WO2023216138A1 - 负极活性材料及其制备方法、二次电池及用电装置 - Google Patents

负极活性材料及其制备方法、二次电池及用电装置 Download PDF

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WO2023216138A1
WO2023216138A1 PCT/CN2022/092211 CN2022092211W WO2023216138A1 WO 2023216138 A1 WO2023216138 A1 WO 2023216138A1 CN 2022092211 W CN2022092211 W CN 2022092211W WO 2023216138 A1 WO2023216138 A1 WO 2023216138A1
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peak
silicon
carbon
sub
active material
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PCT/CN2022/092211
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English (en)
French (fr)
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吕子建
王家政
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宁德时代新能源科技股份有限公司
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Priority to PCT/CN2022/092211 priority Critical patent/WO2023216138A1/zh
Priority to CN202280039907.1A priority patent/CN117425975A/zh
Publication of WO2023216138A1 publication Critical patent/WO2023216138A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • 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, and in particular to a negative active material and a preparation method thereof, a secondary battery and an electrical device.
  • secondary batteries are widely used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, Military equipment, aerospace and other fields.
  • energy storage power systems such as hydraulic, thermal, wind and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, Military equipment, aerospace and other fields.
  • secondary batteries have achieved great development, higher requirements have been placed on their energy density, cycle performance, etc.
  • Silicon-based anode materials are considered to be highly potential next-generation high-energy-density lithium-ion battery anode materials due to their high theoretical specific capacity, low delithiation potential, environmental friendliness, abundant reserves, and low cost.
  • this application provides a new negative active material and its preparation method, a secondary battery and a power device, which are described separately below.
  • the present application provides a negative active material, including a silicon-carbon composite material.
  • the X-ray photoelectron spectrum (XPS) of the silicon-carbon composite material has a Si2p spectrum, and the Si2p spectrum has at least one characteristic peak, so The above characteristic peaks can form the following sub-peaks after peak splitting processing, including:
  • the first subpeak with a binding energy of 99.5 to 99.9eV.
  • the peak area ratio of the first sub-peak and the second sub-peak is 1-2:1.
  • the negative active material of the above solution has higher specific capacity and longer cycle life.
  • the peak area ratio between the first subpeak and the second subpeak is 1 to 2:1 which is critical. If the peak area ratio between the first sub-peak and the second sub-peak is ⁇ 1, it means that the pure silicon content in the negative active material is high and the silicon grains are large, which is detrimental to the lifespan. If the peak area ratio between the first subpeak and the second subpeak is >2, it means that the carbon content in the negative active material is too high, resulting in a low specific capacity of the active material and poor first effect.
  • the above-mentioned negative active material has one or more of the following characteristics:
  • the binding energy of the first sub-peak corresponds to the binding energy of the Si-C bond
  • the second sub-peak is the binding energy corresponding to the binding energy of the Si-Si bond
  • the binding energy of the first sub-peak is 99.6 ⁇ 99.8eV, such as 99.7eV;
  • the binding energy of the second sub-peak is 98.8 ⁇ 99.0eV, such as 98.9eV;
  • the peak area ratio between the first subpeak and the second subpeak is 1.5 to 2:1, such as 1.6 to 1.8:1, such as 1.7:1.
  • the content of silicon element in the silicon-carbon composite material is 95wt% ⁇ 99.9wt% (such as 95wt%, 96wt%, 97wt%, 98wt%, 99wt% or 99.5wt%), and the content of carbon element is 0.1wt% ⁇ 5wt% (eg 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%).
  • the negative active material includes a matrix and the silicon-carbon composite material, and the silicon-carbon composite material is attached to the matrix.
  • the matrix has a porous internal structure, and the silicon-carbon composite material is attached to the matrix at the following locations:
  • the outer surface of the substrate and/or
  • the material of the substrate includes one or more of the following: carbon materials, silicon-oxygen materials, lithium titanate materials, or combinations thereof.
  • the negative active material further includes a carbon coating layer covering the matrix and/or the silicon-carbon composite material
  • the carbon material includes one or more of the following: graphite material, hard carbon material, soft carbon material, or a combination thereof.
  • the silicon-carbon composite material contains silicon crystal grains, and the grain size of the silicon crystal grains is less than 20 nm.
  • the negative active material has a volume median particle diameter D V 50 of 1 to 10 ⁇ m.
  • the peak intensities of the first sub-peak and the second sub-peak are both ⁇ 2000, for example, less than 1500.
  • the present application provides a method for preparing a negative active material, including the following steps:
  • S1 Provide the substrate and vapor deposition equipment.
  • the substrate is placed in the deposition furnace, purged with inert gas in advance and preheated to 200-300°C;
  • S2 Inject gas into the vapor deposition equipment in a first mode, where the first mode includes simultaneously introducing silicon source gas and carbon source gas into the vapor deposition equipment;
  • the X-ray photoelectron spectrum (XPS) of the silicon-carbon composite material has a Si2p peak, and the Si2p peak can form the following sub-peaks after peak splitting processing:
  • the first subpeak with a binding energy of 99.5 to 99.9eV.
  • the peak area ratio of the first sub-peak and the second sub-peak is 1-2:1.
  • the first mode in step S2 includes simultaneously flowing silicon source gas, carbon source gas and inert gas into the vapor deposition equipment.
  • step S2 has one or more of the following characteristics:
  • the inert gas is one or more of nitrogen and argon.
  • step S2 gas is introduced into the vapor deposition equipment in the first mode, and the air pressure in the equipment is maintained to be 200-600 Pa higher than the standard atmospheric pressure.
  • step S3 has one or more of the following characteristics:
  • Step S3 is performed at 400 to 800°C
  • Step S3 lasts for 1 to 12 hours.
  • step S3 further includes step S4:
  • step S4 Deposit carbon material on the product of step S3.
  • step S4 includes the following operations:
  • S4a After forming the silicon-carbon composite material, introduce gas into the vapor deposition equipment according to the second mode.
  • the second mode includes simultaneously introducing carbon source gas and inert gas into the vapor deposition equipment.
  • the proportion of carbon source gas is 5%. ⁇ 15%, the proportion of inert gas is 85% ⁇ 95%;
  • S4b Decompose the carbon source gas into carbon material and deposit it on the silicon-carbon composite material.
  • operation S4b has one or more of the following characteristics:
  • Step S4b is performed at 700 to 850°C;
  • Step S4b lasts for 1-6 hours.
  • the present application provides a negative active material prepared by any of the methods described above.
  • the present application provides a secondary battery including the negative active material according to any one of the above.
  • the present application provides an electrical device including the above-mentioned secondary battery.
  • the negative active material has a high specific capacity
  • the negative active material has a long cycle life
  • Figure 1 is an XPS spectrum of the negative active material of some examples and comparative examples of the present application.
  • Figure 2 is an XRD spectrum of the negative active material of some examples and comparative examples of the present application.
  • Figure 3 is the first cycle charge and discharge curve of button batteries according to some embodiments and comparative examples of the present application.
  • Figure 4 is a capacity retention rate-cycle number curve of the full battery of some embodiments and comparative examples of the present application.
  • FIG. 5 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 6 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. 5 .
  • FIG. 7 is a schematic diagram of a battery module according to an embodiment of the present application.
  • Figure 8 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 9 is an exploded view of the battery pack according to an embodiment of the present application shown in FIG. 8 .
  • FIG. 10 is a schematic diagram of a power consumption device using a secondary battery as a power source according to an embodiment of the present application.
  • 1 battery pack 2 upper box; 3 lower box; 4 battery module; 5 secondary battery; 51 case; 52 electrode assembly; 53 top cover assembly; 11 positive electrode current collector; 112 surface; 12 conductive primer; 13 positive electrode film layer;
  • Ranges disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit that define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive of the endpoints, and may be arbitrarily combined, that is, any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, understand that ranges of 60-110 and 80-120 are also expected. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • the numerical range “a-b” represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers.
  • the numerical range “0-5" means that all real numbers between "0-5" have been listed in this article, and "0-5" is just an abbreviation of these numerical combinations.
  • a certain parameter is an integer ⁇ 2
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • step (c) means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c). , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b), etc.
  • condition "A or B” is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; Or both A and B are true (or exist).
  • Secondary batteries also known as rechargeable batteries or storage batteries, refer to batteries that can be recharged to activate active materials and continue to be used after the battery is discharged.
  • a secondary battery normally includes a positive electrode plate, a negative electrode plate, a separator and an electrolyte.
