WO2021017827A1 - 负极活性材料、其制备方法、及其相关的二次电池、电池模块、电池包和装置 - Google Patents

负极活性材料、其制备方法、及其相关的二次电池、电池模块、电池包和装置 Download PDF

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WO2021017827A1
WO2021017827A1 PCT/CN2020/102062 CN2020102062W WO2021017827A1 WO 2021017827 A1 WO2021017827 A1 WO 2021017827A1 CN 2020102062 W CN2020102062 W CN 2020102062W WO 2021017827 A1 WO2021017827 A1 WO 2021017827A1
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active material
negative electrode
electrode active
optionally
negative
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PCT/CN2020/102062
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English (en)
French (fr)
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梁成都
赵玉珍
官英杰
温严
黄起森
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宁德时代新能源科技股份有限公司
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Priority to ES20846942T priority Critical patent/ES2930048T3/es
Priority to KR1020217030667A priority patent/KR102499598B1/ko
Priority to JP2021554734A priority patent/JP7162148B2/ja
Priority to EP20846942.9A priority patent/EP3944371B1/en
Publication of WO2021017827A1 publication Critical patent/WO2021017827A1/zh
Priority to US17/586,754 priority patent/US11476457B2/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • 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
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • 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
    • 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
    • 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
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/387—Tin or alloys based on tin
    • 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
    • H01M4/58—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
    • 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
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • 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

  • This application belongs to the technical field of energy storage devices, and specifically relates to a negative electrode active material, a preparation method thereof, and related secondary batteries, battery modules, battery packs and devices.
  • the first aspect of the application provides a negative active material, which includes a core material and a polymer-modified coating layer on at least a part of the surface; the core material includes one or more of silicon-based materials and tin-based materials ; the coating layer comprises elemental sulfur and carbon; said negative electrode active material in the Raman spectrum, the Raman shift is 900cm -1 ⁇ 960cm -1, 1300cm -1 ⁇ 1380cm -1 and 1520cm -1 ⁇ 1590cm
  • the position of -1 has a scattering peak, and the peak intensity I 1 of the scattering peak at the Raman shift of 900 cm -1 to 960 cm -1 and the peak of the scattering peak at the Raman shift of 1520 cm -1 to 1590 cm -1
  • the intensities I G satisfy 0.2 ⁇ I 1 /I G ⁇ 0.8.
  • the negative active material provided in the present application includes a core material and a polymer modified coating layer on at least a part of the surface thereof;
  • the core material includes one or more of silicon-based materials and tin-based materials ;
  • the coating layer comprises elemental sulfur and carbon, and the displacement of 900cm -1 ⁇ 960cm -1 in a Raman, 1300cm ⁇ 1520cm -1 1380cm -1 position -1 ⁇ 1590cm -1 and the scattering peak respectively, while the displacement of the peak intensity of 900cm -1 ⁇ 960cm -1 scattering peaks satisfies a preset position with the displacement relationship between the peak intensity of the scattered peak 1520cm -1 ⁇ 1590cm -1 in the Raman Raman position, such that the negative electrode active
  • the material has high ion conductivity and electronic conductivity, so the first coulombic efficiency and cycle life of the negative electrode active material are significantly improved, so that the first coulombic efficiency and cycle performance of
  • 0.22 ⁇ I 1 /I G ⁇ 0.6 can be satisfied between I 1 and I G.
  • the relationship between I 1 and I G of the negative active material can further improve the rate performance and cycle life of the battery, and further improve the first coulombic efficiency of the battery.
  • the negative electrode active material a Raman shift of Raman spectrum peak intensity of 1300cm -1 ⁇ 1380cm -1 scattering peak position is I D, I D between the meet and I G 1.05 ⁇ I D /I G ⁇ 1.50; optional, 1.1 ⁇ I D /I G ⁇ 1.45.
  • I D I G 1.05 ⁇ I D /I G ⁇ 1.50
  • I G 1.05 ⁇ I D /I G ⁇ 1.50
  • the negative active material in the Raman spectrum is a Raman shift of 1300cm -1 1380cm ⁇ -1 scattering peak half-width position of 120cm -1 ⁇ 160cm -1, optionally 128cm - 1 ⁇ 152cm -1 .
  • the half-width of the scattering peak at the Raman shift of 1300 cm -1 to 1380 cm - 1 is within the range, which can further improve the cycle performance of the secondary battery.
  • the mass percentage of sulfur in the negative electrode active material may be 0.5% to 3%, for example, 0.8% to 1.5%.
  • the content of sulfur in the negative electrode active material is within the above range, which can improve the cycle performance and energy density of the secondary battery.
  • the mass percentage of the carbon element in the negative active material can be selected to be 0.1% to 4%, for example, 0.5% to 3%.
  • the content of the carbon element in the negative electrode active material is within the above range, which can improve the cycle performance and energy density of the secondary battery.
  • the X-ray diffraction spectrum of the negative active material has a diffraction peak at a position where the diffraction angle 2 ⁇ is 19°-27°, and the half-value width is 4°-12°; optionally, The half-width is 5° ⁇ 10°.
  • a negative electrode active material having a diffraction peak in a position where the X-ray diffraction angle 2 ⁇ is 19°-27° and a half-width within the above-mentioned range can further improve the cycle life of the battery.
  • the particle size distribution of the negative electrode active material satisfies: 0.5 ⁇ (D v 90-D v 10)/D v 50 ⁇ 2.5; optionally, 0.8 ⁇ (D v 90-D v 10) /D v 50 ⁇ 2.0.
  • the particle size distribution of the negative electrode active material is within the above range, which can further improve the cycle performance of the battery.
  • the average particle size D v 50 of the negative electrode active material is 2 ⁇ m to 12 ⁇ m, and optionally 4 ⁇ m to 8 ⁇ m. If the D v 50 of the negative electrode active material is within the above range, the cycle performance of the secondary battery can be further improved, and the energy density of the secondary battery can also be improved.
  • the specific surface area of the negative electrode active material is 0.5 m 2 /g to 5 m 2 /g, optionally 0.8 m 2 /g to 3 m 2 /g.
  • the specific surface area of the negative electrode active material is within an appropriate range, which can further improve the cycle performance of the secondary battery while meeting the requirements of the dynamic performance and rate performance of the secondary battery.
  • the tap density of the negative electrode active material is 0.8 g/cm 3 to 1.3 g/cm 3 , optionally 0.9 g/cm 3 to 1.2 g/cm 3 .
  • the tap density of the negative electrode active material is within the above range, which is beneficial to increase the energy density of the secondary battery.
  • the compact density of the negative electrode active material measured under a pressure of 5 tons is 1.2g/cm 3 ⁇ 1.5g/cm 3 , optionally 1.25g/cm 3 ⁇ 1.45g/cm 3 .
  • the compact density of the negative active material measured under a pressure of 49KN is within the above range, which is beneficial to increase the energy density of the secondary battery.
  • the silicon-based material may be selected from one or more of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen compounds, and silicon alloys; optionally, the silicon-based materials It is selected from silicon-oxygen compounds; the tin-based material can be selected from one or more of elemental tin, tin-oxygen compounds, and tin alloys. These materials have a higher gram capacity, which enables the secondary battery using them to obtain higher energy density.
  • the second aspect of the present application provides a method for preparing a negative active material, which includes the following steps:
  • the core material includes one or more of silicon-based materials and tin-based materials
  • the negative electrode active material includes a core material and a polymer modified coating layer on at least a part of the surface thereof, the coating layer contains sulfur and carbon elements, and the Raman spectrum of the negative electrode active material is Raman shift is 900cm -1 ⁇ 960cm -1, 1300cm ⁇ 1520cm position -1 and 1380 cm -1 -1 ⁇ 1590cm -1, respectively, with scattering peaks, and the displacement of 900cm ⁇ 960cm -1 in a Raman scattering at position -1
  • the peak intensity I 1 of the peak and the peak intensity I G of the scattering peak at the position of the Raman shift of 1520 cm -1 to 1590 cm -1 satisfy 0.2 ⁇ I 1 /I G ⁇ 0.8.
  • the negative active material obtained by the preparation method provided in this application includes a core material and a polymer modified coating layer on at least a part of its surface; the core material includes one or more of silicon-based materials and tin-based materials; said cladding layer comprises elemental sulfur and carbon, and the displacement of 900cm -1 ⁇ 960cm -1 in a Raman, 1300cm -1 ⁇ 1380cm -1 and 1520cm - 1 ⁇ 1590cm -1 position of the scattering peak respectively, while Raman shift is 900cm -1 ⁇ scattering peak intensity of the peak position and the displacement 960cm -1 in a Raman scattering peak between peak intensity of 1520cm -1 ⁇ 1590cm -1 satisfies the preset position relationship, so that the negative active material has With higher ion conductivity and electronic conductivity, the first coulombic efficiency and cycle life of the negative electrode active material are significantly improved, so that the first coulombic efficiency and cycle performance of the secondary battery are greatly
  • the polymer includes one or more of polyaniline, polyacetylene, polyacrylonitrile, polystyrene, polyvinyl chloride, and polyethylene.
  • the coating layer based on the polymer can provide effective protection to the core material and improve the electronic conductivity of the negative electrode active material, thereby helping to improve the cycle performance of the secondary battery.
  • the ratio of the mass of the polymer to the volume of the solvent is 0.1 g/L to 10 g/L; optionally, the mass of the polymer
  • the ratio to the volume of the solvent is 1 g/L to 5 g/L.
  • the proper amount of polymer added is beneficial to improve the particle size distribution of the negative electrode active material, wherein the D v 10, D v 50, and D v 99 of the negative electrode active material can be made within an appropriate range, thereby improving the energy of the secondary battery Density and cycle performance.
  • the mass ratio of the core material to the polymer in the mixed slurry is 10 to 200; optionally, the mass ratio of the core material to the polymer in the mixed slurry is 20 to 100.
  • the mass ratio of the core material and the polymer is in an appropriate range, which is beneficial for the secondary battery to have higher energy density and cycle performance.
  • the step of mixing the solid powder and the sulfur powder satisfies: the ratio of the mass of the sulfur powder to the mass of the polymer in the solid powder is 1 to 5; optionally, the sulfur powder The ratio of the mass of the polymer to the mass of the polymer in the solid powder is 2-4.
  • the mass ratio of the sulfur powder to the polymer is within the above range, which is beneficial for the secondary battery to obtain higher cycle performance.
  • the temperature of the heat treatment is 200°C to 450°C; optionally, the temperature of the heat treatment is 300°C to 450°C.
  • the heat treatment temperature within the above range can improve the cycle performance of the secondary battery.
  • the heat treatment time is 2h-8h; optionally, the heat treatment time is 3h-5h.
  • a third aspect of the present application provides a secondary battery, which includes the anode active material according to the first aspect or the anode active material obtained according to the preparation method of the second aspect of the present application.
  • the secondary battery of the present application uses the negative electrode active material of the present application, it can simultaneously take into account higher energy density, first-time coulombic efficiency and cycle performance.
  • a fourth aspect of the present application provides a battery module including the secondary battery according to the third aspect of the present application.
  • a fifth aspect of the present application provides a battery pack including the battery module according to the fourth aspect of the present application.
  • a sixth aspect of the present application provides a device including at least one of the secondary battery according to the third aspect of the present application, the battery module according to the fourth aspect of the present application, or the battery pack according to the fifth aspect of the present application.
  • the battery module, battery pack, and device of the present application include the secondary battery described in the present application, and therefore have at least the same or similar technical effects as the secondary battery.
  • Fig. 1 is a Raman spectrum diagram of a negative active material according to the present application.
  • Fig. 2 is an X-ray diffraction spectrum (XRD) diagram of a negative active material according to the present application.
  • Fig. 3 is a schematic diagram of an embodiment of a secondary battery.
  • Fig. 4 is an exploded view of Fig. 3.
