WO2022016951A1 - Silicon-based negative electrode material, negative electrode, and lithium-ion battery and preparation method therefor - Google Patents

Silicon-based negative electrode material, negative electrode, and lithium-ion battery and preparation method therefor Download PDF

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WO2022016951A1
WO2022016951A1 PCT/CN2021/091857 CN2021091857W WO2022016951A1 WO 2022016951 A1 WO2022016951 A1 WO 2022016951A1 CN 2021091857 W CN2021091857 W CN 2021091857W WO 2022016951 A1 WO2022016951 A1 WO 2022016951A1
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silicon
negative electrode
sio
preparing
electrode material
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PCT/CN2021/091857
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French (fr)
Chinese (zh)
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庞春雷
石晓太
汪静伟
任建国
贺雪琴
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贝特瑞新材料集团股份有限公司
惠州市鼎元新能源科技有限公司
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—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 disclosure belongs to the field of energy storage materials and electrochemistry, and in particular relates to a silicon-based negative electrode material, a negative electrode, a lithium ion battery and a preparation method thereof.
  • lithium-ion batteries With the expansion of the application field of lithium-ion batteries, lithium-ion batteries have become a hot spot of research work. As an important part of lithium-ion batteries, anode materials affect the specific energy and cycle life of lithium-ion batteries, and have always been the focus of lithium-ion battery research.
  • the traditional graphite-based negative electrode material has a low capacity for storing lithium ions (theoretically 372mAh/g), which leads to the problem that the overall capacity of the battery made with it is not high.
  • the global automobile industry is transforming from internal combustion engines to electric vehicles, so the requirements for battery energy density are getting higher and higher, so lithium-ion batteries made of traditional graphite anode materials can no longer meet the needs of electric vehicles.
  • the development of new energy lithium-ion battery anode materials with high energy density and high power density is imminent.
  • Silicon has the highest theoretical specific capacity (4200mAh/g) and lower discharge potential, and is the most promising anode material for next-generation lithium-ion batteries.
  • the large volume expansion (up to 300%) of silicon during charge and discharge cycles can lead to anode cracking and pulverization, which limits its commercial application.
  • silicon oxide is a negative electrode material with higher specific capacity, and its volume change is smaller during charge and discharge than silicon. In addition, it also has the advantages of low working voltage and wide source of raw materials.
  • silicon oxide can alleviate its own volume expansion, due to the generation of irreversible Li 2 O during the first cycle, the consumption of Li in the cathode material is increased, and the irreversible capacity is increased, resulting in a low first Coulomb efficiency.
  • the commonly used method is to introduce a lithium source into the silicon oxide.
  • the preparation process of the material and the electrode has a greater risk, resulting in Its practical application is difficult.
  • due to the complex process, high cost, and the use of highly corrosive and highly toxic raw materials its industrial application is hindered.
  • the present disclosure provides a silicon-based negative electrode material, and the silicon-based negative electrode material includes:
  • Core said core comprising a silicate of silicon, silicon oxide and M; and the formula of the silicon oxide is SiO x, 0 ⁇ x ⁇ 2 , M is a metal; and
  • a carbon coating, the carbon coating is formed on the surface of the inner core, and the thickness of the carbon coating is 50 nm-200 nm.
  • the thickness of the carbon coating is 100 nm-200 nm.
  • the M includes, but is not limited to, any one or a combination of at least two of Li, Mg, Al, Zn, Ca, Na, and Ti.
  • the M further includes Fe or a combination of Fe and any one or at least two of Li, Mg, Al, Zn, Ca, Na, and Ti.
  • the mass fraction of the M element is between 1-30%.
  • the average particle size D50 of the silicon-based negative electrode material is 0.5 ⁇ m-40 ⁇ m.
  • the silicon-based negative electrode material has a specific surface area of 0.5 m 2 /g to 40 m 2 /g.
  • the present disclosure provides a preparation method of the silicon-based negative electrode material, and the method includes the following steps:
  • Carbon coating treatment is performed on the silicon composite to form a carbon film with a thickness of 50 nm to 200 nm on the surface of the silicon composite to obtain a silicon-based negative electrode material.
  • the present disclosure provides a method for preparing the silicon-based negative electrode material, and the method includes the following steps:
  • Carbon coating treatment is performed on the silicon composite to form a carbon film with a thickness of 50 nm to 200 nm on the surface of the silicon composite to obtain a silicon-based negative electrode material.
  • the preparation method of the SiO steam and the M elemental steam includes the following steps: regulating and controlling the raw materials containing SiO and/or preparing the SiO and the M element and/or the raw material for preparing the M element.
  • the temperature and pressure of the reaction environment are used to obtain the SiO vapor and the M elemental vapor.
  • the raw materials for preparing SiO include a mixture of Si and SiO 2 in a mass ratio of 1:1.5-1:2.5.
  • the raw materials for preparing the elemental M include a mixture of the materials used for preparing the elemental M.
  • the reaction environment is a vacuum environment.
  • the specific operation of the reaction environment for forming the SiO-containing and/or SiO-preparing raw materials and the M elemental substance and/or the M elemental-preparing raw materials is: placing the SiO and/or the SiO-preparing raw materials in a vacuum in the furnace.
  • the step of placing the SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO in a vacuum furnace Close to one end of the furnace tail, place the M element and/or the raw material for preparing M element in the end of the vacuum furnace close to the furnace mouth.
  • the step of placing the SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO in a vacuum furnace close to the furnace mouth At one end, the M element and/or the raw material for preparing M element is placed at the end of the vacuum furnace close to the furnace tail.
  • the step of placing SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO with the M element and/or The raw materials for preparing M elemental substance are mixed and placed in a vacuum furnace.
  • the temperature in the step of regulating the temperature and pressure of the reaction environment containing SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M is 1200°C-1600°C, and the pressure It is 0.1Pa-500Pa.
  • the method further includes performing the following step after the step of obtaining the silicon composite and before the carbon coating treatment step on the silicon composite: At least one of crushing, classifying and firing the composite.
  • the method further includes performing the following steps after the step of obtaining the silicon composite to condense into a solid phase material, and before the carbon coating treatment step on the silicon composite solid phase material: the step is according to the scheme Any one of I, Scheme II or Scheme III is carried out.
  • the scheme I is: pulverizing, classifying and firing the silicon composite in sequence
  • the scheme II is: pulverizing, sintering and classifying the silicon composite in sequence
  • the scheme III is: firing, pulverizing and classifying the silicon composite in sequence.
  • the carbon coating method in the step of carbon coating treatment on the silicon composite includes: any one of gas phase coating, liquid phase coating and solid phase coating or at least combination of the two.
  • the carbon coating in the step of carbon coating treatment on the silicon composite is performed by gas-phase coating. composite anode material.
  • the carbon coating in the step of carbon coating treatment on the silicon composite is performed by means of solid phase coating or liquid phase coating, by controlling the mass and firing temperature of the carbon-containing material mixed in The thickness of the carbon coating is controlled to obtain a composite negative electrode material.
  • the method includes the following steps:
  • the M steam and the SiO steam are uniformly mixed in a mixing device placed in a vacuum furnace, and then cooled and condensed to obtain a solid-phase M and SiO mixed silicon composite;
  • the powder material is coated with carbon, so that the thickness of the carbon film on the surface of the silicon composite is between 50 nm and 200 nm to obtain a silicon-based negative electrode material.
  • the present disclosure provides a negative electrode comprising the silicon-based negative electrode material.
  • the present disclosure provides a lithium ion secondary battery including the silicon-based negative electrode material.
  • Fig. 1 is the electron microscope photograph of the particle cross section of silicon composite negative electrode material in embodiment 1;
  • Fig. 2 is the electron microscope photograph of the particle cross section of silicon composite negative electrode material among the embodiment 2;
  • Fig. 3 is the electron microscope photograph of the particle cross section of silicon composite negative electrode material in Comparative Example 1;
  • Fig. 4 is the electron microscope photograph of the particle cross section of silicon composite negative electrode material in Comparative Example 2;
  • Fig. 5 is the electron microscope photograph of the particle cross section of silicon composite negative electrode material in Comparative Example 3;
  • Fig. 6 is the electron microscope photograph of the particle cross section of silicon composite negative electrode material in Comparative Example 4.
  • FIG. 7 is a schematic structural diagram of a silicon-based negative electrode material provided by some embodiments of the present disclosure.
  • FIG. 8 is a schematic diagram of a cathode structure provided by some embodiments of the present disclosure.
  • FIG. 9 is a schematic diagram of a battery provided by some embodiments of the present disclosure.
  • An embodiment provides a silicon-based negative electrode material, a preparation method thereof, and a lithium ion secondary battery.
  • the preparation process is simple and the cost is low, and the obtained silicon-based negative electrode material has the advantages of high initial charge-discharge efficiency and good cycle performance when applied to a lithium ion secondary battery.
  • some embodiments provide a silicon-based negative electrode material 100 , and the silicon-based negative electrode material 100 includes:
  • Core 120, the core 120 silicates include silicon, silicon oxide and M; and the chemical formula of the silicon oxide is SiO x, 0 ⁇ x ⁇ 2 , M is a metal; and a carbon film 140, the The carbon coating 140 is formed on the surface of the inner core 120, and the thickness of the carbon coating 140 is 50 nm-200 nm.
  • the chemical formula of the silicon oxide SiO x, x is equal to 2, that is, when silica, which is a lower electrode active; X is greater than 2, and the other was a mixture of silica compound, an electrode active Also lower.
  • the thickness of the carbon coating 140 is, for example, 50 nm, 60 nm, 80 nm, 90 nm, 100 nm, 110 nm, 125 nm, 135 nm, 150 nm, 170 nm, 180 nm, or 200 nm, etc.
  • x is, for example, 0.3, 0.5, 1 , 1.2, 1.5, 1.7, 1.9, etc.
  • the thickness of the carbon coating 140 is 50 nm-100 nm, 100 nm-130 nm, 130 nm-160 nm, or 100 nm-200 nm.
  • silicon, silicon oxide and silicate are uniformly distributed in the inner core 120, and the surface of the inner core 120 is uniformly covered with a carbon film 140 with a thickness between 50 nm and 200 nm, In at least some embodiments, the thickness of the carbon coating 140 is between 100 nm-200 nm for better electrochemical performance.
  • a silicon-based negative electrode material with a carbon coating thickness between 50 nm and 200 nm is obtained.
  • M element doped silicon composites can be prepared by mixing SiO vapor and M vapor and cooling the resulting deposit in a vacuum environment. Through steam mixing, atomic-level homogeneous mixing of SiO and M elements can be achieved. However, the conductivity of the composite is extremely poor, and its capacity cannot be effectively exerted when it is directly used as a negative electrode material.
  • the solution adopted by the public is to cover a layer of carbon film 140 on the surface of the material, to improve the conductivity of the silicon composite to ensure the performance of the capacity, and through a large number of experiments, it is found that the thickness of the carbon layer is between 50nm-200nm silicon-based negative electrode When the material is 100, defect-free coating on the surface of the composite can be effectively achieved, and the capacity efficiency and cycle performance of the electrode material are optimal.
  • the thickness of the carbon layer is less than 50 nm, the surface of the silicon composite particles cannot be completely covered by the carbon layer, and there are still many exposed parts.
  • the exposed parts will In direct contact with the electrolyte 260, an unstable SEI film is repeatedly generated, resulting in excessive consumption of the electrolyte 260, resulting in decreased cycle performance; on the other hand, the exposed part has extremely poor conductivity, and the active material in this part cannot be effectively embedded. The delithiation reaction will cause a decrease in capacity.
  • the carbon layer on the surface of the silicon composite particle is too thick.
  • the thick carbon layer is easily cracked by the internal stress of the particle during repeated charge and discharge processes. , resulting in the direct contact of the silicon composite with the electrolyte 260 and the deactivation of the exposed site due to loss of electrical contact, resulting in a reduction in material performance.
  • the carbon layer thickness of the silicon composite negative electrode material is limited to between 50 nm and 200 nm, and the silicon-based negative electrode material 100 with the carbon layer thickness within this range, wherein the surface of the silicon composite particles can be completely covered, and The thickness is controlled within the optimum range, which can effectively buffer the volume expansion of the composite during charging and discharging.
  • a carbon layer of suitable thickness also has a positive effect on the volume control of the material. Therefore, the capacity efficiency and cycle performance of the silicon composite can be significantly improved.
  • the silicon-based anode material 100 with a carbon layer thickness of 100 nm has a reversible capacity close to 1400 mAh/g, a first-week Coulombic efficiency of 90%, and a 50-cycle cycle retention rate of more than 90%.
  • the M includes, but is not limited to, any one or a combination of at least two of Li, Mg, Al, Zn, Ca, Na, and Ti.
  • the M further includes Fe or a combination of Fe and any one or at least two of Li, Mg, Al, Zn, Ca, Na, and Ti.
  • the mass fraction of the M element ranges from 1-30%, 1-7%, 6%-8%, 8%- 12%, 12%-20% or between 20%-30%, e.g. 1%, 3%, 5%, 6%, 8%, 10%, 13%, 16%, 20%, 22.5%, 25% , 28% or 30%, etc.
  • the mass fraction of M element within the above range can avoid huge volume expansion during the charge-discharge cycle, thereby preventing capacity loss and performance degradation; at the same time, it can effectively further improve the first-week Coulomb efficiency of the composite material.
  • the mass fraction of M element is greater than 30%, M will react violently with SiO vapor after cooling and deposition, and generate Si particles with larger size. The surface peels off, resulting in capacity loss and performance degradation; when the mass fraction of M element is less than 1%, too little M reacts with SiO, and the amount of Si generated is correspondingly small, which cannot effectively improve the first week Coulomb efficiency of the composite material , has no practical significance.
  • the average particle size D50 of the silicon-based negative electrode material 100 is 0.5 ⁇ m-40 ⁇ m, such as 0.5 ⁇ m, 1 ⁇ m, 3 ⁇ m, 5 ⁇ m, 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 25 ⁇ m, 30 ⁇ m, 35 ⁇ m, or 40 ⁇ m.
  • the utilization rate of the electrolyte 260 in the battery can be improved, and the cycle performance of the battery can be further improved in conjunction with the above technical features.
  • the average particle size of the silicon-based negative electrode material is too large, it is not conducive to the manufacture of the electrode material process. If the particle size is too small, the specific surface area is too large. During the charging and discharging process, a side reaction will occur with the electrolyte 260, which will further consume the electrolysis. Liquid 260, which reduces the cycle performance of the electrode and affects the battery life.
  • the specific surface area of the silicon-based negative electrode material 100 is 0.5m 2 /g-40m 2 /g, such as 0.5m 2 /g, 2m 2 /g, 5m 2 /g, 8m 2 /g, 12m 2 /g, 15m 2 /g, 20m 2 /g, 25m 2 /g, 30m 2 /g, 35m 2 /g or 40m 2 /g, etc.
  • An embodiment provides the preparation method of the silicon-based negative electrode material 100, and the method includes the following steps:
  • a carbon coating treatment is performed on the silicon composite to form a carbon coating 140 with a thickness of 50 nm-200 nm on the surface of the silicon composite to obtain a silicon-based negative electrode material 100 .
  • the method includes the steps of:
  • a carbon coating treatment is performed on the silicon composite to form a carbon coating 140 with a thickness of 50 nm-200 nm on the surface of the silicon composite to obtain a silicon-based negative electrode material 100 .
  • the silicon-based negative electrode material 100 with the thickness of the carbon coating 140 between 50 nm and 200 nm is obtained.
  • the preparation method of the SiO steam and the M elemental steam includes the following steps: regulating and controlling the raw materials containing SiO and/or preparing the SiO and the M element and/or the raw material for preparing the M element.
  • the temperature and pressure of the reaction environment are used to obtain the SiO vapor and the M elemental vapor.
  • the raw materials for preparing SiO include a mixture of Si and SiO 2 mixed in a mass ratio of 1:1.5-1:2.5, for example, a mass ratio of 1:1.5, 1:1.7, 1:1.9, 1:2.0, 1:2.2, 1:2.3, 1:2.4, 1:2.5.
  • the raw material for preparing M elemental substance includes a mixture after the substances used for preparing M elemental substance are mixed.
  • the reaction environment is a vacuum environment.
  • the specific operation of the reaction environment for forming the SiO-containing and/or SiO-preparing raw materials and the M elemental substance and/or the M elemental-preparing raw materials is: placing the SiO and/or the SiO-preparing raw materials in a vacuum in the furnace.
  • the elemental M and/or the raw materials for preparing the elemental M are placed in a vacuum furnace.
  • each raw material is mixed according to a stoichiometric ratio to completely generate the product silicon-based negative electrode material 100 .
  • the condensation can be achieved by the following methods: a mixing device and a condensing device are arranged at one end of the reactor, the SiO steam and the M steam are uniformly mixed when passing through the mixing device, and then the condensing device is Condensed into a solid phase material.
  • the step of placing the SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO in a vacuum furnace Close to one end of the furnace tail, place the M element and/or the raw material for preparing M element in the end of the vacuum furnace close to the furnace mouth.
  • the step of placing the SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO in a vacuum furnace close to the furnace mouth At one end, the M element and/or the raw material for preparing M element is placed at the end of the vacuum furnace close to the furnace tail.
  • the step of placing the SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO with the M element and/or The raw materials for preparing M elemental substance are mixed and placed in a vacuum furnace.
  • the raw materials for preparing the elemental M include a mixture of the materials used for preparing the elemental M.
  • M is Ca
  • the raw material of M can be a mixture of dolomite powder and ferrosilicon powder.
  • M is Ca
  • the raw material of M is a mixture of limestone powder and aluminum powder.
  • M is Ca
  • the raw material of M is metallic calcium bulk.
  • M is Mg
  • the raw material of M is magnesium powder
  • the temperature in the step of regulating the temperature and pressure of the reaction environment containing SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M is 1200°C-1600°C, such as 1200°C , 1250°C, 1300°C, 1400°C, 1450°C, 1500°C or 1600°C, etc.
  • the pressure is 0.1Pa-500Pa, such as 0.1Pa, 0.5Pa, 3Pa, 10Pa, 20Pa, 35Pa, 60Pa, 80Pa, 100Pa, 150Pa, 200Pa, 250Pa, 300Pa, 350Pa, 400Pa or 500Pa, etc.
  • the silicon oxide and the dopant M element can be made to generate a uniform compound at the atomic level in a relatively stable manner. If the temperature is too low, it is easy to evaporate only a single component. If the temperature is too high, there will be problems of uneven evaporation and mismatch of the mixing amount of elements.
  • the method further includes performing the following step after the step of obtaining the silicon composite and before the carbon coating treatment step on the silicon composite: At least one of crushing, classifying and firing the composite.
  • the method further includes performing the following steps after the step of obtaining the silicon composite to condense into a solid phase material, and before the carbon coating treatment step on the silicon composite solid phase material: the step is according to the scheme Any one of I, Scheme II or Scheme III is carried out.
  • the scheme I is: pulverizing, classifying and firing the silicon composite in sequence
  • the scheme II is: pulverizing, sintering and classifying the silicon composite in sequence
  • the scheme III is: firing, pulverizing and classifying the silicon composite in sequence.
  • the carbon coating method in the step of carbon coating treatment on the silicon composite includes: any one of gas phase coating, liquid phase coating and solid phase coating or at least combination of the two.
  • the carbon coating in the step of carbon coating treatment on the silicon composite is performed by gas-phase coating, and the thickness of the carbon coating 140 is controlled by controlling the flow rate and passage time of the carbon-containing gas, A composite negative electrode material is obtained.
  • the specific method of control is the existing technology, and those skilled in the art can operate with reference to the existing technology. It is not a conventional choice to control the thickness of the carbon layer between 50nm and 200nm by controlling the above parameters, and it has achieved an unexpected improvement cycle. performance and other electrochemical properties.
  • the carbon coating in the step of carbon coating treatment on the silicon composite is performed by means of solid phase coating or liquid phase coating, by controlling the mass and firing temperature of the carbon-containing material mixed in The thickness of the carbon coating 140 is controlled to obtain a composite negative electrode material.
  • the specific method of control is the existing technology, and those skilled in the art can operate with reference to the existing technology. It is not a conventional choice to control the thickness of the carbon layer between 50nm and 200nm by controlling the above parameters, and it has achieved an unexpected improvement cycle. performance and other electrochemical properties.
  • the method includes the following steps:
  • M steam and SiO steam are generated in the environment of 1200°C-1600°C and 0.5Pa-500Pa;
  • the M steam and the SiO steam are uniformly mixed in a mixing device placed in a vacuum furnace, and then cooled and condensed to obtain a solid-phase M and SiO mixed silicon composite;
  • the powder material is coated with carbon, so that the thickness of the carbon film 140 on the surface of the silicon composite is between 50 nm and 200 nm to obtain the silicon-based negative electrode material 100 .
  • the silicon-based negative electrode material 100 may be used as a negative electrode active material, such as a negative electrode active material in the lithium ion battery 200 .
  • An embodiment provides a negative electrode material, and the negative electrode material includes the above-mentioned silicon-based negative electrode material 100 .
  • the negative electrode material includes a silicon-based negative electrode material 100, a conductive agent, and a binder.