  • active ions such as lithium ions
  • the isolation film is placed between the positive electrode piece and the negative electrode piece. It mainly prevents the positive and negative electrodes from short-circuiting and allows active ions to pass through.
  • the electrolyte is between the positive electrode piece and the negative electrode piece and mainly plays the role of conducting active ions.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector.
  • the negative electrode film layer includes a negative electrode active material, and the negative electrode active material adopts any one of the negative electrode active materials of the present application.
  • the negative electrode current collector has two opposite surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base material.
  • the composite current collector can be formed by forming metal materials (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative electrode film layer optionally further includes a binder.
  • the binder may be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), At least one of polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer optionally further includes a conductive agent.
  • the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer optionally includes other auxiliaries, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative active materials, conductive agents, binders and any other components in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode piece can be obtained.
  • a solvent such as deionized water
  • the present application provides a negative active material, including a silicon-carbon composite material, the X-ray photoelectron spectrum (XPS) of the silicon-carbon composite material has a Si2p spectrum, and the Si2p spectrum has at least one characteristic peak,
  • the characteristic peaks can form the following sub-peaks after peak splitting processing, including:
  • the first subpeak with a binding energy of 99.5 to 99.9eV.
  • the peak area ratio of the first sub-peak and the second sub-peak is 1-2:1.
  • the negative active material of the above solution has higher specific capacity and longer cycle life.
  • the peak area ratio between the first subpeak and the second subpeak is 1 to 2:1 which is critical. If the peak area ratio between the first sub-peak and the second sub-peak is ⁇ 1, it means that the pure silicon content in the negative active material is high and the silicon grains are large, which is detrimental to the lifespan. If the peak area ratio between the first subpeak and the second subpeak is >2, it means that the carbon content in the negative active material is too high, resulting in a low specific capacity of the active material and poor first effect.
  • the binding energy of the first sub-peak refers to the binding energy corresponding to the peak point of the first sub-peak.
  • the binding energy of the second sub-peak refers to the binding energy corresponding to the peak point of the second sub-peak.
  • the first sub-peak and the second sub-peak have symmetrical peak shapes, such as peaks conforming to a Gaussian function or a Lorenz function.
  • the first subpeak has a binding energy of 99.6 to 99.8 eV, such as 99.7 eV.
  • the second subpeak has a binding energy of 98.8 to 99.0 eV, such as 98.9 eV.
  • the peak area ratio of the first sub-peak to the second sub-peak is 1.5-2:1, such as 1.6-1.8:1, such as 1.7:1.
  • the above-mentioned negative active material has one or more of the following characteristics: (1) the binding energy of the first sub-peak corresponds to the binding energy of the Si-C bond; (2) the second sub-peak is The binding energy corresponds to the binding energy of the Si-Si bond. Based on this, the negative active material has further improved specific capacity, first efficiency and/or cycle life.
  • the binding energy of the first sub-peak is 99.6 ⁇ 99.8eV, such as 99.7eV; (4) The binding energy of the second sub-peak is 98.8 ⁇ 99.0eV, such as 98.9eV; (5) The first sub-peak and the second The peak area ratio of sub-peaks is 1.5 ⁇ 2:1; (6)
  • the content of silicon element in the silicon-carbon composite material is 95 ⁇ 99.9wt% (such as 95wt%, 96wt%, 97wt%, 98wt%, 99wt% or 99.5wt %), the content of carbon element is 0.1 to 5wt% (for example, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%).
  • negative active materials are used in secondary batteries, and the secondary batteries exhibit further improved specific capacity, first efficiency, and/or cycle endurance.
  • the negative active material includes a matrix and the silicon-carbon composite material, and the silicon-carbon composite material is attached to the matrix. Based on this, the negative active material has further improved specific capacity, first efficiency and/or cycle life.
  • the matrix has a porous internal structure
  • the silicon-carbon composite material is attached to the matrix at: an outer surface of the matrix; and/or in the pores of the porous internal structure. Based on this, the negative active material has further improved specific capacity, first efficiency and/or cycle life.
  • the material of the substrate includes one or more of the following: carbon materials, silicon-oxygen materials, lithium titanate materials, or combinations thereof. Based on this, the negative active material has further improved specific capacity, first efficiency and/or cycle life.
  • the negative active material further includes a carbon coating layer covering the matrix and/or the silicon-carbon composite material. Based on this, the negative active material has further improved specific capacity, first efficiency and/or cycle life.
  • the carbon material includes one or more of the following: graphite material, hard carbon material, soft carbon material, or a combination thereof. Based on this, the negative active material has further improved specific capacity, first efficiency and/or cycle life.
  • the silicon-carbon composite material contains silicon crystal grains, and the grain size of the silicon crystal grains is less than 20 nm. Based on this, the negative active material has further improved specific capacity, first efficiency and/or cycle life.
  • the negative active material has a volume median particle diameter D V 50 of 1 to 10 ⁇ m (eg, 2 ⁇ m, 4 ⁇ m, 6 ⁇ m, or 8 ⁇ m). Based on this, the negative active material has further improved specific capacity, first efficiency and/or cycle life.
  • the peak intensities of the first sub-peak and the second sub-peak are both ⁇ 2000, for example, less than 1500.
  • the present application provides a method for preparing a negative active material, including the following steps:
  • S1 Provide the substrate and vapor deposition equipment.
  • the substrate is placed in the deposition furnace, purged with inert gas in advance and preheated to 200-300°C;
  • S2 Inject gas into the vapor deposition equipment in a first mode, where the first mode includes simultaneously introducing silicon source gas and carbon source gas into the vapor deposition equipment;
  • the X-ray photoelectron spectrum (XPS) of the silicon-carbon composite material has a Si2p peak, and the Si2p peak can form the following sub-peaks after peak splitting processing:
  • the first subpeak with a binding energy of 99.5 to 99.9eV.
  • the peak area ratio of the first sub-peak and the second sub-peak is 1-2:1.
  • the negative active materials obtained based on this approach have improved specific capacity, first efficiency and/or cycle life.
  • the first mode in step S2 includes simultaneously flowing silicon source gas, carbon source gas and inert gas into the vapor deposition equipment.
  • the negative active materials obtained based on this approach have improved specific capacity, first efficiency and/or cycle life.
  • step S2 has one or more of the following characteristics:
  • the inert gas is one or more of nitrogen and argon;
  • step S2 gas is introduced into the vapor deposition equipment in the first mode, and the air pressure in the equipment is maintained to reach 200-600 Pa (for example, 300 Pa, 400 Pa, 500 Pa) higher than the standard atmospheric pressure.
  • 200-600 Pa for example, 300 Pa, 400 Pa, 500 Pa
  • the negative active materials obtained based on this approach have improved specific capacity, first efficiency and/or cycle life.
  • step S3 has one or more of the following characteristics:
  • Step S3 is performed at 400 to 800°C (such as 500°C, 600°C or 700°C);
  • Step S3 lasts for 1 to 12 hours (for example, 2 hours, 4 hours, 6 hours, 8 hours or 10 hours).
  • the negative active materials obtained based on this approach have improved specific capacity, first efficiency and/or cycle life.
  • step S3 further includes step S4:
  • step S4 Deposit carbon material on the product of step S3.
  • the negative active materials obtained based on this approach have improved specific capacity, first efficiency and/or cycle life.
  • step S4 includes the following operations:
  • S4a After forming the silicon-carbon composite material, introduce gas into the vapor deposition equipment according to the second mode.
  • the second mode includes simultaneously introducing carbon source gas and inert gas into the vapor deposition equipment.
  • the proportion of carbon source gas is 5%. ⁇ 15%, the proportion of inert gas is 85% ⁇ 95%;
  • S4b Decompose the carbon source gas into carbon material and deposit it on the silicon-carbon composite material.
  • the negative active materials obtained based on this approach have improved specific capacity, first efficiency and/or cycle life.
  • operation S4b has one or more of the following characteristics:
  • Step S4b is performed at 700 to 850°C (for example, 750 to 800°C);
  • Step S4b lasts for 1-6 hours (for example, 2 hours, 3 hours, 4 hours or 5 hours).
  • the negative active materials obtained based on this approach have improved specific capacity, first efficiency and/or cycle life.
  • the present application provides a negative active material prepared by any of the methods described above.
  • the present application provides a secondary battery including the negative active material described in any one of the above.
  • the present application provides an electrical device including the above-mentioned secondary battery.
  • the positive electrode sheet generally includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector.