  • Fig. 5 is a schematic diagram of an embodiment of a battery module.
  • Fig. 6 is a schematic diagram of an embodiment of a battery pack.
  • Fig. 7 is an exploded view of Fig. 6.
  • Fig. 8 is a schematic diagram of an embodiment of a device in which a secondary battery is used as a power source.
  • any lower limit may be combined with any upper limit to form an unspecified range; and any lower limit may be combined with other lower limits to form an unspecified range, and any upper limit may be combined with any other upper limit to form an unspecified range.
  • every point or single value between the end points of the range is included in the range. Therefore, each point or single numerical value can be used as its own lower limit or upper limit in combination with any other point or single numerical value or in combination with other lower or upper limits to form an unspecified range.
  • the negative active material includes a core material and a polymer modified coating layer on at least a part of the surface thereof;
  • the core material includes one of a silicon-based material and a tin-based material or more;
  • the coating layer comprises elemental sulfur and carbon;
  • Raman spectroscopy and the negative electrode active material the Raman shift is 900cm -1 ⁇ 960cm -1, 1300cm -1 ⁇ 1380cm -1 and 1520cm -1 ⁇ 1590cm -1 position of the scattering peak respectively (see FIG.
  • the negative active material is a peak intensity of Raman scattering peak displacement of 900cm -1 ⁇ 960cm -1 position and a Raman I 1
  • the peak intensities I G of the scattering peaks with displacements of 1520 cm -1 to 1590 cm -1 satisfy 0.2 ⁇ I 1 /I G ⁇ 0.8.
  • the negative active material of the present application at least a part of the outer surface of the core material is coated with a polymer modified coating layer, which has a good protective effect on the core material, inhibits the side reaction of the electrolyte on the surface of the core material, and ensures the negative electrode activity
  • the material has high capacity and cycle life.
  • the position where the Raman shift is 900 cm -1 to 960 cm -1 has a scattering peak attributed to the SS bond (hereinafter referred to as the SS peak), so that the coating layer has a higher Active ion conduction performance; at the Raman shift of 1300cm -1 ⁇ 1380cm -1 there is a carbon D-band scattering peak (hereinafter referred to as D peak), at the Raman shift of 1520cm -1 ⁇ 1590cm -1
  • D peak carbon D-band scattering peak
  • the scattering peak in the G band of carbon (hereinafter referred to as the G peak) makes the coating layer have higher electronic conductivity.
  • the SS bond breaks and combines with the active ions to carry out ion migration, and has a high migration efficiency; while the active ions are released during the battery discharge process, and the SS bond re-bonds.
  • the structure of the carbon-based skeleton remains unchanged and complete, ensuring the protective effect of the coating layer on the silicon oxide compound.
  • the negative electrode active material in the Raman spectrum the peak intensity between the peak intensity I 1 and the SS peak peak I G G satisfies 0.2 ⁇ I 1 / I G ⁇ 0.8.
  • the inventor found that the peak intensity of the SS peak and the peak intensity of the G peak satisfy the above-mentioned preset relationship, and the ion-conducting performance and the conductor performance of the negative electrode active material are greatly improved. Therefore, the negative electrode active material has high conductivity of active ions and electrons, which is beneficial to the capacity of the negative electrode active material and the capacity retention rate during the cycle. It can also reduce the polarization of the battery and reduce the irreversible capacity of the battery. , Thereby significantly improving the first coulombic efficiency and cycle performance of the secondary battery.
  • the use of the negative electrode active material of the present application enables the secondary battery to simultaneously take into account higher first coulombic efficiency, cycle performance and energy density.
  • the core material includes one or more of silicon-based materials and tin-based materials.
  • the silicon-based material is selected from one or more of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen compounds, and silicon alloys.
  • the silicon-based material is selected from silicon oxygen compounds.
  • the theoretical gram capacity of the silicon-oxygen compound is about 7 times that of graphite, and compared with the simple substance of silicon, the volume expansion during charging is greatly reduced, and the cycle stability of the battery is greatly improved.
  • the tin-based material can be selected from one or more of elemental tin, tin oxide compounds, and tin alloys.
  • SS peak intensity peak I and peak intensity 1 G I G peak ratio I 1 / I G can ⁇ 0.8, ⁇ 0.75, ⁇ 0.7, ⁇ 0.65, ⁇ 0.6, ⁇ 0.55, or ⁇ 0.5.
  • I 1 / I G can be ⁇ 0.4, ⁇ 0.35, ⁇ 0.3, ⁇ 0.25, ⁇ 0.22, or ⁇ 0.2.
  • the negative active material satisfies 0.22 ⁇ I 1 / I G ⁇ 0.6; e.g., 0.25 ⁇ I 1 / I G ⁇ 0.53, or 0.25 ⁇ I 1 / I G ⁇ 0.42 like.
  • the peak intensity of the SS peak and the peak intensity of the G peak meet the above relationship, which can make the coating layer have better active ion conductivity and electronic conductivity, thereby further improving the rate performance and charge-discharge cycle life of the battery, and further improve the battery The first Coulomb efficiency.
  • the negative active material in the Raman spectrum, the peak intensity ratio of the peak intensity I G peak and D peak D I G can meet the 1.05 ⁇ I D / I G ⁇ 1.50.
  • I D / I G can ⁇ 1.50, ⁇ 1.48, ⁇ 1.45, ⁇ 1.42, ⁇ 1.40, ⁇ 1.37, ⁇ 1.35, ⁇ 1.33, or ⁇ 1.30.
  • I D /I G can be ⁇ 1.28, ⁇ 1.25, ⁇ 1.23, ⁇ 1.20, ⁇ 1.18, ⁇ 1.15, ⁇ 1.12, ⁇ 1.10, ⁇ 1.08, or ⁇ 1.05.
  • 1.1 ⁇ I D /I G ⁇ 1.45; or, 1.2 ⁇ I D /I G ⁇ 1.39, etc.
  • the ratio of peak intensity I D of peak D to peak intensity I G of peak G within the above range can reduce the irreversible capacity of the material during charge and discharge cycles, while ensuring that the coating layer has excellent electrical conductivity, which is conducive to material capacity Play to improve the cycle capacity retention rate of the material, thereby improving the first coulombic efficiency, cycle performance and energy density of the secondary battery.
  • the half-value width of the D peak is 120 cm -1 to 160 cm -1 , for example, 128 cm -1 to 152 cm -1 .
  • the half-width also known as the half-height width, refers to the peak width when the peak height is half.
  • the half-value width of the D peak can be selected to be greater than or equal to 120 cm -1 , for example, greater than or equal to 128 cm -1 , which can improve the elasticity and toughness of the coating layer and make the coating layer better It adapts to the expansion and contraction of silicon-oxygen compound during charging and discharging without cracking.
  • the half-value width of the D peak can be selected to be less than or equal to 160 cm -1 , for example, less than or equal to 152 cm -1 , which can ensure that the coating layer has higher conductivity and improve the cycle performance of the secondary battery.
  • the X-ray diffraction spectrum of the negative electrode active material has a diffraction peak at a position where the diffraction angle 2 ⁇ is 19°-27° (please refer to FIG. 2), and the half peak of the diffraction peak The width may be 4°-12°, for example, 5°-10°.
  • the negative electrode active material with a diffraction peak in the position of 19° ⁇ 27° 2 ⁇ with a half-width within the above range has a higher gram capacity and a lower cycle expansion rate, which is not easy to perform during the charge and discharge cycle of the secondary battery Cracking or chalking occurs, so the cycle life of the battery can be further improved.
  • the mass percentage of sulfur in the negative active material may be 0.5% to 3%, such as 0.8% to 1.5%.
  • the content of sulfur in the negative electrode active material can be selected to be 0.5% or more, for example, 0.8% or more, which can increase the content of -SS- groups in the coating layer, improve the active ion conductivity of the coating layer, and reduce battery polarization .
  • the content of sulfur element can be selected to be 3% or less, for example 1.5% or less. On the one hand, it helps to ensure that the coating layer has higher electronic conductivity, and also has a lower thickness, which can reduce the amount of Increase the loss of material capacity reduction; on the other hand, ensure that there is no elemental sulfur residue in the material to avoid the material capacity loss caused by the completely irreversible chemical reaction between elemental sulfur and active ions. Therefore, the content of the sulfur element in the negative electrode active material is within the above range, and the cycle performance and energy density of the secondary battery can be improved.
  • the mass percentage of carbon element in the negative electrode active material can be selected from 0.1% to 4%, such as 0.5% to 3%.
  • the content of carbon in the negative electrode active material is within the above range, which is beneficial to make the coating layer have higher electronic conductivity, and can also make the coating layer have better elasticity and toughness, and better protect the silicon oxide compound. Thereby improving the cycle performance and energy density of the secondary battery.
  • a coating layer is provided on the entire outer surface of the silicon oxide. This can more fully improve the first coulombic efficiency and cycle performance of the battery.
  • the particle size distribution D v 10, D v 90 and D v 50 of the negative active material may satisfy 0.5 ⁇ (D v 90-D v 10)/D v 50 ⁇ 2.5.
  • the particle size distribution of the negative electrode active material within the above range can reduce the side reactions of the negative electrode film layer, reduce the consumption of the electrolyte, and also help prevent the particles from cracking or breaking during the charge and discharge process, and improve the structural stability of the material. Thereby further improving the cycle performance of the battery.
  • the particle size distribution D v 10, D v 90 and D v 50 of the negative electrode active material satisfies 0.8 ⁇ (D v 90-D v 10)/D v 50 ⁇ 2.0.
  • 0.8 ⁇ (D v 90-D v 10)/D v 50 ⁇ 2.0 1.02 ⁇ (D v 90-D v 10)/D v 50 ⁇ 1.48; or, 1.16 ⁇ (D v 90-D v 10)/D v 50 ⁇ 1.48, etc.
  • the average particle size D v 50 of the negative electrode active material may be 2 ⁇ m-12 ⁇ m, for example, 4 ⁇ m-8 ⁇ m, 4 ⁇ m-6.4 ⁇ m, or 5.9 ⁇ m-6.3 ⁇ m.
  • the D v 50 of the negative electrode active material can be selected to be 2 ⁇ m or more, for example, 4 ⁇ m or more, which can reduce the film-forming consumption of active ions on the negative electrode and reduce the side reactions of the electrolyte on the negative electrode, thereby reducing the irreversible capacity of the secondary battery and improving the second Cycle performance of the secondary battery.
  • the D v 50 of the negative electrode active material can be selected to be 2 ⁇ m or more, for example, 4 ⁇ m or more, which can also reduce the amount of binder added in the negative electrode, which is beneficial to increase the energy density of the secondary battery.
  • the D v 50 of the negative electrode active material can be selected to be 12 ⁇ m or less, for example, 8 ⁇ m or less, which is beneficial to improve the conductivity of active ions and electrons, and also helps prevent particles from cracking or pulverizing during charging and discharging, thereby improving secondary Cycle performance of the battery.
  • the specific surface area of the negative electrode active material optionally 0.5m 2 / g ⁇ 5m 2 / g, for example, 0.8m 2 / g ⁇ 3m 2 /g,1.07m 2 / g ⁇ 3m 2 / g, or 2.57m 2 /g ⁇ 3m 2 /g, etc.
  • the specific surface area of the negative electrode active material can be selected to be 0.5m 2 /g or more, for example, 0.8m 2 /g or more, so that the surface of the material has more active sites, which can improve the electrochemical performance of the material and meet the requirements of the secondary battery. Performance and rate performance requirements.
  • the specific surface area of the negative electrode active material can be selected to be 5m 2 /g or less, for example, 3m 2 /g or less, which is beneficial to reduce the side reaction of the electrolyte on the negative electrode, and can also reduce the film-forming consumption of active ions on the negative electrode, thereby improving the battery Cycle performance.
