WO2024020880A1 - 硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池、用电装置和碳基体 - Google Patents

硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池、用电装置和碳基体 Download PDF

Info

Publication number
WO2024020880A1
WO2024020880A1 PCT/CN2022/108327 CN2022108327W WO2024020880A1 WO 2024020880 A1 WO2024020880 A1 WO 2024020880A1 CN 2022108327 W CN2022108327 W CN 2022108327W WO 2024020880 A1 WO2024020880 A1 WO 2024020880A1
Authority
WO
WIPO (PCT)
Prior art keywords
silicon
carbon composite
composite material
carbon
region
Prior art date
Application number
PCT/CN2022/108327
Other languages
English (en)
French (fr)
Inventor
李圆
董晓斌
吕子建
刘良彬
王家政
Original Assignee
宁德时代新能源科技股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to PCT/CN2022/108327 priority Critical patent/WO2024020880A1/zh
Publication of WO2024020880A1 publication Critical patent/WO2024020880A1/zh

Links

Images

Classifications

    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of battery technology, specifically, to a silicon-carbon composite material and its preparation method, negative electrode material, negative electrode plate, electrode assembly, battery, electrical device and carbon matrix.
  • Silicon anode material has the advantages of high energy density, low lithium insertion potential and wide source, and is expected to become the next generation anode material. However, the silicon anode material undergoes severe volume expansion during actual charging and discharging. After a certain number of cycles, the electrode piece will be pulverized and peeled off, causing the battery performance to plummet.
  • this application provides a silicon-carbon composite material and a preparation method thereof, negative electrode material, negative electrode plate, electrode assembly, battery, electrical device and carbon matrix, which can reduce the influence of silicon expansion stress on the silicon-carbon composite material.
  • the present application provides a silicon-carbon composite material, including: a carbon matrix and a silicon material.
  • the carbon matrix has a cross-linked pore structure inside, and the silicon material is at least partially distributed in the cross-linked pore structure.
  • the flexibility C1 value of the silicon-carbon composite material satisfies 0.4 ⁇ C1 ⁇ 2. The flexibility is measured by the following method: apply a pressure of 2t to the silicon-carbon composite material, hold the pressure for 10 seconds, and release the pressure for 100 seconds.
  • the silicon material is at least partially distributed in the carbon matrix with a cross-linked pore structure.
  • C1 in the present application is the multiple of the rebound deformation amount to the compression deformation amount of the silicon-carbon composite material, used to represent silicon Flexibility of carbon composites.
  • the silicon-carbon composite material has good flexibility. On the one hand, it can reduce the influence of silicon expansion stress on the overall silicon-carbon composite material.
  • the carbon matrix frame has a certain degree of shrinkage. It can further accommodate and release residual stress, thereby maintaining the overall stability of the silicon-carbon composite material.
  • the silicon-carbon composite material has good flexibility. On the one hand, it can reduce the influence of silicon expansion stress on the overall silicon-carbon composite material. On the other hand, the carbon matrix frame has a certain degree of shrinkage. It can further accommodate and release residual stress, thereby maintaining the overall stability of the silicon-carbon composite material.
  • M1 in this application is the change in compacted density of the silicon-carbon composite material after the first and 20th pressure relief. It is used to indicate the deformation degree of the silicon-carbon composite material after multiple pressure reliefs, and when 0.05 ⁇ M1 ⁇ 0.18 , silicon-carbon composite materials have better compression resistance.
  • N1 is the change in compaction density of the silicon-carbon composite material when the pressure is applied for the first and 20th times. It is used to indicate the degree of deformation of the silicon-carbon composite material under multiple pressures. When 0.04 ⁇ N1 ⁇ 0.2, it is beneficial to make The C1 value satisfies 0.8 ⁇ C1 ⁇ 2, which makes the silicon carbon composite material have better flexibility.
  • the carbon matrix sequentially includes a first region and a second region in a direction extending from the center to the surface, and the carbon matrix is composed of the first region and the second region, and the volume of the second region is the volume of the first region. 2 times, the ratio of the number of pores with a pore diameter of 2 nm to 1000 nm in the first region to the number of pores with a pore diameter of 2 nm to 1000 nm in the second region is >1.
  • the ratio of the number of pores with a pore diameter of 2 nm to 500 nm in the first region and the number of pores with a pore diameter of 2 nm to 500 nm in the second region is >1.
  • the ratio of the number of pores with a pore diameter of 2 nm to 200 nm in the first region and the number of pores with a pore diameter of 2 nm to 200 nm in the second region is >1.
  • the specific surface area SSA value of the silicon-carbon composite material satisfies 1g/cm2 ⁇ SSA ⁇ 10g/cm2.
  • the specific surface area SSA value of the silicon-carbon composite material satisfies 3g/cm2 ⁇ SSA ⁇ 7g/cm2.
  • the silicon-carbon composite material has fewer surface defects, which is beneficial to forming a stable SEI film and reducing irreversible lithium ion loss.
  • the silicon carbon composite material has Dv10 ⁇ 5 ⁇ m, Dv50 ⁇ 8 ⁇ m, Dv90 ⁇ 20 ⁇ m, and (Dv90-Dv10)/Dv50 ⁇ 1.6. It is beneficial to increase the compaction density of silicon-carbon composite materials when used, improve the electrical contact of active particles, thereby improving the conductivity of the negative electrode piece.
  • the silicon-carbon composite material has a powder compaction density PD ⁇ 1.1 g/cm3 at 5t.
  • the silicon-carbon composite material has a porous structure and has a powder compaction density PD ⁇ 1.1 g/cm3 at 5t.
  • the silicon material includes any one or more of silicon oxide compounds, silicon elements, and alloy silicon.
  • Silicon material has the advantages of high energy density, low lithium insertion potential and wide source. Silicon oxide compounds, silicon elemental and alloy silicon can be loaded in the pores of the carbon matrix to produce silicon-carbon composite materials, which are used to make negative electrode materials and energy density. High battery.
  • the present application provides a method for preparing the silicon-carbon composite material of the above embodiment, which includes: subjecting the raw materials to a first heat treatment to obtain a solid resin, and subjecting the pulverized solid resin to a second heat treatment to dissolve the neutral solvent. Volatilize to obtain a carbon precursor, which is subjected to pyrolysis and carbonization to obtain a carbon matrix, and the silicon material is compounded in the cross-linked pore structure of the carbon matrix.
  • Raw materials include resin, porogen and neutral solvent.
  • the raw materials including resin, porogen and neutral solvent can be formed into a solid resin through the first heat treatment, which is beneficial to subsequent processing.
  • the pulverized solid resin is then subjected to a second heat treatment to volatilize the solvent so that the pores are interconnected to form a cross-linked pore structure, thereby obtaining a carbon precursor.
  • the carbon precursor is subjected to pyrolysis carbonization treatment to carbonize organic matter to obtain a carbon matrix.
  • the preparation method of the silicon-carbon composite material of the present application uses an in-situ porogenic method.
  • the obtained carbon matrix has a cross-linked pore structure evenly distributed inside and on the surface, and the pore diameter is suitable, which is conducive to filling the pores of the carbon matrix with silicon material. and dispersion, thereby producing silicon-carbon composite materials with a more stable structure.
  • the treatment temperature of the second heat treatment is 150-400°C, and the treatment time is at least 10 hours. Choosing an appropriate treatment temperature and treatment time for the second heat treatment is conducive to volatilizing the solvent and connecting the pores to form a cross-linked pore structure. If the temperature is too high, the pores of the silicon-carbon composite material will become larger, and the silicon-carbon composite material will become larger. The material becomes brittle and the C1 value of the silicon-carbon composite material becomes smaller.
  • the mass ratio of the resin to the neutral solvent is 1:10 to 10:1, and the mass ratio of the resin to the porogen is 1:5 to 10:1.
  • the resin includes any one or more of phenolic resin, epoxy resin and polyurethane.
  • the neutral solvent includes any one or more of methanol, ethanol, ethylene glycol, polyethylene glycol, glycerin and isopropyl alcohol.
  • porogens include potassium chloride, sodium chloride, zinc chloride, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, phosphoric acid, sodium acetate, zinc acetate, nickel acetate, and acetic acid Any one or more types of ammonium. Choosing an appropriate ratio of resin and neutral solvent is beneficial to controlling the number and size of pores in the silicon-carbon composite material.
  • the first heat treatment includes standing at 60-150°C for at least 10 hours. Selecting an appropriate treatment temperature and treatment time for the first heat treatment is beneficial to obtaining a solid resin.
  • the pyrolytic carbonization treatment includes sintering at 600 to 1600°C for 1 to 3 hours.
  • the temperature of the pyrolysis carbonization treatment is 800 to 1000°C. Choosing the appropriate treatment temperature and time for pyrolysis carbonization is beneficial to obtaining a carbon matrix with a cross-linked pore structure evenly distributed inside and on the surface.
  • the present application provides a negative electrode material, which includes the silicon carbon composite material of the above embodiment or the silicon carbon composite material prepared according to the preparation method of the silicon carbon composite material of the above embodiment.
  • the present application provides a negative electrode sheet, which includes the negative electrode material of the above embodiment.
  • the present application provides an electrode assembly, which includes the negative electrode piece of the above embodiment.
  • the present application provides a battery cell, which includes the electrode assembly of the above embodiment.
  • the present application provides a battery, which includes the battery cell of the above embodiment.
  • the present application provides an electrical device, which includes the battery of the above embodiment, and the battery is used to provide electrical energy.
  • the present application provides a carbon matrix, which has a cross-linked pore structure inside.
  • the flexibility C2 value of the carbon matrix satisfies 0.8 ⁇ C2 ⁇ 2.
  • C2 in the present application is the multiple of the rebound deformation amount of the carbon matrix to the compression deformation amount, and is used to represent the flexibility of the carbon matrix.
  • the C2 value satisfies 0.8 ⁇ C2 ⁇ 2, the carbon matrix has good flexibility.
  • M2 is defined as P6-P5
  • N2 is defined as P8-P7, 0.04 ⁇ M2 ⁇ 0.18, 0.04 ⁇ N2 ⁇ 0.08.
  • M2 in this application is the change in compacted density of the carbon matrix after the first and 20th pressure relief. It is used to indicate the degree of deformation of the silicon-carbon composite material after multiple pressure reliefs. When 0.05 ⁇ M2 ⁇ 0.18, the carbon The matrix has better compression resistance.
  • N2 is the change in compaction density of the carbon matrix when the carbon matrix is pressed for the 1st and 20th times. It is used to represent the degree of deformation of the silicon-carbon composite material under multiple pressures. When 0.08 ⁇ N2 ⁇ 0.2, it is beneficial to increase the C2 value. It satisfies 0.8 ⁇ C2 ⁇ 2, thus making the carbon matrix have better flexibility.
  • the carbon matrix sequentially includes a first region and a second region in the direction extending from the center to the surface.
  • the volume of the second region is twice the volume of the first region.
  • the first region contains pores with a pore size of 2 to 1000 nm.
  • the ratio of the number of pores to the number of pores in the second region containing pores with a diameter of 2 to 1000 nm is >1.
  • the ratio of the number of pores having a pore diameter of 2 to 500 nm in the first region to the number of pores having a pore diameter of 2 to 500 nm in the second region is >1.
  • the ratio of the number of pores with a pore diameter of 2 to 200 nm in the first region to the number of pores with a pore diameter of 2 to 200 nm in the second region is >1.
  • the C2 value can be made to satisfy 0.8 ⁇ C2 ⁇ 2.
  • Figure 1 is a schematic structural diagram of a vehicle according to some embodiments of the present application.
  • Figure 2 is a schematic diagram of the exploded structure of a battery according to some embodiments of the present application.
  • Figure 3 is a schematic diagram of the exploded structure of a battery cell according to some embodiments of the present application.
  • Figure 4 is a schematic structural diagram of carbon matrix particles according to some embodiments of the present application.
  • an embodiment means that a particular feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application.
  • the appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those skilled in the art understand, both explicitly and implicitly, that the embodiments described herein may be combined with other embodiments.
  • multiple refers to more than two (including two).
  • multiple groups refers to two or more groups (including two groups), and “multiple pieces” refers to It is more than two pieces (including two pieces).
  • Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles and electric cars, as well as in many fields such as military equipment and aerospace. . As the application fields of power batteries continue to expand, their market demand is also constantly expanding.
  • the silicon anode material undergoes severe volume expansion during actual charging and discharging. After a certain number of cycles, the electrode piece becomes pulverized and peeled off, causing battery performance to plummet.
  • nanometer silicon particles have smaller stress and strain.
  • nanometer silicon particles have problems in preparation, dispersion and Problems such as high surface activity make processing difficult; on the other hand, it is compounded with a carbon matrix, such as using graphite, hard carbon, graphene or carbon nanotubes to isolate and coat silicon or to reserve expansion space for active silicon.
  • Silicon enhances structural stability through a composite carbon matrix.
  • Common composite methods include liquid phase coating (asphalt, resin, etc.) and gas phase coating (acetylene and various alkanes).
  • the carbon layers formed are all rigid carbon structures. This type of structure It is prone to rupture when the stress exceeds the threshold, and it is inelastic and collapses during the shrinkage process. The stress range is extremely limited.
  • the inventor in order to alleviate the expansion of the silicon anode material and increase the shrinkage of the silicon anode material, the inventor has designed a silicon-carbon composite material after in-depth research.
  • the silicon material is at least partially distributed in a carbon matrix with a cross-linked pore structure.
  • C1 is the multiple of the rebound deformation amount of the silicon-carbon composite material to the compression deformation amount, which is used to express the flexibility of the silicon-carbon composite material.
  • the silicon-carbon composite material has good flexibility. On the one hand, it can reduce the influence of silicon expansion stress on the overall silicon-carbon composite material.
  • the carbon matrix frame has a certain degree of shrinkage. It can further accommodate and release residual stress, thereby maintaining the overall stability of the silicon-carbon composite material.
  • the battery mentioned in the embodiments of this application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.