  • the positive electrode film layer includes a positive electrode active material.
  • the positive electrode current collector has two surfaces facing each other in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • the metal foil aluminum foil can be used.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the cathode active material may be a cathode active material known in the art for batteries.
  • the cathode active material may include at least one of the following materials: an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials of batteries can also be used. Only one type of these positive electrode active materials may be used alone, or two or more types may be used in combination.
  • lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), lithium manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium Nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/5 n 1/3 O 2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (can also be abbreviated to NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (can also be abbreviated to NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (can also be abbreviated to NCM 622 ), LiNi At least one of 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as Li
  • the olivine structure contains Examples of lithium phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), composites of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), lithium manganese phosphate and carbon. At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also referred to as LFP)
  • composites of lithium iron phosphate and carbon such as LiMnPO 4
  • LiMnPO 4 lithium manganese phosphate and carbon.
  • At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.
  • the positive electrode film layer optionally further includes a binder.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene tripolymer. At least one of a meta-copolymer, a tetrafluoroethylene-hexafluoropropylene copolymer and a fluorine-containing acrylate resin.
  • the positive electrode film layer optionally further includes a conductive agent.
  • the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components in a solvent (such as N -methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode piece can be obtained.
  • a solvent such as N -methylpyrrolidone
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • the type of electrolyte in this application can be selected according to needs.
  • the electrolyte can be liquid, gel, or completely solid.
  • the electrolyte is liquid and includes an electrolyte salt and a solvent.
  • the electrolyte salt may be selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonimide, lithium bistrifluoromethanesulfonimide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluoroborate, lithium dioxaloborate, lithium difluorodioxalate phosphate and lithium tetrafluoroxalate phosphate.
  • the solvent may be selected from the group consisting of ethylene carbonate, propylene carbonate, methylethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, Butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate At least one of ester, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the electrolyte optionally also includes additives.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain properties of the battery, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.
  • the secondary battery further includes a separator film.
  • a separator film There is no particular restriction on the type of isolation membrane in this application. Any well-known porous structure isolation membrane with good chemical stability and mechanical stability can be used.
  • the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the isolation film can be a single-layer film or a multi-layer composite film, with no special restrictions. When the isolation film is a multi-layer composite film, the materials of each layer can be the same or different, and there is no particular limitation.
  • the positive electrode piece, the negative electrode piece and the separator film can be made into an electrode assembly through a winding process or a lamination process.
  • the secondary battery may include an outer packaging.
  • the outer packaging can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the secondary battery may also be a soft bag, such as a bag-type soft bag.
  • the material of the soft bag may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 5 shows a square-structured secondary battery 5 as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose a receiving cavity.
  • the housing 51 has an opening communicating with the accommodation cavity, and the cover plate 53 can cover the opening to close the accommodation cavity.
  • the positive electrode piece, the negative electrode piece and the isolation film can be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the containing cavity.
  • the electrolyte soaks into the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.
  • secondary batteries can be assembled into battery modules, and the number of secondary batteries contained in the battery module can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery module.
  • FIG. 7 shows the battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4 .
  • the plurality of secondary batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having a receiving space in which a plurality of secondary batteries 5 are received.
  • the above-mentioned battery modules can also be assembled into a battery pack.
  • the number of battery modules contained in the battery pack can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box 2 and a lower box 3 .
  • the upper box 2 can be covered with the lower box 3 and form a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided by the present application.
  • the secondary battery, battery module, or battery pack may be used as a power source for the electrical device, or may be used as an energy storage unit for the electrical device.
  • the electric device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, and electric golf carts). , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited to these.
  • a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.
  • Figure 10 is an electrical device as an example.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc.
  • a battery pack or battery module can be used.
  • composition of silicon-oxygen material is as follows: Li 8wt%, Si 52wt%, O 35.8wt%, C 4.2wt%.
  • S1 The same silicone material as Comparative Example 1 is provided as the matrix. Provides chemical vapor deposition (CVD) equipment. Place 1kg of substrate in the reaction chamber of the chemical vapor deposition equipment. Purge the reaction chamber with nitrogen and raise the temperature of the reaction chamber to 200°C.
  • CVD chemical vapor deposition
  • the total gas flow is 5L/min, and control the pressure in the reaction chamber to be 200Pa higher than the atmospheric pressure.
  • S4 Inject the mixed gas into the reaction chamber in the second mode.
  • Example 1 After the product is cooled, it is taken out from the reaction chamber and sieved to 325 mesh. The negative electrode active material of Example 1 was obtained.
  • the negative active material of Embodiment 1 includes a substrate, a first coating layer deposited on the surface of the substrate, and a second coating layer deposited on the surface of the first coating layer.
  • the material of the substrate is silicone material.
  • the material of the first coating layer is silicon carbon composite material.
  • the second coating layer is made of carbon material.
  • the solvent of the electrolyte is a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC), where the volume ratio of EC, EMC and DEC is 20:20:60.
  • the solute of the electrolyte is LiPF 6 and the concentration is 1 mol/L.
  • the electrolyte also contains the additive fluoroethylene carbonate (FEC), and the content of FEC in the electrolyte is 5 wt%.
  • the anode active materials of the examples and comparative examples were tested using an X-ray photoelectron spectrometer (Thermo Scientific ESCALAB Xi+) to obtain the Si2p energy spectrum of the material.
  • XPSpeak software was used to perform peak splitting and fitting processing on the characteristic peaks of the Si2p energy spectrum.
  • the Si2p energy spectrum of the negative active material of Comparative Example 1 has a characteristic peak in the range of 100 to 104 eV, and the binding energy of this characteristic peak is 102.3 eV, corresponding to the binding energy of the Si-O-C bond.
  • FIG. 1 shows the Si2p energy spectrum of the negative electrode active material of Example 1.
  • the Si2p energy spectrum of the negative active material of Example 1 has an original curve 100.
  • the original curve 100 has a characteristic peak at 98 ⁇ 101eV and 101 ⁇ 105eV.
  • a fitting curve 200 can be formed by performing peak split fitting processing on the characteristic peaks at 98 to 101 eV.
  • the fitting curve 200 appears as the superposition of two sub-peaks at the position of 101-105 eV.
  • the two sub-peaks include:
  • the first sub-peak 201 with a binding energy of 99.7eV (corresponding to the binding energy of Si-C bond);
  • the second sub-peak 202 with a binding energy of 98.9eV (corresponding to the binding energy of Si-Si bond);
  • the ratio A Si-C /A Si-Si between the peak area A Si-C of the first sub-peak 201 and the peak area A Si- Si of the second sub-peak 202 is 1.7.
  • the peak intensities of the first subpeak and the second subpeak are both ⁇ 2000.
  • the A Si-C /A Si-Si test results of each embodiment and comparative example are shown in Table 2.
  • the XRD spectrum of the above silicon carbon material was tested using a Bruker D8 Discover X-ray diffractometer. The test angle range was 20°-80°. After obtaining the data, X’Pert Highscore plus software was used for fitting, and the grain size of the silicon (1 1 1) crystal plane corresponding to 28.5° ⁇ 0.1° was calculated according to Scherrer’s formula.
  • Example 1 and Comparative Example 1 are shown in Figure 2.
  • the diffraction peaks of Li 2 SiO 3 and Si can be observed in the XRD spectrum of the negative active material of Comparative Example 1.
  • the distribution of the diffraction peaks in the XRD spectrum of the negative active material of Example 1 is basically consistent with that of the comparative example, but the intensity of the diffraction peaks is weakened. This shows that the silicon-carbon composite material and carbon material deposited on the substrate in Example 1 basically have no diffraction peaks and basically have an amorphous structure.
  • the silicon grain size calculated based on Scherrer's formula is shown in the table below.
  • the average size of silicon crystal grains in the negative electrode active materials of Comparative Example 1 and Example 1 is in the range of 6 nm to 8 nm.
  • the particle size distribution data of the negative electrode active materials of the Examples and Comparative Examples measured based on the laser diffraction method are shown in the table below. These include volume distribution particle size data Dv10 ( ⁇ m), Dv50 ( ⁇ m), Dv90 ( ⁇ m) and Dv99 ( ⁇ m), and number particle size distribution data D N 10 ( ⁇ m).
  • the particle size testing method refers to the laser diffraction method commonly used in this field, such as GB/T 19077-2016 particle size distribution laser diffraction method.
  • the particle size distribution data of the negative active materials of Example 1 and Comparative Example 1 are shown in Table 1.
