WO2021068793A1 - 负极材料及其制备方法和应用以及含有其的锂离子电池 - Google Patents

负极材料及其制备方法和应用以及含有其的锂离子电池 Download PDF

Info

Publication number
WO2021068793A1
WO2021068793A1 PCT/CN2020/118704 CN2020118704W WO2021068793A1 WO 2021068793 A1 WO2021068793 A1 WO 2021068793A1 CN 2020118704 W CN2020118704 W CN 2020118704W WO 2021068793 A1 WO2021068793 A1 WO 2021068793A1
Authority
WO
WIPO (PCT)
Prior art keywords
negative electrode
electrode material
lithium
silicon
phosphorus
Prior art date
Application number
PCT/CN2020/118704
Other languages
English (en)
French (fr)
Inventor
孙赛
张丝雨
高焕新
Original Assignee
中国石油化工股份有限公司
中国石油化工股份有限公司上海石油化工研究院
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
Priority claimed from CN201910953233.6A external-priority patent/CN112635719B/zh
Priority claimed from CN201910953279.8A external-priority patent/CN112652755B/zh
Application filed by 中国石油化工股份有限公司, 中国石油化工股份有限公司上海石油化工研究院 filed Critical 中国石油化工股份有限公司
Priority to BR112022005774A priority Critical patent/BR112022005774A2/pt
Priority to AU2020363051A priority patent/AU2020363051A1/en
Priority to CN202080070424.9A priority patent/CN114467195B/zh
Priority to KR1020227015601A priority patent/KR20220078682A/ko
Priority to CA3157355A priority patent/CA3157355A1/en
Priority to EP20874623.0A priority patent/EP4044278A4/en
Priority to JP2022521414A priority patent/JP2022552485A/ja
Priority to US17/754,393 priority patent/US20220393152A1/en
Publication of WO2021068793A1 publication Critical patent/WO2021068793A1/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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—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
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—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
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present disclosure relates to the field of lithium-ion batteries. More specifically, the present disclosure relates to a silicon-based negative electrode material containing a phosphorus-containing coating layer, a preparation method thereof, and its application in a lithium ion battery, and also relates to a lithium ion battery containing the silicon-based negative electrode material.
  • the formation of irreversible SEI consumes a large amount of Li ions from the electrolyte and the cathode material. Therefore, the first coulombic efficiency (which can be referred to as "first effect") of silicon-based negative electrode materials is usually only between 65-85%. In addition, silicon's conductivity and lithium ion diffusion rate are lower than graphite, which will limit the performance of silicon under high current and high power conditions.
  • Nanometerization can reduce the volume deformation of silicon-based materials during charging and discharging, and significantly improve the cycle stability of the materials.
  • nano-sized silicon has a large specific surface area and is very easy to agglomerate, and cannot be uniformly distributed in the porous matrix, resulting in poor cycle stability and consistency of the material.
  • Coating refers to wrapping a protective layer of a certain thickness on the surface of the silicon material, which can not only relieve the volume expansion of silicon, but also inhibit the side reaction between the silicon material and the electrolyte, and improve the first-time coulombic efficiency and cycle stability of the material.
  • the commonly used coating methods are solid phase ball milling, spray coating, liquid coating and so on.
  • it is difficult to accurately control the thickness and uniformity of the coating layer obtained by the process.
  • the cycle stability of the material the reversible charging capacity and rate cycle stability performance of the material will be reduced to varying degrees. Alloying is an emerging modification process in recent years.
  • silicon is reacted with metal precursors such as aluminum, magnesium, and copper to prepare Si-Al, Si-Mg, and Si-Cu alloys, which can buffer volume expansion. , It can also increase the conductivity of silicon materials and improve certain electrical properties of the negative electrode material.
  • metal precursors such as aluminum, magnesium, and copper
  • Si-Al, Si-Mg, and Si-Cu alloys which can buffer volume expansion.
  • silicon alloys also have shortcomings such as low reversible charging capacity and sensitivity of some alloys to water and oxygen, and cannot meet commercial requirements in the short term. It can be seen that the current preparation process is difficult to completely solve the defects of poor cycle stability of silicon-based anodes, low first-time coulombic efficiency, and poor rate cycle stability.
  • CN108172775A reports a phosphorus-doped silicon-based negative electrode material.
  • the specific capacity of the phosphorus-doped silicon-based negative electrode in the example is 610.1 mAh/g, the first effect is 91.7%.
  • the CN108172775A preparation process requires spray drying, and the output is low-cost and high.
  • CN101179126B reports a doped silicon-based negative electrode material for lithium ion batteries.
  • the first effect of the silicon-based negative electrode material is improved by doping at least one element among boron, aluminum, gallium, antimony and phosphorus.
  • CN101179126B requires high-vacuum argon arc fusion welding during the preparation process, the reaction temperature is high (>1000°C), the reaction process is complicated (involving fusion welding, low-temperature blowing, rapid cooling, planetary ball milling and other operations), and the cost is relatively high.
  • CN103400971A reports a silicon carbon anode material doped with lithium silicate. Among them, when the addition amount of Si is 50% and the addition amount of Li2SiO3 is 35%, the specific capacity of the material is 1156.2mAh/g, and the first effect is 88.2%.
  • the present disclosure provides a silicon-based negative electrode material containing a phosphorus-containing coating layer, a preparation method of the negative electrode material, application of the negative electrode material in a lithium ion battery, and The anode material of the lithium ion battery.
  • the negative electrode material provided by the present disclosure has improved reversible charging capacity (also referred to as "reversible charging specific capacity") and first-time coulombic efficiency, and is particularly suitable for lithium ion batteries.
  • the present disclosure relates to a negative electrode material comprising a silicon-containing material and a phosphorus-containing coating layer on the periphery of the silicon-containing material, wherein the phosphorus-containing coating layer contains a condensed ring aromatic hydrocarbon The polymer of structural fragments.
  • the present disclosure relates to a method for preparing a negative electrode material, wherein the negative electrode material comprises a silicon-containing material and a phosphorus-containing coating layer on the periphery of the silicon-containing material, and the phosphorus-containing coating layer comprises A polymer of fused ring aromatic structural fragments, and the method includes:
  • the silicon-containing material, the phosphorus source and the solvent are brought into contact at 30-80°C, so that the phosphorus source is distributed on the periphery of the silicon-containing material;
  • the present disclosure relates to a negative electrode material prepared by the above method.
  • the present disclosure relates to the application of the above-mentioned negative electrode material in a lithium ion battery.
  • the present disclosure relates to a lithium ion battery including a negative electrode having the aforementioned negative electrode material, a positive electrode, a separator, and an electrolyte.
  • the present invention can be embodied as the following items:
  • a battery negative electrode material comprising a polymer lithium salt, a phosphorus source and an active component, the active component containing silicon.
  • the molecular chain of the polymer lithium salt has a -C(O)-OLi group
  • the polymer lithium salt is selected from at least one of lithium polyacrylate, lithium polymethacrylate, lithium polymaleate, lithium polyfumarate, lithium carboxymethyl cellulose, and lithium alginate.
  • the negative electrode material of item 1 or 2 wherein, based on the total amount of the negative electrode material, the content of the polymer lithium salt is 1-15% by weight, the content of the phosphorus source is 10-60% by weight, and the active group The content of fen is 25-75% by weight;
  • the content of the polymer lithium salt is 3-15% by weight
  • the content of the phosphorus source is 14-45% by weight
  • the content of the active component is 40-75% by weight.
  • the phosphorus source is polybasic phosphoric acid, more preferably phytic acid;
  • the phosphorus source is coated on the surface of the silicon element.
  • the conductive agent is selected from at least one of carbon nanotubes, acetylene black and conductive carbon black;
  • the content of the conductive agent is 1-10% by weight.
  • a preparation method of a battery negative electrode material comprising:
  • the phosphorus source is polyphosphoric acid, preferably phytic acid;
  • the solvent is an organic solvent, preferably at least one selected from toluene, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.
  • the mass ratio of the phosphorus source to the silicon source is 0.1-2:1, more preferably 0.5-1:1;
  • the solid content of the material obtained by mixing in step (1) is 5-40% by weight.
  • step (3) the mass ratio of the solid matter obtained by drying to the polymer lithium salt is 1: (0.03-0.15), preferably 1 : (0.08-0.13);
  • the weight average molecular weight of the polymer lithium salt is 2000-5000000, preferably 80,000-240,000;
  • the molecular chain of the polymer lithium salt has a -C(O)-OLi group
  • the polymer lithium salt is selected from at least one of lithium polyacrylate, lithium polymethacrylate, lithium polymaleate, lithium polyfumarate, lithium carboxymethyl cellulose, and lithium alginate;
  • the mixing in step (3) is carried out in the presence of water
  • the method further includes introducing a conductive agent in step (3);
  • the conductive agent is selected from at least one of carbon nanotubes, acetylene black and conductive carbon black;
  • the mass ratio of the solid substance obtained by drying to the conductive agent is 1: (0.01-0.12), preferably 1: (0.06-0.1).
  • the battery negative electrode material obtained by the preparation method of any one of items 6-9.
  • a lithium ion battery comprising the battery negative electrode material, positive electrode material, separator, and electrolyte according to any one of items 1 to 5 and 10;
  • the lithium ion battery is a liquid lithium ion battery, a semi-solid lithium ion battery or an all solid state lithium ion battery.
  • the anode material of the present disclosure has a phosphorus-containing coating layer. Under the high temperature of the temperature-programming process, some phosphorus elements can diffuse into the silicon to form occupancy doping, thereby improving the conductivity of the silicon-based anode material;
  • the phosphorus-containing coating layer of the present disclosure contains a polymer having a fused-ring aromatic structure segment, which means that the phosphorus-containing coating layer has a dense structure.
  • the dense structure of the coating layer can resist the volume expansion of the silicon-based negative electrode material that often occurs during the charge and discharge process, ensuring the structural integrity and safety of the battery.
  • the dense structure of the coating layer more effectively isolates the passage of lithium ions to the silicon-based negative electrode material, reduces and avoids the formation of irreversible SEI, and correspondingly alleviates and eliminates the electrical performance (e.g., first effect, The adverse effects of reversible charging capacity and cyclic charging capacity retention rate);
  • the phosphorus-containing coating layer of the present disclosure is obtained by high-temperature treatment.
  • the high temperature treatment will remove at least part of the polar groups on the surface of the coating layer. Therefore, on the one hand, although the anode material of the present disclosure has a small particle size, and the median particle size can even be in the nanometer range, it is not prone to agglomeration, and thus has excellent storage stability and dispersibility. In addition, the anode material of the present disclosure is more convenient for further surface modification, thereby having excellent workability.