  • Batteries generally include a battery box for packaging one or more battery cells.
  • the battery box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.
  • the battery cells may include lithium ion secondary battery cells, lithium ion primary battery cells, lithium sulfur battery cells, sodium lithium ion battery cells, sodium ion battery cells or magnesium ion battery cells, etc., embodiments of the present application There is no limit to this.
  • the battery cell may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes, and the embodiments of the present application are not limited to this. Battery cells are generally divided into three types according to packaging methods: cylindrical battery cells, prismatic battery cells and soft-pack battery cells.
  • the battery cell includes an electrode assembly and an electrolyte.
  • the electrode assembly consists of a positive electrode plate, a negative electrode plate and a separator. Battery cells mainly rely on the movement of metal ions between the positive and negative electrodes to work.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer.
  • the positive electrode active material layer is coated on the surface of the positive electrode current collector.
  • the positive electrode current collector that is not coated with the positive electrode active material layer protrudes from the positive electrode collector that is coated with the positive electrode active material layer. Fluid, the cathode current collector that is not coated with the cathode active material layer serves as the cathode tab.
  • the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganate, etc.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer.
  • the negative electrode active material layer is coated on the surface of the negative electrode current collector.
  • the negative electrode current collector that is not coated with the negative electrode active material layer protrudes from the negative electrode collector that is coated with the negative electrode active material layer.
  • Fluid, the negative electrode current collector that is not coated with the negative electrode active material layer is used as the negative electrode tab.
  • the material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon.
  • the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together.
  • the material of the isolation film can be polypropylene (PP) or polyethylene (Polyethylene, PE).
  • the electrode assembly may have a rolled structure or a laminated structure, and the embodiments of the present application are not limited thereto.
  • the battery cell also includes a current collecting member, which is used to electrically connect the tabs of the battery cell and the electrode terminals to transport electric energy from the electrode assembly to the electrode terminal, and through the electrode terminal to the outside of the battery cell; and more
  • the battery cells are electrically connected through bus components to realize series, parallel or mixed connection of multiple battery cells.
  • the battery also includes a sampling terminal and a battery management system.
  • the sampling terminal is connected to the bus component and is used to collect battery cell information, such as voltage or temperature, etc.
  • the sampling terminal transmits the collected battery cell information to the battery management system.
  • the battery management system detects that the battery cell information exceeds the normal range, it will limit the battery output power to achieve safety protection.
  • the electrical devices suitable for using batteries described in the embodiments of the present application can be in various forms, such as mobile phones, portable devices, laptops, battery cars, electric cars, ships, spacecrafts, electric toys and electric toys.
  • Tools, etc., for example, spacecraft include airplanes, rockets, space shuttles and spaceships, etc.
  • Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric aircraft toys, etc.
  • Power tools include metal cutting power tools, grinding power tools, assembly power tools and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers.
  • the battery cells and batteries described in the embodiments of the present application are not limited to the above-described electrical devices, but can also be applied to all electrical devices using battery cells and batteries. However, for the sake of simplicity of description, the following embodiments All are explained using electric vehicles as an example.
  • the vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.
  • the battery 100 is disposed inside the vehicle 1000 , and the battery 100 may be disposed at the bottom, head, or tail of the vehicle 1000 .
  • the battery 100 may be used to power the vehicle 1000 , for example, the battery 100 may serve as an operating power source for the vehicle 1000 .
  • the vehicle 1000 may also include a controller 200 and a motor 300.
  • the controller 200 is used to control the battery 100 to provide power to the motor 300, for example, for the starting, navigation and operating power requirements of the vehicle 1000.
  • the battery 100 can not only be used as an operating power source for the vehicle 1000 , but can also be used as a driving power source for the vehicle 1000 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000 .
  • the battery 100 includes a case 10 and battery cells 20 , and the battery cells 20 are accommodated in the case 10 .
  • the box 10 is used to provide an accommodation space for the battery cells 20, and the box 10 can adopt a variety of structures.
  • the box 10 may include a first part 11 and a second part 12 , the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define a space for accommodating the battery cells 20 of accommodation space.
  • the second part 12 may be a hollow structure with one end open, and the first part 11 may be a plate-like structure.
  • the first part 11 covers the open side of the second part 12 so that the first part 11 and the second part 12 jointly define a receiving space.
  • the first part 11 and the second part 12 may also be hollow structures with one side open, and the open side of the first part 11 is covered with the open side of the second part 12.
  • the box 10 formed by the first part 11 and the second part 12 can be in various shapes, such as cylinder, rectangular parallelepiped, etc.
  • the battery 100 there may be a plurality of battery cells 20, and the plurality of battery cells 20 may be connected in series, in parallel, or in mixed connection.
  • Mixed connection means that the plurality of battery cells 20 are connected in series and in parallel.
  • the plurality of battery cells 20 can be directly connected in series or in parallel or mixed together, and then the whole composed of the plurality of battery cells 20 can be accommodated in the box 10 ; of course, the battery 100 can also be a plurality of battery cells 20 First, the battery modules are connected in series, parallel, or mixed to form a battery module, and then multiple battery modules are connected in series, parallel, or mixed to form a whole, and are accommodated in the box 10 .
  • the battery 100 may also include other structures.
  • the battery 100 may further include a bus component for realizing electrical connections between multiple battery cells 20 .
  • Each battery cell 20 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto.
  • the battery cell 20 may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes.
  • FIG. 3 is a schematic diagram of an exploded structure of a battery cell provided by some embodiments of the present application.
  • the battery cell 20 refers to the smallest unit that constitutes the battery. As shown in FIG. 3 , the battery cell 20 includes an end cover 21 , a case 22 , an electrode assembly 23 and other functional components.
  • the end cap 21 refers to a component that covers the opening of the case 22 to isolate the internal environment of the battery cell 20 from the external environment.
  • the shape of the end cap 21 can be adapted to the shape of the housing 22 to fit the housing 22 .
  • the end cap 21 can be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap 21 is less likely to deform when subjected to extrusion and collision, so that the battery cell 20 can have higher durability. Structural strength and safety performance can also be improved.
  • the end cap 21 may be provided with functional components such as electrode terminals. The electrode terminals may be used to electrically connect with the electrode assembly 23 for outputting or inputting electrical energy of the battery cell 20 .
  • the end cap 21 may also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold.
  • the end cap 21 can also be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not particularly limited in the embodiment of the present application.
  • an insulating member may also be provided inside the end cover 21 , and the insulating member may be used to isolate the electrical connection components in the housing 22 from the end cover 21 to reduce the risk of short circuit.
  • the insulating member may be plastic, rubber, etc.
  • the housing 22 is a component used to cooperate with the end cover 21 to form an internal environment of the battery cell 20 , wherein the formed internal environment can be used to accommodate the electrode assembly 23 , electrolyte, and other components.
  • the housing 22 and the end cover 21 may be independent components, and an opening may be provided on the housing 22.
  • the end cover 21 covers the opening at the opening to form the internal environment of the battery cell 20.
  • the end cover 21 and the housing 22 can also be integrated.
  • the end cover 21 and the housing 22 can form a common connection surface before other components are put into the housing. When it is necessary to encapsulate the inside of the housing 22 At this time, the end cover 21 covers the housing 22 again.
  • the housing 22 can be of various shapes and sizes, such as rectangular parallelepiped, cylinder, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 23 .
  • the housing 22 may be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not particularly limited in the embodiments of the present application.
  • the electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur.
  • One or more electrode assemblies 23 may be contained within the housing 22 .
  • the electrode assembly 23 is mainly formed by winding or stacking positive electrode sheets and negative electrode sheets, and a separator is usually provided between the positive electrode sheets and the negative electrode sheets.
  • the portions of the positive electrode sheet and the negative electrode sheet that contain active material constitute the main body of the electrode assembly, and the portions of the positive electrode sheet and the negative electrode sheet that do not contain active material each constitute the tabs.
  • the positive electrode tab and the negative electrode tab can be located together at one end of the main body or respectively located at both ends of the main body. During the charging and discharging process of the battery, the positive active material and negative active material react with the electrolyte, and the tabs are connected to the electrode terminals to form a current loop.
  • the present application provides a silicon-carbon composite material, including: a carbon matrix and a silicon material.
  • the carbon matrix has a cross-linked pore structure inside, and the silicon material is at least partially distributed in the cross-linked pore structure.
  • the flexibility C1 value of the silicon-carbon composite material satisfies 0.4 ⁇ C1 ⁇ 2. The flexibility is measured by the following method: apply a pressure of 2t to the silicon-carbon composite material, hold the pressure for 10 seconds, and release the pressure for 100 seconds.
  • the carbon matrix is a carrier for supporting silicon materials and has a porous structure.
  • Silicon material is an element or compound that can provide silicon atoms.
  • the cross-linked pore structure refers to the cross-linked structure formed by interconnected pores inside the carbon matrix.
  • the C1 value may be 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0.
  • testing method for detecting flexibility in this application is based on GB/T 24533-2009.
  • the test process is that during the external compression process, as the powder moves and deforms, the gaps are filled, and the contact area between particles increases, which causes attraction between atoms and strengthens the mechanical fit between particles, thereby forming a compact with a certain density. .
  • the silicon material is at least partially distributed in the carbon matrix with a cross-linked pore structure.
  • C1 in this application is the multiple of the rebound deformation amount of the silicon-carbon composite material to the compression deformation amount, which is used to indicate the flexibility of the silicon-carbon composite material.
  • the silicon-carbon composite material has good flexibility. On the one hand, it can reduce the influence of silicon expansion stress on the overall silicon-carbon composite material.
  • the carbon matrix frame has a certain degree of shrinkage. It can further accommodate and release residual stress, thereby maintaining the overall stability of the silicon-carbon composite material.
  • the silicon-carbon composite material When the C1 value satisfies 0.8 ⁇ C1 ⁇ 2, the silicon-carbon composite material has good flexibility. On the one hand, it can reduce the influence of silicon expansion stress on the overall silicon-carbon composite material. On the other hand, the carbon matrix frame has a certain degree of shrinkage. It can further accommodate and release residual stress, thereby maintaining the overall stability of the silicon-carbon composite material.
  • the M1 value may be 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, or 0.18.
  • the N1 value may be 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19 or 0.2.
  • M1 in this application is the change in compacted density of the silicon-carbon composite material after the first and 20th pressure relief. It is used to indicate the deformation degree of the silicon-carbon composite material after multiple pressure reliefs, and when 0.05 ⁇ M1 ⁇ 0.18 , silicon-carbon composite materials have better compression resistance.
  • N1 is the change in compaction density of the silicon-carbon composite material when the pressure is applied for the first and 20th times. It is used to indicate the degree of deformation of the silicon-carbon composite material under multiple pressures. When 0.04 ⁇ N1 ⁇ 0.2, it is beneficial to make The C1 value satisfies 0.8 ⁇ C1 ⁇ 2, which makes the silicon carbon composite material have better flexibility.
  • FIG 4 is a schematic structural diagram of carbon matrix particles in some embodiments of the present application.
  • the carbon matrix sequentially includes a first region and a second region in a direction extending from the center to the surface, and the carbon matrix is composed of a first region and a second region.
  • the volume of the second region is twice the volume of the first region.
  • the ratio of the number of pores with a pore diameter of 2 nm to 1000 nm in the second region and the number of pores with a pore diameter of 2 nm to 1000 nm in the second region is >1.
  • the first region is the region in the middle of the carbon matrix
  • the second region is the region covering the first region in the carbon matrix.
  • the first region and the second region can be calculated and divided.
  • the carbon matrix particles are approximated to be spherical
  • the carbon matrix particles are approximated to be spherical.
  • the radius of the matrix particles is calculated into two identical volumes and divided into a first region and a second region.
  • the ratio of the number of pores with a pore diameter of 2 nm to 500 nm in the first region and the number of pores with a pore diameter of 2 nm to 500 nm in the second region is >1.
  • the ratio of the number of pores with a pore diameter of 2 nm to 200 nm in the first region and the number of pores with a pore diameter of 2 nm to 200 nm in the second region is >1.
  • the carbon matrix particles 400 are spherical or quasi-spherical.
  • the carbon matrix particles 400 are divided into 10 equal parts according to the distance along the direction extending from the center to the surface, thereby obtaining 10 regions. Among the 10 regions, the largest The area within is the area including the center.
