WO2023124737A1 - 负极材料及其制备方法、锂离子电池 - Google Patents

负极材料及其制备方法、锂离子电池 Download PDF

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WO2023124737A1
WO2023124737A1 PCT/CN2022/135736 CN2022135736W WO2023124737A1 WO 2023124737 A1 WO2023124737 A1 WO 2023124737A1 CN 2022135736 W CN2022135736 W CN 2022135736W WO 2023124737 A1 WO2023124737 A1 WO 2023124737A1
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negative electrode
silicon
sio
electrode material
nano
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French (fr)
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车宗洲
何鹏
肖称茂
郭锷明
任建国
贺雪琴
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BTR New Material Group Co Ltd
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BTR New Material Group Co Ltd
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Priority to KR1020237030635A priority Critical patent/KR102940803B1/ko
Priority to EP22913992.8A priority patent/EP4273965A4/en
Priority to US18/546,086 priority patent/US20240047733A1/en
Priority to JP2023553930A priority patent/JP7802085B2/ja
Publication of WO2023124737A1 publication Critical patent/WO2023124737A1/zh
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • 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
    • H01M4/04—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
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • 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
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—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 application relates to the technical field of energy storage materials, and in particular to a negative electrode material, a preparation method thereof, and a lithium ion battery.
  • graphite is the most widely used anode material for lithium batteries, but due to its low theoretical capacity (372mAh/g), it is difficult to meet the demand for high energy density. Because of its high theoretical capacity (4200mAh/g), silicon material is considered to be a new generation of lithium battery anode material, and has received extensive attention and research from people in the industry.
  • silicon also has obvious disadvantages, such as: low conductivity of silicon; in addition, during the cycle of silicon, the volume expansion changes greatly, and it is prone to pulverization, the active material loses electrical contact with the current collector, and even further falls off from the current collector, eventually resulting in cycle failure. Severe attenuation of performance; in addition, the expansion causes the formed SEI film to rupture, exposing a new interface, and continuing to form a new SEI film, resulting in a thicker and thicker SEI film on the outer layer of silicon particles after cycling, which finally blocks the intercalation of lithium ions .
  • the embodiments of the present application include providing a negative electrode material, a preparation method thereof, and a lithium ion battery, which can improve the first effect and cycle performance of the negative electrode material while improving the volume expansion of the negative electrode material.
  • the embodiment of the present application provides a negative electrode material
  • the negative electrode material includes a composite material
  • the composite material includes a first skeleton intertwined with each other, a second skeleton and nano-silicon
  • the first skeleton includes Li x M y SiO 4 material
  • the second skeleton includes a carbon material
  • the Li x My SiO 4 material matrix or/and surface is distributed with the nano-silicon; wherein, in the Li x My SiO 4 material, x ,
  • the value of y conforms to the charge balance, and M includes metal elements capable of reducing silicon oxide except Li.
  • the negative electrode material further includes a coated carbon layer present on the surface of the composite material.
  • the thickness of the coated carbon layer is 5nm-80nm.
  • Li x M y SiO 4 material 2 ⁇ x ⁇ 3.4, 0.4 ⁇ y ⁇ 1.
  • M includes Mg or/and Al.
  • the particle size of nano-silicon is 5nm-200nm.
  • the carbon material includes one or a combination of soft carbon and hard carbon.
  • the specific surface area of the negative electrode material is 1m 2 /g-3m 2 /g.
  • the shape of the negative electrode material is spherical particles, and the average particle diameter D50 of the negative electrode material particles is 5 ⁇ m-30 ⁇ m.
  • the diameter of the second skeleton is 10nm-500nm.
  • the diameter of the first skeleton is 10 nm-400 nm.
  • the Li x My SiO 4 material accounts for 5%-30% by mass of the negative electrode material.
  • the mass percentage of nano-silicon in the negative electrode material is 30%-60%.
  • the carbon material accounts for 10%-65% by mass of the negative electrode material.
  • the carbon coating layer includes the carbon material.
  • the embodiment of the present application provides a negative electrode material
  • the negative electrode material includes Li x My SiO 4 material, carbon material and nano-silicon
  • the Li x My y SiO 4 material is a porous structure
  • the Li x My y SiO 4 material The pores of the Li x My SiO 4 material are filled with carbon materials, and nano-silicon is distributed in the matrix or/and surface of the Li x My SiO 4 material; wherein, in the Li x My y SiO 4 material, the values of x and y are in line with the charge balance, and M includes Li Metals other than those capable of reducing silicon oxide.
  • the negative electrode material further includes a coated carbon layer present on at least a part of the surface of the composite material.
  • the thickness of the coated carbon layer is 5nm-80nm.
  • Li x M y SiO 4 material 2 ⁇ x ⁇ 3.4, 0.4 ⁇ y ⁇ 1;
  • M includes Mg or/and Al.
  • the particle size of nano-silicon is 5nm-200nm.
  • the carbon material includes one or a combination of soft carbon and hard carbon.
  • the specific surface area of the negative electrode material is 1m 2 /g-3m 2 /g.
  • the shape of the negative electrode material is spherical particles, and the average particle diameter D50 of the negative electrode material is 5 ⁇ m-30 ⁇ m.
  • the porosity of the Li x My SiO 4 material is 30%-46%.
  • the Li x My SiO 4 material accounts for 5%-30% by mass of the negative electrode material.
  • the mass percentage of nano-silicon in the negative electrode material is 30%-60%.
  • the carbon material accounts for 10%-65% by mass of the negative electrode material.
  • the carbon coating layer includes carbon materials.
  • the embodiment of the present application provides a lithium ion battery, including the negative electrode material provided in the first aspect or the second aspect.
  • the embodiment of the present application provides a method for preparing an anode material, including:
  • Li x My SiO 4 material Forming a Li x My SiO 4 material with nano-silicon distributed in the matrix or/and on the surface and having a porous structure or a network structure; wherein, in the Li x My SiO 4 material, M includes materials other than Li that can reduce silicon oxides metal element;
  • the negative electrode material is obtained by filling the pores of the porous structure of the Li x My SiO 4 material or the voids of the network structure with carbon materials.
  • the preparation method includes:
  • Li x My SiO 4 material Mix a framework material with a network structure or a porous structure with a lithium salt, and then sinter to obtain a Li x My SiO 4 material, wherein the framework material includes nano-silicon, silicon oxide and metal M oxide loaded on the surface of nano-silicon ; and forming a carbon material in the pores or voids of the Li x My SiO 4 material to obtain the negative electrode material;
  • the framework material includes nano-silicon, silicon oxide and metal M oxide loaded on the surface of nano-silicon .
  • the step of forming a carbon material in the pores or voids of the Li x My SiO material to obtain the negative electrode material includes: combining the Li x My SiO material with an organic carbon source Mixing and calcining to carbonize the organic carbon source to form a carbon material; or forming a carbon material in the pores or voids of the Li x My SiO 4 material by chemical vapor deposition;
  • the step of mixing the framework material with network structure or porous structure, lithium salt and organic carbon source includes: mixing the framework material with network structure or porous structure with lithium salt, and then mixing with organic carbon source.
  • the preparation method of the skeleton material includes:
  • precursor 1 Mix silicon oxide and binder and then granulate to obtain precursor 1;
  • precursor 2 mixtureing precursor 1, metal M powder and molten salt, and performing a thermal reaction so that at least part of the silicon oxide is reduced to nano-silicon to obtain precursor 2;
  • Precursor 2 is acid-washed to remove part of the metal M oxide, so as to form a porous structure or a framework material with a network structure.
  • the silicon oxide and the binder are dispersed in the solution, and the precursor 1 is obtained by spray granulation. ;
  • the mass ratio of the silicon oxide to the binder is (40-100):1.
  • the mass ratios of precursor 1, molten salt and metal M powder are 1:(3-8):(0.5-1.5) in sequence.
  • the metal M powder includes one or more combinations of Mg powder, Al powder and MgAl alloy powder.
  • the framework material, soluble lithium salt and water are mixed, stirred evenly and then dried.
  • the addition of Li x My SiO 4 materials can supplement lithium to the negative electrode material to improve its first effect, and
  • the Li x My y SiO 4 material has good lithium ion and electronic conductivity, which can improve the electrical conductivity of the material;
  • the Li x My SiO 4 material with a network structure and the carbon material with a network structure are entangled with each other, and the carbon material with a network structure Basically distributed everywhere in the negative electrode material, it can make the conductivity of the negative electrode material higher; at the same time, because there is nano-silicon distributed in the matrix or/and surface of the Li x My SiO 4 material, the addition of nano-silicon can increase the capacity of the material.
  • nano-silicon Large, and the particle size of nano-silicon is small, and the distribution is relatively uniform; although nano-silicon will expand in volume during the charging and discharging process, due to the intertwined network structure of Li x My SiO 4 material and network structure
  • the role of carbon materials can limit the expansion of nano-silicon and avoid the structural collapse caused by the volume expansion of nano-silicon to a certain extent.
  • the negative electrode material can have better electrical conductivity, more stable structure, lower volume expansion, higher electrical conductivity, first effect and excellent rate performance.
  • the addition of Li x My SiO 4 materials can supplement lithium to the negative electrode material to improve its first effect, and
  • the Li x My SiO 4 material has good lithium ion and electron conductivity, which can improve the electrical conductivity of the material;
  • the carbon material is distributed in the pores of the porous Li x My SiO 4 material, which can make the conductivity of the negative electrode material higher.
  • nano-silicon is distributed in the matrix or/and surface of the Li x My SiO 4 material
  • the addition of nano-silicon can increase the capacity of the material, and the particle size of nano-silicon is small and the distribution is relatively uniform; although the nano-silicon Silicon will expand in volume during the charge and discharge process, but due to the porous structure of Li x My SiO 4 material and the carbon material in its pores, the expansion of nano-silicon can be limited, and nano-silicon can be avoided to a certain extent.
  • the volume expansion caused the collapse of the structure.
  • the negative electrode material can have better electrical conductivity, more stable structure, lower volume expansion, higher electrical conductivity, first effect and excellent rate performance.
  • Li x My SiO 4 material with porous structure or skeleton structure is formed, so that the distribution between nano-silicon and Li x My SiO 4 material is relatively uniform, and nano-silicon is located in Li x My y In the matrix or/and surface of SiO 4 material; after compounding with carbon material, the obtained negative electrode material has better conductivity, more stable structure, lower volume expansion, higher conductivity, first effect and excellent rate performance.
  • the lithium ion battery uses the negative electrode material provided by the application, which can make the battery have lower volume expansion, higher first effect and excellent rate performance.
  • Fig. 1 is the schematic cross-sectional view of the negative electrode material that the embodiment of the present application provides;
  • Fig. 2 is the process flow chart of the preparation method of the negative electrode material that the embodiment of the present application provides;
  • Fig. 3 is the scanning electron micrograph and the EDS figure of precursor five in embodiment 1;
  • Fig. 4 is the XRD figure of the negative electrode material that the application embodiment 1 provides;
  • Figure 5 is a scanning electron microscope image of the negative electrode material provided by Example 1 of the present application.
  • Icons 110 - Li x My SiO 4 material; 120 - Carbon material; 130 - Nano silicon.
  • the inventors have found that silicon can improve the capacity of the negative electrode material, but it is easy to cause volume expansion, and the oxide layer on the silicon surface will cause the first effect of the battery to decrease; carbon can improve the conductivity of the negative electrode material, but its capacity is low; Li x My SiO 4 can supplement lithium to the negative electrode material to improve the first effect, and the Li x My SiO 4 material has good lithium ion and electron conductivity, which can improve the electrical conductivity of the material. Therefore, the inventors provide a negative electrode material, which combines the three, so that the negative electrode material has lower volume expansion, higher electrical conductivity, first effect and excellent rate performance.
  • FIG. 1 is a schematic cross-sectional view of an anode material provided in an embodiment of the present application. Please refer to FIG. 1 .
  • the black part is Li x My SiO 4 material 110
  • the white part is nano-silicon 130
  • the gray part is carbon material 120 .
  • the negative electrode material includes a first skeleton and a second skeleton intertwined with each other, and nano-silicon 130, the first skeleton includes Li x My SiO 4 material 110, and the second skeleton includes a carbon material 120; wherein, Nano-silicon 130 is distributed in the matrix or/and on the surface of the Li x My SiO 4 material 110 .
  • the values of x and y conform to the charge balance, and M includes metal elements capable of reducing silicon oxide except Li.
  • the first skeleton and the second skeleton are intertwined with each other to form a composite skeleton
  • the Li x My SiO material 110 of the first skeleton is intertwined with the carbon material 120 of the second skeleton
  • the carbon material 120 of the second skeleton is intertwined with the second
  • a skeleton Li x My SiO 4 material 110 can make the structure of the negative electrode material more stable; at the same time, the carbon material 120 is basically evenly distributed in the entire negative electrode material, which can make the material more conductive.
  • Li x M y SiO 4 material 110 (M includes metal elements capable of reducing silicon oxides other than Li) can supplement lithium to the negative electrode material to improve its first effect.
  • Nano-silicon 130 is distributed in Li x M y SiO 4.
  • the material 110 matrix or/and surface can increase the capacity of the negative electrode material; although nano-silicon 130 will expand in volume during the charging and discharging process, due to the intertwined Li x My SiO 4 material 110 and
  • the role of the carbon material 120 can limit the expansion of the nano-silicon 130 and avoid structural collapse caused by the volume expansion of the nano-silicon 130 to a certain extent.
  • the negative electrode material can have better electrical conductivity, more stable structure, lower volume expansion, higher electrical conductivity, first effect and excellent rate performance.
  • Both the Li x My SiO 4 material 110 and the carbon material 120 may have a network structure. Due to the intertwined Li x My SiO 4 material 110 with a network structure and the carbon material 120 with a network structure, the expansion of the nano-silicon 130 can be better restricted, and the structure collapse caused by the volume expansion of the nano-silicon 130 can be avoided.
  • the conductivity of the negative electrode material can be improved, the structure is more stable, and it has lower volume expansion, higher conductivity, first effect and excellent rate performance.
  • the network structure here does not refer to the structure of the invisible computer network, but refers to the network structure of tangible material, which is equivalent to a solid structure.
  • a spherical material if there are no voids inside, which is consistent with the surface structure of the spherical material, it is called a solid structure; if there is a large void inside, it is called a hollow structure; if there are many voids inside, the void
  • the network structure in the present application is different from this.
  • the network structure in the present application has a three-dimensional three-dimensional structure (for example: spherical structure, cube structure, cuboid structure, and other irregular three-dimensional structures).
  • the surface has many pores (for example: similar to the three-dimensional metal foam structure, but the material is different, and the structure of the pores may be different), thus forming a network structure.
  • the network structure in this application refers to a structure in which the three-dimensional Li x My SiO 4 material 110 and the carbon material 120 have many voids inside and on the surface, so that the voids and materials of the two can intertwine with each other.
  • the voids in the network structure are not limited to uniformly distributed voids, which may have larger voids in some areas and smaller voids in some areas, and may be irregular voids.
  • Nano-silicon 130 is distributed in the matrix or/and surface of Li x My SiO 4 material 110, which means that the surface of Li x My SiO 4 material 110 is distributed with nano-silicon 130; or in the matrix of Li x My SiO 4 material 110 Nano-silicon 130 is distributed; or the surface and matrix of the Li x My SiO 4 material 110 are both distributed with nano-silicon 130 .
  • Nano-silicon 130 mainly refers to silicon materials with a particle size of nanometer scale.
  • the particle size of silicon materials with this particle size is relatively small. Under the same silicon content, nano-silicon 130 with smaller particle sizes is more likely to be evenly distributed in Li x M y SiO 4 material 110 on.
  • the present application records that the nano-silicon 130 is distributed in the matrix or/and on the surface of the Li x My SiO 4 material 110 , it does not limit that the mass of the Li x My SiO 4 material 110 is greater than that of the nano-silicon 130 .
  • the quality of the Li x My SiO 4 material 110 can be greater than the quality of the nano-silicon 130, and the quality of the nano-silicon 130 can also be greater than the quality of the Li x My SiO 4 material 110, and the quality of the Li x My SiO 4 material 110 It can also be comparable to the quality of nano-silicon 130.