  • Figure 1 shows a transmission electron microscope (TEM) image of the intermediate of the phosphorus-containing coating layer involved in Comparative Example 1 and Examples 1-3;
  • TEM transmission electron microscope
  • Example 2 shows a line scan distribution diagram of elements of the negative electrode material P1 obtained in Example 1;
  • Example 3 shows 13 C-NMR diagrams of the negative electrode material P1 obtained in Example 1 and the negative electrode material cP2 obtained in Comparative Example 2;
  • FIG. 7 shows a cycle stability test curve of a lithium ion battery using the negative electrode material P1 of Example 1;
  • Figure 8 shows a rate cycle stability test curve of a lithium ion battery using the negative electrode material cP2 of Comparative Example 2;
  • FIG. 9 shows the cycle stability test curve of a lithium ion battery using the negative electrode material cP2 of Comparative Example 2.
  • the median particle size (or D 50 ) refers to the particle size corresponding to when the cumulative particle size distribution percentage reaches 50%.
  • the median particle size is often used to indicate the average particle size of the powder.
  • the present disclosure relates to a negative electrode material comprising a silicon-containing material and a phosphorus-containing coating layer on the periphery of the silicon-containing material, wherein the phosphorus-containing coating layer contains a condensed ring aromatic hydrocarbon The polymer of structural fragments.
  • the thickness of the phosphorus-containing coating layer is very thin, and the thickness uniformity is high.
  • the thickness of the phosphorus-containing coating layer is 2-6 nanometers.
  • the silicon-containing material is selected from at least one of elemental silicon, SiOx and silicon-containing alloys, where 0.6 ⁇ x ⁇ 1.5.
  • the silicon-containing material is elemental silicon.
  • Elemental silicon is usually used in the form of silicon powder.
  • the median particle size of the silicon powder is 0.05-10 ⁇ m.
  • the silicon-containing material can be obtained commercially or can be prepared by a known method.
  • the silicon-containing alloy is selected from at least one of silicon-aluminum alloy, silicon-magnesium alloy, silicon-zirconium alloy, and silicon-boron alloy.
  • the content of silicon in the silicon-containing alloy is not particularly limited, and the selection range is relatively wide. For example, based on the total amount of the silicon-containing alloy, the content of silicon may be 10-50% by weight.
  • the preparation method of the silicon-containing alloy is also not particularly limited. For example, a method for preparing a silicon-aluminum alloy is provided herein. The method includes the following steps: 1) ball milling aluminum powder and silicon powder under the protection of an inert atmosphere for 30 minutes; and 2) heating the above mixture at 900°C High temperature treatment for 10h.
  • the polymer having fused ring aromatic structure fragments is formed from a phosphorus source selected from organic polybasic phosphoric acid and its esters or salts, preferably phytic acid.
  • the fused-ring aromatic structural fragments of the polymer having fused-ring aromatic structural fragments can be characterized by 13 C-NMR.
  • the 13 C-NMR spectrum of the polymer with fused ring aromatic structure fragments has a signal at the position of 110 ppm to 140 ppm, thereby showing the presence of the fused ring aromatic structure fragment.
  • 13 C-NMR spectra involving chemical shifts of fused ring aromatic hydrocarbons are disclosed in the following documents: Harris, KJ, Reeve ZEM, et al.
  • the phosphorus in the phosphorus-containing coating layer on the periphery of the silicon-containing material and the silicon in the silicon-containing material are connected by a chemical bond, preferably the chemical bond is P(O)-O-Si.
  • the chemical bond is P(O)-O-Si.
  • the connection of phosphorus and silicon through P(O)-O-Si can be characterized by 29 Si-NMR spectroscopy.
  • the negative electrode material may further include a carbon layer located on the outer periphery of the phosphorus-containing coating layer.
  • the carbon layer may form an outer shell of the negative electrode material, in which a silicon-containing material and a phosphorous-containing coating layer on the periphery of the silicon-containing material are contained.
  • the carbon layer may have a porous structure. The pore size distribution of the porous structure is not particularly limited.
  • the negative electrode material may further comprise a polymer lithium salt, preferably the polymer lithium salt has a -C(O)-OLi group on the molecular chain. This group can be obtained by the characterization of total reflection Fourier transform absorption infrared spectroscopy.
  • the introduction of polymer lithium salt into the negative electrode material can compensate the lithium lost during the charge and discharge process of the negative electrode material, thereby improving the reversible charge capacity and first effect of the negative electrode material.
  • the polymer lithium salt is preferably at least one selected from the group consisting of lithium polyacrylate, lithium polymethacrylate, lithium polymaleate, lithium polyfumarate, lithium carboxymethyl cellulose, and lithium alginate.
  • the molecular weight of the polymer lithium salt is not particularly limited, and the selection range is wide.
  • the weight average molecular weight of the polymer lithium salt is 2000-5000000, preferably 80,000-240,000.
  • the polymer lithium salt can be obtained commercially or can be prepared by a known method.
  • the lithium polyacrylate can be obtained by reacting polyacrylic acid and a lithium source (preferably lithium hydroxide) in the presence of a solvent (for example, water).
  • the lithium polymethacrylate can be obtained by reacting polymethacrylic acid and a lithium source (preferably lithium hydroxide) in the presence of a solvent (for example, water).
  • the lithium polymaleate can be obtained by reacting polymaleic acid with a lithium source (preferably lithium hydroxide) in the presence of a solvent (for example, water).
  • the polylithium fumarate can be obtained by reacting polyfumaric acid and a lithium source (preferably lithium hydroxide) in the presence of a solvent (for example, water).
  • the carboxymethyl cellulose lithium can be reacted by carboxymethyl cellulose and/or its salt (for example, sodium salt) and a lithium source (preferably lithium hydroxide and/or lithium oxide) in the presence of a solvent (for example, water) get.
  • the lithium alginate can be obtained by reacting alginic acid and/or its salt (for example, sodium salt) and a lithium source (preferably lithium hydroxide and/or lithium oxide) in the presence of a solvent (for example, water).
  • the specific reaction process can be carried out in accordance with conventional reactions in the field, and will not be repeated here.
  • the polymer lithium salt may be contained in the phosphorus-containing coating layer, or may be contained in the carbon layer.
  • the polymer lithium salt is contained in the carbon layer, and more preferably, at least a part of the lithium ion intercalation layer of the polymer lithium salt is in the porous carbon layer.
  • the content of the polymer lithium salt in the negative electrode material is not particularly limited, and the selection range is relatively wide.
  • the content of the polymer lithium salt is 0-34% by weight, more preferably 10-30% by weight.
  • the negative electrode material further includes graphite.
  • graphite Although the theoretical capacity of carbon is much lower than that of silicon, the introduction of graphite into the negative electrode material can compensate for the lower conductivity of silicon, and can also greatly improve the cycle charge capacity retention rate. The use of graphite also does not have the problem of volume expansion experienced by silicon anode materials during charging and discharging.
  • the negative electrode material further includes a conductive agent.
  • the conductive agent is preferably at least one selected from carbon nanotubes, acetylene black, and conductive carbon black.
  • the carbon nanotubes, acetylene black and conductive carbon black have meanings conventionally understood by those skilled in the art, and are commercially available.
  • the content of the conductive agent is 1-10% by weight, more preferably 1-6% by weight.
  • the anode material of the present disclosure is in the form of particles.
  • the negative electrode material When graphite is not incorporated in the negative electrode material, the negative electrode material has a small median particle size (D50), generally 0.1-20 microns, and has a narrower particle size distribution.
  • the negative electrode material is in the form of nanoparticles.
  • the nanometerization of the anode material further improves the overall electrical performance.
  • the size of the negative electrode material increases.
  • the median particle size of the negative electrode material can be 1-25 microns.
  • the present disclosure relates to a method of preparing a negative electrode material, wherein the negative electrode material comprises a silicon-containing material and a phosphorus-containing coating layer on the periphery of the silicon-containing material, and the phosphorus-containing coating layer comprises a dense Cyclic aromatic hydrocarbon structural fragments, and the method includes:
  • the silicon-containing material, the phosphorus source and the solvent are brought into contact at 30-80°C, so that the phosphorus source is distributed on the periphery of the silicon-containing material;
  • the phosphorus source is any phosphorus-containing precursor that can be converted into a polymer containing fused ring aromatic structural fragments, for example, by polycondensation.
  • the phosphorus source is selected from organic polybasic phosphoric acid and its esters or salts, preferably phytic acid.
  • the mass ratio of the phosphorus source and the silicon-containing material is 0.1-2:1, preferably 0.5-1:1. You can select any value in this range, for example, 0.1:1, 0.5:1, 1:1, 1.5:1, 2:1.
  • the solvent used in step (1) may be an organic solvent conventionally used in the art, preferably at least one of toluene, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone One kind.
  • the amount of solvent added is such that the solid content of the material in step (1) is 5-40% by weight, preferably 5-30% by weight.
  • Step (1) can be carried out by the following operations: first mix the phosphorus source and the solvent, then add the silicon-containing material, raise the temperature to 30-80°C and leave for 0.5-4 hours; or first mix the silicon-containing material and the solvent, and then add the phosphorus Source, heat up to 30-80°C and keep it for 0.5-4 hours.
  • the phosphorus source and the solvent are mixed first, and then the silicon-containing material is added, and the temperature is raised to 30-80° C. and kept for 1-4 hours.
  • step (1) the phosphorus source is uniformly distributed on the outer periphery of the silicon-containing material to form an intermediate of the phosphorus-containing coating layer.
  • elevated temperature for example, 30-80°C
  • the thickness of the intermediate of the phosphorus-containing coating layer obtained is reduced, and the thickness uniformity is higher.
  • the thickness of the intermediate of the phosphorus-containing coating layer is 3-15 nanometers, preferably 4-10 nanometers.
  • the temperature is increased to a first temperature of 450-500°C, for example, 480°C, at a first temperature rise rate of 1-10°C/min, preferably 5-10°C/min;
  • the second temperature rise rate of 5°C/min, preferably 1-3°C/min is increased to a second temperature of 600-650°C, such as 620°C; the temperature is maintained at the second temperature for 1-8h, preferably 2-4h.
  • the phosphorous source can be converted into polymers containing fused-ring aromatic structural fragments.
  • high-temperature operation also promotes the doping of phosphorus into silicon and removes at least part of the polar groups on the surface of the coating layer (for example, by removing phosphate groups).
  • the inventor believes that phosphorus-doped silicon improves the conductivity of the silicon-based negative electrode material.
  • the polymer with the fused ring aromatic structure segment imparts a dense structure to the phosphorus-containing coating layer.
  • the silicon-based negative electrode material can resist the volume expansion that often occurs during the charge and discharge process, and ensure the structural integrity and safety of the battery.