  • the first area to the seventh area from the innermost area is the first area 410, and the three outermost areas (the 8th area to the 10th area) are the second area. 420.
  • the specific surface area SSA value of the silicon-carbon composite material satisfies 1g/cm2 ⁇ SSA ⁇ 10g/cm2.
  • the specific surface area SSA value of the silicon-carbon composite material can be 1g/cm2, 2g/cm2, 3g/cm2, 4g/cm2, 5g/cm2, 6g/cm2, 7g/cm2, 8g/cm2, 9g/cm2 or 10g/cm2.
  • the silicon-carbon composite material When the specific surface area SSA value of the silicon-carbon composite material satisfies 1g/cm2 ⁇ SSA ⁇ 10g/cm2, the silicon-carbon composite material has fewer surface defects, which is conducive to the formation of a stable SEI film and the reduction of irreversible lithium ion loss.
  • the specific surface area SSA value of the silicon-carbon composite material satisfies 3g/cm2 ⁇ SSA ⁇ 7g/cm2.
  • the silicon carbon composite material has Dv10 ⁇ 5 ⁇ m, Dv50 ⁇ 8 ⁇ m, Dv90 ⁇ 20 ⁇ m, and (Dv90-Dv10)/Dv50 ⁇ 1.6.
  • the Dv10 value of the silicon carbon composite material may be 0.1 ⁇ m, 0.5 ⁇ m, 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m or 5 ⁇ m.
  • the Dv50 value of the silicon carbon composite may be 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m or 8 ⁇ m.
  • the Dv90 value of the silicon carbon composite may be 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 10 ⁇ m, 11 ⁇ m, 12 ⁇ m, 13 ⁇ m, 14 ⁇ m, 15 ⁇ m, 16 ⁇ m, 17 ⁇ m, 18 ⁇ m, 19 ⁇ m or 20 ⁇ m.
  • the powder compacted density PD of the silicon-carbon composite material at 5t is ⁇ 1.1 g/cm3.
  • the PD value of the powder compaction density of silicon carbon composite material at 5t can be 0.1g/cm3, 0.2g/cm3, 0.3g/cm3, 0.4g/cm3, 0.5g/cm3, 0.6g/cm3, 0.7 g/cm3, 0.8g/cm3, 0.9g/cm3, 1g/cm3 or 1.1g/cm3.
  • Silicon-carbon composite materials with a powder compaction density of PD ⁇ 1.1g/cm3 at 5t have a porous structure.
  • the silicon material includes any one or more of silicon oxide compounds, silicon element and alloy silicon.
  • Silicon material has the advantages of high energy density, low lithium insertion potential and wide source. Silicon oxide compounds, silicon elemental and alloy silicon can be loaded in the pores of the carbon matrix to produce silicon-carbon composite materials, which are used to make negative electrode materials and energy density. High battery.
  • the present application also provides a method for preparing the silicon-carbon composite material of the above embodiment, which includes: subjecting the raw materials to a first heat treatment to obtain a solid resin, and subjecting the pulverized solid resin to a second heat treatment.
  • the neutral solvent is volatilized to obtain a carbon precursor.
  • the carbon precursor is subjected to pyrolysis and carbonization to obtain a carbon matrix.
  • the silicon material is compounded in the cross-linked pore structure of the carbon matrix.
  • Raw materials include resin, porogen and neutral solvent.
  • the raw materials are resin and porogen dispersed in neutral solvent.
  • Solid resin is a substance that appears in a solid state and includes a resin, a porogen, and a neutral solvent.
  • the pulverized solid resin is produced by sequentially undergoing coarse crushing, fine crushing and grinding steps of the solid resin, so that the final carbon matrix has Dv10 ⁇ 5 ⁇ m, Dv50 ⁇ 8 ⁇ m, Dv90 ⁇ 20 ⁇ m, and (Dv90-Dv10)/Dv50 ⁇ 1.6.
  • coarse breaking includes using rollers and cyclone mills to coarsely break bulk materials, so that the bulk materials can be turned into small blocks with an average diameter of about 1cm.
  • Fine crushing includes using a stone disc mechanical grinder for fine crushing.
  • the first stage is crushing at 700-1000r/min.
  • the second stage is accelerating fine crushing at a rotation speed of 2000-2500r/min to collect materials. Subsequently, the second-stage crushing process is repeated for 2 ⁇ Three times, fine materials were obtained, with particle size less than 0.15mm.
  • Grinding includes grinding through an airflow mill, exhausting the air inside the cavity, adjusting the air pressure valve to the maximum value (usually 0.5Mpa), and then adjusting the air inlet pressure, crushing pressure and feed pressure to 0.36Mpa and 0.36Mpa respectively. , and 0.34Mpa. Further, the target sample is sucked into the abrasive chamber for crushing. After 5 minutes, the gas valve and vibration switch are closed to collect the ground sample.
  • the raw materials including resin, porogen and neutral solvent can be formed into a solid resin through the first heat treatment, which is beneficial to subsequent processing.
  • the pulverized solid resin is then subjected to a second heat treatment to volatilize the solvent so that the pores are interconnected to form a cross-linked pore structure, thereby obtaining a carbon precursor.
  • the carbon precursor is subjected to pyrolysis carbonization treatment to carbonize organic matter to obtain a carbon matrix.
  • the preparation method of the silicon-carbon composite material of the present application uses an in-situ porogenic method.
  • the obtained carbon matrix has a cross-linked pore structure evenly distributed inside and on the surface, and the pore diameter is suitable, which is conducive to filling the pores of the carbon matrix with silicon material. and dispersion, thereby producing silicon-carbon composite materials with a more stable structure.
  • the raw materials are first transferred to a mold and left to rest.
  • it includes first injecting 2 tons of softened water into the pickling kettle, adding 1,000kg of the target material that needs to be pickled, selecting the mode to remove surface floating carbon, and draining the black water; repeat the above steps until the discharged softened water is clarified, and then add 3 to 5 wt% of hydrochloric acid.
  • the input amount refers to the initial pH value of the material and sets the input amount in stages; steam cooking for more than 0.5 hours, add purified water and overflow part of the black water; turn on the centrifuge and run at low speed; then open the discharge valve and pass the water and materials into the centrifugal dehydration cavity, dehydrate for 10 minutes; increase the centrifuge to medium speed, spray reverse osmosis water into the water pipe for rinsing for 20 minutes, turn to high-speed centrifugal dehydration for 20 minutes; after the material is poured out, transfer to the drying oven for further dehydration and drying until the water content is less than 5wt% .
  • fine powder and metal impurities are overflowed to remove iron and magnetism, and the dry materials are further passed through a rotary vibrating screen for screening and powder collection.
  • the method of compounding the silicon material in the cross-linked pore structure of the carbon matrix includes chemical vapor deposition.
  • the treatment temperature of the second heat treatment is 150-400°C, and the treatment time is at least 10 hours.
  • the treatment temperature of the second heat treatment may be 150°C, 180°C, 200°C, 220°C, 250°C, 280°C, 300°C, 330°C, 350°C, 370°C or 400°C.
  • the treatment time of the second heat treatment may be 10h, 12h, 14h, 16h, 18h or 20h.
  • the mass ratio of resin to neutral solvent is 1:10 to 10:1, and the mass ratio of resin to porogen is 1:5 to 10:1.
  • the mass ratio of resin and neutral solvent can be 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, 1 :1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1.
  • the mass ratio of resin and porogen can be 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, 6 :1, 7:1, 8:1, 9:1 or 10:1.
  • the resin includes any one or more of phenolic resin, epoxy resin and polyurethane.
  • the neutral solvent includes any one or more of methanol, ethanol, ethylene glycol, polyethylene glycol, glycerin and isopropyl alcohol.
  • porogens include potassium chloride, sodium chloride, zinc chloride, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, phosphoric acid, sodium acetate, zinc acetate, nickel acetate, and acetic acid Any one or more types of ammonium.
  • the first heat treatment includes standing at 60 to 150°C for at least 10 hours.
  • the treatment temperature of the first heat treatment may be 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C or 150°C.
  • the treatment time of the first heat treatment may be 10h, 12h, 14h, 16h, 18h or 20h.
  • the pyrolysis carbonization treatment includes sintering at 600 to 1600°C for 1 to 3 hours.
  • the processing temperature of the pyrolysis carbonization treatment may be 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1100°C, 1150°C, 1200°C , 1250°C, 1300°C, 1350°C, 1400°C, 1450°C or 1500°C.
  • the treatment time of the pyrolytic carbonization treatment may be 1 h, 1.5 h, 2 h, 2.5 h or 3 h.
  • Selecting an appropriate temperature for pyrolysis carbonization treatment is beneficial to obtaining a carbon matrix with a cross-linked pore structure evenly distributed inside and on the surface.
  • the temperature of the pyrolysis carbonization treatment is 800 to 1000°C.
  • the present application also provides a carbon matrix, which has a cross-linked pore structure inside.
  • the flexibility C2 value of the carbon matrix satisfies 0.8 ⁇ C2 ⁇ 2.
  • the C2 value may be 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0.
  • C2 in this application is the multiple of the rebound deformation amount of the carbon matrix to the compression deformation amount, which is used to indicate the flexibility of the carbon matrix.
  • the C2 value satisfies 0.8 ⁇ C2 ⁇ 2, the carbon matrix has good flexibility.
  • M2 is defined as P6-P5
  • N2 is defined as P8-P7, 0.04 ⁇ M2 ⁇ 0.18, 0.04 ⁇ N2 ⁇ 0.08.
  • the M2 value may be 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, or 0.18.
  • the N2 value may be 0.04, 0.05, 0.06, 0.07 or 0.08.
  • M2 in this application is the change in compacted density of the carbon matrix after the first and 20th pressure relief. It is used to indicate the degree of deformation of the silicon-carbon composite material after multiple pressure reliefs.
  • N2 is the change in compaction density of the carbon matrix when the carbon matrix is pressed for the 1st and 20th times. It is used to represent the degree of deformation of the silicon-carbon composite material under multiple pressures.
  • 0.08 ⁇ N2 ⁇ 0.2 it is beneficial to increase the C2 value. It satisfies 0.8 ⁇ C2 ⁇ 2, thus making the carbon matrix have better flexibility.
  • the carbon matrix sequentially includes a first region and a second region in a direction extending from the center to the surface.
  • the volume of the second region is twice the volume of the first region.
  • the ratio of the number of pores with a pore diameter of 2 to 1000 nm and the number of pores with a pore diameter of 2 to 1000 nm in the second region is >1.
  • the C2 value can be made to satisfy 0.8 ⁇ C2 ⁇ 2.
  • the number of pores with a pore diameter of 2 to 1000 nm in the first region and the number of pores with a pore diameter of 2 to 1000 nm in the second region can be observed based on the scanning electron microscope image of the cross section of the carbon substrate.
  • the ratio of the number of pores having a pore diameter of 2 to 500 nm in the first region to the number of pores having a pore diameter of 2 to 500 nm in the second region is >1.
  • the ratio of the number of pores with a pore diameter of 2 to 200 nm in the first region to the number of pores with a pore diameter of 2 to 200 nm in the second region is >1.
  • Embodiments of the present application provide a silicon-carbon composite material and a preparation method thereof, anode material, anode plate, electrode assembly, battery and carbon matrix.
  • the temperature of the first heat treatment is 80°C and the time is 10 hours; then the solid resin is subjected to coarse crushing and fine crushing in sequence. After crushing and grinding, the pulverized solid resin is obtained.
  • the pulverized solid resin is subjected to a second heat treatment to volatilize the neutral solvent to obtain a carbon precursor.
  • the temperature of the second heat treatment is 180°C and the time is 10 hours; the carbon precursor is
  • the carbon matrix is obtained by pyrolysis and carbonization treatment.
  • the temperature of the pyrolysis carbonization treatment is 1000°C and the time is 2 hours.
  • the obtained carbon matrix is then subjected to impurity removal, demagnetization and classification to obtain a carbon matrix that meets the particle size requirements.
  • the ratio of the number of pores with a pore diameter of 2 nm to 1000 nm in the first region of the carbon matrix to the number of pores with a pore diameter of 2 nm to 1000 nm in the second region is 5.3, the C2 value is 1.40, the M2 value is 0.05, and the N2 value is 0.07.
  • Nano-silicon is evenly dispersed in the carbon matrix through chemical vapor deposition to prepare silicon-carbon composite materials.
  • the C1 value of silicon-carbon composite material is 1.7, M1 value is 0.06, N1 value is 0.1, specific surface area SSA is 6g/cm2, Dv10 is 3.2 ⁇ m, Dv50 is 7 ⁇ m, Dv90 is 15 ⁇ m, (Dv90-Dv10)/Dv50 is 1.7 .
  • the negative electrode material 25wt% silicon carbon composite + 75wt% artificial graphite
  • conductive agent and adhesive in proportion to form a slurry, in which the negative electrode content is not less than 95.5wt% and the adhesive is sodium carboxymethylcellulose , the conductive agent is conductive carbon black, the slurry is evenly coated on the copper foil, and vacuum dried at 80°C to make a negative electrode sheet (water content ⁇ 5ppm).
  • the prepared negative electrode sheet is assembled in a glove box for battery assembly.
  • the metal lithium sheet is used as the counter electrode.
  • Electrode sheet Stack the positive electrode sheet, isolation film, and negative electrode sheet in order, and obtain the electrode assembly after winding. Put the electrode assembly into the outer package, add the above-mentioned electrolyte, and go through the processes of packaging, standing, forming, aging, etc. , get the secondary battery.
  • the comparative example of this application provides a silicon-carbon composite material and its preparation method, anode material, anode plate, electrode assembly, battery and carbon matrix.
  • the ratio of the number of pores with a pore diameter of 2 nm to 1000 nm in the first region of the carbon matrix to the number of pores with a pore diameter of 2 nm to 1000 nm in the second region is 3, the C2 value is 0.5, the M2 value is 0.08, and the N2 value is 0.04.
  • Nano-silicon is evenly dispersed in the carbon matrix through chemical vapor deposition to prepare silicon-carbon composite materials.
  • the C1 value of the silicon carbon composite material is 0.29, the M1 value is 0.14, the N1 value is 0.04, the specific surface area SSA is 7g/cm2, Dv10 is 3 ⁇ m, Dv50 is 7.8 ⁇ m, Dv90 is 15.7 ⁇ m, (Dv90-Dv10)/Dv50 is 1.63.
  • the negative electrode material 25wt% silicon carbon composite + 75wt% artificial graphite
  • conductive agent and adhesive in proportion to form a slurry, in which the negative electrode content is not less than 95.5wt% and the adhesive is sodium carboxymethylcellulose , the conductive agent is conductive carbon black, the slurry is evenly coated on the copper foil, and vacuum dried at 80°C to make a negative electrode sheet (water content ⁇ 5ppm).
  • the prepared negative electrode sheet is assembled in a glove box for battery assembly.
  • the metal lithium sheet is used as the counter electrode.
  • Electrode sheet Stack the positive electrode sheet, isolation film, and negative electrode sheet in order, and obtain the electrode assembly after winding. Put the electrode assembly into the outer package, add the above-mentioned electrolyte, and go through the processes of packaging, standing, forming, aging, etc. , get the secondary battery.
  • the ratio in Table 1 is the ratio of the number of pores with a pore diameter of 2 nm to 1000 nm in the first region to the number of pores with a pore diameter of 2 nm to 1000 nm in the second region.
  • Example 1 Project Cycles Example 1 1350 Example 2 1220 Example 3 1256 Example 4 1300 Example 5 1320 Example 6 1324 Example 7 1345 Example 8 1360
  • Example 9 1250 Example 10 1325 Example 11 1350 Example 12 1335 Example 13 1322 Example 14 1345 Example 15 1278 Example 16 1390 Example 17 1378 Example 18 1280 Example 19 1240 Example 20 1235 Example 21 1270 Example 22 1210 Example 23 1202 Example 24 920 Example 25 880 Comparative example 1 950 Comparative example 2 856 Comparative example 3 900