  • the negative electrode material includes Li x My SiO 4 material 110, carbon material 120 and nano-silicon 130, Li x My SiO 4 material 110 is a porous structure, and in the pores of Li x My y SiO 4 material 110 Filling with carbon material 120; wherein, Li x My SiO 4 material 110 is distributed with nano-silicon 130 in the matrix or/and on the surface, the values of x and y conform to the charge balance, and M includes metals capable of reducing silicon oxides other than Li .
  • the pores of the porous Li x My SiO material 110 are filled with carbon material 120, which can make the structure of the negative electrode material more stable; at the same time, the carbon material 120 is basically evenly distributed in the entire negative electrode material, which can make the conductivity of the material more stable. powerful.
  • the addition of Li x M y SiO 4 material 110 (M includes metal elements capable of reducing silicon oxides other than Li) can supplement lithium to the negative electrode material to improve its first effect.
  • Nano-silicon 130 is distributed in Li x M y SiO 4.
  • the capacity of the negative electrode material can be increased; although the nano-silicon 130 will expand in volume during the charging and discharging process, due to the inter-filled porous structure of the Li x My SiO 4 material 110 and the porous carbon material 120 can limit the expansion of the nano-silicon 130 and avoid structural collapse caused by the volume expansion of the nano-silicon 130 to a certain extent.
  • the negative electrode material can have better electrical conductivity, more stable structure, lower volume expansion, higher electrical conductivity, first effect and excellent rate performance.
  • the porosity of the Li x My SiO 4 material 110 with a porous structure is 30%-46%, such as 30%, 32%, 35%, 40%, 43%, 46%, etc., that is, to ensure that Li x
  • the M y SiO 4 material has sufficient volume to fill the carbon material, which improves the conductivity of the composite negative electrode material, reduces the expansion rate of the composite negative electrode material, and ensures that the capacity will not be too low.
  • the carbon material 120 can also be regarded as a porous structure, and the porous structure here refers to: the Li x My SiO 4 material 110 and the carbon material 120 are basically three-dimensional structures, and there are many pores inside and/or on the surface , the channel can be partly connected or not connected so that the two materials can fill each other.
  • the pores of the porous structure are not limited to uniformly distributed pores, nor are they limited to pores with uniform pore diameters, which may be larger in some areas and smaller in some areas, and may be irregular pores.
  • the skeleton diameter of the carbon material 120 is 10nm-500nm; the skeleton diameter of the Li x My SiO 4 material 110 is 10nm-400nm; it is not limited to the carbon material 120 and Li x
  • the diameters of all the skeletons of the MySiO4 material 110 are within the above-mentioned range, and generally more than 70% of the skeletons have diameters within the above-mentioned range, and it is easy to realize the mutual filling of the LixMySiO4 material 110 and the carbon material 120 intertwined.
  • it does not limit that the diameters of the skeleton at different parts are the same, and the diameters of different parts of the skeleton of the same particle may be different.
  • the skeleton diameter of the carbon material 120 is 10nm-100nm, and the skeleton diameter of the Li x My SiO 4 material 110 is 10nm-90nm; or the skeleton diameter of the carbon material 120 is 100nm-300nm, and the Li x My SiO 4
  • the skeleton diameter of the material 110 is 90nm-200nm; or the skeleton diameter of the carbon material 120 is 300nm-500nm, and the skeleton diameter of the Li x My SiO 4 material 110 is 200nm-400nm.
  • the diameter of the skeleton can be obtained by observing with a scanning electron microscope.
  • the carbon material filled in the pores of the Li x My SiO 4 material is also distributed on the outer surface of the Li x My SiO 4 material, forming a coated carbon layer.
  • the formation of the coated carbon layer can make the conductivity of the negative electrode material better; on the other hand, it can limit the volume expansion of nano-silicon 130; on the other hand, it can also protect the internal structure, so that the entire material The structure is more stable.
  • the coated carbon layer is explained below .
  • the basic outer contour is spherical, and the diameter of the spherical outer contour is D1)
  • the diameter of the filled carbon filled in the Li x My SiO material of the porous structure is also D1
  • the filled carbon is also a porous structure, but , the basic outer contour is spherical, the diameter of the spherical outer contour is D1
  • the particle size of the negative electrode material is D2
  • the coated carbon layer refers to the spherical area where D2 is located minus the spherical area where D1 is located in Figure 1.
  • the coated carbon layer refers to the carbon layer structure coated outside the Li x My SiO 4 material 110 , which basically does not intertwine or fill with the Li x My SiO 4 material 110 .
  • the thickness of the coated carbon layer is 5nm-80nm.
  • the thickness of the coated carbon layer refers to the thickness of the outermost layer of the carbon layer substantially free of Li x My SiO 4 material 110, for example: the value of D in FIG. 1 is (D2-D1)/2.
  • the coated carbon layer of this thickness on the one hand, can make the structure of the material more stable; on the other hand, can effectively limit the volume expansion of silicon; The mass ratio of is more reasonable, so that the overall performance of the negative electrode material is better.
  • the thickness of the coated carbon layer can be 5nm-20nm; or the thickness of the coated carbon layer can be 20nm-40nm; or the thickness of the coated carbon layer can be 40nm-60nm; or the thickness of the coated carbon layer It can be 60nm-80nm. It should be noted that: as shown in Figure 1, the coated carbon layer is roughly a spherical layered structure, and the thickness of different positions of the spherical shape can be the same or different, which is not limited in the present application.
  • Li x M y SiO 4 material 110 2 ⁇ x ⁇ 3.4, 0.4 ⁇ y ⁇ 1, and the values of x and y conform to the charge balance.
  • M includes Mg or/and Al.
  • it is easy to react with silicon oxides and metal oxides to obtain Li x My SiO 4 material 110; Easy to obtain; on the other hand, its pre-lithiation effect is better, and the performance of the negative electrode material is better.
  • the Li x My SiO material 110 may be lithium magnesium silicate; or the Li x My SiO material 110 may be lithium aluminum silicate; or the Li x My SiO material 110 may be lithium magnesium silicate and lithium aluminum silicate mixture.
  • M may also include Ca or/and Zn.
  • the particle size of the nano-silicon 130 is 5nm-200nm; the nano-silicon 130 is more likely to be uniformly distributed on the Li x My SiO 4 material 110, and the nano-silicon 130 of this particle size can directly pass through the silicon
  • the oxide can be obtained by reduction, and the preparation is also more convenient.
  • the particle size of each nano-silicon 130 is not limited to be consistent.
  • the particle size of the nano-silicon 130 is basically within a range.
  • the particle distribution of silicon 130 is relatively uniform.
  • the particle size of nano-silicon 130 is 5nm-50nm; or the particle size of nano-silicon 130 is 50nm-100nm; or the particle size of nano-silicon 130 is 100nm-150nm; 200nm.
  • the carbon material 120 includes one or more combinations of hard carbon and soft carbon.
  • the negative electrode material has a specific surface area of 1 m 2 /g-3 m 2 /g.
  • the specific surface area of the negative electrode material is small, and there are basically no pores or a small amount of pores, so that the structure of the entire negative electrode material is more stable.
  • the specific surface area of the negative electrode material is 1m 2 /g, 1.5m 2 /g, 2m 2 /g, 2.5m 2 /g or 3m 2 /g.
  • the shape of the negative electrode material is spherical particles, and the average particle diameter D50 of the negative electrode material is 5 ⁇ m-30 ⁇ m.
  • the spherical particle here is not limited to a regular spherical shape, and it can be an irregular spherical particle, for example, there are a small amount of depressions on the surface, and the overall structure is an ellipsoid structure.
  • the average particle size here may refer to the average particle size of different particles, or may refer to the average particle size of the same particle in different directions, which is not limited here.
  • the negative electrode material with spherical particles has an average particle size D50 in the range of 5 ⁇ m-30 ⁇ m, which can make the size of the negative electrode material more uniform, so that its capacity retention rate is higher and its performance is better.
  • the average particle size D50 of the negative electrode material is 5 ⁇ m-10 ⁇ m; or the average particle size D50 of the negative electrode material is 10 ⁇ m-20 ⁇ m; or the average particle size D50 of the negative electrode material is 20 ⁇ m-30 ⁇ m.
  • the average particle diameter D50 of the negative electrode material of spherical particles is 5 ⁇ m, 8 ⁇ m, 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 25 ⁇ m or 30 ⁇ m.
  • the Li x My SiO 4 material 110 accounts for 5%-30% by mass of the negative electrode material
  • the nano-silicon 130 accounts for 30%-60% by mass of the negative electrode material
  • carbon The material 120 accounts for 10%-65% by mass of the negative electrode material.
  • the contents of the Li x My SiO 4 material 110 , the nano-silicon 130 and the carbon material 120 are limited within the above-mentioned ranges, which can make the composition of the negative electrode material more reasonable and improve the overall performance of the negative electrode material.
  • the Li x My SiO 4 material 110 accounts for 5%-10% by mass of the negative electrode material
  • the nano-silicon 130 accounts for 30%-40% by mass of the negative electrode material
  • the carbon material 120 The mass percentage of negative electrode material is 50%-65%.
  • the content of Li x My SiO 4 material 110 is relatively small, and the content of nano-silicon 130 and carbon material 120 is relatively large, which can effectively improve the first effect of the negative electrode material; at the same time, the addition of more carbon materials 120, It can effectively limit the expansion of the nano-silicon 130 during charging and discharging, and the performance of the negative electrode material is better.
  • the Li x My SiO 4 material 110 accounts for 10%-20% by mass of the negative electrode material
  • the nano-silicon 130 accounts for 30%-40% by mass of the negative electrode material
  • the carbon material 120 accounts for 50%-60% by mass of the negative electrode material.
  • the Li x My SiO 4 material 110 accounts for 20%-30% by mass of the negative electrode material
  • the nano-silicon 130 accounts for 40%-60% by mass of the negative electrode material
  • the carbon material 120 accounts for 10%-30% by mass of the negative electrode material.
  • the Li x My SiO 4 material 110 accounts for 5% by mass of the negative electrode material, the mass percent of nano-silicon 130 accounts for the negative electrode material is 60%, and the carbon material 120 accounts for the mass percent of the negative electrode material by 35% %; or, Li x My SiO 4 material 110 accounts for 10% by mass of the negative electrode material, nano-silicon 130 accounts for 50% by mass of the negative electrode material, and carbon material 120 accounts for the mass percent of the negative electrode material is 40%; or, Li x My SiO 4 material 110 accounts for 20% by mass of the negative electrode material, nano-silicon 130 accounts for 45% by mass of the negative electrode material, and carbon material 120 accounts for 100% by mass of the negative electrode material.
  • Li x My SiO 4 material 110 accounts for the mass percentage composition of negative electrode material is 30%
  • the mass percentage composition of nano-silicon 130 accounts for negative electrode material is 30%
  • carbon material 120 accounts for the mass percentage composition of negative electrode material The mass percentage is 40%.
  • the above-mentioned negative electrode materials can be used to prepare lithium-ion batteries, and the prepared lithium-ion batteries have low volume expansion, high first effect and excellent rate performance.
  • the lithium-ion battery can be used to provide electric energy to an electric device, and has better battery life.
  • the method comprises: forming a Li x My SiO 4 material with a porous structure or a network structure, filling the pores of the porous structure of the Li x My SiO 4 material or the voids of the network structure with a carbon material to obtain a negative electrode material, wherein M includes except A metal element other than Li that can reduce silicon oxide.
  • the distribution between nano-silicon and Li x My SiO 4 material is relatively uniform, and nano-silicon is located in Li x My y In the matrix or/and surface of SiO 4 material; after compounding with carbon material, the obtained negative electrode material has better conductivity, more stable structure, lower volume expansion, higher conductivity, first effect and excellent rate performance.
  • Figure 2 is a process flow diagram of the preparation method of the negative electrode material provided in the embodiment of the present application. Please refer to Figure 2.
  • the preparation method includes:
  • the silicon oxide and the binder are mixed and then granulated to obtain a precursor one.
  • Granulation by adding a binder can, on the one hand, make the particles more uniform; on the other hand, it is easy to form a skeleton with a porous structure or a network structure later.
  • the silicon oxide and the binder are dispersed in the solution, and the precursor 1 is obtained by spray granulation.
  • the dispersion of silicon oxide and binder can be made more uniform, so as to obtain particles with more uniform particle size.
  • the mass ratio of silicon oxide to binder is (40-100):1.
  • the content of silicon oxide is much higher than that of the binder.
  • the main component of the granulated precursor is silicon oxide, and the binder is only used as a bonding material for granulation.
  • the mass ratio of silicon oxide to binder is (40-60):1; or the mass ratio of silicon oxide to binder is (60-80):1; or the mass ratio of silicon oxide to binder is (60-80):1;
  • the mass ratio of binder is (80-100):1.
  • the mass ratio of silicon oxide to binder is 40:1, 50:1, 60:1, 70:1, 80:1, 90:1 or 100:1, etc.
  • the silicon oxide is one or more combinations of SiO, SiO 2 , Si 2 O 6 .
  • silicon oxide is silicon dioxide, which is relatively stable and has wider sources.
  • the binder is epoxy resin, phenolic resin, furfural resin, urea-formaldehyde resin, polyvinyl alcohol, polyvinyl chloride, polyethylene glycol, polyethylene oxide, polyvinylidene fluoride, glucose , sucrose, asphalt, polystyrene, polypyrrole, polyaniline, sodium carboxymethylcellulose, polyvinylpyrrolidone or one or more combinations.
  • disperse the silicon oxide in the aqueous solution stir evenly, add the binder to the solution, the mass ratio of the silicon oxide to the binder is (40-60):1, continue to stir evenly, and then spray granulate , to obtain precursor one.
  • S120 mixes precursor 1, metal M powder and molten salt, and conducts a thermal reaction so that at least part of the silicon oxide is reduced to nano-silicon to obtain precursor 2.
  • M includes metal elements capable of reducing silicon oxide other than Li.
  • the thermal reaction the silicon oxide is reduced to nano-silicon by the metal M, and the metal M is converted into a metal M oxide, and the formed particles basically have a structure in which the inner shell is nano-silicon and the surface layer is a metal M oxide, and, Molten salt is distributed between the particles.
  • the molten salt can be distributed between a part of the nano-silicon, or between a part of the nano-silicon and the nano-silicon. combined together.
  • molten salt can control the reaction of the thermal reaction and avoid the violent reaction to a certain extent; at the same time, it can also avoid the bonding or agglomeration between the particles, so that the negative electrode material with more uniform particles can be formed finally, and the reaction is also stable. Easier to control; also facilitates the formation of a porous structure after the subsequent removal of the molten salt.
  • the mass ratio of the precursor 1, the molten salt and the metal M powder is 1:(3-8):(0.5-1).
  • the content of molten salt is more, and it basically does not participate in the reaction.
  • a porous structure or network structure can be formed for the preparation of negative electrode materials; the mass ratio of precursor one to metal M powder is within the above range, so that it can be More silicon oxide is reduced, and nano-silicon is obtained.
  • the mass ratio of precursor one, molten salt and metal M powder is 1:(3-5):(0.8-1); or the mass ratio of precursor one, molten salt and metal M powder is sequentially 1:(5-8):(0.5-0.8); or the mass ratio of precursor 1, molten salt and metal M powder is 1:(3-6):(0.5-0.7).
  • the mass ratio of precursor 1, molten salt and metal M powder is 1:3:0.8, 1:4:0.8, 1:5:0.8, 1:6:0.8, 1:7:0.8, 1:8 :0.8, 1:3:0.9, 1:4:0.9, 1:5:0.9, 1:6:0.9, 1:7:0.9, 1:8:0.9, 1:3:1, 1:4:1 , 1:5:1, 1:6:1, 1:7:1 or 1:8:1, etc.
