锂离子电池”的中国专利申请的优先权，其全部内容通过引用结合在本公开中。
技术领域
本公开涉及二次电池技术领域，尤其涉及一种负极材料及其制备方法和锂离子电池。
背景技术
随着锂离子电池的应用不断拓展和加深，对于锂离子电池性能的要求也越来越多，特别是在电池的能量密度方面，传统的石墨负极材料因其理论克比容量较低的特点，已经不足以满足日益增长的市场需求。作为一种高比容量的负极材料，硅基材料近年来备受关注。
硅基负极材料比容量超过3000mAh/g，但应用于锂离子电池时，相对于石墨材料，有较差的循环稳定性和较高的电池膨胀率，限制了它的实际应用。因此开发一种循环稳定性好，膨胀率低的材料具有重要的意义。
改善锂离子电池的循环膨胀性能，可以通过改善电池材料化学结构、导电性等特性来实现，也可以通过调整电池材料的特性，改善电池极片的特性来实现，例如极片中材料颗粒的分布均匀性、一致性。然而现有技术既然存在极片中材料颗粒分布不均匀以及一致性差的问题。
发明内容
本公开提供一种负极材料，所述负极材料的粒径分布的峰值系数A满足：0＜A≤3；其中，A＝(D95-D5)/[2.5*(D75-D25)]，D95、D5、D75、D25分别代表累积曲线上体积百分含量达到95％、5％、75％、25％时负极材料的粒径；
所述负极材料包括硅基活性材料，所述硅基活性材料包括SiOx、SiOx/C、SiOx/M、Si、Si/C和Si/M中的至少一种，其中，0＜x≤2，所述M包括金属、非金属、金属氧化物以及非金属氧化物中的至少一种。
可选地，所述负极材料的粒径分布为：0＜D5≤65μm，0＜D25≤69μm，0＜D75≤75μm，0＜D95≤79μm。
可选地，所述负极材料的红外光谱测试在波数为3200cm-1-3600cm-1范围内存在包峰。
可选地，所述负极材料的wadell球形度≥0.8。
可选地，所述硅基活性材料的粒径D50大于0μm，且小于等于80μm。
可选地，所述硅基活性材料的比表面积为0-10m2/g，且不为0。
可选地，所述硅基活性材料的振实密度为0.5g/m3～2g/m3。
可选地，所述负极材料还包括掺杂在所述硅基活性材料中的掺杂材料。
可选地，所述负极材料还包括掺杂在所述硅基活性材料中的掺杂材料，所述掺杂材料包括碱金属、碱土金属、碱金属氧化物和碱土金属氧化物中的至少一种。
可选地，所述负极材料还包括掺杂在所述硅基活性材料中的掺杂材料，所述掺杂材料占所述负极材料的重量百分比b满足：0＜b≤20％。
可选地，所述负极材料的粒径分布的分选系数B满足：0＜B≤3，其中，B＝(D84-D16)/4+(D95-D5)/6.6，D84、D16、D95、D5分别代表累积曲线上体积百分含量达到84％、16％、95％、5％时负极材料的粒径。
可选地，所述负极材料的粒径分布为：0＜D5≤65μm，0＜D16≤67μm，0＜D84≤77μm，0＜D95≤79μm。
可选地，所述负极材料的粒径分布的分选系数B和所述峰值系数A满足：0＜B/A≤5。
可选地，所述负极材料还包括位于所述硅基活性材料表面的包覆层，所述包覆层包括柔性聚合物和导电材料中的至少一种。
可选地，所述导电材料包括鳞片石墨和纳米碳类材料。
可选地，所述柔性聚合物包括天然的柔性聚合物和/或合成的柔性聚合物。
可选地，所述柔性聚合物包括聚烯烃及其衍生物、聚乙烯醇及其衍生物、聚丙烯酸及其衍生物、聚酰胺及其衍生物、羧甲基纤维素及其衍生物、海藻酸及其衍生物和聚碳酸酯及其衍生物中的至少一种。
可选地，所述柔性聚合物的重均分子量为2000-1000000。
可选地，所述柔性聚合物上含有热交联型官能团，所述热交联型官能团包括环氧基、羧基、羟基、氨基、双键和叁键中的至少一种。
可选地，所述鳞片石墨包括天然鳞片石墨和/或人造鳞片石墨。
可选地，所述纳米碳类材料包括导电石墨、石墨烯、碳纳米管和碳纳米纤维中的至少一种。
可选地，以所述负极材料的总质量为100％计，所述柔性聚合物的质量百分比为0-10％，且不包含0。
可选地，以所述负极材料的总质量为100％计，所述鳞片石墨的质量百分比为0-20％，且不包含0。
可选地，以所述负极材料的总质量为100％计，所述纳米碳类材料的质量百分比为0-5％，且不包含0。
可选地，所述包覆层的厚度为10nm～5000nm。
可选地，所述包覆层在所述负极材料中的质量占比为0-20％，且不包含0。
可选地，所述包覆层在所述负极材料中的质量占比为2％～10％。
本公开还提供一种负极材料的制备方法，包括如下步骤：
制备粉状负极材料；
对制备的粉状负极材料进行粒径调整，以得到负极材料；所述负极材料的粒径分布的峰值系数A满足：0＜A≤3；其中，A＝(D95-D5)/[2.5*(D75-D25)]，D95、D5、D75、D25分别代表累积曲线上体积百分含量达到95％、5％、75％、25％时负极材料的粒径；
所述负极材料包括硅基活性材料，所述硅基活性材料包括SiOx、SiOx/C、SiOx/M、Si、Si/C和Si/M中的至少一种，其中，0＜x≤2，所述M包括金属、非金属、金属氧化物以及非金属氧化物中的至少一种。
可选地，所述负极材料的粒径分布的分选系数B满足：0＜B≤3，其中，B＝(D84-D16)/4+(D95-D5)/6.6，D84、D16、D95、D5分别代表累积曲线上体积百分含量达到84％、16％、95％、5％时的粒径。
可选地，所述制备粉状负极材料的方法包括：将硅基活性材料粉体化得到所述粉状负极材料。
可选地，所述粉体化的方法包括破碎和球磨。
可选地，所述破碎采用的装置包括破碎机，所述破碎机的破碎功率p满足：0＜p≤300kW。
可选地，所述球磨采用的装置包括球磨机，所述球磨机的转速v1满足：0＜v1≤1500rpm。
可选地，所述粒径调整采用的装置包括分级机；所述分级机的引风机频率f满足：0＜f≤100Hz。
可选地，所述分选系数B和所述峰值系数A满足：0＜B/A≤5。
可选地，所述硅基活性材料的粒径D50大于0μm，且小于等于80μm。
可选地，所述制备粉状负极材料的方法还包括：将粉体化的硅基活性材料采用碳材料进行碳包覆后得到所述粉状负极材料；所述碳材料占所述负极材料的重量百分比a满足：0＜a≤15％。
可选地，所述制备粉状负极材料的方法还包括：将粉体化的硅基活性材料进行聚合物包覆或者将粉体化的硅基活性材料采用碳材料进行碳包覆后，再得到所述粉状负极材料。
可选地，所述聚合物包覆方法包括以下步骤：
将柔性聚合物溶解于溶剂中，得到柔性聚合物溶液；
在搅拌的条件下，向所述柔性聚合物溶液中加入导电材料，所述导电材料包含鳞片石墨和纳米碳类材料，得到混合包覆液；
向所述混合包覆液中加入反溶剂，搅拌，得到过饱和化后的混合包覆液；
在搅拌的条件下，向所述过饱和化后的混合包覆液中加入硅基活性物质，搅拌，分离，得到负极材料前驱体；及
对所述负极材料前驱体进行热处理，得到所述粉状负极材料。
可选地，所述柔性聚合物上含有热交联型官能团，所述热交联型官能团包括环氧基、羧基、羟基、氨基、双键和叁键中的至少一种。
可选地，所述溶剂包括水、甲醇、乙醇、聚吡咯烷酮、异丙醇、丙酮、石油醚、四氢呋喃、乙酸乙酯、N，N-二甲基乙酰胺、N，N-二甲基甲酰胺、正己烷和卤代烃中的至少一种。
可选地，所述反溶剂包括柔性聚合物的不良溶剂。
可选地，所述反溶剂包括甲醇、乙醇、聚吡咯烷酮、异丙醇、丙酮、石油醚、四氢呋喃、乙酸乙酯、N，N-二甲基乙酰胺、N，N-二甲基甲酰胺、正己烷和卤代烃中的至少一种。
可选地，所述热处理的温度为100℃-400℃。
可选地，所述热处理的时间为2h-12h。
可选地，所述制备粉状负极材料的方法还包括：将粉体化的硅基活性材料采用掺杂材料进行掺杂后得到所述粉状负极材料。
可选地，所述掺杂材料包括碱金属、碱土金属、碱金属氧化物和碱土金属氧化物中的至少一种。
可选地，所述掺杂材料占所述负极材料的重量百分比b满足：0＜b≤20％。
本公开还提供一种锂离子电池，包括上文任一项所述的负极材料或上文任一项所述的制备方法制备的负极材料。
附图说明
图1为本公开负极材料的制备方法流程图；
图2为本公开实施例1得到的锂离子电池负极材料的粒径分布图；
图3为本公开实施例13得到的锂离子电池负极材料的粒径分布图；
图4为本公开实施例17得到的锂离子电池负极材料的粒径分布图；
图5为本公开实施例22得到的锂离子电池负极材料的粒径分布图；
图6为本公开对比例1得到的锂离子电池负极材料的粒径分布图；
图7为本公开实施例1得到的锂离子电池负极材料的SEM图；