Abstract

一种硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池、用电装置和碳基体，属于电池技术领域。硅碳复合材料包括碳基体和硅材料，碳基体内部具有交联型孔结构，硅材料至少部分分布于交联型孔结构中。硅碳复合材料的柔性度 C1值满足0.4≤C1≤2。Cl 为硅碳复合材料的反弹形变量对压缩形变量的倍数，用于表示硅碳复合材料的柔性度。当C1 值满足0.4≤C1≤2时，硅碳复合材料具有较好的柔性度，一方面可以减少硅碳复合材料整体受硅膨胀应力的影响，另一方面碳基体框架具有一定的收缩性，可进一步容纳和释放残余应力，从而维护硅碳复合材料整体的稳定性。

Description

硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池、用电装置和碳基体 技术领域
本申请涉及电池技术领域，具体而言，涉及一种硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池、用电装置和碳基体。
背景技术
硅负极材料具有能量密度高、嵌锂电位低及来源广泛等优势，有望成为下一代负极材料。然而硅负极材料在实际充放电时存在剧烈的体积膨胀，一定次数循环后极片发生粉化和剥落，电池性能因此发生跳水。
发明内容
鉴于上述问题，本申请提供一种硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池、用电装置和碳基体，能够减弱硅碳复合材料受硅膨胀应力的影响。
第一方面，本申请提供了一种硅碳复合材料，包括：碳基体和硅材料，碳基体内部具有交联型孔结构，硅材料至少部分分布于交联型孔结构中。硅碳复合材料的柔性度C1值满足0.4≤C1≤2，柔性度通过以下方法测得：对硅碳复合材料施加压力2t，保压10s，卸压100s，反复保压和卸压20次后，分别记录第1次保压时的压实密度P1、第20次保压时的压实密度P2、第1次卸压时的压实密度P3和第20次卸压时的压实密度P4，计算C1＝(P4-P3)/(P2-P1)。
本申请实施例的技术方案中，硅材料至少部分分布于具有交联型孔结构的碳基体中，本申请的C1为硅碳复合材料的反弹形变量对压缩形变量的倍数，用于表示硅碳复合材料的柔性度。当C1值满足0.4≤C1≤2时，硅碳复合材料具有较好的柔性度，一方面可以减少硅碳复合材料整体受硅膨胀应力的影响，另一方面碳基体框架具有一定的收缩性，可进一步容纳和释放残余应力，从而维护硅碳复合材料整体的稳定性。
在一些实施例中，0.8≤C1≤2。当C1值满足0.8≤C1≤2时，硅碳复合材料具有较好的柔性度，一方面可以减少硅碳复合材料整体受硅膨胀应力的影响，另一方面碳基体框架具有一定的收缩性，可进一步容纳和释放残余应力，从而维护硅碳复合材料整体的稳定性。
在一些实施例中，定义P2-P1为M1，P4-P3＝N1，0.05≤M1≤0.18，0.08≤N1≤0.2。可选地，0.08≤M1≤0.15，0.10≤N1≤0.18。本申请的M1为硅碳复合材料第1次和第20次卸压后的压实密度变化量，用于表示硅碳复合材料多次卸压后的形变程度，且当0.05≤M1≤0.18时，硅碳复合材料的抗压性能较优。N1为硅碳复合材料第1次和第20次施压时压实密度变化量，用于表示硅碳复合材料多次受压力发生的形变程度，且当0.04≤N1≤0.2时，有利于使得C1值满足0.8≤C1≤2，进而使硅碳复合材料具有较好的柔性度。
在一些实施例中，碳基体沿由中心向表面延伸的方向依次包括第一区域和第二区域，且碳基体由第一区域和第二区域组成，第二区域的体积为第一区域体积的2倍，第一区域中含有2nm～1000nm孔径的孔的数量与第二区域中含有2nm～1000nm孔径的孔的数量的比值＞1。可选地，第一区域中含有2nm～500nm孔径的孔的数量与第二区域中含有2nm～500nm孔径的孔的数量的比值＞1。可选地，第一区域中含有2nm～200nm孔径的孔的数量与第二区域中含有2nm～200nm孔径的孔的数量的比值＞1。位于碳基体靠近中心位置的第一区域的2nm～1000nm的孔越多，可以内靠近中心位置的孔中沉积更多的硅材料，硅碳复合材料的柔性度越高，即硅碳复合材料的C1值越大；当第一区域中含有2nm～1000nm孔径的孔的数量与第二区域中含有2nm～1000nm孔径的孔的数量的比值＞1时，可以使得C1值满足0.4≤C1≤2。
在一些实施例中，硅碳复合材料的比表面积SSA值满足1g/cm2≤SSA≤10g/cm2。可选地，硅碳复合材料的比表面积SSA值满足3g/cm2≤SSA≤7g/cm2。当硅碳复合材料的比表面积 SSA值满足1g/cm2≤SSA≤10g/cm2时，硅碳复合材料的表面缺陷少，有利于形成稳定的SEI膜，减少不可逆锂离子损失。
在一些实施例中，硅碳复合材料的Dv10≤5μm，Dv50≤8μm，Dv90≤20μm，且(Dv90-Dv10)/Dv50≥1.6。有利于提高硅碳复合材料应用时的压实密度，提高活性物颗粒的电接触，从而提高负极极片的导电率。
在一些实施例中，硅碳复合材料5t下的粉体压实密度PD≤1.1g/cm3。5t下的粉体压实密度PD≤1.1g/cm3的硅碳复合材料具有多孔结构。
在一些实施例中，硅材料包括硅氧化合物、硅单质和合金硅中的任意一种或多种。硅材料具有能量密度高、嵌锂电位低及来源广泛等优点，硅氧化合物、硅单质和合金硅能够负载于碳基体的孔中制得硅碳复合材料，用于制成负极材料和能量密度高的电池。
第二方面，本申请提供了一种上述实施例的硅碳复合材料的制备方法，其包括：将原料经过第一热处理制得固态树脂，将粉碎后的固态树脂经过第二热处理使中性溶剂挥发，制得碳前驱体，将碳前驱体经过热解碳化处理，制得碳基体，将硅材料复合在碳基体的交联型孔结构中。原料包括树脂、致孔剂和中性溶剂。
本申请实施例的技术方案中，将包括树脂、致孔剂和中性溶剂的原料经第一热处理能够形成固态树脂，有利于后续加工。再将粉碎后的固态树脂经第二热处理使溶剂挥发使得孔相互连通形成交联型孔结构，制得碳前驱体。将碳前驱体经过热解碳化处理使得有机物碳化制得碳基体。本申请的硅碳复合材料的制备方法通过原位致孔的方法，所得碳基体内部和表面均分布有交联型孔结构，且孔的孔径合适，有利于硅材料在碳基体的孔中填充和分散，从而制得结构更为稳定的硅碳复合材料。
在一些实施例中，第二热处理的处理温度为150～400℃，处理时间为至少10h。选择合适的第二热处理的处理温度和处理时间有利于使溶剂挥发使得孔相互连通形成交联型孔结构，如果温度太高，会使得制得的硅碳复合材料的孔变大，硅碳复合材料变脆，硅碳复合材料C1值变小。
在一些实施例中，树脂和中性溶剂的质量比为1:10～10:1，树脂和致孔剂的质量比为1:5～10:1。可选地，树脂包括酚醛树脂、环氧树脂和聚氨酯中的任意一种或多种。可选地，中性溶剂包括甲醇、乙醇、乙二醇、聚乙二醇、丙三醇和异丙醇中的任意一种或多种。可选地，致孔剂包括氯化钾、氯化钠、氯化锌、氢氧化钠、氢氧化钾、碳酸钠、碳酸钾、碳酸氢钠、磷酸、醋酸钠、醋酸锌、醋酸镍和醋酸铵中的任意一种或多种。选择合适的树脂和中性溶剂的配比有利于控制制得的硅碳复合材料中的孔的数量和大小。
在一些实施例中，第一热处理包括在60～150℃下静置至少10h。选择合适的第一热处理的处理温度和处理时间有利于获得固态树脂。
在一些实施例中，热解碳化处理包括在600～1600℃下烧结1～3h。可选地，热解碳化处理的温度为800～1000℃。选择合适的热解碳化的处理温度和处理时间有利于获得内部和表面均分布有交联型孔结构的碳基体。
第三方面，本申请提供了一种负极材料，其包括上述实施例的硅碳复合材料或根据上述实施例的硅碳复合材料的制备方法制得的硅碳复合材料。
第四方面，本申请提供了一种负极极片，其包括上述实施例的负极材料。
第五方面，本申请提供了一种电极组件，其包括上述实施例的负极极片。
第六方面，本申请提供了一种电池单体，其包括上述实施例的电极组件。
第七方面，本申请提供了一种电池，其包括上述实施例的电池单体。
第八方面，本申请提供了一种用电装置，其包括上述实施例的电池，电池用于提供电能。
第九方面，本申请提供了一种碳基体，碳基体内部具有交联型孔结构。碳基体的柔性度C2值满足0.8≤C2≤2，柔性度通过以下方法测得：对碳基体施加压力2t，保压10s，卸压100s， 反复保压和卸压20次后，分别记录第1次保压时的压实密度P5、第20次保压时的压实密度P6、第1次卸压时的压实密度P7和第20次卸压时的压实密度P8，计算C2＝N2/M2＝(P8-P7)/(P6-P5)。可选地，1.2≤C2≤1.8。
本申请实施例的技术方案中，本申请的C2为碳基体的反弹形变量对压缩形变量的倍数，用于表示碳基体的柔性度。当C2值满足0.8≤C2≤2时，碳基体具有较好的柔性度。
在一些实施例中，定义M2为P6-P5，N2为P8-P7，0.04≤M2≤0.18，0.04≤N2≤0.08。本申请的M2为碳基体第1次和第20次卸压后的压实密度变化量，用于表示硅碳复合材料多次卸压后的形变程度，且当0.05≤M2≤0.18时，碳基体的抗压性能较优。N2为碳基体第1次和第20次施压时压实密度变化量，用于表示硅碳复合材料多次受压力发生的形变程度，且当0.08≤N2≤0.2时，有利于使得C2值满足0.8≤C2≤2，进而使碳基体具有较好的柔性度。
在一些实施例中，碳基体沿由中心向表面延伸的方向依次包括第一区域和第二区域，第二区域的体积为第一区域体积的2倍，第一区域中含有2～1000nm孔径的孔的数量与第二区域中含有2～1000nm孔径的孔的数量的比值＞1。可选地，第一区域中含有2～500nm孔径的孔的数量与第二区域中含有2～500nm孔径的孔的数量的比值＞1。可选地，第一区域中含有2～200nm孔径的孔的数量与第二区域中含有2～200nm孔径的孔的数量的比值＞1。位于碳基体靠近中心位置的第一区域的2nm～1000nm的孔越多，可以内靠近中心位置的孔中沉积更多的硅材料，碳基体的柔性度越高，即碳基体的C2值越大；当第一区域中含有2nm～1000nm孔径的孔的数量与第二区域中含有2nm～1000nm孔径的孔的数量的比值＞1时，可以使得C2值满足0.8≤C2≤2。
上述说明仅是本申请技术方案的概述，为了能够更清楚了解本申请的技术手段，而可依照说明书的内容予以实施，并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的具体实施方式。
附图说明
通过阅读对下文优选实施方式的详细描述，各种其他的优点和益处对于本领域普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的，而并不认为是对本申请的限制。而且在全部附图中，用相同的附图标号表示相同的部件。在附图中：
图1为本申请一些实施例的车辆的结构示意图；
图2为本申请一些实施例的电池的分解结构示意图；
图3为本申请一些实施例的电池单体的分解结构示意图；
图4为本申请一些实施例的碳基体颗粒的结构示意图；
图5为本申请实施例1的碳基体表面在扫描倍数为Mag＝1.00KX下的扫描电镜图；
图6为本申请实施例1的碳基体表面在扫描倍数为Mag＝5.00KX下的扫描电镜图；
图7为本申请实施例1的碳基体截面在扫描倍数为Mag＝1.00KX下的扫描电镜图；
图8为本申请实施例1的碳基体截面在扫描倍数为Mag＝5.00KX下的扫描电镜图；
图9为本申请对比例1的碳基体表面在扫描倍数为Mag＝1.00KX下的扫描电镜图；
图10为本申请对比例1的碳基体表面在扫描倍数为Mag＝5.00KX下的扫描电镜图；
图11为本申请对比例1的碳基体截面在扫描倍数为Mag＝1.00KX下的扫描电镜图；
图12为本申请对比例1的碳基体截面在扫描倍数为Mag＝5.00KX下的扫描电镜图。
具体实施方式中的附图标号如下：
1000-车辆；
100-电池；200-控制器；300-马达；
10-箱体；11-第一部分；12-第二部分；
20-电池单体；21-端盖；22-壳体；23-电极组件；
400-碳基体颗粒；410-第一区域；420-第二区域。
具体实施方式
下面将结合附图对本申请技术方案的实施例进行详细的描述。以下实施例仅用于更加清楚地说明本申请的技术方案，因此只作为示例，而不能以此来限制本申请的保护范围。
除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同；本文中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请；本申请的说明书和权利要求书及上述附图说明中的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。
在本申请实施例的描述中，技术术语“第一”“第二”等仅用于区别不同对象，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量、特定顺序或主次关系。在本申请实施例的描述中，“多个”的含义是两个以上，除非另有明确具体的限定。
在本文中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员显式地和隐式地理解的是，本文所描述的实施例可以与其它实施例相结合。
在本申请实施例的描述中，术语“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本申请实施例的描述中，术语“多个”指的是两个以上(包括两个)，同理，“多组”指的是两组以上(包括两组)，“多片”指的是两片以上(包括两片)。
在本申请实施例的描述中，技术术语“中心”“纵向”“横向”“长度”“宽度”“厚度”“上”“下”“前”“后”“左”“右”“竖直”“水平”“顶”“底”“内”“外”“顺时针”“逆时针”“轴向”“径向”“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请实施例和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请实施例的限制。
在本申请实施例的描述中，除非另有明确的规定和限定，技术术语“安装”“相连”“连接”“固定”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；也可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请实施例中的具体含义。
目前，从市场形势的发展来看，动力电池的应用越加广泛。动力电池不仅被应用于水力、火力、风力和太阳能电站等储能电源***，而且还被广泛应用于电动自行车、电动摩托车、电动汽车等电动交通工具，以及军事装备和航空航天等多个领域。随着动力电池应用领域的不断扩大，其市场的需求量也在不断地扩增。
本发明人注意到，硅负极材料的能量密度较高，可达到4200mAh/g，且硅负极材料还具有嵌锂电位低及来源广泛等优势，有望成为下一代负极材料。然而，硅负极材料在实际充放电时存在剧烈的体积膨胀，一定次数循环后极片发生粉化和剥落，电池性能因此发生跳水。
为了缓解硅负极材料的膨胀问题，申请人研究发现，可以从两个方面进行改进，一方面是实现硅的纳米化，纳米硅颗粒具有更小的应力应变，但是纳米硅颗粒存在制备、分散和表面活性高等方面的问题，加工难度大；另一方面是与碳基体复合，如采用石墨、硬炭、石墨烯或碳纳米管等对硅进行隔离、包覆或者为活性硅预留膨胀空间，硅通过复合碳基体加强结构稳定性，常见的复合 方法包括液相包覆(沥青、树脂等)和气相包覆(乙炔及各类烷烃)，形成的碳层均属于刚性碳结构，该类结构承受应力超出阈值时易发生破裂，在收缩过程中又不具备弹性而坍塌，应力范围极为有限。