  • the metal M powder includes one or more combinations of Mg powder, Al powder and MgAl alloy powder. Due to the oxidation-reduction reaction in the process of thermal reaction, metal M powder is in contact with silicon oxide, and the formed metal M oxide is mostly formed on the surface of nano-silicon, but it is not limited to all on the surface of nano-silicon. The M oxide may also not be formed on the surface of the nano-silicon, which is not limited here.
  • the metal M powder may also include calcium powder, zinc powder, and the like.
  • the molten salt is magnesium chloride, sodium chloride, potassium chloride, calcium chloride, copper chloride, sodium sulfate, calcium sulfate, barium sulfate, aluminum sulfate, sodium nitrate, potassium nitrate, ammonium nitrate, One or more combinations of calcium nitrate, lead nitrate, cerium nitrate, sodium fluoride, potassium fluoride, calcium fluoride.
  • the thermal reaction conditions are: reacting for 1h-10h at a temperature of 400°C-800°C in an inert gas atmosphere. Reaction in an inert gas atmosphere, metal M powder will not be oxidized by oxygen substantially, but redox reaction occurs with silicon oxide, so that silicon oxide is converted into nano-silicon; the temperature and time of thermal reaction are within the above range, can Make the reduction effect of silicon oxide better.
  • the conditions of the thermal reaction are: in a nitrogen atmosphere, react at a temperature of 400°C-500°C for 8h-10h; or in a nitrogen atmosphere, react at a temperature of 500°C-600°C for 6h -8h; or, in a nitrogen atmosphere, react at a temperature of 600-700°C for 1h-6h; or, in a nitrogen atmosphere, react at a temperature of 700°C-800°C for 1h-6h.
  • the precursor one, the metal M powder and the molten salt are mixed, and the mass ratio of the precursor one, the molten salt and the metal M powder is 1:(3-8):(0.5-1.5); after mixing, place In a nitrogen atmosphere, react for 1h-10h at a temperature of 400°C-800°C to obtain the precursor 2.
  • S130 pickling the precursor 2 to remove part of the metal M oxide, so as to form the precursor 3.
  • the pickling step is carried out in an acid solution. After the precursor 2 is mixed with the acid solution, part of the metal M oxide on the surface of the nano-silicon is dissolved in the acid solution; the molten salt is dissolved in the acid solution to form a collection of nano-silicon as a porous structure or Network structure, the surface of nano-silicon may be partly attached by metal M oxide, and partly exposed.
  • the precursor three is a framework material with a network structure or a porous structure, and the framework material includes nano-silicon, silicon oxide and metal M oxide loaded on the surface of nano-silicon, wherein the silicon oxide can be unreduced silicon oxide, It can also be the silicon oxide formed naturally on the surface after the nano-silicon is exposed.
  • the acid solution is one or more combinations of nitric acid solution, hydrochloric acid solution and sulfuric acid solution.
  • the mass concentration of the nitric acid solution is 5%-15%
  • the mass concentration of the hydrochloric acid solution is 5%-15%
  • the mass concentration of the sulfuric acid solution is 5%-15%
  • the acid solution is added in an amount of 10%-120% of the mass of the precursor.
  • the amount of the acid solution added is 10%-30% of the mass of the precursor; or, the amount of the acid solution added is 30%-50% of the mass of the precursor; or, the amount of the acid solution added is the amount of the precursor 50%-80% of the mass of the precursor 2; or, the added amount of the acid solution is 80%-120% of the mass of the precursor 2.
  • the amount of acid solution added is 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 110% or 120% of the mass of the precursor.
  • the precursor 2 is mixed with hydrochloric acid solution with a mass concentration of 5%-15% and immersed for 0.3h-1h.
  • hydrochloric acid solution with a mass concentration of 5%-15% and immersed for 0.3h-1h.
  • part of the metal oxide can be removed, and then washed with water Impurities are removed after solid-liquid separation (the method of solid-liquid separation can be centrifugation, filtration, suction filtration, etc.), and then dried to obtain a porous structure or network structure skeleton material.
  • the skeleton material includes nano-silicon, silicon oxide loaded on the surface of nano-silicon substances and metal M oxides.
  • step S110-step S130 may or may not be implemented, and the skeleton material with porous structure or network structure may also be obtained by using other methods.
  • the precursor 3 is mixed with a lithium salt and fired to obtain a Li x My SiO 4 material with a porous structure or a network structure.
  • nano-silicon is distributed in the matrix or/and surface of the Li x My SiO 4 material, and the values of x and y conform to the charge balance.
  • Using a certain concentration of acid solution to soak the precursor 2 for a certain period of time can remove part of the metal M oxide in the precursor 2, and more nano-silicon is exposed to form a porous structure (skeleton of a porous structure or a network structure) ); after the lithium salt is mixed with the precursor three, the lithium salt will be mixed with nano-silicon, metal M oxide and silicon oxide (this silicon oxide can be unreduced silicon oxide, or after nano-silicon is exposed Silicon oxide formed naturally on the surface.)
  • Contact, when firing, part of silicon oxide, metal M oxide and lithium salt react to obtain porous structure or network structure Li x My SiO 4 material; at this time, Nano-silicon is distributed in the matrix or/and on the surface of the Li x My SiO 4 material.
  • the lithium salt is one or more combinations of lithium acetate, lithium oxalate, lithium carbonate, lithium hydroxide, lithium formate, lithium benzoate, lithium chloride, lithium sulfate, and lithium nitrate.
  • the firing conditions are: firing for 1h-10h in an inert gas atmosphere at a temperature of 600°C-1200°C.
  • the firing conditions are: in a nitrogen atmosphere, react at a temperature of 600°C-800°C for 8h-10h; or in a nitrogen atmosphere, react at a temperature of 800°C-1000°C for 5h -8h; or, in a nitrogen atmosphere, react at a temperature of 1000°C-1200°C for 1h-5h.
  • the precursor three, soluble lithium salt and water are mixed, stirred uniformly and then dried; in an inert gas atmosphere, fired at a temperature of 600°C-1200°C for 1h-10h to obtain a Li x My SiO 4 material.
  • soluble lithium salt to mix with precursor 3 in water can make the surface of precursor 3 evenly adsorb a layer of soluble lithium salt. After drying, the lithium salt is adsorbed on the surface of precursor 3, which is convenient to control during subsequent firing.
  • the amount of Li x My SiO 4 material, and the nano-silicon can be uniformly distributed on the Li x My SiO 4 material.
  • Li x My SiO 4 material is a porous structure or a network structure, and there are nano-silicon distributed in the Li x My y SiO 4 material matrix or/and on the surface, there are many pores inside the Li x My y SiO 4 material, and the carbon material is formed in the In the pores of the Li x My SiO 4 material, the Li x My SiO 4 material is filled or entangled with each other to obtain a negative electrode material. And if the mass of the carbon material is more, a coated carbon layer can also be formed on the surface, and a negative electrode material with better performance can be obtained.
  • the Li x My SiO 4 material is mixed with an organic carbon source and calcined to carbonize the organic carbon source to form a carbon material.
  • a part of the organic carbon source will enter the pores of the Li x My SiO 4 material, and a part of the organic carbon source will be coated on the surface of the Li x My SiO 4 material, During calcination, a carbon material interfilled with the Li x My SiO 4 material can be formed, and a coated carbon layer can be formed on the surface.
  • the organic carbon source is one or more combinations of polymers, sugars, organic acids, asphalt and polymer materials; for example: the organic carbon source is polyvinyl chloride, polyvinyl butyral, sucrose, glucose, Citric acid, asphalt, furfural resin, epoxy resin, phenolic resin, polyacrylic acid, etc.
  • the mixing method of the Li x My SiO 4 material and the organic carbon source can be hot-press coated, and the Li x My SiO 4 material and the organic carbon source are mixed uniformly and then placed in a firing furnace.
  • a firing furnace In an inert gas atmosphere, under the pressure of 5Mpa-20Mpa and the temperature of 700°C-1200°C, calcining for 1h-10h to carbonize the organic carbon source.
  • the organic carbon source can be hot-pressed into the pores or voids of the porous structure Li x My SiO 4 material, so that after the subsequent carbonization of the organic carbon source, the porous structure of the Li x My SiO 4 The pores or voids of the material are filled with carbon materials.
  • the conditions for carbonizing the organic carbon source are: in a nitrogen atmosphere, react at a temperature of 700°C-800°C for 8h-10h; or, in a nitrogen atmosphere, at a temperature of 800°C-1000°C React for 5h-8h; or, react for 1h-5h at a temperature of 1000°C-1200°C in a nitrogen atmosphere.
  • the pressure of the hot press sintering furnace is 5Mpa-20Mpa, and the pressure is relatively high. Since the volume of the organic carbon source will decrease after the carbonization of the organic carbon source during the calcination process, the carbon material can be hot-pressed to the porous structure of Li x M while calcining. y SiO 4 material, so that the entanglement between the carbon material with a porous structure and the Li x My y SiO 4 material with a porous structure is tighter, the filling is tighter, and the performance of the negative electrode material is better.
  • the conditions for carbonizing the organic carbon source are: react in an inert gas atmosphere with a pressure of 5Mpa-10Mpa and a temperature of 700°C-800°C for 8h-10h; or, at a pressure of 10Mpa-15Mpa and a temperature of 800°C React in an inert gas atmosphere at -1000°C for 5h-8h; or, react in an inert gas atmosphere at a pressure of 15Mpa-20Mpa and a temperature of 1000°C-1200°C for 1h-5h.
  • the Li x My SiO 4 material is placed in a chemical vapor deposition furnace, and carbon materials are formed in the channels and surfaces of the Li x My SiO 4 material by chemical vapor deposition.
  • the carbon material is formed by chemical vapor deposition and filled in the pores of the Li x My SiO 4 material, and the filling effect is good. Even if the pores are small, it can enter the Li x My SiO 4 material with a porous structure through the gas source. Inside, a carbon material with a porous structure and a Li x My SiO 4 material with a porous structure are formed that are entangled with each other.
  • the conditions of the chemical vapor deposition method are: using acetylene, methane or acetone as the carbon source, using argon or nitrogen as the protective gas, and vapor deposition at 750°C-1200°C.
  • step S140 and step S150 are performed twice through sintering and calcination respectively, but this application does not limit it to be performed twice, and it can also be prepared through one heat treatment.
  • the precursor 3 is mixed with the lithium salt and the organic carbon source, and then heat-treated to obtain the negative electrode material, wherein the precursor 3 is a skeleton material with a porous structure or a network structure, and the skeleton material includes nano-silicon, silicon on the surface of the nano-silicon oxides and metal oxides.
  • part of the nano-silicon, silicon oxide, metal oxide and lithium salt can be reacted to obtain a Li x My SiO 4 material with a porous structure or a network structure; at the same time, the organic carbon source can be carbonized, The carbonized carbon material and the Li x My SiO 4 material are filled or entangled with each other.
  • the precursor 3 is mixed with a lithium salt, then mixed with an organic carbon source and then subjected to heat treatment to obtain the negative electrode material.
  • a lithium salt for example: Precursor 3, soluble lithium salt and water are mixed, stirred evenly and then dried; then the organic carbon source is coated on the surface and inside, and heat-treated for 1 hour at a temperature of 700°C-1200°C in an inert gas atmosphere -10h, the organic carbon source is carbonized to form a carbon material, and at the same time, the lithium salt is reacted to obtain a Li x My SiO 4 material.
  • the negative electrode material prepared by the above method includes intertwined or intertwined Li x My SiO 4 materials and carbon materials, and Li x My SiO 4 materials are distributed with nano-silicon in the matrix or/and on the surface, which can make The structure of the negative electrode material is more stable, and it has lower volume expansion, higher conductivity, first effect and excellent rate performance.
  • a preparation method of negative electrode material comprising the steps of:
  • the ratio of the precursor 2 to water is 1:4, after stirring evenly, add an industrial hydrochloric acid solution with a weight ratio of 1:1 to the precursor 2, react for 0.5h and then centrifuge , washed with water to remove impurities to obtain the precursor three.
  • the precursor is three-dispersed in an aqueous solution, the ratio of the framework material to water is 1:5, lithium carbonate is added to it with a weight ratio of 10:1 to the framework material, and the solvent is evaporated to dryness under stirring conditions to obtain the precursor Four.
  • Precursor 4 was placed in a rotary furnace, and fired at 1100°C for 3 hours under inert gas conditions to obtain precursor 5.
  • Fig. 3 is the scanning electron microscope picture (left figure in Fig. 3) and the EDS figure (right figure in Fig. 3) of precursor five in embodiment 1, as can be seen from Fig. 3, precursor five is porous structure, and it contains silicon Lithium magnesium silicate material and nano-silicon, and the nano-silicon is uniformly dispersed in the lithium magnesium silicate matrix.
  • Figure 4 is the XRD pattern of the negative electrode material provided by Example 1. It can be seen from Figure 4 that the negative electrode material provided by Example 1 contains Li x Mg y SiO 4 material, carbon material and nano-silicon.
  • FIG. 5 is a scanning electron microscope image of the negative electrode material provided in Example 1. It can be seen from FIG. 5 that the negative electrode material is relatively uniform and has a carbon coating layer on its surface.
  • the negative electrode material obtained in this embodiment includes a first skeleton, a second skeleton and nano silicon intertwined with each other, the first skeleton is a magnesium lithium silicate material with a network structure, and the second skeleton is a magnesium lithium silicate material with a network structure.
  • the skeleton is a carbon material with a network structure; wherein, nano-silicon is distributed in the matrix and on the surface of the lithium magnesium silicate material.
  • the negative electrode material obtained in this embodiment includes lithium magnesium silicate material, carbon material and nano-silicon.
  • the lithium magnesium silicate material has a porous structure, and the pores of the lithium magnesium silicate material are filled with Carbon material; wherein, nano-silicon is distributed in the matrix and on the surface of the lithium magnesium silicate material.
  • step (5) and step (6) are combined as follows: after mixing the precursor IV with pitch, place it in a hot-press firing furnace, Heat treatment at 800° C. for 3 hours under pressure, crush and sieve the material after heat treatment to obtain negative electrode material.
  • the negative electrode material obtained in this embodiment includes a first skeleton, a second skeleton and nano-silicon intertwined with each other, the first skeleton is a magnesium lithium silicate material with a network structure, and the second skeleton is a carbon material with a network structure; wherein, Nano-silicon is distributed in the matrix and on the surface of the lithium magnesium silicate material.
  • the negative electrode material obtained in this embodiment includes lithium magnesium silicate material, carbon material and nano-silicon.
  • the lithium magnesium silicate material has a porous structure, and the pores of the lithium magnesium silicate material are filled with carbon materials; Nano-silicon is distributed in the matrix and on the surface.
  • step (6) after mixing the precursor 5 and pitch, place it in a sintering furnace, and calcine it at 800°C for 3 hours, and the calcined material Grinding and sieving to obtain the negative electrode material.
  • the negative electrode material obtained in this embodiment includes a first skeleton, a second skeleton and nano-silicon intertwined with each other, the first skeleton is a magnesium lithium silicate material with a network structure, and the second skeleton is a carbon material with a network structure; wherein, Nano-silicon is distributed in the matrix and on the surface of the lithium magnesium silicate material.
  • the negative electrode material obtained in this embodiment includes lithium magnesium silicate material, carbon material and nano-silicon.
  • the lithium magnesium silicate material has a porous structure, and the pores of the lithium magnesium silicate material are filled with carbon materials; Nano-silicon is distributed in the matrix and on the surface.
  • step (6) the precursor 5 is placed in a chemical vapor deposition furnace, methane is introduced, deposited at 800 ° C for 3 hours, and the deposited material is pulverized and sieving to obtain the negative electrode material.
  • the carbon material can also be formed in the pores or voids of the lithium magnesium silicate material by chemical vapor deposition.
  • the negative electrode material obtained in this embodiment includes a first skeleton, a second skeleton and nano-silicon intertwined with each other, the first skeleton is a magnesium lithium silicate material with a network structure, and the second skeleton is a carbon material with a network structure; wherein, Nano-silicon is distributed in the matrix and on the surface of the lithium magnesium silicate material.
  • the negative electrode material obtained in this embodiment includes lithium magnesium silicate material, carbon material and nano-silicon.