  • the elemental components of the negative active material prepared in Example 1 were detected according to the following test methods.
  • Carbon content test According to the GB/T 20123-2006/ISO 15350:2000 test standard, the HSC-140 carbon content analyzer is used to test the carbon content of the material.
  • composition of the negative active material of Example 1 is as follows: Li 6.8wt%, Si 57wt%, O 29.7wt%, C 6.5wt%.
  • the silicon-carbon composite material constituting the first coating layer has the following composition: silicon content 97.5% and carbon content 2.5% (calculated based on silicon content/carbon content before and after deposition).
  • the test results of each embodiment and comparative example are shown in Table 2.
  • the first week cycle efficiency test process is as follows:
  • the assembled button battery is left to stand for 60 minutes.
  • Lithium embedding capacity First use 0.05C constant current to discharge to 5mV, then use 50 ⁇ A to discharge to 5mV, and let it stand for 10 minutes.
  • Lithium removal capacity charge to 1.5V using 0.1C.
  • the first cycle efficiency (referred to as first effect) is calculated by the following formula:
  • the negative active material of Example 1 has significantly improved lithium removal capacity and lithium insertion capacity.
  • the first effect of the negative active material of Example 1 is basically equivalent to that of Comparative Example 1.
  • the test results of each embodiment and comparative example are shown in Table 2.
  • the positive electrode slurry formula is as follows: mix the positive NCM ternary material, conductive agent Super P, and binder polyvinylidene fluoride (PVDF) in a mass ratio of 97:1.5:1.5, and add the solvent N-methylpyrrolidone (NMP). Stir under the action of a vacuum mixer until the system is uniform, and obtain a cathode slurry with a solid content of 77wt%.
  • the positive electrode slurry is evenly coated on the positive electrode current collector aluminum foil and dried at 85°C, then cold pressed, trimmed, slitted, and cut into pieces, and finally dried under vacuum conditions at 85°C for 4 hours to obtain the desired result.
  • Use positive pole pieces are used in
  • the negative electrode slurry formula is as follows: mix the negative active material (90% graphite, 10% silicon), conductive agent (including CNTs), thickener sodium carboxymethylcellulose (CMC), and binder styrene-butadiene rubber (SBR) according to After mixing with a mass ratio of 96.2:1.3:1.0:1.5, add the solvent deionized water, stir under the action of a vacuum mixer until the system is uniform, and obtain an anode slurry with a solid content of 52%; apply the anode slurry evenly on the first A layer of negative electrode film is dried at 85°C, then cold pressed, trimmed, slitted, and cut into pieces, and finally dried under vacuum conditions at 120°C for 12 hours to obtain the negative electrode piece to be used.
  • SBR styrene-butadiene rubber
  • the organic solvent is a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC), where the volume ratio of EC, EMC and DEC is 20:20:60 .
  • EC ethylene carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • the concentration of lithium salt is 1mol/L.
  • the positive electrode slurry is coated on the aluminum foil current collector to obtain the positive electrode sheet, and the negative electrode slurry is coated on the copper foil current collector to obtain the negative electrode sheet.
  • the positive electrode sheet, separator, and negative electrode sheet are stacked and wound and then placed in the battery casing. Electrolyte is injected and sealed to obtain a full battery.
  • the full battery was subjected to a charge and discharge cycle test with a charge and discharge rate of 0.5C/1C and a cut-off voltage of 2.5-4.25V.
  • the capacity retention rate-cycle number curve was obtained during the test, as shown in Figure 4.
  • the 200-cycle retention rate test results of each embodiment and comparative example are shown in Table 2 below.
  • Example 1 As shown in Table 2 and Figure 4, after 200 cycles of the full batteries of Example 1 and Comparative Example 1, the capacity retention rates were 96.6% and 96.8% respectively.
  • the capacity retention rates of Example 1 and Comparative Example 1 are basically equivalent.
  • the material of Example 1 not only significantly increases the specific capacity, but also maintains a good capacity retention rate.