基于以上考虑，为了缓解硅负极材料的膨胀并增加硅负极材料的收缩性，发明人经过深入研究，设计了一种硅碳复合材料，硅材料至少部分分布于具有交联型孔结构的碳基体中，C1为硅碳复合材料的反弹形变量对压缩形变量的倍数，用于表示硅碳复合材料的柔性度。当C1值满足0.4≤C1≤2时，硅碳复合材料具有较好的柔性度，一方面可以减少硅碳复合材料整体受硅膨胀应力的影响，另一方面碳基体框架具有一定的收缩性，可进一步容纳和释放残余应力，从而维护硅碳复合材料整体的稳定性。
本申请的实施例所提到的电池是指包括一个或多个电池单体以提供更高的电压和容量的单一的物理模块。电池一般包括用于封装一个或多个电池单体的电池箱体，电池箱体可以避免液体或其他异物影响电池单体的充电或放电。
电池单体可以包括锂离子二次电池单体、锂离子一次电池单体、锂硫电池单体、钠锂离子电池单体、钠离子电池单体或镁离子电池单体等，本申请实施例对此并不限定。电池单体可呈圆柱体、扁平体、长方体或其它形状等，本申请实施例对此也不限定。电池单体一般按封装的方式分成三种：圆柱电池单体、方形电池单体和软包电池单体。
电池单体包括电极组件和电解液，电极组件由正极极片、负极极片和隔离膜组成。电池单体主要依靠金属离子在正极极片和负极极片之间移动来工作。正极极片包括正极集流体和正极活性物质层，正极活性物质层涂覆于正极集流体的表面，未涂覆正极活性物质层的正极集流体凸出于已涂覆正极活性物质层的正极集流体，未涂覆正极活性物质层的正极集流体作为正极极耳。以锂离子电池为例，正极集流体的材料可以为铝，正极活性物质可以为钴酸锂、磷酸铁锂、三元锂或锰酸锂等。负极极片包括负极集流体和负极活性物质层，负极活性物质层涂覆于负极集流体的表面，未涂覆负极活性物质层的负极集流体凸出于已涂覆负极活性物质层的负极集流体，未涂覆负极活性物质层的负极集流体作负极极耳。负极集流体的材料可以为铜，负极活性物质可以为碳或硅等。为了保证通过大电流而不发生熔断，正极极耳的数量为多个且层叠在一起，负极极耳的数量为多个且层叠在一起。隔离膜的材质可以为聚丙烯(Polypropylene，PP)或聚乙烯(Polyethylene，PE)等。此外，电极组件可以是卷绕式结构，也可以是叠片式结构，本申请实施例并不限于此。
电池单体还包括集流构件，集流构件用于将电池单体的极耳和电极端子电连接，以将电能从电极组件输送至电极端子，经电极端子输送至电池单体的外部；多个电池单体之间通过汇流部件实现电连接，以实现多个电池单体的串联、并联或者混联。
电池还包括采样端子和电池管理***，采样端子连接于汇流部件，用于采集电池单体的信息，例如电压或者温度等等。采样端子将所采集到的电池单体的信息传递至电池管理***，电池管理***检测到电池单体的信息超出正常范围时，会限制电池的输出功率以实现安全防护。
可以理解的是，本申请实施例中描述的使用电池所适用的用电装置可以为多种形式，例如，手机、便携式设备、笔记本电脑、电瓶车、电动汽车、轮船、航天器、电动玩具和电动工具等等，例如，航天器包括飞机、火箭、航天飞机和宇宙飞船等等，电动玩具包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等，电动工具包括金属切削电动工具、研磨电动工具、装配电动工具和铁道用电动工具，例如，电钻、电动砂轮机、电动扳手、电动螺丝刀、电锤、冲击电钻、混凝土振动器和电刨。
本申请的实施例描述的电池单体以及电池不仅仅局限适用于上述所描述的用电装置，还可以适用于所有使用电池单体以及电池的用电装置，但为描述简洁，下述实施例均以电动汽车为例进行说明。
请参阅图1，图1为本申请一些实施例提供的车辆的结构示意图。车辆1000可以为燃油汽车、燃气汽车或新能源汽车，新能源汽车可以是纯电动汽车、混合动力汽车或增程式汽车等。车辆1000的内部设置有电池100，电池100可以设置在车辆1000的底部或头部或尾部。电池100可以用于车辆1000的供电，例如，电池100可以作为车辆1000的操作电源。车辆1000还可以包括 控制器200和马达300，控制器200用来控制电池100为马达300供电，例如，用于车辆1000的启动、导航和行驶时的工作用电需求。
在本申请一些实施例中，电池100不仅仅可以作为车辆1000的操作电源，还可以作为车辆1000的驱动电源，代替或部分地代替燃油或天然气为车辆1000提供驱动动力。
请参照图2，图2为本申请一些实施例提供的电池的***图。电池100包括箱体10和电池单体20，电池单体20容纳于箱体10内。其中，箱体10用于为电池单体20提供容纳空间，箱体10可以采用多种结构。在一些实施例中，箱体10可以包括第一部分11和第二部分12，第一部分11与第二部分12相互盖合，第一部分11和第二部分12共同限定出用于容纳电池单体20的容纳空间。第二部分12可以为一端开口的空心结构，第一部分11可以为板状结构，第一部分11盖合于第二部分12的开口侧，以使第一部分11与第二部分12共同限定出容纳空间；第一部分11和第二部分12也可以是均为一侧开口的空心结构，第一部分11的开口侧盖合于第二部分12的开口侧。当然，第一部分11和第二部分12形成的箱体10可以是多种形状，比如，圆柱体、长方体等。
在电池100中，电池单体20可以是多个，多个电池单体20之间可串联或并联或混联，混联是指多个电池单体20中既有串联又有并联。多个电池单体20之间可直接串联或并联或混联在一起，再将多个电池单体20构成的整体容纳于箱体10内；当然，电池100也可以是多个电池单体20先串联或并联或混联组成电池模块形式，多个电池模块再串联或并联或混联形成一个整体，并容纳于箱体10内。电池100还可以包括其他结构，例如，该电池100还可以包括汇流部件，用于实现多个电池单体20之间的电连接。
其中，每个电池单体20可以为二次电池或一次电池；还可以是锂硫电池、钠离子电池或镁离子电池，但不局限于此。电池单体20可呈圆柱体、扁平体、长方体或其它形状等。
请参照图3，图3为本申请一些实施例提供的电池单体的分解结构示意图。电池单体20是指组成电池的最小单元。如图3，电池单体20包括有端盖21、壳体22、电极组件23以及其他的功能性部件。
端盖21是指盖合于壳体22的开口处以将电池单体20的内部环境隔绝于外部环境的部件。不限地，端盖21的形状可以与壳体22的形状相适应以配合壳体22。可选地，端盖21可以由具有一定硬度和强度的材质(如铝合金)制成，这样，端盖21在受挤压碰撞时就不易发生形变，使电池单体20能够具备更高的结构强度，安全性能也可以有所提高。端盖21上可以设置有如电极端子等的功能性部件。电极端子可以用于与电极组件23电连接，以用于输出或输入电池单体20的电能。在一些实施例中，端盖21上还可以设置有用于在电池单体20的内部压力或温度达到阈值时泄放内部压力的泄压机构。端盖21的材质也可以是多种的，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。在一些实施例中，在端盖21的内侧还可以设置有绝缘件，绝缘件可以用于隔离壳体22内的电连接部件与端盖21，以降低短路的风险。示例性的，绝缘件可以是塑料、橡胶等。
壳体22是用于配合端盖21以形成电池单体20的内部环境的组件，其中，形成的内部环境可以用于容纳电极组件23、电解液以及其他部件。壳体22和端盖21可以是独立的部件，可以于壳体22上设置开口，通过在开口处使端盖21盖合开口以形成电池单体20的内部环境。不限地，也可以使端盖21和壳体22一体化，具体地，端盖21和壳体22可以在其他部件入壳前先形成一个共同的连接面，当需要封装壳体22的内部时，再使端盖21盖合壳体22。壳体22可以是多种形状和多种尺寸的，例如长方体形、圆柱体形、六棱柱形等。具体地，壳体22的形状可以根据电极组件23的具体形状和尺寸大小来确定。壳体22的材质可以是多种，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。
电极组件23是电池单体20中发生电化学反应的部件。壳体22内可以包含一个或更多个电极组件23。电极组件23主要由正极片和负极片卷绕或层叠放置形成，并且通常在正极片与负极片之间设有隔膜。正极片和负极片具有活性物质的部分构成电极组件的主体部，正极片和负极片不具有活性物质的部分各自构成极耳。正极极耳和负极极耳可以共同位于主体部的一端或是分别位于主体部的两端。在电池的充放电过程中，正极活性物质和负极活性物质与电解液发生反应，极耳连接电极端子以形成电流回路。
根据本申请的一些实施例，本申请提供了一种硅碳复合材料，包括：碳基体和硅材料，碳基体内部具有交联型孔结构，硅材料至少部分分布于交联型孔结构中。硅碳复合材料的柔性度C1值满足0.4≤C1≤2，柔性度通过以下方法测得：对硅碳复合材料施加压力2t，保压10s，卸压100s，反复保压和卸压20次后，分别记录第1次保压时的压实密度P1、第20次保压时的压实密度P2、第1次卸压时的压实密度P3和第20次卸压时的压实密度P4，计算C1＝N1/M1＝(P4-P3)/(P2-P1)。
碳基体为用于负载硅材料的载体，其具有多孔结构。
硅材料为能够提供硅原子的单质或化合物。
交联型孔结构是指碳基体内部的孔之间相互连通形成的交联型结构。
作为示例，C1值可以为0.4、0.5、0.6、0.7、0.8、0.9、1.0、1.1、1.2、1.3、1.4、1.5、1.6、1.7、1.8、1.9或2.0。
压实密度的计算公式如下：
P＝m/V＝m/(S*H)；
P为粉末的压实密度，单位为g/m；m为试样质量，单位为g；S为模具底面积，单位为cm2；H为压实高度，单位是cm。
可选地，P1、P2、P3、P4均满足1g/cm3≤Px≤2.0g/cm3，x＝1、2、3或4。
可选地，1g/cm3≤Px≤1.5g/cm3。
需要说明的是，本申请检测柔性度的检测方法的依据为GB/T 24533-2009。测试流程为在外力压缩过程中，随着粉末移动和变形，空隙被填充，颗粒间接触面积增大，使原子间产生吸引力且颗粒间的机械契合作用增强，从而形成具有一定密度的压坯。
硅材料至少部分分布于具有交联型孔结构的碳基体中，本申请的C1为硅碳复合材料的反弹形变量对压缩形变量的倍数，用于表示硅碳复合材料的柔性度。当C1值满足0.4≤C1≤2时，硅碳复合材料具有较好的柔性度，一方面可以减少硅碳复合材料整体受硅膨胀应力的影响，另一方面碳基体框架具有一定的收缩性，可进一步容纳和释放残余应力，从而维护硅碳复合材料整体的稳定性。
根据本申请的一些实施例，可选地，0.8≤C1≤2。
当C1值满足0.8≤C1≤2时，硅碳复合材料具有较好的柔性度，一方面可以减少硅碳复合材料整体受硅膨胀应力的影响，另一方面碳基体框架具有一定的收缩性，可进一步容纳和释放残余应力，从而维护硅碳复合材料整体的稳定性。
根据本申请的一些实施例，可选地，定义P2-P1为M1，P4-P3＝N1，0.05≤M1≤0.18，0.08≤N1≤0.2。
作为示例，M1值可以为0.05、0.06、0.07、0.08、0.09、0.1、0.11、0.12、0.13、0.14、0.15、0.16、0.17或0.18。
作为示例，N1值可以为0.08、0.09、0.1、0.11、0.12、0.13、0.14、0.15、0.16、0.17、0.18、0.19或0.2。
本申请的M1为硅碳复合材料第1次和第20次卸压后的压实密度变化量，用于表示硅碳复合材料多次卸压后的形变程度，且当0.05≤M1≤0.18时，硅碳复合材料的抗压性能较优。N1为硅碳复合材料第1次和第20次施压时压实密度变化量，用于表示硅碳复合材料多次受压力发生的形变程度，且当0.04≤N1≤0.2时，有利于使得C1值满足0.8≤C1≤2，进而使硅碳复合材料具有较好的柔性度。
可选地，0.08≤M1≤0.15，0.10≤N1≤0.18。
根据本申请的一些实施例，可选地，请参阅图4，图4为本申请一些实施例的碳基体颗粒 的结构示意图。碳基体沿由中心向表面延伸的方向依次包括第一区域和第二区域，且碳基体由第一区域和第二区域组成，第二区域的体积为第一区域体积的2倍，第一区域中含有2nm～1000nm孔径的孔的数量与第二区域中含有2nm～1000nm孔径的孔的数量的比值＞1。
第一区域为碳基体中部的区域，第二区域为碳基体中包覆第一区域的区域，且第一区域和第二区域可通过计算并划分，例如将碳基体颗粒近似为球形，通过碳基体颗粒的半径计算出两个相同的体积，并划分为第一区域和第二区域。
位于碳基体靠近中心位置的第一区域的2nm～1000nm的孔越多，可以内靠近中心位置的孔中沉积更多的硅材料，硅碳复合材料的柔性度越高，即硅碳复合材料的C1值越大；当第一区域中含有2nm～1000nm孔径的孔的数量与第二区域中含有2nm～1000nm孔径的孔的数量的比值＞1时，可以使得C1值满足0.4≤C1≤2。
可选地，第一区域中含有2nm～500nm孔径的孔的数量与第二区域中含有2nm～500nm孔径的孔的数量的比值＞1。
可选地，第一区域中含有2nm～200nm孔径的孔的数量与第二区域中含有2nm～200nm孔径的孔的数量的比值＞1。
可选地，请参阅图4，碳基体颗粒400为球形或类球形，将碳基体颗粒400沿中心向表面延伸的方向按照距离划分成10等分，从而得到10个区域，10个区域中最内的区域为包括中心的区域，从最内的第1个区域到第7个区域即为第一区域410，最外侧的三个区域(第8个区域到第10个区域)为第二区域420。
根据本申请的一些实施例，可选地，硅碳复合材料的比表面积SSA值满足1g/cm2≤SSA≤10g/cm2。
作为示例，硅碳复合材料的比表面积SSA值可以为1g/cm2、2g/cm2、3g/cm2、4g/cm2、5g/cm2、6g/cm2、7g/cm2、8g/cm2、9g/cm2或10g/cm2。
当硅碳复合材料的比表面积SSA值满足1g/cm2≤SSA≤10g/cm2时，硅碳复合材料的表面缺陷少，有利于形成稳定的SEI膜，减少不可逆锂离子损失。
可选地，硅碳复合材料的比表面积SSA值满足3g/cm2≤SSA≤7g/cm2。
根据本申请的一些实施例，可选地，硅碳复合材料的Dv10≤5μm，Dv50≤8μm，Dv90≤20μm，且(Dv90-Dv10)/Dv50≥1.6。
作为示例，硅碳复合材料的Dv10值可以为0.1μm、0.5μm、1μm、2μm、3μm、4μm或5μm。
作为示例，硅碳复合材料的Dv50值可以为1μm、2μm、3μm、4μm、5μm、6μm、7μm或8μm。
作为示例，硅碳复合材料的Dv90值可以为1μm、2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm、10μm、11μm、12μm、13μm、14μm、15μm、16μm、17μm、18μm、19μm或20μm。
有利于提高硅碳复合材料应用时的压实密度，提高活性物颗粒的电接触，从而提高负极极片的导电率。根据本申请的一些实施例，可选地，硅碳复合材料5t下的粉体压实密度PD≤1.1g/cm3。
作为示例，硅碳复合材料5t下的粉体压实密度PD值可以为0.1g/cm3、0.2g/cm3、0.3g/cm3、0.4g/cm3、0.5g/cm3、0.6g/cm3、0.7g/cm3、0.8g/cm3、0.9g/cm3、1g/cm3或1.1g/cm3。
5t下的粉体压实密度PD≤1.1g/cm3的硅碳复合材料具有多孔结构。根据本申请的一些实施例，可选地，硅材料包括硅氧化合物、硅单质和合金硅中的任意一种或多种。
硅材料具有能量密度高、嵌锂电位低及来源广泛等优点，硅氧化合物、硅单质和合金硅能够负载于碳基体的孔中制得硅碳复合材料，用于制成负极材料和能量密度高的电池。
根据本申请的一些实施例，本申请还提供一种上述实施例的硅碳复合材料的制备方法，其包括：将原料经过第一热处理制得固态树脂，将粉碎后的固态树脂经过第二热处理使中性溶剂挥发，制得碳前驱体，将碳前驱体经过热解碳化处理，制得碳基体，将硅材料复合在碳基体的交联型孔结构中。原料包括树脂、致孔剂和中性溶剂。