图8为本公开实施例13得到的锂离子电池负极材料的SEM图；
图9为本公开实施例17得到的锂离子电池负极材料的SEM图；
图10为本公开实施例22得到的锂离子电池负极材料的SEM图；
图11为本公开对比例1得到的锂离子电池负极材料的SEM图。
此处的附图被并入说明书中并构成本说明书的一部分，示出了符合本公开的实施例，并与说明书一起用于解释本公开的原理。
具体实施方式
以下是本公开示例性实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本公开实施例原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也视为本公开实施例的保护范围。
术语定义
如本文所用，术语“粒度”可以与术语“粒径”互换使用，是指颗粒的大小，对于球体颗粒的粒度用直径表示，对于不规则的颗粒，则可以将与该颗粒有相同行为的某一球体直径作为该颗粒的等效直径。
如本文所用，术语“累积曲线”也称为“累积频率曲线”，是用图像表示沉积物质(砂砾)累积频率的方法。
如本文所用，术语“wadell球形度”是指颗粒外形接近球体的程度，通常定义为将待测颗粒体积相等的球体表面积与待测颗粒的表面积之比，公式为：球形度＝计算得到的与颗粒等体积的球的表面面积/比表面积仪测试得到的颗粒的比表面积。
本公开一实施方式提供一种负极材料(硅基负极材料)，负极材料的粒径分布的峰值系数A满足：0＜A≤3；其中，A＝(D95-D5)/[2.5*(D75-D25)]，D95、D5、D75、D25分别代表累积曲线上体积百分含量达到95％、5％、75％、25％时的粒径；
负极材料包括硅基活性材料(活性材料)，硅基活性材料包括SiOx、SiOx/C、SiOx/M、Si、Si/C和Si/M中的至少一种，其中，0＜x≤2，M包括金属、非金属、金属氧化物以及非金属氧化物中的至少一种。
在一些实施方式中，SiOx可以是单一化合物如SiO2，也可以是多相化合物，如由SiO2、SiO1.5、SiO、SiO0.5等中的一种或更多种组成，也可以是包含Si、SiO2的复合材料。
在一些实施方式中，SiOx/C可以是含有碳的SiOx材料。
在一些实施方式中，SiOx/M可以是含SiOx与M的复合材料，也可以是包含Si和包含M、Si、O三种元素或者组分材料的复合材料。
在一些实施方式中，Si/M可以是包含Si、M两种元素或者组分的复合材料。在上述方案中，通过调整负极材料的粒度(粒径)，得到粒径分布合适的负极材料，能解决现有负极材料存在导电性能较差、循环和倍率性能较差等问题。本方案通过调整负极材料粒径的峰值系数A满足：0＜A≤3，可以使得负极材料的粒度(粒径)分布曲线(即粒度分布)两侧尾端分布更集中，不会出现与粒径中值大小相差过大的颗粒。可选地，峰值系数A可以是0.5、1、1.2、1.5、1.8、2、2.5、2.8或3等，或者上述任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。通过对粒径分布的峰值系数A进行合理选择，能保证负极材料各个颗粒的一致性，使得负极材料调浆涂布时，提高浆料的稳定性，粘结剂和导电剂在负极材料不同颗粒表面的分布一致性越好，从而使得涂布后的极片一致性好，不同颗粒在充放电过程中的膨胀收缩的一致性高，不会因为极片局部颗粒膨胀收缩不均衡导致极片容易被破坏、电池的循环性能劣化和电池的膨胀增加，最终使电池的性能一致性高，并且因为避免了材料颗粒的粒度大的差异性，使得导电剂在各个材料颗粒都能均匀有效的附着，提升了电池的倍率性能。通过对负极材料中硅基活性材料的特殊限定，能使制备的负极材料具有理想的高比容量。当A＞3时，材料中存在与中值粒径相差大的颗粒，导致材料各颗粒的粒度相差较大，涂布成极片后，在电池的循环过程中，部门应力集中，使极片粉化甚至脱落，电池较快失效。
下面详细介绍本方案：
在一些实施方式中，负极材料的粒径分布为：0＜D5≤65μm，0＜D25≤69μm，0＜D75≤75μm，0＜D95≤79μm。
在一些实施方式中，负极材料的粒径分布的分选系数B满足：0＜B≤3，其中，B＝(D84-D16)/4+(D95-D5)/6.6，D84、D16、D95、D5分别代表累积曲线上体积百分含量达到84％、16％、95％、5％时负极材料的粒径。
本方案通过选择负极材料粒径分布的分选系数B满足：0＜B≤3，能够保证负极材料的粒度在粒度分布曲线的中间段(两侧之间)的分布更集中。由此使得负极材料在与粘结剂制成极片时，进而使得粘结剂均匀一致地分布，提高了极片的剥离强度，有利于极片构建稳定和完整的导电网络。
通过选择粒径的分选系数B能够保证负极材料的粒度分布集中，可选地，分选系数B可以是0.5、1、1.2、1.5、1.8、2、2.5、2.8或3等，或者上述任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。
在一些实施方式中，负极材料的粒径分布为：0＜D5≤65μm，0＜D16≤67μm，0＜D84≤77μm，0＜D95≤79μm。
在一些实施方式中，分选系数B和峰值系数A满足：0＜B/A≤5。
可选地，分选系数B和峰值系数A的比值B/A可以是0.5、0.8、1、1.2、1.5、1.8、2、2.5、2.8、3、3.2、3.5、3.8、4、 4.2、4.5、4.8或5等，或者上述任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。不受理论的约束，通过对分选系数B和峰值系数A的比值B/A的具体限定，能够更有效地避免硅基活性材料颗粒的团聚，从而有效发挥电池的高性能，当B/A＞5，则会导致负极材料调浆涂布后硅基活性材料颗粒发生聚集，影响电池性能。
在一些实施方式中，负极材料的红外光谱测试在波数为3200cm-1-3600cm-1范围内存在包峰。由此说明，本公开的负极材料具有极性基团，如-OH基团，更有利于负极材料与粘结剂的结合。
在一些实施方式中，负极材料的wadell球形度≥0.6。球形度越高，极片的一致性也有明显的提升。
在一些实施方式中，负极材料的wadell球形度≥0.8。可选地，负极材料的wadell球形度可以为0.8、0.9、1.0、1.1、1.2、1.3、1.4、1.5等，或者上述任意两点端点值之间的区间值。
在一些实施方式中，负极材料还包括位于硅基活性材料表面的包覆层，包覆层包括柔性聚合物和导电材料中的至少一种。在一些实施方式中，导电材料包括鳞片石墨或纳米碳类材料中的至少一种。
在一些实施方式中，柔性聚合物包括天然的柔性聚合物和/或合成的柔性聚合物。
在一些实施方式中，柔性聚合物包括聚烯烃及其衍生物、聚乙烯醇及其衍生物、聚丙烯酸及其衍生物、聚酰胺及其衍生物、羧甲基纤维素及其衍生物、海藻酸及其衍生物和聚碳酸酯及其衍生物中的至少一种。
在一些实施方式中，柔性聚合物的重均分子量为2000-1000000。不受理论的约束，柔性聚合物的重均分子量在上述范围内，可有效避免负极材料的团聚现象，同时更好地发挥柔性聚合物对于负极材料的缓冲作用。
可选地，柔性聚合物的重均分子量可以为例如5000-500000、10000-100000或50000-90000，诸如2000、3000、4000、5000、6000、7000、8000、9000、10000、20000、30000、50000、80000、100000、200000、300000、500000、80000或1000000等，或者上述任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。
在一些实施方式中，柔性聚合物上含有热交联型官能团，热交联型官能团包括环氧基、羧基、羟基、氨基、双键和叁键中的至少一种。
在一些实施方式中，鳞片石墨包括天然鳞片石墨和/或人造鳞片石墨。
在一些实施方式中，纳米碳类材料包括导电石墨、石墨烯、碳纳米管和碳纳米纤维中的至少一种。
在一些实施方式中，以负极材料的总质量为100％计，柔性聚合物的质量百分比为0-10％，且不包含0。不受理论的约束，柔性聚合物的质量百分比在上述范围内，可以有效比避免负极材料的团聚现象，同时有效发挥柔性聚合物对于负极材料的缓冲作用，且不影响本公开负极材料所具备的理想高比容量。
可选地，以负极材料的总质量为100％计，柔性聚合物的质量百分比可以为例如0.1％-8.5％、1％-7.5％或2.5％-5％，诸如1％、2％、3％、4％、5％、6％、7％、8％、9％或10％等，或者上述任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。