  • the energy densities of the full batteries of Example 1 and Comparative Example 1 are 276Wh/kg and 266Wh/kg respectively, and the energy density is increased by 3.8%.
  • the energy density test results of each embodiment and comparative example are shown in Table 2 below.
  • the peak area ratio of the first sub-peak to the second sub-peak of the XPS Si2p spectrum of the negative active material of Examples 1 to 3 is 1 to 2:1.
  • the negative active material is used in secondary batteries, and the batteries exhibit improved specific capacity, improved first efficiency, and better cycle life.
  • the peak area ratio between the first sub-peak and the second sub-peak is ⁇ 1.
  • the negative active material has a high pure silicon content and large silicon grains. Bad for life span.
  • the peak area ratio between the first subpeak and the second subpeak of Comparative Example 2 is >2.
  • the carbon content in the negative active material is too high, resulting in a low specific capacity of the active material and poor first effect.

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Abstract

一种负极活性材料及其制备方法、二次电池及用电装置。负极活性材料包括硅碳复合材料，硅碳复合材料的X射线光电子能谱（XPS）具有Si2p峰，Si2p峰经分峰处理后能够形成以下亚峰：结合能为99.7±0.2eV的第一亚峰；以及结合能为98.9±0.2eV的第二亚峰；第一亚峰与第二亚峰的峰面积比值为1-2:1。

Description

负极活性材料及其制备方法、二次电池及用电装置 技术领域
本申请涉及电池技术领域，尤其涉及一种负极活性材料及其制备方法、二次电池及用电装置。
背景技术
近年来，随着二次电池的应用范围越来越广泛，二次电池广泛应用于水力、火力、风力和太阳能电站等储能电源系统，以及电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。由于二次电池取得了极大的发展，因此对其能量密度、循环性能等也提出了更高的要求。
硅基负极材料因其较高的理论比容量、较低的脱锂电位、环境友好、储量丰富、成本较低等优势而被认为是极具潜力的下一代高能量密度锂离子电池负极材料。
为了进一步提升电池性能，现有技术需要更优的负极活性材料。
发明内容
鉴于上述课题，本申请提供一种新型负极活性材料及其制备方法、二次电池及用电装置，下面分别描述。
在第一方面，本申请提供一种负极活性材料，包括硅碳复合材料，所述硅碳复合材料的X射线光电子能谱(XPS)具有Si2p谱，所述Si2p谱具有至少一个特征峰，所述特征峰经分峰处理后能够形成以下亚峰，包括：
结合能为99.5～99.9eV的第一亚峰；以及
结合能为98.7～99.1eV的第二亚峰；
所述第一亚峰与第二亚峰的峰面积比值为1～2：1。
上述方案的负极活性材料具有较高的比容量和较长的循环寿命。第一亚峰与第二亚峰的峰面积比值为1～2：1是关键的。若第一亚峰与第二亚峰的峰面积比值<1，说明负极活性材料中纯硅含量高，硅晶粒较大，对寿命不利。若第一亚峰与第二亚峰的峰面积比值>2，说明负极活性材料中碳含量过高，导致活性材料的比容量较低，首效不佳。
在一些实施方式中，上述负极活性材料具有以下一项或多项特征：
(1)所述第一亚峰的结合能对应Si-C键的结合能；
(2)所述第二亚峰是结合能对应Si-Si键的结合能；
(3)第一亚峰的结合能为99.6～99.8eV，例如99.7eV；
(4)第二亚峰的结合能为98.8～99.0eV，例如98.9eV；
(5)第一亚峰与第二亚峰的峰面积比值为1.5～2：1，例如1.6～1.8：1，例如1.7：1。
(6)硅碳复合材料中硅元素的含量为95wt％～99.9wt％(例如95wt％、96wt％、97wt％、98wt％、99wt％或99.5wt％)，碳元素的含量为0.1wt％～5wt％(例如0.5wt％、1wt％、 2wt％、3wt％、4wt％、5wt％)。
在一些实施方式中，所述负极活性材料包括基体和所述硅碳复合材料，所述硅碳复合材料附着在所述基体上。
在一些实施方式中，所述基体的具有多孔内部结构，所述硅碳复合材料附着在所述基体以下位置：
所述基体的外表面；和/或
所述多孔内部结构的孔隙中。
在一些实施方式中，所述基体的材质包括以下一项或多项：碳材料、硅氧材料、钛酸锂材料、或其组合。
在一些实施方式中，所述负极活性材料还包括碳包覆层，所述碳包覆层覆盖所述基体和/或所述硅碳复合材料
在一些实施方式中，所述碳材料包括以下一项或多项：石墨材料、硬碳材料、软碳材料、或其组合。
在一些实施方式中，所述硅碳复合材料含有硅晶粒，所述硅晶粒的晶粒尺寸为20nm以下。
在一些实施方式中，所述负极活性材料的体积中值粒径D V50为1～10μm。
在一些实施方式中，所述第一亚峰与第二亚峰的峰强度均<2000，例如小于1500。
在第二方面，本申请提供一种制备负极活性材料的方法，包括以下步骤：
S1：提供基体和气相沉积设备，所述基体放置于沉积炉内，并预先用惰性气体吹扫且升温预热至200-300℃；
S2：按第一模式向气相沉积设备内通入气体，所述第一模式包括向气相沉积设备同时通入硅源气体和碳源气体；
S3：使硅源气体和碳源气体反应并使反应产物在基体上沉积，在基体上形成硅碳复合材料；
所述硅碳复合材料的X射线光电子能谱(XPS)具有Si2p峰，所述Si2p峰经分峰处理后能够形成以下亚峰：
结合能为99.5～99.9eV的第一亚峰；以及
结合能为98.7～99.1eV的第二亚峰；
所述第一亚峰与第二亚峰的峰面积比值为1～2：1。
在一些实施方式中，步骤S2中所述第一模式包括向气相沉积设备同时通入硅源气体、碳源气体和惰性气体。
在一些实施方式中，步骤S2具有以下一项或多项特征：
(1)所述惰性气体为氮气、氩气中的一种或多种。
(2)向气相沉积设备通入的惰性气体的流量占全部通入气体流量的30-85体积％。
在一些实施方式中，步骤S2中，按第一模式向气相沉积设备内通入气体，并保持设备内气压达到高于标准大气压的200～600Pa。
在一些实施方式中，步骤S3具有以下一项或多项特征：
(1)步骤S3在400～800℃下进行；
(2)步骤S3持续1～12小时。
在一些实施方式中，步骤S3之后还包括步骤S4：
S4：在步骤S3的产物上沉积碳材料。
在一些实施方式中，步骤S4包括以下操作：
S4a：形成硅碳复合材料之后，按第二模式向气相沉积设备内通入气体，所述第二模式包括向气相沉积设备同时通入碳源气体和惰性气体，碳源气体占比为5％～15％，惰性气体占比为85％～95％；
S4b：使碳源气体分解为碳材料并沉积在硅碳复合材料上。
在一些实施方式中，操作S4b具有以下一项或多项特征：
(1)步骤S4b在700～850℃进行；
(2)步骤S4b持续1-6小时。
在第三方面，本申请提供一种负极活性材料，由上述任一项所述的方法制备获得。
在第四方面，本申请提供一种二次电池，包括上述任一项所述的负极活性材料。
在第五方面，本申请提供一种用电装置，包括上述的二次电池。
有益效果
本申请一个或多个实施方式具有以下一项或多项有益效果：
(1)负极活性材料具有较高的比容量；
(2)负极活性材料具有较长的循环寿命；
(3)负极活性材料的制备方法具有较低的成本；
(4)负极活性材料的制备方法具有较高的效率。
附图说明
图1是本申请一些实施例和对比例的负极活性材料的XPS谱图。
图2是本申请一些实施例和对比例的负极活性材料的XRD谱图。
图3是本申请一些实施例和对比例的扣式电池的首周循环充放电曲线。
图4是本申请一些实施例和对比例的全电池的容量保持率-循环周数曲线。
图5是本申请一实施方式的二次电池的示意图。
图6是图5所示的本申请一实施方式的二次电池的分解图。
图7是本申请一实施方式的电池模块的示意图。
图8是本申请一实施方式的电池包的示意图。
图9是图8所示的本申请一实施方式的电池包的分解图。
图10是本申请一实施方式的二次电池用作电源的用电装置的示意图。
附图标记说明：
1电池包；2上箱体；3下箱体；4电池模块；5二次电池；51壳体；52电极组件；53顶盖组件；11正极集流体；112表面；12导电底涂层；13正极膜层；
具体实施方式
以下，适当地参照附图详细说明具体公开了本申请的负极活性材料及其制造方法、正极极片、负极极片、二次电池、电池模块、电池包和装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都 为真(或存在)。
[二次电池]
二次电池又称为充电电池或蓄电池，是指在电池放电后可通过充电的方式使活性材料激活而继续使用的电池。
通常情况下，二次电池包括正极极片、负极极片、隔离膜及电解液。在电池充放电过程中，活性离子(例如锂离子)在正极极片和负极极片之间往返嵌入和脱出。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的作用，同时可以使活性离子通过。电解液在正极极片和负极极片之间，主要起到传导活性离子的作用。
[负极极片]
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，所述负极膜层包括负极活性材料，负极活性材料采用本申请任一项的负极活性材料。
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极膜层设置在负极集流体相对的两个表面中的任意一者或两者上。