  • the negative electrode material further comprises graphite.
  • the mass ratio of the silicon-based negative electrode material 100 to graphite is 1:(6-12).
  • An embodiment provides a method for preparing a negative electrode material, including: mixing a silicon-based negative electrode material 100 with a conductive agent and a binder.
  • an embodiment provides a negative electrode 240 including a silicon-based negative electrode material 100 .
  • the negative electrode includes: a negative electrode current collector 242 and a negative electrode material layer 244 on the negative electrode current collector 242 , wherein the negative electrode material layer 244 includes the above-mentioned negative electrode material.
  • An embodiment provides a method for preparing the negative electrode 240 , including: coating a slurry including a negative electrode material on the negative electrode current collector 242 .
  • a negative electrode comprising: a negative electrode current collector 242 and a negative electrode active material layer 244 on the negative electrode current collector 242, wherein the negative electrode active material layer 244 comprises the above-described silicon-based negative electrode material 100.
  • the anode active material layer 244 further includes a conductive agent and a binder.
  • the anode active material layer 244 further includes graphite.
  • the mass ratio of the silicon-based negative electrode material 100, the conductive agent and the binder is (70-95):(2-15):(4-10). In some embodiments, the mass ratio of silicon-based anode material 100 to graphite is 1:(6-12).
  • a method of preparing a negative electrode 240 comprising: applying a slurry including a silicon-based negative electrode material 100 on the negative electrode current collector 242 , so that the negative electrode current collector 242 is forming a negative electrode active material layer 244 thereon; and drying the negative electrode active material layer 244 .
  • drying may be vacuum drying.
  • the total solids content of the slurry is between 30% and 60%. In some embodiments, the total solid content of the silicon-based negative electrode material 100, the conductive agent and the binder in the slurry is 30%-60%. In some embodiments, the total solid content of the silicon-based negative electrode material 100, the conductive agent, the binder and the graphite in the slurry is 30%-60%.
  • each component in the negative electrode active material layer 244 eg, the silicon-based negative electrode material 100, the conductive agent and the binder
  • is mixed and optionally graphite
  • the anode current collector 242 may be a metal.
  • the negative electrode current collector 242 includes, but is not limited to, one of a copper foil current collector and an aluminum foil current collector.
  • the slurry may contain solvent.
  • the solvent includes, but is not limited to, water.
  • the binder can improve the bonding properties of the anode active material particles with each other and with the current collector 242 .
  • the binder includes at least one of a non-aqueous binder or an aqueous binder.
  • Non-aqueous binders include, but are not limited to, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride, polyvinylidene fluoride, polyvinylidene At least one of ethylene, polypropylene, polyamideimide, or polyimide.
  • Aqueous binders include, but are not limited to, at least one of rubber-based binders or polymeric resin binders.
  • Conductive agents can improve the conductivity of electrodes.
  • Conductive agents include but are not limited to high conductivity materials such as gold, copper, nickel, aluminum, silver, and/or similar metal powders or metal fibers and/or similar metal-based materials; or natural graphite, artificial graphite , carbon black, acetylene black, Ketjen black, carbon fiber and/or similar carbon-based materials; or polyphenylene derivatives and/or similar conductive polymers; and/or mixtures thereof.
  • One embodiment provides a lithium-ion battery 200 including the above-described silicon-based negative electrode material 100 .
  • lithium-ion battery 200 includes:
  • the negative electrode 240 includes a negative electrode current collector 242 and a negative electrode active material layer 244 disposed on the negative electrode current collector 242 , and the negative electrode active material layer 244 includes the silicon-based negative electrode material 100 .
  • the lithium-ion battery 200 may include a separator 280 disposed between the positive electrode 220 and the negative electrode 240 .
  • the membrane 280 may be a polymeric microporous membrane, such as a polypropylene microporous membrane. Septum 280 may be commercially available.
  • the lithium-ion battery 200 may include a housing 290 .
  • the positive electrode 220 , the negative electrode 240 , the separator 280 , and the electrolyte 260 may be accommodated in the case 290 .
  • the lithium ion battery may be a cylindrical battery, a prismatic battery, or a coin cell battery.
  • Lithium-ion batteries can be rigid case batteries or pouch batteries.
  • the positive electrode 220 may include a positive electrode current collector and a positive electrode active material layer disposed on the positive electrode current collector.
  • the positive electrode active material layer includes a positive electrode active material capable of reversibly intercalating and deintercalating lithium ions, and examples of the positive electrode active material include, but are not limited to, one of LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , and lithium-transition metal oxides. kind.
  • the electrolyte 260 includes, but is not limited to, a non-aqueous organic solvent, such as at least one of carbonates, esters, ethers, or ketones.
  • carbonates include, but are not limited to, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC) , at least one of methyl ethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC) or butylene carbonate (BC).
  • Esters include but are not limited to butyrolactone (BL), decanolide, valerolactone (BL), mevalonolactone, caprolactone (BC), methyl acetate, ethyl acetate or n-propyl acetate at least one of.
  • Ethers include, but are not limited to, may include dibutyl ether.
  • Ketones include, but are not limited to, polymethyl vinyl ketone.
  • a silicon-based negative electrode material 100 with a carbon film 140 having a thickness of 50 nm-200 nm is obtained, so as to improve the conductivity of the silicon composite, and a carbon film 140 with a suitable thickness coats the silicon composite It can significantly improve the capacity efficiency and cycle performance of the silicon composite.
  • the other methods only disclose the method of carbon coating the composite and control the degree of carbon coating by controlling the mass fraction of the contained carbon element.
  • the appropriate coating amount and the mass fraction of carbon are different. For example, for a material with a relatively large area, covering the surface of the material uniformly and completely with a carbon layer requires a lot of carbon. At this time, only the mass fraction of carbon is controlled, which will inevitably lead to some particles or particles. Some locations cannot be covered by the carbon layer or the carbon layer is too thick.
  • the degree of carbon coating is controlled by controlling the thickness of the carbon coating layer, which can effectively achieve defect-free coating on the surface of the composite, and the capacity efficiency and cycle performance of the electrode material are more excellent.
  • the preparation of the embodiment is not only simple in process and low in cost, but also has the advantages of high initial charge-discharge efficiency and good cycle performance when the obtained silicon-based negative electrode material 100 is applied to the lithium ion secondary battery 200 .
  • This embodiment provides a silicon-based negative electrode material 100 and a preparation method thereof.
  • the silicon-based negative electrode material 100 includes an inner core 120 and a carbon coating 140 covering the surface of the inner core 120 , and the inner core 120 includes silicon, silicon oxide and silicon.
  • Magnesium oxide, the thickness of the carbon film 140 is 100 nm, and the mass fraction of Mg element is 15% based on the total mass of the negative electrode material as 100%.
  • the silicon-based negative electrode material 100 is prepared by the following method:
  • a collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite (including Si , SiO and magnesium silicate), after the reaction, the equipment was cooled and 11 kg of product was collected.
  • the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
  • This embodiment provides a silicon-based negative electrode material 100 and a preparation method thereof.
  • the silicon-based negative electrode material 100 includes an inner core 120 and a carbon coating 140 covering the surface of the inner core 120 , and the inner core 120 includes silicon, silicon oxide and silicon.
  • Magnesium oxide, the thickness of the carbon coating 140 is 200 nm, and the mass fraction of Mg element is 15% based on the total mass of the negative electrode material as 100%.
  • the silicon-based negative electrode material 100 is prepared by the following method:
  • a collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite (including Si , SiO and magnesium silicate), after the reaction, the equipment was cooled and 11 kg of product was collected.
  • the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
  • This embodiment provides a silicon-based negative electrode material 100 and a preparation method thereof.
  • the silicon-based negative electrode material 100 includes an inner core 120 and a carbon coating 140 covering the surface of the inner core 120 , and the inner core 120 includes silicon, silicon oxide and silicon.
  • Magnesium oxide, the thickness of the carbon coating 140 is 200 nm, and the mass fraction of Mg element is 9.5% based on the total mass of the negative electrode material as 100%.
  • the silicon-based negative electrode material 100 is prepared by the following method:
  • a collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite (including Si , SiO and magnesium silicate), after the reaction, the equipment was cooled and 10kg of product was collected.
  • the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
  • This embodiment provides a silicon-based negative electrode material 100 and a preparation method thereof.
  • the silicon-based negative electrode material 100 includes an inner core 120 and a carbon coating 140 covering the surface of the inner core 120 , and the inner core 120 includes silicon, silicon oxide and silicon.
  • calcium acid, the thickness of the carbon coating 140 is 160 nm, and the mass fraction of Ca element is 8% based on the total mass of the negative electrode material as 100%.
  • the silicon-based negative electrode material 100 is prepared by the following method:
  • a collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Ca vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite (including Si , SiO and calcium silicate), after the reaction, the equipment was cooled and 8.8kg of product was collected.
  • the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
  • This embodiment provides a silicon-based negative electrode material 100 and a preparation method thereof.
  • the silicon-based negative electrode material 100 includes an inner core 120 and a carbon coating 140 covering the surface of the inner core 120 , and the inner core 120 includes silicon, silicon oxide and silicon. Calcium acid, the thickness of the carbon coating 140 is 130 nm, and the mass fraction of Ca element is 9% based on the total mass of the negative electrode material as 100%.
  • the silicon-based negative electrode material 100 is prepared by the following method:
  • a collection device is installed in the condensation chamber, heated to 1350 ° C under vacuum conditions to generate SiO vapor and Ca vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite (including Si , SiO and calcium silicate), after the reaction, the equipment was cooled and 9.6kg of product was collected.
  • the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
  • This embodiment provides a silicon-based negative electrode material 100 and a preparation method thereof.
  • the silicon-based negative electrode material 100 includes an inner core 120 and a carbon coating 140 covering the surface of the inner core 120 , and the inner core 120 includes silicon, silicon oxide and silicon.
  • Magnesium oxide, the thickness of the carbon coating 140 is 50 nm, and the mass fraction of Mg element is 15% based on the total mass of the negative electrode material as 100%.
  • the silicon-based negative material 100 is prepared by the following method:
  • a collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite (including Si , SiO and magnesium silicate), after the reaction, the equipment was cooled and 11 kg of product was collected.
  • silicon compound Except in the synthesis of silicon compound, (1) take 5kg silicon powder (its chemical composition is Si), 10kg silicon micropowder (its chemical composition is SiO 2 ), use a VC mixer to mix for 30min to obtain SiO raw materials, put into vacuum One end of the furnace reaction chamber close to the furnace mouth;
  • a collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite, and the reaction is completed. The equipment was then cooled and 11 kg of product was collected.
  • a collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite, and the reaction is completed. The equipment was then cooled and 11 kg of product was collected.
  • the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
  • a collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite, and the reaction is completed. The equipment was then cooled and 11 kg of product was collected.
  • the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
  • a collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite, and the reaction is completed. The equipment was then cooled and 11 kg of product was collected.
  • the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
  • the silicon-based negative electrode material in this comparative example includes an inner core 120 and a carbon film covering the surface of the inner core 120.
  • the inner core 120 includes silicon, silicon oxide and magnesium silicate, the thickness of the carbon film is 100 nm, and the total mass of the negative electrode material is 100 nm. %, the mass fraction of Mg element is 0.5%.
  • a collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite, and the reaction is completed. The equipment was then cooled and 9.8 kg of product were collected.
  • the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
  • the silicon-based negative electrode material in this comparative example includes an inner core and a carbon film covering the surface of the inner core.
  • the inner core contains silicon, silicon oxide and magnesium silicate, and the thickness of the carbon film is 100 nm.
  • the mass fraction of Mg element is 35%.
  • a collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite, and the reaction is completed. The equipment was then cooled and 15 kg of product was collected.
  • the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
  • the prepared silicon composite anode material particles were cut with a Hitachi E-3500 ion mill, and the morphology and structure of the cross-section were observed on a Hitachi S-4800 cold field emission scanning electron microscope. The results are shown in Figures 1 to 6.
  • FIG. 1 is an electron microscope photograph of the cross section of the silicon composite negative electrode material particle in Example 1.
  • FIG. 1 It can be seen from FIG. 1 that the inner core 120 of the material forms a uniform homogeneous structure with a uniform texture, which can illustrate the silicon, silicon oxide and M silicate three in Example 1 of the embodiment. The former is a homogeneous state, and the three are mixed and uniformly distributed. At the same time, it can be seen that the outer dark part is a carbon coating.
  • FIG. 2 is an electron microscope photograph of the cross section of the silicon composite negative electrode material particle in Example 2.
  • FIG. 2 It can be seen from FIG. 2 that the core 120 of the material is also uniform in texture, so that the silicon, silicon oxide and silicate of M in Example 2 also show a state of uniform mixing.
  • the outer dark part is a carbon coating.
  • FIG. 3 is an electron microscope photograph of the cross section of the silicon composite negative electrode material particle in Comparative Example 1.
  • FIG. 3 It can be seen from FIG. 3 that the thickness of the carbon cladding layer is thinner than that of Examples 1 and 2.
  • FIG. 4 is an electron microscope photograph of the cross section of the silicon composite negative electrode material particle in Comparative Example 2.
  • FIG. 4 It can be seen from FIG. 4 that the thickness of the carbon cladding layer is thicker than that of Examples 1 and 2.
  • FIG. 5 is an electron microscope photograph of the cross section of the silicon composite negative electrode material particle in Comparative Example 3.
  • FIG. 5 It can be seen from FIG. 5 that the thickness of the carbon cladding layer is thinner than that of Examples 1 and 2.
  • FIG. 6 is an electron microscope photograph of the cross section of the silicon composite negative electrode material particle in Comparative Example 4.
  • FIG. 6 It can be seen from FIG. 6 that the thickness of the carbon cladding layer is thicker than that of Examples 1 and 2.
  • the inner core presents a number of small particle-like forms. It can be seen that when the M content in the distributed composite is higher than 30%, the excess M will rapidly react with SiO and release a large amount of heat, resulting in the generation of Si The crystal grains are very large, so it shows the appearance of uneven distribution of the inner
  • Q 1(dis) first discharge specific capacity when charging and discharging at 0.1C rate current, (mAh/g);
  • C 1(dis) the first discharge capacity when charging and discharging at 0.1C rate current, (mAh);
  • the first lithium insertion specific capacity test (mAh/g) (ie Q l(cha) ):
  • Q 1(cha) first charge specific capacity when charging and discharging at 0.1C rate current, (mAh/g);
  • the above electrochemical performance is based on the LAND battery test system of Wuhan Jinnuo Electronics Co., Ltd., under normal temperature conditions, 0.1C constant current charge and discharge, and the charge and discharge voltage is limited to 0.005 ⁇ 1.5V.
  • the first coulombic efficiencies of the experimental button cells made from the materials of Examples 1-6 and Comparative Examples 1-6 were tested at room temperature. The test results are shown in Table 1.
  • the silicon composite negative electrode material prepared by each example and the comparative example is mixed with graphite in a ratio of 10:90, and then mixed with sodium carboxymethyl cellulose CMC (as a binder) and a binder styrene-butadiene rubber SBR (as a binder).
  • Binder), conductive agent Super-P, and conductive agent KS-6 are mixed in a mass ratio of 92:2:2:2 to form a slurry, which is coated on the copper foil negative current collector 242 to control the total amount of the slurry.
  • the solid content is 50%, and through vacuum drying and rolling, the negative electrode active material layer 244 is formed, and the negative electrode 240 pole piece is prepared; the positive electrode 220 adopts a lithium piece, and uses 1mol/L LiPF
  • the three-component mixed solvent EC:DMC: EMC 1:1:1 (volume ratio)
  • the v/v solution is the electrolyte 260
  • the polypropylene microporous membrane is the separator 280 and the shell 290
  • the shell 290 is used to assemble a CR2016 simulated battery.
  • the first week discharge specific capacity (mAh/g) the first week discharge capacity/m
  • the 50th cycle discharge specific capacity (mAh/g) the 50th cycle discharge capacity/m (formula 4);
  • 50-cycle cycle retention rate (%) discharge specific capacity in the 50th cycle / discharge specific capacity in the first cycle ⁇ 100% (Formula 5);
  • the cycle performance test uses a current of 30mA for constant current charge-discharge experiments, and the charge-discharge voltage is limited to 0-1.5V.
  • the 50-cycle cycle retention rate of the experimental button battery made of the material of Example 1 was tested by using the LAND battery test system of Wuhan Jinnuo Electronics Co., Ltd.
  • the embodiment of the present disclosure limits the carbon layer thickness of the composite negative electrode material to 50nm-200nm In between, the composite negative electrode material with carbon layer thickness within this range, the surface of the composite particles can be completely covered, and the thickness is also controlled within the most suitable range, which can effectively buffer the composite during the charging and discharging process. volume expansion.
  • the thickness of the carbon layer also has a positive effect on the volume control of the material, so the capacity efficiency and cycle performance of the composite can be significantly improved.
  • Example 1 Comparative Examples 1 and 3 that when the coating thickness of the silicon composite surface is less than 50 nm, because the surface of the silicon composite particles prepared in the comparative example cannot be completely covered by the carbon layer, there are still many exposed If such a material is used in a battery, on the one hand, the exposed part will be in direct contact with the electrolyte 260, and an unstable SEI film will be formed repeatedly, resulting in excessive consumption of the electrolyte 260, resulting in decreased cycle performance.
  • Example 1 By comparing Example 1 with Comparative Examples 2 and 4, it can be seen that when the coating thickness on the surface of the silicon composite is greater than 200 nm, the carbon layer on the surface of the silicon composite particle is too thick. During the process, the thick carbon layer is easily cracked by the internal stress of the particles, resulting in the direct contact between the silicon composite and the electrolyte 260 and the deactivation of the exposed position due to loss of electrical contact, resulting in a decrease in material performance.
  • Example 1 Comparative Examples 5-6 that when the content of M in the composite is less than 1%, the amount of M that can react with SiO is very small, and Si is generated which is beneficial to improve the Coulombic efficiency of the material in the first week.
  • the amount of silicon-based anode material 100 and the silicate of M as a buffer substance in the charging and discharging process are also correspondingly small, so the first week Coulombic efficiency and cycle performance of the silicon-based negative electrode material 100 prepared with it are not significantly improved;
  • the M content is higher than 30%, the excess M will rapidly react with SiO and release a large amount of heat, resulting in extremely large Si grains, so as to prepare the silicon-based anode material 100.
  • the present disclosure illustrates the detailed process equipment and process flow of the present disclosure through the above-mentioned embodiments, but the present disclosure is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present disclosure must rely on the above-mentioned detailed process equipment and process flow. Process flow can be implemented. Those skilled in the art should understand that any improvement to the present disclosure, the equivalent replacement of each raw material of the disclosed product, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present disclosure.
  • the present disclosure illustrates the detailed method of the present disclosure through the above-mentioned embodiments, but the present disclosure is not limited to the above-mentioned detailed method, that is, it does not mean that the present disclosure must rely on the above-mentioned detailed method to be implemented.
  • Those skilled in the art should understand that any improvement to the present disclosure, the equivalent replacement of each raw material of the disclosed product, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present disclosure.
  • the present disclosure provides a silicon-based negative electrode material, a negative electrode, a lithium ion battery, and a preparation method thereof.
  • the silicon-based negative electrode material can improve the conductivity of the silicon composite, and can significantly improve the capacity efficiency and cycle performance of the silicon composite, and the prepared negative electrode and lithium ion battery have the characteristics of high capacity efficiency and cycle performance.

Abstract

A silicon-based negative electrode material (100), a negative electrode (240), and a lithium-Ion secondary battery (200) and a preparation method therefor. The silicon-based negative electrode material (100) comprises: an internal core (120), wherein the internal core (120) comprises silicon, a silicon oxide and a silicate of M, the chemical formula of the silicon oxide is SiOx, 0 < x < 2, and M is a metal; and a carbon coating (140) formed on a surface of the internal core (120), wherein the thickness of the carbon coating (140) is 50 nm-200 nm. The method comprises: performing carbon coating processing on a silicon composite to form a carbon coating (140) having a thickness of 50 nm-200 nm on a surface of the silicon composite, thereby obtaining a silicon-based negative electrode material (100). Covering a silicon composite with a carbon coating (140) having an appropriate thickness can significantly improve the coulombic efficiency and cycling performance of the silicon composite, and thus a negative electrode (240) and a lithium-ion secondary battery (200) prepared using same have the advantages of high coulombic efficiency and cycling performance.

Description

硅基负极材料、负极和锂离子电池及其制备方法Silicon-based negative electrode material, negative electrode and lithium ion battery and preparation method thereof
相关申请的交叉引用CROSS-REFERENCE TO RELATED APPLICATIONS
本申请要求于2020年07月22日提交中国专利局的申请号为2020107126754、名称为“硅基负极材料、其制备方法及锂离子二次电池”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。This application claims the priority of the Chinese Patent Application No. 2020107126754 and entitled "Silicon-Based Anode Material, Its Preparation Method and Lithium Ion Secondary Battery" filed with the China Patent Office on July 22, 2020, the entire contents of which are approved by Reference is incorporated in this application.