在一些实施方式中，以负极材料的总质量为100％计，鳞片石墨的质量百分比为0-20％，且不包含0。不受理论的约束，鳞片石墨的质量百分比在上述范围内，同样可以有效比避免材料在组合过程中的凝聚现象，同时有效发挥鳞片石墨的导电性，且并不影响本公开负极材料所具备的理想高比容量。可选地，以负极材料的总质量为100％计，鳞片石墨的质量百分比可以为例如0.1％-16％、1％-14％或5％-8％，诸如1％、2％、3％、4％、5％、6％、7％、8％、9％、10％、11％、12％、13％、14％、15％、16％、17％、18％、19％或20％等，或者上述任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。
在一些实施方式中，以负极材料的总质量为100％计，纳米碳类材料的质量百分比为0-5％，且不包含0。不受理论的约束，纳米碳类材料的质量百分比在上述范围内，同样可以有效比避免材料在组合过程中的团聚现象，同时有效发挥纳米碳类材料的导电特性，且并不影响本公开负极材料所具备的高比容量。
可选地，以负极材料的总质量为100％计，纳米碳类材料的质量百分比可以为例如0.1％-4.6％、0.9％-4.1％或1.9％-2.1％，诸如0.5％、1.0％、1.5％、2.0％、2.5％、3.0％、3.5％、4.0％、4.5％或5％等，或者上述任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。
在一些实施方式中，包覆层的厚度为10nm～5000nm。
可选地，包覆层的厚度可以为例如50nm～1000nm、100nm～800nm或300nm～500nm，诸如10nm、50nm、100nm、200nm、500nm、800nm、1000nm、2000nm、3000nm、4000nm或5000nm等，或者上述任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。
在一些实施方式中，包覆层在负极材料中的质量占比为0-20％，且不包含0。
可选地，包覆层在负极材料中的质量占比可以为例如2％-18％、4％-15％或6％-12％，诸如1％、2％、3％、4％、5％、6％、7％、8％、9％、10％、11％、12％、13％、14％、15％、16％、17％、18％、19％或20％等，或任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。
在一些实施方式中，包覆层在负极材料中的质量占比为2％～10％。
不受理论的约束，负极材料的包覆层的厚度和占比在本公开的上述范围之内，可以有效发挥对负极材料的缓冲作用，有效保证负极材料的导电性能，不影响本公开负极材料所具备的高比容量。
在一些实施方式中，硅基活性材料的粒径D50大于0μm，且小于等于80μm，粒径的测试方法包括激光散射法。可选地， 硅基活性材料的粒径D50可以为例如10μm-70μm、20μm-60μm或30μm-50μm，诸如1μm、5μm、10μm、15μm、20μm、30μm、40μm、50μm、60μm、70μm或80μm等，或任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。不受理论的约束，通过硅基活性材料的粒径的合理选择，可以保证锂离子电池负极材料制成电池后的循环性能、电池膨胀等性能，如果硅基活性材料的粒径D50大于80μm，会对电池的循环性能、电池膨胀性能造成不好的影响。
在一些实施方式中，硅基活性材料的比表面积为0-10m2/g，且不为0。可选地，硅基活性材料的比表面积可以为例如1m2/g-9m2/g、2m2/g-8m2/g或3m2/g-7m2/g，诸如1m2/g、2m2/g、3m2/g、4m2/g、5m2/g、6m2/g、7m2/g、8m2/g、9m2/g或10m2/g等，或任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。不受理论的约束，硅基活性材料的比表面积在上述范围内，可以保证本公开负极材料的高比容量和高首次容量效率。
在一些实施方式中，硅基活性材料的振实密度0.5g/m3～2g/m3。可选地，硅基活性材料的振实密度可以为0.7g/m3～1.8g/m3、0.9g/m3～1.6g/m3或1.0g/m3～1.4g/m3，诸如0.5g/m3、0.6g/m3、0.8g/m3、1.0g/m3、1.2g/m3、1.5g/m3、1.8g/m3或2g/m3等，或任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。不受理论的约束，硅基活性材料的振实密度在上述范围内，同样可以保证本公开负极材料中高比容量和高首次容量效率。
在一些实施方式中，负极材料还包括掺杂在硅基活性材料中的掺杂材料，掺杂材料包括碱金属、碱土金属、碱金属氧化物和碱土金属氧化物中的至少一种；
在一些实施方式中，掺杂材料占负极材料的重量百分比b满足：0＜b≤20％。
可选地，碱金属可以选自锂、钠、钾中的一种；碱土金属可以选自镁、钙、锶、钡；碱金属氧化物可以选自氧化锂、氧化钠，氧化钾；碱土金属氧化物可以选自氧化镁，氧化钙，氧化锶，氧化钡。掺杂材料占负极材料的重量百分比b可以为1％、3％、5％、8％、10％、12％、15％、18％或20％等，或任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。不受理论的约束，通过在负极材料中掺杂金属材料，能够提高硅基活性材料的本征电导率，进一步通过对掺杂材料种类和含量的选择，能够更有效地提高硅基活性材料的电导率。
需要说明的是，上述各个实施方式的负极材料在不相互矛盾的情况下，可以任意进行组合，比如硅基活性材料的粒径、硅基活性材料的比表面积进行组合限定等。
本公开一实施方式还提供一种负极材料的制备方法，制备方法包括如下步骤：
步骤S100、制备粉状负极材料；
步骤S200、对制备的粉状负极材料进行粒径调整，以得到负极材料；负极材料的粒径分布的峰值系数A满足：0＜A≤3；其中，A＝(D95-D5)/[2.5*(D75-D25)]，D95、D5、D75、D25分别代表累积曲线上体积百分含量达到95％、5％、75％、25％时负极材料的粒径；
负极材料包括硅基活性材料，硅基活性材料包括SiOx、SiOx/C、SiOx/M、Si、Si/C和Si/M中的至少一种，其中，0＜x≤2，M包括金属、非金属、金属氧化物以及非金属氧化物中的至少一种。
在一些实施方式中，负极材料的粒径分布的分选系数B满足：0＜B≤3，其中，B＝(D84-D16)/4+(D95-D5)/6.6，D84、D16、D95、D5分别代表累积曲线上体积百分含量达到84％、16％、95％、5％时的粒径。
在一些实施方式中，制备粉状负极材料的方法还包括：将硅基活性材料粉体化得到粉状负极材料。
在上述方案中，在粉状负极材料的制备方法中先对硅基活性材料进行粉体化，得到粒径合适的粉状负极材料，再对粉状负极材料的粒径的峰值系数A进行合理选择，得到粒径分布合适的硅基负极材料，能解决现有硅基活性材料作为负极材料存在首次库伦效率低、导电性能较差、循环和倍率性能较差等问题。
在一些实施方式中，粉体化的方法包括破碎和球磨。
在一些实施方式中，破碎采用的装置包括破碎机，破碎机的破碎功率p满足：0＜p≤300kW。
在一些实施方式中，球磨采用的装置包括球磨机，球磨机的转速v1满足：0＜v1≤1500rpm。
在一些实施方式中，粒径调整采用的装置包括分级机；分级机的引风机频率f满足：0＜f≤100Hz。
在一些实施方式中，分选系数B和峰值系数A满足：0＜B/A≤5。
在一些实施方式中，硅基活性材料的粒径D50大于0μm，且小于等于80μm。
可选地，破碎机的破碎功率p可以为例如40kW-260kW、80kW-210kW或120kW-180kW，诸如5kW、10kW、20kW、50kW、100kW、150kW、200kW、250kW或300kW等，或任意两个端点值之间的区间值，球磨机的转速v1可以为例如50rpm-1400rpm、300rpm-1200rpm或500rpm-900rpm，诸如200rpm、400rpm、600rpm、800rpm、1000rpm、1200rpm或1500rpm等，或任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。不受理论的约束，通过对粉体化过程中所采用的破碎功率p、球磨机的转速v1的合理选择，能够得到粒径合适的硅基活性材料，有利于后期粒径的调整。
