WO2024183545A1 - 负极材料、负极片和电池 - Google Patents

负极材料、负极片和电池 Download PDF

Info

Publication number
WO2024183545A1
WO2024183545A1 PCT/CN2024/078274 CN2024078274W WO2024183545A1 WO 2024183545 A1 WO2024183545 A1 WO 2024183545A1 CN 2024078274 W CN2024078274 W CN 2024078274W WO 2024183545 A1 WO2024183545 A1 WO 2024183545A1
Authority
WO
WIPO (PCT)
Prior art keywords
silicon
carbon
negative electrode
carbon particles
electrode material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2024/078274
Other languages
English (en)
French (fr)
Inventor
李瑞年
薛佳宸
汪辉
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Zhuhai Cosmx Battery Co Ltd
Original Assignee
Zhuhai Cosmx Battery Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Zhuhai Cosmx Battery Co Ltd filed Critical Zhuhai Cosmx Battery Co Ltd
Publication of WO2024183545A1 publication Critical patent/WO2024183545A1/zh
Priority to US19/274,916 priority Critical patent/US20250349830A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • 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
    • 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
    • H01M4/134—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
    • 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
    • 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
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • 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 field of batteries, and in particular to a negative electrode material, a negative electrode sheet comprising the negative electrode material, and a battery comprising the negative electrode material.
  • lithium-ion batteries are increasingly used in portable mobile electronic devices such as laptops and smart phones, and people's requirements for battery energy density are also getting higher and higher.
  • silicon material has poor conductivity and large volume expansion during the cycle.
  • carbon is compounded with carbon to form silicon-carbon material to alleviate volume expansion, improve conductivity, and improve battery cycle performance, but there is no significant improvement.
  • the purpose of the present disclosure is to overcome the above-mentioned problems existing in the prior art, and to provide a negative electrode material, a negative electrode sheet including the negative electrode material, and a battery including the negative electrode material.
  • the negative electrode material disclosed in the present disclosure includes silicon-carbon particles with a hollow structure, and the mass content of silicon in the silicon-carbon particles and the ratio of the cavity radius of the hollow structure to the radius of the silicon-carbon particles have a specific relationship, so that the negative electrode material can effectively alleviate the expansion of the silicon material during the battery cycle, improve the cycle performance of the battery, and can effectively improve the conductivity of the negative electrode material.
  • the present disclosure provides a negative electrode material in a first aspect, wherein the negative electrode material comprises silicon carbon particles, wherein the silicon carbon particles have a hollow structure, wherein the hollow structure comprises a cavity and a shell surrounding the cavity, wherein the shell comprises a silicon carbon layer; wherein the mass content ⁇ (unit: %) of silicon in the silicon carbon particles and the ratio a (unit: %) of the radius of the cavity to the radius of the silicon carbon particles satisfy
  • the second aspect of the present disclosure provides a negative electrode sheet, wherein the negative electrode sheet comprises the negative electrode sheet described in the first aspect of the present disclosure Negative electrode material.
  • a third aspect of the present disclosure provides a battery, which includes the negative electrode material described in the first aspect of the present disclosure and/or the negative electrode sheet described in the second aspect of the present disclosure.
  • the present disclosure has at least the following advantages compared with the prior art:
  • the negative electrode material disclosed herein includes silicon-carbon particles having a hollow structure, which can alleviate the expansion of silicon;
  • the negative electrode material disclosed in the present invention includes silicon-carbon particles, which include a shell and a cavity formed by the shell.
  • the mass content of silicon in the silicon-carbon particles and the ratio of the radius of the cavity to the radius of the silicon-carbon particles have a specific relationship, which can further alleviate the volume expansion of silicon.
  • any values of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values.
  • the endpoint values of each range, the endpoint values of each range and the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this article.
  • FIG. 1 is a schematic diagram of a hollow structure described in the present disclosure.
  • FIG. 2 shows an energy spectrum element distribution diagram of the silicon-carbon particles described in an example of the present disclosure.
  • FIG3 is a comparison diagram of the XRD spectrum of the silicon-carbon particles in an example of the present disclosure and the XRD spectrum of the silicon-carbon material in a comparative example.
  • FIG. 4 is a schematic diagram of the hollow structure described in the present disclosure.
  • FIG. 5 is a SEM image of the silicon-carbon particles prepared in Example 1 of the present disclosure.
  • FIG. 6 is a SEM image of the silicon-carbon material prepared in Comparative Example 1 of the present disclosure.
  • FIG. 7 shows the point scanning result of the energy spectrum element distribution diagram of the silicon-carbon particles prepared in Example 1 of the present disclosure.
  • FIG8 shows the point scanning result of the energy spectrum element distribution diagram of the silicon-carbon particles prepared in Example 5 of the present disclosure.
  • the present disclosure provides a negative electrode material, which may include silicon-carbon particles, the silicon-carbon particles having a hollow structure, and the hollow structure may include a cavity and a shell surrounding the cavity.
  • FIG1 is a schematic diagram of the hollow structure in the present disclosure, in which the hollow structure includes a cavity 2 and a shell 1 surrounding the cavity 2 (wherein r1 and r2 marked with dashed lines in FIG1 represent the radius of the cavity and the radius of the silicon-carbon particles, respectively).
  • the shell may include a silicon carbon layer.
  • the shell is a silicon carbon layer.
  • the ratio of the mass content of silicon in the silicon-carbon particles ⁇ (unit: %) to the radius of the cavity to the radius of the silicon-carbon particles a (unit: %) satisfies
  • Example 1 of the present disclosure The mass content of silicon in the silicon-carbon particles is ⁇ 13%, a is 49.26%, and the calculated value is is 0.13, which satisfies
  • the ratio of the radius of the cavity to the radius of the silicon-carbon particle refers to the ratio of the radius of the cavity to the radius of the silicon-carbon particle.
  • the mass content ⁇ of silicon in the silicon-carbon particles can be 0.01%-90%, for example, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90%.
  • the mass content ⁇ of silicon in the silicon-carbon particles is 5%-20%.
  • the inventors of the present disclosure have discovered that when the mass content of silicon in the silicon-carbon particles is within a specific range, the battery can have both energy density and cycle performance.
  • the mass content ⁇ of silicon in the silicon-carbon particles can be measured by conventional methods in the art, such as using a carbon-sulfur analyzer.
  • the radius of the cavity may be 0.05 ⁇ m-14.5 ⁇ m, for example 0.05 ⁇ m, 0.1 ⁇ m, 0.5 ⁇ m, 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 10 ⁇ m, 11 ⁇ m, 12 ⁇ m, 13 ⁇ m, 14 ⁇ m or 14.5 ⁇ m.
  • the ratio a of the radius of the cavity (r 1 ) to the radius of the silicon-carbon particle (r 2 ) may be 0.3%-97%, for example, 0.3%, 0.5%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 97%.
  • the radius (r 1 ) of the cavity is 0.5 ⁇ m-4 ⁇ m.
  • the radius of the silicon-carbon particles and the radius of the cavity can be tested by conventional methods in the art, such as by scanning electron microscopy (SEM).
  • SEM scanning electron microscopy
  • 20 silicon-carbon particles are randomly selected, and the radius of the silicon-carbon particles and the radius of the cavity are measured using a measuring tool, and the average value is taken.
  • the radius of the silicon-carbon particles and the radius of the cavity are the radius of the circle; when the silicon-carbon particles and the cavity are non-standard circles (such as ellipses) in the SEM image, the radius of the silicon-carbon particles and the radius of the cavity are equivalent to the radius of a standard circle with the same area as the non-standard circle.
  • the carbon in the silicon carbon particles includes porous carbon.
  • the pore size of the porous carbon can be 0.001nm-50nm, for example, 0.001nm, 0.005nm, 0.01nm, 0.05nm, 0.1nm, 0.2nm, 0.3nm, 0.4nm, 0.5nm, 0.6nm, 0.7nm, 0.8nm, 0.9nm, 1nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm or 50nm.
  • the pore size of the porous carbon is 0.005 nm-20 nm.
  • the pore size of the porous carbon is 0.01 nm-10 nm.
  • the inventors of the present disclosure have found that when the pore size of the porous carbon is within a specific range, the volume expansion of the silicon material It has a good relieving effect on swelling.
  • the pore size of the porous carbon can be tested by conventional methods in the art, for example, referring to the national standard GB/T 19587-2017; for example, using the equipment Micromeritics TristarII3020.
  • the porous carbon includes micropores and/or mesopores.
  • the porous carbon has abundant micropores and/or mesopores, and loading silicon materials in the micropores and/or mesopores of the porous carbon can not only form an interconnected conductive network and enhance the electronic connectivity between silicon materials, but also reduce the agglomeration of silicon materials and provide a buffer space for the volume expansion of silicon materials.
  • n 1, 2, 3, 4, and 5; for example Equal to 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50%.
  • n 1, 2, 3, 4 and 5.
  • n 1, 2, 3, 4 and 5.
  • the mass of silicon and the mass of carbon at random points on the silicon-carbon layer of the silicon-carbon particles can be obtained by performing an energy spectrum element distribution analysis test on the silicon-carbon particles, and performing a point scanning test on the energy spectrum element distribution map of the silicon-carbon particles obtained by the test. Specifically: in the energy spectrum element distribution map of the silicon-carbon particles, the position of the silicon-carbon layer is found, 5 points are randomly selected from the positions of the above-mentioned silicon-carbon layer, and a point scanning test is performed, and then each point is subjected to element analysis, so that the mass content of silicon and the mass content of carbon at each point can be obtained, wherein the point scanning area of the point is approximately a circle with a diameter of 300nm. Shape area.
  • the inventors of the present disclosure discovered that by randomly selecting five points on the silicon-carbon layer of the silicon-carbon particles and averaging the ratio of the mass of silicon to the mass of carbon at the five points, the difference between the ratio of the mass of silicon to the mass of carbon at each of the five random points and the average value is obtained.