  • the tap density of the negative electrode active material may be 0.8 g/cm 3 to 1.3 g/cm 3 , for example, 0.9 g/cm 3 to 1.2 g/cm 3 and the like.
  • the tap density of the negative electrode active material is within the above range, which is beneficial to increase the energy density of the secondary battery.
  • the compact density of the negative electrode active material measured under a pressure of 5 tons may be 1.2 g/cm 3 ⁇ 1.5 g/cm 3 , for example, 1.25 g/cm 3 ⁇ 1.45g/cm 3 etc.
  • the pressure is relieved, and the measured compaction density is within the above range, which is beneficial to increase the energy density of the secondary battery.
  • the Raman spectrum of the negative electrode active material can be measured by using instruments and methods well known in the art.
  • a Raman spectrometer is used, such as the LabRAM HR Evolution laser microscope Raman spectrometer.
  • the peak intensity of the negative electrode active material in a certain range is the maximum value of the Raman spectrum intensity value corresponding to the Raman shift in this range.
  • the X-ray diffraction spectrum of the negative electrode active material can be measured by instruments and methods well known in the art.
  • an X-ray diffractometer is used to measure the X-ray diffraction spectrum in accordance with JIS K0131-1996 X-ray diffraction analysis general rules. If Bruker D8 Discover X-ray diffractometer is used, CuK ⁇ ray is used as the radiation source, and the ray wavelength The scanning 2 ⁇ angle range is 15° ⁇ 80°, and the scanning rate is 4°/min.
  • the content of sulfur element and carbon element in the negative electrode active material can be determined using instruments and methods known in the art.
  • the HCS-140 infrared carbon and sulfur analyzer of Shanghai Dekai Instrument Co., Ltd. is used for testing according to the measurement method of GB/T 20123-2006/ISO 15350:2000, and the detection precision meets the standard of Metrological Verification Regulation JJG395-1997.
  • the particle size distribution D v 10, D v 50 and D v 90 of the negative active material have the meanings well known in the art, and can be measured with instruments and methods well known in the art.
  • a laser particle size analyzer such as the Mastersizer 3000 laser particle size analyzer of Malvern Instruments Co., Ltd., UK.
  • D v 10, D v 50, and D v 90 are as follows:
  • D v 10 the particle size corresponding to the cumulative volume distribution percentage of the negative active material reaches 10%
  • D v 50 the particle size corresponding to when the cumulative volume distribution percentage of the negative active material reaches 50%;
  • D v 90 the particle size corresponding to when the cumulative volume distribution percentage of the negative active material reaches 90%.
  • the specific surface area of the negative electrode active material is a well-known meaning in the art, and can be measured with a well-known instrument and method in the art.
  • the tap density of the negative electrode active material is a well-known meaning in the art, and it can be measured with a well-known instrument and method in the art, for example, it can be conveniently measured with a tap density meter, such as BT-300 tap density. tester.
  • the compacted density of the negative electrode active material has a well-known meaning in the art, and can be measured with a well-known instrument and method in the art.
  • an electronic pressure testing machine such as UTM7305 electronic pressure testing machine.
  • the preparation method of the negative electrode active material includes the following steps:
  • the polymer can be selected from polyaniline (PANI for abbreviation), polyacetylene (PA for abbreviation), polyacrylonitrile (PAN for abbreviation), and polystyrene (PS for abbreviation).
  • PANI polyaniline
  • PA polyacetylene
  • PAN polyacrylonitrile
  • PS polystyrene
  • PVC polyvinyl chloride
  • PE polyethylene
  • the coating layer based on the polymer has good comprehensive properties, including good strength, elasticity and toughness, and good electrical conductivity. Therefore, the coating layer can provide effective protection to the core material and enhance the electronic conduction of the negative electrode active material Performance, which helps to improve the cycle performance of the battery.
  • the solvent is selected from N-Methylpyrrolidone (N-Methylpyrrolidone, abbreviated as NMP), Xylene (Dimethylbenzene, abbreviated as DMB), and Methylbenzene (abbreviated as Methylbenzene). It is one or more of MB) and dimethylformamide (N,N-Dimethylformamide, abbreviated as DMF).
  • the ratio of the mass of the polymer to the volume of the solvent is 0.1 g/L to 10 g/L.
  • the ratio of the mass of the polymer to the volume of the solvent is 1g/L ⁇ 5g/L, 1.5g/L ⁇ 6.5g/L, 2.5g/L ⁇ 5.5g/L, or 2.5g/L ⁇ 4g/L Wait.
  • a nuclear material with a required particle size distribution can be purchased commercially; or the nuclear material can be crushed to obtain a nuclear material with a certain particle size distribution.
  • the mass ratio of the core material to the polymer is 10 to 200, such as 20 to 100, 15 to 70, 18 to 50, or 25 to 40.
  • the higher the mass content of the polymer the higher the carbon element content in the coating layer of the negative electrode active material.
  • the mass ratio of the core material to the polymer is within the above range, while ensuring that the coating layer has a good protective effect on the core material, it can also effectively prevent the negative active material from agglomerating during the preparation process, and make the material in the charge and discharge process It has high active ion conductivity.
  • step S30 equipment and methods known in the art can be used to dry the mixed slurry, such as vacuum drying, airflow drying, spray drying, and the like.
  • step S30 can be performed by a wet coating machine.
  • the temperature at which the mixed slurry is dried in an inert atmosphere is 80°C to 300°C, for example, 110°C to 250°C, or 180°C to 230°C.
  • the heating rate can be selected from 1°C/min to 10°C/min, for example, 1°C/min to 5°C/min.
  • the inert atmosphere can be selected from one or more of nitrogen, argon and helium.
  • step S40 the sulfur powder and the polymer undergo a cross-linking reaction under an inert atmosphere to improve the elasticity and toughness of the coating layer, and at the same time improve the ion conductivity of the coating layer, thereby improving the cycle performance of the battery.
  • the mass ratio of sulfur powder to polymer is 1 to 5, for example 1.6 to 4, 2 to 4, or 2 to 3, etc.
  • the mass ratio of sulfur powder to polymer is within the above range, which is beneficial to make the coating layer of the negative active material have higher electronic conductivity and active ion conductivity at the same time, and avoid the presence of elemental sulfur residue in the coating layer, and effectively prevent This reduces the capacity loss caused by the irreversible reaction between residual elemental sulfur and active ions, thereby helping to ensure that the battery has high cycle performance.
  • the mass ratio of the sulfur powder to the polymer is within the above range, so that the sulfur powder can fully cross-link the polymer and improve the elasticity and toughness of the coating layer.
  • the temperature at which the mixed powder of solid powder and sulfur powder is heat-treated in an inert atmosphere is 200°C to 450°C, for example, 300°C to 450°C, 350°C to 450°C, or 400°C to 450°C °C etc.
  • the heat treatment temperature within the above range can ensure that the coating layer will not be completely carbonized, which is beneficial to further improve the elasticity and toughness of the coating layer, so as to better adapt to the expansion and contraction of the silicon oxide compound during the charge and discharge process; and
  • the obtained coating layer can effectively isolate the silicon-oxygen compound from the electrolyte and reduce side reactions. Therefore, it is possible to improve the cycle performance of the battery.
  • the heat treatment time is 2h-8h, for example, 2h-5h, 2h-4h, 2h-3h, or 3h-5h, etc.
  • the inert atmosphere can be selected from one or more of nitrogen, argon and helium.
  • the secondary battery includes a positive pole piece, a negative pole piece, a separator, and an electrolyte.
  • the negative pole piece includes a negative current collector and is arranged on at least one surface of the negative current collector.
  • the secondary battery of the present application adopts the negative electrode active material of the present application, it can simultaneously take into account high first-time coulombic efficiency, cycle performance, and energy density.
  • the negative electrode current collector adopts a material with good electrical conductivity and mechanical strength, such as copper foil.
  • the negative electrode active material may also optionally include a carbon material, and the carbon material is selected from the group consisting of artificial graphite, natural graphite, mesophase carbon microspheres (MCMB), hard carbon and soft carbon One or more of them.
  • the carbon material is selected from one or more of artificial graphite and natural graphite.
  • the negative electrode film layer may also optionally include one or more of a conductive agent, a binder, and a thickening agent, and there is no specific limitation on their types. Those skilled in the art can choose according to Choose according to actual needs.
  • the conductive agent may be one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the binder may be polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyvinyl alcohol (PVA), styrene butadiene rubber (SBR), sodium carboxymethyl cellulose (CMC), alginic acid One or more of sodium (SA), polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • PAA polyacrylic acid
  • PAAS sodium polyacrylate
  • PVA polyvinyl alcohol
  • SBR styrene butadiene rubber
  • CMC sodium carboxymethyl cellulose
  • SA sodium
  • PMAA polymethacrylic acid
  • CMCS carboxymethyl chitosan
  • the thickener may be sodium carboxymethyl cellulose (CMC-Na).
  • the negative pole piece can be prepared according to a conventional method in the art, such as a coating method.
  • a coating method As an example, disperse the negative electrode active material and optional conductive agent, binder, and thickener in a solvent.
  • the solvent can be deionized water to form a uniform negative electrode slurry, and the negative electrode slurry is coated on the negative electrode current collector After drying, cold pressing and other processes, the negative pole piece is obtained.
  • the positive electrode piece includes a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector and including a positive electrode active material.
  • This application does not specifically limit the types of positive active materials, and those skilled in the art can select positive active materials that can be used in secondary batteries according to actual needs.
  • the positive electrode active material can be selected from lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and olivine structure One or more of the lithium-containing phosphates.
  • the positive electrode current collector adopts a material with good electrical conductivity and mechanical strength, such as aluminum foil.
  • the positive electrode film layer may optionally include a binder and/or a conductive agent.
  • the types of the binder and the conductive agent are not specifically limited, and those skilled in the art can perform according to actual needs. select.
  • the binder may be one or more of polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE).
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • the conductive agent may be one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the above-mentioned positive pole piece can be prepared according to a conventional method in the art, such as a coating method.
  • a coating method As an example, disperse the positive electrode active material and optional conductive agent and binder in a solvent.
  • the solvent can be N-methylpyrrolidone to form a uniform positive electrode slurry.
  • the positive electrode slurry is coated on the positive electrode current collector. After drying, cold pressing and other processes, a positive pole piece is obtained.
  • the electrolyte may be a solid or gel electrolyte, or a liquid electrolyte (ie, electrolyte).
  • the electrolyte salt containing active ions may be dispersed in an organic solvent to form the electrolyte solution.
  • This application does not specifically limit the types of electrolyte salts and solvents, and those skilled in the art can make selections according to actual needs.
  • the electrolyte salt can be selected from LiPF 6 (lithium hexafluorophosphate), LiBF 4 (lithium tetrafluoroborate), LiClO 4 (lithium perchlorate), LiAsF 6 (lithium hexafluoroarsenate), LiFSI (bisfluorosulfonate) Lithium imide), LiTFSI (lithium bistrifluoromethanesulfonimide), LiTFS (lithium trifluoromethanesulfonate), LiDFOB (lithium difluorooxalate borate), LiBOB (lithium bisoxalate borate), LiPO 2 F 2 (Lithium difluorophosphate), LiDFOP (lithium difluorodioxalate phosphate) and LiTFOP (lithium tetrafluorooxalate phosphate) one or more.
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • the solvent may be selected from ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), Dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethylene propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate Ester (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB) , Ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS) and diethyl sulfone (ESE) one or several
  • the electrolyte may also optionally include additives, where there is no specific limitation on the type of additives, and can be selected according to requirements.
  • the additives can include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performance of the battery, such as additives that improve battery overcharge performance, additives that improve battery high-temperature performance, and those that improve battery low-temperature performance. Additives etc.
  • the separator is arranged between the positive pole piece and the negative pole piece to play a role of isolation.