可选地，分级机的引风机频率f可以为例如6Hz-95Hz、25Hz-75Hz或35Hz-65Hz，诸如1Hz、5Hz、10Hz、20Hz、30Hz、50Hz、70Hz、90Hz或100Hz等，或任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。不受理论的约束，通过对分选机的引风机频率f的合理选择，能够使得负极材料的粒径分布的分选系数B和峰值系数A满足：0＜B≤3，0＜A≤3。
可选地，硅基活性材料的粒径D50可以为例如4μm-80μm、25μm-75μm或45μm-65μm，诸如1μm、5μm、10μm、15μm、 20μm、30μm、40μm、50μm、60μm、70μm或80μm等，或任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。不受理论的约束，通过硅基活性材料的粒径的合理选择，可以保证锂离子电池负极材料制成电池后的循环性能、电池膨胀等性能，如果硅基活性材料的粒径D50大于80μm，会对电池的循环性能、电池膨胀性能造成不好的影响。
在一些实施方式中，制备粉状负极材料的方法还包括：将粉体化的硅基活性材料采用碳材料进行碳包覆后得到粉状负极材料；碳材料占负极材料的重量百分比a满足：0＜a≤15％。
可选地，碳材料占负极材料的重量百分比a可以是2.5％-14.5％、4.5％-10.5％或6.5％-8.5％，诸如1％、2％、3％、4％、5％、6％、7％、8％、9％、10％、11％、12％、13％、14％或15％等，或任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。不受理论的约束，通过在负极材料中添加碳材料，使碳材料包覆于硅基活性材料的表面，能够有效解决硅基锂离子电池负极材料在嵌脱锂过程的体积变化及导电性的问题。
在一些实施方式中，碳包覆的方法包括：在保护性气氛或真空环境中，将包括烧成物和有机碳源的第三原料混合并进行热处理。
上述碳包覆的方法包括：在保护性气氛或真空环境中，将包括上述烧成物和有机碳源在内的第三原料混合并进行热处理。
具体地，上述碳包覆可列举为气相包碳和/或固相包碳。
在一些实施方式中，本公开的碳包覆采用气相包碳的方式，具体方法包括：将上述烧成物在保护性气氛下升温至600℃-1000℃，通入有机碳源气体，保温0.5h-10h后冷却。该有机碳源气体可选为烃类(如烷烃、环烷烃、烯烃、炔烃和芳香烃等)，可以如甲烷、乙烯、乙炔和苯中的至少一种。
可选的，气相包碳的方式中热处理的温度具体可以为例如650℃-950℃、750℃-850℃或780℃-820℃，诸如600℃、700℃、800℃、900℃、1000℃等，热处理的保温时间具体可以为例如1.0h-9.0h、3.0h-7.0h或5.0h-6.0h，诸如0.5h、1.5h、2.5h、3.5h、4.5h、5.5h、6.5h、7.5h、8.5h、9.5h、10h等，或任意两个端点值之间的区间值，在此不做限定。可选的，热处理的温度可以为700-900℃，热处理的保温时间可以为3-9h。
在一些实施方式中，本公开的碳包覆采用固相包碳的方式，具体方法包括：将上述烧成物与碳源融合0.5h以上后，将得到的碳混合物在600℃-1000℃下碳化2h-6h，冷却。该碳源可选包括聚烯烃、树脂类、橡胶类、糖类(如葡萄糖、蔗糖、淀粉和纤维素等)、有机酸和沥青中的至少一种。
可选的，固相包碳的方式中热处理的温度具体可以为例如650℃-950℃、710℃-880℃或750℃-810℃，诸如600℃、700℃、800℃、900℃、1000℃等，热处理的保温时间具体可以为2h、3h、4h、5h、6h等，或任意两个端点值之间的区间值，在此不做限定。可选的，热处理的温度可以为700℃-900℃，热处理的保温时间可以为3h-5h。
上述方案中，融合可选地在融合机中进行，融合机转速为500r/min-3000r/min。
可选的，融合机转速具体可以为例如900r/min-2600r/min、1100r/min-2200r/min或1400r/min-1800r/min，诸如500r/min、800r/min、1000r/min、1500r/min、2000r/min、2500r/min、3000r/min等，或任意两个端点值之间的区间值，在此不做限定。可选的，融合机转速可以为1000-3000r/min。
融合机的刀具间隙宽度可根据需要进行选取，例如为0.5cm。
上述碳包覆方式中的保护气氛可选为氦气、氖气、氩气和氮气中的至少一种。
在一些实施方式中，制备粉状负极材料的方法还包括：将粉体化的硅基活性材料进行聚合物包覆，或者将粉体化的硅基活性材料采用碳材料进行碳包覆后，再进行聚合物包覆得到粉状负极材料。
在一些实施方式中，聚合物包覆方法包括以下步骤：
将柔性聚合物溶解于溶剂中，得到柔性聚合物溶液；
在搅拌的条件下，向柔性聚合物溶液中加入导电材料，导电材料包含鳞片石墨和纳米碳类材料，得到混合包覆液；
向混合包覆液中加入反溶剂，搅拌，得到过饱和化后的混合包覆液；
在搅拌的条件下，向过饱和化后的混合包覆液中加入硅基活性物质，搅拌，分离，得到负极材料前驱体；及
对负极材料前驱体进行热处理，得到粉状负极材料。
在一些实施方式中，柔性聚合物上含有热交联型官能团，热交联型官能团包括环氧基、羧基、羟基、氨基、双键和三键中的至少一种。
在一些实施方式中，溶剂包括水、甲醇、乙醇、聚吡咯烷酮、异丙醇、丙酮、石油醚、四氢呋喃、乙酸乙酯、N，N-二甲基乙酰胺、N，N-二甲基甲酰胺、正己烷和卤代烃中的至少一种。
在一些实施方式中，反溶剂包括柔性聚合物的不良溶剂。
在一些实施方式中，反溶剂包括甲醇、乙醇、聚吡咯烷酮、异丙醇、丙酮、石油醚、四氢呋喃、乙酸乙酯、N，N-二甲基乙酰胺、N，N-二甲基甲酰胺、正己烷和卤代烃中的至少一种。
在一些实施方式中，热处理的温度为100℃-400℃，热处理的时间为2h-12h。
可选地，热处理的温度可以为例如140℃-360℃、180℃-280℃或220℃-260℃，诸如100℃、120℃、150℃、180℃、200℃、220℃、250℃、280℃、300℃、320℃、350℃、380℃或400℃等，或任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。热处理的时间可以为例如4.5h-10.5h、6.5h-9.5h或7.5h-8.5h，诸如2h、3h、4h、5h、6h、7h、8h、9h、10h、11h或12h等，或任意两个端点值之间的区间值，当然也可以是上述范围内的其他值，在此不做限定。
在一些实施方式中，制备粉状负极材料的方法还包括：将粉体化的硅基活性材料采用掺杂材料进行掺杂后得到粉状负极材料。
在一些实施方式中，掺杂材料包括碱金属、碱土金属、碱金属氧化物和碱土金属氧化物中的至少一种。
在一些实施方式中，掺杂材料的占负极材料的重量百分比b满足：0＜b≤20％。
可选地，碱金属可以选自锂、钠或钾中的至少一种；碱土金属可以选自镁、钙、锶或钡中的至少一种；碱金属氧化物可以选自氧化锂、氧化钠或氧化钾中的至少一种；碱土金属氧化物可以选自氧化镁、氧化钙、氧化锶、氧化钡中的至少一种。掺杂材料占负极材料的重量百分比b可以为1％、3％、5％、8％、10％、12％、15％、18％或20％等，当然也可以是上述范围内的其他值，在此不做限定。不受理论的约束，通过在负极材料中掺杂金属材料，能够提高硅基活性材料的本征电导率，进一步通过对掺杂材料种类和含量的选择，能够更有效地提高硅基活性材料的电导率。需要说明的是，将粉体化的硅基活性材料采用掺杂材料进行掺杂可以在碳包覆之前进行，也可以在碳包覆之后进行。
本公开一实施方式还提供一种锂离子电池，锂离子电池包括上述负极材料或由上述的制备方法制备的锂离子电池负极材料。
本公开提供了一种负极材料及其制备方法和锂离子电池，解决了现有硅基材料在电池负极极片中材料颗粒不均匀性以及导电性能较差、循环稳定性和倍率性能较差等问题。