  • the ratio of the difference between the five random points and the average value is within a certain range, the distribution of the silicon and the carbon is more uniform, which can enhance the conductive network between the silicon and between the silicon and the carbon, enhance the conductivity of the silicon-carbon particles, and thereby enhance the rate performance of the battery.
  • the silicon in the silicon-carbon particles is uniformly distributed in the pores of the porous carbon.
  • FIG2 is an energy spectrum element distribution diagram of the silicon-carbon particles in an example of the present disclosure. It can be seen from FIG2 that the silicon and the carbon are uniformly distributed.
  • the median particle size Dv50 of the silicon carbon particles can be 2 ⁇ m-30 ⁇ m, for example 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 10 ⁇ m, 11 ⁇ m, 12 ⁇ m, 13 ⁇ m, 14 ⁇ m, 15 ⁇ m, 16 ⁇ m, 17 ⁇ m, 18 ⁇ m, 19 ⁇ m, 20 ⁇ m, 21 ⁇ m, 22 ⁇ m, 23 ⁇ m, 24 ⁇ m, 25 ⁇ m, 26 ⁇ m, 27 ⁇ m, 28 ⁇ m, 29 ⁇ m or 30 ⁇ m.
  • the median particle size Dv50 of the silicon carbon particles is 5 ⁇ m-10 ⁇ m.
  • the median particle size Dv50 of the silicon-carbon particles can be measured by conventional methods in the art, such as a laser particle size analyzer.
  • the inventors of the present disclosure have found that when the median particle size Dv50 of the silicon-carbon particles is within a certain range, the silicon-carbon particles have better kinetic properties, less side reactions with the electrolyte, and are easier to operate during the coating process.
  • the thickness of the silicon carbon layer may be 0.5 ⁇ m-5 ⁇ m, for example, 0.5 ⁇ m, 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m or 5 ⁇ m.
  • the ratio of the thickness of the silicon carbon layer to the radius of the silicon carbon particle can be 3%-98%, for example 3%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 98%.
  • the inventors of the present disclosure have discovered that when the ratio of the thickness of the silicon carbon layer to the radius of the silicon carbon particles is within a specific range, the expansion of the silicon carbon particles can be effectively alleviated.
  • the thickness of the silicon carbon layer is 1 ⁇ m-4.5 ⁇ m.
  • the inventors of the present disclosure have discovered that when the thickness of the silicon carbon layer is within a specific range, the expansion of the silicon carbon particles can be effectively alleviated.
  • the thickness of the silicon carbon layer refers to the thickness of a single layer of the silicon carbon layer.
  • the thickness of the silicon carbon layer can be tested by conventional methods in the art, such as SEM.
  • SEM scanning electron microscope
  • 20 silicon carbon particles are randomly selected, and the thickness of the silicon carbon layer is measured using a measuring tool (at least five points of the silicon carbon layer of each silicon carbon particle are randomly selected for measurement and the average value is taken).
  • the silicon in the silicon-carbon particles includes amorphous silicon.
  • the inventors of the present disclosure have discovered that when the silicon is amorphous silicon, the volume strain of the silicon during battery cycling is smaller, thereby improving the battery's cycling performance.
  • the silicon in the silicon-carbon particles is amorphous silicon.
  • FIG3 a comparison diagram of the XRD spectrum of the silicon-carbon particles in an example of the present disclosure and the XRD spectrum of the silicon-carbon material in a pair of ratios is shown, wherein FIG3 (a) is the XRD spectrum of the silicon-carbon particles in an example of the present disclosure, and FIG3 (b) is the XRD spectrum of the silicon-carbon material in a pair of ratios of the present disclosure. It can be seen from the figure that the silicon in the silicon-carbon particles described in the present disclosure includes amorphous silicon.
  • the median particle size Dv50 of the silicon can be 0.01nm-150nm, for example 0.01nm, 0.05nm, 0.1nm, 0.5nm, 1nm, 2nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm, 110nm, 120nm, 130nm, 140nm or 150nm.
  • the median particle size Dv50 of the silicon is 1 nm-40 nm.
  • the median particle size Dv50 of the silicon is 2 nm-10 nm.
  • the inventors of the present disclosure have discovered that when the median particle size Dv50 of silicon in the silicon-carbon particles is controlled within a certain range, the volume expansion of the silicon can be effectively reduced, thereby effectively improving the cycle performance of the battery.
  • the shell may further include a coating layer on the outer surface of the silicon carbon layer; as shown in FIG4 , which is a schematic diagram of the hollow structure described in the present disclosure, in FIG4 , the shell 1 includes a silicon carbon layer 1-2 and a coating layer 1-1 on the outer surface of the silicon carbon layer 1-2 (wherein r1 and r2 marked with dotted lines in FIG4 represent the radius of the cavity and the radius of the silicon carbon particle, respectively).
  • the inventors of the present disclosure have discovered that providing a coating layer on the outer surface of the silicon-carbon layer can protect the silicon-carbon layer, thereby further improving the cycle performance and rate performance of the battery.
  • the thickness of the coating layer can be 20nm-300nm, for example, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm, 150nm, 200nm, 250nm or 300nm.
  • the inventors of the present disclosure have found that when the thickness of the coating layer is within a specific range, the cycle performance and rate performance of the battery can be improved.
  • the ratio of the thickness of the coating layer to the radius of the silicon carbon particle can be 0.1%-30%, for example 0.1%, 0.3%, 0.5%, 1%, 5%, 10%, 15%, 20%, 25% or 30%.
  • the inventors of the present disclosure have discovered that when the ratio of the thickness of the coating layer to the radius of the silicon-carbon particles is within a specific range, the cycle performance and rate performance of the battery can be improved.
  • the coating layer has a thickness of 50 nm to 70 nm.
  • the thickness of the coating layer refers to the thickness of a single layer of the coating layer.
  • the thickness of the coating layer can be tested by conventional methods in the art, such as SEM.
  • SEM scanning electron microscope
  • 20 silicon-carbon particles are randomly selected, and the thickness of the coating layer is measured using a measuring tool (at least five points of the coating layer of each silicon-carbon particle are randomly selected for measurement and the average value is taken).
  • the coating layer may include a carbon layer.
  • the coating layer is a carbon layer.
  • the electrical conductivity of the silicon carbon particles may be 10S/cm-500S/cm, for example, 10S/cm, 20S/cm, 30S/cm, 40S/cm, 50S/cm, 60S/cm, 70S/cm, 80S/cm, 90S/cm, 100S/cm, 150S/cm, 200S/cm, 250S/cm, 300S/cm, 350S/cm, 400S/cm, 450S/cm or 500S/cm.
  • the electrical conductivity of the silicon carbon particles is 20 S/cm-320 S/cm.
  • the electrical conductivity of the silicon-carbon particles can be tested according to the method of GB/T 24533-2019.
  • the inventors of the present disclosure have discovered that when the electrical conductivity of the silicon-carbon particles is within a certain range, the rate performance of the battery can be further improved.
  • the specific surface area of the silicon-carbon particles can be 0.5 m 2 /g-25 m 2 /g, for example, 0.5 m 2 /g, 1 m 2 /g, 2 m 2 /g, 3 m 2 /g, 4 m 2 /g, 5 m 2 /g, 6 m 2 /g, 7 m 2 /g, 8 m 2 /g, 9 m 2 /g, 10 m 2 /g, 11 m 2 / g, 12 m 2 /g, 13 m 2 /g, 14 m 2 /g, 15 m 2 /g, 16 m 2 /g, 17 m 2 /g, 18 m 2 /g, 19 m 2 /g, 20 m 2 / g, 21 m 2 /g, 22 m 2 /g, 23 m 2 /g, 24 m 2 /g or 25 m 2 /g.
  • the specific surface area of the silicon-carbon particles can be tested according to the method of GB/T 24533-2019.
  • the inventors of the present disclosure have found that when the specific surface area of the silicon-carbon particles is within a specific range, the battery has better cycle performance and rate performance.
  • the true density of the silicon carbon particles may be 1 g/cm 3 -3 g/cm 3 , such as 1 g/cm 3 , 1.5 g/cm 3 , 2 g/cm 3 , 2.5 g/cm 3 or 3 g/cm 3 .
  • the true density of the silicon carbon particles is 1.1 g/cm 3 -2.2 g/cm 3 .
  • the true density of the silicon-carbon particles can be tested according to the method of GB/T 24533-2019.
  • the inventors of the present disclosure have discovered that when the true density of the silicon-carbon particles is within a specific range, the battery has better energy density and cycle performance.
  • the negative electrode active material disclosed herein includes silicon-carbon particles with a hollow structure, which can effectively alleviate the expansion of silicon during battery cycling, improve the conductivity of the silicon-carbon particles, and further improve the cycle performance and rate performance of the battery.
  • the present disclosure also provides a method for preparing the silicon-carbon particles, the method comprising at least: Silicon material is vapor deposited in porous carbon with a hollow structure.
  • the porous carbon with a hollow structure can be commercially available or prepared.
  • the porous carbon with a hollow structure is obtained by preparation, and the preparation method at least includes: performing a first sintering of the biomass porous carbon material with a hollow structure under an inert atmosphere.
  • the biomass porous carbon material with a hollow structure can be selected from the biomass porous carbon material with a hollow structure conventionally used in the art, for example, selected from pollen or starch.
  • the composition of biomass porous carbon material includes carbon element, hydrogen element and oxygen element, among which carbon element, as a skeleton, accounts for a relatively large proportion of the mass in the biomass porous carbon material.
  • the inert atmosphere may be any inert atmosphere conventionally used in the art, for example, at least one selected from nitrogen, argon, helium, neon and krypton.
  • the temperature of the first sintering may be 400° C.-1300° C., such as 400° C., 500° C., 600° C., 700° C., 800° C., 900° C., 1000° C., 1100° C., 1200° C. or 1300° C.
  • the time of the first sintering may be 1 h-24 h, such as 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h, 21 h, 22 h, 23 h or 24 h.
  • the vapor deposition may be performed in a vapor deposition furnace, that is, the porous carbon having a hollow structure is placed in a first vapor deposition furnace.
  • the vapor deposition conditions may include: introducing a silicon source and a protective gas.
  • the silicon source includes at least one of monosilane, disilane, dichlorosilane, trichlorosilane, and silicon tetrachloride.
  • the flow rate of the silicon source may be 0.5 L/min-5 L/min.
  • the protective gas includes at least one of nitrogen, argon, helium, neon and krypton.
  • the temperature of the vapor deposition may be 300° C.-1000° C., for example, 300° C., 400° C., 500° C., 600° C., 700° C., 800° C., 900° C. or 1000° C.
  • the time of the vapor deposition may be 0.25 h-12 h, for example, 0.25 h, 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h or 12 h.
  • the method for preparing the silicon-carbon particles may further include: coating with conductive carbon after vapor-depositing the silicon material.