在一些实施方式中，负极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，负极膜层还可选地包括粘结剂。作为示例，粘结剂可选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的至少一种。
在一些实施方式中，负极膜层还可选地包括导电剂。作为示例，导电剂可选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，负极膜层还可选地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。
在一些实施方式中，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到负极极片。
[负极活性材料]
在一些实施方式中，本申请提供一种负极活性材料，包括硅碳复合材料，所述硅碳复合材料的X射线光电子能谱(XPS)具有Si2p谱，所述Si2p谱具有至少一个特征峰，所述特征峰经分峰处理后能够形成以下亚峰，包括：
结合能为99.5～99.9eV的第一亚峰；以及
结合能为98.7～99.1eV的第二亚峰；
所述第一亚峰与第二亚峰的峰面积比值为1～2：1。
上述方案的负极活性材料具有较高的比容量和较长的循环寿命。第一亚峰与第二亚峰的峰面积比值为1～2:1是关键的。若第一亚峰与第二亚峰的峰面积比值<1，说明负极活性材料中纯硅含量高，硅晶粒较大，对寿命不利。若第一亚峰与第二亚峰的峰面积比值>2，说明负极活性材料中碳含量过高，导致活性材料的比容量较低，首效不佳。
在一些实施方式中，第一亚峰的结合能是指第一亚峰的峰值点所对应的结合能。
在一些实施方式中，第二亚峰的结合能是指第二亚峰的峰值点所对应的结合能。
在一些实施方式中，第一亚峰和第二亚峰具有对称峰形，例如是符合高斯函数或洛伦茨函数的峰。
在一些实施方案中，第一亚峰的结合能为99.6～99.8eV，例如99.7eV。
在一些实施方案中，第二亚峰的结合能为98.8～99.0eV，例如98.9eV。
在一些实施方案中，第一亚峰与第二亚峰的峰面积比值为1.5～2：1，例如1.6～1.8：1，例如1.7：1。
在一些实施方式中，上述负极活性材料具有以下一项或多项特征：(1)所述第一亚峰的结合能对应Si-C键的结合能；(2)所述第二亚峰是结合能对应Si-Si键的结合能。基于此，负极活性材料具有进一步改善的比容量、首效和/或循环寿命。(3)第一亚峰的结合能为99.6～99.8eV，例如99.7eV；(4)第二亚峰的结合能为98.8～99.0eV，例如98.9eV；(5)第一亚峰与第二亚峰的峰面积比值为1.5～2：1；(6)硅碳复合材料中硅元素的含量为95～99.9wt％(例如95wt％、96wt％、97wt％、98wt％、99wt％或99.5wt％)，碳元素的含量为0.1～5wt％(例如0.5wt％、1wt％、2wt％、3wt％、4wt％、5wt％)。
基于此，负极活性材料用于二次电池，二次电池表现出进一步改善的比容量、首效和/或循环受吗。
在一些实施方式中，所述负极活性材料包括基体和所述硅碳复合材料，所述硅碳复合材料附着在所述基体上。基于此，负极活性材料具有进一步改善的比容量、首效和/或循环寿命。
在一些实施方式中，所述基体的具有多孔内部结构，所述硅碳复合材料附着在所述基体以下位置：所述基体的外表面；和/或所述多孔内部结构的孔隙中。基于此，负极活性材料具有进一步改善的比容量、首效和/或循环寿命。
在一些实施方式中，所述基体的材质包括以下一项或多项：碳材料、硅氧材料、钛酸锂材料、或其组合。基于此，负极活性材料具有进一步改善的比容量、首效和/或循环寿命。
在一些实施方式中，所述负极活性材料还包括碳包覆层，所述碳包覆层覆盖所述基体和/或所述硅碳复合材料。基于此，负极活性材料具有进一步改善的比容量、首效和/或循环寿命。
在一些实施方式中，所述碳材料包括以下一项或多项：石墨材料、硬碳材料、软碳材 料、或其组合。基于此，负极活性材料具有进一步改善的比容量、首效和/或循环寿命。
在一些实施方式中，所述硅碳复合材料含有硅晶粒，所述硅晶粒的晶粒尺寸为20nm以下。基于此，负极活性材料具有进一步改善的比容量、首效和/或循环寿命。
在一些实施方式中，所述负极活性材料的体积中值粒径D V50为1～10μm(例如2μm、4μm、6μm或8μm)。基于此，负极活性材料具有进一步改善的比容量、首效和/或循环寿命。
在一些实施方式中，所述第一亚峰与第二亚峰的峰强度均<2000，例如小于1500。
在一些实施方式中，本申请提供一种制备负极活性材料的方法，包括以下步骤：
S1：提供基体和气相沉积设备，所述基体放置于沉积炉内，并预先用惰性气体吹扫且升温预热至200-300℃；
S2：按第一模式向气相沉积设备内通入气体，所述第一模式包括向气相沉积设备同时通入硅源气体和碳源气体；
S3：使硅源气体和碳源气体反应并使反应产物在基体上沉积，在基体上形成硅碳复合材料；
所述硅碳复合材料的X射线光电子能谱(XPS)具有Si2p峰，所述Si2p峰经分峰处理后能够形成以下亚峰：
结合能为99.5～99.9eV的第一亚峰；以及
结合能为98.7～99.1eV的第二亚峰；
所述第一亚峰与第二亚峰的峰面积比值为1～2：1。
基于此方案获得的负极活性材料具有改善的比容量、首效和/或循环寿命。
在一些实施方式中，步骤S2中所述第一模式包括向气相沉积设备同时通入硅源气体、碳源气体和惰性气体。基于此方案获得的负极活性材料具有改善的比容量、首效和/或循环寿命。
在一些实施方式中，步骤S2具有以下一项或多项特征：
(1)所述惰性气体为氮气、氩气中的一种或多种；
(2)向气相沉积设备通入的惰性气体的流量占全部通入气体流量的30-85体积％。基于此方案获得的负极活性材料具有改善的比容量、首效和/或循环寿命。
在一些实施方式中，步骤S2中，按第一模式向气相沉积设备内通入气体，并保持设备内气压达到高于标准大气压的200～600Pa(例如300Pa、400Pa、500Pa)。基于此方案获得的负极活性材料具有改善的比容量、首效和/或循环寿命。
在一些实施方式中，步骤S3具有以下一项或多项特征：
(1)步骤S3在400～800℃(例如500℃、600℃或700℃)下进行；
(2)步骤S3持续1～12小时(例如2小时、4小时、6小时、8小时或10小时)。基于此方案获得的负极活性材料具有改善的比容量、首效和/或循环寿命。
在一些实施方式中，步骤S3之后还包括步骤S4：
S4：在步骤S3的产物上沉积碳材料。基于此方案获得的负极活性材料具有改善的比 容量、首效和/或循环寿命。
在一些实施方式中，步骤S4包括以下操作：
S4a：形成硅碳复合材料之后，按第二模式向气相沉积设备内通入气体，所述第二模式包括向气相沉积设备同时通入碳源气体和惰性气体，碳源气体占比为5％～15％，惰性气体占比为85％～95％；
S4b：使碳源气体分解为碳材料并沉积在硅碳复合材料上。基于此方案获得的负极活性材料具有改善的比容量、首效和/或循环寿命。
在一些实施方式中，操作S4b具有以下一项或多项特征：
(1)步骤S4b在700～850℃(例如750～800℃)进行；
(2)步骤S4b持续1-6小时(例如2小时、3小时、4小时或5小时)。基于此方案获得的负极活性材料具有改善的比容量、首效和/或循环寿命。
在一些实施方式中，本申请提供一种负极活性材料，由上述任一项所述的方法制备获得。
在一些实施方式中，本申请提供一种二次电池，包括上述任一项所述的负极活性材料。
在一些实施方式中，本申请提供一种用电装置，包括上述的二次电池。
[正极极片]
在一些实施方式中，正极极片通常包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，正极膜层包括正极活性材料。
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极膜层设置在正极集流体相对的两个表面的其中任意一者或两者上。
在一些实施方式中，正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，正极活性材料可采用本领域公知的用于电池的正极活性材料。作为示例，正极活性材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作电池正极活性材料的传统材料。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO 2)、锂镍氧化物(如LiNiO 2)、锂锰氧化物(如LiMnO 2、LiMn 2O 4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(如LiNi 1/3Co 1/5n 1/3O 2(也可以简称为NCM 333)、LiNi 0.5Co 0.2Mn 0.3O 2(也可以简称为NCM 523)、LiNi 0.5Co 0.25Mn 0.25O 2(也可以简称为NCM 211)、LiNi 0.6Co 0.2Mn 0.2O 2(也可以简称为NCM 622)、LiNi 0.8Co 0.1Mn 0.1O 2(也可以简称为NCM 811)、锂镍钴铝氧化物(如LiNi 0.85Co 0.15Al 0.05O 2)及其改性化合物等中的至少一种。橄榄石结构 的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO 4(也可以简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO 4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料中的至少一种。
在一些实施方式中，正极膜层还可选地包括粘结剂。作为示例，粘结剂可以包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。
在一些实施方式中，正极膜层还可选地包括导电剂。作为示例，导电剂可以包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片。
[电解质]
电解质在正极极片和负极极片之间起到传导离子的作用。本申请对电解质的种类没有具体的限制，可根据需求进行选择。例如，电解质可以是液态的、凝胶态的或全固态的。
在一些实施方式中，电解质为液态的，且包括电解质盐和溶剂。