技术领域technical field
本公开属于储能材料及电化学领域，特别是涉及一种硅基负极材料、负极和锂离子电池及其制备方法。The present disclosure belongs to the field of energy storage materials and electrochemistry, and in particular relates to a silicon-based negative electrode material, a negative electrode, a lithium ion battery and a preparation method thereof.
背景技术Background technique
随着锂离子电池应用领域的扩展，使得锂离子电池成为研究工作的热点。负极材料作为锂离子电池的重要组成部分，影响着锂离子电池的比能量及循环寿命，一直是锂离子电池研究的重点。With the expansion of the application field of lithium-ion batteries, lithium-ion batteries have become a hot spot of research work. As an important part of lithium-ion batteries, anode materials affect the specific energy and cycle life of lithium-ion batteries, and have always been the focus of lithium-ion battery research.
传统的石墨类负极材料储存锂离子的容量较低(理论上为372mAh/g)，这导致以之制作的电池的整体容量不高的问题。目前全球的汽车工业都在由内燃机向电动汽车转变，因而对电池能量密度的要求也越来越高，所以传统的石墨类负极材料制作的锂离子电池已不能满足电动汽车的需要。开发能量密度高、功率密度高的新能锂离子电池负极材料迫在眉睫。The traditional graphite-based negative electrode material has a low capacity for storing lithium ions (theoretically 372mAh/g), which leads to the problem that the overall capacity of the battery made with it is not high. At present, the global automobile industry is transforming from internal combustion engines to electric vehicles, so the requirements for battery energy density are getting higher and higher, so lithium-ion batteries made of traditional graphite anode materials can no longer meet the needs of electric vehicles. The development of new energy lithium-ion battery anode materials with high energy density and high power density is imminent.
硅具有最高的理论比容量(4200mAh/g)且较低的放电电位，是最有希望成为下一代锂离子电池的负极材料的。但因硅在充电和放电循环中会出现巨大的体积膨胀(高达300％)从而导致负极破裂和粉化，限制了其商业化应用。在硅的化合物中，氧化亚硅是一种具有较高比容量的负极材料，相较于硅，其在充放电过程中体积变化较小。此外，还具有工作电压低，原料来源广泛等优点。Silicon has the highest theoretical specific capacity (4200mAh/g) and lower discharge potential, and is the most promising anode material for next-generation lithium-ion batteries. However, the large volume expansion (up to 300%) of silicon during charge and discharge cycles can lead to anode cracking and pulverization, which limits its commercial application. Among silicon compounds, silicon oxide is a negative electrode material with higher specific capacity, and its volume change is smaller during charge and discharge than silicon. In addition, it also has the advantages of low working voltage and wide source of raw materials.
虽然氧化亚硅能缓解自身体积膨胀，但是首次循环过程中，由于不可逆的Li 2O的生成，增加了对正极材料中Li的消耗，增加了不可逆容量，导致其首次库伦效率低。这些因素极大地限制了氧化亚硅电化学性能的发挥及其实际应用。为解决上述问题，常用的方法为氧化亚硅中引入锂源但是，由于使用的金属锂具有极强的活性(易燃易爆)，在材料及电极的制备过程具有较大的危险性，导致其实际应用困难。另一方面，由于工艺复杂、成本高昂，并且要使用强腐蚀性及强毒性的原料，阻碍了其产业化应用。 Although silicon oxide can alleviate its own volume expansion, due to the generation of irreversible Li 2 O during the first cycle, the consumption of Li in the cathode material is increased, and the irreversible capacity is increased, resulting in a low first Coulomb efficiency. These factors greatly limit the development of the electrochemical performance of SiO and its practical application. In order to solve the above problems, the commonly used method is to introduce a lithium source into the silicon oxide. However, due to the extremely strong activity (flammable and explosive) of the metal lithium used, the preparation process of the material and the electrode has a greater risk, resulting in Its practical application is difficult. On the other hand, due to the complex process, high cost, and the use of highly corrosive and highly toxic raw materials, its industrial application is hindered.
因此，需要一种成本低廉并且易于工业化实施的技术，以解决上面的问题。Therefore, a low-cost and easy-to-industrial technology is needed to solve the above problems.
发明内容SUMMARY OF THE INVENTION
本公开提供一种硅基负极材料，所述硅基负极材料包括：The present disclosure provides a silicon-based negative electrode material, and the silicon-based negative electrode material includes:
内核，所述内核包括硅、硅氧化物及M的硅酸盐；所述硅氧化物的化学式为SiO x，0＜x＜2，所述M为金属；及 Core, said core comprising a silicate of silicon, silicon oxide and M; and the formula of the silicon oxide is SiO x, 0 <x <2 , M is a metal; and
碳被膜，所述碳被膜形成于所述内核的表面，所述碳被膜的厚度为50nm-200nm。A carbon coating, the carbon coating is formed on the surface of the inner core, and the thickness of the carbon coating is 50 nm-200 nm.
在一些实施方式中，所述碳被膜的厚度为100nm-200nm。In some embodiments, the thickness of the carbon coating is 100 nm-200 nm.
在一些实施方式中，所述M包括但不限于Li、Mg、Al、Zn、Ca、Na和Ti中的任意一种或至少两种的组合。In some embodiments, the M includes, but is not limited to, any one or a combination of at least two of Li, Mg, Al, Zn, Ca, Na, and Ti.
在一些实施方式中，所述M还包括Fe或者Fe与Li、Mg、Al、Zn、Ca、Na和Ti中的任意一种或至少两种的组合。In some embodiments, the M further includes Fe or a combination of Fe and any one or at least two of Li, Mg, Al, Zn, Ca, Na, and Ti.
在一些实施方式中，以所述硅基负极材料的总质量为100％计，所述M元素的质量分数介于1-30％之间。In some embodiments, based on the total mass of the silicon-based negative electrode material as 100%, the mass fraction of the M element is between 1-30%.
在一些实施方式中，所述硅基负极材料的平均粒径D50为0.5μm-40μm。In some embodiments, the average particle size D50 of the silicon-based negative electrode material is 0.5 μm-40 μm.
在一些实施方式中，所述硅基负极材料的比表面积为0.5m 2/g-40m 2/g。 In some embodiments, the silicon-based negative electrode material has a specific surface area of 0.5 m 2 /g to 40 m 2 /g.
本公开提供一种所述硅基负极材料的制备方法，所述方法包括以下步骤：The present disclosure provides a preparation method of the silicon-based negative electrode material, and the method includes the following steps:
将SiO y蒸汽和M单质蒸汽混合，进行冷却凝结处理，得到硅复合物，其中，0＜y＜2； Mixing SiO y steam and M elemental steam, and performing cooling and condensation treatment to obtain a silicon composite, wherein 0<y<2;
对所述硅复合物进行碳包覆处理，以在所述硅复合物表面形成厚度为50nm-200nm的碳被膜，得到硅基负极材料。Carbon coating treatment is performed on the silicon composite to form a carbon film with a thickness of 50 nm to 200 nm on the surface of the silicon composite to obtain a silicon-based negative electrode material.
本公开提供一种所述的硅基负极材料的制备方法，所述方法包括以下步骤：The present disclosure provides a method for preparing the silicon-based negative electrode material, and the method includes the following steps:
将SiO蒸汽和M单质蒸汽混合，进行冷却凝结处理，得到硅复合物；Mixing SiO vapor and M elemental vapor, and cooling and condensing to obtain silicon composite;
对所述硅复合物进行碳包覆处理，以在所述硅复合物表面形成厚度为50nm-200nm的碳被膜，得到硅基负极材料。Carbon coating treatment is performed on the silicon composite to form a carbon film with a thickness of 50 nm to 200 nm on the surface of the silicon composite to obtain a silicon-based negative electrode material.
作为本公开所述方法的可选的技术方案，所述SiO蒸汽和M单质蒸汽的制备方法包括以下步骤：调控含有SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料的反应环境的温度和压力，得到所述SiO蒸汽和所述M单质蒸汽。As an optional technical solution of the method of the present disclosure, the preparation method of the SiO steam and the M elemental steam includes the following steps: regulating and controlling the raw materials containing SiO and/or preparing the SiO and the M element and/or the raw material for preparing the M element. The temperature and pressure of the reaction environment are used to obtain the SiO vapor and the M elemental vapor.
在一些实施方式中，所述制备SiO的原料包括将Si与SiO 2以质量比为1:1.5-1:2.5混合后的混合物。 In some embodiments, the raw materials for preparing SiO include a mixture of Si and SiO 2 in a mass ratio of 1:1.5-1:2.5.
在一些实施方式中，所述制备M单质的原料包括用于制备M单质的物质混合后的混合物。In some embodiments, the raw materials for preparing the elemental M include a mixture of the materials used for preparing the elemental M.
在一些实施方式中，所述反应环境为真空环境。In some embodiments, the reaction environment is a vacuum environment.
在一些实施方式中，形成所述含有SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料的反应环境具体操作为：将所述SiO和/或制备SiO的原料置于真空炉中。In some embodiments, the specific operation of the reaction environment for forming the SiO-containing and/or SiO-preparing raw materials and the M elemental substance and/or the M elemental-preparing raw materials is: placing the SiO and/or the SiO-preparing raw materials in a vacuum in the furnace.
在一些实施方式中，将SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料置于反应器中的步骤包括：将所述SiO和/或制备SiO的原料置于真空炉靠近炉尾的一端，将所述M单质和/或制备M单质的原料置于真空炉靠近炉口的一端。In some embodiments, the step of placing the SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO in a vacuum furnace Close to one end of the furnace tail, place the M element and/or the raw material for preparing M element in the end of the vacuum furnace close to the furnace mouth.
或者，将SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料置于反应器中的步骤包括：将所述SiO和/或制备SiO的原料置于真空炉靠近炉口的一端，将所述M单质和/或制备M单质的原料置于真空炉靠近炉尾的一端。Alternatively, the step of placing the SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO in a vacuum furnace close to the furnace mouth At one end, the M element and/or the raw material for preparing M element is placed at the end of the vacuum furnace close to the furnace tail.
或者，将SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料置于反应器中的步骤包括：将所述SiO和/或制备SiO的原料与所述M单质和/或制备M单质的原料混合后置于真空炉内。Alternatively, the step of placing SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO with the M element and/or The raw materials for preparing M elemental substance are mixed and placed in a vacuum furnace.
在一些实施方式中，调控含有SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料的反应环境的温度和压力步骤中的所述温度为1200℃-1600℃，所述压力为0.1Pa-500Pa。In some embodiments, the temperature in the step of regulating the temperature and pressure of the reaction environment containing SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M is 1200°C-1600°C, and the pressure It is 0.1Pa-500Pa.
作为本公开实施方式所述方法的可选的技术方案，所述方法还包括在得到硅复合物步骤之后，对所述硅复合物进行碳包覆处理步骤之前进行下述步骤：对所述硅复合物粉碎、分级和烧成中的至少一种。As an optional technical solution of the method described in the embodiment of the present disclosure, the method further includes performing the following step after the step of obtaining the silicon composite and before the carbon coating treatment step on the silicon composite: At least one of crushing, classifying and firing the composite.
在一些实施方式中，所述方法还包括在得到硅复合物凝结成固相材料步骤之后，对所述硅复合物固相材料进行碳包覆处理步骤之前进行下述步骤：所述步骤按方案Ⅰ、方案Ⅱ或方案Ⅲ中的任意一种进行。In some embodiments, the method further includes performing the following steps after the step of obtaining the silicon composite to condense into a solid phase material, and before the carbon coating treatment step on the silicon composite solid phase material: the step is according to the scheme Any one of I, Scheme II or Scheme III is carried out.
其中，所述方案Ⅰ为：对所述硅复合物依次进行粉碎、分级、烧成处理；Wherein, the scheme I is: pulverizing, classifying and firing the silicon composite in sequence;
所述方案Ⅱ为：对所述硅复合物依次进行粉碎、烧成、分级处理；The scheme II is: pulverizing, sintering and classifying the silicon composite in sequence;
所述方案Ⅲ为：对所述硅复合物依次进行烧成、粉碎、分级处理。The scheme III is: firing, pulverizing and classifying the silicon composite in sequence.
在一些实施方式中，对所述硅复合物进行碳包覆处理的步骤中的所述碳包覆的方式包 括：气相包覆、液相包覆和固相包覆中的任意一种或至少两种的组合。In some embodiments, the carbon coating method in the step of carbon coating treatment on the silicon composite includes: any one of gas phase coating, liquid phase coating and solid phase coating or at least combination of the two.
在一些实施方式中，对所述硅复合物进行碳包覆处理的步骤中的碳包覆采用气相包覆的方式进行，通过控制含碳气体的流量及通入时间控制碳被膜的厚度，获得复合物负极材料。In some embodiments, the carbon coating in the step of carbon coating treatment on the silicon composite is performed by gas-phase coating. composite anode material.
在一些实施方式中，对所述硅复合物进行碳包覆处理的步骤中的碳包覆采用固相包覆或液相包覆的方式进行，通过控制混入含碳物质的质量及烧成温度控制碳被膜的厚度，获得复合物负极材料。In some embodiments, the carbon coating in the step of carbon coating treatment on the silicon composite is performed by means of solid phase coating or liquid phase coating, by controlling the mass and firing temperature of the carbon-containing material mixed in The thickness of the carbon coating is controlled to obtain a composite negative electrode material.
作为本公开实施方式所述方法的可选技术方案，所述方法包括以下步骤：As an optional technical solution of the method described in the embodiment of the present disclosure, the method includes the following steps:
将SiO或制备SiO的原料及M单质或制备M单质的原料放入真空炉中；Put SiO or the raw material for preparing SiO and M elemental substance or the raw material for preparing M elemental substance into the vacuum furnace;
在1200-1600℃、0.5-500Pa的环境下生成M蒸汽与SiO蒸汽；Generate M steam and SiO steam under the environment of 1200-1600℃ and 0.5-500Pa;
将所述M蒸汽与SiO蒸汽在置于真空炉内的混合装置中混合均匀，然后进行冷却凝结，得到固相的M与SiO混合的硅复合物；The M steam and the SiO steam are uniformly mixed in a mixing device placed in a vacuum furnace, and then cooled and condensed to obtain a solid-phase M and SiO mixed silicon composite;
对所述硅复合物进行粉碎和分级，制备成粉体材料；pulverizing and classifying the silicon composite to prepare a powder material;
将所述粉体材料进行碳包覆，使硅复合物表面的碳被膜厚度为50nm-200nm之间，得到硅基负极材料。The powder material is coated with carbon, so that the thickness of the carbon film on the surface of the silicon composite is between 50 nm and 200 nm to obtain a silicon-based negative electrode material.
本公开提供一种负极，所述负极包括所述硅基负极材料。The present disclosure provides a negative electrode comprising the silicon-based negative electrode material.
本公开提供一种锂离子二次电池，所述锂离子二次电池包含所述硅基负极材料。The present disclosure provides a lithium ion secondary battery including the silicon-based negative electrode material.
附图说明Description of drawings
为了更清楚地说明本公开实施方式的技术方案，下面将对实施方式中所需要使用的附图作简单地介绍，应当理解，以下附图仅示例地表示本公开的实施方式，图中尺寸比例与实施方式的真实比例并不能直接对应，同时以下附图仅示出了本公开的某些实施方式，因此不应被看作是对范围的限定。In order to illustrate the technical solutions of the embodiments of the present disclosure more clearly, the accompanying drawings required in the embodiments will be briefly introduced below. It should be understood that the following drawings only represent the embodiments of the present disclosure by way of example, and the size ratios in the drawings are It does not directly correspond to the true scale of the embodiments, and the following drawings illustrate only certain embodiments of the present disclosure and should not be considered as limiting the scope.
图1为实施例1中硅复合物负极材料颗粒截面的电镜照片；Fig. 1 is the electron microscope photograph of the particle cross section of silicon composite negative electrode material in embodiment 1;
图2为实施例2中硅复合物负极材料颗粒截面的电镜照片；Fig. 2 is the electron microscope photograph of the particle cross section of silicon composite negative electrode material among the embodiment 2;
图3为对比例1中硅复合物负极材料颗粒截面的电镜照片；Fig. 3 is the electron microscope photograph of the particle cross section of silicon composite negative electrode material in Comparative Example 1;
图4为对比例2中硅复合物负极材料颗粒截面的电镜照片；Fig. 4 is the electron microscope photograph of the particle cross section of silicon composite negative electrode material in Comparative Example 2;
图5为对比例3中硅复合物负极材料颗粒截面的电镜照片；Fig. 5 is the electron microscope photograph of the particle cross section of silicon composite negative electrode material in Comparative Example 3;
图6为对比例4中硅复合物负极材料颗粒截面的电镜照片；Fig. 6 is the electron microscope photograph of the particle cross section of silicon composite negative electrode material in Comparative Example 4;
图7为本公开一些实施方式提供的硅基负极材料的结构示意图；7 is a schematic structural diagram of a silicon-based negative electrode material provided by some embodiments of the present disclosure;
图8是本公开一些实施方式提供的阴极结构示意图；8 is a schematic diagram of a cathode structure provided by some embodiments of the present disclosure;
图9是本公开一些实施方式提供的电池示意图；9 is a schematic diagram of a battery provided by some embodiments of the present disclosure;
附图标记，100-硅基负极材料；120-内核；140-碳被膜；200-锂离子二次电池；220-正极；240-负极；242-负极集流体；244-负极活性材料层；260-电解液；280-隔膜；290-外壳。Reference numerals, 100-silicon-based negative electrode material; 120-core; 140-carbon coating; 200-lithium ion secondary battery; 220-positive electrode; 240-negative electrode; 242-negative electrode current collector; 244-negative electrode active material layer; 260 - Electrolyte; 280 - Diaphragm; 290 - Shell.
实施方式Implementation
为了便于理解本发明，下面结合实施例的方式对本发明的技术方案做详细说明，在下面的描述中阐述了很多具体细节以便于充分理解本发明。In order to facilitate the understanding of the present invention, the technical solutions of the present invention are described in detail below with reference to the embodiments, and many specific details are set forth in the following description to facilitate a full understanding of the present invention.
但是本发明能够以很多不同于在此描述的其它方式来实施，本领域技术人员可以在不违背本发明内涵的情况下做类似改进，因此本发明不受下面公开的具体实施的限制。除非另有限定，本文使用的所有技术以及科学术语具有与本发明所属领域普通技术人员通常理解的相同的含义。当存在矛盾时，以本说明书中的定义为准。However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific implementation disclosed below. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the definitions in this specification will control.
一实施方式提供一种硅基负极材料、其制备方法及锂离子二次电池。一些实施方式中的制备工艺简单、成本低廉，得到的硅基负极材料应用于锂离子二次电池具有首次充放电 效率高、循环性能好的优点。An embodiment provides a silicon-based negative electrode material, a preparation method thereof, and a lithium ion secondary battery. In some embodiments, the preparation process is simple and the cost is low, and the obtained silicon-based negative electrode material has the advantages of high initial charge-discharge efficiency and good cycle performance when applied to a lithium ion secondary battery.
I.硅基负极材料I. Silicon-based anode material
如图7所示，一些实施方式提供一种硅基负极材料100，所述硅基负极材料100包括：As shown in FIG. 7 , some embodiments provide a silicon-based negative electrode material 100 , and the silicon-based negative electrode material 100 includes:
内核120，所述内核120包括硅、硅氧化物及M的硅酸盐；所述硅氧化物的化学式为SiO x，0＜x＜2，所述M为金属；及碳被膜140，所述碳被膜140形成于所述内核120的表面，所述碳被膜140的厚度为50nm-200nm。 Core 120, the core 120 silicates include silicon, silicon oxide and M; and the chemical formula of the silicon oxide is SiO x, 0 <x <2 , M is a metal; and a carbon film 140, the The carbon coating 140 is formed on the surface of the inner core 120, and the thickness of the carbon coating 140 is 50 nm-200 nm.
不受理论的约束，据信硅、硅氧化物及M的硅酸盐三者为均相混合均匀的状态，三者为原子级别的混合均匀分布。Without being bound by theory, it is believed that all three of silicon, silicon oxide, and silicate of M are in a state of homogeneous mixing and uniform distribution at the atomic level.
在实施方式中，所述硅氧化物的化学式SiO x中，x等于2，即为二氧化硅时，其电极活性较低；x大于2，则为二氧化硅和其他化合物的混合物，电极活性同样较低。 In an embodiment, the chemical formula of the silicon oxide SiO x, x is equal to 2, that is, when silica, which is a lower electrode active; X is greater than 2, and the other was a mixture of silica compound, an electrode active Also lower.
(A)碳被膜(A) Carbon coating
一些实施方式中，硅基负极材料100中，碳被膜140的厚度例如50nm、60nm、80nm、90nm、100nm、110nm、125nm、135nm、150nm、170nm、180nm或200nm等，x例如0.3、0.5、1、1.2、1.5、1.7、1.9等。In some embodiments, in the silicon-based negative electrode material 100, the thickness of the carbon coating 140 is, for example, 50 nm, 60 nm, 80 nm, 90 nm, 100 nm, 110 nm, 125 nm, 135 nm, 150 nm, 170 nm, 180 nm, or 200 nm, etc., and x is, for example, 0.3, 0.5, 1 , 1.2, 1.5, 1.7, 1.9, etc.