  • the dense structure of the coating layer more effectively isolates the passage of lithium ions from approaching the silicon-based negative electrode material, reduces and avoids the formation of irreversible SEI, and correspondingly alleviates and eliminates the adverse effects on electrical performance.
  • the high temperature operation also removes at least part of the polar groups on the surface of the coating layer, so that the resulting negative electrode material has excellent storage stability, dispersibility and processability.
  • the present disclosure relates to a negative electrode material prepared by the above method.
  • the present disclosure relates to the application of the above-mentioned negative electrode material in a lithium ion battery.
  • the above-mentioned anode materials Compared with traditional pure graphite anode materials, the above-mentioned anode materials contain silicon with a higher theoretical capacity, so that the reversible charging specific capacity is significantly increased. Therefore, when the above-mentioned anode materials are used in lithium-ion batteries, the energy density of lithium batteries can be increased. .
  • the present disclosure relates to a lithium ion battery including a negative electrode having the aforementioned negative electrode material, a positive electrode, a separator, and an electrolyte.
  • the lithium ion battery according to the embodiment of the present disclosure has a structure known to those skilled in the art.
  • the separator is located between the positive electrode and the negative electrode.
  • the positive electrode contains a positive electrode material.
  • the specific composition of the positive electrode material is not particularly limited, and it may be a lithium-based positive electrode material conventionally used in the field.
  • the separator can be various separators commonly used in lithium ion batteries, such as polypropylene microporous membrane, polyethylene felt, glass fiber felt or ultra-fine glass fiber paper.
  • the electrolyte may be various conventional electrolytes, such as non-aqueous electrolytes.
  • the non-aqueous electrolyte is a solution of electrolyte lithium salt in a non-aqueous solvent.
  • the lithium salt suitable for forming a non-aqueous electrolyte can be selected from lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6) and lithium hexafluorosilicate (LiSiF6) At least one of them.
  • Suitable non-aqueous solvents can be selected from linear acid esters and cyclic acid esters and mixtures thereof, wherein the linear acid esters can be dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC ), at least one of methyl propyl carbonate (MPC) and dipropyl carbonate (DPC).
  • the cyclic acid ester may be at least one of ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC).
  • the morphology of the sample was characterized by a transmission electron microscope.
  • the transmission electron microscope is a transmission electron microscope model JEM-2100 manufactured by JEOL Ltd., and the test condition is: an acceleration voltage of 160KV.
  • an electron microscope is inserted for observation, and a magnification of 800,000 times is used for the observation.
  • the spherical aberration transmission electron microscope was used to characterize the elements in the material coating layer.
  • the transmission electron microscope is a Titan Cubed Themis G2 300 transmission electron microscope from FEI Company of the United States, and the test conditions are: accelerating voltage of 300 KV, HAADF detector collecting signals, and receiving angle of 52-200 mrad.
  • the sample is placed on the ultra-thin carbon film for observation, and the component analysis of the sample is completed by the X-ray energy spectrometer (Aztec X-max 100TLE) equipped with the electron microscope.
  • JNMR-500 solid-state nuclear magnetic resonance spectrometer was used to characterize the microstructure of the material. Test conditions: 8mm zirconium dioxide rotor, rotating speed 5000-6000. The resonance frequency of 13 C is 125.72 MHz, and the chemical shift reference value is tetramethylsilane. It adopts a high-power decoupling and cross-polarization test scheme, and the number of scans is 5000 times.
  • JNMR-500 solid-state nuclear magnetic resonance spectrometer was used to characterize the microstructure of the material. Test conditions: 8mm zirconium dioxide rotor, rotating speed 5000-6000. The resonance frequency of 29 Si is 79.49 MHz, and the chemical shift reference value is tetramethylsilane. It adopts a high-power decoupling and cross-polarization test scheme, and the number of scans is 5000 times.
  • the prepared negative electrode material was assembled into a lithium ion battery sample, and the electrochemical performance of the obtained lithium ion battery sample was tested using the Wuhan blue battery test system (CT2001B). Test conditions include: voltage range 0.05V-2V. For each negative electrode material, 10 samples in the form of button batteries were assembled. Test the battery performance of the sample under the same voltage and current, and take the average value as the measured value.
  • C2001B Wuhan blue battery test system
  • the battery test system (CT2001B) will give the first discharge capacity and the first charge capacity of the test battery.
  • the first discharge capacity is the specific capacity of the negative electrode material
  • the first charge capacity is the reversible charging specific capacity of the negative electrode material.
  • the first Coulomb efficiency (referred to as "first effect") can be calculated through the two:
  • the first Coulomb efficiency the reversible charging specific capacity of the negative electrode material/the specific capacity of the negative electrode material.
  • the assembled lithium-ion battery sample is subjected to a selected number of times, such as 20, 50, or 100 charge and discharge cycles, and the reversible charging specific capacity of the sample at each cycle is measured, and each cycle is calculated from this
  • the cyclic charge capacity retention rate where:
  • Cycle charge capacity retention rate reversible charge specific capacity under the corresponding cycle number/reversible charge specific capacity at the first charge ⁇ 100%
  • the cycle charge capacity retention rate of the negative electrode material is positively correlated with its conductivity. That is to say, the better the conductivity of the negative electrode material, the higher the cycle charge capacity retention rate under the same rate. Therefore, the rate cycle stability can be used to reflect the conductivity of the negative electrode material.
  • Lithium polyacrylate is obtained by self-preparation. Specifically, 10 g of polyacrylic acid with a weight average molecular weight of 240,000 was added to 40 g of deionized water to prepare a polyacrylic acid solution with a mass fraction of 20%. Weigh 3.4 g of lithium hydroxide, add it to the polyacrylic acid solution, heat and stir at 40°C until all solids are dissolved, and dry at 100°C for 4 hours to obtain lithium polyacrylate.
  • the boundary of the intermediate of the phosphorus-containing coating layer is drawn, as shown by the curve in Fig. 1(b).
  • the thickness of the intermediate of the phosphorus-containing coating layer is basically uniform, which is consistent with the data given by the transmission electron microscope test.
  • the temperature was increased to 480°C at a first heating rate of 5°C/min, and then to 620°C at a second heating rate of 2°C/min, and kept at 620°C for 3 hours.
  • negative electrode material P1 After cooling to room temperature, a product is obtained, which is called negative electrode material P1.
  • the negative electrode material P1 is sampled, and the element line scan test is performed as described above to obtain the element line scan distribution map of the material, and the result is shown in FIG. 2.
  • the content of silicon gradually decreases, and the content of phosphorus peaks in the range of 15-18.7nm. It can be seen that the phosphorus-containing coating layer is formed on the periphery of the silicon, and its thickness is 3.7 nm.
  • the lithium ion battery sample for the electrical performance test of the negative electrode material was prepared as follows: 1g of the obtained negative electrode material P1 was taken, formed into a slurry and uniformly coated on the copper foil current collector, and dried at 120°C for 10 hours to obtain the negative electrode material
  • the negative pole of P1 is N1.
  • the negative electrode N1, the metal lithium sheet as the positive electrode, and the 1mol/L LiPF 6 solution as the electrolyte (wherein, the mixture of ethylene carbonate and diethyl carbonate in a volume ratio of 3:7 is used as the solvent), as the polymer of the separator Propylene microporous membrane, assembled into CR2016 button battery.
  • FIG. 5 is a first charge and discharge curve of a coin battery based on the negative electrode material P1 of Example 1.
  • the first discharge capacity (specific capacity) of the negative electrode material P1 of Example 1 is 3858 mAh/g
  • the first charge capacity (reversible charge specific capacity) is 3442 mAh/g
  • the corresponding first coulombic efficiency is 89.2%.
  • FIG. 6 is a test curve of rate cycle stability of a coin battery based on the negative electrode material P1 of Example 1.
  • FIG. It can be seen from Figure 6 that the negative electrode material P1 of Example 1 has a cycle charge capacity retention rate of 100%, 92%, 81%, and 63% at 1/3C, 1/2C, 1C, 2C, 3C, and 5C magnifications. , 37% and 6%.
  • FIG. 7 is a cycle stability test curve of a coin battery based on the negative electrode material P1 of Example 1.
  • the boundary of the intermediate of the phosphorus-containing coating layer is drawn, as shown by the curve in FIG. 1(c).
  • the thickness of the intermediate of the phosphorus-containing coating layer is basically uniform, which is consistent with the data given by the transmission electron microscope test.
  • the temperature is increased to 500°C at a first heating rate of 8°C/min, and then to 650°C at a second heating rate of 3°C/min, and the temperature is maintained at 650°C for 2 hours.
  • negative electrode material P2 After cooling to room temperature, a product is obtained, which is called negative electrode material P2.
  • the negative electrode material P2 is sampled, and the element line scan test is performed as described above, and the obtained element line scan distribution diagram is similar to FIG. 2.
  • the 13 C-NMR chart of the sample is similar to the upper graph in FIG. 3.
  • the 29 Si-NMR chart of the sample is similar to Fig. 4. Therefore, the negative electrode material P2 has a morphology similar to that of the negative electrode material P1.
  • the negative electrode material P2 was used instead of the negative electrode material P1, and the lithium ion battery sample for the electrical performance test of the negative electrode material was prepared by repeating the method described in Example 1.
  • the test results show that the reversible charging capacity of the negative electrode material P2 of Example 2 is 3208 mAh/g, and the first coulombic efficiency is 87.8%.
  • the cycle charge capacity retention rate was 87.4%.
  • the temperature is increased to 450°C at a first heating rate of 10°C/min, and then to 600°C at a second heating rate of 3°C/min, and the temperature is kept at 600°C for 4 hours.
  • negative electrode material P3 After cooling to room temperature, the product is obtained, which is called negative electrode material P3.
  • the negative electrode material P3 is sampled, and the element line scan test is performed as described above, and the obtained element line scan distribution diagram is similar to FIG. 2.
  • the 13 C-NMR chart of the sample is similar to the upper graph in FIG. 3.
  • the 29 Si-NMR chart of the sample is similar to Fig. 4. Therefore, the negative electrode material P3 has a morphology similar to that of the negative electrode material P1.
  • the negative electrode material P3 was used to replace the negative electrode material P1, and the lithium ion battery sample for the electrical performance test of the negative electrode material was prepared by repeating the method described in Example 1.
  • the test results show that the reversible charging capacity of the negative electrode material P3 of Example 3 is 3119 mAh/g, and the first coulombic efficiency is 87.5%.
  • the negative electrode material P3 of Example 3 has a charge-discharge rate of 0.2C, and after 100 cycles, the cycle charge capacity retention rate is 87.9%.