本公开提供的一种负极材料通过调整负极材料粒径分布的峰值系数A满足：0＜A≤3，可以使得负极材料的粒度两侧尾端分布更集中，不会出现与粒径中值大小相差过大的颗粒。通过对粒径分布的峰值系数A进行合理选择，能保证负极材料各个颗粒的一致性，使得负极材料调浆涂布时，提高浆料的稳定性，粘结剂和导电剂在不同颗粒表面的分布一致性越好，从而使得涂布后的极片一致性好，不同颗粒在充放电过程中的膨胀收缩的一致性高，不会因为极片局部颗粒膨胀收缩不均衡导致极片容易被破坏、电池的循环性能劣化和电池的膨胀增加，最终使电池的性能一致性高，并且因为避免了材料颗粒的粒度大的差异性，使得导电剂在各个材料颗粒都能均匀有效的附着，提升了电池的倍率性能。通过对负极材料中硅基活性材料的特殊限定，能使制备的负极材料具有理想的高比容量。
此外，当负极材料包含包覆层时，负极材料的粒径分布的峰值系数A满足：0＜A≤3，可以使得负极材料所包含的包覆层，诸如柔性聚合物在每个颗粒上的包覆层厚度一致性好，使得柔性聚合物对材料充放电过程中的体积变化的缓冲效果更佳，提升了材料的循环性能，降低了材料的膨胀。
此外，本公开通过选择负极材料粒径分布的分选系数B满足：0＜B≤3，能够保证负极材料的粒度在粒度分布曲线的中间段(两侧之间)的分布集中，由此使得负极材料在与粘结剂制成极片时，进而使得粘结剂均匀一致地分布，提高了极片的剥离强度，有利于极片构建稳定和完整的导电网络。
另外，本公开通过对分选系数B和峰值系数A的比值B/A的具体限定，能够更有效地避免硅基活性材料颗粒的团聚，从而有效使得负极材料有效发挥电池的高性能。
应当理解的是，以上的一般描述和后文的细节描述仅是示例性的，并不能限制本公开。
实施例
下面分多个实施例对本公开实施例进行进一次的说明。其中，本公开实施例不限定于以下的具体实施例。在保护范围内，可以适当的进行变更实施。
实施例1
一种锂离子电池负极材料的制备方法如图1所示，包括如下步骤S10至步骤S30：
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为100kW，球磨机的转速v1为800rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为55Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为2.00，峰值系数A为1.80，B/A＝1.11。
实施例2
一种锂离子电池负极材料的制备方法包括如下步骤S10至步骤S30：
步骤S10，取1kg Si块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节Si粉体的D50在5μm左右；破碎机的破碎功率p为100kW，球磨机的转速v1为800rpm。
步骤S20，将步骤S10得到的Si粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为6.7％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为65Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为1.50，峰值系数A为1.50，B/A＝1.00。
实施例3
一种锂离子电池负极材料的制备方法包括如下步骤S10至步骤S30：
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为100kW，球磨机的转速v1为800rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为6.8％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为35Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为3.00，峰值系数A为1.50，B/A＝2.00
实施例4
一种锂离子电池负极材料的制备方法包括如下步骤S10至步骤S30：
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为70kW，球磨机的转速v1为1100rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7.1％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为70Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为1.20，峰值系数A为3.01，B/A＝0.40。
实施例5
一种锂离子电池负极材料的制备方法包括如下步骤S10至步骤S30：
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为150kW，球磨机的转速v1为600rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7.1％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为40Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为2.50，峰值系数A为0.50，B/A＝5.00。
实施例6
一种锂离子电池负极材料的制备方法包括如下步骤S10至步骤S30：
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为150kW，球磨机的转速v1为650rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7.3％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为46Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为2.10，峰值系数A为0.70，B/A＝3.00。
实施例7
一种锂离子电池负极材料的制备方法包括如下步骤S10至步骤S30：
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为110kW，球磨机的转速v1为750rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为75Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为1.01，峰值系数A为1.20，B/A＝0.84。
实施例8
一种锂离子电池负极材料的制备方法包括如下步骤S10至步骤S30：
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为120kW，球磨机的转速v1为700rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7.2％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为60Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为1.60，峰值系数A为1.00，B/A＝1.60。
实施例9
一种锂离子电池负极材料的制备方法包括如下步骤S10至步骤S30：
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在20μm左右；破碎机的破碎功率p为90kW，球磨机的转速v1为400rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为6.9％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为58Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为1.80，峰值系数A为0.80，B/A＝2.24。
实施例10
一种锂离子电池负极材料的制备方法包括如下步骤S10至步骤S40：
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在20μm左右；破碎机的破碎功率p为90kW，球磨机的转速v1为600rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7.1％。