在一些实施方式中，所述碳被膜140的厚度为50nm-100nm、100nm-130nm、130nm-160nm或100nm-200nm。In some embodiments, the thickness of the carbon coating 140 is 50 nm-100 nm, 100 nm-130 nm, 130 nm-160 nm, or 100 nm-200 nm.
一些实施方式中，硅基负极材料100，内核120中均匀的分布着硅、硅氧化物及硅酸盐，内核120的表面均匀的覆盖着一层厚度在50nm-200nm之间的碳被膜140，至少在一些实施方式中，碳被膜140的厚度在100nm-200nm之间，以获得更佳的电化学性能。In some embodiments, in the silicon-based negative electrode material 100, silicon, silicon oxide and silicate are uniformly distributed in the inner core 120, and the surface of the inner core 120 is uniformly covered with a carbon film 140 with a thickness between 50 nm and 200 nm, In at least some embodiments, the thickness of the carbon coating 140 is between 100 nm-200 nm for better electrochemical performance.
本公开实施方式的方法中，通过控制碳包覆过程中的包覆工艺，获得了碳被膜厚度在50nm-200nm之间的硅基负极材料。In the method of the embodiment of the present disclosure, by controlling the coating process in the carbon coating process, a silicon-based negative electrode material with a carbon coating thickness between 50 nm and 200 nm is obtained.
在一些实施方式中，在真空环境下通过混合SiO蒸汽和M蒸汽并使之冷却形成的沉积体，可以制备M元素掺杂的硅复合物。通过蒸汽混合，可以实现SiO和M元素的原子级别的均匀混合。但该复合物的导电性极差，直接用作负极材料时其容量不能有效发挥。公开人采取的解决办法是在该材料的表面覆盖一层碳被膜140，提高该硅复合物的导电性以确保容量的发挥并通过大量实验发现碳层的厚度介于50nm-200nm的硅基负极材料100时，可以有效的实现复合物表面无缺陷包覆，电极材料的容量效率及循环性能最优。In some embodiments, M element doped silicon composites can be prepared by mixing SiO vapor and M vapor and cooling the resulting deposit in a vacuum environment. Through steam mixing, atomic-level homogeneous mixing of SiO and M elements can be achieved. However, the conductivity of the composite is extremely poor, and its capacity cannot be effectively exerted when it is directly used as a negative electrode material. The solution adopted by the public is to cover a layer of carbon film 140 on the surface of the material, to improve the conductivity of the silicon composite to ensure the performance of the capacity, and through a large number of experiments, it is found that the thickness of the carbon layer is between 50nm-200nm silicon-based negative electrode When the material is 100, defect-free coating on the surface of the composite can be effectively achieved, and the capacity efficiency and cycle performance of the electrode material are optimal.
在一些实施方式中，当碳层的厚度小于50nm时，硅复合物颗粒的表面不能被完全被碳层覆盖，仍存在较多的裸露部位，这样的材料应用在电池中，一方面裸露部位会与电解液260直接接触，反复生成不稳定的SEI膜，导致电解液260被过度消耗，造成循环性能下降；另一方面，裸露的部位导电性极差，该部位的活性材料不能有效地进行嵌脱锂反应，会造成容量的减少。In some embodiments, when the thickness of the carbon layer is less than 50 nm, the surface of the silicon composite particles cannot be completely covered by the carbon layer, and there are still many exposed parts. When such a material is used in batteries, the exposed parts will In direct contact with the electrolyte 260, an unstable SEI film is repeatedly generated, resulting in excessive consumption of the electrolyte 260, resulting in decreased cycle performance; on the other hand, the exposed part has extremely poor conductivity, and the active material in this part cannot be effectively embedded. The delithiation reaction will cause a decrease in capacity.
当碳层的厚度大于200nm时，硅复合物颗粒表面的碳层过厚，这样的材料应用在电池中时，在反复的充放电过程中偏厚的碳层易受到颗粒内部应力的作用而开裂，造成硅复合物与电解液260直接接触以及裸露位置因失去电接触而失活，从而导致材料性能的降低。When the thickness of the carbon layer is greater than 200 nm, the carbon layer on the surface of the silicon composite particle is too thick. When such a material is used in a battery, the thick carbon layer is easily cracked by the internal stress of the particle during repeated charge and discharge processes. , resulting in the direct contact of the silicon composite with the electrolyte 260 and the deactivation of the exposed site due to loss of electrical contact, resulting in a reduction in material performance.
在一些实施方式中，硅复合物负极材料的碳层厚度限定在50nm-200nm之间，碳层厚度在此范围内的硅基负极材料100，其中硅复合物颗粒的表面能够被完全覆盖，且厚度控制在最适宜的范围内，能够有效的缓冲充放电过程中复合物的体积膨胀。应用在电池中时既不会出现前述因部分位置裸露而出现的电解液260过度消耗及容量减少的问题，也不会出现因碳层过厚而出现的循环过程中碳层开裂的问题，且适宜厚度的碳层对材料的体积控制也产生了积极作用。所以能够显著的提升硅复合物的容量效率及循环性能。例如，碳层厚度为100nm的硅基负极材料100，具有接近1400mAh/g的可逆容量以及90％的首周库伦效率，其50周循环保持率也达到了90％以上。In some embodiments, the carbon layer thickness of the silicon composite negative electrode material is limited to between 50 nm and 200 nm, and the silicon-based negative electrode material 100 with the carbon layer thickness within this range, wherein the surface of the silicon composite particles can be completely covered, and The thickness is controlled within the optimum range, which can effectively buffer the volume expansion of the composite during charging and discharging. When applied in batteries, the aforementioned problems of excessive consumption of electrolyte 260 and capacity reduction due to exposed partial positions, and the problem of cracking of the carbon layer during cycling due to excessively thick carbon layer, will not occur, and A carbon layer of suitable thickness also has a positive effect on the volume control of the material. Therefore, the capacity efficiency and cycle performance of the silicon composite can be significantly improved. For example, the silicon-based anode material 100 with a carbon layer thickness of 100 nm has a reversible capacity close to 1400 mAh/g, a first-week Coulombic efficiency of 90%, and a 50-cycle cycle retention rate of more than 90%.
(B)掺杂元素与复合材料(B) Doping elements and composite materials
以下作为一些实施方式中可选的技术方案，但不作为对本公开实施方式提供的技术方案的限制，通过以下可选的技术方案，可以更好的达到和实现本公开的技术效果。在一些实施方式中，所述M包括但不限于Li、Mg、Al、Zn、Ca、Na和Ti中的任意一种或至少两种的组合。The following are optional technical solutions in some embodiments, but are not intended to limit the technical solutions provided by the embodiments of the present disclosure. Through the following optional technical solutions, the technical effects of the present disclosure can be better achieved and realized. In some embodiments, the M includes, but is not limited to, any one or a combination of at least two of Li, Mg, Al, Zn, Ca, Na, and Ti.
在一些实施方式中，所述M还包括Fe或者Fe与Li、Mg、Al、Zn、Ca、Na和Ti中的任意一种或至少两种的组合。In some embodiments, the M further includes Fe or a combination of Fe and any one or at least two of Li, Mg, Al, Zn, Ca, Na, and Ti.
在一些实施方式中，以所述硅基负极材料100的总质量为100％计，所述M元素的质量分数介于1-30％、1-7％、6％-8％、8％-12％、12％-20％或20％-30％之间，例如1％、3％、5％、6％、8％、10％、13％、16％、20％、22.5％、25％、28％或30％等。M元素的质量分数在上述范围内，可避免充放电循环过程中，出现的巨大体积膨胀，从而防止容量损失及性能劣化；同时有效地进一步提升复合材料的首周库伦效率。M元素的质量分数大于30％，M与SiO蒸汽冷却沉积后会剧烈反应，生成尺寸较大的Si颗粒，在制作成电池后的充放电循环过程中，会出现巨大的体积膨胀，从极片表面脱落，产生容量损失及性能劣化；当M元素的质量分数小于1％时，与SiO反应的M太少，生成的Si的量也相应的少，不能有效的提升复合材料的首周库伦效率，无实际意义。In some embodiments, based on the total mass of the silicon-based negative electrode material 100 as 100%, the mass fraction of the M element ranges from 1-30%, 1-7%, 6%-8%, 8%- 12%, 12%-20% or between 20%-30%, e.g. 1%, 3%, 5%, 6%, 8%, 10%, 13%, 16%, 20%, 22.5%, 25% , 28% or 30%, etc. The mass fraction of M element within the above range can avoid huge volume expansion during the charge-discharge cycle, thereby preventing capacity loss and performance degradation; at the same time, it can effectively further improve the first-week Coulomb efficiency of the composite material. The mass fraction of M element is greater than 30%, M will react violently with SiO vapor after cooling and deposition, and generate Si particles with larger size. The surface peels off, resulting in capacity loss and performance degradation; when the mass fraction of M element is less than 1%, too little M reacts with SiO, and the amount of Si generated is correspondingly small, which cannot effectively improve the first week Coulomb efficiency of the composite material , has no practical significance.
在一些实施方式中，所述硅基负极材料100的平均粒径D50为0.5μm-40μm，例如0.5μm、1μm、3μm、5μm、10μm、15μm、20μm、25μm、30μm、35μm或40μm等。平均粒径在上述范围内，可提高电池中电解液260的利用率，协同以上技术特征进一步提高电池的循环性能。硅基负极材料的平均粒径过大，则不利于电极材料工艺的制造，粒径过小，比表面积过大，在充放电的过程中，会与电解液260发生副反应，会进一步消耗电解液260，使得电极的循环性能降低，影响电池寿命。In some embodiments, the average particle size D50 of the silicon-based negative electrode material 100 is 0.5 μm-40 μm, such as 0.5 μm, 1 μm, 3 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, or 40 μm. When the average particle size is within the above range, the utilization rate of the electrolyte 260 in the battery can be improved, and the cycle performance of the battery can be further improved in conjunction with the above technical features. If the average particle size of the silicon-based negative electrode material is too large, it is not conducive to the manufacture of the electrode material process. If the particle size is too small, the specific surface area is too large. During the charging and discharging process, a side reaction will occur with the electrolyte 260, which will further consume the electrolysis. Liquid 260, which reduces the cycle performance of the electrode and affects the battery life.
在一些实施方式中，所述硅基负极材料100的比表面积为0.5m 2/g-40m 2/g，例如0.5m 2/g、2m 2/g、5m 2/g、8m 2/g、12m 2/g、15m 2/g、20m 2/g、25m 2/g、30m 2/g、35m 2/g或40m 2/g等。 In some embodiments, the specific surface area of the silicon-based negative electrode material 100 is 0.5m 2 /g-40m 2 /g, such as 0.5m 2 /g, 2m 2 /g, 5m 2 /g, 8m 2 /g, 12m 2 /g, 15m 2 /g, 20m 2 /g, 25m 2 /g, 30m 2 /g, 35m 2 /g or 40m 2 /g, etc.
II.硅基负极材料的制备II. Preparation of Si-based Anode Materials
一实施方式提供所述的硅基负极材料100的制备方法，所述方法包括以下步骤：An embodiment provides the preparation method of the silicon-based negative electrode material 100, and the method includes the following steps:
将SiO y蒸汽和M单质蒸汽混合，进行冷却凝结处理，得到硅复合物，其中，0＜y＜2； Mixing SiO y steam and M elemental steam, and performing cooling and condensation treatment to obtain a silicon composite, wherein 0<y<2;
对所述硅复合物进行碳包覆处理，以在所述硅复合物表面形成厚度为50nm-200nm的碳被膜140，得到硅基负极材料100。A carbon coating treatment is performed on the silicon composite to form a carbon coating 140 with a thickness of 50 nm-200 nm on the surface of the silicon composite to obtain a silicon-based negative electrode material 100 .
在一些实施方式中，所述SiO y中，0＜y＜1、1＜y＜2或0.3＜y＜2。 In some embodiments, in the SiO y , 0<y<1, 1<y<2, or 0.3<y<2.
在一些实施方式中，所述SiO y中，y＝1。 In some embodiments, in the SiO y , y=1.
在一些实施方式中，所述方法包括以下步骤：In some embodiments, the method includes the steps of:
将SiO蒸汽和M单质蒸汽混合，进行冷却凝结处理，得到硅复合物；Mixing SiO vapor and M elemental vapor, and cooling and condensing to obtain silicon composite;
对所述硅复合物进行碳包覆处理，以在所述硅复合物表面形成厚度为50nm-200nm的碳被膜140，得到硅基负极材料100。A carbon coating treatment is performed on the silicon composite to form a carbon coating 140 with a thickness of 50 nm-200 nm on the surface of the silicon composite to obtain a silicon-based negative electrode material 100 .
本公开实施方式的方法中，通过控制碳包覆过程中的包覆工艺，获得了碳被膜140厚度在50nm-200nm之间的硅基负极材料100。In the method of the embodiment of the present disclosure, by controlling the coating process in the carbon coating process, the silicon-based negative electrode material 100 with the thickness of the carbon coating 140 between 50 nm and 200 nm is obtained.
(A)SiO蒸汽和M单质蒸汽的制备(A) Preparation of SiO steam and M elemental steam
作为本公开所述方法的可选的技术方案，所述SiO蒸汽和M单质蒸汽的制备方法包括以下步骤：调控含有SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料的反应环境的温度和压力，得到所述SiO蒸汽和所述M单质蒸汽。As an optional technical solution of the method of the present disclosure, the preparation method of the SiO steam and the M elemental steam includes the following steps: regulating and controlling the raw materials containing SiO and/or preparing the SiO and the M element and/or the raw material for preparing the M element. The temperature and pressure of the reaction environment are used to obtain the SiO vapor and the M elemental vapor.
在一些实施方式中，所述制备SiO的原料包括将Si与SiO 2以质量比为1:1.5-1:2.5混合后的混合物，例如质量比为1:1.5、1:1.7、1:1.9、1:2.0、1:2.2、1:2.3、1:2.4、1:2.5。 In some embodiments, the raw materials for preparing SiO include a mixture of Si and SiO 2 mixed in a mass ratio of 1:1.5-1:2.5, for example, a mass ratio of 1:1.5, 1:1.7, 1:1.9, 1:2.0, 1:2.2, 1:2.3, 1:2.4, 1:2.5.
在一些实施方式中，所述制备M单质的原料包括用于制备M单质的物质混合后的混合 物。In some embodiments, the raw material for preparing M elemental substance includes a mixture after the substances used for preparing M elemental substance are mixed.
在一些实施方式中，所述反应环境为真空环境。In some embodiments, the reaction environment is a vacuum environment.
在一些实施方式中，形成所述含有SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料的反应环境具体操作为：将所述SiO和/或制备SiO的原料置于真空炉中。In some embodiments, the specific operation of the reaction environment for forming the SiO-containing and/or SiO-preparing raw materials and the M elemental substance and/or the M elemental-preparing raw materials is: placing the SiO and/or the SiO-preparing raw materials in a vacuum in the furnace.
在一些实施方式中，将所述M单质和/或制备M单质的原料置于真空炉中。In some embodiments, the elemental M and/or the raw materials for preparing the elemental M are placed in a vacuum furnace.
本公开实施方式的方法中，各原料按照化学计量比混合，以完全生成产物硅基负极材料100。In the method of the embodiment of the present disclosure, each raw material is mixed according to a stoichiometric ratio to completely generate the product silicon-based negative electrode material 100 .
本公开实施方式的方法中，所述凝结可通过下述方式实现：在反应器内的一端设置混合装置及冷凝装置，SiO蒸汽和M蒸汽在通过混合装置时被均匀混合，然后在冷凝装置内凝结成固相材料。In the method of the embodiment of the present disclosure, the condensation can be achieved by the following methods: a mixing device and a condensing device are arranged at one end of the reactor, the SiO steam and the M steam are uniformly mixed when passing through the mixing device, and then the condensing device is Condensed into a solid phase material.
在一些实施方式中，将SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料置于反应器中的步骤包括：将所述SiO和/或制备SiO的原料置于真空炉靠近炉尾的一端，将所述M单质和/或制备M单质的原料置于真空炉靠近炉口的一端。In some embodiments, the step of placing the SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO in a vacuum furnace Close to one end of the furnace tail, place the M element and/or the raw material for preparing M element in the end of the vacuum furnace close to the furnace mouth.
或者，将SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料置于反应器中的步骤包括：将所述SiO和/或制备SiO的原料置于真空炉靠近炉口的一端，将所述M单质和/或制备M单质的原料置于真空炉靠近炉尾的一端。Alternatively, the step of placing the SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO in a vacuum furnace close to the furnace mouth At one end, the M element and/or the raw material for preparing M element is placed at the end of the vacuum furnace close to the furnace tail.
或者，将SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料置于反应器中的步骤包括：将所述SiO和/或制备SiO的原料与所述M单质和/或制备M单质的原料混合后置于真空炉内。Alternatively, the step of placing the SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO with the M element and/or The raw materials for preparing M elemental substance are mixed and placed in a vacuum furnace.
在一些实施方式中，所述制备M单质的原料包括用于制备M单质的物质混合后的混合物。例如，M为Ca，M的原料可以是白云石粉末与硅铁粉的混合物。In some embodiments, the raw materials for preparing the elemental M include a mixture of the materials used for preparing the elemental M. For example, M is Ca, and the raw material of M can be a mixture of dolomite powder and ferrosilicon powder.
一些实施方式中，M为Ca，M的原料为石灰石粉末与铝粉末的混合物。In some embodiments, M is Ca, and the raw material of M is a mixture of limestone powder and aluminum powder.
一些实施方式中，M为Ca，M的原料为金属钙块体。In some embodiments, M is Ca, and the raw material of M is metallic calcium bulk.
一些实施方式中，M为Mg，M的原料为镁粉。In some embodiments, M is Mg, and the raw material of M is magnesium powder.
在一些实施方式中，调控含有SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料的反应环境的温度和压力步骤中的所述温度为1200℃-1600℃，例如1200℃、1250℃、1300℃、1400℃、1450℃、1500℃或1600℃等，所述压力为0.1Pa-500Pa，例如0.1Pa、0.5Pa、3Pa、10Pa、20Pa、35Pa、60Pa、80Pa、100Pa、150Pa、200Pa、250Pa、300Pa、350Pa、400Pa或500Pa等。在上述温度的范围内，可以使得硅氧化物和掺杂M单质以相对稳定的方式生成原子级别均匀的复合物。而温度过低，则容易出现仅蒸发单一组分的情况，温度过高，会出现蒸发不均匀、元素混合量不匹配的问题。In some embodiments, the temperature in the step of regulating the temperature and pressure of the reaction environment containing SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M is 1200°C-1600°C, such as 1200°C , 1250°C, 1300°C, 1400°C, 1450°C, 1500°C or 1600°C, etc., the pressure is 0.1Pa-500Pa, such as 0.1Pa, 0.5Pa, 3Pa, 10Pa, 20Pa, 35Pa, 60Pa, 80Pa, 100Pa, 150Pa, 200Pa, 250Pa, 300Pa, 350Pa, 400Pa or 500Pa, etc. Within the range of the above temperature, the silicon oxide and the dopant M element can be made to generate a uniform compound at the atomic level in a relatively stable manner. If the temperature is too low, it is easy to evaporate only a single component. If the temperature is too high, there will be problems of uneven evaporation and mismatch of the mixing amount of elements.
(B)硅复合物的制备(B) Preparation of silicon composites
作为本公开实施方式所述方法的可选的技术方案，所述方法还包括在得到硅复合物步骤之后，对所述硅复合物进行碳包覆处理步骤之前进行下述步骤：对所述硅复合物粉碎、分级和烧成中的至少一种。As an optional technical solution of the method described in the embodiment of the present disclosure, the method further includes performing the following step after the step of obtaining the silicon composite and before the carbon coating treatment step on the silicon composite: At least one of crushing, classifying and firing the composite.
在一些实施方式中，所述方法还包括在得到硅复合物凝结成固相材料步骤之后，对所述硅复合物固相材料进行碳包覆处理步骤之前进行下述步骤：所述步骤按方案Ⅰ、方案Ⅱ或方案Ⅲ中的任意一种进行。In some embodiments, the method further includes performing the following steps after the step of obtaining the silicon composite to condense into a solid phase material, and before the carbon coating treatment step on the silicon composite solid phase material: the step is according to the scheme Any one of I, Scheme II or Scheme III is carried out.
其中，所述方案Ⅰ为：对所述硅复合物依次进行粉碎、分级、烧成处理；Wherein, the scheme I is: pulverizing, classifying and firing the silicon composite in sequence;
所述方案Ⅱ为：对所述硅复合物依次进行粉碎、烧成、分级处理；The scheme II is: pulverizing, sintering and classifying the silicon composite in sequence;
所述方案Ⅲ为：对所述硅复合物依次进行烧成、粉碎、分级处理。The scheme III is: firing, pulverizing and classifying the silicon composite in sequence.
在一些实施方式中，对所述硅复合物进行碳包覆处理的步骤中的所述碳包覆的方式包括：气相包覆、液相包覆和固相包覆中的任意一种或至少两种的组合。In some embodiments, the carbon coating method in the step of carbon coating treatment on the silicon composite includes: any one of gas phase coating, liquid phase coating and solid phase coating or at least combination of the two.