  • the lithium magnesium silicate material has a porous structure, and the pores of the lithium magnesium silicate material are filled with carbon materials; Nano-silicon is distributed in the matrix and on the surface.
  • step (2) precursor 1 is mixed with sodium chloride, aluminum powder, the quality of mixing ratio precursor 1, sodium chloride and aluminum powder The ratio is 1:5:0.9 in turn, after mixing evenly, place in a nitrogen atmosphere at 700°C for 5 hours to obtain the precursor 2.
  • the method uses aluminum powder to reduce silicon dioxide, and finally forms lithium aluminum silicate material.
  • the negative electrode material obtained in this embodiment includes a first skeleton, a second skeleton and nano-silicon intertwined with each other, the first skeleton is a lithium aluminum silicate material with a network structure, and the second skeleton is a carbon material with a network structure; wherein, Nano-silicon is distributed in the matrix and on the surface of the lithium aluminum silicate material.
  • the negative electrode material obtained in this embodiment includes lithium aluminum silicate material, carbon material and nano-silicon, the lithium magnesium silicate material has a porous structure, and the pores of the lithium aluminum silicate material are filled with carbon materials; wherein the lithium magnesium silicate material Nano-silicon is distributed in the matrix and on the surface.
  • step (2) the precursor one is mixed with sodium chloride, magnesium powder, and aluminum powder, and the mixing ratio of precursor one, sodium chloride, and magnesium
  • the mass ratio of aluminum powder and aluminum powder is 1:5:0.45:0.4 in sequence, and after mixing evenly, place it in a nitrogen atmosphere at 700°C for 5 hours to obtain precursor 2.
  • the method uses aluminum powder and magnesium powder to simultaneously reduce silicon dioxide, and finally forms lithium aluminum silicate materials and lithium magnesium silicate materials.
  • the negative electrode material obtained in this embodiment includes a first skeleton, a second skeleton and nano-silicon intertwined with each other, the first skeleton is a mixed material of lithium aluminum silicate and lithium magnesium silicate with a network structure, and the second skeleton is a network structure.
  • the negative electrode material obtained in this embodiment includes a mixed material of lithium aluminum silicate and lithium magnesium silicate, carbon material and nano-silicon, the mixed material of lithium magnesium silicate and lithium magnesium silicate has a porous structure, and the lithium aluminum silicate material The pores are filled with carbon materials; wherein, nano-silicon is distributed in the matrix and surface of the mixed material of lithium magnesium silicate and lithium magnesium silicate.
  • Embodiment 7 The method steps of this embodiment and embodiment 1 are basically the same, and its difference is:
  • step (3) the precursor 2 is placed in the aqueous solution, the ratio of the precursor 2 to water is 1:4, after stirring evenly, an industrial hydrochloric acid solution with a weight ratio of 10:8 to the precursor 2 is added therein, and the reaction is 0.5h After centrifugation, impurities were removed by washing with water to obtain precursor 3.
  • Step (4) The precursor is three-dispersed in the aqueous solution, the ratio of the skeleton material to water is 1:5, lithium carbonate is added to it with a weight ratio of 8:1 to the skeleton material, and the solvent is evaporated to dryness under stirring conditions to obtain the precursor body four.
  • the negative electrode material obtained in this embodiment includes a first skeleton, a second skeleton and nano-silicon intertwined with each other, the first skeleton is a magnesium lithium silicate material with a network structure, and the second skeleton is a carbon material with a network structure; wherein, Nano-silicon is distributed in the matrix and on the surface of the lithium magnesium silicate material.
  • the negative electrode material obtained in this embodiment includes lithium magnesium silicate material, carbon material and nano-silicon.
  • the lithium magnesium silicate material has a porous structure, and the pores of the lithium magnesium silicate material are filled with carbon materials; Nano-silicon is distributed in the matrix and on the surface.
  • step (1) get the nano-silicon dioxide of 500g, be dispersed in the aqueous solution of 10Kg, stir the carboxymethyl cellulose wherein adding 40g sodium, stirred evenly, and then sprayed and granulated to obtain the precursor one.
  • step (6) the precursor 5 was placed in a chemical vapor deposition furnace, fed with methane, deposited at 800° C. for 5 hours, and the deposited material was pulverized and sieved to obtain the negative electrode material.
  • the negative electrode material obtained in this embodiment includes a first skeleton, a second skeleton and nano-silicon intertwined with each other, the first skeleton is a magnesium lithium silicate material with a network structure, and the second skeleton is a carbon material with a network structure; wherein, Nano-silicon is distributed in the matrix and on the surface of the lithium magnesium silicate material.
  • the negative electrode material obtained in this embodiment includes lithium magnesium silicate material, carbon material and nano-silicon.
  • the lithium magnesium silicate material has a porous structure, and the pores of the lithium magnesium silicate material are filled with carbon materials; Nano-silicon is distributed in the matrix and on the surface.
  • the method steps of this example are basically the same as those of Example 1, the difference being that: (6) After mixing the precursor 5 with pitch, place it in a hot-pressed firing furnace, and calcinate it at 800°C for 3 hours under a pressure of 30 MPa, and the calcined The material is crushed and sieved to obtain the negative electrode material.
  • the negative electrode material obtained in this embodiment includes a first skeleton, a second skeleton and nano-silicon intertwined with each other, the first skeleton is a magnesium lithium silicate material with a network structure, and the second skeleton is a carbon material with a network structure; wherein, Nano-silicon is distributed in the matrix and on the surface of the lithium magnesium silicate material.
  • the negative electrode material obtained in this embodiment includes lithium magnesium silicate material, carbon material and nano-silicon.
  • the lithium magnesium silicate material has a porous structure, and the pores of the lithium magnesium silicate material are filled with carbon materials; Nano-silicon is distributed in the matrix and on the surface.
  • the method steps of this example are basically the same as those of Example 1, the difference being: (6) After mixing the precursor 5 with pitch, place it in a hot-pressed sintering furnace, and calcinate at 800°C for 3 hours under normal pressure, and the calcined The material is crushed and sieved to obtain the negative electrode material.
  • the negative electrode material obtained in this embodiment includes a first skeleton, a second skeleton and nano-silicon intertwined with each other, the first skeleton is a magnesium lithium silicate material with a network structure, and the second skeleton is a carbon material with a network structure; wherein, Nano-silicon is distributed in the matrix and on the surface of the lithium magnesium silicate material.
  • the negative electrode material obtained in this embodiment includes lithium magnesium silicate material, carbon material and nano-silicon.
  • the lithium magnesium silicate material has a porous structure, and the pores of the lithium magnesium silicate material are filled with carbon materials; Nano-silicon is distributed in the matrix and on the surface.
  • the sum of the mass percentage of Li x My SiO 4 material, the mass percentage of nano-silicon and the mass percentage of carbon material is close to and less than 100%.
  • the test method of the thickness of the coated carbon layer is: section SEM test;
  • test method of the specific surface area of the negative electrode material is: Macbee surface analyzer;
  • test method of D50 of the negative electrode material is: Malvern laser particle size analyzer 3000;