  • the conductive carbon coating may include vapor deposition coating.
  • the vapor deposition coating at least includes the following method: placing the material after the vapor deposition of silicon material in a second vapor deposition furnace, introducing a carbon source and nitrogen gas, and performing carbon coating.
  • the carbon source may include methane or acetylene.
  • the carbon coating temperature may be 350° C.-1000° C., such as 350° C., 400° C., 500° C., 600° C., 700° C., 800° C., 900° C. or 1000° C.
  • the carbon coating time may be 0.5 h-12 h, such as 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h or 12 h.
  • the preparation method of the silicon-carbon particles provided in the present disclosure has an easy-to-control process route, and the silicon material can be evenly distributed in the porous carbon material by vapor deposition.
  • the silicon material can be further evenly distributed in the porous carbon material by controlling the silicon source flow rate during the vapor deposition process as well as the time and temperature of the vapor deposition.
  • the use of biomass carbon materials has a simple processing method and is environmentally friendly.
  • a second aspect of the present disclosure provides a negative electrode sheet, which includes the negative electrode material described in the first aspect of the present disclosure.
  • the negative electrode sheet comprises a negative electrode current collector and a coating disposed on at least one side of the surface of the negative electrode current collector, wherein the coating comprises the negative electrode material described in the first aspect of the present disclosure.
  • the coating may further include additives conventionally used in coatings, such as conductive agents and binders.
  • the coating layer includes the negative electrode material, the conductive agent, and the binder.
  • the conductive agent may include a conductive agent commonly used in the art, for example, the conductive agent is selected from at least one of SuperP, acetylene black and Ketjen black.
  • the binder may include a binder commonly used in the art, for example, the binder is selected from carboxymethyl At least one of sodium cellulose, carboxymethyl cellulose, polyvinylidene fluoride and styrene-butadiene rubber.
  • the content of the negative electrode material can be 80-99 weight % (for example, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99 weight %)
  • the content of the conductive agent can be 0.5-10 weight % (for example, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 or 0.5 weight %)
  • the content of the binder can be 0.5-10 weight % (for example, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 or 0.5 weight %).
  • the content of the negative electrode material is 95-99% by weight
  • the content of the conductive agent is 0.5-2.5% by weight
  • the content of the binder is 0.5-2.5% by weight.
  • the content of the negative electrode material is 96-98 weight %
  • the content of the conductive agent is 1-2 weight %
  • the content of the binder is 1-2 weight %.
  • a third aspect of the present disclosure provides a battery, which includes the negative electrode material described in the first aspect of the present disclosure or the negative electrode sheet described in the second aspect of the present disclosure.
  • the components of the battery other than the negative electrode can all be conventionally selected in the art.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer coated on at least one side of the positive electrode current collector, and the positive electrode active material layer includes a positive electrode active material.
  • the positive electrode active material can be selected conventionally in the art.
  • the positive electrode active material is selected from at least one of lithium cobalt oxide (LCO), nickel cobalt manganese ternary material (NCM), nickel cobalt aluminum ternary material (NCA), nickel cobalt manganese aluminum quaternary material (NCMA), lithium iron phosphate (LFP), lithium manganese phosphate (LMP), lithium vanadium phosphate (LVP), lithium manganese oxide (LMO), lithium nickel oxide, nickel manganese oxide binary material, lithium-rich manganese-based and lithium iron manganese phosphate.
  • LCO lithium cobalt oxide
  • NCM nickel cobalt manganese ternary material
  • NCA nickel cobalt aluminum ternary material
  • NCMA nickel cobalt manganese aluminum quaternary material
  • LFP lithium iron phosphate
  • LMP lithium manganese phosphate
  • LVP lithium vanadium phosphate
  • LMO lithium manganese oxide
  • lithium nickel oxide nickel manganes
  • the positive electrode active material may further include doped and/or coated positive electrode active materials.
  • the battery can be assembled in a conventional manner in the art.
  • the battery can be a liquid electrolyte battery, a semi-solid battery, or an all-solid battery.
  • step S2 The corn starch powder obtained in step S1 is placed in a high temperature furnace and sintered for 4 hours under a nitrogen atmosphere at a sintering temperature of 900°C and a heating rate of 5°C/min to obtain porous carbon;
  • step S3 The porous carbon obtained in step S2 was crushed, 0.5 kg of the carbon was passed through a 200-mesh sieve and placed in a rotatable tube furnace for vapor deposition of silicon material at a rotation speed of 1 r/min, high-purity nitrogen was introduced at a nitrogen flow rate of 3 L/min, the temperature was raised to 550°C, the heating rate was 5°C/min, the nitrogen flow rate was kept constant, monosilane with a purity of 99.99% was introduced at a monosilane flow rate of 2.0 L/min, and the time for introducing monosilane was 1 h;
  • step S4 The material obtained in step S3 is subjected to spray granulation treatment, passed through a 500-mesh sieve, and then placed in a CVD furnace for carbon coating, high-purity nitrogen is introduced, the temperature is raised to 900°C, the heating rate is 5°C/min, and then acetylene with a purity of 99.99% is introduced, the flow ratio of acetylene to nitrogen is 1:1, and the ventilation time is 3h.
  • the obtained material is then passed through a 500-mesh sieve and demagnetized to obtain the silicon-carbon particles, wherein the demagnetization treatment is performed in an electromagnetic powder demagnetizer;
  • the silicon-carbon particles, conductive carbon black and styrene-butadiene rubber obtained in step (1) are added with deionized water in a mass ratio of 95:2:3, stirred, and then passed through a 200-mesh sieve to obtain a negative electrode slurry with a solid content of 45 wt %.
  • the negative electrode slurry is coated on a copper foil using a transfer coater, dried at 120° C., and rolled to obtain a negative electrode sheet;
  • Lithium cobalt oxide, carbon nanotubes, acetylene black and polyvinylidene fluoride were added into a stirring tank in a mass ratio of 96:1.2:1.5:1.3, and N-methylpyrrolidone was added and stirred, and then passed through a 200-mesh sieve to obtain a positive electrode slurry with a solid content of 75wt%, and the positive electrode slurry was coated on an aluminum foil using a coating machine, dried at 120°C, and rolled to obtain a positive electrode sheet;
  • the negative electrode sheet obtained in step (2), the positive electrode sheet obtained in step (3) and the separator are wound to form a core (width of 62 mm), which is packaged with an aluminum-plastic film.
  • an electrolyte 1.0 mol/L LiPF 6 , an organic solvent is a mixture of ethylene carbonate (EC), diethyl carbonate (DEC) and ethyl methyl carbonate (EMC) in a mass ratio of 2:1:2) is injected, and a battery is obtained after hot pressing.
  • Examples 2-6 and Comparative Example 2 are carried out with reference to Example 1, except that the silicon-carbon particles are changed by changing the parameters of the silicon-carbon particle preparation process, as shown in Table 1, wherein the median particle size Dv50 of silicon in Examples 1-6 of the present disclosure is all within the range of 2nm-10nm (including both end points), the pore size of the porous carbon is all within the range of 0.01nm-10nm (including both end points), and the silicon in the silicon-carbon particles is amorphous silicon.
  • the silicon-carbon particles prepared in Example 1 and the silicon-carbon material prepared in Comparative Example 1 were subjected to SEM tests, wherein the SEM image of the silicon-carbon particles prepared in Example 1 is shown in FIG. 5 , as can be seen from FIG. 5 , the silicon-carbon particles have a hollow structure, and the distribution of silicon and carbon in the silicon-carbon layer is very uniform; the SEM image of the silicon-carbon material prepared in Comparative Example 1 is shown in FIG. 6 , as can be seen from FIG. 6 , the distribution of silicon and carbon is uneven.
  • Example 1 and Example 5 were subjected to energy spectrum element distribution analysis test-point scanning test, and the test results are shown in Figures 7 and 8, wherein Figure 7 is the energy spectrum element distribution analysis test-point scanning test result of Example 1, and Figure 8 is the energy spectrum element distribution analysis test-point scanning test result of Example 5; It can be seen from the figure that in Example 1, About 24.7%, in Example 5, About 47%.
  • the silicon-carbon particles prepared in the embodiment and the silicon-carbon material prepared in the comparative example were added with conductive carbon black and styrene-butadiene rubber, wherein the mass ratio of silicon-carbon particles/silicon-carbon material, conductive carbon black and styrene-butadiene rubber was 97:1:2, deionized water was added and stirred, and then passed through a 200-mesh sieve to obtain a negative electrode slurry with a solid content of 45wt%, and the negative electrode slurry was coated on a copper foil using a transfer coater, dried at 120°C, and rolled to obtain a negative electrode sheet, which was tested for a lithium half-cell.
  • the specific test method was as follows: 0.05C constant current discharge to 5mV, standing for 10min, 0.025C constant current discharge to 5mV; 0.05C constant current charge to 1.5V, and the test results were recorded in Table 2.
  • the batteries prepared in the examples and comparative examples were subjected to a 1C/1C cycle test at a test temperature of 25°C.
  • the test results are recorded in Table 2.
  • the batteries prepared in the examples and comparative examples were subjected to 0.5C constant current constant voltage charging/0.2C discharge testing at 25°C to test the battery discharge capacity.
  • Energy density discharge capacity ⁇ average voltage/(thickness ⁇ width ⁇ height). The test results are recorded in Table 2.
  • discharge rate 0.2C/1C/2C/3C/4C
  • Steps 4 to 7 are repeated until all rate discharge tests are completed, and the test results are recorded in Table 2.
  • the battery prepared by the negative electrode material of the present invention has significantly improved conductivity, 100T capacity retention rate and rate performance, and significantly reduced expansion rate.
  • the hollow structure of the negative electrode material of the present invention significantly improves the cycle performance and rate performance of the battery; compared with Comparative Example 2, Example 1 of the present invention satisfies The capacity retention rate and The rate performance is significantly improved and the expansion rate is significantly reduced.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