原料为树脂和致孔剂分散于中性溶剂中制得。
固态树脂为呈现为固态且包括树脂、致孔剂和中性溶剂的物质。
粉碎后的固态树脂通过固态树脂依次经过粗破、细破和磨粉步骤制得，使最终制得的碳基体的Dv10≤5μm，Dv50≤8μm，Dv90≤20μm，且(Dv90-Dv10)/Dv50≥1.6。
其中，粗破包括使用对辊及旋风磨对块体材料进行粗破，实现块体物料变为平均直径为1cm左右的小块体。
细破包括使用石盘机械磨进行细破，第一阶段以700～1000r/min破碎，第二阶段以转速2000～2500r/min加快细破，进行收料；后续重复第二阶段破碎过程2～3次，得到细料，颗粒粒径小于0.15mm。
磨粉包括通过气流磨进行磨粉，将腔体内部空气排尽，调节气压阀至最大值(一般为0.5Mpa)，随后调节进气压力、粉碎压力及进料压力分别为0.36Mpa、0.36Mpa、和0.34Mpa。进一步将目标样品吸入磨料腔进行破碎，5min后关闭气体阀门和震动开关，收集磨好的样品。
将包括树脂、致孔剂和中性溶剂的原料经第一热处理能够形成固态树脂，有利于后续加工。再将粉碎后的固态树脂经第二热处理使溶剂挥发使得孔相互连通形成交联型孔结构，制得碳前驱体。将碳前驱体经过热解碳化处理使得有机物碳化制得碳基体。本申请的硅碳复合材料的制备方法通过原位致孔的方法，所得碳基体内部和表面均分布有交联型孔结构，且孔的孔径合适，有利于硅材料在碳基体的孔中填充和分散，从而制得结构更为稳定的硅碳复合材料。
可选地，在将原料经过第一热处理前，先将原料转移到模具中静置。
可选地，在将硅材料复合在碳基体的交联型孔结构中前，需要通过除杂、除磁和分级的步骤得到符合粒径要求的碳基体。
具体包括先向酸洗釜内注入2吨软化水，投入需要酸洗的目标物料1000kg，选择模式去除表层浮碳，排出黑水；重复以上步骤直到排出的软化水澄清后，加入3～5wt％左右的盐酸。投入量参考物料初始pH值并设置分段投入分量；蒸汽蒸煮0.5h以上，加净化水并溢出部分黑水；开启离心，低转速运行；随后打开出料阀，将水和物料通入离心脱水腔，脱水10min；离心机加到中速运行，布水管喷入反渗透水进行漂洗20min，转至高速离心脱水20min；物料倒出后，转移至干燥炉进一步脱水烘干至水含量小于5wt％。在酸洗过程中溢出除去细粉及金属杂质，完成除铁除磁，进一步再将干料通过旋振筛，进行筛分和粉料收集。
可选地，将硅材料复合在碳基体的交联型孔结构中的方法包括化学气相沉积法。
根据本申请的一些实施例，可选地，第二热处理的处理温度为150～400℃，处理时间为至少10h。
作为示例，第二热处理的处理温度可以为150℃、180℃、200℃、220℃、250℃、280℃、300℃、330℃、350℃、370℃或400℃。
作为示例，第二热处理的处理时间可以为10h、12h、14h、16h、18h或20h。
选择合适的第二热处理的处理温度和处理时间有利于使溶剂挥发使得孔相互连通形成交联型孔结构，如果温度太高，会使得制得的硅碳复合材料的孔变大，硅碳复合材料变脆，硅碳复合材料C1值变小。
根据本申请的一些实施例，可选地，树脂和中性溶剂的质量比为1:10～10:1，树脂和致孔剂的质量比为1:5～10:1。
作为示例，树脂和中性溶剂的质量比可以为1:10、1:9、1:8、1:7、1:6、1:5、1:4、1:3、 1:2、1:1、2:1、3:1、4:1、5:1、6:1、7:1、8:1、9:1或10:1。
作为示例，树脂和致孔剂的质量比可以为1:5、1:4、1:3、1:2、1:1、2:1、3:1、4:1、5:1、6:1、7:1、8:1、9:1或10:1。
选择合适的树脂和中性溶剂的配比有利于控制制得的硅碳复合材料中的孔的数量和大小。
可选地，树脂包括酚醛树脂、环氧树脂和聚氨酯中的任意一种或多种。
可选地，中性溶剂包括甲醇、乙醇、乙二醇、聚乙二醇、丙三醇和异丙醇中的任意一种或多种。
可选地，致孔剂包括氯化钾、氯化钠、氯化锌、氢氧化钠、氢氧化钾、碳酸钠、碳酸钾、碳酸氢钠、磷酸、醋酸钠、醋酸锌、醋酸镍和醋酸铵中的任意一种或多种。
根据本申请的一些实施例，可选地，第一热处理包括在60～150℃下静置至少10h。
作为示例，第一热处理的处理温度可以为60℃、70℃、80℃、90℃、100℃、110℃、120℃、130℃、140℃或150℃。
作为示例，第一热处理的处理时间可以为10h、12h、14h、16h、18h或20h。
选择合适的第一热处理的处理温度和处理时间有利于获得固态树脂。
根据本申请的一些实施例，可选地，热解碳化处理包括在600～1600℃下烧结1～3h。
作为示例，热解碳化处理的处理温度可以为600℃、650℃、700℃、750℃、800℃、850℃、900℃、950℃、1000℃、1050℃、1100℃、1150℃、1200℃、1250℃、1300℃、1350℃、1400℃、1450℃或1500℃。
作为示例，热解碳化处理的处理时间可以为1h、1.5h、2h、2.5h或3h。
选择合适的热解碳化处理的温度有利于获得内部和表面均分布有交联型孔结构的碳基体。
可选地，热解碳化处理的温度为800～1000℃。
根据本申请的一些实施例，可选地，本申请还提供一种碳基体，碳基体内部具有交联型孔结构。碳基体的柔性度C2值满足0.8≤C2≤2，柔性度通过以下方法测得：对碳基体施加压力2t，保压10s，卸压100s，反复保压和卸压20次后，分别记录第1次保压时的压实密度P5、第20次保压时的压实密度P6、第1次卸压时的压实密度P7和第20次卸压时的压实密度P8，计算C2＝N2/M2＝(P8-P7)/(P6-P5)。可选地，1.2≤C2≤1.8。
作为示例，C2值可以为0.8、0.9、1.0、1.1、1.2、1.3、1.4、1.5、1.6、1.7、1.8、1.9或2.0。
本申请的C2为碳基体的反弹形变量对压缩形变量的倍数，用于表示碳基体的柔性度。当C2值满足0.8≤C2≤2时，碳基体具有较好的柔性度。
根据本申请的一些实施例，可选地，定义M2为P6-P5，N2为P8-P7，0.04≤M2≤0.18，0.04≤N2≤0.08。
作为示例，M2值可以为0.04、0.05、0.06、0.07、0.08、0.09、0.1、0.11、0.12、0.13、0.14、0.15、0.16、0.17或0.18。
作为示例，N2值可以为0.04、0.05、0.06、0.07或0.08。
本申请的M2为碳基体第1次和第20次卸压后的压实密度变化量，用于表示硅碳复合材料多次卸压后的形变程度，且当0.05≤M2≤0.18时，碳基体的抗压性能较优。N2为碳基体第1次和第20次施压时压实密度变化量，用于表示硅碳复合材料多次受压力发生的形变程度，且当0.08≤N2≤0.2时，有利于使得C2值满足0.8≤C2≤2，进而使碳基体具有较好的柔性度。
根据本申请的一些实施例，可选地，碳基体沿由中心向表面延伸的方向依次包括第一区域 和第二区域，第二区域的体积为第一区域体积的2倍，第一区域中含有2～1000nm孔径的孔的数量与第二区域中含有2～1000nm孔径的孔的数量的比值＞1。
位于碳基体靠近中心位置的第一区域的2nm～1000nm的孔越多，可以内靠近中心位置的孔中沉积更多的硅材料，碳基体的柔性度越高，即碳基体的C2值越大；当第一区域中含有2nm～1000nm孔径的孔的数量与第二区域中含有2nm～1000nm孔径的孔的数量的比值＞1时，可以使得C2值满足0.8≤C2≤2。
需要说明的是，第一区域中含有2～1000nm孔径的孔的数量，以及第二区域中含有2～1000nm孔径的孔的数量可以根据碳基体截面的扫描电镜图观察得到。
可选地，第一区域中含有2～500nm孔径的孔的数量与第二区域中含有2～500nm孔径的孔的数量的比值＞1。
可选地，第一区域中含有2～200nm孔径的孔的数量与第二区域中含有2～200nm孔径的孔的数量的比值＞1。
以下结合实施例对本申请的硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池和碳基体作进一步的详细描述。
实施例1
本申请实施例提供一种硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池和碳基体。
S1、制备碳基体
将50g固含量为80％的酚醛树脂和25g无水乙醇，混合搅拌得到第一混合液，再向第一混合液中加入40g氯化锌，在1000r/min转速下搅拌3h制得原料。
将原料转移到受热模具中，再将受热模具置于鼓风烘箱中经过第一热处理制得固态树脂，第一热处理的温度为80℃，时间为10h；再将固态树脂依次经过粗破、细破和磨粉后制得粉碎后的固态树脂，将粉碎后的固态树脂经第二热处理使中性溶剂挥发制得碳前驱体，第二热处理的温度为180℃，时间为10h；将碳前驱体经热解碳化处理制得碳基体，热解碳化处理的温度为1000℃，时间为2h；再将制得的碳基体经过除杂、除磁和分级得到符合粒径要求的碳基体。
碳基体的第一区域中含有2nm～1000nm孔径的孔的数量与第二区域中含有2nm～1000nm孔径的孔的数量的比值为5.3，C2值为1.40，M2值为0.05，N2值为0.07。
S2、制备硅碳复合材料
通过化学气相沉积法将纳米硅在碳基体中均匀分散，制得硅碳复合材料。
硅碳复合材料的C1值为1.7，M1值为0.06，N1值为0.1，比表面积SSA为6g/cm2，Dv10为3.2μm，Dv50为7μm，Dv90为15μm，(Dv90-Dv10)/Dv50为1.7。
S3、制备负极极片
将负极材料(25wt％硅碳复合材料+75wt％人造石墨)、导电剂和粘接剂按比例混合成浆料，其中负极含量不少于95.5wt％，粘接剂为羧甲基纤维素钠，导电剂为导电炭黑，将浆料均匀涂覆在铜箔上，真空80℃烘干制成负极极片(水含量≤5ppm)。
S4、制备电池
将制得的负极电极片在手套箱内进行电池组装，金属锂片作为对电极，电解液为溶解有LiPF6的EC:DMC(体积比)＝1:1的溶剂，其中添加加有10v/v％的FEC。
将正极极片、隔离膜、负极极片按顺序叠好，经卷绕后得到电极组件，将电极组件装入外包装中，加入上述电解液，经封装、静置、化成、老化等工序后，得到二次电池。
对比例1
本申请对比例提供一种硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池和碳基体。
S1、制备碳基体
将50g固含量为80％的酚醛树脂、50g无水乙醇和5mL磷酸，混合搅拌得到第一混合液，磷酸的质量浓度为85wt％，再向第一混合液中加入80g氯化锌，在200r/min转速下搅拌1h制得原料。
将原料在室温下(15～25℃)下静置3h后制得固态块，将固态块在80℃下脱去残留溶剂；再将固态块经过粗破、细破和磨粉后制得淡黄色的粉碎后的固态块；将粉碎后的固态块在1000℃下碳化2h，制得碳基体；再将制得的碳基体经过除杂、除磁和分级得到符合粒径要求的碳基体。
碳基体的第一区域中含有2nm～1000nm孔径的孔的数量与第二区域中含有2nm～1000nm孔径的孔的数量的比值为3，C2值为0.5，M2值为0.08，N2值为0.04。
S2、制备硅碳复合材料
通过化学气相沉积法将纳米硅在碳基体中均匀分散，制得硅碳复合材料。
硅碳复合材料的C1值为0.29，M1值为0.14，N1值为0.04，比表面积SSA为7g/cm2，Dv10为3μm，Dv50为7.8μm，Dv90为15.7μm，(Dv90-Dv10)/Dv50为1.63。
S3、制备负极极片
将负极材料(25wt％硅碳复合材料+75wt％人造石墨)、导电剂和粘接剂按比例混合成浆料，其中负极含量不少于95.5wt％，粘接剂为羧甲基纤维素钠，导电剂为导电炭黑，将浆料均匀涂覆在铜箔上，真空80℃烘干制成负极极片(水含量≤5ppm)。
S4、制备电池
将制得的负极电极片在手套箱内进行电池组装，金属锂片作为对电极，电解液为溶解有LiPF6的EC:DMC(体积比)＝1:1的溶剂，其中添加加有10v/v％的FEC。
将正极极片、隔离膜、负极极片按顺序叠好，经卷绕后得到电极组件，将电极组件装入外包装中，加入上述电解液，经封装、静置、化成、老化等工序后，得到二次电池。
实施例1～25和对比例1～3的碳基体和硅碳复合材料的参数如表1所示。
表1实施例1～25和对比例1～3的碳基体和硅碳复合材料的参数
Figure PCTCN2022108327-appb-000001
Figure PCTCN2022108327-appb-000002
表1中的比值为第一区域中含有2nm～1000nm孔径的孔的数量与第二区域中含有2nm～1000nm孔径的孔的数量的比值。
试验例1
分别取实施例1和对比例1制得的碳基体，观察其碳基体表面形貌图和截面形貌图，其中，图5为本申请实施例1的碳基体表面在扫描倍数为Mag＝1.00KX下的扫描电镜图，图6为本申请实施例1的碳基体表面在扫描倍数为Mag＝5.00KX下的扫描电镜图，图7为本申请实施例1的碳基体截面在扫描倍数为Mag＝1.00KX下的扫描电镜图，图8为本申请实施例1的碳基体截面在扫描倍数为Mag＝5.00KX下的扫描电镜图，图9为本申请对比例1的碳基体表面在扫描倍数为Mag＝1.00KX下的扫描电镜图，图10为本申请对比例1的碳基体表面在扫描倍数为Mag＝5.00KX下的扫描电镜图，图11为本申请对比例1的碳基体截面在扫描倍数为Mag＝1.00KX下的扫描电镜图，图12为本申请对比例1的碳基体截面在扫描倍数为Mag＝5.00KX下的扫描电镜图。
由图5～8可知，实施例1制得的碳基体表面和内部均见明显空隙，而由图9～12可知，对比例1制得的碳基体表面和内部未见明显空隙。
试验例2
分别检测实施例1～25和对比例1～3制得的电池的循环次数，将制备好的扣式电池置于测试柜中对应通道上，恒温25℃条件下进行测试，测试结果如表2所示。
具体测试过程：
在测试柜中对应通道上先将扣式电池静置12h，以0.5C倍率放电到2.5V；静置5min后，以0.5C进行恒流充电至4.25V；静置5min后，再次重复步骤上述步骤至电池的放电衰减容量为第一次放电容量的80％。
表2实施例1～25和对比例1～3制得的电池的循环次数
项目 循环次数
实施例1 1350
实施例2 1220
实施例3 1256
实施例4 1300
实施例5 1320
实施例6 1324
实施例7 1345
实施例8 1360
实施例9 1250
实施例10 1325
实施例11 1350
实施例12 1335
实施例13 1322
实施例14 1345
实施例15 1278
实施例16 1390
实施例17 1378
实施例18 1280
实施例19 1240
实施例20 1235
实施例21 1270
实施例22 1210
实施例23 1202
实施例24 920
实施例25 880
对比例1 950
对比例2 856
对比例3 900
由实施例1～25和对比例1～3对比可知，当硅碳复合材料的C1值越大，电池的循环寿命越高，当硅碳复合材料的C1值＜0.4时，电池的循环寿命仅为856～950；当硅碳复合材料的C1值满足0.4≤C1≤2时，电池的循环寿命为1200～1360次；且当硅碳复合材料的C1值为2时，电池的循环寿命达到1360次。
由实施例1～25对比可知，当碳基体的C1值超过2，或小于0.8时，制得的硅碳复合材料的C1值＜0.5，从而导致电池的循环寿命偏低。
最后应说明的是：以上各实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述各实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围，其均应涵盖在本申请的权利要求和说明书的范围当中。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (22)