  • the boundary of the intermediate of the phosphorus-containing coating layer is drawn by distinguishing the lattice fringes and the texture texture of the amorphous structure in the TEM, as shown by the curve in FIG. 1(a).
  • the thickness of the intermediate of the phosphorus-containing coating layer is not uniform, which is consistent with the data given by the transmission electron microscope test.
  • the temperature was increased to 480°C at a first heating rate of 5°C/min, and then to 620°C at a second heating rate of 2°C/min, and kept at 620°C for 3 hours.
  • negative electrode material cP1 After cooling to room temperature, the product is obtained, which is called negative electrode material cP1.
  • the negative electrode material cP1 was used to replace the negative electrode material P1, and the lithium ion battery sample for the electrical performance test of the negative electrode material was prepared by repeating the method described in Example 1.
  • the test results show that the reversible charging capacity of the negative electrode material cP1 of Comparative Example 1 is 2820 mAh/g, and the first coulombic efficiency is 84.3%.
  • the negative electrode material cP1 of Comparative Example 1 has a charge-discharge rate of 0.2C. After 100 cycles, the cycle charge capacity retention rate is 65.9%.
  • negative electrode material cP2 After cooling to room temperature, the product is obtained, which is called negative electrode material cP2.
  • the full text is incorporated as a reference.
  • the negative electrode material cP2 was used to replace the negative electrode material P1, and the lithium ion battery sample for the electrical performance test of the negative electrode material was prepared by repeating the method described in Example 1.
  • the test results show that the reversible charging capacity of the negative electrode material cP2 of Comparative Example 2 is 2621 mAh/g, and the first coulombic efficiency is 80.6%.
  • FIG. 8 is a test curve of rate cycling stability of a coin cell based on the negative electrode material cP2 of Comparative Example 2.
  • FIG. The negative electrode material cP2 of Comparative Example 2 has a retention rate of 70%, 60%, 20%, 5%, 3%, and 1% at magnifications of 1/3C, 1/2C, 1C, 2C, 3C, and 5C, respectively.
  • FIG. 9 is a cycle stability test curve of a coin battery based on the negative electrode material cP2 of Comparative Example 2.
  • FIG. 9 the negative electrode material cP2 of Comparative Example 2 has a charge-discharge rate of 0.2C, and after 100 cycles, the cycle charge capacity retention rate is less than 18.9%.
  • the negative electrode material P1 of Example 1 and graphite were blended in a mass ratio of 10:1 to obtain the negative electrode material P4.
  • the negative electrode material P4 was sampled, and the transmission electron microscope test was performed as described above. The test results show that graphite is distributed on the outer surface.
  • the negative electrode material P4 was used to replace the negative electrode material P1, and the lithium ion battery sample for the electrical performance test of the negative electrode material was prepared by repeating the method described in Example 1.
  • the test results show that the reversible charging capacity of the negative electrode material P4 of Example 4 is 552 mAh/g, and the first coulombic efficiency is 88.5%.
  • the cycle charge capacity retention rate was 89.2%.
  • the negative electrode material P1 of Example 1 and lithium polyacrylate were blended in a mass ratio of 10:1 to obtain the negative electrode material P4.
  • the negative electrode material P5 was substituted for the negative electrode material P1, and the lithium ion battery sample for the electrical performance test of the negative electrode material was prepared by repeating the method described in Example 1.
  • the test results show that the reversible charging capacity of the negative electrode material P5 of Example 5 is 3289 mAh/g, and the first coulombic efficiency is 90.5%.
  • the cycle charge capacity retention rate was 85.5%.
  • the negative electrode material P6 was used to replace the negative electrode material P1, and the lithium ion battery sample for the electrical performance test of the negative electrode material was prepared by repeating the method described in Example 1.
  • the test results show that the reversible charging capacity of the negative electrode material P6 of Example 6 is 3552 mAh/g, and the first coulombic efficiency is 91.3%.
  • the cycle charge capacity retention rate was 90.4%.
  • the surface of the nano-silicon powder is coated with a layer of phosphorus-containing material, forming a "core-shell" structure.
  • the P element and Si element in the material are combined through P(O)-O-Si.
  • the above chemical bond can ensure that the coating shell can exist stably without being affected by the outside world.
  • the environmental impact lays the foundation for the excellent electrical properties of the material.
  • step 5 Take 1 g of the lithium-containing negative electrode material S-1 slurry obtained in step 4) and uniformly coat it on the copper foil current collector, and dry it at 120° C. for 10 hours to obtain the lithium-containing negative electrode material S-1 pole piece.
  • the porous membrane is a separator and assembled into a CR2016 button battery to characterize the electrical properties of the lithium-containing negative electrode material S-1 described in the examples.
  • the first charge-discharge curve (test voltage range 0.05-3V, current 50mA) of the button battery based on the lithium-containing negative electrode material S-1 is obtained.
  • the test result shows that the reversible charging capacity of the lithium-containing negative electrode material S-1 is 3000 mAh/g, and the first coulombic efficiency is 86.9%.
  • the TEM image and X-ray photoelectron spectrogram of the phosphorus-containing silicon powder are similar to those of the phosphorus-containing silicon powder described in Example 7, respectively.
  • step 5) Take 1 g of the lithium-containing negative electrode material S-2 slurry obtained in step 4) and uniformly coat it on a copper foil current collector, and dry it at 120° C. for 10 hours to obtain a pole piece of lithium-containing negative electrode material S-2.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the lithium-containing negative electrode material S-2.
  • the test results show that the reversible charging capacity of the lithium-containing negative electrode material S-2 is 2720 mAh/g, and the first coulombic efficiency is 85.2%.
  • the TEM image and X-ray photoelectron spectrogram of the phosphorus-containing silicon powder are similar to those of the phosphorus-containing silicon powder described in Example 7, respectively.
  • step 5 Take 1.5 g of the slurry of lithium-containing negative electrode material S-3 obtained in step 4) and uniformly coat it on a copper foil current collector, and dry it at 120° C. for 10 hours to obtain a pole piece of lithium-containing negative electrode material S-3.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the lithium-containing negative electrode material S-3.
  • the test results show that the reversible charging capacity of the lithium-containing negative electrode material S-3 is 2978mAh/g, and the first coulombic efficiency is 86.1%.
  • the TEM image and X-ray photoelectron spectrogram of the phosphorus-containing silicon powder are similar to those of the phosphorus-containing silicon powder described in Example 7, respectively.
  • step 5 Take 1.5 g of the lithium-containing negative electrode material S-4 slurry obtained in step 4) and uniformly coat it on a copper foil current collector, and dry at 120° C. for 10 hours to obtain a pole piece of lithium-containing negative electrode material S-4.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the lithium-containing negative electrode material S-4.
  • the test result shows that the reversible charging capacity of the lithium-containing negative electrode material S-4 is 2650 mAh/g, and the first coulombic efficiency is 83.1%.
  • the TEM image and X-ray photoelectron spectrogram of the phosphorus-containing silicon oxide powder are similar to those of the phosphorus-containing silicon powder described in Example 7, respectively.
  • step 5 Take 1.2 g of the lithium-containing negative electrode material S-5 slurry obtained in step 4) and uniformly coat it on a copper foil current collector, and dry it at 120° C. for 10 hours to obtain a lithium-containing negative electrode material S-5 pole piece.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the lithium-containing negative electrode material S-5.
  • the test result shows that the reversible charging capacity of the lithium-containing negative electrode material S-5 is 1650 mAh/g, and the first coulombic efficiency is 73.5%.
  • the TEM image and X-ray photoelectron spectrogram of the phosphorus-containing silicon powder are similar to those of the phosphorus-containing silicon powder described in Example 7, respectively.
  • step 5 Take 1.2 g of the lithium-containing negative electrode material S-6 slurry obtained in step 4) and uniformly coat it on a copper foil current collector, and dry at 120°C for 10 hours to obtain a pole piece of lithium-containing negative electrode material S-6.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the lithium-containing negative electrode material S-6.
  • the test result shows that the reversible charging capacity of the lithium-containing negative electrode material S-6 is 3120 mAh/g, and the first coulombic efficiency is 87.2%.
  • the TEM image and X-ray photoelectron spectrogram of the phosphorus-containing silicon oxide powder are similar to those of the phosphorus-containing silicon powder described in Example 7, respectively.
  • step 5 Take 1.2 g of the lithium-containing negative electrode material S-7 slurry obtained in step 4) and uniformly coat it on a copper foil current collector, and dry at 120° C. for 10 hours to obtain a pole piece of lithium-containing negative electrode material S-7.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the lithium-containing negative electrode material S-7.
  • the test results show that the reversible charging capacity of the lithium-containing negative electrode material S-7 is 1810 mAh/g, and the first coulombic efficiency is 80.1%.
  • the TEM image and X-ray photoelectron spectrogram of the phosphorus-containing silicon powder are similar to those of the phosphorus-containing silicon powder described in Example 7, respectively.
  • step 5 Take 1 g of the lithium-containing negative electrode material S-8 slurry obtained in step 4) and uniformly coat it on a copper foil current collector, and dry it at 120° C. for 10 hours to obtain a lithium-containing negative electrode material S-8 pole piece.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the lithium-containing negative electrode material S-8.
  • the test result shows that the reversible charging capacity of the lithium-containing negative electrode material S-8 is 2950 mAh/g, and the first coulombic efficiency is 86.1%.
  • the TEM image and X-ray photoelectron spectrogram of the phosphorus-containing silicon powder are similar to those of the phosphorus-containing silicon powder described in Example 7, respectively.
  • step 5 Take 1 g of the lithium-containing negative electrode material S-9 slurry obtained in step 4) and uniformly coat it on a copper foil current collector, and dry it at 120° C. for 10 hours to obtain a pole piece of lithium-containing negative electrode material S-9.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the lithium-containing negative electrode material S-9.
  • the test result shows that the reversible charging capacity of the lithium-containing negative electrode material S-9 is 2760 mAh/g, and the first coulombic efficiency is 83.5%.
  • the TEM image and X-ray photoelectron spectrogram of the phosphorus-containing silicon powder are similar to those of the phosphorus-containing silicon powder described in Example 7, respectively.
  • step 5 Take 1.5 g of the lithium-containing negative electrode material S-10 slurry obtained in step 4) and uniformly coat it on a copper foil current collector, and dry it at 120° C. for 10 hours to obtain a lithium-containing negative electrode material S-10 pole piece.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the lithium-containing negative electrode material S-10.
  • the test results show that the reversible charging capacity of the lithium-containing negative electrode material S-10 described in 10 is 2632 mAh/g, and the first coulombic efficiency is 81.4%.
  • the TEM image and X-ray photoelectron spectrogram of the phosphorus-containing silicon powder are similar to those of the phosphorus-containing silicon powder described in Example 7, respectively.