步骤S30，将步骤S20进行碳包覆后的SiO粉体进行掺杂材料掺杂；掺杂材料为MgO，掺杂材料占负极材料的重量百分比b为5％。
步骤S40，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的，引风机频率f为56Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为1.91，峰值系数A为1.00，B/A＝1.91。
实施例11
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为100kW，球磨机的转速v1为800rpm。
步骤S20，使用气流分级机对步骤S10得到的粉末进行粒径调整，分级机的引风机频率f为58Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为2.20，峰值系数A为1.89，B/A＝1.16。
实施例12
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在20μm左右；破碎机的破碎功率p为90kW，球磨机的转速v1为600rpm。
步骤S20，将步骤S10进行碳包覆后的SiO粉体进行掺杂材料掺杂；掺杂材料为MgO，掺杂材料占负极材料的重量百分比b为5％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的，引风机频率f为55Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为1.76，峰值系数A为1.22，B/A＝1.44。
实施例13
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在20μm左右；破碎机的破碎功率p为90kW，球磨机的转速v1为600rpm。
步骤S20，将步骤S10进行碳包覆后的SiO粉体进行掺杂材料掺杂；掺杂材料为MgO，掺杂材料占负极材料的重量百分比b为5％。
步骤S30，将步骤S20得到的粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7.3％。
步骤S40，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的，引风机频率f为56Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为2.17，峰值系数A为1.22，B/A＝1.78。
实施例14
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为100kW，球磨机的转速v1为800rpm。
步骤S20，将步骤S10得到的SiO粉体使用融合机进行处理，融合机转速1000r/min，处理时间6h；
步骤S30，将步骤S20得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为6.9％。
步骤S40，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为55Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为1.95，峰值系数A为1.75，B/A＝1.11，球形度为0.79。
实施例15
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为100kW，球磨机的转速v1为800rpm。
步骤S20，将步骤S10得到的SiO粉体使用融合机进行处理，融合机转速1000r/min，处理时间6.2h；
步骤S30，将步骤S20得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7.0％。
步骤S40，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为55Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为1.90，峰值系数A为1.67，B/A＝1.14，球形度为0.82。
实施例16
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为100kW，球磨机的转速v1为800rpm。
步骤S20，将步骤S10得到的SiO粉体使用融合机进行处理，融合机转速2500r/min，处理时间8.5h；
步骤S30，将步骤S20得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7.1％。
步骤S40，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为55Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为1.93，峰值系数A为1.62，B/A＝1.19，球形度为0.91。
实施例17
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为100kW，球磨机的转速v1为800rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为55Hz，得到粒度调整后的负极材料。
步骤S40，将4g聚丙烯酸溶解于100g蒸馏水中，在温度为40℃下充分溶解后，在搅拌的条件下加入1g碳纳米纤维，搅拌2小时后加入200g乙醇，继续搅拌0.5小时，再将90g步骤S30得到的在搅拌下加入其中，在温度为60℃下搅拌2小时后降至室温，抽滤分离出材料，然后置于180℃的干燥箱中热处理4小时，冷却后取出得到相应的聚丙烯酸和碳纳米纤 维包覆后的SiOx负极材料，得到的负极材料粒径分布的分选系数B为2.00，峰值系数A为1.78，B/A＝1.12。
实施例18
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为110kW，球磨机的转速v1为750rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为20Hz，得到粒度调整后的负极材料。
步骤S40，将4g聚丙烯酸溶解于100g蒸馏水中，在温度为40℃下充分溶解后，在搅拌的条件下加入1g碳纳米纤维，搅拌2小时后加入200g乙醇，继续搅拌0.5小时，再将90g步骤S30得到的在搅拌下加入其中，在温度为60℃下搅拌2小时后降至室温，抽滤分离出材料，然后置于180℃的干燥箱中热处理4小时，冷却后取出得到相应的聚丙烯酸和碳纳米纤维包覆后的SiOx负极材料，得到的负极材料粒径分布的分选系数B为2.88，峰值系数A为1.27，B/A＝2.27。
实施例19
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在20μm左右；破碎机的破碎功率p为90kW，球磨机的转速v1为600rpm。
步骤S20，将步骤S10进行碳包覆后的SiO粉体进行掺杂材料掺杂；掺杂材料为Li2O，掺杂材料占负极材料的重量百分比b为4.5％。
步骤S30，将步骤S20得到的粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7.2％。
步骤S40，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的，引风机频率f为56Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为2.19，峰值系数A为1.19，B/A＝1.84。
实施例20
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为110kW，球磨机的转速v1为750rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为20Hz，得到粒度调整后的负极材料。