在一些实施方式中，对所述硅复合物进行碳包覆处理的步骤中的碳包覆采用气相包覆 的方式进行，通过控制含碳气体的流量及通入时间控制碳被膜140的厚度，获得复合物负极材料。控制的具体方法为现有技术，本领域技术人员可参照现有技术进行操作，通过控制上述参数以控制碳层厚度介于50nm-200nm之间并非常规选择，其取得了预料不到的提升循环性能等电化学性能的效果。In some embodiments, the carbon coating in the step of carbon coating treatment on the silicon composite is performed by gas-phase coating, and the thickness of the carbon coating 140 is controlled by controlling the flow rate and passage time of the carbon-containing gas, A composite negative electrode material is obtained. The specific method of control is the existing technology, and those skilled in the art can operate with reference to the existing technology. It is not a conventional choice to control the thickness of the carbon layer between 50nm and 200nm by controlling the above parameters, and it has achieved an unexpected improvement cycle. performance and other electrochemical properties.
在一些实施方式中，对所述硅复合物进行碳包覆处理的步骤中的碳包覆采用固相包覆或液相包覆的方式进行，通过控制混入含碳物质的质量及烧成温度控制碳被膜140的厚度，获得复合物负极材料。控制的具体方法为现有技术，本领域技术人员可参照现有技术进行操作，通过控制上述参数以控制碳层厚度介于50nm-200nm之间并非常规选择，其取得了预料不到的提升循环性能等电化学性能的效果。In some embodiments, the carbon coating in the step of carbon coating treatment on the silicon composite is performed by means of solid phase coating or liquid phase coating, by controlling the mass and firing temperature of the carbon-containing material mixed in The thickness of the carbon coating 140 is controlled to obtain a composite negative electrode material. The specific method of control is the existing technology, and those skilled in the art can operate with reference to the existing technology. It is not a conventional choice to control the thickness of the carbon layer between 50nm and 200nm by controlling the above parameters, and it has achieved an unexpected improvement cycle. performance and other electrochemical properties.
作为本公开实施方式所述方法的可选的技术方案，所述方法包括以下步骤：As an optional technical solution of the method described in the embodiment of the present disclosure, the method includes the following steps:
将SiO或制备SiO的原料及M单质或制备M单质的原料放入真空炉中；Put SiO or the raw material for preparing SiO and M elemental substance or the raw material for preparing M elemental substance into the vacuum furnace;
在1200℃-1600℃、0.5Pa-500Pa的环境下生成M蒸汽与SiO蒸汽；M steam and SiO steam are generated in the environment of 1200℃-1600℃ and 0.5Pa-500Pa;
将所述M蒸汽与SiO蒸汽在置于真空炉内的混合装置中混合均匀，然后进行冷却凝结，得到固相的M与SiO混合的硅复合物；The M steam and the SiO steam are uniformly mixed in a mixing device placed in a vacuum furnace, and then cooled and condensed to obtain a solid-phase M and SiO mixed silicon composite;
对所述硅复合物进行粉碎和分级，制备成粉体材料；pulverizing and classifying the silicon composite to prepare a powder material;
将所述粉体材料进行碳包覆，使硅复合物表面的碳被膜140厚度为50nm-200nm之间，得到硅基负极材料100。The powder material is coated with carbon, so that the thickness of the carbon film 140 on the surface of the silicon composite is between 50 nm and 200 nm to obtain the silicon-based negative electrode material 100 .
III.负极材料及负极III. Negative electrode material and negative electrode
硅基负极材料100可以用作负极活性材料，例如锂离子电池200中的负极活性材料。一实施方式提供了负极材料，负极材料包含上述硅基负极材料100。The silicon-based negative electrode material 100 may be used as a negative electrode active material, such as a negative electrode active material in the lithium ion battery 200 . An embodiment provides a negative electrode material, and the negative electrode material includes the above-mentioned silicon-based negative electrode material 100 .
在一些实施方式中，负极材料包含硅基负极材料100、导电剂和粘结剂。In some embodiments, the negative electrode material includes a silicon-based negative electrode material 100, a conductive agent, and a binder.
在一些实施方式中，负极材料还包含石墨。在一些实施方式中，所述硅基负极材料100与石墨的质量比为1:(6-12)。In some embodiments, the negative electrode material further comprises graphite. In some embodiments, the mass ratio of the silicon-based negative electrode material 100 to graphite is 1:(6-12).
一实施方式提供了制备负极材料的方法，包括：将硅基负极材料100以及导电剂和粘结剂混合。An embodiment provides a method for preparing a negative electrode material, including: mixing a silicon-based negative electrode material 100 with a conductive agent and a binder.
如图12所示，一实施方式提供了负极240，包括硅基负极材料100。As shown in FIG. 12 , an embodiment provides a negative electrode 240 including a silicon-based negative electrode material 100 .
在一些实施方式中，负极包括：负极集流体242以及在负极集流体242上的负极性材料层244，其中，负极性材料层244包含上述负极材料。In some embodiments, the negative electrode includes: a negative electrode current collector 242 and a negative electrode material layer 244 on the negative electrode current collector 242 , wherein the negative electrode material layer 244 includes the above-mentioned negative electrode material.
一实施方式提供了制备负极240的方法，包括：将包括负极材料的浆料涂覆于负极集流体242上。An embodiment provides a method for preparing the negative electrode 240 , including: coating a slurry including a negative electrode material on the negative electrode current collector 242 .
在一些实施方式中，提供了负极，包括：负极集流体242以及在负极集流体242上的负极活性材料层244，其中，负极活性材料层244包含上述硅基负极材料100。在一些实施方式中，负极活性材料层244还包含导电剂和粘结剂。在一些实施方式中，负极活性材料层244还包含石墨。In some embodiments, a negative electrode is provided comprising: a negative electrode current collector 242 and a negative electrode active material layer 244 on the negative electrode current collector 242, wherein the negative electrode active material layer 244 comprises the above-described silicon-based negative electrode material 100. In some embodiments, the anode active material layer 244 further includes a conductive agent and a binder. In some embodiments, the anode active material layer 244 further includes graphite.
在一些实施方式中，硅基负极材料100、导电剂和粘结剂质量比为(70-95):(2-15):(4-10)。在一些实施方式中，硅基负极材料100与石墨的质量比为1:(6-12)。In some embodiments, the mass ratio of the silicon-based negative electrode material 100, the conductive agent and the binder is (70-95):(2-15):(4-10). In some embodiments, the mass ratio of silicon-based anode material 100 to graphite is 1:(6-12).
如图8所示，在一些实施方式中，提供了制备负极240的方法，包括：将包括硅基负极材料100的浆料施加于所述负极集流体242上，以在所述负极集流体242上形成负极活性材料层244；以及干燥所述负极活性材料层244。As shown in FIG. 8 , in some embodiments, a method of preparing a negative electrode 240 is provided, comprising: applying a slurry including a silicon-based negative electrode material 100 on the negative electrode current collector 242 , so that the negative electrode current collector 242 is forming a negative electrode active material layer 244 thereon; and drying the negative electrode active material layer 244 .
在一些实施方式中，干燥可以是真空干燥。一些实施方式中，浆料的总固含量在30％-60％。一些实施方式中，浆料中硅基负极材料100、导电剂和粘结剂的总固含量在30％-60％。一些实施方式中，浆料中硅基负极材料100、导电剂、粘结剂和石墨的总固含量在30％-60％。In some embodiments, drying may be vacuum drying. In some embodiments, the total solids content of the slurry is between 30% and 60%. In some embodiments, the total solid content of the silicon-based negative electrode material 100, the conductive agent and the binder in the slurry is 30%-60%. In some embodiments, the total solid content of the silicon-based negative electrode material 100, the conductive agent, the binder and the graphite in the slurry is 30%-60%.
在一些实施方式中，在将浆料施加于所述负极集流体242上之前，包括以下步骤：将 负极活性材料层244中的各组分(例如硅基负极材料100、导电剂和粘结剂，以及可选的石墨)分散在溶剂中，以形成浆料。In some embodiments, before applying the slurry on the negative electrode current collector 242, the following steps are included: each component in the negative electrode active material layer 244 (eg, the silicon-based negative electrode material 100, the conductive agent and the binder) is mixed , and optionally graphite) dispersed in a solvent to form a slurry.
在一些实施方式中，负极集流体242可以是金属。在一些实施方式中，负极集流体242包括但不限于：铜箔集流体、铝箔集流体中的一种。In some embodiments, the anode current collector 242 may be a metal. In some embodiments, the negative electrode current collector 242 includes, but is not limited to, one of a copper foil current collector and an aluminum foil current collector.
浆料可以包含溶剂。在一些实施方式中，该溶剂包括但不限于为水。The slurry may contain solvent. In some embodiments, the solvent includes, but is not limited to, water.
粘结剂可以改善负极活性物质颗粒彼此以及与集流体242的粘结性质。在一些实施方式中，粘结剂包括非水性粘结剂或水性粘结剂中的至少一种。非水性粘结剂包括但不限于聚氯乙烯、羧化聚氯乙烯、聚氟乙烯、包含亚乙基氧的聚合物、聚乙烯基吡咯烷酮、聚氨酯、聚四氟乙烯、聚偏氟乙烯、聚乙烯、聚丙烯、聚酰胺酰亚胺、或聚酰亚胺中的至少一种。水性粘结剂包括但不限于基于橡胶的粘结剂或者聚合物树脂粘结剂中的至少一种。The binder can improve the bonding properties of the anode active material particles with each other and with the current collector 242 . In some embodiments, the binder includes at least one of a non-aqueous binder or an aqueous binder. Non-aqueous binders include, but are not limited to, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride, polyvinylidene At least one of ethylene, polypropylene, polyamideimide, or polyimide. Aqueous binders include, but are not limited to, at least one of rubber-based binders or polymeric resin binders.
导电剂可以提升电极的导电性。导电剂包括但不限于高导电率的材料，例如为金、铜、镍、铝、银、和/或类似的金属粉末或金属纤维和/或类似的基于金属的材料；或者天然石墨、人造石墨、炭黑、乙炔黑、科琴黑、碳纤维和/或类似的基于碳的材料；或者聚亚苯基衍生物和/或类似的导电聚合物；和/或其混合物。Conductive agents can improve the conductivity of electrodes. Conductive agents include but are not limited to high conductivity materials such as gold, copper, nickel, aluminum, silver, and/or similar metal powders or metal fibers and/or similar metal-based materials; or natural graphite, artificial graphite , carbon black, acetylene black, Ketjen black, carbon fiber and/or similar carbon-based materials; or polyphenylene derivatives and/or similar conductive polymers; and/or mixtures thereof.
IV.锂离子电池IV. Lithium-ion battery
一实施方式提供了锂离子电池200，包含上述的硅基负极材料100。One embodiment provides a lithium-ion battery 200 including the above-described silicon-based negative electrode material 100 .
在一些实施方式中，锂离子电池200包括：In some embodiments, lithium-ion battery 200 includes:
正极220；positive 220;
负极240；以及 negative electrode 240; and
电解液260， Electrolyte 260,
其中，其中，负极240包括负极集流体242和设置在所述负极集流体242上的负极活性材料层244，所述负极活性材料层244包括所述硅基负极材料100。Wherein, the negative electrode 240 includes a negative electrode current collector 242 and a negative electrode active material layer 244 disposed on the negative electrode current collector 242 , and the negative electrode active material layer 244 includes the silicon-based negative electrode material 100 .
如图9所示，在一些实施方式中，锂离子电池200可以包括设置在正极220和负极240之间的隔膜280。隔膜280可以是聚合物微孔膜，例如聚丙烯微孔膜。隔膜280可以是商购的。As shown in FIG. 9 , in some embodiments, the lithium-ion battery 200 may include a separator 280 disposed between the positive electrode 220 and the negative electrode 240 . The membrane 280 may be a polymeric microporous membrane, such as a polypropylene microporous membrane. Septum 280 may be commercially available.
在一些实施方式中，锂离子电池200可以包括外壳290。正极220、负极240、隔膜280、电解液260可以容纳在外壳290中。In some embodiments, the lithium-ion battery 200 may include a housing 290 . The positive electrode 220 , the negative electrode 240 , the separator 280 , and the electrolyte 260 may be accommodated in the case 290 .
在一些实施方式中，锂离子电池可以是圆柱形电池、方形电池或纽扣电池。锂离子电池可以是刚性外壳电池或者软包电池。In some embodiments, the lithium ion battery may be a cylindrical battery, a prismatic battery, or a coin cell battery. Lithium-ion batteries can be rigid case batteries or pouch batteries.
在一些实施方式中，正极220可以包括正极集流体和设置在正极集流体上的正极活性材料层。正极活性材料层包括能够可逆地嵌入和解嵌锂离子的正极活性材料，正极活性材料的实例包括但不限于LiCoO 2、LiNiO 2、LiMnO 2、LiMn 2O 4、锂-过渡金属氧化物中的一种。 In some embodiments, the positive electrode 220 may include a positive electrode current collector and a positive electrode active material layer disposed on the positive electrode current collector. The positive electrode active material layer includes a positive electrode active material capable of reversibly intercalating and deintercalating lithium ions, and examples of the positive electrode active material include, but are not limited to, one of LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , and lithium-transition metal oxides. kind.
一些实施方式中，电解液260包括但不限于非水有机溶剂，例如碳酸酯、酯、醚或酮中的至少一种。一些实施方式中，碳酸酯包括但不限于碳酸二甲酯(DMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸甲乙酯(MEC)、碳酸亚乙酯(EC)、碳酸亚丙酯(PC)或碳酸亚丁酯(BC)中的至少一种。酯包括但不限于丁内酯(BL)、癸内酯、戊内酯(BL)、甲瓦龙酸内酯、己内酯(BC)、乙酸甲酯、乙酸乙酯或乙酸正丙酯中的至少一种。醚包括但不限于可包括二丁基醚。酮包括但不限于聚甲基乙烯基酮。In some embodiments, the electrolyte 260 includes, but is not limited to, a non-aqueous organic solvent, such as at least one of carbonates, esters, ethers, or ketones. In some embodiments, carbonates include, but are not limited to, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC) , at least one of methyl ethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC) or butylene carbonate (BC). Esters include but are not limited to butyrolactone (BL), decanolide, valerolactone (BL), mevalonolactone, caprolactone (BC), methyl acetate, ethyl acetate or n-propyl acetate at least one of. Ethers include, but are not limited to, may include dibutyl ether. Ketones include, but are not limited to, polymethyl vinyl ketone.
与其他方式相比，本公开实施方式具有如下有益效果：Compared with other ways, the embodiments of the present disclosure have the following beneficial effects:
本公开通过控制碳包覆过程的相关参数，获得碳被膜140厚度在50nm-200nm之间的硅基负极材料100，以提高硅复合物的导电性，适宜厚度的碳被膜140包覆硅复合物能够显著提升硅复合物的容量效率和循环性能。In the present disclosure, by controlling the relevant parameters of the carbon coating process, a silicon-based negative electrode material 100 with a carbon film 140 having a thickness of 50 nm-200 nm is obtained, so as to improve the conductivity of the silicon composite, and a carbon film 140 with a suitable thickness coats the silicon composite It can significantly improve the capacity efficiency and cycle performance of the silicon composite.
与其他方式相比，如其他方式仅公开了对复合物进行碳包覆的方式以及通过控制所含碳元素的质量分数来控制碳包覆的程度。但是，对于不同粒度分布以及不同形貌和比表面 积的材料，适宜的包覆量以碳元素的质量分数是不同的。例如，对于比较面积很大的材料，将材料表面均匀且完全的覆盖碳层，需要的碳会非常多，此时仅以碳元素的质量分数进行控制，不可避免的会导致部分颗粒或颗粒的部分位置无法被碳层覆盖或碳层过厚。而本公开实施方式采用了通过控制碳包覆层的厚度来控制碳包覆的程度，可以有效的实现复合物表面无缺陷包覆，电极材料的容量效率及循环性能更加优异。实施方式的制备不仅工艺简单、成本低廉，而且得到的硅基负极材料100应用于锂离子二次电池200具有首次充放电效率高、循环性能好的优点。Compared with other methods, the other methods only disclose the method of carbon coating the composite and control the degree of carbon coating by controlling the mass fraction of the contained carbon element. However, for materials with different particle size distributions as well as different morphologies and specific surface areas, the appropriate coating amount and the mass fraction of carbon are different. For example, for a material with a relatively large area, covering the surface of the material uniformly and completely with a carbon layer requires a lot of carbon. At this time, only the mass fraction of carbon is controlled, which will inevitably lead to some particles or particles. Some locations cannot be covered by the carbon layer or the carbon layer is too thick. However, in the embodiment of the present disclosure, the degree of carbon coating is controlled by controlling the thickness of the carbon coating layer, which can effectively achieve defect-free coating on the surface of the composite, and the capacity efficiency and cycle performance of the electrode material are more excellent. The preparation of the embodiment is not only simple in process and low in cost, but also has the advantages of high initial charge-discharge efficiency and good cycle performance when the obtained silicon-based negative electrode material 100 is applied to the lithium ion secondary battery 200 .
下面将结合具体实施例对本发明的实施方案进行详细描述，但是本领域技术人员将会理解，下列实施例仅用于说明本发明，而不应视为限制本发明的范围。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。The embodiments of the present invention will be described in detail below in conjunction with specific examples, but those skilled in the art will understand that the following examples are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market.
实施例Example
实施例1Example 1
本实施例提供一种硅基负极材料100及其制备方法，所述硅基负极材料100包括内核120和覆盖所述内核120表面的碳被膜140，所述内核120包含硅、硅氧化物及硅酸镁，所述碳被膜140的厚度为100nm，以所述负极材料的总质量为100％计，Mg元素的质量分数为15％。This embodiment provides a silicon-based negative electrode material 100 and a preparation method thereof. The silicon-based negative electrode material 100 includes an inner core 120 and a carbon coating 140 covering the surface of the inner core 120 , and the inner core 120 includes silicon, silicon oxide and silicon. Magnesium oxide, the thickness of the carbon film 140 is 100 nm, and the mass fraction of Mg element is 15% based on the total mass of the negative electrode material as 100%.
所述硅基负极材料100通过如下方法制备：The silicon-based negative electrode material 100 is prepared by the following method:
硅复合物的合成Synthesis of Silicon Complexes
(1)取5kg硅粉(其化学组成为Si)，10kg硅微粉(其化学组成为SiO 2)，使用VC混合机混合30min后得到SiO原料，投入真空炉反应室靠近炉尾的一端； (1) get 5kg silicon powder (its chemical composition is Si), 10kg silicon micropowder (its chemical composition is SiO 2 ), obtain SiO raw material after using VC mixer to mix 30min, drop into one end of vacuum furnace reaction chamber close to the furnace tail;
(2)取2kg镁粉，投入真空炉反应室靠近炉口的一端；(2) get 2kg magnesium powder, put into the vacuum furnace reaction chamber near the end of the furnace mouth;
(3)在冷凝室内置入收集装置，在真空条件下加热到1300℃使炉内生成SiO蒸汽和Mg蒸汽，通过混合装置后混合均匀的气态混合物在冷凝室内冷却后得到硅复合物(包括Si、SiO及硅酸镁)，反应结束后对设备进行冷却并收集到产物11kg。(3) A collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite (including Si , SiO and magnesium silicate), after the reaction, the equipment was cooled and 11 kg of product was collected.
负极材料的制备Preparation of Anode Materials
(1)将本实施例制得的硅复合物5kg，经破碎、球磨、分级等工艺将其粒度(D50)控制在4μm。(1) 5kg of the silicon composite prepared in this example was crushed, ball milled, classified and other processes to control its particle size (D50) at 4 μm.
(2)将上述4μm的硅复合物置于CVD炉内，内外路均通入氮气作保护气，加热到950℃时内路以1.5L/min的流量通入甲烷气体作为碳源，通入甲烷气体的时间为10h，在硅复合物表面包覆厚度为100nm的碳被膜140。(2) Place the above-mentioned 4 μm silicon composite in a CVD furnace, and feed nitrogen into the inner and outer circuits as protective gas. When heated to 950° C., methane gas is introduced into the inner circuit at a flow rate of 1.5 L/min as a carbon source, and methane is introduced into it. The gas time was 10 hours, and the surface of the silicon composite was covered with a carbon film 140 with a thickness of 100 nm.
(3)包覆完成后，将得到的材料置于辊道窑内960℃下进行高温碳化，以得到稳定的硅复合物负极材料。(3) After the coating is completed, the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
实施例2Example 2
本实施例提供一种硅基负极材料100及其制备方法，所述硅基负极材料100包括内核120和覆盖所述内核120表面的碳被膜140，所述内核120包含硅、硅氧化物及硅酸镁，所述碳被膜140的厚度为200nm，以所述负极材料的总质量为100％计，Mg元素的质量分数为15％。This embodiment provides a silicon-based negative electrode material 100 and a preparation method thereof. The silicon-based negative electrode material 100 includes an inner core 120 and a carbon coating 140 covering the surface of the inner core 120 , and the inner core 120 includes silicon, silicon oxide and silicon. Magnesium oxide, the thickness of the carbon coating 140 is 200 nm, and the mass fraction of Mg element is 15% based on the total mass of the negative electrode material as 100%.