  • step 5 Take 1.5 g of the slurry of lithium-containing negative electrode material S-11 obtained in step 4) and uniformly coat it on a copper foil current collector, and dry it at 120° C. for 10 hours to obtain a pole piece of lithium-containing negative electrode material S-11.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the lithium-containing negative electrode material S-11.
  • the test result shows that the reversible charging capacity of the lithium-containing negative electrode material S-11 is 2753 mAh/g, and the first coulombic efficiency is 83.6%.
  • the TEM image and X-ray photoelectron spectrogram of the phosphorus-containing silicon powder are similar to those of the phosphorus-containing silicon powder described in Example 7, respectively.
  • step 5 Take 1.5 g of the lithium-containing negative electrode material S-12 slurry obtained in step 4) and uniformly coat it on a copper foil current collector, and dry at 120° C. for 10 hours to obtain a pole piece of lithium-containing negative electrode material S-12.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the lithium-containing negative electrode material S-12.
  • the test result shows that the reversible charging capacity of the lithium-containing negative electrode material S-12 is 2695 mAh/g, and the first coulombic efficiency is 82.1%.
  • the TEM image and X-ray photoelectron spectrogram of the phosphorus-containing silicon powder are similar to those of the phosphorus-containing silicon powder described in Example 7, respectively.
  • step 5 Take 1.5 g of the lithium-containing negative electrode material S-13 slurry obtained in step 4) and uniformly coat it on a copper foil current collector, and dry at 120°C for 10 hours to obtain a pole piece of lithium-containing negative electrode material S-13.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the lithium-containing negative electrode material S-13.
  • the test result shows that the reversible charging capacity of the lithium-containing negative electrode material S-13 is 2710 mAh/g, and the first coulombic efficiency is 82.5%.
  • the negative electrode material D-1 was prepared according to the method of Example 7, except that step 3) of Comparative Example 1 did not add 3.4 g of lithium hydroxide.
  • the content of each component of the negative electrode material D-1 is shown in Table 1.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the negative electrode material D-1.
  • the first charge and discharge curve of the coin battery based on the negative electrode material D-1 is obtained.
  • the reversible charging capacity of the negative electrode material D-1 is 908 mAh/g, and the first coulombic efficiency is 38.9%.
  • the difference is that no phosphorus source is added during the preparation of the negative electrode material. specifically:
  • 1g of the slurry of the lithium-containing negative electrode material D-2 was uniformly coated on a copper foil current collector, and dried at 120° C. for 10 hours to obtain a pole piece of the lithium-containing negative electrode material D-2.
  • the battery was assembled and the electrical performance test was performed according to the method of Example 7, except that the pole piece of the lithium-containing negative electrode material S-1 was replaced with the pole piece made of the lithium-containing negative electrode material D-2.
  • the test result shows that the reversible charging capacity of the lithium-containing negative electrode material D-2 is 1650 mAh/g, and the first coulombic efficiency is 83.5%.
  • the negative electrode material according to the embodiment of the present disclosure when used in a lithium-ion battery, has the advantages of reversible charge capacity, first coulombic efficiency, and cycle charge capacity retention rate , Especially in the charge retention rate of the longer cycle period has been improved.

Landscapes

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

Abstract

本公开涉及硅基负极材料及其制备方法和其在锂离子电池中的应用，还涉及包含该硅基负极材料的锂离子电池。本公开的负极材料包含含硅材料和在所述含硅材料外周的含磷包覆层，其中所述含磷包覆层包含具有稠环芳烃结构片段的聚合物。本公开的负极材料同时具有改善的首次库伦效率、可逆充电比容量、循环充电容量保留率和导电性。在用于锂离子电池中时，本公开的负极材料可以提高锂电池的能量密度。

Description

负极材料及其制备方法和应用以及含有其的锂离子电池 技术领域
整体而言，本公开涉及锂离子电池领域。更具体地说，本公开涉及包含含磷包覆层的硅基负极材料及其制备方法和其在锂离子电池中的应用，还涉及包含该硅基负极材料的锂离子电池。
背景技术
近年来，市场对于高能量密度锂离子电池的需求日益增长。目前商业化的锂离子电池负极材料主要为含碳材料。碳的理论比容量仅为372mAh/g，根本无法实现对高能量密度锂离子电池的需求。硅的理论比容量为4200mAh/g，理应成为最有前景的锂离子电池负极材料。然而，硅的充放电机理和石墨的充放电机理不同。充放电过程中Si与电解液中Li离子在界面处会不断生成固体电解质(SEI)薄膜。形成不可逆的SEI大量消耗了电解液和正极材料脱出的Li离子。因此，通常硅基负极材料的首次库伦效率(可简称为“首效”)仅在65-85％之间。另外，硅的电导率和锂离子扩散速度均低于石墨，这将限制硅在大电流大功率条件下的性能表现。