  • the test method of the mass percentage of Li x M y SiO 4 material is: total dissolved component analysis method
  • test method for the mass percentage of nano-silicon is: X-ray fluorescence analysis method
  • the test method for the mass percentage of carbon materials is: infrared carbon and sulfur analyzer;
  • the testing method of porosity is: the porosity is measured by mercury intrusion porosimetry. The porosity is measured at least three times, and the arithmetic mean of at least three times is used as the measurement result;
  • the test method for the distribution range of the skeleton diameter the skeleton diameter is measured at different points in the fixed area by scanning electron microscope, and the distribution range of the skeleton diameter is obtained.
  • step (4) is not carried out, and finally no lithium magnesium silicate material is formed.
  • step (4) and step (6) are not carried out, and finally no lithium magnesium silicate material and carbon material are formed.
  • the method step of this comparative example is basically the same as that of Example 1, and the difference is that in step (2), no molten sodium chloride is added, and no porous structure or network structure is formed.
  • step (3) hydrochloric acid cleaning reaction is not carried out, and no porous magnesium lithium silicate material is formed.
  • Table 2 shows the properties of the negative electrode materials provided in Example 1-Example 6 and Comparative Example 1-Comparative Example 4.
  • the negative electrode material provided by the embodiment of the present application has a high first effect, a high cycle retention rate, and a small volume expansion coefficient.
  • Example 1 From the comparison of Example 1 and Comparative Example 2, it can be seen that in Comparative Example 2, no lithium carbonate was added to prepare the magnesium lithium silicate material, and carbon coating was not carried out. Although the obtained negative electrode material has a high capacity, its volume expansion The coefficient is very high, and the cycle retention rate is very small, and the first effect is also low.
  • Comparing Example 1 and Comparative Example 4 it can be seen that in Comparative Example 4, molten salt was added but not pickled with hydrochloric acid, and the obtained negative electrode material contained more molten salt, and it was not easy to form porous magnesium lithium silicate.
  • the material has low capacity, first effect and cycle retention, and high coefficient of volume expansion.
  • Example 1 Comparing Example 1 and Example 2, it can be seen that in Example 1, the lithium magnesium silicate material is obtained by firing first, and then the carbon material is obtained by calcining; in Example 2, lithium magnesium silicate and carbon material are formed by one heat treatment to obtain There is little difference in the properties of the negative electrode materials, which means that the performance of the obtained negative electrode materials can be made better by sintering, calcination, or one-time heat treatment.
  • Example 1 is pressure coating
  • Example 3 is normal pressure coating
  • the performance of the negative electrode material obtained by pressure coating is relatively better.
  • Example 1 Comparing Example 1 and Example 4, it can be seen that in Example 1, the carbon material was prepared by coating with pitch, and in Example 4, the carbon material was prepared by chemical vapor deposition, and the performance of the obtained negative electrode material quite.
  • Embodiment 1, embodiment 5 and embodiment 6 contrast and can find out, the M metal in the Li x My SiO in the embodiment 1 is magnesium, the M metal in the embodiment 5 is aluminum, and the M metal in the embodiment 6
  • the M metal is a mixture of magnesium and aluminum, and the performance of the final negative electrode material is comparable.
  • Example 7 Comparing Example 1, Example 7 and Example 8, it can be seen that the diameter of the first skeleton in the negative electrode material of Example 7 is too large, the gram capacity and first effect of the material are reduced, and the cycle performance and expansion performance are not significantly improved. It is because the size of the first skeleton is relatively large, which makes it difficult for lithium ions to deintercalate in the nano-silicon particles, resulting in a decrease in the capacity and first effect of the material. In the negative electrode material of Example 8, the diameter of the second skeleton is too large, and the electrical performance decreases. This is because the diameter of the second skeleton increases, the carbon content in the material increases, and the capacity and first effect of the carbon material are lower than those of nano-silicon, resulting in a decrease in the capacity and first effect of the composite material.
  • Example 9 Comparing Example 1, Example 9 and Example 10, it can be seen that the porosity of the negative electrode material in Example 9 is too small, and the expansion of the material becomes larger. The space for expansion is relatively reduced, resulting in greater cycle expansion of the material. The porosity of Example 10 is too large, the specific surface area of the material becomes larger, and the cycle performance deteriorates. This is because the gap increases and the electrolyte solution penetrates into the material more easily. , leading to an increase in the side reaction between nano-silicon and electrolyte, and poor cycle performance.

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Abstract

本申请涉及一种负极材料及其制备方法、锂离子电池，属于储能材料技术领域。该负极材料包括Li xM ySiO 4材料、碳材料以及纳米硅，所述Li xM ySiO 4材料和所述碳材料均呈网络结构，其在所述负极材料中各自独立地形成第一骨架和第二骨架，所述第一骨架和所述第二骨架相互交缠，所述Li xM ySiO 4材料基质内或/和表面分布有所述纳米硅；其中，所述Li xM ySiO 4材料中，x、y的取值符合电荷平衡，M包括除Li以外的能够还原硅氧化物的金属元素。该负极材料的导电性较佳，结构更加稳定，并具有较低的体积膨胀、较高的导电性、首效以及优异的倍率性能。

Description

负极材料及其制备方法、锂离子电池
本申请要求于2021年12月31日提交中国专利局、申请号为2021116652522、申请名称为“负极材料及其制备方法、锂离子电池”的中国专利的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及储能材料技术领域，且特别涉及一种负极材料及其制备方法、锂离子电池。
背景技术
目前锂电池负极材料应用最广泛的石墨材料，但由于其理论容量偏低(372mAh/g)，难以满足高能量密度的需求。硅材料因其具有较高的理论容量(4200mAh/g)，被认为是新一代锂电池负极材料，受到了行业内人员的广泛关注与研究。
但是硅也有很明显的缺点，比如：硅电导率低；此外，硅循环过程中体积膨胀变化巨大，易发生粉化、活性物质与集流体失去电接触，甚至进一步从集流体脱落，最终造成循环性能的严重衰减；另外，膨胀导致形成的SEI膜破裂，暴露出新的界面，继续形成新的SEI膜，导致循环之后硅颗粒外层的SEI膜越来越厚，最终阻隔了锂离子的嵌入。
如何更加有效缓解硅体积膨胀，保证硅负极循环稳定性，获得较低体积膨胀、较高首效、长循环寿命的硅负极材料，是当前锂电池领域亟待解决的技术热点。
将石墨和硅复合可以在一定程度上解决上述问题，但是，现有硅碳复 合材料通常是碳层内包覆硅，降低了硅碳复合材料的首效。
发明内容
本申请实施例包括提供一种负极材料及其制备方法、锂离子电池，能够在改善负极材料的体积膨胀的同时，提高其首效和循环性能。
第一方面，本申请实施例提供了一种负极材料，负极材料包括复合材料，所述复合材料包括相互交缠的第一骨架、第二骨架及纳米硅，所述第一骨架包括Li xM ySiO 4材料，所述第二骨架包括碳材料，所述Li xM ySiO 4材料基质内或/和表面分布有所述纳米硅；其中，所述Li xM ySiO 4材料中，x、y的取值符合电荷平衡，M包括除Li以外的能够还原硅氧化物的金属元素。
结合第一方面，本申请的部分实施例中，负极材料还包括存在于复合材料表面的包覆碳层。
结合第一方面，本申请的部分实施例中，包覆碳层的厚度为5nm-80nm。
结合第一方面，本申请的部分实施例中，
Li xM ySiO 4材料中，2≤x≤3.4，0.4≤y≤1。
结合第一方面，本申请的部分实施例中，M包括Mg或/和Al。
结合第一方面，本申请的部分实施例中，纳米硅的粒径为5nm-200nm。
结合第一方面，本申请的部分实施例中，碳材料包括软碳和硬碳中的一种或两种组合。
结合第一方面，本申请的部分实施例中，负极材料的比表面积为1m 2/g-3m 2/g。
结合第一方面，本申请的部分实施例中，负极材料的形状为球状颗粒，负极材料的颗粒平均粒径D50为5μm-30μm。
结合第一方面，本申请的部分实施例中，第二骨架的直径为10nm-500nm。
结合第一方面，本申请的部分实施例中，第一骨架的直径为10nm-400nm。
结合第一方面，本申请的部分实施例中，Li xM ySiO 4材料占负极材料的质量百分含量为5％-30％。
结合第一方面，本申请的部分实施例中，纳米硅占负极材料的质量百分含量为30％-60％。
结合第一方面，本申请的部分实施例中，碳材料占负极材料的质量百分含量为10％-65％。
结合第一方面，本申请的部分实施例中，包覆碳层包括所述碳材料。
第二方面，本申请实施例提供了一种负极材料，负极材料包括Li xM ySiO 4材料、碳材料和纳米硅，Li xM ySiO 4材料为多孔结构，Li xM ySiO 4材料的孔道内填充碳材料，Li xM ySiO 4材料基质内或/和表面分布有纳米硅；其中，Li xM ySiO 4材料中，x、y的取值符合电荷平衡，M包括除Li以外的能够还原硅氧化物的金属。
结合第二方面，本申请的部分实施例中，负极材料还包括存在于所述复合材料至少一部分表面的包覆碳层。
结合第二方面，本申请的部分实施例中，包覆碳层的厚度为5nm-80nm。
结合第二方面，本申请的部分实施例中，
Li xM ySiO 4材料中，2≤x≤3.4，0.4≤y≤1；
结合第二方面，本申请的部分实施例中，M包括Mg或/和Al。
结合第二方面，本申请的部分实施例中，纳米硅的粒径为5nm-200nm。
结合第二方面，本申请的部分实施例中，碳材料包括软碳和硬碳中的一种或两种组合。
结合第二方面，本申请的部分实施例中，负极材料的比表面积为1m 2/g-3m 2/g。
结合第二方面，本申请的部分实施例中，负极材料的形状为球状颗粒，负极材料的颗粒平均粒径D50为5μm-30μm。
结合第二方面，本申请的部分实施例中，Li xM ySiO 4材料的孔隙率为30％-46％。
结合第二方面，本申请的部分实施例中，Li xM ySiO 4材料占负极材料的质量百分含量为5％-30％。
结合第二方面，本申请的部分实施例中，纳米硅占负极材料的质量百分含量为30％-60％。
结合第二方面，本申请的部分实施例中，碳材料占负极材料的质量百分含量为10％-65％。
结合第二方面，本申请的部分实施例中，包覆碳层包括碳材料。
第三方面，本申请实施例提供了一种锂离子电池，包括第一方面或第二方面提供的负极材料。
第四方面，本申请实施例提供了一种负极材料的制备方法，包括：
形成基质内或/和表面分布有纳米硅且呈多孔结构或网络结构的Li xM ySiO 4材料；其中，Li xM ySiO 4材料中，M包括除Li以外的能够还原硅氧化物的金属元素；
在Li xM ySiO 4材料的多孔结构的孔道中或网络结构的空隙中填充碳材料得到所述负极材料。
结合第四方面，在本申请的部分实施例中，制备方法包括：
将具有网络结构或多孔结构的骨架材料与锂盐混合，然后进行烧成得到Li xM ySiO 4材料，其中，骨架材料包括纳米硅、负载于纳米硅表面的硅氧化物和金属M氧化物；及在Li xM ySiO 4材料的孔道或空隙中形成碳材料得到负极材料；
或，将具有网络结构或多孔结构的骨架材料、锂盐与有机碳源混合，然后进行热处理得到负极材料，其中，骨架材料包括纳米硅、负载于纳米硅表面的硅氧化物和金属M氧化物。