所述硅基负极材料100通过如下方法制备：The silicon-based negative electrode material 100 is prepared by the following method:
硅复合物的合成Synthesis of Silicon Complexes
(1)取5kg硅粉(其化学组成为Si)，10kg硅微粉(其化学组成为SiO 2)，使用VC混合机混合30min后得到SiO原料，投入真空炉反应室靠近炉尾的一端； (1) get 5kg silicon powder (its chemical composition is Si), 10kg silicon micropowder (its chemical composition is SiO 2 ), obtain SiO raw material after using VC mixer to mix 30min, drop into one end of vacuum furnace reaction chamber close to the furnace tail;
(2)取2kg镁粉，投入真空炉反应室靠近炉口的一端；(2) get 2kg magnesium powder, put into the vacuum furnace reaction chamber near the end of the furnace mouth;
(3)在冷凝室内置入收集装置，在真空条件下加热到1300℃使炉内生成SiO蒸汽和Mg 蒸汽，通过混合装置后混合均匀的气态混合物在冷凝室内冷却后得到硅复合物(包括Si、SiO及硅酸镁)，反应结束后对设备进行冷却并收集到产物11kg。(3) A collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite (including Si , SiO and magnesium silicate), after the reaction, the equipment was cooled and 11 kg of product was collected.
负极材料的制备Preparation of Anode Materials
(1)取通过本公开方法制得的硅复合物5kg，经破碎、球磨、分级等工艺将其粒度(D50)控制在4μm。(1) Take 5 kg of the silicon composite prepared by the method of the present disclosure, and control its particle size (D50) to be 4 μm through processes such as crushing, ball milling, and classification.
(2)在VC混合机内以900r/min的转速将上述4μm的硅复合物2kg与260g沥青混合1h，然后置于氩气氛保护的辊道窑内，加热到950℃时内保温2h，在硅复合物表面包覆厚度为200nm的碳被膜140。(2) Mix 2kg of the above-mentioned 4μm silicon composite with 260g pitch in a VC mixer at a speed of 900r/min for 1h, then place it in a roller kiln protected by an argon atmosphere, and keep it at 950°C for 2h. The surface of the silicon composite is covered with a carbon film 140 having a thickness of 200 nm.
(3)包覆完成后，将得到的材料置于辊道窑内960℃下进行高温碳化，以得到稳定的硅复合物负极材料。(3) After the coating is completed, the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
实施例3Example 3
本实施例提供一种硅基负极材料100及其制备方法，所述硅基负极材料100包括内核120和覆盖所述内核120表面的碳被膜140，所述内核120包含硅、硅氧化物及硅酸镁，所述碳被膜140的厚度为200nm，以所述负极材料的总质量为100％计，Mg元素的质量分数为9.5％。This embodiment provides a silicon-based negative electrode material 100 and a preparation method thereof. The silicon-based negative electrode material 100 includes an inner core 120 and a carbon coating 140 covering the surface of the inner core 120 , and the inner core 120 includes silicon, silicon oxide and silicon. Magnesium oxide, the thickness of the carbon coating 140 is 200 nm, and the mass fraction of Mg element is 9.5% based on the total mass of the negative electrode material as 100%.
所述硅基负极材料100通过如下方法制备：The silicon-based negative electrode material 100 is prepared by the following method:
硅复合物的合成Synthesis of Silicon Complexes
(1)取5kg硅粉(其化学组成为Si)，10kg硅微粉(其化学组成为SiO 2)，使用VC混合机混合30min后得到SiO原料，投入真空炉反应室靠近炉尾的一端； (1) get 5kg silicon powder (its chemical composition is Si), 10kg silicon micropowder (its chemical composition is SiO 2 ), obtain SiO raw material after using VC mixer to mix 30min, drop into one end of vacuum furnace reaction chamber close to the furnace tail;
(2)取1.2kg镁粉，投入真空炉反应室靠近炉口的一端；(2) Take 1.2kg of magnesium powder and put it into one end of the vacuum furnace reaction chamber close to the furnace mouth;
(3)在冷凝室内置入收集装置，在真空条件下加热到1300℃使炉内生成SiO蒸汽和Mg蒸汽，通过混合装置后混合均匀的气态混合物在冷凝室内冷却后得到硅复合物(包括Si、SiO及硅酸镁)，反应结束后对设备进行冷却并收集到产物10kg。(3) A collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite (including Si , SiO and magnesium silicate), after the reaction, the equipment was cooled and 10kg of product was collected.
负极材料的制备Preparation of Anode Materials
(1)取通过本公开方法制得的硅复合物5kg，经破碎、球磨、分级等工艺将其粒度(D50)控制在4μm。(1) Take 5 kg of the silicon composite prepared by the method of the present disclosure, and control its particle size (D50) to be 4 μm through processes such as crushing, ball milling, and classification.
(2)将上述4μm的硅复合物置于CVD炉内，内外路均通入氮气作保护气，加热到950℃时内路以1.5L/min的流量通入甲烷气体作为碳源，通入甲烷气体的时间为16h，在硅复合物表面包覆厚度为200nm的碳被膜140。(2) Place the above-mentioned 4 μm silicon composite in a CVD furnace, and feed nitrogen into the inner and outer circuits as protective gas. When heated to 950° C., methane gas is introduced into the inner circuit at a flow rate of 1.5 L/min as a carbon source, and methane is introduced into it. The gas time was 16 hours, and the surface of the silicon composite was covered with a carbon film 140 with a thickness of 200 nm.
(3)包覆完成后，将得到的材料置于辊道窑内960℃下进行高温碳化，以得到稳定的硅复合物负极材料。(3) After the coating is completed, the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
实施例4Example 4
本实施例提供一种硅基负极材料100及其制备方法，所述硅基负极材料100包括内核120和覆盖所述内核120表面的碳被膜140，所述内核120包含硅、硅氧化物及硅酸钙，所述碳被膜140的厚度为160nm，以所述负极材料的总质量为100％计，Ca元素的质量分数为8％。This embodiment provides a silicon-based negative electrode material 100 and a preparation method thereof. The silicon-based negative electrode material 100 includes an inner core 120 and a carbon coating 140 covering the surface of the inner core 120 , and the inner core 120 includes silicon, silicon oxide and silicon. calcium acid, the thickness of the carbon coating 140 is 160 nm, and the mass fraction of Ca element is 8% based on the total mass of the negative electrode material as 100%.
所述硅基负极材料100通过如下方法制备：The silicon-based negative electrode material 100 is prepared by the following method:
硅复合物的合成Synthesis of Silicon Complexes
(1)取5kg硅粉(其化学组成为Si)，10kg硅微粉(其化学组成为SiO 2)，使用VC混合机混合30min后得到SiO原料，投入真空炉反应室靠近炉尾的一端； (1) get 5kg silicon powder (its chemical composition is Si), 10kg silicon micropowder (its chemical composition is SiO 2 ), obtain SiO raw material after using VC mixer to mix 30min, drop into one end of vacuum furnace reaction chamber close to the furnace tail;
(2)取1kg金属钙块体，置于真空炉反应室靠近炉口的一端；(2) get 1kg of metal calcium block, and place it on one end of the vacuum furnace reaction chamber close to the furnace mouth;
(3)在冷凝室内置入收集装置，在真空条件下加热到1300℃使炉内生成SiO蒸汽和Ca蒸汽，通过混合装置后混合均匀的气态混合物在冷凝室内冷却后得到硅复合物(包括Si、SiO及硅酸钙)，反应结束后对设备进行冷却并收集到产物8.8kg。(3) A collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Ca vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite (including Si , SiO and calcium silicate), after the reaction, the equipment was cooled and 8.8kg of product was collected.
负极材料的制备Preparation of Anode Materials
(1)取通过本公开方法制得的硅复合物5kg，经破碎、球磨、分级等工艺将其粒度(D50)控制在4μm。(1) Take 5 kg of the silicon composite prepared by the method of the present disclosure, and control its particle size (D50) to be 4 μm through processes such as crushing, ball milling, and classification.
(2)将上述4μm的硅复合物置于CVD炉内，内外路均通入氮气作保护气，加热到950℃时内路以1.5L/min的流量通入甲烷气体作为碳源，通入甲烷气体的时间为15h，在硅复合物表面包覆厚度为160nm的碳被膜140。(2) Place the above-mentioned 4 μm silicon composite in a CVD furnace, and feed nitrogen into the inner and outer circuits as protective gas. When heated to 950° C., methane gas is introduced into the inner circuit at a flow rate of 1.5 L/min as a carbon source, and methane is introduced into it. The gas time was 15 hours, and the surface of the silicon composite was covered with a carbon film 140 with a thickness of 160 nm.
(3)包覆完成后，将得到的材料置于辊道窑内960℃下进行高温碳化，以得到稳定的硅复合物负极材料。(3) After the coating is completed, the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
实施例5Example 5
本实施例提供一种硅基负极材料100及其制备方法，所述硅基负极材料100包括内核120和覆盖所述内核120表面的碳被膜140，所述内核120包含硅、硅氧化物及硅酸钙，所述碳被膜140的厚度为130nm，以所述负极材料的总质量为100％计，Ca元素的质量分数为9％。This embodiment provides a silicon-based negative electrode material 100 and a preparation method thereof. The silicon-based negative electrode material 100 includes an inner core 120 and a carbon coating 140 covering the surface of the inner core 120 , and the inner core 120 includes silicon, silicon oxide and silicon. Calcium acid, the thickness of the carbon coating 140 is 130 nm, and the mass fraction of Ca element is 9% based on the total mass of the negative electrode material as 100%.
所述硅基负极材料100通过如下方法制备：The silicon-based negative electrode material 100 is prepared by the following method:
硅复合物的合成Synthesis of Silicon Complexes
(1)取5kg硅粉(其化学组成为Si)，10kg硅微粉(其化学组成为SiO 2)，使用VC混合机混合30min后得到SiO原料，投入真空炉反应室靠近炉尾的一端； (1) get 5kg silicon powder (its chemical composition is Si), 10kg silicon micropowder (its chemical composition is SiO 2 ), obtain SiO raw material after using VC mixer to mix 30min, drop into one end of vacuum furnace reaction chamber close to the furnace tail;
(2)取1kg金属钙块体，置于真空炉反应室靠近炉口的一端；(2) get 1kg of metal calcium block, and place it on one end of the vacuum furnace reaction chamber close to the furnace mouth;
(3)在冷凝室内置入收集装置，在真空条件下加热到1350℃使炉内生成SiO蒸汽和Ca蒸汽，通过混合装置后混合均匀的气态混合物在冷凝室内冷却后得到硅复合物(包括Si、SiO及硅酸钙)，反应结束后对设备进行冷却并收集到产物9.6kg。(3) A collection device is installed in the condensation chamber, heated to 1350 ° C under vacuum conditions to generate SiO vapor and Ca vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite (including Si , SiO and calcium silicate), after the reaction, the equipment was cooled and 9.6kg of product was collected.
负极材料的制备Preparation of Anode Materials
(1)取通过本公开方法制得的硅复合物5kg，经破碎、球磨、分级等工艺将其粒度(D50)控制在4μm。(1) Take 5 kg of the silicon composite prepared by the method of the present disclosure, and control its particle size (D50) to be 4 μm through processes such as crushing, ball milling, and classification.
(2)将上述4μm的硅复合物置于CVD炉内，内外路均通入氮气作保护气，加热到950℃时内路以1.5L/min的流量通入甲烷气体作为碳源，通入甲烷气体的时间为13.5h，在硅复合物表面包覆厚度为130nm的碳被膜140。(2) Place the above-mentioned 4 μm silicon composite in a CVD furnace, and feed nitrogen into the inner and outer circuits as protective gas. When heated to 950° C., methane gas is introduced into the inner circuit at a flow rate of 1.5 L/min as a carbon source, and methane is introduced into it. The gas time was 13.5 hours, and the carbon film 140 with a thickness of 130 nm was coated on the surface of the silicon composite.
(3)包覆完成后，将得到的材料置于辊道窑内960℃下进行高温碳化，以得到稳定的硅复合物负极材料。(3) After the coating is completed, the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
实施例6Example 6
本实施例提供一种硅基负极材料100及其制备方法，所述硅基负极材料100包括内核120和覆盖所述内核120表面的碳被膜140，所述内核120包含硅、硅氧化物及硅酸镁，所述碳被膜140的厚度为50nm，以所述负极材料的总质量为100％计，Mg元素的质量分数为15％。This embodiment provides a silicon-based negative electrode material 100 and a preparation method thereof. The silicon-based negative electrode material 100 includes an inner core 120 and a carbon coating 140 covering the surface of the inner core 120 , and the inner core 120 includes silicon, silicon oxide and silicon. Magnesium oxide, the thickness of the carbon coating 140 is 50 nm, and the mass fraction of Mg element is 15% based on the total mass of the negative electrode material as 100%.
所述硅基负极材100料通过如下方法制备：The silicon-based negative material 100 is prepared by the following method:
硅复合物的合成Synthesis of Silicon Complexes
(1)取5kg硅粉(其化学组成为Si)，10kg硅微粉(其化学组成为SiO 2)，使用VC混合机混合30min后得到SiO原料，投入真空炉反应室靠近炉尾的一端； (1) get 5kg silicon powder (its chemical composition is Si), 10kg silicon micropowder (its chemical composition is SiO 2 ), obtain SiO raw material after using VC mixer to mix 30min, drop into one end of vacuum furnace reaction chamber close to the furnace tail;
(2)取2kg镁粉，投入真空炉反应室靠近炉口的一端；(2) get 2kg magnesium powder, put into the vacuum furnace reaction chamber near the end of the furnace mouth;
(3)在冷凝室内置入收集装置，在真空条件下加热到1300℃使炉内生成SiO蒸汽和Mg蒸汽，通过混合装置后混合均匀的气态混合物在冷凝室内冷却后得到硅复合物(包括Si、SiO及硅酸镁)，反应结束后对设备进行冷却并收集到产物11kg。(3) A collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite (including Si , SiO and magnesium silicate), after the reaction, the equipment was cooled and 11 kg of product was collected.
负极材料的制备Preparation of Anode Materials
(1)取通过本公开方法制得的硅复合物5kg，经破碎、球磨、分级等工艺将其粒度(D50) 控制在4μm。(1) Take 5 kg of the silicon composite prepared by the method of the present disclosure, and control its particle size (D50) at 4 μm through processes such as crushing, ball milling, and classification.
(2)将上述4μm的硅复合物置于CVD炉内，内外路均通入氮气作保护气，加热到950℃时内路以1.5L/min的流量通入甲烷气体作为碳源，通入甲烷气体的时间为6h，在硅复合物表面包覆厚度为50nm的碳被膜140。(2) Place the above-mentioned 4 μm silicon composite in a CVD furnace, and feed nitrogen into the inner and outer circuits as protective gas. When heated to 950° C., methane gas is introduced into the inner circuit at a flow rate of 1.5 L/min as a carbon source, and methane is introduced into it. The gas time was 6 hours, and the carbon film 140 with a thickness of 50 nm was coated on the surface of the silicon composite.
(3)包覆完成后，将得到的材料置于辊道窑内960℃下进行高温碳化，以得到稳定的硅复合物负极材料。实施例7(3) After the coating is completed, the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material. Example 7
除了在硅复合物的合成中，将(1)取5kg硅粉(其化学组成为Si)，10kg硅微粉(其化学组成为SiO 2)，使用VC混合机混合30min后得到SiO原料，投入真空炉反应室靠近炉口的一端； Except in the synthesis of silicon compound, (1) take 5kg silicon powder (its chemical composition is Si), 10kg silicon micropowder (its chemical composition is SiO 2 ), use a VC mixer to mix for 30min to obtain SiO raw materials, put into vacuum One end of the furnace reaction chamber close to the furnace mouth;
(2)取2kg镁粉，投入真空炉反应室靠近炉尾的一端；(2) get 2kg magnesium powder, put into the vacuum furnace reaction chamber near the end of the furnace tail;
其他硅复合物的合成步骤(3)、负极材料的制备步骤(1)-(3)均与实施例1相同。The synthesis steps (3) of other silicon composites and the preparation steps (1)-(3) of the negative electrode material are the same as those in Example 1.
对比例1Comparative Example 1
硅复合物的合成Synthesis of Silicon Complexes
(1)取5kg硅粉，10kg硅微粉，使用VC混合机混合30min后得到SiO原料，投入真空炉反应室靠近炉尾的一端；(1) get 5kg silicon powder, 10kg silicon micropowder, obtain SiO raw material after using VC mixer to mix 30min, drop into one end of vacuum furnace reaction chamber close to the furnace tail;
(2)取2kg镁粉，投入真空炉反应室靠近炉口的一端；(2) get 2kg magnesium powder, put into the vacuum furnace reaction chamber near the end of the furnace mouth;
(3)在冷凝室内置入收集装置，在真空条件下加热到1300℃使炉内生成SiO蒸汽和Mg蒸汽，通过混合装置后混合均匀的气态混合物在冷凝室内冷却后得到硅复合物，反应结束后对设备进行冷却并收集到产物11kg。(3) A collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite, and the reaction is completed. The equipment was then cooled and 11 kg of product was collected.
负极材料的制备Preparation of Anode Materials
(1)取通过本公开方法制得的硅复合物5kg，经破碎、球磨、分级等工艺将其粒度(D50)控制在4μm。(1) Take 5 kg of the silicon composite prepared by the method of the present disclosure, and control its particle size (D50) to be 4 μm through processes such as crushing, ball milling, and classification.
(2)将上述4μm的硅复合物置于CVD炉内，内外路均通入氮气作保护气，加热到950℃时内路以2L/min的流量通入甲烷气体作为碳源，通入甲烷气体的时间为2h，在硅复合物表面包覆厚度为30nm的碳被膜。(2) The above-mentioned 4 μm silicon composite is placed in a CVD furnace, and nitrogen gas is introduced into the inner and outer circuits as protective gas. When heated to 950 ° C, methane gas is introduced into the inner circuit at a flow rate of 2 L/min as a carbon source, and methane gas is introduced into it. The time is 2h, and a carbon film with a thickness of 30nm is coated on the surface of the silicon composite.
(3)包覆完成后，将得到的材料置于辊道窑内960℃下进行高温碳化，以得到稳定的硅复合物负极材料。对比例2(3) After the coating is completed, the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material. Comparative Example 2
硅复合物的合成Synthesis of Silicon Complexes
(1)取5kg硅粉，10kg硅微粉，使用VC混合机混合30min后得到SiO原料，投入真空炉反应室靠近炉尾的一端；(1) get 5kg silicon powder, 10kg silicon micropowder, obtain SiO raw material after using VC mixer to mix 30min, drop into one end of vacuum furnace reaction chamber close to the furnace tail;
(2)取2kg镁粉，投入真空炉反应室靠近炉口的一端；(2) get 2kg magnesium powder, put into the vacuum furnace reaction chamber near the end of the furnace mouth;
(3)在冷凝室内置入收集装置，在真空条件下加热到1300℃使炉内生成SiO蒸汽和Mg蒸汽，通过混合装置后混合均匀的气态混合物在冷凝室内冷却后得到硅复合物，反应结束后对设备进行冷却并收集到产物11kg。(3) A collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite, and the reaction is completed. The equipment was then cooled and 11 kg of product was collected.
负极材料的制备Preparation of Anode Materials
(1)取通过本公开方法制得的硅复合物5kg，经破碎、球磨、分级等工艺将其粒度(D50)控制在4μm。(1) Take 5 kg of the silicon composite prepared by the method of the present disclosure, and control its particle size (D50) to be 4 μm through processes such as crushing, ball milling, and classification.
(2)将上述4μm的硅复合物置于CVD炉内，内外路均通入氮气作保护气，加热到950℃时内路以2L/min的流量通入甲烷气体作为碳源，通入甲烷气体的时间为20h，在硅复合物表面包覆厚度为260nm的碳被膜。(2) The above-mentioned 4 μm silicon composite is placed in a CVD furnace, and nitrogen gas is introduced into the inner and outer circuits as protective gas. When heated to 950 ° C, methane gas is introduced into the inner circuit at a flow rate of 2 L/min as a carbon source, and methane gas is introduced into it. The time is 20h, and a carbon film with a thickness of 260nm is coated on the surface of the silicon composite.
(3)包覆完成后，将得到的材料置于辊道窑内960℃下进行高温碳化，以得到稳定的硅复合物负极材料。(3) After the coating is completed, the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
对比例3Comparative Example 3
硅复合物的合成Synthesis of Silicon Complexes
(1)取5kg硅粉，10kg硅微粉，使用VC混合机混合30min后得到SiO原料，投入真空炉反应室靠近炉尾的一端；(1) get 5kg silicon powder, 10kg silicon micropowder, obtain SiO raw material after using VC mixer to mix 30min, drop into one end of the vacuum furnace reaction chamber close to the furnace tail;
(2)取2kg镁粉，投入真空炉反应室靠近炉口的一端；(2) get 2kg magnesium powder, put into the vacuum furnace reaction chamber near the end of the furnace mouth;
(3)在冷凝室内置入收集装置，在真空条件下加热到1300℃使炉内生成SiO蒸汽和Mg蒸汽，通过混合装置后混合均匀的气态混合物在冷凝室内冷却后得到硅复合物，反应结束后对设备进行冷却并收集到产物11kg。(3) A collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite, and the reaction is completed. The equipment was then cooled and 11 kg of product was collected.