步骤S40，将4g海藻酸钠(即海藻酸的衍生物)溶解于100g蒸馏水中，在温度为40℃下充分溶解后，在搅拌的条件下加入1g导电石墨，搅拌2小时后加入200g乙醇，继续搅拌0.5小时，再将90g步骤S30得到的在搅拌下加入其中，在温度为60℃下搅拌2小时后降至室温，抽滤分离出材料，然后置于180℃的干燥箱中热处理4小时，冷却后取出得到相应的海藻酸钠和导电石墨包覆后的SiOx负极材料，得到的负极材料粒径分布的分选系数B为2.90，峰值系数A为1.30，B/A＝2.23。
实施例21
一种锂离子电池负极材料的制备方法包括如下步骤S10至步骤S30：
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为100W，球磨机的转速v1为1000rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为6.9％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为110Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为3.77，峰值系数A为0.71，B/A＝5.31。
实施例22
一种锂离子电池负极材料的制备方法包括如下步骤S10至步骤S30：
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为110kW，球磨机的转速v1为750rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的引风机频率f为10Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为3.19，峰值系数A为1.30，B/A＝2.45。
实施例23
一种锂离子电池负极材料的制备方法包括如下步骤S10至步骤S30：
步骤S10，取1kg Si块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节Si粉体的D50在5μm左右；破碎机的破碎功率p为150kW，球磨机的转速v1为550rpm。
步骤S20，将步骤S10得到的Si粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为6.9％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，分级机的，引风机频率f为53Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为2.42，峰值系数A为0.46，B/A＝5.24。
对比例1
一种锂离子电池负极材料的制备方法包括如下步骤S10至步骤S30：
步骤S10，取1kg SiO块体材料备用，使用破碎机和球磨机对块体材料进行粉体化，调节SiO粉体的D50在5μm左右；破碎机的破碎功率p为150kW，球磨机的转速v1为550rpm。
步骤S20，将步骤S10得到的SiO粉体采用碳材料进行碳包覆；碳材料占负极材料的重量百分比a为7.1％。
步骤S30，使用气流分级机对步骤S20得到的粉末进行粒径调整，引风机频率f为65Hz，得到最终的负极材料。负极材料粒径分布的分选系数B为1.63，峰值系数A为3.04，B/A＝0.54。
效果分析
对上述实施例及对比例中得到的负极材料进行如下性能测试：
(1)粒度分布测试：使用马尔文2000粒度仪对材料粒度分布进行测试，设置为折射率2.42，遮光度8％-20％，分散剂为水；
(2)首次容量效率测试：a、锂离子电池的制备：将制备得到的负极材料：导电炭黑：CMC(羧甲基纤维素)/SBR(丁苯橡胶)＝75:15:10的比例涂覆在铜箔上，制备成负极片，金属锂片作为对电极，PP/PE作为隔膜，制成纽扣电池；b、采用蓝电新威5V/10mA型电池测试仪测试电池的电化学性能，电压为1.5V，电流为0.1C，首次效率＝首次充电比容量/首次放电比容量。
(3)循环性能测试：a、锂离子电池的制备：将制备得到的负极材料与石墨按15:85的比例混合得到负极活性物质按负极活性物质：导电炭黑：CMC：SBR＝92:4:2:2的比例涂覆在铜箔上，制备成负极片，金属锂片作为对电极，PP/PE作为隔膜，制成纽扣电池；b、采用蓝电新威5V/10mA型电池测试仪测试电池的电化学性能，电压为1.5V，电流为0.1C，50周循环保持率＝第50次放电比容量/首次放电比容量。
(4)膨胀性能测试：a、锂离子电池的制备：将制备得到的负极材料与石墨按15:85的比例混合得到负极活性物质，按负极活性物质：导电炭黑：CMC：SBR＝92:4:2:2的比例涂覆在铜箔上，制备成负极片，并使用千分尺测量负极片的厚度，记为L1，金属锂片作为对电极，PP/PE作为隔膜，制成纽扣电池；b、采用蓝电新威5V/10mA型电池测试仪测试电池的电化学性能，电压为1.5V，电流分别为0.1C。50周循环后，将电池拆开，使用千分尺测量负极片的厚度，记为L2，50周极片膨胀率＝(L2-铜箔厚度)/(L1-铜箔厚度)*100％。
(5)电池一致性测试：按照(2)和(3)方法制备，制备10只相同的电池，对比10只电池的50周容量保持率和50周极片膨胀率的一致性。一致性由10组50周容量保持率和50周极片膨胀率的相对标准偏差(RSD)表示。
(6)扫描电镜测试：使用S4800扫描电子显微镜对材料进行测试，观察微观颗粒状态。
(7)wadell球形度测试：使用激光粒度仪测得粒径分布，得到每个粒度范围内的等效体积径。用该等效体积径作为该极小粒度分布范围内的所有球体的粒径，并将该范围内的所有颗粒等效为理想球体，算出每个粒径分布范围内比表面积，接着使用体积比％加权得到与所有颗粒等体积的球的比表面面积，从而求得等离子体制备的球形颗粒的球形度＝计算得到的与颗粒等体积的球的表面面积/比表面积仪测试得到的颗粒的比表面积。
(8)倍率及剥离强度测试：
a、锂离子电池的制备：将上述实施例和对比例制备得到的复合材料分别与石墨按15：85的质量比混合得到负极活性物质，然后按负极活性物质、导电炭黑、CMC和SBR的质量比为92：4：2：2的比例混合均匀，涂覆在铜箔上，制备成负极片，使用百格刀法对负极片进行剥离强度测试。
b、另取负极片，以金属锂片作为正极片，PP/PE作为隔膜，制成纽扣电池
c、采用蓝电新威5V/10mA型电池测试仪测试，电压为1.5V，电流分别为0.1C和3C，3C/0.1C＝3C电流的放电比容量/0.1C电流放电比容量。
电池测试和实验过程记录数据如下表1所示，实施例1、13、17、22和对比例1的粒度分布结果分别如图2至图5以及图6所示，实施例1、13、17、22和对比例1的扫描电镜结果分别如图7至图10以及图11所示。
表1实施例和对比例实验数据的对比表


表2实施例和对比例实验数据的负极材料粒径分布表

如图2-5的结果可以看出，通过调整包覆有碳层的硅基活性材料的粒度，通过对粒径的分选系数B和峰值系数A进行选择，得到粒径分布合适的负极材料，能保证负极材料颗粒的一致性。由上述表1可以看出，采用本公开的负极材料制备的锂离子电池具有优异的容量效率、循环性能、充放电性能和膨胀性能，还具有高的剥离强度，能有效地提升锂离子电池的性能。通过比较实施例21-23和对比例1，可以看出，本公开通过对粒径分布的峰值系数A进行选择，可以得到粒径分布相对合适的负极材料，使得负极材料的性能得到提高，特别是提高了负极材料的倍率性能。此外，通过比较实施例1-20和对比例1，可以看出本公开通过对峰值系数A和粒径的分选系数B进行选择，并对B/A进行选择，可以使得负极材料的粒度分布更加集中，而且进一步提高了负极材料的50周容量保持率、倍率性能以及剥离强度，进一步降低了负极材料的膨胀率。
以上所述仅为本公开的可选的实施例而已，并不用于限制本公开，对于本领域的技术人员来说，本公开可以有各种更改和变化。凡在本公开的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本公开的保护范围之内。
工业实用性
本公开提供了一种负极材料及其制备方法和锂离子电池，本公开的负极材料通过对负极材料粒径分布的峰值系数A的限定，能保证负极材料颗粒的一致性，从而使得涂布后的极片一致性好，进而使电池的性能一致性高，提升电池性能；此外通过对分选系数B、二者的比值B/A的进一步限定，可以使得负极材料具有更好的粒度分布和更高的电池性能，因此具备优异的实用性能和广泛的应用前景。

Claims (14)