  • isolation membrane there is no particular limitation on the type of isolation membrane, and any well-known porous structure isolation membrane with good chemical and mechanical stability can be selected, such as glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. One or more of them.
  • the isolation film can be a single-layer film or a multilayer composite film. When the isolation film is a multilayer composite film, the material of each layer can be the same or different.
  • the secondary battery can be prepared according to conventional methods in the art, for example, the positive pole piece, the separator film, and the negative pole piece are wound (or laminated) in order, so that the separator film is located between the positive pole piece and the negative pole piece to isolate Function to obtain a battery, place the battery in an outer package, inject electrolyte and seal to obtain a secondary battery.
  • Fig. 3 shows a secondary battery 5 with a square structure as an example.
  • the secondary battery may include an outer package.
  • the outer packaging is used to package the positive pole piece, the negative pole piece and the electrolyte.
  • the outer package may include a housing 51 and a cover 53.
  • the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity.
  • the housing 51 has an opening communicating with the containing cavity, and a cover plate 53 can cover the opening to close the containing cavity.
  • the positive pole piece, the negative pole piece and the separator may be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the receiving cavity.
  • the electrolyte may be an electrolyte, and the electrolyte is infiltrated in the electrode assembly 52.
  • the number of electrode assemblies 52 included in the secondary battery 5 can be one or several, which can be adjusted according to requirements.
  • the outer packaging of the secondary battery may be a hard case, such as a hard plastic case, aluminum case, steel case, or the like.
  • the outer packaging of the secondary battery may also be a soft bag, such as a pouch type soft bag.
  • the material of the soft bag can be plastic, for example, it can include one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), and the like.
  • the secondary battery can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module.
  • Fig. 5 is a battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4. Of course, it can also be arranged in any other manner. Furthermore, the plurality of secondary batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having an accommodation space, and a plurality of secondary batteries 5 are accommodated in the accommodation space.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 provided in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3.
  • the upper box body 2 can be covered on the lower box body 3 and forms a closed space for accommodating the battery module 4.
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • This application also provides a device, which includes at least one of the secondary battery, battery module, or battery pack described in this application.
  • the secondary battery, battery module or battery pack can be used as a power source of the device, and can also be used as an energy storage unit of the device.
  • the device can be, but is not limited to, mobile devices (such as mobile phones, laptop computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf Vehicles, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the device can select a secondary battery, battery module, or battery pack according to its usage requirements.
  • Fig. 8 is a device as an example.
  • the device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or a battery module can be used.
  • the device may be a mobile phone, a tablet computer, a notebook computer, etc.
  • the device usually requires lightness and thinness, and a secondary battery can be used as a power source.
  • SiO silicon oxide
  • the mixed slurry was kept and dried at 180° C. for 2 hours in an argon atmosphere to obtain a solid powder.
  • the button battery is used to test the capacity performance and cycle performance of the negative electrode active material.
  • the preparation of the button battery includes:
  • the negative active material prepared above and artificial graphite are mixed in a mass ratio of 3:7 to obtain a negative active material.
  • the negative electrode active material, conductive agent conductive carbon black Super P, binder styrene butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC) are fully mixed in an appropriate amount of deionized water at a weight ratio of 88:3:6:3 Stir and mix to form a uniform negative electrode slurry; coat the negative electrode slurry on the copper foil of the negative electrode current collector, dry and cold press to obtain an electrode pole piece, which can be used as a secondary battery Negative pole piece.
  • a lithium metal sheet is used as the counter electrode, Celgard 2400 separator is used, and electrolyte is injected to assemble a button cell.
  • the electrolyte is to mix ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC) in a volume ratio of 1:1:1 to obtain an organic solvent, and then dissolve LiPF 6 in the above organic solvent Fluorinated ethylene carbonate (FEC) is added as an additive.
  • the concentration of LiPF 6 is 1 mol/L, and the mass ratio of FEC in the electrolyte is 6%.
  • Example 1 The difference from Example 1 is that the relevant parameters in the preparation steps of the anode active material are adjusted, as shown in Table 1.
  • the LabRAM HR Evolution laser microscopic Raman spectrometer was used to measure the negative electrode active materials in each example and comparative example. Among them, a solid-state laser with a wavelength of 523nm was used as the light source, the beam diameter was 1.2 ⁇ m, and the power was 1mW; the measurement mode was macro Raman; CCD detector is used.
  • the negative electrode active material powder is pressed into a tablet, 3 points are randomly selected on the tablet for testing, and three sets of measured values are obtained and averaged.
  • the button cell was subjected to 50 cycles of charge-discharge test according to the above method, and the delithiation capacity was recorded each time.