结合第四方面，在本申请的部分实施例中，在Li xM ySiO 4材料的孔道或空隙中形成碳材料得到负极材料的步骤，包括：将Li xM ySiO 4材料与有机碳源混合并进行煅烧，使有机碳源碳化形成碳材料；或通过化学气相沉积法的方式在Li xM ySiO 4材料的孔道或空隙中形成碳材料；
或，将具有网络结构或多孔结构的骨架材料、锂盐与有机碳源混合的步骤包括：将网络结构或多孔结构的骨架材料与锂盐混合，再与有机碳源混合。
结合第四方面，在本申请的部分实施例中，骨架材料的制备方法，包括：
将硅氧化物和粘结剂混合后进行造粒，得到前驱体一；
将前驱体一、金属M粉和熔融盐混合，并进行热反应使得至少部分所述硅氧化物被还原成纳米硅，得到前驱体二；
将前驱体二进行酸洗去掉部分金属M氧化物，以形成多孔结构或网络结构的骨架材料。
结合第四方面，在本申请的部分实施例中，将硅氧化物和粘结剂分散在溶液中，喷雾造粒得到前驱体一。；
结合第四方面，在本申请的部分实施例中，硅氧化物与粘结剂的质量比为(40-100):1。
结合第四方面，在本申请的部分实施例中，前驱体一、熔融盐和金属M粉的质量比依次为1:(3-8):(0.5-1.5)。
结合第四方面，在本申请的部分实施例中，金属M粉包括Mg粉、Al粉和MgAl合金粉中的一种或多种组合。
结合第四方面，在本申请的部分实施例中，骨架材料、可溶性锂盐和水混合，搅拌均匀以后干燥。
与现有技术相比，本申请的有益效果包括：
对于第一方面的负极材料来说：Li xM ySiO 4材料的添加(M包括除Li以外的能够还原硅氧化物的金属元素)，可以对负极材料补锂，以提高其首效，且Li xM ySiO 4材料具有较好的锂离子和电子传导性，能够提升材料的电导率；网络结构的Li xM ySiO 4材料与网络结构的碳材料相互交缠，网络结构的碳材料基本分布在负极材料的各处，可以使负极材料的导电性较高；同时，由于Li xM ySiO 4材料基质内或/和表面分布有纳米硅，纳米硅的添加可以使材料的容量增大，并且纳米硅的粒径较小，分布较为均匀；虽然纳米硅在充放电的过程中会出现体积膨胀，但是，由于相互交缠的网络结构的Li xM ySiO 4材料和网络结构的碳材料的作用，可以限制纳米硅的膨胀，并且在一定程度上避免纳米硅的体积膨胀造成的结构坍塌。可以使负极材料的导电性较佳，结构更加稳定，并具有较低的体积膨胀、较高的导电性、首效以及优异的倍率性能。
对于第二方面的负极材料来说：Li xM ySiO 4材料的添加(M包括除Li以外的能够还原硅氧化物的金属元素)，可以对负极材料补锂，以提高其首效，且Li xM ySiO 4材料具有较好的锂离子和电子传导性，能够提升材料的电导率；多孔的Li xM ySiO 4材料的孔道中分布有碳材料，可以使负极材料的导电性较高；同时，由于Li xM ySiO 4材料基质内或/和表面分布有纳米硅，纳米硅的添加可以使材料的容量增大，并且纳米硅的粒径较小，分布 较为均匀；虽然纳米硅在充放电的过程中会出现体积膨胀，但是，由于多孔结构的Li xM ySiO 4材料及其孔道中的碳材料的作用，可以限制纳米硅的膨胀，并且在一定程度上避免纳米硅的体积膨胀造成的结构坍塌。可以使负极材料的导电性较佳，结构更加稳定，并具有较低的体积膨胀、较高的导电性、首效以及优异的倍率性能。
对于负极材料的制备方法来说：形成多孔结构或骨架结构的Li xM ySiO 4材料，使纳米硅与Li xM ySiO 4材料之间的分布较为均匀，且纳米硅位于Li xM ySiO 4材料的基质内或/和表面；与碳材料复合以后，得到的负极材料的导电性较佳，结构更加稳定，并具有较低的体积膨胀、较高的导电性、首效以及优异的倍率性能。
对于锂离子电池来说：该锂离子电池使用本申请提供的负极材料，可以使电池具有较低的体积膨胀、较高的首效以及优异的倍率性能。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，应当理解，以下附图仅示出了本申请的某些实施例，因此不应被看作是对范围的限定，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他相关的附图。
图1为本申请实施例提供的负极材料的剖面示意图；
图2为本申请实施例提供的负极材料的制备方法的工艺流程图；
图3为实施例1中前驱体五的扫描电镜图和EDS图；
图4为本申请实施例1提供的负极材料的XRD图；
图5为本申请实施例1提供的负极材料的扫描电镜图；
图标：110-Li xM ySiO 4材料；120-碳材料；130-纳米硅。
具体实施方式
为使本申请实施例的目的、技术方案和优点更加清楚，下面对本申请的技术方案进行清楚、完整地描述。
发明人研究发现，硅可以提高负极材料的容量，但其容易造成体积膨胀，且硅表面的氧化层会造成电池的首效降低；碳可以提高负极材料的导电性，但其容量较低；Li xM ySiO 4可以对负极材料补锂，以提高首效，且Li xM ySiO 4材料具有较好的锂离子和电子传导性，能够提升材料的电导率。所以，发明人提供一种负极材料，将三者进行复合，以使负极材料具有较低的体积膨胀、较高的导电性、首效以及优异的倍率性能。
图1为本申请实施例提供的负极材料的剖面示意图。请参阅图1，图1中，黑色部分为Li xM ySiO 4材料110，白色部分为纳米硅130，灰色部分为碳材料120。
请继续参阅图1，该负极材料包括相互交缠的第一骨架和第二骨架，以及纳米硅130，第一骨架包括Li xM ySiO 4材料110，第二骨架包括碳材料120；其中，Li xM ySiO 4材料110基质内或/和表面分布有纳米硅130。其中，Li xM ySiO 4材料中，x、y的取值符合电荷平衡，M包括除Li以外的能够还原硅氧化物的金属元素。
第一骨架和第二骨架相互交缠形成复合骨架，第一骨架的Li xM ySiO 4材料110内交缠有第二骨架的碳材料120，第二骨架的碳材料120内交缠有第一骨架的Li xM ySiO 4材料110，可以使负极材料的结构更加稳定；同时，整个负极材料内基本均匀分布有碳材料120，可以使材料的导电性更强。
Li xM ySiO 4材料110的添加(M包括除Li以外的能够还原硅氧化物的金属元素)，可以对负极材料补锂，以提高其首效，纳米硅130分布在 Li xM ySiO 4材料110基质内或/和表面，可以使负极材料的容量增大；虽然纳米硅130在充放电的过程中会出现体积膨胀，但是，由于相互交缠的Li xM ySiO 4材料110和碳材料120的作用，可以限制纳米硅130的膨胀，并且在一定程度上避免纳米硅130的体积膨胀造成的结构坍塌。可以使负极材料的导电性较佳，结构更加稳定，并具有较低的体积膨胀、较高的导电性、首效以及优异的倍率性能。
Li xM ySiO 4材料110和碳材料120可以均为网络结构。由于相互交缠的网络结构的Li xM ySiO 4材料110和网络结构的碳材料120的作用，可以更好地限制纳米硅130的膨胀，避免纳米硅130的体积膨胀造成的结构坍塌。可以使负极材料的导电性更佳，结构更加稳定，并具有较低的体积膨胀、较高的导电性、首效以及优异的倍率性能。
需要说明的是：此处的网络结构并不是指无形的计算机网络的结构，而是指有形物质的网络结构，该网络结构是相当于实心结构而言的。例如：一个球状材料，如果其内部没有空隙，与球状材料的表层结构一致，则称其为实心结构；如果其内部有一个大空隙，则称其为空心结构；如果内部有很多空隙，该空隙可能会有部分导通，则称其为网络结构。
又例如：如果一种材料叫金属网，其通常的结构是多根金属丝编织在一起，形成具有多个孔洞结构的金属网。本申请中的网络结构与此具有一定的差异，本申请中的网络结构，其基体基本为立体三维结构(例如：球状结构、正方体结构、长方体结构，以及其他的不规则立体结构)，内部和表面具有很多孔道(例如：类似于三维的泡沫金属结构，但其材质不同，孔道的结构也有可能不同)，从而形成的网络结构。
所以，本申请中的网络结构是指立体的Li xM ySiO 4材料110和碳材料120内部和表面具有很多空隙，从而可以使二者的空隙与材料之间相互交 缠的结构。此处网络结构的空隙并不限定为均匀分布的空隙，其可以在部分区域空隙较大，部分区域空隙较小，其可以是不规则的空隙。
纳米硅130分布在Li xM ySiO 4材料110基质内或/和表面，是指Li xM ySiO 4材料110的表面分布有纳米硅130；或Li xM ySiO 4材料110的基质内分布有纳米硅130；或Li xM ySiO 4材料110的表面和基质内均分布有纳米硅130。
纳米硅130主要是指颗粒尺寸为纳米级的硅材料，该颗粒尺寸的硅材料的粒径较小，在硅含量相同的条件下，粒径较小的纳米硅130更加容易均匀分布在Li xM ySiO 4材料110上。
虽然本申请记载纳米硅130分布在Li xM ySiO 4材料110基质内或/和表面，但是，其并不限定Li xM ySiO 4材料110的质量大于纳米硅130的质量。实际上，Li xM ySiO 4材料110的质量可以大于纳米硅130的质量，纳米硅130的质量也可以大于Li xM ySiO 4材料110的质量，Li xM ySiO 4材料110的质量还可以与纳米硅130的质量相当。
请继续参阅图1，该负极材料包括Li xM ySiO 4材料110、碳材料120和纳米硅130，Li xM ySiO 4材料110为多孔结构，Li xM ySiO 4材料110的孔道内填充碳材料120；其中，Li xM ySiO 4材料110基质内或/和表面分布有纳米硅130，x、y的取值符合电荷平衡，M包括除Li以外的能够还原硅氧化物的金属。
多孔结构的Li xM ySiO 4材料110的孔道中填充有碳材料120，可以使负极材料的结构更加稳定；同时，整个负极材料内基本均匀分布有碳材料120，可以使材料的导电性更强。Li xM ySiO 4材料110的添加(M包括除Li以外的能够还原硅氧化物的金属元素)，可以对负极材料补锂，以提高其首效，纳米硅130分布在Li xM ySiO 4材料110基质内或/和表面，可以使 负极材料的容量增大；虽然纳米硅130在充放电的过程中会出现体积膨胀，但是，由于相互填充的多孔结构的Li xM ySiO 4材料110和多孔结构的碳材料120的作用，可以限制纳米硅130的膨胀，并且在一定程度上避免纳米硅130的体积膨胀造成的结构坍塌。可以使负极材料的导电性较佳，结构更加稳定，并具有较低的体积膨胀、较高的导电性、首效以及优异的倍率性能。
作为示例性地，多孔结构的Li xM ySiO 4材料110的孔隙率为30％-46％，例如30％、32％、35％、40％、43％、46％等，即保证Li xM ySiO 4材料有充足的体积来填充碳材料，提高了复合负极材料的导电性、降低复合负极材料的膨胀率，又可以保证容量不会过低。
需要说明的是：碳材料120也可以看作是多孔结构，此处的多孔结构是指：Li xM ySiO 4材料110和碳材料120基本为立体结构，其内部和/或表面具有很多孔道，该孔道可以有部分连通，也可以有部分未连通，使两种材料能够相互填充。此处多孔结构的孔道也并不限定为均匀分布的孔道，也不限定为孔径一致的孔道，其可以在部分区域孔道较大，部分区域孔道较小，其可以是不规则的孔道。
不管是多孔结构还是网络结构，可选地，碳材料120的骨架直径为10nm-500nm；Li xM ySiO 4材料110的骨架直径为10nm-400nm；其并不限定为碳材料120和Li xM ySiO 4材料110的所有骨架的直径均在上述范围之内，一般70％以上的骨架的直径在上述范围内，就容易实现Li xM ySiO 4材料110和碳材料120的相互填充或相互交缠。同时，其也并不限定不同部位的骨架直径相同，同一颗粒的骨架的不同部位的直径可以不同。
作为示例性地，碳材料120的骨架直径为10nm-100nm，Li xM ySiO 4材料110的骨架直径为10nm-90nm；或碳材料120的骨架直径为100nm-300nm，Li xM ySiO 4材料110的骨架直径为90nm-200nm；或碳材料120 的骨架直径为300nm-500nm，Li xM ySiO 4材料110的骨架直径为200nm-400nm。其中，骨架直径可以通过扫描电镜观察得到。
请继续参阅图1，Li xM ySiO 4材料的孔道中填充的碳材料还分布在Li xM ySiO 4材料的外表面，形成包覆碳层。包覆碳层的形成，一方面，可以使负极材料的导电性更佳；另一方面，可以限制纳米硅130的体积膨胀；再一方面，还可以对内部的结构进行保护，使整个材料的结构更加稳定。
下面对包覆碳层进行解释，例如：如图1所示，多孔结构的Li xM ySiO 4材料110的直径为D1(Li xM ySiO 4材料110虽然为多孔结构或网络结构，但是，基本的外轮廓为球状，该球状外轮廓的直径为D1)，则填充在多孔结构的Li xM ySiO 4材料内的填充碳的直径也为D1(填充碳也为多孔结构，但是，基本的外轮廓为球状，该球状外轮廓的直径为D1)，负极材料的粒径为D2，则包覆碳层是指图1中D2所在的球形减去D1所在的球形的区域。包覆碳层是指包覆在Li xM ySiO 4材料110以外的碳层结构，其基本不与Li xM ySiO 4材料110之间有相互交缠或相互填充的关系。
可选地，包覆碳层的厚度为5nm-80nm。此处的包覆碳层的厚度是指碳层中基本没有Li xM ySiO 4材料110的最外层厚度，例如：图1中D的值，其值为(D2-D1)/2。该厚度的包覆碳层，一方面，可以使材料的结构较为稳定；另一方面，可以有效限制硅的体积膨胀；再一方面，还可以使纳米硅130和Li xM ySiO 4材料110的质量占比较为合理，以便使负极材料的综合性能较佳。
作为示例性地，包覆碳层的厚度可以为5nm-20nm；或包覆碳层的厚度可以为20nm-40nm；或包覆碳层的厚度可以为40nm-60nm；或包覆碳层的厚度可以为60nm-80nm。需要说明的是：如图1所示，包覆碳层大概是 一个球形的层状结构，该球形的不同位置的厚度可以相同，也可以不同，本申请不做限定。
需要说明的是，图1中，不管是网络结构或多孔结构的Li xM ySiO 4材料110的外轮廓为球状结构，或者颗粒状的负极材料的外轮廓为球状结构，其仅仅是一种示例性的形状或结构，其并不限定为一定是球状结构，其类似球状结构，或者能够形成颗粒状的方案均在本申请的保护范围之内。
可选地，Li xM ySiO 4材料110中，2≤x≤3.4，0.4≤y≤1，x、y的取值符合电荷平衡。
在一些可能的实施方式中，M包括Mg或/和Al，一方面，其容易与硅氧化物以及金属氧化物反应得到Li xM ySiO 4材料110；另一方面，其来源较广，较为容易得到；再一方面，其预锂化效果较好，负极材料的性能更佳。
可选地，Li xM ySiO 4材料110可以是硅酸镁锂；或Li xM ySiO 4材料110可以是硅酸铝锂；或Li xM ySiO 4材料110可以是硅酸镁锂和硅酸铝锂的混合物。
在其他实施方式中，M还可以包括Ca或/和Zn。
在一些可能的实施方式中，纳米硅130的粒径为5nm-200nm；纳米硅130更加容易均匀分布在Li xM ySiO 4材料110上，并且，此粒径的纳米硅130可以直接通过硅氧化物还原得到，制备也更加方便。
Li xM ySiO 4材料110上分布有很多纳米硅130，此时，每颗纳米硅130的粒径并不限定为一致，一般情况下，纳米硅130的粒径基本在一个范围内，纳米硅130的颗粒分布较为均匀。作为示例性地，纳米硅130的粒径为5nm-50nm；或纳米硅130的粒径为50nm-100nm；或纳米硅130的粒径为100nm-150nm；或纳米硅130的粒径为150nm-200nm。
在一些可能的实施方式中，碳材料120包括硬碳、软碳中的一种或多种组合。
在一些可能的实施方式中，负极材料的比表面积为1m 2/g-3m 2/g。该负极材料的比表面积较小，基本没有孔隙或有少量的孔隙，是整个负极材料的结构更加稳定。
例如：负极材料的比表面积为1m 2/g、1.5m 2/g、2m 2/g、2.5m 2/g或3m 2/g。
可选地，负极材料的形状为球状颗粒，负极材料的颗粒平均粒径D50为5μm-30μm。此处的球状颗粒并不限定为规则的球状，其可以为不规则球状颗粒，比如：表面有少量的凹陷部位，整体结构为椭球结构等。此处的平均粒径可以是指的不同颗粒的粒径平均值，也可以是指同一颗粒的不同方向的粒径平均值，此处不做限定。
球状颗粒的负极材料的颗粒平均粒径D50在5μm-30μm的范围内，可以使负极材料的尺寸较为均匀，以便其容量保持率较高，性能较佳。作为示例性地，负极材料的颗粒平均粒径D50为5μm-10μm；或负极材料的颗粒平均粒径D50为10μm-20μm；或负极材料的颗粒平均粒径D50为20μm-30μm。
例如：球状颗粒的负极材料的颗粒平均粒径D50为5μm、8μm、10μm、15μm、20μm、25μm或30μm。
在一些可能的实施方式中，Li xM ySiO 4材料110占负极材料的质量百分含量为5％-30％，纳米硅130占负极材料的质量百分含量为30％-60％，碳材料120占负极材料的质量百分含量为10％-65％。Li xM ySiO 4材料110、纳米硅130和碳材料120的含量限定在上述范围内，可以使负极材料的组成更加合理，能够使负极材料的综合性能更佳。
在一个实施方式中，Li xM ySiO 4材料110占负极材料的质量百分含量为5％-10％，纳米硅130占负极材料的质量百分含量为30％-40％，碳材料120占负极材料的质量百分含量为50％-65％。该范围中，Li xM ySiO 4材料 110的含量相对较少，纳米硅130和碳材料120的含量相对较多，可以有效提高负极材料的首效；同时，较多碳材料120的添加，能够有效限制纳米硅130在充放电过程中的膨胀，负极材料的性能较佳。
在另一个实施方式中，Li xM ySiO 4材料110占负极材料的质量百分含量为10％-20％，纳米硅130占负极材料的质量百分含量为30％-40％，碳材料120占负极材料的质量百分含量为50％-60％。
在另一个实施方式中，Li xM ySiO 4材料110占负极材料的质量百分含量为20％-30％，纳米硅130占负极材料的质量百分含量为40％-60％，碳材料120占负极材料的质量百分含量为10％-30％。
例如：Li xM ySiO 4材料110占负极材料的质量百分含量为5％，纳米硅130占负极材料的质量百分含量为60％，碳材料120占负极材料的质量百分含量为35％；或，Li xM ySiO 4材料110占负极材料的质量百分含量为10％，纳米硅130占负极材料的质量百分含量为50％，碳材料120占负极材料的质量百分含量为40％；或，Li xM ySiO 4材料110占负极材料的质量百分含量为20％，纳米硅130占负极材料的质量百分含量为45％，碳材料120占负极材料的质量百分含量为35％；或，Li xM ySiO 4材料110占负极材料的质量百分含量为30％，纳米硅130占负极材料的质量百分含量为30％，碳材料120占负极材料的质量百分含量为40％。
上述的负极材料可以用来制备锂离子电池，制备得到的锂离子电池具有较低的体积膨胀、较高的首效以及优异的倍率性能。
该锂离子电池可以用来对用电装置提供电能，其续航能力更佳。
上面介绍了负极材料及其应用以后，下面对其制备方法进行介绍。该方法包括：形成多孔结构或网络结构的Li xM ySiO 4材料，在Li xM ySiO 4材料的多孔结构的孔道中或网络结构的空隙中填充碳材料得到负极材料，其中M包括除Li以外的能够还原硅氧化物的金属元素。
基于纳米硅表面的硅氧化物来形成多孔结构或网络结构的Li xM ySiO 4材料，使纳米硅与Li xM ySiO 4材料之间的分布较为均匀，且纳米硅位于Li xM ySiO 4材料的基质内或/和表面；与碳材料复合以后，得到的负极材料的导电性较佳，结构更加稳定，并具有较低的体积膨胀、较高的导电性、首效以及优异的倍率性能。
下面对其制备方法进行具体介绍，图2为本申请实施例提供的负极材料的制备方法的工艺流程图，请参阅图2，该制备方法包括：