为解决上述问题，已经提出通过掺杂、纳米化、表面改性、预锂化等工艺来提高硅基负极材料的性能。在已公开工艺中，纳米化、包覆、合金化是硅基负极改性研发的重点。纳米化可以降低硅基材料在充放电过程中的体积形变，显著提升材料的循环稳定性。然而，纳米化的硅比表面积大，极易团聚，无法均匀的分布在多孔基体中，导致材料的循环稳定性和一致性较差。包覆是指在硅材料表面包裹一定厚度的保护层，既可以缓解硅的体积膨胀，又能够抑制硅材料与电解液之间的副反应，提升材料的首次库伦效率和循环稳定性。目前，常用的包覆手段是固相球磨、喷雾包覆、液相包覆等。但所述工艺获得的包覆层厚度、均匀性很难准确控制，在提升材料循环稳定性的同时，会不同程度的降低材料的可逆充电容量和倍率循环稳定性能。合金化是近年来新兴的一种改性工艺，通常情况下是将硅与铝、镁、铜等金属前驱体反应，制备Si-Al、Si-Mg、Si-Cu合金，既能够缓冲体积膨胀，又能提升硅材料的导电率，改善负极材料的某些电性能。但硅合金也 存在可逆充电容量低、部分合金水氧敏感等缺点，短期内尚无法满足商业化需求。由此可见，目前的制备工艺很难完全解决硅基负极循环稳定性差、首次库伦效率低、倍率循环稳定性能欠佳的缺陷。
CN108172775A报道了一种磷掺杂的硅基负极材料。其实施例中磷掺杂的硅基负极的比容量为610.1mAh/g时，首效为91.7％。CN108172775A制备过程需要喷雾干燥，产量低成本高。CN101179126B报道了一种用于锂离子电池的掺杂型硅基负极材料，其通过掺杂硼、铝、镓、锑和磷中至少一种元素，硅基负极材料的首效得到提升。CN101179126B在制备过程中需要进行高真空氩弧熔融焊接，反应温度高(＞1000℃)，反应工艺复杂(涉及熔融焊接、低温吹炼、快速冷却，行星球磨等操作)，成本较高。CN103400971A报道了硅酸锂掺杂的硅碳负极材料。其中，Si添加量为50％，Li2SiO3添加量为35％时，材料的比容量为1156.2mAh/g，首效为88.2％。
如上所述，虽然硅基负极材料的改造已经获得了一些进步，但是通常仅能提升硅基负极材料的一个性能，而不是提升其综合电性能。而在可操作地用于高能量密度锂离子电池时，却希望负极材料同时具有优良的可逆充电比容量、首效和循环充电容量保留率，特别是同时具有优良的首效和循环充电容量保留率。鉴于以上情况，仍然需要开发同时具有改善的首效、可逆充电比容量、循环充电容量保留率和导电性的硅基负极材料。另外，还需要一种操作简单的制备硅基负极材料的方法。
发明内容
为解决一个或多个现有技术中的上述问题，本公开提供一种包含含磷包覆层的硅基负极材料、该负极材料的制备方法和该负极材料在锂离子电池中的应用以及包含该负极材料的锂离子电池。本公开提供的负极材料具有提高的可逆充电容量(也称为“可逆充电比容量”)和首次库伦效率，特别适用于锂离子电池。
在一个实施方案中，本公开涉及一种负极材料，所述负极材料包含含硅材料和在所述含硅材料外周的含磷包覆层，其中所述含磷包覆层包含具有稠环芳烃结构片段的聚合物。
在一个实施方案中，本公开涉及一种制备负极材料的方法，其中 所述负极材料包含含硅材料和在所述含硅材料外周的含磷包覆层，所述含磷包覆层包含具有稠环芳烃结构片段的聚合物，并且所述方法包括：
(1)在30-80℃使含硅材料、磷源和溶剂接触，从而使磷源分布在含硅材料外周；和
(2)进行程序升温焙烧，使在含硅材料外周的磷源转化为包含具有稠环芳烃结构片段的聚合物，其中所述程序升温焙烧包括：
以第一升温速率升温到400-500℃的第一温度，
以第二升温速率升温到600-800℃的第二温度，其中第二升温速率低于第一升温速率，和
在所述第二温度下保温。
在一个实施方案中，本公开涉及由上述方法制备的负极材料。
在一个实施方案中，本公开涉及上述负极材料在锂离子电池中的应用。
在一个实施方案中，本公开涉及一种锂离子电池，所述锂离子电池包含具有上述负极材料的负极、正极、隔膜和电解液。
具体地说，本发明可以体现为以下项：
1、一种电池负极材料，所述负极材料包括聚合物锂盐、磷源和活性组分，所述活性组分含有硅元素。
2、第1项的负极材料，其中，所述聚合物锂盐的重均分子量为2000-5000000，优选为80000-240000；
优选地，所述聚合物锂盐的分子链上具有-C(O)-OLi基团；
优选地，所述聚合物锂盐选自聚丙烯酸锂、聚甲基丙烯酸锂、聚马来酸锂、聚富马酸锂、羧甲基纤维素锂和海藻酸锂中的至少一种。
3、第1或2项的负极材料，其中，以所述负极材料的总量为基准，聚合物锂盐的含量为1-15重量％，磷源的含量为10-60重量％，活性组分的含量为25-75重量％；
优选地，以所述负极材料的总量为基准，聚合物锂盐的含量为3-15重量％，磷源的含量为14-45重量％，活性组分的含量为40-75重量％。
4、第1-3项中任意一项的负极材料，其中，所述磷源通过化学键与硅元素连接，优选所述化学键为P(O)-O-Si；
优选地，所述磷源为多元磷酸，进一步优选为植酸；
优选地，所述磷源包覆在所述硅元素的表面。
5、第1-4项中任意一项的负极材料，其中，所述负极材料中还含有导电剂；
优选地，所述导电剂选自碳纳米管、乙炔黑和导电炭黑中的至少一种；
优选地，以所述负极材料的总量为基准，所述导电剂的含量为1-10重量％。
6、一种电池负极材料的制备方法，该制备方法包括：
(1)将硅源、磷源和溶剂混合；
(2)将步骤(1)混合得到的物料进行干燥；
(3)将所述干燥得到的固体物质与聚合物锂盐混合。
7、第6项的制备方法，其中，所述硅源包括硅粉；
优选地，所述磷源为多元磷酸，优选为植酸；
优选地，所述溶剂为有机溶剂，优选选自甲苯、N,N-二甲基甲酰胺、N,N-二甲基乙酰胺和N-甲基吡咯烷酮中的至少一种。
8、第6项的制备方法，其中，步骤(1)所述混合包括：
将所述磷源和溶剂混合，然后加入硅源；
优选地，所述磷源和硅源的质量比为0.1-2：1，进一步优选为0.5-1：1；
优选地，步骤(1)混合得到的物料的固含量为5-40重量％。
9、第6-8项中任意一项的制备方法，其中，步骤(3)中，所述干燥得到的固体物质与聚合物锂盐的质量比为1：(0.03-0.15)，优选为1：(0.08-0.13)；
优选地，所述聚合物锂盐的重均分子量为2000-5000000，优选为80000-240000；
优选地，所述聚合物锂盐的分子链上具有-C(O)-OLi基团；
优选地，所述聚合物锂盐选自聚丙烯酸锂、聚甲基丙烯酸锂、聚马来酸锂、聚富马酸锂、羧甲基纤维素锂和海藻酸锂中的至少一种；
优选地，步骤(3)所述混合在水的存在下进行；
优选地，该方法还包括在步骤(3)中引入导电剂；
优选地，所述导电剂选自碳纳米管、乙炔黑和导电炭黑中的至少一种；
优选地，所述干燥得到的固体物质与导电剂的质量比为1：(0.01-0.12)，优选为1：(0.06-0.1)。
10、第6-9项中任意一项的制备方法制得的电池负极材料。
11、第1-5和10项中任意一项的电池负极材料在锂离子电池中的应用。
12、一种锂离子电池，所述锂离子电池包括第1-5和10项中任意一项的电池负极材料、正极材料、隔膜和电解液；
优选地，所述锂离子电池为液态锂离子电池、半固态锂离子电池或者全固态锂离子电池。
本公开提供的负极材料具有以下优势：
(1)本公开的负极材料具有含磷包覆层。在程序升温过程的高温下，一些磷元素可扩散进入硅中形成占位掺杂，由此改善硅基负极材料的导电性；
(2)本公开的含磷包覆层包含具有稠环芳烃结构片段的聚合物，意味着该含磷包覆层具有致密的结构。一方面，致密结构的包覆层可以抵抗硅基负极材料在充放电过程常发生的体积膨胀，保证了电池的结构完整性和安全性。另一方面，致密结构的包覆层更有效地隔绝了锂离子接近硅基负极材料的通道，降低和避免了不可逆SEI的形成，相应缓解和消除了由此对电性能(例如，首效、可逆充电容量和循环充电容量保留率)的不利影响；
(3)本公开的含磷包覆层通过高温处理获得。高温处理将脱除包覆层表面上的至少部分极性基团。因此，一方面，本公开的负极材料虽然具有很小的粒径，中值粒径甚至可以在纳米范围，但是不易于发生团聚，从而具有优异的储存稳定性和分散性。另外，本公开的负极材料更方便进行进一步的表面改性，从而具有优异的可加工性。
附图说明
附图用以辅助对本发明的进一步理解，并且构成说明书的一部分，与下面的具体实施方式一起用于说明本发明，但并不构成对本发明的限制。在附图中：
图1显示在对比例1和实施例1-3中涉及的含磷包覆层的中间体的透射电子显微镜(TEM)图；
图2显示实施例1获得的负极材料P1的元素线扫描分布图；
图3显示实施例1获得的负极材料P1和对比例2获得的负极材料cP2的 13C-NMR图；
图4显示实施例1获得的负极材料P1的 29Si-NMR谱图；
图5显示利用实施例1的负极材料P1的锂离子电池的首次充放电曲线；
图6显示利用实施例1的负极材料P1的锂离子电池的倍率循环稳定性测试曲线；
图7显示利用实施例1的负极材料P1的锂离子电池的循环稳定性测试曲线；
图8显示利用对比例2的负极材料cP2的锂离子电池的倍率循环稳定性测试曲线；和
图9显示利用对比例2的负极材料cP2的锂离子电池的循环稳定性测试曲线。
具体实施方式
在本文中所披露的范围的端点和任何值都不限于该精确的范围或值，这些范围或值应当理解为包含接近这些范围或值的值。对于数值范围来说，各个范围的端点值之间、各个范围的端点值和单独的点值之间，以及单独的点值之间可以彼此组合而得到一个或多个新的数值范围，这些数值范围应被视为在本文中具体公开。
除了在实施例外，在本文中，参数的所有数值都应理解为在所有情况下均由术语“约”修饰，无论“约”是否实际上出现在该数值之前。
在本说明书中，所述中值粒径(或D 50)，是指累计粒度分布百分数达到50％时所对应的粒径。中值粒径常用来表示粉体的平均粒度。
在一个实施方案中，本公开涉及一种负极材料，所述负极材料包含含硅材料和在所述含硅材料外周的含磷包覆层，其中所述含磷包覆层包含具有稠环芳烃结构片段的聚合物。
在本公开的负极材料中，含磷包覆层厚度很薄，并且厚度的均一性高。通常，含磷包覆层厚度的厚度为2-6纳米。
含硅材料选自单质硅、SiOx和含硅合金中的至少一种，其中 0.6<x<1.5。优选，含硅材料为单质硅。通常以硅粉的形式使用单质硅。优选硅粉的中值粒径为0.05-10μm。
含硅材料可以通过商购得到，也可以通过已知方法制备得到。
优选地，含硅合金选自硅-铝合金、硅-镁合金、硅-锆合金和硅-硼合金中的至少一种。对含硅合金中硅的含量没有特别限定，其选择范围较宽。例如，以含硅合金的总量为基准，硅的含量可以为10-50重量％。对含硅合金的制备方法也没有特别的限定。举例来说，在此提供一种硅-铝合金的制备方法，所述方法包括以下步骤：1)将铝粉、硅粉在惰性气氛保护下，球磨30min；和2)将上述混合物在900℃下高温处理10h。
在一个变体中，具有稠环芳烃结构片段的聚合物由选自有机多元磷酸及其酯或盐，优选为植酸的磷源形成。
具有稠环芳烃结构片段的聚合物的稠环芳烃结构片段可以通过 13C-NMR来表征。在一个变体中，具有稠环芳烃结构片段的聚合物的 13C-NMR谱图在110ppm-140ppm的位置存在信号，从而显示了稠环芳烃结构片段的存在。 13C-NMR谱图中涉及稠环芳烃的化学位移公开在以下文献中：Harris,K.J.,Reeve Z.E.M.,et al.Electrochemical Changes in Lithium-Battery Electrodes Studied Using  7Li NMR and Enhanced  13C NMR of Graphene and Graphitic Carbons[J].Chem.Mater.2015,27,9,3299–3305，在此将其全文引入作为参考。