  1. 一种负极材料，其特征在于，所述负极材料的粒径分布的峰值系数A满足：0＜A≤3；其中，A＝(D95-D5)/[2.5*(D75-D25)]，D95、D5、D75、D25分别代表累积曲线上体积百分含量达到95％、5％、75％、25％时所述负极材料的粒径；
    所述负极材料包括硅基活性材料，所述硅基活性材料包括SiOx、SiOx/C、SiOx/M、Si、Si/C和Si/M中的至少一种，其中，0＜x≤2，所述M包括金属、非金属、金属氧化物以及非金属氧化物中的至少一种。
  2. 如权利要求1所述的负极材料，其特征在于，所述负极材料包括如下特征(1)-(12)的至少一个：
    (1)所述负极材料的粒径分布为：0＜D5≤65μm，0＜D25≤69μm，0＜D75≤75μm，0＜D95≤79μm；
    (2)所述负极材料的红外光谱测试在波数为3200cm-1-3600cm-1范围内存在包峰；
    (3)所述负极材料的wadell球形度≥0.8；
    (4)所述硅基活性材料的粒径D50大于0μm，且小于等于80μm；
    (5)所述硅基活性材料的比表面积为0-10m2/g，且不为0；
    (6)所述硅基活性材料的振实密度为0.5g/m3～2g/m3；
    (7)所述负极材料还包括掺杂在所述硅基活性材料中的掺杂材料；
    (8)所述负极材料还包括掺杂在所述硅基活性材料中的掺杂材料，所述掺杂材料包括碱金属、碱土金属、碱金属氧化物和碱土金属氧化物中的至少一种；
    (9)所述负极材料还包括掺杂在所述硅基活性材料中的掺杂材料，所述掺杂材料占所述负极材料的重量百分比b满足：0＜b≤20％；
    (10)所述负极材料的粒径分布的分选系数B满足：0＜B≤3，其中，B＝(D84-D16)/4+(D95-D5)/6.6，D84、D16、D95、D5分别代表累积曲线上体积百分含量达到84％、16％、95％、5％时所述负极材料的粒径；
    (11)所述负极材料的粒径分布为：0＜D5≤65μm，0＜D16≤67μm，0＜D84≤77μm，0＜D95≤79μm；
    (12)所述负极材料的粒径分布的分选系数B和所述峰值系数A满足：0＜B/A≤5。
  3. 如权利要求1所述的负极材料，其特征在于，所述负极材料还包括位于所述硅基活性材料表面的包覆层，所述包覆层包括柔性聚合物和导电材料中的至少一种。
  4. 根据权利要求3所述的负极材料，所述负极材料还包括如下特征(1)-(13)的至少一个：
    (1)所述导电材料包括鳞片石墨和纳米碳类材料；
    (2)所述柔性聚合物包括天然的柔性聚合物和/或合成的柔性聚合物；
    (3)所述柔性聚合物包括聚烯烃及其衍生物、聚乙烯醇及其衍生物、聚丙烯酸及其衍生物、聚酰胺及其衍生物、羧甲基纤维素及其衍生物、海藻酸及其衍生物和聚碳酸酯及其衍生物中的至少一种；
    (4)所述柔性聚合物的重均分子量为2000-1000000；
    (5)所述柔性聚合物上含有热交联型官能团，所述热交联型官能团包括环氧基、羧基、羟基、氨基、双键和叁键中的至少一种；
    (6)所述鳞片石墨包括天然鳞片石墨和/或人造鳞片石墨；
    (7)所述纳米碳类材料包括导电石墨、石墨烯、碳纳米管和碳纳米纤维中的至少一种；
    (8)以所述负极材料的总质量为100％计，所述柔性聚合物的质量百分比为0-10％，且不包含0；
    (9)以所述负极材料的总质量为100％计，所述鳞片石墨的质量百分比为0-20％，且不包含0；
    (10)以所述负极材料的总质量为100％计，所述纳米碳类材料的质量百分比为0-5％，且不包含0；
    (11)所述包覆层的厚度为10nm～5000nm；
    (12)所述包覆层在所述负极材料中的质量占比为0-20％，且不包含0；
    (13)所述包覆层在所述负极材料中的质量占比为2％～10％。
  5. 一种负极材料的制备方法，其特征在于，包括如下步骤：
    制备粉状负极材料；
    对制备的所述粉状负极材料进行粒径调整，以得到负极材料；所述负极材料的粒径分布的峰值系数A满足：0＜A≤3；其中，A＝(D95-D5)/[2.5*(D75-D25)]，D95、D5、D75、D25分别代表累积曲线上体积百分含量达到95％、5％、75％、25％时所述负极材料的粒径；
    所述负极材料包括硅基活性材料，所述硅基活性材料包括SiOx、SiOx/C、SiOx/M、Si、Si/C和Si/M中的至少一种，其中，0＜x≤2，所述M包括金属、非金属、金属氧化物以及非金属氧化物中的至少一种。
  6. 如权利要求5所述的制备方法，其特征在于，所述负极材料的粒径分布的分选系数B满足：0＜B≤3，其中，B＝(D84-D16)/4+(D95-D5)/6.6，D84、D16、D95、D5分别代表累积曲线上体积百分含量达到84％、16％、95％、5％时的粒径。
  7. 如权利要求6所述的制备方法，其特征在于，制备所述粉状负极材料的方法包括：将所述硅基活性材料粉体化得到所述粉状负极材料。
  8. 如权利要求7所述的制备方法，其特征在于，所述制备方法至少满足以下特征(1)～(6)中的一种：
    (1)所述粉体化的方法包括破碎和球磨；
    (2)所述破碎采用的装置包括破碎机，所述破碎机的破碎功率p满足：0＜p≤300kW；
    (3)所述球磨采用的装置包括球磨机，所述球磨机的转速v1满足：0＜v1≤1500rpm；
    (4)所述粒径调整采用的装置包括分级机；所述分级机的引风机频率f满足：0＜f≤100Hz；
    (5)所述分选系数B和所述峰值系数A满足：0＜B/A≤5；
    (6)所述硅基活性材料的粒径D50大于0μm，且小于等于80μm。
  9. 如权利要求8所述的制备方法，其特征在于，制备所述粉状负极材料的方法还包括：将所述粉体化的硅基活性材料采用碳材料进行碳包覆后得到所述粉状负极材料；所述碳材料占所述负极材料的重量百分比a满足：0＜a≤15％。
  10. 如权利要求8或9所述的制备方法，其特征在于，制备所述粉状负极材料的方法还包括：将所述粉体化的硅基活性材料进行聚合物包覆或者将粉体化的所述硅基活性材料采用碳材料进行碳包覆后，再得到所述粉状负极材料。
  11. 如权利要求10所述的制备方法，其特征在于，所述聚合物包覆方法包括以下步骤：
    将柔性聚合物溶解于溶剂中，得到柔性聚合物溶液；
    在搅拌的条件下，向所述柔性聚合物溶液中加入导电材料，所述导电材料包含鳞片石墨和纳米碳类材料，得到混合包覆液；
    向所述混合包覆液中加入反溶剂，搅拌，得到过饱和化后的混合包覆液；
    在搅拌的条件下，向所述过饱和化后的混合包覆液中加入硅基活性物质，搅拌，分离，得到负极材料前驱体；及
    对所述负极材料前驱体进行热处理，得到所述粉状负极材料。
  12. 根据权利要求11所述的制备方法，其特征在于，所述制备方法包括以下特征(1)～(6)中的至少一种：
    (1)所述柔性聚合物上含有热交联型官能团，所述热交联型官能团包括环氧基、羧基、羟基、氨基、双键和叁键中的至少一种；
    (2)所述溶剂包括水、甲醇、乙醇、聚吡咯烷酮、异丙醇、丙酮、石油醚、四氢呋喃、乙酸乙酯、N，N-二甲基乙酰胺、N，N-二甲基甲酰胺、正己烷和卤代烃中的至少一种；
    (3)所述反溶剂包括柔性聚合物的不良溶剂；
    (4)所述反溶剂包括甲醇、乙醇、聚吡咯烷酮、异丙醇、丙酮、石油醚、四氢呋喃、乙酸乙酯、N，N-二甲基乙酰胺、N，N-二甲基甲酰胺、正己烷和卤代烃中的至少一种；
    (5)所述热处理的温度为100℃-400℃；
    (6)所述热处理的时间为2h-12h。
  13. 如权利要求8所述的制备方法，其特征在于，制备所述粉状负极材料的方法还包括：将所述粉体化的硅基活性材料采用掺杂材料进行掺杂后得到所述粉状负极材料；
    所述制备方法至少满足以下特征中的一种：
    (1)所述掺杂材料包括碱金属、碱土金属、碱金属氧化物和碱土金属氧化物中的至少一种；
    (2)所述掺杂材料占所述负极材料的重量百分比b满足：0＜b≤20％。
  14. 一种锂离子电池，其特征在于，包括权利要求1-4任一项所述的负极材料或由权利要求5-13任一项所述的制备方法制备的负极材料。
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