S110将硅氧化物和粘结剂混合后进行造粒，得到前驱体一。通过粘结剂的添加进行造粒，一方面可以使颗粒较为均匀；另一方面，后续容易形成具有多孔结构或网络结构的骨架。
可选地，将硅氧化物和粘结剂分散在溶液中，喷雾造粒得到前驱体一。可以使硅氧化物和粘结剂的分散更加均匀，以便得到粒径更加均匀的颗粒。
在一些可能的实施范式中，硅氧化物与粘结剂的质量比为(40-100):1。硅氧化物的含量大大高于粘结剂的含量，造粒后的前驱体一的主要成分为硅氧化物，粘结剂只是作为粘接材料进行使用，以便进行造粒。
作为示例性地，硅氧化物与粘结剂的质量比为(40-60):1；或硅氧化物与粘结剂的质量比为(60-80):1；或硅氧化物与粘结剂的质量比为(80-100):1。例如：硅氧化物与粘结剂的质量比为40:1、50:1、60:1、70:1、80:1、90:1或100:1等。
在一些可能的实施方式中，硅氧化物为SiO、SiO 2、Si 2O 6中的一种或多种组合。例如：硅氧化物为二氧化硅，其较为稳定，来源更广。
在一些可能的实施方式中，粘结剂为环氧树脂、酚醛树脂、糠醛树脂、脲醛树脂、聚乙烯醇、聚氯乙烯、聚乙二醇、聚环氧乙烷、聚偏氟乙烯、葡萄糖、蔗糖、沥青、聚苯乙烯、聚吡咯、聚苯胺、羧甲基纤维素钠、聚乙烯吡咯烷酮中的一种或多种组合。
可选地，将硅氧化物分散在水溶液中，搅拌均匀后向溶液中加入粘结剂，硅氧化物与粘结剂的质量比为(40-60):1，继续搅拌均匀以后喷雾造粒，得到前驱体一。
S120将前驱体一、金属M粉和熔融盐混合，并进行热反应使得至少部分硅氧化物被还原成纳米硅，得到前驱体二。其中，M包括除Li以外的能够还原硅氧化物的金属元素。在进行热反应的过程中，硅氧化物被金属M还原成纳米硅，金属M转化成金属M氧化物，形成的颗粒基本为内壳是纳米硅，表层为金属M氧化物的结构，并且，颗粒与颗粒之间分布有熔融盐。
需要说明的是：此处并不限定所有的硅氧化物均被还原，也不限定纳米硅的表层全部附着有金属M氧化物；实际成产过程中，更多的情况是大部分硅氧化物被还原，纳米硅上的金属M氧化物一般情况下覆盖了纳米硅的部分表层，可能还有部分纳米硅的表面露出。
同时，并不是纳米硅颗粒(内部为纳米硅，表层具有金属氧化物的颗粒)与颗粒之间全部分布有熔融盐，可以一部分纳米硅之间分布熔融盐，也可以一部分纳米硅与纳米硅之间结合在一起。
熔融盐的添加，可以控制热反应的反应情况，在一定程度上避免反应的剧烈进行；同时，还可以避免颗粒之间的粘接或团聚，以便最后形成颗粒更加均匀的负极材料，且反应也更加容易控制；在后续去除熔融盐以后，还有利于形成多孔结构。
在一些可能的实施方式中，前驱体一、熔融盐和金属M粉的质量比依次为1:(3-8):(0.5-1)。熔融盐的含量较多，其基本不参与反应，后续去除熔融盐以后，可以形成多孔结构或网络结构，以便负极材料的制备；前驱体一与金属M粉的质量比在上述范围内，以便可以还原更多的硅氧化物，并得到纳米硅。
作为示例性地，前驱体一、熔融盐和金属M粉的质量比依次为1:(3-5):(0.8-1)；或前驱体一、熔融盐和金属M粉的质量比依次为1:(5-8):(0.5-0.8)；或前驱体一、熔融盐和金属M粉的质量比依次为1:(3-6):(0.5-0.7)。
例如：前驱体一、熔融盐和金属M粉的质量比依次为1:3:0.8、1:4:0.8、1:5:0.8、1:6:0.8、1:7:0.8、1:8:0.8、1:3:0.9、1:4:0.9、1:5:0.9、1:6:0.9、1:7:0.9、1:8:0.9、1:3:1、1:4:1、1:5:1、1:6:1、1:7:1或1:8:1等。
在一些可能的实施方式中，金属M粉包括Mg粉、Al粉和MgAl合金粉中的一种或多种组合。由于热反应的过程中发生氧化还原反应，所以，金属M粉与硅氧化物接触，形成的金属M氧化物较多的形成在纳米硅的表面，但并不限定全部在纳米硅表面，一部分金属M氧化物也可能并没有形成在纳米硅的表面，此处不做限定。
在其他实施例方式中，金属M粉还可以包括钙粉、锌粉等。
在一些可能的实施方式中，熔融盐为氯化镁、氯化钠、氯化钾、氯化钙、氯化铜、硫酸钠、硫酸钙、硫酸钡、硫酸铝、硝酸钠、硝酸钾、硝酸铵、硝酸钙、硝酸铅、硝酸铈、氟化钠、氟化钾、氟化钙中的一种或多种组合。
可选地，热反应的条件是：在惰性气体气氛中，温度为400℃-800℃的条件下反应1h-10h。在惰性气体气氛中反应，金属M粉基本不会被氧气氧化，而是与硅氧化物发生氧化还原反应，以便使硅氧化物转化成纳米硅；热反应的温度以及时间在上述范围内，可以使硅氧化物的还原效果更好。
作为示例性地，热反应的条件是：在氮气气氛中，温度为400℃-500℃的条件下反应8h-10h；或，在氮气气氛中，温度为500℃-600℃的条件下反应6h-8h；或，在氮气气氛中，温度为600-700℃的条件下反应1h-6h；或，在氮气气氛中，温度为700℃-800℃的条件下反应1h-6h。
可选地，将前驱体一、金属M粉和熔融盐混合，前驱体一、熔融盐和金属M粉的质量比依次为1:(3-8):(0.5-1.5)；混合后置于氮气气氛中，在温度为400℃-800℃的条件下反应1h-10h，得到前驱体二。
S130将前驱体二进行酸洗去掉部分金属M氧化物，以形成前驱体三。酸洗步骤在酸溶液中进行，前驱体二与酸溶液混合以后，纳米硅表面的部分金属M氧化物溶解在酸溶液中；熔融盐溶解在酸溶液中，形成纳米硅的集合为多孔结构或网络结构，纳米硅表面可能有一部分被金属M氧化物附着，一部分暴露出来。该前驱体三为网络结构或多孔结构的骨架材料，骨架材料包括纳米硅、负载于纳米硅表面的硅氧化物和金属M氧化物，其中，硅氧化物可以是未被还原的硅氧化物，也可以是纳米硅暴露出来以后在表层自然形成的硅氧化物。
在一些可能的实施方式中，酸溶液为硝酸溶液、盐酸溶液和硫酸溶液中的一种或多种组合。
可选地，硝酸溶液的质量浓度为5％-15％；盐酸溶液的质量浓度为5％-15％；硫酸溶液的质量浓度为5％-15％。
可选地，酸溶液的添加量是前驱体二质量的10％-120％。作为示例性地，酸溶液的添加量是前驱体二质量的10％-30％；或，酸溶液的添加量是前驱体二质量的30％-50％；或，酸溶液的添加量是前驱体二质量的50％-80％；或，酸溶液的添加量是前驱体二质量的80％-120％。
例如：酸溶液的添加量是前驱体二质量的10％、20％、30％、40％、50％、60％、70％、80％、90％、100％、110％或120％。
可选地，将前驱体二与质量浓度为5％-15％的盐酸溶液混合并浸渍0.3h-1h，通过酸溶液的浓度以及浸渍的时间的配合，可以将部分金属氧化物去除，然后水洗固液分离后去除杂质(其中，固液分离的方式可以是离心、过滤、抽滤等)，干燥得到多孔结构或网络结构的骨架材料，骨架材料包括纳米硅、负载于纳米硅表面的硅氧化物和金属M氧化物。
需要说明的是，步骤S110-步骤S130可以实施，也可以不实施，使用其他方式也可以得到多孔结构或网络结构的骨架材料。
S140将前驱体三与锂盐混合并进行烧成得到多孔结构或网络结构的Li xM ySiO 4材料。其中，Li xM ySiO 4材料基质内或/和表面分布有纳米硅，x、y的取值符合电荷平衡。
使用一定浓度的酸溶液浸泡前驱体二一定的时间，可以使前驱体二中的部分金属M氧化物被去除，较多的纳米硅暴露出来，且形成孔道结构(多孔结构或网络结构的骨架)；将锂盐与前驱体三混合以后，锂盐会与纳米硅、金属M氧化物以及硅氧化物(该硅氧化物可以是未被还原的硅氧化物，也可以是纳米硅暴露出来以后在表层自然形成的硅氧化物。)接触，在烧成的时候，部分硅氧化物、金属M氧化物与锂盐反应，得到多孔结构或网络结构的Li xM ySiO 4材料；此时，Li xM ySiO 4材料的基质内或/和表面均分布有纳米硅。
在一些可能的实施方式中，锂盐为醋酸锂、草酸锂、碳酸锂、氢氧化锂、甲酸锂、苯甲酸锂、氯化锂、硫酸锂、硝酸锂中的一种或多种组合。
可选地，烧成的条件是：在惰性气体气氛中，温度为600℃-1200℃的条件下烧成1h-10h。作为示例性地，烧成的条件是：在氮气气氛中，温度为600℃-800℃的条件下反应8h-10h；或，在氮气气氛中，温度为800℃-1000℃的条件下反应5h-8h；或，在氮气气氛中，温度为1000℃-1200℃的条件下反应1h-5h。
可选地，前驱体三、可溶性锂盐和水混合，搅拌均匀以后干燥；惰性气体气氛中，温度为600℃-1200℃的条件下烧成1h-10h，得到Li xM ySiO 4材料。
使用可溶性锂盐在水中与前驱体三混合，可以使前驱体三的表面均匀吸附一层可溶性锂盐，干燥以后，锂盐吸附在前驱体三的表面，在后续进 行烧成的时候，方便控制Li xM ySiO 4材料的量，且还可以使纳米硅均匀分布在Li xM ySiO 4材料上。
S150在Li xM ySiO 4材料的孔道中形成碳材料得到负极材料。由于Li xM ySiO 4材料是多孔结构或网络结构，且Li xM ySiO 4材料基质内或/和表面分布有纳米硅，Li xM ySiO 4材料内部具有很多孔道，碳材料形成在Li xM ySiO 4材料的孔道中，与Li xM ySiO 4材料相互填充或相互交缠，得到负极材料。且如果碳材料形成的质量较多，还可以在表面形成了包覆碳层，得到性能较佳的负极材料。
在一种实施方式中，将Li xM ySiO 4材料与有机碳源混合并进行煅烧，使有机碳源碳化形成碳材料。Li xM ySiO 4材料与有机碳源混合以后，会有一部分有机碳源进入到Li xM ySiO 4材料的孔道中，一部分有机碳源包覆在Li xM ySiO 4材料的表面，在进行煅烧的时候，可以形成与Li xM ySiO 4材料相互填充的碳材料，并在表面形成包覆碳层。
其中，有机碳源为聚合物、糖类、有机酸、沥青和高分子材料中的一种或多种组合；例如：有机碳源为聚氯乙烯、聚乙烯醇缩丁醛、蔗糖、葡萄糖、柠檬酸、沥青、糠醛树脂、环氧树脂、酚醛树脂、聚丙烯酸等。
可选地，Li xM ySiO 4材料与有机碳源的混合方式可以为热压包覆的方式，将Li xM ySiO 4材料和有机碳源混合均匀后放置于烧成炉中，在惰性气体氛围中，5Mpa-20Mpa的压力，温度为700℃-1200℃的条件下煅烧1h-10h，使有机碳源碳化。
通过热压包覆的方式，可以将有机碳源热压至多孔结构的Li xM ySiO 4材料的孔道或空隙内，以便后续有机碳源碳化以后，在多孔结构的Li xM ySiO 4材料的孔道或空隙内填充碳材料。
作为示例性地，有机碳源碳化的条件是：在氮气气氛中，温度为700℃-800℃的条件下反应8h-10h；或，在氮气气氛中，温度为800℃-1000℃的 条件下反应5h-8h；或，在氮气气氛中，温度为1000℃-1200℃的条件下反应1h-5h。
热压烧成炉的压力5Mpa-20Mpa，压力较高，由于煅烧的过程中，有机碳源碳化以后，体积会减小，所以，可以一边煅烧一边使碳材料热压至多孔结构的Li xM ySiO 4材料内，以便形成的多孔结构的碳材料和多孔结构的Li xM ySiO 4材料之间的交缠更加紧密，填充更紧密，负极材料的性能更佳。
作为示例性地，有机碳源碳化的条件是：在压力为5Mpa-10Mpa、温度为700℃-800℃的惰性气体气氛中反应8h-10h；或，在压力为10Mpa-15Mpa、温度为800℃-1000℃的惰性气体气氛中反应5h-8h；或，在压力为15Mpa-20Mpa、温度为1000℃-1200℃的惰性气体气氛中反应1h-5h。
在另一实施方式中，将Li xM ySiO 4材料置于化学气相沉积炉中，通过化学气相沉积法的方式在Li xM ySiO 4材料的孔道中和表面形成碳材料。通过化学气相沉积法形成碳材料并填充在Li xM ySiO 4材料的孔道中，其填充效果较好，即使孔道较小，也能够通过气源进入到多孔结构的Li xM ySiO 4材料内，形成相互交缠的多孔结构的碳材料与多孔结构的Li xM ySiO 4材料。
可选地，化学气相沉积法的条件是：采用乙炔、甲烷或丙酮为碳源，采用氩气或氮气做保护气体，在750℃-1200℃气相沉积。
需要说明的是，前述的步骤S140和步骤S150是分开通过烧成和煅烧两次进行的，但本申请并不限定其分两次进行，其也可以通过一次热处理进行制备。
可选地，将前驱体三与锂盐与有机碳源混合，然后进行热处理得到负极材料，其中，前驱体三为多孔结构或网络结构的骨架材料，骨架材料包括纳米硅、纳米硅表面的硅氧化物和金属氧化物。
在进行热处理的时候，既可以使部分纳米硅、硅氧化物、金属氧化物与锂盐反应，得到多孔结构或网络结构的Li xM ySiO 4材料；同时，又可以使有机碳源碳化，使碳化后的碳材料与Li xM ySiO 4材料相互填充或相互交缠。
可选地，将前驱体三与锂盐混合，再与有机碳源混合然后进行热处理得到负极材料。例如：前驱体三、可溶性锂盐和水混合，搅拌均匀以后干燥；然后将有机碳源包覆在其表面和内部，并在惰性气体氛围中，温度为700℃-1200℃的条件下热处理1h-10h，使有机碳源碳化形成碳材料，同时，锂盐发生反应得到Li xM ySiO 4材料。
通过上述方法制备得到的负极材料，其包括交互交缠或相互填充的Li xM ySiO 4材料和碳材料，且Li xM ySiO 4材料基质内或/和表面分布有纳米硅，可以使负极材料的结构更加稳定，并具有较低的体积膨胀、较高的导电性、首效以及优异的倍率性能。
为使本申请实施例的目的、技术方案和优点更加清楚，下面将对本申请实施例中的技术方案进行清楚、完整地描述。实施例中未注明具体条件者，按照常规条件或制造商建议的条件进行。所用试剂或仪器未注明生产厂商者，均为可以通过市售购买获得的常规产品。
实施例1
一种负极材料的制备方法，包括如下步骤：
(1)取500g的纳米二氧化硅，将其分散在10Kg的水溶液中，搅拌均匀后向其中加入10g的羧甲基纤维素钠，搅拌均匀后喷雾造粒，得到前驱体一。
(2)将前驱体一与熔融氯化钠、镁粉混合，混合比例前驱体一、氯化钠和镁粉的质量比依次为1:5:0.8，混合均匀后置于氮气气氛中700℃反应5h得到前驱体二。
(3)将前驱体二置于水溶液中，前驱体二与水的比例为1:4，搅拌均匀后向其中加入与前驱体二重量比为1:1的工业盐酸溶液，反应0.5h后离心，水洗去除杂质，得到前驱体三。
(4)将前驱体三分散于水溶液中，骨架材料与水的比例为1:5，向其中加入与骨架材料重量比为10:1的碳酸锂，搅拌条件下将溶剂蒸干，得到前驱体四。
(5)将前驱体四置于回转炉中，在惰性气体条件下1100℃烧成3h得到前驱体五。
(6)将前驱体五与沥青混合后，放置于热压烧成炉中，在10Mpa的压力下800℃煅烧3h，将煅烧后的料粉碎、筛分得到负极材料。
图3为实施例1中前驱体五的扫描电镜图(图3中左边图)和EDS图(图3中右边图)，从图3可以看出，前驱体五为多孔结构，且其包含硅酸镁锂材料和纳米硅，且纳米硅在硅酸镁锂基质中均匀分散。
图4为实施例1提供的负极材料的XRD图，从图4可以看出，实施例1提供的负极材料中含有Li xMg ySiO 4材料、碳材料和纳米硅。
图5为实施例1提供的负极材料的扫描电镜图，从图5可以看出，该负极材料较为均匀，其表面均有包覆碳层。
结合上述的附图以及方法分析可知，本实施例得到的负极材料，其包括相互交缠的第一骨架、第二骨架和纳米硅，第一骨架为网络结构的硅酸镁锂材料，第二骨架为网络结构的碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
结合上述的附图以及方法分析可知，本实施例得到的负极材料，其包括硅酸镁锂材料、碳材料和纳米硅，硅酸镁锂材料为多孔结构，硅酸镁锂材料的孔道内填充碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
实施例2
本实施例与实施例1的方法步骤基本一致，其不同在于：步骤(5)和步骤(6)合并为：将前驱体四与沥青混合后，放置于热压烧成炉中，在10Mpa的压力下800℃热处理3h，将热处理后的料粉碎、筛分得到负极材料。
结合扫描电镜图、EDS图和XRD图，以及方法步骤的内容分析可知，通过一次热处理，既可以使碳酸锂反应得到硅酸镁锂材料，又可以使沥青碳化得到碳材料，并且使二者呈相互交缠或相互填充的结构。
本实施例得到的负极材料，其包括相互交缠的第一骨架、第二骨架和纳米硅，第一骨架为网络结构的硅酸镁锂材料，第二骨架为网络结构的碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
本实施例得到的负极材料，其包括硅酸镁锂材料、碳材料和纳米硅，硅酸镁锂材料为多孔结构，硅酸镁锂材料的孔道内填充碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
实施例3
本实施例与实施例1的方法步骤基本一致，其不同在于：步骤(6)中，将前驱体五与沥青混合后，放置于烧成炉中，在800℃煅烧3h，将煅烧后的料粉碎、筛分得到负极材料。
结合扫描电镜图、EDS图和XRD图，以及方法步骤的内容分析可知，在煅烧的过程中，即使不进行热压处理，也可以通过煅烧使沥青碳化得到碳材料，并且能够使碳材料填充在硅酸镁锂材料的孔道中。
本实施例得到的负极材料，其包括相互交缠的第一骨架、第二骨架和纳米硅，第一骨架为网络结构的硅酸镁锂材料，第二骨架为网络结构的碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
本实施例得到的负极材料，其包括硅酸镁锂材料、碳材料和纳米硅，硅酸镁锂材料为多孔结构，硅酸镁锂材料的孔道内填充碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
实施例4
本实施例与实施例1的方法步骤基本一致，其不同在于：步骤(6)中，将前驱体五放置于化学气相沉积炉中，通入甲烷，在800℃沉积3h，沉积后的料粉碎、筛分得到负极材料。
结合扫描电镜图、EDS图和XRD图，以及方法步骤的内容分析可知，在通过化学气相沉积法也可以在硅酸镁锂材料的孔道或空隙中形成碳材料。
本实施例得到的负极材料，其包括相互交缠的第一骨架、第二骨架和纳米硅，第一骨架为网络结构的硅酸镁锂材料，第二骨架为网络结构的碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
本实施例得到的负极材料，其包括硅酸镁锂材料、碳材料和纳米硅，硅酸镁锂材料为多孔结构，硅酸镁锂材料的孔道内填充碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
实施例5
本实施例与实施例1的方法步骤基本一致，其不同在于：步骤(2)中，将前驱体一与氯化钠、铝粉混合，混合比例前驱体一、氯化钠和铝粉的质量比依次为1:5:0.9，混合均匀后置于氮气气氛中700℃反应5h得到前驱体二。
结合扫描电镜图、EDS图和XRD图，以及方法步骤的内容分析可知，该方法使用铝粉还原二氧化硅，最后形成了硅酸铝锂材料。
本实施例得到的负极材料，其包括相互交缠的第一骨架、第二骨架和纳米硅，第一骨架为网络结构的硅酸铝锂材料，第二骨架为网络结构的碳材料；其中，硅酸铝锂材料基质内和表面分布有纳米硅。
本实施例得到的负极材料，其包括硅酸铝锂材料、碳材料和纳米硅，硅酸镁锂材料为多孔结构，硅酸铝锂材料的孔道内填充碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
实施例6
本实施例与实施例1的方法步骤基本一致，其不同在于：步骤(2)中，将前驱体一与氯化钠、镁粉、铝粉混合，混合比例前驱体一、氯化钠、镁粉和铝粉的质量比依次为1:5:0.45:0.4，混合均匀后置于氮气气氛中700℃反应5h得到前驱体二。
结合扫描电镜图、EDS图和XRD图，以及方法步骤的内容分析可知，该方法使用铝粉和镁粉同时还原二氧化硅，最后形成了硅酸铝锂材料和硅酸镁锂材料。