在一些实施方式中，电解质盐可选自六氟磷酸锂、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三氟甲磺酸锂、二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、二氟二草酸磷酸锂及四氟草酸磷酸锂中的至少一种。
在一些实施方式中，溶剂可选自碳酸亚乙酯、碳酸亚丙酯、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1,4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种。
在一些实施方式中，电解液还可选地包括添加剂。作为示例，添加剂可以包括负极成膜添加剂、正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。
[隔离膜]
在一些实施方式中，二次电池中还包括隔离膜。本申请对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。
在一些实施方式中，隔离膜的材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的至少一种。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电 极组件。
在一些实施方式中，二次电池可包括外包装。该外包装可用于封装上述电极组件及电解质。
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，作为塑料，可列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。例如，图5是作为一个示例的方形结构的二次电池5。
在一些实施方式中，参照图6，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔内。电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或多个，本领域技术人员可根据具体实际需求进行选择。
在一些实施方式中，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为一个或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。
图7是作为一个示例的电池模块4。参照图7，在电池模块4中，多个二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间。
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以为一个或多个，具体数量本领域技术人员可根据电池包的应用和容量进行选择。
图8和图9是作为一个示例的电池包1。参照图8和图9，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
另外，本申请还提供一种用电装置，所述用电装置包括本申请提供的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以包括移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等，但不限于此。
作为所述用电装置，可以根据其使用需求来选择二次电池、电池模块或电池包。
图10是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对二次电池的高功率和高能量密度的需求， 可以采用电池包或电池模块。
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
对比例1
提供市售的硅氧材料，作为对比例1的负极活性材料。
硅氧材料的成分组成如下：Li 8wt％、Si 52wt％、O 35.8wt％、C 4.2wt％。
实施例1
S1：提供与对比例1相同的硅氧材料作为基体。提供化学气相沉积(CVD)设备。将1kg基体置于化学气相沉积设备的反应腔内。用氮气吹扫反应腔，将反应腔升温至200℃
S2：以第一模式向反应腔通入混合气体，第一模式是指按照甲硅烷：乙炔：氮气＝20％：5％：75％的体积比例向反应腔通入混合气体，总气体流量为5L/min，并控制反应腔内压力高于大气压200Pa。
S3：将反应腔内温度升高至600℃，使甲硅烷与乙炔反应并使形成的反应产物(碳硅复合材料)沉积在基体上，沉积持续4h。
S4：以第二模式向反应腔通入混合气体，第二模式是指按照乙炔：氮气＝5％：95％的体积比向反应腔通入混合气体；
S5：将反应腔内温度升高至850℃，使乙炔分解形成碳材料并沉积在上一步产物的表面，沉积持续2h；
待产物冷却后从反应腔取出，过筛325目。得到实施例1的负极活性材料。
实施例1的负极活性材料包括基体，沉积在基体表面的第一包覆层，沉积在第一包覆层表面的第二包覆层。基体的材质为硅氧材料。第一包覆层的材质为硅碳复合材料。第二包覆层的材质为碳材料。
实施例2～3
实施例2与实施例1的区别在于：步骤S2：甲硅烷：乙炔：氮气＝20％：7％：73％。
实施例3与实施例1的区别在于：步骤S2：调整甲硅烷：乙炔：氮气＝20％：2％：78％。
对比例2～3
对比例2与实施例1的区别在于：步骤S2：甲硅烷：乙炔：氮气＝20％：10％：70％。
对比例3与实施例1的区别在于：步骤S2：甲硅烷：乙炔：氮气＝20％：0.5％：79.5％。
扣式电池的制备
采用对比例1和实施例1的负极活性材料组装为扣式锂离子电池，具体如下：
将负极活性物质、导电碳黑、粘结剂聚丙烯酸按质量比8:1:1混合后，加入溶剂去离子水，用搅拌机搅拌至体系呈均一状，获得固含量为45wt％的负极浆料。将负极浆料均匀涂覆在负极集流体铜箔上并在85℃下烘干，冷压后得到电极极片。以金属锂作为对电极，采用Celgard 2400隔离膜，并注入电解液，组装得到扣式电池。电解液的溶剂为碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)和碳酸二乙酯(DEC)的混合液，其中，EC、EMC和DEC的体积比为20:20:60。电解液的溶质为LiPF 6，浓度为1mol/L。电解液还含有添加剂氟代碳酸乙烯酯(FEC)，FEC在电解液中的含量为5wt％。
分析检测
粉体性能测试：
1)XPS检测
采用X射线光电子能谱仪(Thermo Scientific ESCALAB Xi+)对实施例和对比例的负极活性材料进行测试，得到材料的Si2p能谱。利用XPSpeak软件对Si2p能谱的特征峰进行分峰拟合处理。
对比例1的负极活性材料的Si2p能谱在100～104eV的范围具有一个特征峰，该特征峰的结合能为102.3eV，对应Si-O-C键的结合能。
图1示出实施例1的负极活性材料的Si2p能谱。如图1所示，实施例1的负极活性材料的Si2p能谱具有原始曲线100。原始曲线100在98～101eV和101～105eV各有一个特征峰。对在98～101eV的特征峰进行分峰拟合处理后能够形成拟合曲线200。拟合曲线200在101～105eV的位置表现为两个亚峰的叠加，两个亚峰包括：
结合能为99.7eV(对应Si-C键的结合能)的第一亚峰201；以及
结合能为98.9eV(对应Si-Si键的结合能)的第二亚峰202；
第一亚峰201的峰面积A Si-C与第二亚峰202的峰面积A Si-Si比值A Si-C/A Si-Si为1.7。第一亚峰与第二亚峰的峰强度均<2000。各实施例和对比例的A Si-C/A Si-Si测试结果如表2所示。
2)XRD测试、晶粒尺寸计算、激光衍射粒度分布
依据JIS K 0131-1996测试方法，采用Bruker D8 Discover X射线衍射仪测试得到上述硅碳材料的XRD谱图，测试角度范围20°-80°。获取数据后采用X’Pert Highscore plus软件进行拟合，并根据谢乐公式计算得到28.5°±0.1°对应的硅(1 1 1)晶面的晶粒大小。
实施例1和对比例1的XRD谱图如图2所示。对比例1的负极活性材料的XRD谱图中能够观察到Li 2SiO 3和Si的衍射峰。实施例1的负极活性材料的XRD谱图中衍射峰的分布与对比例基本一致，但衍射峰强度弱化。这说明实施例1在基体上沉积的硅碳复合材料和碳材料基本不具有衍射峰，基本呈非晶结构。
基于谢乐公式计算的硅晶粒尺寸如下表所示。对比例1和实施例1的负极活性材料中硅晶粒平均尺寸在6nm至8nm的范围内。
基于激光衍射法测得的实施例和对比例的负极活性材料的粒度分布数据如下表所示。其中包括体积分布粒度数据Dv10(μm)、Dv50(μm)、Dv90(μm)和Dv99(μm)，以及数量粒度分布数据D N10(μm)。粒度测试方法参考本领域通用的激光衍射法，例如GB/T 19077-2016粒度分布激光衍射法。实施例1和对比例1的负极活性材料的粒度分布数据如表1所示。
表1
  对比例1 实施例1
Dv10(μm) 3.8 4.3
Dv50(μm) 6.0 7.2
Dv90(μm) 9.3 12.1
Dv99(μm) 12.0 16.4
D N10(μm) 2.8 3.1
硅晶粒尺寸/谢乐公式计算 7.1 6.7
3)元素成分检测
按照以下测试方法对实施例1制备的负极活性材料进行元素成分检测
碳含量测试：依据GB/T 20123-2006/ISO 15350:2000测试标准，采用HSC-140碳含量分析仪测试得到材料碳含量。
锂、硅、氧元素含量测试：锂含量与硅含量通过电感耦合等离子体发射光谱仪(ICP，iICAP 7400设备)，依据标准EPA 6010D-2014进行测试测到，氧含量基于测试得到的碳含量/锂含量/硅含量进行计算，氧含量＝100％-硅含量-碳含量-锂含量。
实施例1的负极活性材料的成分组成如下：Li 6.8wt％、Si 57wt％、O 29.7wt％、C 6.5wt％。
实施例1的负极活性材料中，构成第一包覆层的硅碳复合材料的成分组成如下，硅含量97.5％，碳含量2.5％(根据沉积前后硅含量/碳含量进行计算)。各实施例和对比例的测试结果如表2所示。
4)电池首次充放电效率：
首周循环效率测试流程如下：
组装后的扣式电池静置60min。
嵌锂容量：先采用0.05C恒流放电至5mV，再采用50μA放电至5mV，静置10min。
脱锂容量：采用0.1C充电至1.5V。
首周嵌锂-脱锂的比容量-电压曲线如图3所示。
首周循环效率(简称首效)通过以下公式计算：
首效％＝脱锂容量/嵌锂容量
测试结果下表2所示。
由上表2和图3可知，与对比例1相比，实施例1的负极活性材料具有显著提高的脱锂容量和嵌锂容量。实施例1的负极活性材料的首效与对比例1基本相当。各实施例和对比例的测试结果如表2所示。