  • the first coulombic efficiency of the negative electrode active material (%) the first delithiation capacity/the first lithium insertion capacity ⁇ 100%
  • Retention rate of cycle capacity of negative electrode active material (%) 50th delithiation capacity/first delithiation capacity ⁇ 100%
  • I 1 is the negative electrode active material in the Raman spectrum intensity of the scattered peak shift is 900cm -1 ⁇ 960cm -1 peak position of the Raman;
  • I D is a negative electrode active material is displaced Raman spectrum peak intensity of the scattered peak 1300cm -1 ⁇ 1380cm -1 in the Raman position;
  • I G is the peak intensity of the scattering peak at the Raman shift of 1520 cm -1 ⁇ 1590 cm -1 in the Raman spectrum of the negative active material
  • the particle size distribution refers to (D v 90-D v 10)/D v 50.
  • the anode active material of the present application includes a core material and at least a part of the polymer modified coating layer on the surface, and in the Raman spectrum of the anode active material of the present application, the Raman shift is 900 cm -1 ⁇ 960cm - 1, 1300cm ⁇ 1520cm -1 1380cm -1 and positions -1 ⁇ 1590cm -1, respectively, with scattering peaks, and the displacement of the peak intensity of a Raman scattering peak of 900cm -1 ⁇ 960cm -1 position I 1 and the peak intensity I G of the scattering peak at the Raman shift of 1520 cm -1 ⁇ 1590 cm -1 satisfies 0.2 ⁇ I 1 / I G ⁇ 0.8, so that the negative electrode active material of the present application has a higher first coulombic efficiency And cycle life.
  • Using the negative electrode active material of the present application can improve the energy density, first coulombic efficiency and cycle performance of the secondary battery.

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Abstract

本申请公开了一种负极活性材料、其制备方法、及其相关的二次电池、电池模块、电池包和装置。所述负极活性材料包括核材料及其至少一部分表面上的聚合物改性包覆层；所述核材料包括硅基材料、锡基材料中的一种或几种；所述包覆层包含硫元素和碳元素；所述负极活性材料的拉曼光谱中，在拉曼位移为900cm -1～960cm -1、1300cm -1～1380cm -1及1520cm -11590cm -1的位置分别具有散射峰，且在拉曼位移为900cm -1～960cm - 1位置的散射峰的峰强度I 1与在拉曼位移为1520cm -1～1590cm -1位置的散射峰的峰强度I G之间满足0.2≤I 1/I G≤0.8。

Description

负极活性材料、其制备方法、及其相关的二次电池、电池模块、电池包和装置
相关申请的交叉引用
本申请要求享有于2019年07月29日提交的名称为“负极活性材料及二次电池”的中国专利申请201910687174.2的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本申请属于储能装置技术领域，具体涉及一种负极活性材料、其制备方法、及其相关的二次电池、电池模块、电池包和装置。
背景技术
随着环境保护问题日益受到重视，环境友好的二次电池逐渐被应用到电动汽车中。不同于消费类电子产品用二次电池，动力型二次电池对能量密度和循环寿命都有着更高的要求。与传统的碳材料相比，硅基材料和锡基材料作为负极活性材料具有很高的理论克容量，为石墨类负极活性材料的数倍，因此，业界可期望采用硅基材料来提升二次电池的能量密度。
然而，硅基材料和锡基材料的循环寿命较差，在实际应用中造成二次电池的循环性能变差。基于此，需要提供一种在具有较高克容量的前提下，还具有较长循环寿命的负极活性材料。
发明内容
本申请第一方面提供一种负极活性材料，其包括核材料及其至少一部分表面上的聚合物改性包覆层；所述核材料包括硅基材料、锡基材料中的一种或几种；所述包覆层包含硫元素和碳元素；所述负极活性材料的拉曼光谱中，在拉曼位移为900cm -1～960cm -1、1300cm -1～1380cm -1及1520cm -1～1590cm -1的位置分别具有散射峰，且在拉曼位移为900cm -1～960cm -1位置的散射峰的峰强度I 1与在拉曼位移为1520cm -1～1590cm -1位置的散射峰的峰强度I G之间满足0.2≤I 1/I G≤0.8。
令人惊奇地发现，本申请提供的负极活性材料包括核材料及其至少一部分表面上的 聚合物改性包覆层；所述核材料包括硅基材料、锡基材料中的一种或几种；所述包覆层包含硫元素和碳元素，且其在拉曼位移为900cm -1～960cm -1、1300cm -1～1380cm -1及1520cm -1～1590cm -1的位置分别具有散射峰，同时在拉曼位移为900cm -1～960cm -1位置的散射峰的峰强度与在拉曼位移为1520cm -1～1590cm -1位置的散射峰的峰强度之间满足预设关系，使得负极活性材料具有较高的离子传导性和电子传导性，由此负极活性材料的首次库伦效率及循环寿命均得到显著的改善，从而使得二次电池的首次库伦效率及循环性能均得到较大提升。
在上述任意实施方式中，所述I 1与I G之间可满足0.22≤I 1/I G≤0.6。负极活性材料的I 1与I G之间满足上述关系，能进一步提高电池的倍率性能和循环寿命，并且进一步提高电池的首次库伦效率。
在上述任意实施方式中，所述负极活性材料的拉曼光谱中拉曼位移为1300cm -1～1380cm -1位置的散射峰的峰强度为I D，所述I D与I G之间可满足1.05≤I D/I G≤1.50；可选的，1.1≤I D/I G≤1.45。负极活性材料的I D与I G之间满足上述关系，能进一步提高二次电池的循环性能，并且还有利于提高二次电池的首次库伦效率和能量密度。
在上述任意实施方式中，所述负极活性材料的拉曼光谱中拉曼位移为1300cm -1～1380cm -1位置的散射峰的半峰宽为120cm -1～160cm -1，可选为128cm -1～152cm -1。所述负极活性材料的拉曼光谱中，拉曼位移为1300cm -1～1380cm -1位置的散射峰的半峰宽在所述范围内，能进一步提高二次电池的循环性能。
在上述任意实施方式中，所述负极活性材料中硫元素的质量百分含量可选为0.5％～3％，例如为0.8％～1.5％。负极活性材料中硫元素的含量在上述范围内，能提高二次电池的循环性能和能量密度。
在上述任意实施方式中，所述负极活性材料中碳元素的质量百分含量可选为0.1％～4％，例如为0.5％～3％。负极活性材料中碳元素的含量在上述范围内，能提高二次电池的循环性能和能量密度。
在上述任意实施方式中，所述负极活性材料的X射线衍射光谱中，在衍射角2θ为19°～27°的位置具有衍射峰且半峰宽为4°～12°；可选的，所述半峰宽为5°～10°。在X射线衍射角2θ为19°～27°的位置内具有衍射峰且半峰宽在上述范围内的负极活性材料，能进一步改善电池的循环寿命。
在上述任意实施方式中，所述负极活性材料的粒度分布满足：0.5≤(D v90-D v10)/D v50≤2.5；可选的，0.8≤(D v90-D v10)/D v50≤2.0。负极活性材料的粒度分布在上述范围内，能进一步提高电池的循环性能。
在上述任意实施方式中，所述负极活性材料的平均粒径D v50为2μm～12μm，可选为4μm～8μm。负极活性材料的D v50在上述范围内，能进一步提高二次电池的循环性能，并且还有利于提高二次电池的能量密度。
在上述任意实施方式中，所述负极活性材料的比表面积为0.5m 2/g～5m 2/g，可选为0.8m 2/g～3m 2/g。负极活性材料的比表面积在适当范围内，能在满足二次电池的动力学性能和倍率性能需求的同时，进一步提升二次电池的循环性能。
在上述任意实施方式中，所述负极活性材料的振实密度为0.8g/cm 3～1.3g/cm 3，可选为0.9g/cm 3～1.2g/cm 3。负极活性材料的振实密度在上述范围内，有利于提高二次电池的能量密度。
在上述任意实施方式中，所述负极活性材料在5吨(相当于49KN)压力下测得的压实密度为1.2g/cm 3～1.5g/cm 3，可选为1.25g/cm 3～1.45g/cm 3。负极活性材料在49KN压力下测得的压实密度在上述范围内，有利于提高二次电池的能量密度。
在上述任意实施方式中，所述硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮化合物、硅合金中的一种或几种；可选的，所述硅基材料选自硅氧化合物；所述锡基材料可选自单质锡、锡氧化合物、锡合金中的一种或几种。这些材料具有较高的克容量，能使采用其的二次电池获得较高的能量密度。
本申请第二方面提供一种负极活性材料的制备方法，其包括以下步骤：
提供包含聚合物的溶液；
将核材料与所述溶液混合，得到混合浆料，其中所述核材料包括硅基材料、锡基材料中的一种或几种；
将所述混合浆料在惰性气氛下进行干燥，得到固体粉末；
将所述固体粉末与硫粉混合，并在惰性气氛中进行热处理，得到负极活性材料；
其中，所述负极活性材料包括核材料及其至少一部分表面上的聚合物改性包覆层，所述包覆层包含硫元素和碳元素，并且所述负极活性材料的拉曼光谱中，在拉曼位移为900cm -1～960cm -1、1300cm -1～1380cm -1及1520cm -1～1590cm -1的位置分别具有散射峰，且在拉曼位移为900cm -1～960cm -1位置的散射峰的峰强度I 1与在拉曼位移为1520cm -1～1590cm -1位置的散射峰的峰强度I G之间满足0.2≤I 1/I G≤0.8。
本申请提供的制备方法得到的负极活性材料包括核材料及其至少一部分表面上的聚合物改性包覆层；所述核材料包括硅基材料、锡基材料中的一种或几种；所述包覆层包含硫元素和碳元素，且其在拉曼位移为900cm -1～960cm -1、1300cm -1～1380cm -1及1520cm - 1～1590cm -1的位置分别具有散射峰，同时在拉曼位移为900cm -1～960cm -1位置的散射峰 的峰强度与在拉曼位移为1520cm -1～1590cm -1位置的散射峰的峰强度之间满足预设关系，使得负极活性材料具有较高的离子传导性和电子传导性，由此负极活性材料的首次库伦效率及循环寿命均得到显著的改善，从而使得二次电池的首次库伦效率及循环性能均得到较大提升。
在上述任意实施方式中，所述聚合物包括聚苯胺、聚乙炔、聚丙烯腈、聚苯乙烯、聚氯乙烯和聚乙烯中的一种或几种。基于该聚合物的包覆层能对核材料提供有效保护，并提升负极活性材料的电子传导性能，从而有利于提高二次电池的循环性能。
在上述任意实施方式中，所述包含聚合物的溶液中，所述聚合物的质量与所述溶剂的体积之比为0.1g/L～10g/L；可选的，所述聚合物的质量与所述溶剂的体积之比为1g/L～5g/L。聚合物的加入量适当，有利于改善负极活性材料的粒径分布，其中可使负极活性材料的D v10、D v50和D v99在适当范围内，由此可以改善二次电池的能量密度和循环性能。
在上述任意实施方式中，所述混合浆料中核材料与聚合物的质量比为10～200；可选的，所述混合浆料中核材料与聚合物的质量比为20～100。核材料和聚合物的质量比在适当范围内，有利于使二次电池具有较高的能量密度和循环性能。
在上述任意实施方式中，所述固体粉末与硫粉混合的步骤满足：所述硫粉的质量与所述固体粉末中聚合物的质量之比为1～5；可选的，所述硫粉的质量与所述固体粉末中聚合物的质量之比为2～4。硫粉与聚合物的质量比在上述范围内，有利于使二次电池获得较高的循环性能。
在上述任意实施方式中，所述热处理的温度为200℃～450℃；可选的，所述热处理的温度为300℃～450℃。热处理温度在上述范围内，能提高二次电池的循环性能。
在上述任意实施方式中，所述热处理的时间为2h～8h；可选的，所述热处理的时间为3h～5h。
本申请第三方面提供一种二次电池，其包括根据第一方面的负极活性材料或根据本申请第二方面的制备方法得到的负极活性材料。
本申请的二次电池由于采用本申请的负极活性材料，因而能同时兼顾较高的能量密度、首次库伦效率和循环性能。
本申请第四方面提供一种电池模块，其包括根据本申请第三方面的二次电池。
本申请第五方面提供一种电池包，其包括根据本申请第四方面的电池模块。
本申请第六方面提供一种装置，其包括根据本申请第三方面的二次电池、根据本申请第四方面的电池模块、或根据本申请第五方面的电池包中的至少一种。
本申请的电池模块、电池包和装置包括本申请所述二次电池，因而至少具有与所述二次电池相同或类似的技术效果。
附图说明
图1为根据本申请的一种负极活性材料的拉曼光谱图。