  1. 一种硅碳复合材料，其中，所述硅碳复合材料包括碳基体和硅材料，所述碳基体内部具有交联型孔结构，所述硅材料至少部分分布于所述交联型孔结构中；
    所述硅碳复合材料的柔性度C1值满足0.4≤C1≤2，所述柔性度通过以下方法测得：
    对所述硅碳复合材料施加压力2t，保压10s，卸压100s，反复保压和卸压20次后，分别记录第1次保压时的压实密度P1、第20次保压时的压实密度P2、第1次卸压时的压实密度P3和第20次卸压时的压实密度P4，计算C1＝(P4-P3)/(P2-P1)。
  2. 根据权利要求1所述的硅碳复合材料，其中，0.8≤C1≤2。
  3. 根据权利要求1或2所述的硅碳复合材料，其中，定义P2-P1为M1，P4-P3＝N1，0.05≤M1≤0.18，0.08≤N1≤0.2；
    可选地，0.08≤M1≤0.15，0.10≤N1≤0.18。
  4. 根据权利要求1～3任一项所述的硅碳复合材料，其中，所述碳基体沿由中心向表面延伸的方向依次包括第一区域和第二区域，且所述碳基体由所述第一区域和所述第二区域组成，所述第二区域的体积为所述第一区域体积的2倍，所述第一区域中含有2nm～1000nm孔径的孔的数量与所述第二区域中含有2nm～1000nm孔径的孔的数量的比值＞1；
    可选地，所述第一区域中含有2nm～500nm孔径的孔的数量与所述第二区域中含有2nm～500nm孔径的孔的数量的比值＞1；
    可选地，所述第一区域中含有2nm～200nm孔径的孔的数量与所述第二区域中含有2nm～200nm孔径的孔的数量的比值＞1。
  5. 根据权利要求1～4任一项所述的硅碳复合材料，其中，所述硅碳复合材料的比表面积SSA值满足1g/cm2≤SSA≤10g/cm2；
    可选地，所述硅碳复合材料的比表面积SSA值满足3g/cm2≤SSA≤7g/cm2。
  6. 根据权利要求1～5任一项所述的硅碳复合材料，其中，所述硅碳复合材料的Dv10≤5μm，Dv50≤8μm，Dv90≤20μm，且(Dv90-Dv10)/Dv50≥1.6。
  7. 根据权利要求1～6任一项所述的硅碳复合材料，其中，所述硅碳复合材料5t下的粉体压实密度PD≤1.1g/cm3。
  8. 根据权利要求1～7任一项所述的硅碳复合材料的制备方法，其中，所述硅材料包括硅氧化合物、硅单质和合金硅中的任意一种或多种。
  9. 一种权利要求1～8任一项所述的硅碳复合材料的制备方法，其中，所述硅碳复合材料的制备方法包括：将原料经过第一热处理制得固态树脂，将粉碎后的固态树脂经过第二热处理使中性溶剂挥发，制得碳前驱体，将所述碳前驱体经过热解碳化处理，制得所述碳基体，将所述硅材料复合在所述碳基体的所述交联型孔结构中；
    所述原料包括树脂、致孔剂和所述中性溶剂。
  10. 根据权利要求9所述的硅碳复合材料的制备方法，其中，所述第二热处理的处理温度为150～400℃，处理时间为至少10h。
  11. 根据权利要求9所述的硅碳复合材料的制备方法，其中，所述树脂和所述中性溶剂的质量比为1:10～10:1，所述树脂和所述致孔剂的质量比为1:5～10:1；
    可选地，所述树脂包括酚醛树脂、环氧树脂和聚氨酯中的任意一种或多种；
    可选地，所述中性溶剂包括甲醇、乙醇、乙二醇、聚乙二醇、丙三醇和异丙醇中的任意一种或多种；
    可选地，所述致孔剂包括氯化钾、氯化钠、氯化锌、氢氧化钠、氢氧化钾、碳酸钠、碳酸钾、碳酸氢钠、磷酸、醋酸钠、醋酸锌、醋酸镍和醋酸铵中的任意一种或多种。
  12. 根据权利要求9所述的硅碳复合材料的制备方法，其中，所述第一热处理包括在60～150℃下静置至少10h。
  13. 根据权利要求9所述的硅碳复合材料的制备方法，其中，所述热解碳化处理包括在600～1600℃下烧结1～3h；
    可选地，所述热解碳化处理的温度为800～1000℃。
  14. 一种负极材料，其中，所述负极材料包括权利要求1～7任一项所述的硅碳复合材料或根据 权利要求9～13所述的硅碳复合材料的制备方法制得的硅碳复合材料。
  15. 一种负极极片，其中，所述负极极片包括权利要求14所述的负极材料。
  16. 一种电极组件，其中，所述电极组件包括权利要求15所述的负极极片。
  17. 一种电池单体，其中，所述电池单体包括权利要求16所述的电极组件。
  18. 一种电池，其中，所述电池包括权利要求17所述的电池单体。
  19. 一种用电装置，其中，所述用电装置包括权利要求18所述的电池，所述电池用于提供电能。
  20. 一种碳基体，其中，所述碳基体内部具有交联型孔结构，所述碳基体的柔性度C2值满足0.8≤C2≤2，所述柔性度通过以下方法测得：
    对所述碳基体施加压力2t，保压10s，卸压100s，反复保压和卸压20次后，分别记录第1次保压时的压实密度P5、第20次保压时的压实密度P6、第1次卸压时的压实密度P7和第20次卸压时的压实密度P8，计算C2＝(P8-P7)/(P6-P5)；
    可选地，1.2≤C2≤1.8。
  21. 根据权利要求20所述的碳基体，其中，定义M2为P6-P5，N2为P8-P7，0.04≤M2≤0.18，0.04≤N2≤0.08。
  22. 根据权利要求20所述的碳基体，其中，所述碳基体沿由中心向表面延伸的方向依次包括第一区域和第二区域，所述第二区域的体积为所述第一区域体积的2倍，所述第一区域中含有2～1000nm孔径的孔的数量与所述第二区域中含有2～1000nm孔径的孔的数量的比值＞1；
    可选地，所述第一区域中含有2～500nm孔径的孔的数量与所述第二区域中含有2～500nm孔径的孔的数量的比值＞1；
    可选地，所述第一区域中含有2～200nm孔径的孔的数量与所述第二区域中含有2～200nm孔径的孔的数量的比值＞1。
PCT/CN2022/108327 2022-07-27 2022-07-27 硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池、用电装置和碳基体 WO2024020880A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/CN2022/108327 WO2024020880A1 (zh) 2022-07-27 2022-07-27 硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池、用电装置和碳基体