负极材料的制备Preparation of Anode Materials
(1)取通过本公开方法制得的硅复合物5kg，经破碎、球磨、分级等工艺将其粒度(D50)控制在4μm。(1) Take 5 kg of the silicon composite prepared by the method of the present disclosure, and control its particle size (D50) to be 4 μm through processes such as crushing, ball milling, and classification.
(2)在VC混合机内以900r/min的转速将上述4μm的硅复合物2kg与50g沥青混合1h，然后置于氩气氛保护的辊道窑内，加热到950℃时内保温2h，在硅复合物表面包覆厚度为20nm的碳被膜。(2) Mix 2kg of the above-mentioned 4μm silicon compound with 50g of pitch in a VC mixer at a speed of 900r/min for 1h, then place it in a roller kiln protected by an argon atmosphere, and keep it at 950°C for 2h. The surface of the silicon composite was covered with a carbon film with a thickness of 20 nm.
(3)包覆完成后，将得到的材料置于辊道窑内960℃下进行高温碳化，以得到稳定的硅复合物负极材料。(3) After the coating is completed, the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
对比例4Comparative Example 4
硅复合物的合成Synthesis of Silicon Complexes
(1)取5kg硅粉，10kg硅微粉，使用VC混合机混合30min后得到SiO原料，投入真空炉反应室靠近炉尾的一端；(1) get 5kg silicon powder, 10kg silicon micropowder, obtain SiO raw material after using VC mixer to mix 30min, drop into one end of vacuum furnace reaction chamber close to the furnace tail;
(2)取2kg镁粉，投入真空炉反应室靠近炉口的一端；(2) get 2kg magnesium powder, put into the vacuum furnace reaction chamber near the end of the furnace mouth;
(3)在冷凝室内置入收集装置，在真空条件下加热到1300℃使炉内生成SiO蒸汽和Mg蒸汽，通过混合装置后混合均匀的气态混合物在冷凝室内冷却后得到硅复合物，反应结束后对设备进行冷却并收集到产物11kg。(3) A collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite, and the reaction is completed. The equipment was then cooled and 11 kg of product was collected.
负极材料的制备Preparation of Anode Materials
(1)取通过本公开方法制得的硅复合物5kg，经破碎、球磨、分级等工艺将其粒度(D50)控制在4μm。(1) Take 5 kg of the silicon composite prepared by the method of the present disclosure, and control its particle size (D50) to be 4 μm through processes such as crushing, ball milling, and classification.
(2)在VC混合机内以900r/min的转速将上述4μm的硅复合物2kg与500g沥青混合1h，然后置于氩气氛保护的辊道窑内，加热到950℃时内保温2h，在硅复合物表面包覆厚度为300nm的碳被膜。(2) Mix 2kg of the above-mentioned 4μm silicon composite with 500g pitch in a VC mixer at a speed of 900r/min for 1h, then place it in a roller kiln protected by an argon atmosphere, and keep it for 2h when heated to 950°C. The surface of the silicon composite was covered with a carbon film with a thickness of 300 nm.
(3)包覆完成后，将得到的材料置于辊道窑内960℃下进行高温碳化，以得到稳定的硅复合物负极材料。(3) After the coating is completed, the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
对比例5Comparative Example 5
本对比例中的硅基负极材料包括内核120和覆盖在内核120表面的碳被膜，内核120包含硅、硅氧化物及硅酸镁，碳被膜的厚度为100nm，以负极材料的总质量为100％计，Mg元素的质量分数为0.5％。The silicon-based negative electrode material in this comparative example includes an inner core 120 and a carbon film covering the surface of the inner core 120. The inner core 120 includes silicon, silicon oxide and magnesium silicate, the thickness of the carbon film is 100 nm, and the total mass of the negative electrode material is 100 nm. %, the mass fraction of Mg element is 0.5%.
硅复合物的合成Synthesis of Silicon Complexes
(1)取5kg硅粉(其化学组成为Si)，10kg硅微粉(其化学组成为SiO 2)，使用VC混合机混合30min后得到SiO原料，投入真空炉反应室靠近炉尾的一端； (1) get 5kg silicon powder (its chemical composition is Si), 10kg silicon micropowder (its chemical composition is SiO 2 ), obtain SiO raw material after using VC mixer to mix 30min, drop into one end of vacuum furnace reaction chamber close to the furnace tail;
(2)取0.05kg镁粉，投入真空炉反应室靠近炉口的一端；(2) Get 0.05kg magnesium powder and put it into one end of the vacuum furnace reaction chamber close to the furnace mouth;
(3)在冷凝室内置入收集装置，在真空条件下加热到1300℃使炉内生成SiO蒸汽和Mg蒸汽，通过混合装置后混合均匀的气态混合物在冷凝室内冷却后得到硅复合物，反应结束后对设备进行冷却并收集到产物9.8kg。(3) A collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite, and the reaction is completed. The equipment was then cooled and 9.8 kg of product were collected.
负极材料的制备Preparation of Anode Materials
(1)取通过本公开方法制得的硅复合物5kg，经破碎、球磨、分级等工艺将其粒度(D50)控制在4μm。(1) Take 5 kg of the silicon composite prepared by the method of the present disclosure, and control its particle size (D50) to be 4 μm through processes such as crushing, ball milling, and classification.
(2)将上述4μm的硅复合物置于CVD炉内，内外路均通入氮气作保护气，加热到950℃时内路以1.5L/min的流量通入甲烷气体作为碳源，通入甲烷气体的时间为9.5h，在硅复合物表面包覆厚度为100nm的碳被膜。(2) The above-mentioned 4 μm silicon composite is placed in a CVD furnace, and nitrogen is introduced into the inner and outer circuits as protective gas. When heated to 950 ° C, methane gas is introduced into the inner circuit at a flow rate of 1.5 L/min as a carbon source, and methane is introduced into it. The gas time was 9.5 hours, and a carbon film with a thickness of 100 nm was coated on the surface of the silicon composite.
(3)包覆完成后，将得到的材料置于辊道窑内960℃下进行高温碳化，以得到稳定的硅复合物负极材料。(3) After the coating is completed, the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
对比例6Comparative Example 6
本对比例中的硅基负极材料包括内核和覆盖在内核表面的碳被膜，内核包含硅、硅氧化物及硅酸镁，碳被膜的厚度为100nm，以负极材料的总质量为100％计，Mg元素的质量分数为35％。The silicon-based negative electrode material in this comparative example includes an inner core and a carbon film covering the surface of the inner core. The inner core contains silicon, silicon oxide and magnesium silicate, and the thickness of the carbon film is 100 nm. The mass fraction of Mg element is 35%.
硅复合物的合成Synthesis of Silicon Complexes
(1)取5kg硅粉(其化学组成为Si)，10kg硅微粉(其化学组成为SiO 2)，使用VC混合机混合30min后得到SiO原料，投入真空炉反应室靠近炉尾的一端； (1) get 5kg silicon powder (its chemical composition is Si), 10kg silicon micropowder (its chemical composition is SiO 2 ), obtain SiO raw material after using VC mixer to mix 30min, drop into one end of vacuum furnace reaction chamber close to the furnace tail;
(2)取6kg镁粉，投入真空炉反应室靠近炉口的一端；(2) get 6kg magnesium powder, put into the vacuum furnace reaction chamber near the end of the furnace mouth;
(3)在冷凝室内置入收集装置，在真空条件下加热到1300℃使炉内生成SiO蒸汽和Mg蒸汽，通过混合装置后混合均匀的气态混合物在冷凝室内冷却后得到硅复合物，反应结束后对设备进行冷却并收集到产物15kg。(3) A collection device is installed in the condensation chamber, heated to 1300 ° C under vacuum conditions to generate SiO vapor and Mg vapor in the furnace, and the uniformly mixed gaseous mixture after passing through the mixing device is cooled in the condensation chamber to obtain a silicon composite, and the reaction is completed. The equipment was then cooled and 15 kg of product was collected.
负极材料的制备Preparation of Anode Materials
(1)取通过本公开方法制得的硅复合物5kg，经破碎、球磨、分级等工艺将其粒度(D50)控制在4μm。(1) Take 5 kg of the silicon composite prepared by the method of the present disclosure, and control its particle size (D50) to be 4 μm through processes such as crushing, ball milling, and classification.
(2)将上述4μm的硅复合物置于CVD炉内，内外路均通入氮气作保护气，加热到950℃时内路以1.5L/min的流量通入甲烷气体作为碳源，通入甲烷气体的时间为10.8h，在硅复合物表面包覆厚度为100nm的碳被膜。(2) Place the above-mentioned 4 μm silicon composite in a CVD furnace, and feed nitrogen into the inner and outer circuits as protective gas. When heated to 950° C., methane gas is introduced into the inner circuit at a flow rate of 1.5 L/min as a carbon source, and methane is introduced into it. The gas time was 10.8 h, and a carbon film with a thickness of 100 nm was coated on the surface of the silicon composite.
(3)包覆完成后，将得到的材料置于辊道窑内960℃下进行高温碳化，以得到稳定的硅复合物负极材料。(3) After the coating is completed, the obtained material is placed in a roller kiln at 960° C. for high temperature carbonization to obtain a stable silicon composite negative electrode material.
性能测试：Performance Testing:
一、形貌测试：1. Appearance test:
使用日立E-3500离子研磨机将制得的硅复合物负极材料颗粒切开，在日立S-4800型冷场发射扫描电镜上观测其截面的形貌结构，结果如图1至图6所示。The prepared silicon composite anode material particles were cut with a Hitachi E-3500 ion mill, and the morphology and structure of the cross-section were observed on a Hitachi S-4800 cold field emission scanning electron microscope. The results are shown in Figures 1 to 6.
图1为实施例1中硅复合物负极材料颗粒截面的电镜照片。由图1可以看出，.材料的内核120部分形成的是均匀的均相结构，质地均匀，由此可以说明实施方式中的实施例1中的硅、硅氧化物及M的硅酸盐三者为均相的状态，且三者均为混合均匀分布。同时可以看出，外部深色部分为碳包覆层。FIG. 1 is an electron microscope photograph of the cross section of the silicon composite negative electrode material particle in Example 1. FIG. It can be seen from FIG. 1 that the inner core 120 of the material forms a uniform homogeneous structure with a uniform texture, which can illustrate the silicon, silicon oxide and M silicate three in Example 1 of the embodiment. The former is a homogeneous state, and the three are mixed and uniformly distributed. At the same time, it can be seen that the outer dark part is a carbon coating.
图2为实施例2中硅复合物负极材料颗粒截面的电镜照片。由图2可以看出，该材料内核120同样质地均匀，由此也可以实施例2中的硅、硅氧化物及M的硅酸盐三者同样呈现出混合均匀的状态。同时可以看出，外部深色部分为碳包覆层。FIG. 2 is an electron microscope photograph of the cross section of the silicon composite negative electrode material particle in Example 2. FIG. It can be seen from FIG. 2 that the core 120 of the material is also uniform in texture, so that the silicon, silicon oxide and silicate of M in Example 2 also show a state of uniform mixing. At the same time, it can be seen that the outer dark part is a carbon coating.
图3为对比例1中硅复合物负极材料颗粒截面的电镜照片。由图3可以看出，其碳包覆层厚度较实施例1和2更薄。FIG. 3 is an electron microscope photograph of the cross section of the silicon composite negative electrode material particle in Comparative Example 1. FIG. It can be seen from FIG. 3 that the thickness of the carbon cladding layer is thinner than that of Examples 1 and 2.
图4为对比例2中硅复合物负极材料颗粒截面的电镜照片。由图4可以看出，其碳包覆层厚度较实施例1和2更厚。图5为对比例3中硅复合物负极材料颗粒截面的电镜照片。由图5可以看出，其碳包覆层厚度较实施例1和2更薄。图6为对比例4中硅复合物负极材料颗粒截面的电镜照片。由图6可以看出，其碳包覆层厚度较实施例1和2更厚。同时内核呈现出多个小微粒状的形态，由此可以看出，在分布复合物中的M含量高于30％时，过量的M会与SiO快速反应并放出大量的热量，导致生成的Si的晶粒极大，因此呈现出内核分布不均匀的表象。FIG. 4 is an electron microscope photograph of the cross section of the silicon composite negative electrode material particle in Comparative Example 2. FIG. It can be seen from FIG. 4 that the thickness of the carbon cladding layer is thicker than that of Examples 1 and 2. FIG. 5 is an electron microscope photograph of the cross section of the silicon composite negative electrode material particle in Comparative Example 3. FIG. It can be seen from FIG. 5 that the thickness of the carbon cladding layer is thinner than that of Examples 1 and 2. FIG. 6 is an electron microscope photograph of the cross section of the silicon composite negative electrode material particle in Comparative Example 4. FIG. It can be seen from FIG. 6 that the thickness of the carbon cladding layer is thicker than that of Examples 1 and 2. At the same time, the inner core presents a number of small particle-like forms. It can be seen that when the M content in the distributed composite is higher than 30%, the excess M will rapidly react with SiO and release a large amount of heat, resulting in the generation of Si The crystal grains are very large, so it shows the appearance of uneven distribution of the inner core.
二、电化学性能测试(一)：2. Electrochemical performance test (1):
II、锂离子二次电池200的制备：采用各实施例和对比例制得的硅复合物负极材料与导电剂Super-P、导电剂SFG-6、粘结剂LA133按照75:5:10:10的质量比混合后调成浆料，涂覆在铜箔负极集流体242上，控制浆料的总固体含量为50％，并经真空干燥、辊压，形成负极活性材料层244，并制备成负极240极片；正极220采用锂片，使用1mol/L LiPF6的三组分混合溶剂EC:DMC:EMC＝1:1:1(体积比)，v/v溶液为电解液260，聚丙烯微孔膜为隔膜280，组装成CR2016模拟电池。II, the preparation of lithium ion secondary battery 200: adopt the silicon composite negative electrode material and conductive agent Super-P, conductive agent SFG-6, binder LA133 that each embodiment and comparative example make according to 75:5:10: After mixing with a mass ratio of 10, it was mixed into a slurry, which was coated on the copper foil negative electrode current collector 242, the total solid content of the slurry was controlled to be 50%, and the negative electrode active material layer 244 was formed by vacuum drying and rolling, and prepared A negative electrode 240 pole piece is formed; the positive electrode 220 is a lithium piece, a three-component mixed solvent of 1mol/L LiPF6 EC:DMC:EMC=1:1:1 (volume ratio), the v/v solution is electrolyte 260, polypropylene The microporous membrane is the separator 280, which is assembled into a CR2016 simulated battery.
III、电化学性能测试：III. Electrochemical performance test:
首次脱锂比容量测试(mAh/g)(即Q 1(dis))： The first delithiation specific capacity test (mAh/g) (ie Q 1(dis) ):
Q 1(cha)＝C l(cha)/m(公式1) Q 1(cha) =C l(cha) /m (Formula 1)
Q 1(dis)：以0.1C倍率电流充放电时首次放电比容量，(mAh/g)； Q 1(dis) : first discharge specific capacity when charging and discharging at 0.1C rate current, (mAh/g);
C 1(dis)：以0.1C倍率电流充放电时首次放电容量，(mAh)； C 1(dis) : the first discharge capacity when charging and discharging at 0.1C rate current, (mAh);
m：活性物质质量，(g)；m: mass of active substance, (g);
首次嵌锂比容量测试(mAh/g)(即Q l(cha))： The first lithium insertion specific capacity test (mAh/g) (ie Q l(cha) ):
Q 1(cha)＝C l(cha)/m(公式2) Q 1(cha) =C l(cha) /m (Formula 2)
Q 1(cha)：以0.1C倍率电流充放电时首次充电比容量，(mAh/g)； Q 1(cha) : first charge specific capacity when charging and discharging at 0.1C rate current, (mAh/g);
C 1(cha)：以0.1C倍率电流充放电时首次充电容量，(mAh)； C 1(cha) : initial charge capacity when charging and discharging at 0.1C rate current, (mAh);
首次库伦效率测试(％)(即E 1)： First Coulombic Efficiency Test (%) (ie E 1 ):
E 1＝Q l(dis)/Q l(cha)×100％(公式3) E 1 =Q l(dis) /Q l(cha) ×100% (Formula 3)
(参照《硅炭》GB/T 38823-2020的公式D.3)；(Refer to Formula D.3 of "Silicon Carbon" GB/T 38823-2020);
以上电化学性能采用武汉金诺电子有限公司LAND电池测试***，在常温条件，0.1C恒流充放电，充放电电压限制在0.005～1.5V。测试实施例1-6、对比例1-6的材料制作的实验扣式电池的首次库伦效率，在室温条件测试，测试结果如表1所示。The above electrochemical performance is based on the LAND battery test system of Wuhan Jinnuo Electronics Co., Ltd., under normal temperature conditions, 0.1C constant current charge and discharge, and the charge and discharge voltage is limited to 0.005 ~ 1.5V. The first coulombic efficiencies of the experimental button cells made from the materials of Examples 1-6 and Comparative Examples 1-6 were tested at room temperature. The test results are shown in Table 1.
表1Table 1
   嵌锂容量(mAh/g)Lithium intercalation capacity (mAh/g) 脱锂容量(mAh/g)Delithiation capacity (mAh/g) 首周库伦效率(％)Coulombic efficiency in the first week (%)
实施例1Example 1 15461546 13961396 90.390.3
实施例2Example 2 15221522 13581358 89.289.2
实施例3Example 3 16771677 14271427 85.185.1
实施例4Example 4 17201720 14401440 83.783.7
实施例5Example 5 17171717 14531453 84.684.6
实施例6Example 6 15181518 13531353 89.189.1
实施例7Example 7 15381538 13861386 90.190.1
对比例1Comparative Example 1 16241624 13191319 81.281.2
对比例2Comparative Example 2 14371437 12701270 88.488.4
对比例3Comparative Example 3 15911591 12841284 80.780.7
对比例4Comparative Example 4 15921592 13561356 85.285.2
对比例5Comparative Example 5 21212121 16501650 77.877.8
对比例6Comparative Example 6 10741074 989989 92.192.1
二、电化学性能测试(二)：2. Electrochemical performance test (2):
I、锂离子二次电池200的制备：1, the preparation of lithium ion secondary battery 200:
采用各实施例和对比例制得的硅复合物负极材料与石墨按10:90的比例混合，再与羧甲基纤维素钠CMC(作为粘结剂)、粘结剂丁苯橡胶SBR(作为粘结剂)、导电剂Super-P、导电剂KS-6按照92:2:2:2的质量比混合后调成浆料，涂覆在铜箔负极集流体242上，控制浆料的总固体含量为50％，并经真空干燥、辊压，形成负极活性材料层244，并制备成负极240极片；正极220采用锂片，使用1mol/L LiPF6的三组分混合溶剂EC:DMC:EMC＝1:1:1(体积比)，v/v溶液为电解液260，聚丙烯微孔膜为隔膜280以及外壳290，同时利用外壳290组装成CR2016模拟电池。The silicon composite negative electrode material prepared by each example and the comparative example is mixed with graphite in a ratio of 10:90, and then mixed with sodium carboxymethyl cellulose CMC (as a binder) and a binder styrene-butadiene rubber SBR (as a binder). Binder), conductive agent Super-P, and conductive agent KS-6 are mixed in a mass ratio of 92:2:2:2 to form a slurry, which is coated on the copper foil negative current collector 242 to control the total amount of the slurry. The solid content is 50%, and through vacuum drying and rolling, the negative electrode active material layer 244 is formed, and the negative electrode 240 pole piece is prepared; the positive electrode 220 adopts a lithium piece, and uses 1mol/L LiPF The three-component mixed solvent EC:DMC: EMC=1:1:1 (volume ratio), the v/v solution is the electrolyte 260, the polypropylene microporous membrane is the separator 280 and the shell 290, and the shell 290 is used to assemble a CR2016 simulated battery.
II、电化学性能测试：II. Electrochemical performance test:
首周放电比容量(mAh/g)＝首周放电容量/m；The first week discharge specific capacity (mAh/g) = the first week discharge capacity/m;
第50周放电比容量(mAh/g)＝第50周放电容量/m(公式4)；The 50th cycle discharge specific capacity (mAh/g) = the 50th cycle discharge capacity/m (formula 4);
50周循环保持率(％)＝第50周放电比容量/首周放电比容量×100％(公式5)；50-cycle cycle retention rate (%) = discharge specific capacity in the 50th cycle / discharge specific capacity in the first cycle × 100% (Formula 5);
循环性能测试使用30mA的电流进行恒流充放电实验，充放电电压限制在0～1.5V。采用武汉金诺电子有限公司LAND电池测试***测试实施例1的材料制作的实验扣式电池的50周循环保持率，充放电制度参见表2，在室温条件测试，测试结果如表3所示。The cycle performance test uses a current of 30mA for constant current charge-discharge experiments, and the charge-discharge voltage is limited to 0-1.5V. The 50-cycle cycle retention rate of the experimental button battery made of the material of Example 1 was tested by using the LAND battery test system of Wuhan Jinnuo Electronics Co., Ltd.