本公开涉及电池领域，具体涉及负极材料、包括该负极材料的负极片以及包括该负极材料的电池。所述负极材料包括硅碳颗粒，所述硅碳颗粒具有中空结构，所述中空结构包括空腔和围绕所述空腔的外壳，所述外壳包括硅碳层；所述硅碳颗粒中硅的质量含量ω与所述空腔的半径占所述硅碳颗粒的半径的比值a满足式（1）。本公开的负极材料包括具有中空结构的硅碳颗粒，所述硅碳颗粒中硅的质量含量与所述空腔的半径占所述硅碳颗粒的半径的比值具有特定的关系，使得所述负极材料可以有效缓解硅材料在电池循环过程中的膨胀，提升电池的循环性能，并且可以有效提高负极材料的导电性。

Description

负极材料、负极片和电池 技术领域
本公开涉及电池领域，具体涉及负极材料、包括该负极材料的负极片以及包括该负极材料的电池。
背景技术
随着锂离子电池技术的迅速发展，锂离子电池在笔记本电脑、智能手机等便携式移动电子设备上的应用越来越广泛，人们对电池能量密度的要求也越来越高。
目前，石墨掺混硅负极作为电池能量密度提升的主要措施，但是，硅材料导电性差，且循环过程中的体积膨胀较大。通常，将其与碳复合形成硅碳材料，来缓解体积膨胀，提高导电性，提高电池的循环性能，但未有明显改善。
因此，发现一种兼顾能量密度和循环性能的电池是十分重要的。
发明内容
本公开的目的在于克服现有技术存在的上述问题，提供一种负极材料、包括该负极材料的负极片以及包括该负极材料的电池。本公开的负极材料包括具有中空结构的硅碳颗粒，该硅碳颗粒中硅的质量含量与中空结构的空腔半径占所述硅碳颗粒的半径的比值具有特定的关系，使得所述负极材料可以有效缓解硅材料在电池循环过程中的膨胀，提升电池的循环性能，并且可以有效提高负极材料的导电性。
本公开第一方面提供了一种负极材料，所述负极材料包括硅碳颗粒，所述硅碳颗粒具有中空结构，所述中空结构包括空腔和围绕所述空腔的外壳，所述外壳包括硅碳层；所述硅碳颗粒中硅的质量含量ω(单位：％)与所述空腔的半径占所述硅碳颗粒的半径的比值a(单位：％)满足
本公开第二方面提供了一种负极片，所述负极片包括本公开第一方面所述的 负极材料。
本公开第三方面提供了一种电池，所述电池包括本公开第一方面所述的负极材料和/或本公开第二方面所述的负极片。
通过上述技术方案，本公开与现有技术相比至少具有以下优势：
(1)本公开的负极材料包括具有中空结构的硅碳颗粒，该中空结构可以缓解硅的膨胀；
(2)本公开的负极材料包括硅碳颗粒，该硅碳颗粒包括外壳以及由该外壳围绕形成的空腔，所述硅碳颗粒中硅的质量含量与所述空腔的半径占所述硅碳颗粒的半径的比值具有特定的关系，能够进一步缓解硅的体积膨胀。
在本文中所披露的范围的端点和任何值都不限于该精确的范围或值，这些范围或值应当理解为包含接近这些范围或值的值。对于数值范围来说，各个范围的端点值之间、各个范围的端点值和单独的点值之间，以及单独的点值之间可以彼此组合而得到一个或多个新的数值范围，这些数值范围应被视为在本文中具体公开。
附图说明
图1所示为本公开中所述中空结构的示意图。
图2所示为本公开一实例中所述硅碳颗粒的能谱元素分布图。
图3所示为本公开一实例中所述硅碳颗粒的XRD图谱与一对比例中硅碳材料的XRD图谱的对比图。
图4所示为本公开中所述中空结构的示意图。
图5所示为本公开实施例1制备得到的硅碳颗粒的SEM镜图。
图6所示为本公开对比例1制备得到的硅碳材料的SEM镜图。
图7所示为本公开实施例1中制备得到的硅碳颗粒的能谱元素分布图的点扫结果。
图8所示为本公开实施例5中制备得到的硅碳颗粒的能谱元素分布图的点扫结果。
具体实施方式
以下对本公开的具体实施方式进行详细说明。应当理解的是，此处所描述的具体实施方式仅用于说明和解释本公开，并不用于限制本公开。
本公开第一方面提供了一种负极材料，所述负极材料可以包括硅碳颗粒，所述硅碳颗粒具有中空结构，所述中空结构可以包括空腔和围绕所述空腔的外壳。如图1所示为本公开中所述中空结构的示意图，在图1中，所述中空结构包括空腔2和围绕所述空腔2的外壳1(其中，图1中虚线标出的r1和r2分别表示空腔的半径和硅碳颗粒的半径)。
在本公开中，所述外壳可以包括硅碳层。
在一实例中，所述外壳为硅碳层。
在本公开中，所述硅碳颗粒中硅的质量含量ω(单位：％)与所述空腔的半径占所述硅碳颗粒的半径的比值a(单位：％)满足
以本公开实施例1为例对上述关系式进行说明，所述硅碳颗粒中硅的质量含量ω为13％，a为49.26％，计算得到为0.13，满足
在本公开中，所述空腔的半径占所述硅碳颗粒的半径的比值指的是，所述空腔的半径与所述硅碳颗粒的半径的比值。
常规的硅碳材料在作为负极材料使用时，会随着电池的充放电循环而膨胀和收缩，这导致了硅碳材料的逐渐失效；本公开的发明人发现，当该硅碳材料具有中空结构时，该中空结构能够缓解硅的膨胀；进一步地，当该中空结构的空腔的半径占该硅碳材料的半径的比值与该硅碳材料中硅的含量存在特定的关系时，能够进一步缓解硅的膨胀，从而显著提高电池的循环性能。
在本公开中，所述硅碳颗粒中硅的质量含量ω可以为0.01％-90％，例如0.01％、0.05％、0.1％、0.5％、1％、5％、10％、15％、20％、25％、30％、35％、40％、45％、50％、55％、60％、65％、70％、75％、80％、85％或90％。
在一实例中，所述硅碳颗粒中硅的质量含量ω为5％-20％。
本公开的发明人发现，当硅碳颗粒中硅的质量含量在特定范围内时，能够使得电池兼顾能量密度和循环性能。
在本公开中，所述硅碳颗粒中硅的质量含量ω可以通过本领域常规的方法测试得到，例如采用碳硫分析仪。
在本公开中，所述空腔的半径可以为0.05μm-14.5μm，例如0.05μm、0.1μm、0.5μm、1μm、2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm、10μm、11μm、12μm、13μm、14μm或14.5μm。
在本公开中，所述空腔的半径(r1)占所述硅碳颗粒的半径(r2)的比值a可以为0.3％-97％，例如0.3％、0.5％、1％、5％、10％、15％、20％、25％、30％、35％、40％、45％、50％、55％、60％、65％、70％、75％、80％、85％、90％、95％或97％。
在一实例中，所述空腔的半径(r1)为0.5μm-4μm。
在本公开中，所述硅碳颗粒的半径和所述空腔的半径可以通过本领域常规的方法测试得到，例如通过扫描电子显微镜(SEM)。在所述硅碳颗粒的SEM镜图的视野中，随机选取20个硅碳颗粒，使用测量工具测量硅碳颗粒的半径以及空腔的半径，取平均值。当SEM镜图中，所述硅碳颗粒和所述空腔为标准的圆形时，则硅碳颗粒的半径以及空腔的半径为该圆形的半径；当SEM镜图中，所述硅碳颗粒和所述空腔为非标准的圆形(例如椭圆形)时，则硅碳颗粒的半径以及空腔的半径为与该非标准的圆形面积相等的标准圆形的半径的等效半径。
在本公开中，所述硅碳颗粒中的碳包括多孔碳。
在本公开中，所述多孔碳的孔径可以为0.001nm-50nm，例如0.001nm、0.005nm、0.01nm、0.05nm、0.1nm、0.2nm、0.3nm、0.4nm、0.5nm、0.6nm、0.7nm、0.8nm、0.9nm、1nm、5nm、10nm、15nm、20nm、25nm、30nm、35nm、40nm、45nm或50nm。
在一实例中，所述多孔碳的孔径为0.005nm-20nm。
在一实例中，所述多孔碳的孔径为0.01nm-10nm。