图2为根据本申请的一种负极活性材料的X射线衍射光谱(XRD)图。
图3是二次电池的一实施方式的示意图。
图4是图3的分解图。
图5是电池模块的一实施方式的示意图。
图6是电池包的一实施方式的示意图。
图7是图6的分解图。
图8是二次电池用作电源的装置的一实施方式的示意图。
具体实施方式
为了使本申请的发明目的、技术方案和有益技术效果更加清晰，以下结合具体实施例对本申请进行详细说明。应当理解的是，本说明书中描述的实施例仅仅是为了解释本申请，并非为了限定本申请。
为了简便，本文仅明确地公开了一些数值范围。然而，任意下限可以与任何上限组合形成未明确记载的范围；以及任意下限可以与其它下限组合形成未明确记载的范围，同样任意上限可以与任意其它上限组合形成未明确记载的范围。此外，尽管未明确记载，但是范围端点间的每个点或单个数值都包含在该范围内。因而，每个点或单个数值可以作为自身的下限或上限与任意其它点或单个数值组合或与其它下限或上限组合形成未明确记载的范围。
在本文的描述中，需要说明的是，除非另有说明，“以上”、“以下”为包含本数，“一种或几种”中“几种”的含义是两种及两种以上。
本申请的上述发明内容并不意欲描述本申请中的每个公开的实施方式或每种实现方式。如下描述更具体地举例说明示例性实施方式。在整篇申请中的多处，通过一系列实施例提供了指导，这些实施例可以以各种组合形式使用。在各个实施例中，列举仅作为代表性组，不应解释为穷举。
负极活性材料
本申请一方面提供一种负极活性材料，所述负极活性材料包括核材料及其至少一部分表面上的聚合物改性包覆层；所述核材料包括硅基材料、锡基材料中的一种或几种；所述包覆层包含硫元素和碳元素；以及所述负极活性材料的拉曼光谱中，在拉曼位移为900cm -1～960cm -1、1300cm -1～1380cm -1及1520cm -1～1590cm -1的位置分别具有散射峰(请参照图1)，并且所述负极活性材料在拉曼位移为900cm -1～960cm -1位置的散射峰的峰强度I 1与在拉曼位移为1520cm -1～1590cm -1位置的散射峰的峰强度I G之间满足0.2≤I 1/I G≤0.8。
本申请的负极活性材料，在核材料的至少一部分外表面包覆有聚合物改性包覆层，对核材料起到良好的保护作用，抑制电解液在核材料表面的副反应，保证负极活性材料具有较高的容量及循环寿命。
并且，所述负极活性材料的拉曼光谱中，在拉曼位移为900cm -1～960cm -1的位置具有归属于S-S键的散射峰(下文简称为S-S峰)，使得包覆层具有较高的活性离子传导性能；在拉曼位移为1300cm -1～1380cm -1的位置具有碳的D频带的散射峰(下文简称为D峰)，在拉曼位移为1520cm -1～1590cm -1的位置具有碳的G频带的散射峰(下文简称为G峰)，使得包覆层具有较高的电子传导性能。电池充电过程中，S-S键发生断裂并与活性离子结合，进行离子的迁移，且具有较高的迁移效率；而电池放电过程中活性离子脱出，S-S键重新键和。在电池充放电过程中，仅发生S-S键的断裂和键和，碳基骨架的结构保持不变和完整，保证了包覆层对硅氧化合物的保护作用。
特别地，负极活性材料的拉曼光谱中，S-S峰的峰强度I 1与G峰的峰强度I G之间满足0.2≤I 1/I G≤0.8。经发明人研究发现，S-S峰的峰强度与G峰的峰强度满足上述预设关系，负极活性材料的导离子性能及导电子性能均得到大幅度提高。由此，负极活性材料具有较高的活性离子和电子的传导性能，有利于负极活性材料的容量发挥及在循环过程中的容量保持率，并且还可以减小电池极化，降低电池的不可逆容量，从而显著提高二次电池的首次库伦效率及循环性能。
因此，采用本申请的负极活性材料，使得二次电池能够同时兼顾较高的首次库伦效率、循环性能和能量密度。
本申请的负极活性材料，核材料包括硅基材料、锡基材料中的一种或几种。
可选的，所述硅基材料选自单质硅、硅氧化合物、硅碳复合物、硅氮化合物、硅合金中的一种或几种。例如，所述硅基材料选自硅氧化合物。其中硅氧化合物的理论克容量约为石墨的7倍，且与硅单质相比其充电过程中的体积膨胀大大减小，电池的循环稳定性能得到较大的提升。
可选的，所述锡基材料可选自单质锡、锡氧化合物、锡合金中的一种或几种。
本申请的负极活性材料，S-S峰的峰强度I 1与G峰的峰强度I G之比I 1/I G可以≤0.8、≤0.75、≤0.7、≤0.65、≤0.6、≤0.55、或≤0.5。I 1/I G可以≥0.4、≥0.35、≥0.3、≥0.25、≥0.22、或≥0.2。
可选的，所述负极活性材料满足0.22≤I 1/I G≤0.6；例如，0.25≤I 1/I G≤0.53，或0.25≤I 1/I G≤0.42等。S-S峰的峰强度与G峰的峰强度满足上述关系，可使包覆层具有更优的活性离子传导性能和电子传导性能，从而进一步提高电池的倍率性能和充放电循环寿命，并进一步提高电池的首次库伦效率。
在一些实施方式中，所述负极活性材料的拉曼光谱中，D峰的峰强度I D与G峰的峰强度I G之比可满足1.05≤I D/I G≤1.50。
可选的，本申请的负极活性材料，I D/I G可以≤1.50、≤1.48、≤1.45、≤1.42、≤1.40、≤1.37、≤1.35、≤1.33、或≤1.30。I D/I G可以≥1.28、≥1.25、≥1.23、≥1.20、≥1.18、≥1.15、≥1.12、≥1.10、≥1.08、或≥1.05。可选的，1.1≤I D/I G≤1.45；或者，1.2≤I D/I G≤1.39等。
D峰的峰强度I D与G峰的峰强度I G之比在上述范围内，能降低材料在充放电循环中的不可逆容量，同时保证包覆层具有优良的导电性能，有利于材料容量的发挥，提高材料的循环容量保持率，从而提高二次电池的首次库伦效率、循环性能和能量密度。
在一些实施方式中，本申请的负极活性材料，可选的，所述D峰的半峰宽为120cm -1～160cm -1，例如为128cm -1～152cm -1。
在本文中，半峰宽，又称半高宽，指的是峰值高度一半时的峰宽度。
所述负极活性材料的拉曼光谱中，D峰的半峰宽可选为大于等于120cm -1，例如为大于等于128cm -1，能改善包覆层的弹性和韧性，使包覆层更好地适应硅氧化合物在充放电过程中的膨胀和收缩，而不发生破裂。D峰的半峰宽可选为小于等于160cm -1，例如为小于等于152cm -1，能保证包覆层具有较高的导电性能，提高二次电池的循环性能。
在一些实施方式中，可选的，所述负极活性材料的X射线衍射光谱中，在衍射角2θ为19°～27°的位置具有衍射峰(请参照图2)，该衍射峰的半峰宽可选为4°～12°，例如为5°～10°。在2θ为19°～27°的位置内具有衍射峰且半峰宽在上述范围内的负极活性材料具有较高的克容量和较低的循环膨胀率，在二次电池充放电循环过程中不易发生破裂或粉化，因此可进一步改善电池的循环寿命。
在一些实施方式中，所述负极活性材料中硫元素的质量百分含量可选为0.5％～3％，例如为0.8％～1.5％等。
负极活性材料中硫元素的含量可选为0.5％以上，例如为0.8％以上，能增加包覆层中-S-S-基团的含量，提高包覆层的活性离子传导性能，减小电池极化。硫元素的含量可选为3％以下，例如为1.5％以下，一方面有利于保证包覆层具有较高的电子传导性能的同时，还具有较低的厚度，可以减少因为包覆层含量的增加导致的材料容量降低的损失；另一方面确保材料中不存在单质硫残留，以避免单质硫与活性离子发生完全不可逆的化学反应导致的材料容量损失。因此，负极活性材料中硫元素的含量在上述范围内，能提高二次电池的循环性能及能量密度。
在一些实施方式中，所述负极活性材料中碳元素的质量百分含量可选为0.1％～4％，例如为0.5％～3％等。负极活性材料中碳元素的含量在上述范围内，有利于使包覆层具有较高的电子传导性能，并且还能使包覆层具有较优的弹性和韧性，更好地保护硅氧化合物，从而提高二次电池的循环性能及能量密度。
在一些实施方式中，可选的，在硅氧化物的全部外表面均具有包覆层。这样能更加充分地改善电池的首次库伦效率及循环性能。
在一些实施方式中，所述负极活性材料的粒度分布D v10、D v90及D v50之间可满足0.5≤(D v90-D v10)/D v50≤2.5。负极活性材料的粒度分布在上述范围内，能减少负极膜层的副反应，降低对电解液的消耗，并且还有利于防止颗粒在充放电过程中发生破裂或破碎，提高材料的结构稳定性，从而进一步提高电池的循环性能。
可选的，负极活性材料的粒度分布D v10、D v90及D v50之间满足0.8≤(D v90-D v10)/D v50≤2.0。例如，1.02≤(D v90-D v10)/D v50≤1.48；或者，1.16≤(D v90-D v10)/D v50≤1.48等。
在一些实施方式中，所述负极活性材料的平均粒径D v50可选为2μm～12μm，例如为4μm～8μm，4μm～6.4μm，或5.9μm～6.3μm等。
负极活性材料的D v50可选为2μm以上，例如为4μm以上，能减少活性离子在负极的成膜消耗，以及减少电解液在负极的副反应，从而降低二次电池的不可逆容量，提高二次电池的循环性能。负极活性材料的D v50可选为2μm以上，例如为4μm以上，还能减少负极中粘结剂的添加量，这有利于提高二次电池的能量密度。
负极活性材料的D v50可选为12μm以下，例如为8μm以下，有利于提高活性离子和电子的传导性能，并且还有利于防止颗粒在充放电过程中发生破裂或粉化，从而提高二次电池的循环性能。
在一些实施方式中，所述负极活性材料的比表面积可选为0.5m 2/g～5m 2/g，例如为0.8m 2/g～3m 2/g，1.07m 2/g～3m 2/g，或2.57m 2/g～3m 2/g等。
负极活性材料的比表面积可选为0.5m 2/g以上，例如为0.8m 2/g以上，使得材料表面具有较多的活性位，能提高材料的电化学性能，满足二次电池对动力学性能及倍率性能的要求。负极活性材料的比表面积可选为5m 2/g以下，例如为3m 2/g以下，有利于减少电解液在负极的副反应，并且还能减少活性离子在负极的成膜消耗，从而提高电池的循环性能。
在一些实施方式中，所述负极活性材料的振实密度可选为0.8g/cm 3～1.3g/cm 3，例如为0.9g/cm 3～1.2g/cm 3等。负极活性材料的振实密度在上述范围内，有利于提高二次电池的能量密度。
在一些实施方式中，所述负极活性材料在5吨(相当于49KN)压力下测得的压实密度可选为1.2g/cm 3～1.5g/cm 3，例如为1.25g/cm 3～1.45g/cm 3等。负极活性材料在压到5吨(相当于49KN)压力保压30s后卸压，测得的压实密度在上述范围内，有利于提高二次电池的能量密度。
在本申请中，可以用本领域公知的仪器及方法进行测定负极活性材料的拉曼光谱。例如采用拉曼光谱仪，如LabRAM HR Evolution型激光显微拉曼光谱仪。所述负极活性材料在某一范围内的峰强度即为拉曼位移在该范围内对应的拉曼图谱强度值的最大值。
在本申请中，可以用本领域公知的仪器及方法进行测定负极活性材料的X射线衍射光谱。例如采用X射线衍射仪，依据JIS K0131-1996 X射线衍射分析通则测定X射线衍射光谱。如采用Bruker D8 Discover型X射线衍射仪，以CuK α射线为辐射源，射线波长
Figure PCTCN2020102062-appb-000001
扫描2θ角范围为15°～80°，扫描速率为4°/min。
在本申请中，可以用本领域公知的仪器及方法进行测定负极活性材料中的硫元素及碳元素的含量。例如采用上海德凯仪器有限公司的HCS-140型红外碳硫分析仪，依据GB/T 20123-2006/ISO 15350:2000的测定方法进行测试，检测精密度符合计量检定规程JJG395-1997标准。
在本申请中，负极活性材料的粒度分布D v10、D v50及D v90为本领域公知的含义，可以用本领域公知的仪器及方法进行测定。例如用激光粒度分析仪进行测定，如英国马尔文仪器有限公司的Mastersizer3000型激光粒度分析仪。
其中，D v10、D v50、D v90的物理定义如下：
D v10：所述负极活性材料累计体积分布百分数达到10％时所对应的粒径；
D v50：所述负极活性材料累计体积分布百分数达到50％时所对应的粒径；
D v90：所述负极活性材料累计体积分布百分数达到90％时所对应的粒径。
在本申请中，负极活性材料的比表面积为本领域公知的含义，可以用本领域公知的 仪器及方法进行测定。例如可以参照GB/T 19587-2004气体吸附BET法测定固态物质比表面积标准，采用氮气吸附比表面积分析测试方法测试，并用BET(Brunauer Emmett Teller)法计算得出，其中氮气吸附比表面积分析测试可以通过美国Micromeritics公司的Tri StarⅡ3020型比表面与孔隙分析仪进行。
在本申请中，负极活性材料的振实密度为本领域公知的含义，可以用本领域公知的仪器及方法进行测定，例如用振实密度测定仪方便地测定，如BT-300型振实密度测定仪。
在本申请中，负极活性材料的压实密度为本领域公知的含义，可以用本领域公知的仪器及方法进行测定。例如可以参照GB/T24533-2009标准，通过电子压力试验机进行，如UTM7305型电子压力试验机。称取1g负极活性材料，加入底面积为1.327cm 2的模具中，加压至5吨(相当于49KN)，保压30s，然后卸压，保持10s，然后记录并计算得到负极活性材料的压实密度。
接下来提供一种负极活性材料的制备方法，通过该制备方法能够制备得到本申请的负极活性材料。
作为具体的示例，负极活性材料的制备方法包括以下步骤：
S10，提供包含聚合物的溶液。
S20，将核材料与溶液混合得到混合浆料。
S30，将混合浆料在惰性气氛下进行干燥，得到固体粉末。
S40，将固体粉末与硫粉混合，并在惰性气氛中进行热处理，得到负极活性材料。
在步骤S10，聚合物可以选自聚苯胺(Polyaniline，简写为PANI)、聚乙炔(Polyacetylene，简写为PA)、聚丙烯腈(Polyacrylonitrile，简写为PAN)、聚苯乙烯(Polystyrene，简写为PS)、聚氯乙烯(Polyvinyl chloride，简写为PVC)及聚乙烯(Polyethylene，简写为PE)中的一种或几种。基于该聚合物的包覆层具有良好的综合性能，包括良好的强度、弹性和韧性，以及良好的导电性能等，因此包覆层能对核材料提供有效保护，并提升负极活性材料的电子传导性能，从而有利于提高电池的循环性能。
在步骤S10对溶剂的种类没有特别的限制，可选的，溶剂选自N-甲基吡咯烷酮(N-Methyl pyrrolidone，简写为NMP)、二甲苯(Dimethylbenzene，简写为DMB)、甲苯(Methylbenzene，简写为MB)及二甲基甲酰胺(N,N-Dimethylformamide，简写为DMF)中的一种或几种。