5)电池循环寿命检测：
将实施例和对比例的负极活性材料组装为全电池。
正极浆料配方如下：将正极NCM三元材料、导电剂Super P、粘结剂聚偏氟乙烯(PVDF)按质量比97:1.5:1.5进行混合，加入溶剂N-甲基吡咯烷酮(NMP)，在真空搅拌机作用下搅拌至体系呈均一状，获得固含量为77wt％的正极浆料。将正极浆料均匀涂覆于正极集流体铝箔上并在85℃下烘干，然后经过冷压、切边、分条、裁片，最后继续在85℃的真空条件下烘干4h，得到待用正极极片。
负极浆料配方如下：将负极活性物质(90％石墨、10％硅)、导电剂(含CNTs)、增稠剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶(SBR)按质量比96.2:1.3:1.0:1.5混合后，加入溶剂去离子水，在真空搅拌机作用下搅拌至体系呈均一状，获得固含量为52％的负极浆料；将负极浆料均匀涂覆在第一层负极膜层上并在85℃下烘干，然后经过冷压、切边、分条、裁片，最后继续在120℃的真空条件下烘干12h，得到待用负极极片。
电解液配方如下：有机溶剂为碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)和碳酸二乙酯(DEC)的混合液，其中，EC、EMC和DEC的体积比为20:20:60。在含水量<10ppm的氩气气氛手套箱中，将充分干燥的锂盐溶解于上述有机溶剂中，然后加入10wt％添加剂氟代碳酸乙烯酯(FEC)，混合均匀，获得电解液。其中，锂盐的浓度为1mol/L。
将正极浆料涂布于铝箔集流体得到正极极片，负极浆料涂布于铜箔集流体得到负极极片，将正极极片、隔膜、负极极片层叠卷绕后置于电池外壳内，注入电解液并密封，获得全电池。
对全电池进行充放电循环测试，充放电倍率为0.5C/1C，截止电压为2.5-4.25V，测试获得容量保持率-循环周数曲线，如图4所示。各实施例和对比例的200圈循环保持率测试结果如下表2所示
如表2和图4可知，实施例1和对比例1的全电池经200周循环后，容量保持率分别为96.6％和96.8％。实施例1与对比例1的容量保持率基本相当，实施例1的材料在显著提高比容量的同时，还保持了较好的容量保持率。
6)电芯能量密度测试
在25℃下，将实施例和对比例制备得到的电池以1C满放后，再以1C倍率满充、1C倍率满放，记录此时的实际放电能量；在25℃下，使用电子天平对该电池进行称重；电池1C实际放电能量D/Wh与电池重量m/kg的比值即为电池的实际能量密度E，E＝D/m。
实施例1和对比例1的全电池的能量密度分别为276Wh/kg和266Wh/kg，能量密度提升3.8％。各实施例和对比例的能量密度测试结果如下表2所示
Figure PCTCN2022092211-appb-000001
实施例1～3的负极活性材料的XPS Si2p谱图经分峰拟合后第一亚峰与第二亚峰的峰面积比值1～2：1。该负极活性材料用于二次电池，电池表现出提升的比容量、提升的首效，以及较好的循环寿命。
对比例3的负极活性材料的XPS Si2p谱图经分峰拟合后，第一亚峰与第二亚峰的峰面积比值<1，负极活性材料中纯硅含量高，硅晶粒较大，对寿命不利。对比例2的第一亚峰与第二亚峰的峰面积比值>2，负极活性材料中碳含量过高，导致活性材料的比容量较低，首效不佳。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (22)

  1. 一种负极活性材料，包括硅碳复合材料，所述硅碳复合材料的X射线光电子能谱(XPS)具有Si2p谱，所述Si2p谱具有至少一个特征峰，所述特征峰经分峰处理后能够形成以下亚峰，包括：
    结合能为99.5～99.9eV的第一亚峰；以及
    结合能为98.7～99.1eV的第二亚峰；
    所述第一亚峰与第二亚峰的峰面积比值为1～2：1。
  2. 根据权利要求1所述的负极活性材料，其具有以下一项或多项特征：
    (1)所述第一亚峰的结合能对应Si-C键的结合能；
    (2)所述第二亚峰是结合能对应Si-Si键的结合能；
    (3)第一亚峰的结合能为99.6～99.8eV；
    (4)第二亚峰的结合能为98.8～99.0eV；
    (5)第一亚峰与第二亚峰的峰面积比值为1.5～2：1；
    (6)硅碳复合材料中硅元素的含量为95wt％～99.9wt％，碳元素的含量为0.1wt％～5wt％。
  3. 根据权利要求1或2任一项所述的负极活性材料，所述负极活性材料包括基体和所述硅碳复合材料，所述硅碳复合材料附着在所述基体上。
  4. 根据权利要求3所述的负极活性材料，所述基体的具有多孔内部结构，所述硅碳复合材料附着在所述基体以下位置：
    所述基体的外表面；和/或
    所述多孔内部结构的孔隙中。
  5. 根据权利要求3或4任一项所述的负极活性材料，其中，所述基体的材质包括以下一项或多项：碳材料、硅氧材料、钛酸锂材料、或其组合。
  6. 根据权利要求1～5任一项所述的负极活性材料，所述负极活性材料还包括碳包覆层，所述碳包覆层覆盖所述基体和/或所述硅碳复合材料
  7. 根据权利要求6所述的负极活性材料，其中，所述碳材料包括以下一项或多项：石墨材料、硬碳材料、软碳材料、或其组合。
  8. 根据权利要求1～7任一项所述的负极活性材料，其中，所述硅碳复合材料含有硅晶粒，所述硅晶粒的晶粒尺寸为20nm以下。
  9. 根据权利要求1～8任一项所述的负极活性材料，其中，所述负极活性材料的体积中值粒径D V50为1～10μm。
  10. 根据权1～9任一项所述负极材料，其中，所述第一亚峰与第二亚峰的峰强度均<2000。
  11. 一种制备负极活性材料的方法，包括以下步骤：
    S1：提供基体和气相沉积设备，所述基体放置于沉积炉内，并预先用惰性气体吹扫且升温预热至200-300℃；
    S2：按第一模式向气相沉积设备内通入气体，所述第一模式包括向气相沉积设备同时通入硅源气体和碳源气体；
    S3：使硅源气体和碳源气体反应并使反应产物在基体上沉积，在基体上形成硅碳复合材料；
    所述硅碳复合材料的X射线光电子能谱(XPS)具有Si2p谱，所述Si2p谱具有至少一个特征峰，所述特征峰经分峰处理后能够形成以下亚峰，：
    结合能为99.5～99.9eV的第一亚峰；以及
    结合能为98.7～99.1eV的第二亚峰；
    所述第一亚峰与第二亚峰的峰面积比值为1～2：1。
  12. 根据权利要求11的方法，其中，步骤S2具有以下一项或多项特征：
    (1)所述硅源气体为甲硅烷、乙硅烷中的一种或多种；和/或，
    (2)所述碳源气体为甲烷、乙烯、乙炔中的一种或多种；
    (3)硅源气体与碳源气体的体积流量之比为2～10:1。
  13. 根据权利要求11～12任一项所述的方法，其中，步骤S2中所述第一模式包括向气相沉积设备同时通入硅源气体、碳源气体和惰性气体。
  14. 根据权利要求13所述的方法，其中，步骤S2具有以下一项或多项特征：
    (1)所述惰性气体为氮气、氩气中的一种或多种；
    (2)向气相沉积设备通入的惰性气体的流量占全部通入气体流量的30-85体积％。
  15. 根据权利要求11～14任一项所述的方法，其中，步骤S2中，按第一模式向气相沉积设备内通入气体，并保持设备内气压达到高于标准大气压的200～600Pa。
  16. 根据权利要求11～14任一项所述的方法，其中，步骤S3具有以下一项或多项特征：
    (1)步骤S3在400～800℃下进行；和/或，
    (2)步骤S3持续1～12小时。
  17. 根据权利要求10～15任一项所述的方法，其中，步骤S3之后还包括步骤S4：
    S4：在步骤S3的产物上沉积碳材料。
  18. 根据权利要求17所述的方法，其中，步骤S4包括以下操作：
    S4a：形成硅碳复合材料之后，按第二模式向气相沉积设备内通入气体，所述第二模式包括向气相沉积设备同时通入碳源气体和惰性气体，碳源气体占比为5％～15％，惰性气体占比为85％～95％；
    S4b：使碳源气体分解为碳材料并沉积在硅碳复合材料上。
  19. 根据权利要求18所述的方法，其中，操作S4b具有以下一项或多项特征：
    (1)步骤S4b在700～850℃进行；
    (2)步骤S4b持续1-6小时。
  20. 一种负极活性材料，由权利要求11～19任一项所述的方法制备获得。
  21. 一种二次电池，包括根据权利要求1-10、20中任一项所述的负极活性材料。
  22. 一种用电装置，包括根据权利要求21所述的二次电池。
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102637874A (zh) * 2012-04-11 2012-08-15 中国科学院过程工程研究所 一种锂离子电池硅碳复合负极材料及其制备方法
CN107170979A (zh) * 2017-06-12 2017-09-15 合肥国轩高科动力能源有限公司 一种用于锂离子电池负极材料的硅‑碳复合材料的制备方法
KR20200080490A (ko) * 2018-12-26 2020-07-07 울산과학기술원 음극활물질, 이의 제조방법 및 이를 포함하는 음극을 구비한 리튬 이차전지
CN112602210A (zh) * 2018-08-14 2021-04-02 Sj新材料有限公司 阴极活性物质、其制备方法以及具有包括所述阴极活性物质的阴极的锂二次电池

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102637874A (zh) * 2012-04-11 2012-08-15 中国科学院过程工程研究所 一种锂离子电池硅碳复合负极材料及其制备方法
CN107170979A (zh) * 2017-06-12 2017-09-15 合肥国轩高科动力能源有限公司 一种用于锂离子电池负极材料的硅‑碳复合材料的制备方法
CN112602210A (zh) * 2018-08-14 2021-04-02 Sj新材料有限公司 阴极活性物质、其制备方法以及具有包括所述阴极活性物质的阴极的锂二次电池
KR20200080490A (ko) * 2018-12-26 2020-07-07 울산과학기술원 음극활물질, 이의 제조방법 및 이를 포함하는 음극을 구비한 리튬 이차전지

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