表2Table 2
Figure PCTCN2021091857-appb-000001
Figure PCTCN2021091857-appb-000001
表3table 3
   首周容量(mAh/g)First week capacity (mAh/g) 50周容量(mAh/g)50-week capacity (mAh/g) 50周循环保持率(％)50-week cycle retention rate (%)
实施例1Example 1 481481 435435 90.590.5
实施例2Example 2 476476 429429 90.290.2
实施例3Example 3 478478 432432 90.390.3
实施例4Example 4 491491 446446 90.890.8
实施例5Example 5 486486 436436 89.889.8
实施例6Example 6 473473 425425 89.989.9
对比例1Comparative Example 1 483483 387387 80.180.1
对比例2Comparative Example 2 479479 389389 81.281.2
对比例3Comparative Example 3 490490 423423 86.386.3
对比例4Comparative Example 4 492492 432432 87.887.8
对比例5Comparative Example 5 501501 441441 88.188.1
对比例6Comparative Example 6 453453 368368 81.381.3
由以上对比数据可以看出，根据本公开所述方法制备的硅复合物在循环性能方面具有明显的优势，原因是：本公开的实施例将复合物负极材料的碳层厚度限制在50nm-200nm之间，碳层厚度在此范围内的复合物负极材料，其复合物颗粒的表面能够被完全覆盖，且厚度也被控制在了最适宜的范围内，能够有效的缓冲充放电过程中复合物的体积膨胀。应用在电池中时既不会出现因部分位置裸露而出现的电解液260过度消耗及容量减少的问题，也不会出现因碳层过厚而出现的循环过程中碳层开裂的问题，且适宜厚度的碳层对材料的体积控制也产生了积极作用，所以能够显著的提升复合物的容量效率及循环性能。It can be seen from the above comparative data that the silicon composite prepared according to the method of the present disclosure has obvious advantages in terms of cycle performance, the reason is: the embodiment of the present disclosure limits the carbon layer thickness of the composite negative electrode material to 50nm-200nm In between, the composite negative electrode material with carbon layer thickness within this range, the surface of the composite particles can be completely covered, and the thickness is also controlled within the most suitable range, which can effectively buffer the composite during the charging and discharging process. volume expansion. When applied in the battery, there will be neither the problem of excessive consumption of electrolyte 260 and the reduction of capacity due to exposed parts, nor the problem of cracking of the carbon layer during the cycle due to the excessive thickness of the carbon layer, and it is suitable for The thickness of the carbon layer also has a positive effect on the volume control of the material, so the capacity efficiency and cycle performance of the composite can be significantly improved.
通过实施例1与对比例1、3对比可知，当硅复合物表面包覆厚度小于50nm时，因对比例中制备的硅复合物颗粒的表面不能完全被碳层覆盖，仍存在较多的裸露部位，这样的材料应用在电池中，一方面裸露部位会与电解液260直接接触，反复生成不稳定的SEI膜，导致电解液260被过度消耗，造成循环性能下降，从表1和3中可以看出，对比例1和3中的首周库伦效率以及50周循环保持率均下降明显；另一方面，裸露的部位导电性极差，该部位的活性材料不能有效地进行嵌脱锂反应，会造成容量的减少。It can be seen from the comparison between Example 1 and Comparative Examples 1 and 3 that when the coating thickness of the silicon composite surface is less than 50 nm, because the surface of the silicon composite particles prepared in the comparative example cannot be completely covered by the carbon layer, there are still many exposed If such a material is used in a battery, on the one hand, the exposed part will be in direct contact with the electrolyte 260, and an unstable SEI film will be formed repeatedly, resulting in excessive consumption of the electrolyte 260, resulting in decreased cycle performance. From Tables 1 and 3, it can be seen that It can be seen that the Coulombic efficiency in the first week and the 50-week cycle retention rate in Comparative Examples 1 and 3 both decreased significantly; on the other hand, the exposed part has extremely poor conductivity, and the active material in this part cannot effectively perform lithium intercalation and delithiation reactions. will result in a reduction in capacity.
通过实施例1与对比例2、4对比可知，当硅复合物表面包覆厚度大于200nm时，硅复合物颗粒表面的碳层过厚，这样的材料应用在电池中时，在反复的充放电过程中偏厚的碳层易受到颗粒内部应力的作用而开裂，造成硅复合物与电解液260直接接触以及裸露位置因失去电接触而失活，从而导致材料性能的降低。通过比较实施例与对比例2、4的首周库伦效率以及50周循环保持率(想见表1、3)，可以明显看出对比例的循环性能下降明显，而本实施例中的电极循环性能提高明显；同时其嵌锂容量、脱锂容量明显降低。By comparing Example 1 with Comparative Examples 2 and 4, it can be seen that when the coating thickness on the surface of the silicon composite is greater than 200 nm, the carbon layer on the surface of the silicon composite particle is too thick. During the process, the thick carbon layer is easily cracked by the internal stress of the particles, resulting in the direct contact between the silicon composite and the electrolyte 260 and the deactivation of the exposed position due to loss of electrical contact, resulting in a decrease in material performance. By comparing the first week Coulombic efficiency and the 50-cycle cycle retention rate (see Tables 1 and 3) of the example and the comparative examples 2 and 4, it can be clearly seen that the cycle performance of the comparative example has decreased significantly, while the electrode cycle performance of this example The improvement is obvious; at the same time, the lithium intercalation capacity and the delithiation capacity are obviously reduced.
通过实施例1与对比例5-6对比可知，当复合物中的M含量低于1％时，能够与SiO发生反应的M的量很少，生成的有利于提升材料首周库伦效率的Si的量和作为充放电过程中的缓冲物质的M的硅酸盐也相应的少，所以以之制备的硅基负极材料100的首周库伦效率和循环性能均无明显提升；当复合物中的M含量高于30％时，过量的M会与SiO快速反应并放出大量的热量，导致生成的Si的晶粒极大，以之制备硅基负极材料100，虽然首周库伦效率较高，但一方面过多量的M的引入降低了材料的容量，另一方面具有极大的晶粒的Si在充放电过程中会产生巨大的膨胀，导致材料的循环性能极差，无实际意义。It can be seen from the comparison between Example 1 and Comparative Examples 5-6 that when the content of M in the composite is less than 1%, the amount of M that can react with SiO is very small, and Si is generated which is beneficial to improve the Coulombic efficiency of the material in the first week. The amount of silicon-based anode material 100 and the silicate of M as a buffer substance in the charging and discharging process are also correspondingly small, so the first week Coulombic efficiency and cycle performance of the silicon-based negative electrode material 100 prepared with it are not significantly improved; When the M content is higher than 30%, the excess M will rapidly react with SiO and release a large amount of heat, resulting in extremely large Si grains, so as to prepare the silicon-based anode material 100. Although the coulombic efficiency in the first week is high, the On the one hand, the introduction of too much M reduces the capacity of the material, and on the other hand, Si with extremely large grains will expand greatly during the charging and discharging process, resulting in extremely poor cycle performance of the material, which is of no practical significance.
申请人声明，本公开通过上述实施例来说明本公开的详细工艺设备和工艺流程，但本公开并不局限于上述详细工艺设备和工艺流程，即不意味着本公开必须依赖上述详细工艺设备和工艺流程才能实施。所属技术领域的技术人员应该明了，对本公开的任何改进，对本公开产品各原料的等效替换及辅助成分的添加、具体方式的选择等，均落在本公开的保护范围和公开范围之内。The applicant declares that the present disclosure illustrates the detailed process equipment and process flow of the present disclosure through the above-mentioned embodiments, but the present disclosure is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present disclosure must rely on the above-mentioned detailed process equipment and process flow. Process flow can be implemented. Those skilled in the art should understand that any improvement to the present disclosure, the equivalent replacement of each raw material of the disclosed product, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present disclosure.
申请人声明，本公开通过上述实施例来说明本公开的详细方法，但本公开并不局限于上述详细方法，即不意味着本公开必须依赖上述详细方法才能实施。所属技术领域的技术人员应该明了，对本公开的任何改进，对本公开产品各原料的等效替换及辅助成分的添加、具体方式的选择等，均落在本公开的保护范围和公开范围之内。The applicant declares that the present disclosure illustrates the detailed method of the present disclosure through the above-mentioned embodiments, but the present disclosure is not limited to the above-mentioned detailed method, that is, it does not mean that the present disclosure must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that any improvement to the present disclosure, the equivalent replacement of each raw material of the disclosed product, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present disclosure.
工业实用性Industrial Applicability
综上所述，本公开提供了一种硅基负极材料、负极和锂离子电池及其制备方法。该硅基负极材料具有以提高硅复合物的导电性，并且能够显著提升硅复合物的容量效率和循环性能，同时制备的负极和锂离子电池具有高容量效率和循环性能等特性。In summary, the present disclosure provides a silicon-based negative electrode material, a negative electrode, a lithium ion battery, and a preparation method thereof. The silicon-based negative electrode material can improve the conductivity of the silicon composite, and can significantly improve the capacity efficiency and cycle performance of the silicon composite, and the prepared negative electrode and lithium ion battery have the characteristics of high capacity efficiency and cycle performance.

Claims (14)

  1. 一种硅基负极材料(100)，所述硅基负极材料(100)包括：A silicon-based negative electrode material (100), the silicon-based negative electrode material (100) comprising:
    内核(120)，所述内核(120)包括硅、硅氧化物及M的硅酸盐；所述硅氧化物的化学式为SiO x，0＜x＜2，所述M为金属；及 Core (120), said core (120) including silicates, silicon, silicon oxide and M; and the chemical formula of the silicon oxide is SiO x, 0 <x <2 , M is a metal; and
    碳被膜(140)，所述碳被膜(140)形成于所述内核(120)的表面，所述碳被膜(140)的厚度为50nm-200nm。A carbon coating (140), the carbon coating (140) is formed on the surface of the inner core (120), and the thickness of the carbon coating (140) is 50nm-200nm.
  2. 根据权利要求1所述的硅基负极材料(100)，其中，所述碳被膜(140)的厚度为100nm-200nm。The silicon-based negative electrode material (100) according to claim 1, wherein the carbon coating (140) has a thickness of 100nm-200nm.
  3. 根据权利要求1所述的硅基负极材料(100)，其中，所述M包括Li、Mg、Al、Zn、Ca、Na和Ti中的至少一种。The silicon-based negative electrode material (100) according to claim 1, wherein the M comprises at least one of Li, Mg, Al, Zn, Ca, Na and Ti.
  4. 根据权利要求1所述的硅基负极材料(100)，其中，所述M包括Fe或者所述Fe与Li、Mg、Al、Zn、Ca、Na和Ti中的任意一种或至少两种的组合。The silicon-based negative electrode material (100) according to claim 1, wherein the M comprises Fe or any one or at least two of the Fe and Li, Mg, Al, Zn, Ca, Na and Ti. combination.
  5. 根据权利要求1-4任一项所述的硅基负极材料(100)，其中，以所述硅基负极材料(100)的总质量为100％计，所述M的质量分数为1％-30％。The silicon-based negative electrode material (100) according to any one of claims 1-4, wherein, based on the total mass of the silicon-based negative electrode material (100) being 100%, the mass fraction of M is 1%- 30%.
  6. 根据权利要求1-5任一项所述的硅基负极材料(100)，其中，所述硅基负极材料(100)的D50为0.5μm-40μm；及/或The silicon-based negative electrode material (100) according to any one of claims 1-5, wherein the D50 of the silicon-based negative electrode material (100) is 0.5 μm-40 μm; and/or
    所述硅基负极材料(100)的比表面积为0.5m 2/g-40m 2/g。 The specific surface area of the silicon-based negative electrode material (100) is 0.5m 2 /g-40m 2 /g.
  7. 根据权利要求1-6任一项所述的硅基负极材料(100)的制备方法，所述方法包括以下步骤：The preparation method of a silicon-based negative electrode material (100) according to any one of claims 1-6, the method comprising the steps of:
    将SiO y蒸汽和M单质蒸汽混合，进行冷却凝结处理，得到硅复合物，其中，0＜y＜2； Mixing SiO y steam and M elemental steam, and performing cooling and condensation treatment to obtain a silicon composite, wherein 0<y<2;
    对所述硅复合物进行碳包覆处理，以在所述硅复合物表面形成厚度为50nm-200nm的碳被膜(140)，得到硅基负极材料(100)。The silicon composite is subjected to carbon coating treatment to form a carbon film (140) with a thickness of 50 nm to 200 nm on the surface of the silicon composite to obtain a silicon-based negative electrode material (100).
  8. 根据权利要求7所述的方法，其中，将SiO蒸汽和M单质蒸汽混合，进行冷却凝结处理，得到硅复合物；The method according to claim 7, wherein, the SiO steam and the M elemental steam are mixed, and subjected to cooling and condensation treatment to obtain the silicon composite;
    对所述硅复合物进行碳包覆处理，以在所述硅复合物表面形成厚度为50nm-200nm的碳被膜(140)，得到硅基负极材料(100)。The silicon composite is subjected to carbon coating treatment to form a carbon film (140) with a thickness of 50 nm to 200 nm on the surface of the silicon composite to obtain a silicon-based negative electrode material (100).
  9. 根据权利要求8所述的方法，其中，The method of claim 8, wherein,
    所述SiO蒸汽和M单质蒸汽的制备方法包括以下步骤：调控含有SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料的反应环境的温度和压力，得到所述SiO蒸汽和所述M单质蒸汽。The preparation method of the SiO steam and the M elemental vapor comprises the following steps: regulating and controlling the temperature and pressure of the reaction environment containing SiO and/or the raw material for preparing SiO and the M elemental substance and/or the raw material for preparing the M elemental substance, to obtain the SiO steam and the raw material for preparing the M elemental substance. The M elemental steam.
  10. 根据权利要求9所述的方法，其中，The method of claim 9, wherein,
    所述制备SiO的原料包括将Si与SiO 2以质量比为1:1.5-1:2.5混合后的混合物；及/或 The raw materials for preparing SiO include a mixture of Si and SiO 2 in a mass ratio of 1:1.5-1:2.5; and/or
    所述制备M单质的原料包括用于制备M单质的物质混合后的混合物；及/或The raw material for preparing the elemental M includes a mixture of the substances used for preparing the elemental M; and/or
    所述反应环境为真空环境；及/或The reaction environment is a vacuum environment; and/or
    形成所述含有SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料的反应环境具体操作为：将所述SiO和/或制备SiO的原料置于真空炉中；及/或The specific operation of the reaction environment for forming the SiO-containing and/or SiO-preparing raw materials and M elemental substances and/or M elemental-preparing raw materials is: placing the SiO and/or SiO-preparing raw materials in a vacuum furnace; and/or
    将SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料置于反应器中的步骤包括：将所述SiO和/或制备SiO的原料置于真空炉靠近炉尾的一端，将所述M单质和/或制备M单质的原料置于真空炉靠近炉口的一端；The step of placing the SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor comprises: placing the SiO and/or the raw material for preparing SiO at one end of the vacuum furnace close to the furnace tail, The M element and/or the raw material for preparing M element is placed at one end of the vacuum furnace close to the furnace mouth;
    或者，将SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料置于反应器中的步骤包括：将所述SiO和/或制备SiO的原料置于真空炉靠近炉口的一端，将所述M单质和/或制备M单质的原料置于真空炉靠近炉尾的一端；Alternatively, the step of placing the SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO in a vacuum furnace close to the furnace mouth At one end, the M element and/or the raw material for preparing M element is placed at one end of the vacuum furnace close to the furnace tail;
    或者，将SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料置于反应器中的步骤包括：将所述SiO和/或制备SiO的原料与所述M单质和/或制备M单质的原料混合 后置于真空炉内；及/或Alternatively, the step of placing SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M in the reactor includes: placing the SiO and/or the raw material for preparing SiO with the M element and/or The raw materials for the preparation of elemental M are mixed and placed in a vacuum furnace; and/or
    调控含有SiO和/或制备SiO的原料以及M单质和/或制备M单质的原料的反应环境的温度和压力步骤中的所述温度为1200℃-1600℃，所述压力为0.1Pa-500Pa。The temperature and pressure in the step of regulating the temperature and pressure of the reaction environment containing SiO and/or the raw material for preparing SiO and the M element and/or the raw material for preparing M are 1200°C-1600°C, and the pressure is 0.1Pa-500Pa.
  11. 根据权利要求7-10任一所述的方法，其中，所述方法还包括在得到硅复合物步骤之后，对所述硅复合物进行碳包覆处理步骤之前进行下述步骤：对所述硅复合物粉碎、分级和烧成中的至少一种；及/或The method according to any one of claims 7-10, wherein the method further comprises performing the following step after the step of obtaining the silicon composite and before the carbon coating treatment step on the silicon composite: at least one of crushing, classifying and sintering the composite; and/or
    所述方法还包括在得到硅复合物凝结成固相材料步骤之后，对所述硅复合物固相材料进行碳包覆处理步骤之前进行下述步骤：所述步骤按方案Ⅰ、方案Ⅱ或方案Ⅲ中的任意一种进行；The method further includes performing the following steps after the step of obtaining the silicon composite and condensing it into a solid phase material, and before the carbon coating treatment step on the silicon composite solid phase material: the step is according to scheme I, scheme II or scheme. any one of III;
    其中，所述方案Ⅰ为：对所述硅复合物依次进行粉碎、分级、烧成处理；Wherein, the scheme I is: pulverizing, classifying and firing the silicon composite in sequence;
    所述方案Ⅱ为：对所述硅复合物依次进行粉碎、烧成、分级处理；The scheme II is: pulverizing, sintering and classifying the silicon composite in sequence;
    所述方案Ⅲ为：对所述硅复合物依次进行烧成、粉碎、分级处理；及/或The scheme III is: sintering, pulverizing and classifying the silicon composite in sequence; and/or
    对所述硅复合物进行碳包覆处理的步骤中的所述碳包覆的方式包括：气相包覆、液相包覆和固相包覆中的至少一种；及/或The method of carbon coating in the step of carbon coating treatment on the silicon composite includes: at least one of gas phase coating, liquid phase coating and solid phase coating; and/or
    对所述硅复合物进行碳包覆处理的步骤中的碳包覆采用气相包覆的方式进行，通过控制含碳气体的流量及通入时间控制碳被膜(140)的厚度，获得硅基负极材料(100)；及/或The carbon coating in the step of carbon coating treatment on the silicon composite is carried out by gas-phase coating, and the thickness of the carbon coating (140) is controlled by controlling the flow rate and the passage time of the carbon-containing gas to obtain a silicon-based negative electrode Materials (100); and/or
    对所述硅复合物进行碳包覆处理的步骤中的碳包覆采用固相包覆或液相包覆的方式进行，通过控制混入含碳物质的质量及烧成温度控制碳被膜(140)的厚度，获得硅基负极材料(100)。The carbon coating in the step of carbon coating treatment on the silicon composite is carried out by means of solid-phase coating or liquid-phase coating, and the carbon coating is controlled by controlling the quality of the mixed carbon-containing material and the firing temperature (140) thickness to obtain a silicon-based negative electrode material (100).
  12. 根据权利要求8-11任一项所述的方法，其中，所述方法包括以下步骤：The method according to any one of claims 8-11, wherein the method comprises the steps of:
    将SiO或制备SiO的原料及M单质或制备M单质的原料放入真空炉中；Put SiO or the raw material for preparing SiO and M elemental substance or the raw material for preparing M elemental substance into the vacuum furnace;
    在1200-1600℃、0.5-500Pa的条件下生成M蒸汽与SiO蒸汽；M steam and SiO steam are generated under the conditions of 1200-1600℃ and 0.5-500Pa;
    将所述M蒸汽与SiO蒸汽在置于真空炉内的混合装置中混合均匀，然后进行冷却凝结，得到固相的M与SiO混合的硅复合物；The M steam and the SiO steam are uniformly mixed in a mixing device placed in a vacuum furnace, and then cooled and condensed to obtain a solid-phase M and SiO mixed silicon composite;
    对所述硅复合物进行粉碎和分级，制备成粉体材料；pulverizing and classifying the silicon composite to prepare a powder material;
    将所述粉体材料进行碳包覆，使硅复合物表面的碳被膜(140)厚度为50nm-200nm之间，得到硅基负极材料(100)。The powder material is coated with carbon, so that the thickness of the carbon film (140) on the surface of the silicon composite is between 50 nm and 200 nm to obtain a silicon-based negative electrode material (100).
  13. 一种负极(240)，所述负极(240)包括：如权利要求1-6任一所述的硅基负极材料(100)。A negative electrode (240), the negative electrode (240) comprising: the silicon-based negative electrode material (100) according to any one of claims 1-6.
  14. 一种锂离子二次电池(200)，所述锂离子二次电池(200)包含权利要求1-6任一项所述的硅基负极材料(100)。A lithium ion secondary battery (200), the lithium ion secondary battery (200) comprising the silicon-based negative electrode material (100) according to any one of claims 1-6.
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