在步骤S10，可选的，聚合物的质量与溶剂的体积之比为0.1g/L～10g/L。例如，聚合物的质量与溶剂的体积之比为1g/L～5g/L，1.5g/L～6.5g/L，2.5g/L～5.5g/L，或2.5g/L～ 4g/L等。
在步骤S20，可以通过市售购买所需粒径分布的核材料；或者将核材料进行粉碎处理，得到具有一定粒径分布的核材料。
在步骤S20，可选的，核材料与聚合物的质量比为10～200，例如20～100，15～70，18～50，或25～40等。聚合物的质量含量越高，负极活性材料的包覆层中的碳元素含量越高。核材料与聚合物的质量比在上述范围内，在保证包覆层对核材料具有良好的保护作用的同时，还能有效防止负极活性材料在制备过程中发生团聚，并使得材料在充放电过程中具有较高的活性离子传导性能。
在步骤S30，可以采用本领域已知的设备和方法对混合浆料进行干燥，如真空干燥、气流干燥、喷雾干燥等。作为示例，步骤S30可以采用湿法包覆机进行。
可选的，在惰性气氛对混合浆料进行干燥的温度为80℃～300℃，例如110℃～250℃，或180℃～230℃等。升温速率可选为1℃/min～10℃/min，例如1℃/min～5℃/min。
在步骤S30，惰性气氛可选自氮气、氩气及氦气中的一种或几种。
在步骤S40，硫粉与聚合物在惰性气氛下发生交联反应，提高包覆层的弹性及韧性，同时提高包覆层的导离子性，从而提升电池的循环性能。
可选的，硫粉与聚合物的质量比为1～5，例如1.6～4，2～4，或2～3等。硫粉与聚合物的质量比在上述范围内，有利于使负极活性材料的包覆层同时具有较高的电子传导性能及活性离子传导性能，并且避免包覆层中存在单质硫残留，有效防止了残余单质硫与活性离子发生不可逆反应造成的容量损失，从而有利于保证电池具有较高的循环性能。
此外，硫粉与聚合物的质量比在上述范围内，还使得硫粉对聚合物进行充分交联，提高包覆层的弹性和韧性。
在步骤S40，可选的，在惰性气氛对固体粉末与硫粉的混合粉体进行热处理的温度为200℃～450℃，例如300℃～450℃，350℃～450℃，或400℃～450℃等。热处理温度在上述范围内，可以确保所述包覆层不会完全碳化，有利于进一步提高包覆层的弹性和韧性，以更好地适应硅氧化合物在充放电过程中的膨胀和收缩；并且得到的包覆层能将硅氧化合物与电解液有效隔绝，减少副反应。因此，实现提高电池的循环性能。
可选的，热处理的时间为2h～8h，例如为2h～5h，2h～4h，2h～3h，或3h～5h等。
在步骤S40，惰性气氛可选自氮气、氩气及氦气中的一种或几种。
二次电池
本申请的另一方面提供一种二次电池，所述二次电池包括正极极片、负极极片、隔离膜及电解质，所述负极极片包括负极集流体以及设置在负极集流体至少一个表面上且包括负极活性物质的负极膜层，所述负极活性物质包括本申请的负极活性材料。
本申请的二次电池由于采用了本申请的负极活性材料，因而能同时兼顾较高的首次库伦效率、循环性能及能量密度。
本申请的二次电池，所述负极集流体采用具有良好导电性及机械强度的材质，例如铜箔。
本申请的二次电池，进一步地，所述负极活性物质还可选地包括碳材料，所述碳材料选自人造石墨、天然石墨、中间相微碳球(MCMB)、硬碳及软碳中的一种或几种。可选的，所述碳材料选自人造石墨及天然石墨中的一种或几种。
本申请的二次电池，所述负极膜层还可选地包括导电剂、粘结剂及增稠剂中的一种或几种，对它们的种类不做具体限制，本领域技术人员可以根据实际需求进行选择。
可选的，所述导电剂可以是石墨、超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的一种或几种。
可选的，所述粘结剂可以是聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚乙烯醇(PVA)、丁苯橡胶(SBR)、羧甲基纤维素钠(CMC)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的一种或几种。
可选的，所述增稠剂可以是羧甲基纤维素钠(CMC-Na)。
可以按照本领域常规方法制备负极极片，例如涂布法。作为示例，将负极活性物质及可选的导电剂、粘结剂和增稠剂分散于溶剂中，溶剂可以是去离子水，形成均匀的负极浆料，将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，得到负极极片。
本申请的二次电池，所述正极极片包括正极集流体以及设置在正极集流体至少一个表面上且包括正极活性物质的正极膜层。本申请对正极活性物质的种类不做具体限制，本领域技术人员可以根据实际需求进行选择能够用于二次电池的正极活性物质。
可选的，所述正极活性物质可选自锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍锰氧化物、锂镍钴锰氧化物、锂镍钴铝氧化物、橄榄石结构的含锂磷酸盐中的一种或几种。
本申请的二次电池，正极集流体采用具有良好导电性及机械强度的材质，例如铝箔。
本申请的二次电池，所述正极膜层中还可选的包括粘结剂和/或导电剂，对粘结剂、 导电剂的种类不做具体限制，本领域技术人员可以根据实际需求进行选择。
可选的，所述粘结剂可以是聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)中的一种或几种。
可选的，导电剂可以是石墨、超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的一种或几种。
可以按照本领域常规方法制备上述正极极片，例如涂布法。作为示例，将正极活性物质及可选的导电剂和粘结剂分散于溶剂中，溶剂可以是N-甲基吡咯烷酮，形成均匀的正极浆料，将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，得到正极极片。
本申请的二次电池，所述电解质可以采用固态或凝胶电解质，也可以采用液态电解质(即电解液)。可以将含有活性离子的电解质盐分散于有机溶剂中形成所述电解液。本申请对电解质盐和溶剂的种类不做具体限制，本领域技术人员可以根据实际需求进行选择。
可选的，所述电解质盐可以选自LiPF 6(六氟磷酸锂)、LiBF 4(四氟硼酸锂)、LiClO 4(高氯酸锂)、LiAsF 6(六氟砷酸锂)、LiFSI(双氟磺酰亚胺锂)、LiTFSI(双三氟甲磺酰亚胺锂)、LiTFS(三氟甲磺酸锂)、LiDFOB(二氟草酸硼酸锂)、LiBOB(二草酸硼酸锂)、LiPO 2F 2(二氟磷酸锂)、LiDFOP(二氟二草酸磷酸锂)及LiTFOP(四氟草酸磷酸锂)中的一种或几种。
可选的，所述溶剂可以选自碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸亚丁酯(BC)、氟代碳酸亚乙酯(FEC)、甲酸甲酯(MF)、乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(PA)、丙酸甲酯(MP)、丙酸乙酯(EP)、丙酸丙酯(PP)、丁酸甲酯(MB)、丁酸乙酯(EB)、1,4-丁内酯(GBL)、环丁砜(SF)、二甲砜(MSM)、甲乙砜(EMS)及二乙砜(ESE)中的一种或几种。
本申请的二次电池，所述电解液中还可选地包括添加剂，其中对添加剂的种类没有具体的限制，可根据需求进行选择。例如添加剂可以包括负极成膜添加剂，也可以包括正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温性能的添加剂、改善电池低温性能的添加剂等。
本申请的二次电池，所述隔离膜设置在正极极片和负极极片之间起到隔离的作用。对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜，例如玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的一种或几种。隔离膜可以是单层薄膜，也可以是多层复合薄膜。隔离膜为多层复合薄膜 时，各层的材料可以相同，也可以不同。
可以按照本领域常规方法制备二次电池，例如将正极极片、隔离膜、负极极片按顺序卷绕(或叠片)，使隔离膜处于正极极片与负极极片之间起到隔离的作用，得到电芯，将电芯置于外包装中，注入电解液并封口，得到二次电池。
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。如图3是作为一个示例的方形结构的二次电池5。
在一些实施例中，二次电池可包括外包装。该外包装用于封装正极极片、负极极片和电解质。
在一些实施例中，参照图4，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。
正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔。电解质可采用电解液，电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或几个，可根据需求来调节。
在一些实施例中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，如可包括聚丙烯(PP)、聚对苯二甲酸丁二醇酯(PBT)、聚丁二酸丁二醇酯(PBS)等中的一种或几种。
在一些实施例中，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为多个，具体数量可根据电池模块的应用和容量来调节。
图5是作为一个示例的电池模块4。参照图5，在电池模块4中，多个二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间。
在一些实施例中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以根据电池包的应用和容量进行调节。
图6和图7是作为一个示例的电池包1。参照图6和图7，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
装置
本申请还提供一种装置，所述装置包括本申请所述的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块或电池包可以用作所述装置的电源，也可以作为所述装置的能量存储单元。所述装置可以但不限于是移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等。
所述装置可以根据其使用需求来选择二次电池、电池模块或电池包。
图8是作为一个示例的装置。该装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用二次电池作为电源。
实施例
下述实施例更具体地描述了本申请公开的内容，这些实施例仅仅用于阐述性说明，因为在本申请公开内容的范围内进行各种修改和变化对本领域技术人员来说是明显的。除非另有声明，以下实施例中所报道的所有份、百分比、和比值都是基于重量计，而且实施例中使用的所有试剂都可商购获得或是按照常规方法进行合成获得，并且可直接使用而无需进一步处理，以及实施例中使用的仪器均可商购获得。
实施例1
负极活性材料的制备：
将1g聚丙烯腈加入1L二甲基甲酰胺中，搅拌至聚丙烯腈全部溶解，得到溶液。
将100g氧化亚硅(SiO)加入上述溶液中，搅拌得到混合浆料。
将混合浆料在氩气气氛、180℃下保温干燥2h，得到固体粉末。
称取2g硫粉(纯度＞99.9％)与上述固体粉末混合，在氩气气氛、380℃下热处理3h，冷却后得到负极活性材料。
采用扣式电池测试负极活性材料的容量性能及循环性能，扣式电池的制备包括：
将上述制备的负极活性材料与人造石墨按3:7质量比混合得到负极活性物质。将负极活性物质、导电剂导电炭黑Super P、粘结剂丁苯橡胶(SBR)及羧甲基纤维素钠(CMC)按 88:3:6:3的重量比在适量的去离子水中充分搅拌混合，使其形成均匀的负极浆料；将负极浆料涂覆于负极集流体铜箔上，经干燥、冷压后，得到电极极片，该电极极片可用作二次电池中的负极极片。
以金属锂片作为对电极，采用Celgard 2400隔离膜，并注入电解液，组装得到扣式电池。电解液是将碳酸乙烯酯(EC)、碳酸二甲酯(DMC)、碳酸二乙酯(DEC)按照体积比为1:1:1混合均匀得到有机溶剂，然后将LiPF 6溶解在上述有机溶剂中，并加入添加剂氟代碳酸乙烯酯(FEC)，其中LiPF 6的浓度为1mol/L，FEC在电解液中的质量占比为6％。
实施例2～12及对比例1～4
与实施例1不同的是，调整负极活性材料的制备步骤中的相关参数，详见表1。
测试部分
负极活性材料的测试
1)拉曼光谱分析
采用LabRAM HR Evolution型激光显微拉曼光谱仪测定各实施例及对比例中的负极活性材料，其中，采用波长523nm的固体激光器作为光源，光束直径1.2μm，功率1mW；测量模式采用宏观拉曼；采用CCD探测器。
将负极活性材料粉末压片，在压片上随机取3点进行测试，得到三组测量值取平均值。
2)首次库伦效率及循环性能测试
在25℃、常压环境下，将扣式电池以0.1C倍率恒流放电至电压为0.005V，再以0.05C倍率恒流放电至电压为0.005V，记录此时的放电比容量，即为首次嵌锂容量；之后以0.1C倍率恒流充电至电压为1.5V，记录此时的充电比容量，即为首次脱锂容量。将扣式电池按照上述方法进行50次循环充放电测试，记录每次的脱锂容量。
负极活性材料的首次库伦效率(％)＝首次脱锂容量/首次嵌锂容量×100％
负极活性材料的循环容量保持率(％)＝第50次脱锂容量/首次脱锂容量×100％
表1：负极活性材料的制备参数
Figure PCTCN2020102062-appb-000002
表2：测试结果
Figure PCTCN2020102062-appb-000003
表2中：
I 1是负极活性材料的拉曼光谱中在拉曼位移为900cm -1～960cm -1位置的散射峰的峰强度；
I D是负极活性材料的拉曼光谱中在拉曼位移为1300cm -1～1380cm -1位置的散射峰的峰强度；
I G是负极活性材料的拉曼光谱中在拉曼位移为1520cm -1～1590cm -1位置的散射峰的峰强度；
粒度分布指的是(D v90-D v10)/D v50。
由表2的数据可知，本申请的负极活性材料包括核材料及其至少一部分表面上的聚合物改性包覆层，且在本申请负极活性材料的拉曼光谱中，在拉曼位移为900cm -1～960cm - 1、1300cm -1～1380cm -1及1520cm -1～1590cm -1的位置分别具有散射峰，且在拉曼位移为900cm -1～960cm -1位置的散射峰的峰强度I 1与在拉曼位移为1520cm -1～1590cm -1位置的散射峰的峰强度I G之间满足0.2≤I 1/I G≤0.8，使得本申请的负极活性材料具有较高的首次库伦效率及循环寿命。特别是在拉曼位移为900cm -1～960cm -1位置的散射峰的峰强度I 1与在拉曼位移为1520cm -1～1590cm -1位置的散射峰的峰强度I G之间满足0.22≤I 1/I G≤0.6时，能进一步改善负极活性材料的首次库伦效率及循环寿命。