本公开的发明人发现，当多孔碳的孔径在特定范围内时，对硅材料的体积膨 胀有较好的缓解作用。
在本公开中，所述多孔碳的孔径可以通过本领域常规的方法测试得到，例如参照国标GB/T 19587-2017；又例如使用设备Micromeritics TristarⅡ3020。
在一实例中，所述多孔碳包括微孔和/或介孔。
本公开的发明人发现，所述多孔碳具有丰富的微孔和/或介孔，在所述多孔碳的微孔和/或介孔中负载硅材料，不仅可以形成互联互通的导电网络，增强硅材料之间的电子连通性，而且可以减少硅材料的团聚，还可以为硅材料的体积膨胀提供缓冲空间。
在本公开中，在所述硅碳颗粒的所述硅碳层上随机选择五个点位，每个点位上硅的质量和碳的质量的比值为mn，对所述五个点位上硅的质量与碳的质量的比值取平均值为m0，满足其中，n为1、2、3、4和5；例如等于1％、5％、10％、15％、20％、25％、30％、35％、40％、45％或50％。
在一实例中，在所述硅碳颗粒的所述硅碳层上随机选择五个点位，每个点位上硅的质量和碳的质量的比值为mn，对所述五个点位上硅的质量与碳的质量的比值取平均值为m0，满足其中，n为1、2、3、4和5。
在一实例中，在所述硅碳颗粒的所述硅碳层上随机选择五个点位，每个点位上硅的质量和碳的质量的比值为mn，对所述五个点位上硅的质量与碳的质量的比值取平均值为m0，满足其中，n为1、2、3、4和5。
在本公开中，所述硅碳颗粒的所述硅碳层上，随机点位上的硅的质量与碳的质量可以通过对所述硅碳颗粒进行能谱元素分布分析测试，并对测试得到的该硅碳颗粒的能谱元素分布图进行点扫测试得到，具体地：在所述硅碳颗粒的能谱元素分布图中，找到所述硅碳层所在的位置，从上述硅碳层所在的位置中随机选择5个点位，进行点扫测试，然后对各个点位进行元素分析，可以得到每个点位上硅的质量含量和碳的质量含量，其中，所述点位的点扫面积约为直径300nm的圆 形区域。
如图7所示为本公开一实例中所述硅碳颗粒的能谱元素分布图的点扫结果，从图中可以看出，五个点位上硅的质量与碳的质量的比值在一个较小的范围内，说明所述硅碳颗粒的所述硅碳层中，硅和碳的分布较均匀。
本公开的发明人发现，在所述硅碳颗粒的所述硅碳层上随机选择五个点位，并对上述五个点位上硅的质量和碳的质量的比值取平均值，得到上述随机的五个点位中每个点位的硅的质量和碳的质量的比值与所述平均值的差值，当上述随机的五个点的差值与所述平均值的比值在一定范围内时，所述硅和所述碳的分布更加均匀，可以增强所述硅之间以及所述硅和所述碳之间的导电网络，增强所述硅碳颗粒的导电性，进而增强电池的倍率性能。
在本公开中，所述硅碳颗粒中的硅均匀地分布在所述多孔碳的孔隙中，如图2所示为本公开一实例中所述硅碳颗粒的能谱元素分布图，从图2中可以看出，所述硅和所述碳分布均匀。
在本公开中，所述硅碳颗粒的中值粒径Dv50可以为2μm-30μm，例如2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm、10μm、11μm、12μm、13μm、14μm、15μm、16μm、17μm、18μm、19μm、20μm、21μm、22μm、23μm、24μm、25μm、26μm、27μm、28μm、29μm或30μm。
在一实例中，所述硅碳颗粒的中值粒径Dv50为5μm-10μm。
在本公开中，所述硅碳颗粒的中值粒径Dv50可以通过本领域常规的方法测试得到，例如激光粒度仪。
本公开的发明人发现，当所述硅碳颗粒的中值粒径Dv50在一定范围内时，所述硅碳颗粒的动力学性能较好，与电解液的副反应较小，并且在涂布过程中也更容易操作。
在本公开中，所述硅碳层的厚度可以为0.5μm-5μm，例如0.5μm、1μm、2μm、3μm、4μm或5μm。
在本公开中，所述硅碳层的厚度与所述硅碳颗粒的半径的比值可以为 3％-98％，例如3％、5％、10％、15％、20％、25％、30％、35％、40％、45％、50％、55％、60％、65％、70％、75％、80％、85％、90％、95％或98％。
本公开的发明人发现，当硅碳层的厚度与硅碳颗粒的半径的比值在特定范围内时，能够有效缓解硅碳颗粒的膨胀。
在一实例中，所述硅碳层的厚度为1μm-4.5μm。
本公开的发明人发现，当硅碳层的厚度在特定范围内时，能够有效缓解硅碳颗粒的膨胀。
在本公开中，所述硅碳层的厚度指的是所述硅碳层单层的厚度。
在本公开中，所述硅碳层的厚度可以通过本领域常规的方法测试得到，例如SEM，在所述硅碳颗粒的SEM镜图的视野中，随机选取20个硅碳颗粒，使用测量工具测量硅碳层的厚度(每个硅碳颗粒的硅碳层随机选取至少五个点位进行测量，取平均值)，取平均值。
在本公开中，所述硅碳颗粒中的硅包括无定型硅。
本公开的发明人发现，当所述硅为无定型硅时，所述硅在电池循环过程中的体积应变更小，进而电池的循环性能更好。
在一实例中，所述硅碳颗粒中的硅为无定型硅。如图3所示为本公开一实例中所述硅碳颗粒的XRD图谱与一对比例中硅碳材料的XRD图谱的对比图，其中图3(a)为本公开一实例中所述硅碳颗粒的XRD图谱，图3(b)为本公开一对比例中硅碳材料的XRD图谱，从图中可以看出本公开所述的硅碳颗粒中的硅包括无定型硅。
在本公开中，所述硅的中值粒径Dv50可以为0.01nm-150nm，例如0.01nm、0.05nm、0.1nm、0.5nm、1nm、2nm、5nm、10nm、15nm、20nm、25nm、30nm、35nm、40nm、45nm、50nm、55nm、60nm、65nm、70nm、75nm、80nm、85nm、90nm、95nm、100nm、110nm、120nm、130nm、140nm或150nm。
在一实例中，所述硅的中值粒径Dv50为1nm-40nm。
在一实例中，所述硅的中值粒径Dv50为2nm-10nm。
本公开的发明人发现，当所述硅碳颗粒中的硅的中值粒径Dv50控制在一定范围内时，能够有效地降低所述硅的体积膨胀，进而有效改善电池的循环性能。
在本公开中，所述外壳还可以包括在所述硅碳层外表面的包覆层；如图4所示为本公开中所述中空结构示意图，在图4中，所述外壳1包括硅碳层1-2和在所述硅碳层1-2外表面的包覆层1-1(其中，图4中虚线标出的r1和r2分别表示空腔的半径和硅碳颗粒的半径)。
本公开的发明人发现，在所述硅碳层外表面设置包覆层，可以对所述硅碳层起到保护作用，进一步改善了电池的循环性能和倍率性能。
在本公开中，所述包覆层的厚度可以为20nm-300nm，例如20nm、25nm、30nm、35nm、40nm、45nm、50nm、55nm、60nm、65nm、70nm、75nm、80nm、85nm、90nm、95nm、100nm、150nm、200nm、250nm或300nm。
本公开的发明人发现，当包覆层的厚度在特定范围内时，能够提升电池的循环性能和倍率性能。
在本公开中，所述包覆层的厚度与所述硅碳颗粒的半径的比值可以为0.1％-30％，例如0.1％、0.3％、0.5％、1％、5％、10％、15％、20％、25％或30％。
本公开的发明人发现，当包覆层的厚度与硅碳颗粒的半径的比值在特定范围内时，能够提升电池的循环性能和倍率性能。
在一实例中，所述包覆层的厚度为50nm-70nm。
在本公开中，所述包覆层的厚度指的是所述包覆层单层的厚度。
在本公开中，所述包覆层的厚度可以通过本领域常规的方法测试得到，例如SEM，在所述硅碳颗粒的SEM镜图的视野中，随机选取20个硅碳颗粒，使用测量工具测量包覆层的厚度(每个硅碳颗粒的包覆层随机选取至少五个点位进行测量，取平均值)，取平均值。