在一个变体中，含硅材料外周的含磷包覆层中的磷和含硅材料中的硅通过化学键连接，优选所述化学键为P(O)-O-Si。通过化学键连接，含硅材料和其外周的含磷包覆层更紧密连接起来。磷与硅通过P(O)-O-Si连接可以通过 29Si-NMR谱图来表征。
任选地，负极材料可以进一步包含碳层，其位于含磷包覆层外周。碳层可以形成负极材料的外壳，其中容纳含硅材料和在所述含硅材料外周的含磷包覆层。碳层可以是多孔结构。对多孔结构的孔径分布没有特别的限定。
任选地，负极材料可以进一步包含聚合物锂盐，优选聚合物锂盐的分子链上具有-C(O)-OLi基团。该基团可以通过全反射傅里叶变换吸收红外光谱表征获得。
在负极材料中引入聚合物锂盐，可补偿负极材料在充放电过程中 损失的锂，由此可提高负极材料的可逆充电容量和首效。
聚合物锂盐优选选自聚丙烯酸锂、聚甲基丙烯酸锂、聚马来酸锂、聚富马酸锂、羧甲基纤维素锂和海藻酸锂中的至少一种。
对聚合物锂盐的分子量没有特别的限定，选择范围较宽。优选地，所述聚合物锂盐的重均分子量为2000-5000000，优选为80000-240000。
聚合物锂盐可以通过商购得到，也可以通过已知方法制备得到。例如，所述聚丙烯酸锂可以通过聚丙烯酸和锂源(优选为氢氧化锂)在溶剂(例如，水)存在下反应得到。所述聚甲基丙烯酸锂可以通过聚甲基丙烯酸和锂源(优选为氢氧化锂)在溶剂(例如，水)存在下反应得到。所述聚马来酸锂可以通过聚马来酸和锂源(优选为氢氧化锂)在溶剂(例如，水)存在下反应得到。所述聚富马酸锂可以通过聚富马酸和锂源(优选为氢氧化锂)在溶剂(例如，水)存在下反应得到。所述羧甲基纤维素锂可以通过羧甲基纤维素和/或其盐(例如钠盐)和锂源(优选为氢氧化锂和/或氧化锂)在溶剂(例如，水)存在下反应得到。所述海藻酸锂可以通过海藻酸和/或其盐(例如钠盐)和锂源(优选为氢氧化锂和/或氧化锂)在溶剂(例如，水)存在下反应得到。对具体的反应过程，可以按照本领域常规反应进行，在此不再赘述。
聚合物锂盐可以包含在含磷包覆层中，也可以包含在碳层中。优选的是，聚合物锂盐包含在碳层中，更优选聚合物锂盐的至少一部分锂离子插层在多孔碳层中。
对于负极材料中聚合物锂盐的含量没有特别的限定，选择范围较宽。优选地，以所述负极材料的总量为基准，所述聚合物锂盐的含量为0-34重量％，更优选为10-30重量％。
任选地，负极材料进一步包含石墨。尽管碳的理论容量远低于硅，但是在负极材料引入石墨可以补偿硅的较低导电率，同时还可以大幅度改善循环充电容量保留率。使用石墨也不存在硅负极材料在充放电时所经历的体积膨胀问题。
任选地，负极材料进一步包含导电剂。导电剂优选选自碳纳米管、乙炔黑和导电炭黑中的至少一种。所述碳纳米管、乙炔黑和导电炭黑具有本领域技术人员常规理解的含义，并可以商购得到。
优选地，以所述负极材料的总量为基准，所述导电剂的含量为1-10 重量％，更优选为1-6重量％。
本公开的负极材料呈现颗粒形式。当未在负极材料中引入石墨时，负极材料具有小的中值粒径(D50)，一般为0.1-20微米，并且粒径分布更窄。优选负极材料呈现纳米颗粒形式。负极材料纳米化进一步改善了综合电性能。当在负极材料中引入石墨时，负极材料的尺寸增加。例如，含有石墨时，负极材料的中值粒径可以为1-25微米。
在一个实施方案中，本公开涉及一种制备负极材料的方法，其中所述负极材料包含含硅材料和在所述含硅材料外周的含磷包覆层，所述含磷包覆层包含稠环芳烃结构片段，并且所述方法包括：
(1)在30-80℃使含硅材料、磷源和溶剂接触，从而使磷源分布在含硅材料外周；和
(2)进行程序升温焙烧，使在含硅材料外周的磷源转化为包含具有稠环芳烃结构片段的聚合物，其中所述程序升温焙烧包括：
以第一升温速率升温到400-500℃的第一温度，
以第二升温速率升温到600-800℃的第二温度，其中第二升温速率低于第一升温速率，和
在所述第二温度下保温。
磷源为可以转化为包含稠环芳烃结构片段的聚合物的任何含磷的前体，例如通过缩聚进行转化。优选磷源选自有机多元磷酸及其酯或盐，优选为植酸。
在步骤(1)中，磷源和含硅材料的质量比为0.1-2：1，优选为0.5-1：1。可以选择该范围中任意值，例如为0.1：1、0.5：1、1：1、1.5：1、2：1。
步骤(1)中使用的溶剂可以为本领域常规使用的有机溶剂，优选为甲苯、N,N-二甲基甲酰胺、N,N-二甲基乙酰胺和N-甲基吡咯烷酮中的至少一种。溶剂的加入量使得，在步骤(1)中的物料的固含量为5-40重量％，优选为5-30重量％。
步骤(1)可以通过如下操作进行：先将磷源和溶剂混合，然后加入含硅材料，升温到30-80℃并保留0.5-4小时；或者先将含硅材料和溶剂混合，然后加入磷源，升温到30-80℃并保留0.5-4小时。优选先将磷源和溶剂混合，然后加入含硅材料，升温到30-80℃并保留1-4小时。
通过步骤(1)，磷源均匀分布在含硅材料外周，形成含磷包覆层 的中间体。发明人意外地发现，通过在升温(例如30-80℃)，而不是在室温下进行步骤(1)，得到的含磷包覆层的中间体的厚度降低，并且厚度的均一性更高。通常，含磷包覆层的中间体的厚度为3-15纳米，优选为4-10纳米。
在步骤(2)的程序升温焙烧中，以1-10℃/min，优选5-10℃/min的第一升温速率升温至450-500℃的第一温度，例如480℃；再以1-5℃/min，优选1-3℃/min的第二升温速率升温至600-650℃的第二温度，例如620℃；在所述第二温度下保温1-8h，优选2-4h。
通过在高温下进行程序升温焙烧，有助于磷源转化为包含具有稠环芳烃结构片段的聚合物。同时，高温操作也促进了磷掺杂到硅中，并脱除包覆层表面上的至少部分极性基团(例如通过脱除磷酸酯基团)。不希望束缚于任何理论，发明人认为，磷掺杂硅改善了硅基负极材料的导电性。具有稠环芳烃结构片段的聚合物赋予含磷包覆层致密的结构。由此可以抵抗硅基负极材料在充放电过程常发生的体积膨胀，保证了电池的结构完整性和安全性。同时，致密结构的包覆层更有效地隔绝了锂离子接近硅基负极材料的通道，降低和避免了不可逆SEI的形成，相应缓解和消除了由此对电性能的不利影响。另外，高温操作也脱除了包覆层表面上的至少部分极性基团，使得到的负极材料具有优异的储存稳定性、分散性和可加工性。
在一个实施方案中，本公开涉及由上述方法制备的负极材料。
在一个实施方案中，本公开涉及上述负极材料在锂离子电池中的应用。与传统纯石墨负极材料相比，上述负极材料由于含有理论容量更高的硅，从而可逆充电比容量显著提升，因此在将上述负极材料用于锂离子电池中时，可以提高锂电池的能量密度。
在一个实施方案中，本公开涉及一种锂离子电池，所述锂离子电池包含具有上述负极材料的负极、正极、隔膜和电解液。
根据本公开的实施方案的锂离子电池具有本领域技术人员所公知的结构。一般来说，隔膜位于正极和负极之间。并且，正极含有正极材料。对所述正极材料的具体组成没有特别的限定，可以为本领域常规使用的锂基正极材料。
隔膜可以为锂离子电池中常用的各种隔膜，例如聚丙烯微孔膜、聚乙烯毡、玻璃纤维毡或超细玻璃纤维纸。
电解液可为各种常规的电解液，例如非水电解液。所述非水电解液为电解质锂盐在非水溶剂中形成的溶液。适用形成非水电解液的锂盐可以选自六氟磷酸锂(LiPF6)、高氯酸锂(LiClO4)、四氟硼酸锂(LiBF4)、六氟砷酸锂(LiAsF6)和六氟硅酸锂(LiSiF6)中的至少一种。适合的非水溶剂可以选自链状酸酯和环状酸酯及其混合物，其中链状酸酯可以为碳酸二甲酯(DMC)、碳酸二乙酯(DEC)、碳酸甲乙酯(EMC)、碳酸甲丙酯(MPC)和碳酸二丙酯(DPC)中的至少一种。环状酸酯可以为碳酸亚乙酯(EC)、碳酸亚丙酯(PC)和碳酸亚丁酯(BC)中的至少一种。
实施例
通过以下实施例使明本发明的特点和优点显而易见。实施例旨在描述而非以任何方式限制本发明。
测试方法
1.材料的确认
1.1透射电子显微镜图(TEM)
采用透射电子显微镜对样品的形貌进行表征。具体地，所述透射电子显微镜为日本电子株式会社的型号为JEM-2100的透射电子显微镜，测试条件：加速电压160KV。样品置于铜支持网后插入电镜进行观察，所述观察时使用80万倍的放大倍率。
1.2元素线扫描分布图
采用球差透射电镜对材料包覆层中的元素进行表征。具体地，所述透射电子显微镜为美国FEI公司的型号为Titan Cubed Themis G2 300型号的透射电子显微镜，测试条件：加速电压300KV，HAADF探测器收集信号，接收角为52-200mrad。样品置于超薄碳膜上进行观察，样品的成分分析由电镜配备的X射线能谱仪(Aztec X-max 100TLE)完成。
1.3碳核磁共振( 13C-NMR)图
采用日本电子株式会社JNMR-500型固体核磁共振波谱仪对材料微观结构进行表征。测试条件：8mm二氧化锆转子，转速5000-6000。 13C的共振频率为125.72MHz，化学位移参考值为四甲基硅烷。采用高功率去耦合和交叉极化的测试方案，扫描次数5000次。
1.4硅核磁共振( 29Si-NMR)图
采用日本电子株式会社JNMR-500型固体核磁共振波谱仪对材料微观结构进行表征。测试条件：8mm二氧化锆转子，转速5000-6000。 29Si的共振频率为79.49MHz，化学位移参考值为四甲基硅烷。采用高功率去耦合和交叉极化的测试方案，扫描次数5000次。
2.材料的电性能
将制备的负极材料组装成锂离子电池样品，采用武汉蓝电电池测试系统(CT2001B)对得到的锂离子电池样品的电化学性能进行测试。测试条件包括：电压范围0.05V-2V。每个负极材料组装10个纽扣电池形式的样品。在同样的电压和电流下测试样品的电池性能，取平均值作为测量值。
2.1首次充放电曲线
在0.05V-2V的电压范围，以及0.1C倍率下，对组装的锂离子电池样品进行首次充放电，获得其首次充放电曲线。电池测试系统(CT2001B)将给出测试电池的首次放电容量和首次充电容量。首次放电容量为负极材料的比容量，首次充电容量为负极材料的可逆充电比容量。通过两者可以计算出首次库伦效率(简称为“首效”)：
首次库伦效率＝负极材料的可逆充电比容量/负极材料的比容量。
2.2循环稳定性测试
在0.2C的倍率下，对组装的锂离子电池样品进行选定次数，例如20次、50次或100次充放电循环，测量每次循环时样品的可逆充电比容量，并由此计算各个循环的循环充电容量保留率，其中：
循环充电容量保留率＝相应循环序号下的可逆充电比容量/首次充电时的可逆充电比容量×100％
以循环次数为横坐标和循环充电容量保留率为纵坐标作图得到循环稳定性测试曲线。
2.3倍率循环稳定性测试
分别在1/3C、1/2C、1C、2C、3C和5C的充放电倍率下，对所述样品进行5次充放电循环，测量每次循环时样品的可逆充电比容量，并如上所述计算各个循环的循环充电容量保留率。
以循环次数为横坐标和循环充电容量保留率为纵坐标作图得到倍率循环稳定性测试曲线。
通常情况下，在相同倍率下，负极材料的循环充电容量保留率与 其导电率呈正相关性。也就是说，导电性越好的负极材料，在同一倍率下的循环充电容量保留率越高。因此，可以用倍率循环稳定性来反映负极材料的导电率。