采用本申请的负极活性材料，能提高二次电池的能量密度、首次库伦效率和循环性能。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到各种等效的修改或替换，这些修改或替换都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以权利要求的保护范围为准。

Claims (21)

  1. 一种负极活性材料，包括核材料及其至少一部分表面上的聚合物改性包覆层；所述核材料包括硅基材料、锡基材料中的一种或几种；所述包覆层包含硫元素和碳元素；
    所述负极活性材料的拉曼光谱中，在拉曼位移为900cm -1～960cm -1、1300cm -1～1380cm -1及1520cm -1～1590cm -1的位置分别具有散射峰，且在拉曼位移为900cm -1～960cm - 1位置的散射峰的峰强度I 1与在拉曼位移为1520cm -1～1590cm -1位置的散射峰的峰强度I G之间满足0.2≤I 1/I G≤0.8。
  2. 根据权利要求1所述的负极活性材料，其中，所述I 1与I G之间满足0.22≤I 1/I G≤0.6。
  3. 根据权利要求1或2所述的负极活性材料，其中，所述负极活性材料的拉曼光谱中拉曼位移为1300cm -1～1380cm -1位置的散射峰的峰强度为I D，所述I D与I G之间满足1.05≤I D/I G≤1.50；可选的，1.1≤I D/I G≤1.45。
  4. 根据权利要求1-3任一项所述的负极活性材料，其中，所述负极活性材料的拉曼光谱中拉曼位移为1300cm -1～1380cm -1位置的散射峰的半峰宽为120cm -1～160cm -1，可选为128cm -1～152cm -1。
  5. 根据权利要求1-4任一项所述的负极活性材料，其中，所述负极活性材料中硫元素的质量百分含量为0.5％～3％，可选为0.8％～1.5％；和/或，
    所述负极活性材料中碳元素的质量百分含量为0.1％～4％，可选为0.5％～3％。
  6. 根据权利要求1-5任一项所述的负极活性材料，其中，所述负极活性材料的X射线衍射光谱中，在衍射角2θ为19°～27°的位置具有衍射峰且半峰宽为4°～12°；可选的，所述半峰宽为5°～10°。
  7. 根据权利要求1-6任一项所述的负极活性材料，其中，所述负极活性材料的粒度分布满足：0.5≤(D v90-D v10)/D v50≤2.5；可选的，0.8≤(D v90-D v10)/D v50≤2.0。
  8. 根据权利要求1-7任一项所述的负极活性材料，其中，
    所述负极活性材料的平均粒径D v50为2μm～12μm，可选为4μm～8μm；和/或，
    所述负极活性材料的比表面积为0.5m 2/g～5m 2/g，可选为0.8m 2/g～3m 2/g。
  9. 根据权利要求1-8任一项所述的负极活性材料，其中，所述负极活性材料的振实密度为0.8g/cm 3～1.3g/cm 3，可选为0.9g/cm 3～1.2g/cm 3；和/或，
    所述负极活性材料在5吨(相当于49KN)压力下测得的压实密度为1.2g/cm 3～ 1.5g/cm 3，可选为1.25g/cm 3～1.45g/cm 3。
  10. 根据权利要求1-9任一项所述的负极活性材料，其中，所述硅基材料选自单质硅、硅氧化合物、硅碳复合物、硅氮化合物、硅合金中的一种或几种；可选的，所述硅基材料选自硅氧化合物；
    所述锡基材料选自单质锡、锡氧化合物、锡合金中的一种或几种。
  11. 一种负极活性材料的制备方法，包括以下步骤：
    提供包含聚合物的溶液；
    将核材料与所述溶液混合，得到混合浆料，其中所述核材料包括硅基材料、锡基材料中的一种或几种；
    将所述混合浆料在惰性气氛下进行干燥，得到固体粉末；
    将所述固体粉末与硫粉混合，并在惰性气氛中进行热处理，得到负极活性材料；
    其中，所述负极活性材料包括核材料及其至少一部分表面上的聚合物改性包覆层，所述包覆层包含硫元素和碳元素，并且所述负极活性材料的拉曼光谱中，在拉曼位移为900cm -1～960cm -1、1300cm -1～1380cm -1及1520cm -1～1590cm -1的位置分别具有散射峰，且在拉曼位移为900cm -1～960cm -1位置的散射峰的峰强度I 1与在拉曼位移为1520cm -1～1590cm -1位置的散射峰的峰强度I G之间满足0.2≤I 1/I G≤0.8。
  12. 根据权利要求11所述的制备方法，其中，所述聚合物包括聚苯胺、聚乙炔、聚丙烯腈、聚苯乙烯、聚氯乙烯和聚乙烯中的一种或几种。
  13. 根据权利要求11或12所述的制备方法，其中，所述包含聚合物的溶液中，所述聚合物的质量与所述溶剂的体积之比为0.1g/L～10g/L；可选的，所述聚合物的质量与所述溶剂的体积之比为1g/L～5g/L。
  14. 根据权利要求11-13任一项所述的制备方法，其中，所述混合浆料中核材料与聚合物的质量比为10～200；可选的，所述混合浆料中核材料与聚合物的质量比为20～100。
  15. 根据权利要求11-14任一项所述的制备方法，其中，所述固体粉末与硫粉混合的步骤满足：所述硫粉的质量与所述固体粉末中聚合物的质量之比为1～5；可选的，所述硫粉的质量与所述固体粉末中聚合物的质量之比为2～4。
  16. 根据权利要求11-15任一项所述的制备方法，其中，所述热处理的温度为200℃～450℃；可选的，所述热处理的温度为300℃～450℃。
  17. 根据权利要求16所述的制备方法，其中，所述热处理的时间为2h～8h；可选的，所述热处理的时间为3h～5h。
  18. 一种二次电池，包括根据权利要求1-10任一项所述的负极活性材料或根据权利要求11-17任一项所述制备方法得到的负极活性材料。
  19. 一种电池模块，包括根据权利要求18所述的二次电池。
  20. 一种电池包，包括根据权利要求19所述的电池模块。
  21. 一种装置，包括根据权利要求18所述的二次电池、根据权利要求19所述的电池模块、或根据权利要求20所述的电池包中的至少一种。
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114094077A (zh) * 2021-11-15 2022-02-25 珠海冠宇电池股份有限公司 一种负极材料及包含该负极材料的负极片

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113097433B (zh) * 2021-03-30 2022-11-01 宁德新能源科技有限公司 电化学装置及电子设备
CN115842108A (zh) * 2021-09-28 2023-03-24 宁德时代新能源科技股份有限公司 负极活性材料及其制备方法、具备其的二次电池
CN115440968A (zh) * 2022-06-24 2022-12-06 宁德新能源科技有限公司 负极活性材料、二次电池和电子装置
CN115911261A (zh) * 2022-11-29 2023-04-04 宁德新能源科技有限公司 负极极片、二次电池和用电装置
CN116888761A (zh) * 2023-03-03 2023-10-13 宁德时代新能源科技股份有限公司 硅基负极活性材料、二次电池及用电装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101210119A (zh) * 2006-12-29 2008-07-02 比亚迪股份有限公司 一种含硅复合材料及其制备方法和用途
CN103456928A (zh) * 2013-09-02 2013-12-18 东莞新能源科技有限公司 锂离子电池用复合阳极材料及其制备方法
CN105633368A (zh) * 2015-12-31 2016-06-01 深圳市贝特瑞新能源材料股份有限公司 一种锂离子电池负极材料及其制备方法
CN109103441A (zh) * 2018-09-10 2018-12-28 江苏塔菲尔新能源科技股份有限公司 含硅基材料的改性复合材料、其制备方法及在锂离子电池的用途
CN109301184A (zh) * 2018-09-10 2019-02-01 江苏塔菲尔新能源科技股份有限公司 含硅基材料的改性复合材料、其制备方法及在锂离子电池的用途
US20190074508A1 (en) * 2017-09-01 2019-03-07 SiNode Systems, Inc. Composite anode material including encapsulated buffered active material particles

Family Cites Families (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100570648B1 (ko) * 2004-01-26 2006-04-12 삼성에스디아이 주식회사 리튬 이차 전지용 음극 활물질, 그의 제조 방법 및 그를포함하는 리튬 이차 전지
KR101708360B1 (ko) 2011-10-05 2017-02-21 삼성에스디아이 주식회사 음극 활물질 및 이를 채용한 리튬 전지
JP5982811B2 (ja) * 2011-12-20 2016-08-31 ソニー株式会社 二次電池用活物質、二次電池および電子機器
JP5935732B2 (ja) * 2012-03-27 2016-06-15 Tdk株式会社 負極活物質、これを含む電極、当該電極を用いるリチウムイオン二次電池
DE102012209635A1 (de) * 2012-06-08 2013-12-12 Robert Bosch Gmbh Verfahren zum Herstellen eines Polyacrylnitril-Schwefel-Kompositwerkstoffs
JP2014096326A (ja) 2012-11-12 2014-05-22 Toyota Industries Corp 二次電池用負極活物質、並びにこれを用いた負極及び二次電池
WO2014119238A1 (ja) * 2013-01-30 2014-08-07 三洋電機株式会社 非水電解質二次電池用負極活物質、当該負極活物質を用いた非水電解質二次電池用負極、及び当該負極を用いた非水電解質二次電池
CN104241612A (zh) * 2013-06-14 2014-12-24 中国科学院大连化学物理研究所 一种硫化聚合物包覆的硫/碳复合材料及其制备方法
CN105612640B (zh) 2013-10-02 2017-12-12 尤米科尔公司 碳涂覆的电化学活性粉末
CN104577050B (zh) * 2013-10-17 2017-07-07 清华大学 锂离子电池电极活性物质及其制备方法
JP6301142B2 (ja) * 2014-01-31 2018-03-28 信越化学工業株式会社 非水電解質二次電池用負極材及び非水電解質二次電池用負極材の製造方法並びに非水電解質二次電池
KR102189548B1 (ko) * 2014-06-02 2020-12-14 삼성에스디아이 주식회사 리튬 이차 전지용 음극 활물질, 및 이를 포함하는 리튬 이차 전지
JP2016152077A (ja) * 2015-02-16 2016-08-22 信越化学工業株式会社 非水電解質二次電池用負極活物質及び非水電解質二次電池、並びに非水電解質二次電池用負極材の製造方法
JP6403638B2 (ja) * 2015-06-15 2018-10-10 信越化学工業株式会社 非水電解質二次電池用負極活物質、非水電解質二次電池用負極、及び非水電解質二次電池、並びに非水電解質二次電池用負極材の製造方法
CN105226246B (zh) * 2015-09-08 2017-08-29 武汉理工大学 石墨烯包覆P@SnO2核壳量子点电极材料及其制备方法和应用
KR102246770B1 (ko) * 2016-07-19 2021-04-30 삼성에스디아이 주식회사 음극 활물질, 이를 포함하는 리튬 전지, 및 상기 음극 활물질의 제조방법
KR102617731B1 (ko) * 2018-01-03 2024-01-05 삼성전자주식회사 실리콘 함유 복합체, 그 제조방법, 이를 이용한 탄소 복합체, 이를 포함한 전극, 리튬 전지 및 전자소자
CN109256554B (zh) * 2018-09-28 2020-08-28 河南科技学院 一种硫化聚合物复合材料及其制备方法和应用

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101210119A (zh) * 2006-12-29 2008-07-02 比亚迪股份有限公司 一种含硅复合材料及其制备方法和用途
CN103456928A (zh) * 2013-09-02 2013-12-18 东莞新能源科技有限公司 锂离子电池用复合阳极材料及其制备方法
CN105633368A (zh) * 2015-12-31 2016-06-01 深圳市贝特瑞新能源材料股份有限公司 一种锂离子电池负极材料及其制备方法
US20190074508A1 (en) * 2017-09-01 2019-03-07 SiNode Systems, Inc. Composite anode material including encapsulated buffered active material particles
CN109103441A (zh) * 2018-09-10 2018-12-28 江苏塔菲尔新能源科技股份有限公司 含硅基材料的改性复合材料、其制备方法及在锂离子电池的用途
CN109301184A (zh) * 2018-09-10 2019-02-01 江苏塔菲尔新能源科技股份有限公司 含硅基材料的改性复合材料、其制备方法及在锂离子电池的用途

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3944371A4 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114094077A (zh) * 2021-11-15 2022-02-25 珠海冠宇电池股份有限公司 一种负极材料及包含该负极材料的负极片

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