在本公开中，所述包覆层可以包括碳层。
在一实例中，所述包覆层为碳层。
在本公开中，所述硅碳颗粒的电导率可以为10S/cm-500S/cm，例如10S/cm、 20S/cm、30S/cm、40S/cm、50S/cm、60S/cm、70S/cm、80S/cm、90S/cm、100S/cm、150S/cm、200S/cm、250S/cm、300S/cm、350S/cm、400S/cm、450S/cm或500S/cm。
在一实例中，所述硅碳颗粒的电导率为20S/cm-320S/cm。
在本公开中，所述硅碳颗粒的电导率可以根据GB/T 24533-2019的方法进行测试。
本公开的发明人发现，当所述硅碳颗粒的电导率在一定范围内时，能够进一步提高电池的倍率性能。
在本公开中，所述硅碳颗粒的比表面积可以为0.5m2/g-25m2/g，例如0.5m2/g、1m2/g、2m2/g、3m2/g、4m2/g、5m2/g、6m2/g、7m2/g、8m2/g、9m2/g、10m2/g、11m2/g、12m2/g、13m2/g、14m2/g、15m2/g、16m2/g、17m2/g、18m2/g、19m2/g、20m2/g、21m2/g、22m2/g、23m2/g、24m2/g或25m2/g。
在本公开中，所述硅碳颗粒的比表面积可以根据GB/T 24533-2019的方法进行测试。
本公开的发明人发现，当所述硅碳颗粒的比表面积在特定范围内时，所述电池具有较好的循环性能和倍率性能。
在本公开中，所述硅碳颗粒的真密度可以为1g/cm3-3g/cm3，例如1g/cm3、1.5g/cm3、2g/cm3、2.5g/cm3或3g/cm3。
在一实例中，所述硅碳颗粒的真密度为1.1g/cm3-2.2g/cm3。
在本公开中，所述硅碳颗粒的真密度可以根据GB/T 24533-2019的方法进行测试。
本公开的发明人发现，当所述硅碳颗粒的真密度在特定范围内时，所述电池具有较优的能量密度与循环性能。
本公开的负极活性材料包括具有中空结构的硅碳颗粒，可以有效缓解硅在电池循环过程中的膨胀，提高所述硅碳颗粒的导电性，进而提高电池的循环性能和倍率性能。
本公开还提供一种所述硅碳颗粒的制备方法，所述制备方法至少包括：在具 有中空结构的多孔碳中，气相沉积硅材料。
在本公开中，所述具有中空结构的多孔碳可以通过商购得到，也可以通过制备得到。
在一实例中，所述具有中空结构的多孔碳通过制备得到，所述制备方法至少包括：将具有中空结构的生物质多孔碳材料在惰性气氛下进行第一烧结。
在本公开中，所述具有中空结构的生物质多孔碳材料可以选用本领域常规使用的具有中空结构的生物质多孔碳材料，例如，选自花粉或淀粉。
本公开的发明人发现，生物质多孔碳材料的组成包括碳元素、氢元素和氧元素，其中，碳元素作为骨架，在生物质多孔碳材料中的质量占比较大，将所述生物质多孔碳材料在惰性气氛中烧结，可以得到高收率的导电碳材料；这种生物质多孔碳材料为中空壳状结构，并且存在丰富的微孔和介孔，将所述生物质多孔碳材料经过高温碳化后，生成的多孔碳具有负载硅粒子的较合适的比表面积。
在本公开中，所述惰性气氛可以选用本领域常规使用的惰性气氛，例如选自氮气、氩气、氦气、氖气和氪气中的至少一种。
在本公开中，所述第一烧结的温度可以为400℃-1300℃，例如400℃、500℃、600℃、700℃、800℃、900℃、1000℃、1100℃、1200℃或1300℃。所述第一烧结的时间可以为1h-24h，例如1h、2h、3h、4h、5h、6h、7h、8h、9h、10h、11h、12h、13h、14h、15h、16h、17h、18h、19h、20h、21h、22h、23h或24h。
在本公开中，所述气相沉积可以在气相沉积炉中进行，即，将所述具有中空结构的多孔碳置于第一气相沉积炉中。
在本公开中，所述气相沉积的条件可以包括：通入硅源和保护气体。
在一实例中，所述硅源包括甲硅烷、乙硅烷、二氯二氢硅、三氯氢硅和四氯化硅中的至少一种。
在本公开中，所述硅源的流量可以为0.5L/min-5L/min。
在一实例中，所述保护气体包括氮气、氩气、氦气、氖气和氪气中的至少一种。
在本公开中，所述气相沉积的温度可以为300℃-1000℃，例如300℃、400℃、500℃、600℃、700℃、800℃、900℃或1000℃。所述气相沉积的时间可以为0.25h-12h，例如0.25h、0.5h、1h、2h、3h、4h、5h、6h、7h、8h、9h、10h、11h或12h。
在本公开中，所述硅碳颗粒的制备方法还可以包括：在气相沉积硅材料后，进行导电性碳包覆。
在本公开中，所述导电性碳包覆可以包括气相沉积包覆。
所述气相沉积包覆，至少包括以下方法：将上述气相沉积硅材料后的材料置于第二气相沉积炉中，通入碳源和氮气，进行碳包覆。
在本公开中，所述碳源可以包括甲烷或乙炔。
在本公开中，所述碳包覆的温度可以为350℃-1000℃，例如350℃、400℃、500℃、600℃、700℃、800℃、900℃或1000℃。所述碳包覆的时间可以为0.5h-12h，例如0.5h、1h、2h、3h、4h、5h、6h、7h、8h、9h、10h、11h或12h。
本公开提供的所述硅碳颗粒的制备方法，工艺路线易于控制，通过气相沉积的方式，可以使得硅材料在多孔碳材料中均匀分布，通过控制气相沉积过程中硅源流量的大小以及气相沉积的时间和温度，可以进一步使得硅材料在多孔碳材料中均匀分布，并且使用生物质碳材料，处理方式简单，环境友好。
本公开第二方面提供了一种负极片，所述负极片包括本公开第一方面所述的负极材料。
所述负极片包括负极集流体和设置于所述负极集流体至少一侧表面的涂层，所述涂层包括本公开第一方面所述的负极材料。
所述涂层还可以包括常规用于涂层的添加剂，例如导电剂和粘结剂。
在一实例中，所述涂层包括所述负极材料、所述导电剂和所述粘结剂。
所述导电剂可以包括本领域常规使用的导电剂，例如所述导电剂选自SuperP、乙炔黑和科琴黑中的至少一种。
所述粘结剂可以包括本领域常规使用的粘结剂，例如所述粘结剂选自羧甲基 纤维素钠、羧甲基纤维素、聚偏氟乙烯和丁苯橡胶中的至少一种。
以所述涂层的总重量为基准，所述负极材料的含量可以为80-99重量％(例如80、81、82、83、84、85、86、87、88、89、90、91、92、93、94、95、96、97、98或99重量％)，所述导电剂的含量可以为0.5-10重量％(例如10、9、8、7、6、5、4、3、2、1或0.5重量％)，所述粘结剂的含量可以为0.5-10重量％(例如10、9、8、7、6、5、4、3、2、1或0.5重量％)。
在一实例中，以所述涂层的总重量为基准，所述负极材料的含量为95-99重量％，所述导电剂的含量为0.5-2.5重量％，所述粘结剂的含量为0.5-2.5重量％。
在一实例中，以所述涂层的总重量为基准，所述负极材料的含量为96-98重量％，所述导电剂的含量为1-2重量％，所述粘结剂的含量为1-2重量％。
本公开第三方面提供了一种电池，所述电池包括本公开第一方面所述的负极材料或本公开第二方面所述的负极片。
所述电池除负极片以外的组件(例如正极片、隔膜、电解液等)均可以为本领域常规的选择。
在一实例中，所述正极片包括正极集流体和涂覆于所述正极集流体至少一侧表面的正极活性物质层，所述正极活性物质层包括正极活性物质。