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2022/108327 WO2024020880A1 (zh) 2022-07-27 2022-07-27 硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池、用电装置和碳基体

Publications (1)

Publication Number Publication Date
WO2024020880A1 true WO2024020880A1 (zh) 2024-02-01

Family

ID=89704852

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/108327 WO2024020880A1 (zh) 2022-07-27 2022-07-27 硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池、用电装置和碳基体

Country Status (1)

Country Link
WO (1) WO2024020880A1 (zh)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012226937A (ja) * 2011-04-19 2012-11-15 Daiso Co Ltd 非水電解質二次電池
CN103682287A (zh) * 2013-12-19 2014-03-26 深圳市贝特瑞新能源材料股份有限公司 一种锂离子电池硅基复合负极材料、制备方法及电池
CN111261864A (zh) * 2020-02-10 2020-06-09 马鞍山科达普锐能源科技有限公司 一种锂离子电池用硅碳负极材料及其制备方法
CN114051663A (zh) * 2021-03-16 2022-02-15 宁德新能源科技有限公司 负极材料及其制备方法、电化学装置及电子装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012226937A (ja) * 2011-04-19 2012-11-15 Daiso Co Ltd 非水電解質二次電池
CN103682287A (zh) * 2013-12-19 2014-03-26 深圳市贝特瑞新能源材料股份有限公司 一种锂离子电池硅基复合负极材料、制备方法及电池
CN111261864A (zh) * 2020-02-10 2020-06-09 马鞍山科达普锐能源科技有限公司 一种锂离子电池用硅碳负极材料及其制备方法
CN114051663A (zh) * 2021-03-16 2022-02-15 宁德新能源科技有限公司 负极材料及其制备方法、电化学装置及电子装置

Similar Documents

Publication Publication Date Title
US9911976B2 (en) Negative electrode active material for secondary battery, conductive composition for secondary battery, negative electrode material comprising same, negative electrode structure and secondary battery comprising same, and method for manufacturing same
CN106450161B (zh) 二次电池用负极及其制备方法
JP2018512699A (ja) ケイ素：ケイ酸リチウムの複合材母材中にナノケイ素粒子を埋込んだケイ素−酸化ケイ素−リチウムの複合材料、及びその製造工程
US20120189914A1 (en) Lithium secondary battery and positive electrode for said battery
CN107634259B (zh) 一种锂二次电池用杂交电解质和锂二次电池
KR101667125B1 (ko) 비정질 탄소 입자의 제조 방법, 비정질 탄소 입자, 리튬 이온 이차 전지용 부극 재료 및 리튬 이온 이차 전지
KR101560892B1 (ko) 다공성 규소 산화물―탄소재 복합체를 포함하는 음극 활물질 및 이의 제조방법
CN107749472B (zh) 一种高性能石墨复合负极材料及其制备方法
CN110112408B (zh) 一种石墨烯-硅复合材料及其制备方法、电极材料及电池
US20230369589A1 (en) Silicon-based negative electrode material containing silicate skeleton, negative electrode plate, and lithium battery
JP3305995B2 (ja) リチウム二次電池負極用黒鉛粒子
CN115548260B (zh) 一种正极极片及其制备方法和锂离子电池
WO2024020880A1 (zh) 硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池、用电装置和碳基体
CN116454283A (zh) 一种钾离子电池正极添加剂及其制备方法与应用
JP5836254B2 (ja) 導電性複合粒子、正極活物質及びそれを用いた二次電池
KR101660159B1 (ko) 실리카겔-탄소나노섬유 복합소재를 이용한 리튬이차전지용 음극재 및 그 제조방법
CN112824320B (zh) 一种电极材料及其制备方法及电池
CN118044026A (zh) 硅碳复合材料及其制备方法、负极材料、负极极片、电极组件、电池、用电装置和碳基体
CN116885104B (zh) 一种负极极片、二次电池和用电装置
CN113517443B (zh) 一种锂二次电池用聚丙烯腈/二硫化铁复合正极材料的制备方法
CN117423801B (zh) 负极极片及其制备方法、电池
KR102277243B1 (ko) 실리콘 복합체를 포함하는 음극 활물질의 제조방법
CN210136960U (zh) 一种电极极片
JP2002343341A (ja) リチウム二次電池用負極
EP4199233A2 (en) Separator for secondary battery, method of manufacturing the same, and secondary battery including the same

Legal Events

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

Ref document number: 22952343

Country of ref document: EP

Kind code of ref document: A1