本实施例得到的负极材料，其包括相互交缠的第一骨架、第二骨架和纳米硅，第一骨架为网络结构的硅酸铝锂和硅酸镁锂的混合材料，第二骨架为网络结构的碳材料；其中，硅酸铝锂和硅酸镁锂的混合材料基质内和表面分布有纳米硅。
本实施例得到的负极材料，其包括硅酸铝锂和硅酸镁锂的混合材料、碳材料和纳米硅，硅酸镁锂和硅酸镁锂的混合材料为多孔结构，硅酸铝锂材料的孔道内填充碳材料；其中，硅酸镁锂和硅酸镁锂的混合材料基质内和表面分布有纳米硅。
实施例7本实施例与实施例1的方法步骤基本一致，其不同在于：
步骤(3)中将前驱体二置于水溶液中，前驱体二与水的比例为1:4，搅拌均匀后向其中加入与前驱体二重量比为10:8的工业盐酸溶液，反应0.5h后离心，水洗去除杂质，得到前驱体三。
步骤(4)将前驱体三分散于水溶液中，骨架材料与水的比例为1:5，向其中加入与骨架材料重量比为8:1的碳酸锂，搅拌条件下将溶剂蒸干，得到前驱体四。
本实施例得到的负极材料，其包括相互交缠的第一骨架、第二骨架和纳米硅，第一骨架为网络结构的硅酸镁锂材料，第二骨架为网络结构的碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
本实施例得到的负极材料，其包括硅酸镁锂材料、碳材料和纳米硅，硅酸镁锂材料为多孔结构，硅酸镁锂材料的孔道内填充碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
实施例8
本实施例与实施例1的方法步骤基本一致，其不同在于：(1)取500g的纳米二氧化硅，将其分散在10Kg的水溶液中，搅拌均匀后向其中加入40g的羧甲基纤维素钠，搅拌均匀后喷雾造粒，得到前驱体一。步骤(6)中，将前驱体五放置于化学气相沉积炉中，通入甲烷，在800℃沉积5h，沉积后的料粉碎、筛分得到负极材料。
本实施例得到的负极材料，其包括相互交缠的第一骨架、第二骨架和纳米硅，第一骨架为网络结构的硅酸镁锂材料，第二骨架为网络结构的碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
本实施例得到的负极材料，其包括硅酸镁锂材料、碳材料和纳米硅，硅酸镁锂材料为多孔结构，硅酸镁锂材料的孔道内填充碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
实施例9
本实施例与实施例1的方法步骤基本一致，其不同在于：(6)将前驱体五与沥青混合后，放置于热压烧成炉中，在30Mpa压下800℃煅烧3h，将煅烧后的料粉碎、筛分得到负极材料。
本实施例得到的负极材料，其包括相互交缠的第一骨架、第二骨架和纳米硅，第一骨架为网络结构的硅酸镁锂材料，第二骨架为网络结构的碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
本实施例得到的负极材料，其包括硅酸镁锂材料、碳材料和纳米硅，硅酸镁锂材料为多孔结构，硅酸镁锂材料的孔道内填充碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
实施例10
本实施例与实施例1的方法步骤基本一致，其不同在于：(6)将前驱体五与沥青混合后，放置于热压烧成炉中，在常压下800℃煅烧3h，将煅烧后的料粉碎、筛分得到负极材料。
本实施例得到的负极材料，其包括相互交缠的第一骨架、第二骨架和纳米硅，第一骨架为网络结构的硅酸镁锂材料，第二骨架为网络结构的碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
本实施例得到的负极材料，其包括硅酸镁锂材料、碳材料和纳米硅，硅酸镁锂材料为多孔结构，硅酸镁锂材料的孔道内填充碳材料；其中，硅酸镁锂材料基质内和表面分布有纳米硅。
表1 实施例1-10提供的负极材料
Figure PCTCN2022135736-appb-000001
Figure PCTCN2022135736-appb-000002
需要说明的是：Li xM ySiO 4材料的质量百分含量、纳米硅的质量百分含量和碳材料的质量百分含量之和接近且小于100％，其原因在于：在制备负极材料的时候，很有可能会含有一种或多种杂质，例如：未完全反应的硅氧化物、MgO、副产物MgSiO 4等中的一种或多种杂质。
其中，包覆碳层的厚度的测试方法为：切面SEM测试；
负极材料的比表面积的测试方法为：麦克比表面分析仪；
负极材料的D50的测试方法为：马尔文激光粒度仪3000；
Li xM ySiO 4材料的质量百分含量的测试方法为：全溶解成分分析法；
纳米硅的质量百分含量的测试方法为：X射线荧光分析法；
碳材料的质量百分含量的测试方法为：红外碳硫分析仪；
孔隙率的测试方法为：孔隙率通过压汞法测定。孔隙率至少测定三次，采用至少三次的算术平均作为测定结果；
骨架直径分布范围的测试方法：通过扫描电镜选取固定区域的不同点对骨架直径进行测量，得出骨架直径的分布范围。
对比例1
本对比例与实施例1的方法步骤基本一致，其不同在于：未进行步骤(4)，最终没有形成硅酸镁锂材料。
对比例2
本对比例与实施例1的方法步骤基本一致，其不同在于：未进行步骤(4)和步骤(6)，最终没有形成硅酸镁锂材料和碳材料。
对比例3
本对比例与实施例1的方法步骤基本一致，其不同在于：步骤(2)中，未添加熔融氯化钠，没有形成多孔结构或网络结构的骨架。
对比例4
本对比例与实施例1的方法步骤基本一致，其不同在于：未进行步骤(3)盐酸清洗反应，没有形成多孔结构的硅酸镁锂材料。
检测实施例1-实施例6、对比例1-对比例4提供的负极材料的性能如表2。
其中，将实施例1-实施例6以及对比例1-对比例4的复合负极材料与导电剂、粘结剂按质量百分比93:2:5在溶剂中混合，得到的混合浆料涂覆于铜箔集流体上，真空烘干、制得负极极片；然后将1mol/L的LiPF 6/EC+DMC+EMC(v/v＝1:1:1)电解液、SK(12μm)隔膜、外壳采用常规工艺装配CR2016扣式电池，电化学性能测试电流密度1C等于1000mAh/g。在0.1C条件下，测试材料容量和首效，在1C充放电条件下测试100次充放电循环保持率和100次充放电循环体积膨胀率。
表2 负极材料的性能
Figure PCTCN2022135736-appb-000003
从结合负极材料的制备方法、表1以及表2可以看出，本申请实施例提供的负极材料的首效较高，循环保持率较高，且体积膨胀系数较小。
其中，实施例1与对比例1对比可以看出，对比例1中未添加碳酸锂进行硅酸镁锂材料的制备，其首效较低，循环保持率较低，同时，由于没有硅酸镁锂材料的限制，负极材料的体积膨胀系数较高。
实施例1和对比例2对比可以看出，对比例2中未添加碳酸锂进行硅酸镁锂材料的制备，且未进行碳包覆，得到的负极材料虽然容量较高，但是，其体积膨胀系数很高，且循环保持率很小，首效也较低。
实施例1和对比例3对比可以看出，对比例3未添加熔融盐，在制备硅酸镁锂材料的时候，形成的孔道几乎没有，不容易形成碳材料与硅酸镁锂材料交缠的结构，得到的产品的循环保持率较低。
实施例1和对比例4对比可以看出，对比例4中，添加了熔融盐但没有进行盐酸酸洗，得到的负极材料中含有较多的熔融盐，不容易形成多孔结构的硅酸镁锂材料，其容量、首效和循环保持率都很低，体积膨胀系数也较高。
实施例1和实施例2对比可以看出，实施例1中，先烧成得到硅酸镁锂材料，再煅烧得到碳材料；实施例2中，一次热处理形成硅酸镁锂和碳材料，得到的负极材料的性能差别不大，说明通过烧成、煅烧分段制备，还是一次热处理制备，均可以使得到的负极材料的性能较好。
实施例1和实施例3对比可以看出，实施例1是加压包覆，实施例3是常压包覆，加压包覆得到的负极材料的性能相对更加优异。
实施例1和实施例4对比可以看出，实施例1中，使用沥青包覆的方式来制备碳材料，实施例4中，使用化学气相沉积法的方式制备碳材料，得到的负极材料的性能相当。
实施例1、实施例5和实施例6对比可以看出，实施例1中的Li xM ySiO 4的中的M金属为镁，实施例5中的M金属为铝，实施例6中的M金属为镁和铝的混合物，最终得到的负极材料的性能相当。
实施例1、实施例7和实施例8对比可以看出，实施例7的负极材料中第一骨架的直径过大，材料的克容量、首效下降，循环性能和膨胀性能无明显改善，这是因为第一骨架尺寸较大，导致锂离子较难在纳米硅颗粒中脱嵌，导致材料的容量及首效下降，实施例8的负极材料中第二骨架的直径过大，电性能下降，这是因为第二骨架的直径增大，材料中碳含量增加，碳材料的容量、首效都较纳米硅低，导致复合材料的容量下降、首效降低。
实施例1、实施例9和实施例10对比可以看出，实施例9的负极材料孔隙率过小，材料的膨胀变大，这是因为材料的孔隙率下降，充放电过程中缓解纳米硅体积膨胀的空间相对降低，导致材料的循环膨胀变大，实施例10的孔隙率过大，材料的比表面积变大，循环性能变差，这是因为空隙增大，电解液更容易渗透到材料内部，导致纳米硅与电解液的副反应增加，循环性能变差。
以上所描述的实施例是本申请一部分实施例，而不是全部的实施例。本申请的实施例的详细描述并非旨在限制要求保护的本申请的范围，而是仅仅表示本申请的选定实施例。基于本申请中的实施例，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，都属于本申请保护的范围。

Claims (10)

  1. 一种负极材料，其特征在于，所述负极材料包括复合材料，所述复合材料包括相互交缠的第一骨架、第二骨架及纳米硅，所述第一骨架包括Li xM ySiO 4材料，所述第二骨架包括碳材料，所述Li xM ySiO 4材料基质内或/和表面分布有所述纳米硅；其中，所述Li xM ySiO 4材料中，x、y的取值符合电荷平衡，M包括除Li以外的能够还原硅氧化物的金属元素。
  2. 根据权利要求1所述的负极材料，其特征在于，所述负极材料满足以下条件(1)-(14)中的至少一个：
    (1)所述负极材料还包括存在于所述复合材料表面的包覆碳层；
    (2)所述包覆碳层的厚度为5nm-80nm；
    (3)所述Li xM ySiO 4材料中，2≤x≤3.4，0.4≤y≤1；
    (4)M包括Mg或/和Al；
    (5)所述纳米硅的粒径为5nm-200nm；
    (6)所述碳材料包括软碳和硬碳中的一种或两种组合；
    (7)所述负极材料的比表面积为1m 2/g-3m 2/g；
    (8)所述负极材料的形状为球状颗粒，所述负极材料的颗粒平均粒径D50为5μm-30μm；
    (9)所述第二骨架的直径为10nm-500nm；
    (10)所述第一骨架的直径为10nm-400nm；
    (11)所述Li xM ySiO 4材料占所述负极材料的质量百分含量为5％-30％；
    (12)所述纳米硅占所述负极材料的质量百分含量为30％-60％；
    (13)所述碳材料占所述负极材料的质量百分含量为10％-65％；
    (14)所述包覆碳层包括所述碳材料。
  3. 一种负极材料，其特征在于，所述负极材料包括复合材料，所述复合材料包括Li xM ySiO 4材料、碳材料和纳米硅，所述Li xM ySiO 4材料为多孔结构，所述Li xM ySiO 4材料的孔道内填充有所述碳材料，所述Li xM ySiO 4材料基质内或/和表面分布有所述纳米硅；其中，所述Li xM ySiO 4材料中，x、y的取值符合电荷平衡，M为除Li以外的能够还原硅氧化物的金属。
  4. 根据权利要求3所述的负极材料，其特征在于，所述负极材料满足以下条件(15)-(27)中的至少一种：
    (15)所述负极材料存在于所述复合材料至少一部分表面的包覆碳层；
    (16)，所述包覆碳层的厚度为5nm-80nm；
    (17)所述Li xM ySiO 4材料中，2≤x≤3.4，0.4≤y≤1；
    (18)M包括Mg或/和Al；
    (19)所述纳米硅的粒径为5nm-200nm；
    (20)所述碳材料包括软碳和硬碳中的一种或两种组合；
    (21)所述负极材料的比表面积为1m 2/g-3m 2/g；
    (22)所述负极材料的形状为球状颗粒，所述负极材料的颗粒平均粒径D50为5μm-30μm；
    (23)所述Li xM ySiO 4材料的孔隙率为30％-46％；
    (24)所述Li xM ySiO 4材料占所述负极材料的质量百分含量为5％-30％；
    (25)所述纳米硅占所述负极材料的质量百分含量为30％-60％；
    (26)所述碳材料占所述负极材料的质量百分含量为10％-65％；
    (27)所述包覆碳层包括所述碳材料。
  5. 一种锂离子电池，其特征在于，包括权利要求1-4任一项所述的负极材料。
  6. 一种负极材料的制备方法，其特征在于，包括：
    形成基质内或/和表面分布有纳米硅且呈多孔结构或网络结构的Li xM ySiO 4材料；其中，所述Li xM ySiO 4材料中，M包括除Li以外的能够还原硅氧化物的金属元素；
    在所述Li xM ySiO 4材料的多孔结构的孔道中或网络结构的空隙中填充碳材料得到所述负极材料。
  7. 根据权利要求6所述的制备方法，其特征在于，所述制备方法包括：
    将具有网络结构或多孔结构的骨架材料与锂盐混合，然后进行烧成得到所述Li xM ySiO 4材料，其中，所述骨架材料包括纳米硅、负载于所述纳米硅表面的硅氧化物和金属M氧化物；及在所述Li xM ySiO 4材料的孔道或空隙中形成所述碳材料得到所述负极材料；
    或，将具有网络结构或多孔结构的骨架材料、锂盐与有机碳源混合，然后进行热处理得到所述负极材料，其中，所述骨架材料包括纳米硅、负载于所述纳米硅表面的硅氧化物和金属M氧化物。
  8. 根据权利要求7所述的制备方法，其特征在于，在所述Li xM ySiO 4材料的孔道或空隙中形成所述碳材料得到所述负极材料的步骤，包括：将所述Li xM ySiO 4材料与有机碳源混合并进行煅烧，使所述有机碳源碳化形成所述碳材料；或通过化学气相沉积法的方式在所述Li xM ySiO 4材料的孔道或空隙中形成所述碳材料；
    或，将具有网络结构或多孔结构的骨架材料、锂盐与有机碳源混合的步骤包括：将网络结构或多孔结构的所述骨架材料与所述锂盐混合，再与所述有机碳源混合。
  9. 根据权利要求7或8所述的制备方法，其特征在于，所述骨架材料的制备方法，包括：
    将硅氧化物和粘结剂混合后进行造粒，得到前驱体一；
    将所述前驱体一、金属M粉和熔融盐混合，并进行热反应使得至少部分所述硅氧化物被还原成纳米硅，得到前驱体二；
    将所述前驱体二进行酸洗去掉部分金属M氧化物，以形成多孔结构或网络结构的所述骨架材料。
  10. 根据权利要求9所述的制备方法，其特征在于，所述制备方法满足以下条件(28)-(32)中的至少一个：
    (28)将硅氧化物和粘结剂分散在溶液中，喷雾造粒得到前驱体一；
    (29)所述硅氧化物与所述粘结剂的质量比为(40-100):1；
    (30)所述前驱体一、所述熔融盐和所述金属M粉的质量比依次为1:(3-8):(0.5-1.5)；
    (31)所述金属M粉包括Mg粉、Al粉和MgAl合金粉中的一种或多种组合；
    (32)所述骨架材料、可溶性锂盐和水混合，搅拌均匀以后干燥。
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2025028414A1 (ja) * 2023-08-02 2025-02-06 パナソニックＩｐマネジメント株式会社 負極活物質および電池

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN120878747A (zh) * 2024-04-30 2025-10-31 宁德时代新能源科技股份有限公司 负极极片、二次电池、用电装置、硬碳材料及其制备方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013125648A (ja) * 2011-12-14 2013-06-24 Taiheiyo Cement Corp リチウムイオン電池用正極活物質及びリチウムイオン電池
CN107534136A (zh) * 2015-03-02 2018-01-02 Eo细胞有限公司 具有嵌入于硅：硅锂硅酸盐复合物基体中的纳米硅颗粒的硅‑氧化硅‑锂复合物材料及其制造方法
CN111357140A (zh) * 2017-12-28 2020-06-30 松下知识产权经营株式会社 非水电解质二次电池用负极活性物质
CN113195406A (zh) * 2018-12-21 2021-07-30 松下知识产权经营株式会社 二次电池用负极活性物质及二次电池
CN113659122A (zh) * 2021-08-16 2021-11-16 四川金汇能新材料股份有限公司 一种硅碳负极材料、制备方法、应用

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5406799B2 (ja) 2010-07-29 2014-02-05 信越化学工業株式会社 非水電解質二次電池用負極材とその製造方法及びリチウムイオン二次電池
KR101960855B1 (ko) 2017-03-20 2019-03-21 대주전자재료 주식회사 리튬 이차전지 음극재용 실리콘 복합산화물 및 이의 제조방법
CN111357135B (zh) 2017-11-29 2023-10-13 松下知识产权经营株式会社 锂离子电池
WO2019151814A1 (ko) * 2018-01-31 2019-08-08 주식회사 엘지화학 음극 활물질, 이를 포함하는 음극 및 리튬 이차전지
CN115552676A (zh) * 2020-03-30 2022-12-30 松下知识产权经营株式会社 二次电池
CN115917787A (zh) * 2020-05-29 2023-04-04 松下知识产权经营株式会社 二次电池用负极活性物质及二次电池
CN112331854A (zh) 2020-10-30 2021-02-05 浙江锂宸新材料科技有限公司 一种硅酸镁锂预锂化氧化亚硅负极材料及其制备方法和应用

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013125648A (ja) * 2011-12-14 2013-06-24 Taiheiyo Cement Corp リチウムイオン電池用正極活物質及びリチウムイオン電池
CN107534136A (zh) * 2015-03-02 2018-01-02 Eo细胞有限公司 具有嵌入于硅：硅锂硅酸盐复合物基体中的纳米硅颗粒的硅‑氧化硅‑锂复合物材料及其制造方法
CN111357140A (zh) * 2017-12-28 2020-06-30 松下知识产权经营株式会社 非水电解质二次电池用负极活性物质
CN113195406A (zh) * 2018-12-21 2021-07-30 松下知识产权经营株式会社 二次电池用负极活性物质及二次电池
CN113659122A (zh) * 2021-08-16 2021-11-16 四川金汇能新材料股份有限公司 一种硅碳负极材料、制备方法、应用

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4273965A4 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2025028414A1 (ja) * 2023-08-02 2025-02-06 パナソニックＩｐマネジメント株式会社 負極活物質および電池

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