所述正极活性物质可以为本领域常规选择，例如，所述正极活性物质选自钴酸锂(LCO)、镍钴锰三元材料(NCM)、镍钴铝三元材料(NCA)、镍钴锰铝四元材料(NCMA)、磷酸铁锂(LFP)、磷酸锰锂(LMP)、磷酸钒锂(LVP)、锰酸锂(LMO)、镍酸锂、镍锰酸锂二元材料、富锂锰基和磷酸锰铁锂中的至少一种。
所述正极活性物质还可以包括掺杂和/或包覆的正极活性材料。
所述电池的组装方式均可以按照本领域常规的方式进行。
所述电池可以是液体电解液电池，半固态电池，也可以是全固态电池。
需要说明的是，本公开中“第一”、“第二”等数字表示方式仅用于区分不同的物质或使用方式，不代表顺序的区别。
以下将通过实施例对本公开进行详细描述。本公开所描述的实施例仅是本 公开一部分实施例，而不是全部的实施例。基于本公开中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本公开保护的范围。
在以下实例中，在没有特别说明的情况下，所用的材料均为商购的分析纯。
以下实施例用于说明本公开的电池。
实施例1
(1)硅碳颗粒的制备：
S1.将玉米淀粉放入液氮中冷冻，然后放入真空冷冻干燥机中冷冻干燥，其中，冷冻干燥的温度为-40℃，冷冻干燥的时间为12h，得到玉米淀粉粉末；
S2.将步骤S1得到的玉米淀粉粉末置于高温炉中，在氮气气氛下烧结4h，烧结温度为900℃，升温速率为5℃/min，得到多孔碳；
S3.将步骤S2得到的多孔碳粉碎，取0.5kg过200目筛网后置于可旋转管式炉中进行硅材料的气相沉积，转速为1r/min，通入高纯氮气，氮气的流量为3L/min，升温至550℃，升温速率为5℃/min，保证氮气流量不变，通入纯度为99.99％的甲硅烷，甲硅烷的流量为2.0L/min，通入甲硅烷的时间为1h；
S4.将步骤S3得到的材料经过喷雾造粒处理，过500目筛，然后置于CVD炉中进行碳包覆，通入高纯氮气，升温至900℃，升温速率为5℃/min，然后通入纯度为99.99％的乙炔，乙炔与氮气的流量比为1:1，通气时间为3h，再将得到的物料过500目筛和除磁处理，得到所述硅碳颗粒，其中除磁处理在电磁粉体除铁器中进行；
(2)制备负极片：
将步骤(1)所得的硅碳颗粒、导电炭黑和丁苯橡胶按照质量比为95:2:3，加入去离子水搅拌，后过200目筛网，得到固含量为45wt％的负极浆料，使用转移涂布机将上述负极浆料涂布于铜箔上，120℃烘干，辊压后得到负极片；
(3)制备正极片：
将钴酸锂、碳纳米管、乙炔黑和聚偏氟乙烯按照质量比为96:1.2:1.5:1.3加入搅拌罐中，再加入N-甲基吡咯烷酮搅拌，后过200目筛，得到固含量为75wt％的正极浆料，使用涂布机将上述正极浆料涂布于铝箔上，120℃烘干，辊压后得到正极片；
(4)制备电池：
将步骤(2)得到的负极片、步骤(3)得到的正极片和隔膜(聚乙烯膜)卷绕形成卷芯(宽度为62mm)，用铝塑膜包装，烘烤去除水分后注入电解液(1.0mol/L LiPF6，有机溶剂为碳酸乙烯酯(EC)、碳酸二乙酯(DEC)和碳酸甲乙酯(EMC)按照质量比为2:1:2混合)，热压化成后得到电池。
实施例2-6和对比例2，参照实施例1进行，所不同的是，通过改变所述硅碳颗粒制备过程的参数，来改变所述硅碳颗粒，具体如表1所示，其中本公开实施例1-6中硅的中值粒径Dv50均在2nm-10nm范围内(包括两端点值)，多孔碳的孔径均在0.01nm-10nm(包括两端点值)，硅碳颗粒中的硅为无定型硅。
表1
对比例1
对比例1参照实施例1进行，所不同的是，所述硅碳材料的制备方法不同， 具体地：将硅与石墨微片按照质量比为0.7:1混合，球磨后得到混合粉末，球磨速率为400r/min，球磨时间为2h；将上述混合粉末、葡萄糖、2,4,6-三滤三嗪和CTAB混合，其中，混合粉末与葡萄糖的质量比为1:11，混合粉末与2,4,6-三滤三嗪的质量比为20:1，混合粉末与CTAB的质量比为1300:1；振荡摇匀，超声分散后进行水热反应，填充比为60％，反应温度为220℃，反应时间为10h，得到混合悬浊液；将该混合悬浊液离心干燥后得到固体物料；将该固体物料在氩气气氛下煅烧7h，煅烧温度为750℃，得到硅碳材料，其中所述硅碳材料的Dv50为7.8μm，比表面积为3.5m2/g，真密度为1.65g/cm3。
测试例
(1)硅碳颗粒电导率测试：
将实施例制备得到的硅碳颗粒与对比例制备得到的硅碳材料进行电导率测试，将结果记于表2。
(2)SEM测试：
将实施例1制备得到的硅碳颗粒与对比例1制备得到的硅碳材料进行SEM测试，其中实施例1制备得到的硅碳颗粒的SEM镜图如图5所示，从图5中能够看出，所述硅碳颗粒具有中空结构，并且硅碳层中硅和碳的分布非常均匀；对比例1制备得到的硅碳材料的SEM镜图如图6所示，从图6中能够看出，硅和碳的分布不均匀。
(3)能谱元素分布分析测试-点扫测试
将实施例1和实施例5制备得到的硅碳颗粒进行能谱元素分布分析测试-点扫测试，测试结果如图7和图8所示，其中图7为实施例1的能谱元素分布分析测试-点扫测试结果，图8为实施例5的能谱元素分布分析测试-点扫测试结果；从图中能够看出，实施例1中，约为24.7％，实施例5中， 约为47％。
(4)比容量测试
将实施例制备得到的硅碳颗粒与对比例制备得到的硅碳材料加入导电炭黑和丁苯橡胶，其中，硅碳颗粒/硅碳材料、导电炭黑和丁苯橡胶的质量比为97:1:2，加入去离子水搅拌，后过200目筛网，得到固含量为45wt％的负极浆料，使用转移涂布机将上述负极浆料涂布于铜箔上，120℃烘干，辊压后得到负极片，进行锂半电池测试，具体测试方法如下：0.05C恒流放电至5mV，静置10min，0.025C恒流放电至5mV；0.05C恒流充电至1.5V，将测试结果记于表2。
(5)容量保持率测试
对实施例和对比例制备得到的电池在25℃测试温度下，进行1C/1C循环测试，将测试结果记于表2。
(6)能量密度测试
将实施例和对比例制备得到的电池在25℃条件下进行0.5C恒流恒压充电/0.2C放电测试电池放电容量，能量密度＝放电容量×平均电压/(厚度×宽度×高度)，将测试结果记于表2。
(7)倍率性能测试
将实施例和对对比例制备得到的电池在25±5℃条件下：
1、静置10min；
2、0.2C放电至下限电压；
3、静置10min；
4、恒温房下0.7C充电至上限电压，截止电流0.025C,
5、静置10min,
6、恒温房或恒温箱环境，以一定的倍率(放电倍率：0.2C/1C/2C/3C/4C)放电至下限电压；
7、静置10min；
步骤4～7循环直到所有倍率放电测试完成，将测试结果记于表2。
(8)膨胀率测试
将实施例与对比例制备得到的电池进行膨胀率测试，具体方法如下：
使用PPG厚度测试仪，测试首次充满电的厚度，以及在完成100T循环后充满电的厚度，膨胀率＝(100T循环后充满电的厚度-首次充满电的厚度)/首次充满电的厚度，并将结果记于表2。
表2
从表2可以看出，本公开的负极材料制备得到的电池与对比例1相比，电导率、100T容量保持率和倍率性能均有显著提高，膨胀率显著减小，本公开的负极材料所具有的中空结构显著改善了电池的循环性能和倍率性能；本公开的实施例1与对比例2相比，满足实施例1的容量保持率和 倍率性能明显提高，膨胀率明显降低。
以上详细描述了本公开的优选实施方式，但是，本公开并不限于此。在本公开的技术构思范围内，可以对本公开的技术方案进行多种简单变型，包括各个技术特征以任何其它的合适方式进行组合，这些简单变型和组合同样应当视为本公开所公开的内容，均属于本公开的保护范围。

Claims (15)

  1. 一种负极材料，其特征在于，所述负极材料包括硅碳颗粒，所述硅碳颗粒具有中空结构，所述中空结构包括空腔和围绕所述空腔的外壳，所述外壳包括硅碳层；所述硅碳颗粒中硅的质量含量ω与所述空腔的半径占所述硅碳颗粒的半径的比值a满足
  2. 根据权利要求1所述的负极材料，其中，所述硅碳颗粒中硅的质量含量ω为0.01％-90％；
    优选地，所述硅碳颗粒中硅的质量含量ω为5％-20％。
  3. 根据权利要求1或2所述的负极材料，其中，所述空腔的半径为0.05μm-14.5μm；优选为0.5μm-4μm；
    和/或，所述空腔的半径占所述硅碳颗粒的半径的比值a为0.3％-97％。
  4. 根据权利要求1-3中任一项所述的负极材料，其中，在所述硅碳颗粒的所述硅碳层上随机选择五个点位，每个点位上硅的质量和碳的质量的比值为mn，对所述五个点位上硅的质量与碳的质量的比值取平均值为m0，满足其中，n为1、2、3、4和5；
    优选地，满足
    更优选地，满足
  5. 根据权利要求1-4中任一项所述的负极材料，其中，所述硅碳颗粒中的碳包括多孔碳；
    优选地，所述多孔碳包括微孔和/或介孔。
  6. 根据权利要求5所述的负极材料，其中，所述多孔碳的孔径为0.001nm-50nm；
    优选地，所述多孔碳的孔径为0.005nm-20nm；
    更优选地，所述多孔碳的孔径为0.01nm-10nm。
  7. 根据权利要求1-6中任一项所述的负极材料，其中，所述硅碳颗粒的中值粒径Dv50为2μm-30μm；优选为5μm-10μm。
  8. 根据权利要求1-7中任一项所述的负极材料，其中，所述硅碳层的厚度为0.5μm-5μm；优选为1μm-4.5μm；
    和/或，所述硅碳层的厚度与所述硅碳颗粒的半径的比值为3％-98％。
  9. 根据权利要求1-8中任一项所述的负极材料，其中，所述硅碳颗粒中的硅包括无定型硅；
    和/或，所述硅的中值粒径Dv50为0.01nm-150nm；优选为2nm-10nm。
  10. 根据权利要求1-9中任一项所述的负极材料，其中，所述外壳还包括在所述硅碳层外表面的包覆层；
    优选地，所述包覆层包括碳层。
  11. 根据权利要求10所述的负极材料，其中，所述包覆层的厚度为20nm-300nm；
    优选地，所述包覆层的厚度与所述硅碳颗粒的半径的比值为0.1％-30％。
  12. 根据权利要求1-11中任一项所述的负极材料，其中，所述硅碳颗粒的电导率为10S/cm-500S/cm；优选为20S/cm-320S/cm。
  13. 根据权利要求1-12中任一项所述的负极材料，其中，所述硅碳颗粒的比表面积为0.5m2/g-25m2/g；
    和/或，所述硅碳颗粒的真密度为1g/cm3-3g/cm3；优选为1.1g/cm3-2.2g/cm3。
  14. 一种负极片，其特征在于，所述负极片包括权利要求1-13中任一项所述的负极材料。
  15. 一种电池，其特征在于，所述电池包括权利要求1-13中任一项所述的负极材料和/或权利要求14所述的负极片。
PCT/CN2024/078274 2023-03-04 2024-02-23 负极材料、负极片和电池 Ceased WO2024183545A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US19/274,916 US20250349830A1 (en) 2023-03-04 2025-07-21 Negative electrode material, negative electrode plate, and battery

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202310199614.6 2023-03-04
CN202310199614.6A CN116314674A (zh) 2023-03-04 2023-03-04 负极材料、负极片和电池

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US19/274,916 Continuation US20250349830A1 (en) 2023-03-04 2025-07-21 Negative electrode material, negative electrode plate, and battery

Publications (1)

Publication Number Publication Date
WO2024183545A1 true WO2024183545A1 (zh) 2024-09-12

Family

ID=86812572

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2024/078274 Ceased WO2024183545A1 (zh) 2023-03-04 2024-02-23 负极材料、负极片和电池

Country Status (3)

Country Link
US (1) US20250349830A1 (zh)
CN (1) CN116314674A (zh)
WO (1) WO2024183545A1 (zh)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116314674A (zh) * 2023-03-04 2023-06-23 珠海冠宇电池股份有限公司 负极材料、负极片和电池

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104334496A (zh) * 2013-05-16 2015-02-04 株式会社Lg化学 中空型硅类粒子及其制备方法和包括该粒子的锂二次电池用负极活性物质
CN106129411A (zh) * 2016-09-19 2016-11-16 深圳市贝特瑞新能源材料股份有限公司 一种空心硅基复合材料、制备方法及包含该复合材料的锂离子电池
CN108258230A (zh) * 2018-02-06 2018-07-06 深圳市普锐能源科技有限公司 一种锂离子电池用中空结构硅碳负极材料及其制备方法
CN108767220A (zh) * 2018-05-24 2018-11-06 桑德集团有限公司 硅碳复合材料及制备方法、电池负极材料和电池
CN116314674A (zh) * 2023-03-04 2023-06-23 珠海冠宇电池股份有限公司 负极材料、负极片和电池

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109748283A (zh) * 2019-03-07 2019-05-14 北京科技大学 一种锂离子电池用中空SiOx@C立方形复合负极材料及制备方法
CN115084491A (zh) * 2021-03-16 2022-09-20 恒大新能源技术(深圳)有限公司 硅碳复合材料及其制备方法、负极片、二次电池

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104334496A (zh) * 2013-05-16 2015-02-04 株式会社Lg化学 中空型硅类粒子及其制备方法和包括该粒子的锂二次电池用负极活性物质
CN106129411A (zh) * 2016-09-19 2016-11-16 深圳市贝特瑞新能源材料股份有限公司 一种空心硅基复合材料、制备方法及包含该复合材料的锂离子电池
CN108258230A (zh) * 2018-02-06 2018-07-06 深圳市普锐能源科技有限公司 一种锂离子电池用中空结构硅碳负极材料及其制备方法
CN108767220A (zh) * 2018-05-24 2018-11-06 桑德集团有限公司 硅碳复合材料及制备方法、电池负极材料和电池
CN116314674A (zh) * 2023-03-04 2023-06-23 珠海冠宇电池股份有限公司 负极材料、负极片和电池

Also Published As

Publication number Publication date
CN116314674A (zh) 2023-06-23
US20250349830A1 (en) 2025-11-13

Similar Documents

Publication Publication Date Title
CN113795945B (zh) 用于金属离子电池的电活性材料
CN113169308A (zh) 用于金属离子电池的电活性材料
JP7178488B2 (ja) 負極、並びに、それを含む電気化学装置及び電子装置
CN111446440B (zh) 一种氮掺杂碳包覆的中空中孔二氧化硅/钴纳米复合材料及其锂离子电池负极材料
CN105074971B (zh) 非水电解质二次电池用负极活性物质、使用该负极活性物质的非水电解质二次电池用负极、以及使用该负极的非水电解质二次电池
Medvedev et al. Comparison of conductive additives for high-power applications of Li-ion batteries
JP2024540577A (ja) 多峰性ケイ素‐炭素複合材料、それを含むアノードおよびその製造方法
WO2023208058A1 (zh) 负极极片及其制备方法、电池、及负极材料的制备方法
CN118851135A (zh) 一种均匀碳包覆磷酸铁锂的制备方法及其应用
Dawei et al. Facile conversion of micron/submicron Si particles into Si/C composites with excellent cycle performance
WO2026060957A1 (zh) 二次电池和用电装置
Zhang et al. Reducing the SiOx layer on Si/reduced graphene oxide enables fast and reversible lithium-ion storage capability for lithium-ion batteries
CN113130858A (zh) 硅基负极材料及其制备方法、电池和终端
WO2024183545A1 (zh) 负极材料、负极片和电池
JP7150797B2 (ja) 非水電解質二次電池用負極板の製造方法
Chen et al. High rate performance of the composites of Li4Ti5O12–Ketjen Black and Li4Ti5O12–Ketjen Black–multi-walled carbon nanotubes for Li-ion batteries
CN109643789B (zh) 锂离子电池的阳极
WO2024221435A1 (zh) 硅碳复合材料及其制备方法、负极极片、二次电池和用电装置
JP2026031573A (ja) シリカコーティング硫黄－炭素複合体及びこれを含むリチウム硫黄電池
CN112204779A (zh) 含有针铁矿的锂二次电池用正极和包含所述正极的锂二次电池
WO2024036430A1 (zh) 负极活性材料、负极极片、二次电池、用电装置和制备方法
Chen et al. Improved lithium storage performance of sulfur loaded by CMK-3 with a tailored hierarchical pore structure
Kurc Li4Ti5O12/TiO2-SiO2 and Li4Ti5O12/SiO2 composites as an anode material for Li-ion batteries
CN110828814B (zh) 夹层中空双壳结构的硅-碳-石墨烯电极材料及制备方法和应用
JP7203990B2 (ja) 負極材料、並びに、それを含む電気化学装置及び電子装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 24766267

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 24766267

Country of ref document: EP

Kind code of ref document: A1