3.试剂
聚丙烯酸锂通过自行制备得到。具体地说，取重均分子量240000的聚丙烯酸10g加入到40g去离子水中，配制质量分数为20％的聚丙烯酸溶液。称取3.4g氢氧化锂，加入到上述聚丙烯酸溶液中，于40℃下加热搅拌直至所有固体全部溶解，并在100℃干燥4h，得聚丙烯酸锂。
其他试剂通过商购获得。
实施例1
将8.425g N,N-二甲基甲酰胺和0.225g植酸混合形成混合溶液，向该混合溶液中加入0.45g硅粉(D50＝120nm)，在搅拌下升温到40℃并保留50分钟。取样进行透射电子显微镜测试，获得材料的TEM图，结果如图1中的(b)所示。透射电子显微镜测试的数据显示，在硅外周形成了4nm厚度的含磷包覆层的中间体。另外，由于硅属于晶体材料，具有晶格条纹，而含磷包覆层为有机物中间体，属于无定型结构，两者在TEM图中呈现不同图像纹理。因此，通过分辨TEM中晶格条纹与无定型结构质地纹理，绘制了含磷包覆层的中间体的边界，如图1的(b)中的曲线所示。含磷包覆层的中间体的厚度基本上均匀，与透射电子显微镜测试给出的数据相一致。
以5℃/min的第一升温速率升温至480℃，再以2℃/min的第二升温速率升温至620℃，在620℃下保温3小时。
冷却到室温后，获得产物，称为负极材料P1。
对负极材料P1取样，如上所述进行元素线扫描测试，获得材料的元素线扫描分布图，结果如图2所示。如图2显示，在由核心向外扫描的过程中，硅的含量逐渐减少，磷的含量在15-18.7nm范围内出现高峰。由此可见，在硅外周形成含磷包覆层，其厚度为3.7nm。
另外，如上所述对样品进行碳核磁共振测试，获得其 13C-NMR图，结果显示为图3中的在上图形。如图3的在上图形显示，在110-140ppm区域存在信号并且在138ppm和119ppm处出现峰，说明在硅外周的含磷包覆层中存在稠环芳烃结构片段。
另外，如上所述对样品进行硅核磁共振测试，获得其 29Si-NMR图，结果如图4所示。如图4显示，负极材料P1中存在P(O)-O-Si键，说明磷与硅通过P(O)-O-Si键连接。
如下制备用于进行负极材料的电性能测试的锂离子电池样品：取1g所得的负极材料P1，形成浆料并均匀涂覆在铜箔集流体上，在120℃烘干10h，得到含负极材料P1的负极N1。将负极N1、作为正极的金属锂片、作为电解液的1mol/L LiPF 6溶液(其中，体积比为3：7的碳酸乙烯酯和碳酸二乙酯的混合物作为其溶剂)，作为隔膜的聚丙烯微孔膜，组装为CR2016纽扣电池。
如上所述测试该纽扣电池的性能以表征实施例1所得的负极材料P1的电学性能。
图5为基于实施例1的负极材料P1的纽扣电池的首次充放电曲线。从图5中可知，实施例1的负极材料P1的首次放电容量(比容量)为3858mAh/g，首次充电容量(可逆充电比容量)为3442mAh/g，相应的首次库伦效率为89.2％。
图6为基于实施例1的负极材料P1的纽扣电池的倍率循环稳定性测试曲线。由图6可知，实施例1的负极材料P1在1/3C、1/2C、1C、2C、3C和5C的倍率下，循环充电容量保留率分别为100％、92％、81％、63％、37％和6％。
图7为基于实施例1的负极材料P1的纽扣电池的循环稳定性测试曲线。如图所示，实施例1的负极材料P1在0.2C的充放电倍率下，经100次循环后，循环充电容量保留率86.7％。
实施例2
将8.425g N,N-二甲基甲酰胺和0.225g植酸混合形成混合溶液，向该混合溶液中加入0.45g硅粉(D50＝120nm)，在搅拌下升温到60℃并保留90分钟。取样进行透射电子显微镜测试，获得材料的TEM图，结果如图1中的(c)所示。透射电子显微镜测试的数据显示，在硅外周形成了10nm厚度的含磷包覆层的中间体。另外，如上所述，通过分辨TEM中晶格条纹与无定型结构质地纹理，绘制了含磷包覆层的中间体的边界，如图1的(c)中的曲线所示。含磷包覆层的中间体的厚度基本上均匀，与透射电子显微镜测试给出的数据相一致。
以8℃/min的第一升温速率升温至500℃，再以3℃/min的第二升温速率升温至650℃，在650℃下保温2小时。
冷却到室温后，获得产物，称为负极材料P2。
对负极材料P2取样，如上所述进行元素线扫描测试，获得的元素线扫描分布图，其类似于图2。样品的 13C-NMR图类似于图3中的在上图形。样品的 29Si-NMR图类似于图4。因此负极材料P2具有类似于负极材料P1的形貌。
用负极材料P2替代负极材料P1，重复实施例1所述的制备用于进行负极材料的电性能测试的锂离子电池样品。测试结果表明，实施例2的负极材料P2的可逆充电容量为3208mAh/g，首次库伦效率为87.8％。实施例2的负极材料P2在0.2C的充放电倍率下，经100次循环后，循环充电容量保留率为87.4％。
实施例3
将8.425g N,N-二甲基甲酰胺和0.225g植酸混合形成混合溶液，向该混合溶液中加入0.45g硅粉(D50＝120nm)，在搅拌下升温到70℃并保留90分钟。取样进行透射电子显微镜测试，获得材料的TEM图，结果如图1中的(d)所示。透射电子显微镜测试的数据显示，在硅外周形成了12nm厚度的含磷包覆层的中间体。另外，如上所述，通过分辨TEM中晶格条纹与无定型结构质地纹理，绘制了含磷包覆层的中间体的边界，如图1的(d)中的曲线所示。含磷包覆层的中间体的厚度基本上均匀，与透射电子显微镜测试给出的数据相一致。
以10℃/min的第一升温速率升温至450℃，再以3℃/min的第二升温速率升温至600℃，在600℃下保温4小时。
冷却到室温后，获得产物，称为负极材料P3。
对负极材料P3取样，如上所述进行元素线扫描测试，获得的元素线扫描分布图，其类似于图2。样品的 13C-NMR图类似于图3的在上图形。样品的 29Si-NMR图类似于图4。因此负极材料P3具有类似于负极材料P1的形貌。
用负极材料P3替代负极材料P1，重复实施例1所述的制备用于进行负极材料的电性能测试的锂离子电池样品。测试结果表明，实施例3的负极材料P3的可逆充电容量为3119mAh/g，首次库伦效率为87.5％。实 施例3的负极材料P3在0.2C的充放电倍率下，经100次循环后，循环充电容量保留率为87.9％。
对比例1
将8.425g N,N-二甲基甲酰胺和0.225g植酸混合形成混合溶液，向该混合溶液中加入0.45g硅粉(D50＝120nm)，在搅拌下在室温下保留50分钟。取样进行透射电子显微镜测试，获得材料的TEM图，结果如图1中的(a)所示。透射电子显微镜测试的数据显示，在硅外周形成了具有不均匀厚度的较厚的含磷包覆层的中间体，其厚度在一些部分为20nm而在另一些部分为90nm。另外，如上所述，通过分辨TEM中晶格条纹与无定型结构质地纹理，绘制了含磷包覆层的中间体的边界，如图1的(a)中的曲线所示。含磷包覆层的中间体的厚度不均匀，与透射电子显微镜测试给出的数据相一致。
以5℃/min的第一升温速率升温至480℃，再以2℃/min的第二升温速率升温至620℃，在620℃下保温3小时。
冷却到室温后，获得产物，称为负极材料cP1。
对负极材料cP1进行取样。如上所述获得样品的 13C-NMR图，其类似于图3中的在上图形，意味着负极材料cP1的含磷包覆层中也含有包含稠环芳烃结构片段的聚合物。
用负极材料cP1替代负极材料P1，重复实施例1所述的制备用于进行负极材料的电性能测试的锂离子电池样品。测试结果表明，对比例1的负极材料cP1的可逆充电容量为2820mAh/g，首次库伦效率为84.3％。对比例1的负极材料cP1在0.2C的充放电倍率下，经100次循环后，循环充电容量保留率为65.9％。
对比例2
将8.425g N,N-二甲基甲酰胺和0.225g植酸混合形成混合溶液，向该混合溶液中加入0.45g硅粉(D50＝120nm)，在搅拌下升温到40℃并保留6小时。
冷却到室温后，获得产物，称为负极材料cP2。
对负极材料cP2进行取样和测试。如上所述获得样品的 13C-NMR图，结果显示为图3中的在下图形。如图3的在下图形显示，在110ppm-140 ppm内不存在信号，而在70ppm-80ppm处出现两组包峰，判断为植酸的13C-NMR信号峰，说明植酸并未发生缩聚，并不存在稠环芳烃结构片段。植酸的 13C-NMR图可参考文献：JR Zhou,JW Erdman Jr.Phytic acid in health and disease[J].Critical Reviews in Food Science and Nutrition,1995,35(6):495-508，在此将其全文引入作为参考。用负极材料cP2替代负极材料P1，重复实施例1所述的制备用于进行负极材料的电性能测试的锂离子电池样品。测试结果表明，对比例2的负极材料cP2的可逆充电容量为2621mAh/g，首次库伦效率为80.6％。
图8为基于对比例2的负极材料cP2的纽扣电池的倍率循环稳定性测试曲线。对比例2的负极材料cP2在1/3C、1/2C、1C、2C、3C和5C的倍率下，保留率分别为70％、60％、20％、5％、3％和1％。
将附图6与附图8相对比可见，在相同倍率下进行循环时，实施例1的负极材料P1比对比例2的负极材料获得了更好的充电容量保留率，由此显示实施例1的负极材料P1比对比例2的负极材料具有更好的导电率。
图9为基于对比例2的负极材料cP2的纽扣电池的循环稳定性测试曲线。如图9所示，对比例2的负极材料cP2在0.2C的充放电倍率下，经100次循环后，循环充电容量保留率小于18.9％。
实施例4
将实施例1的负极材料P1与石墨按照10：1的质量比共混，得到负极材料P4。对负极材料P4进行取样，并如上所述进行透射电子显微镜测试。测试结果表明石墨分布在外表面上。
用负极材料P4替代负极材料P1，重复实施例1所述的制备用于进行负极材料的电性能测试的锂离子电池样品。测试结果表明，实施例4的负极材料P4的可逆充电容量为552mAh/g，首次库伦效率为88.5％。实施例4的负极材料P4在0.2C的充放电倍率下，经100次循环后，循环充电容量保留率为89.2％。
实施例5
将实施例1的负极材料P1与聚丙烯酸锂按照10：1的质量比共混，得到负极材料P4。
用负极材料P5替代负极材料P1，重复实施例1所述的制备用于进行 负极材料的电性能测试的锂离子电池样品。测试结果表明，实施例5的负极材料P5的可逆充电容量为3289mAh/g，首次库伦效率为90.5％。实施例5的负极材料P5在0.2C的充放电倍率下，经100次循环后，循环充电容量保留率为85.5％。
实施例6
取1g实施例1的负极材料P1，将其与0.12g石油沥青加入到10g的N,N-二甲基甲酰胺中，超声搅拌40分钟。将搅拌结束后获得的浆料转移至50mL离心管内，以5000rpm的转速离心5分钟。收集下层固体，并在100℃干燥4h。得到沥青包覆的负极材料P1。将其置于管式炉中，以5℃/min的速率升温至800℃，并在氮气气氛下保温30分钟。自然冷却至室温。得到具有碳层外壳的负极材料P1。取聚丙烯酸锂0.125g，将其与具有碳层外壳的负极材料P1共同置于3mL去离子水中，并在室温下搅拌12h。随后，将获得的浆料置于冷阱温度-80℃、腔体真空度100pa的冷冻真空干燥箱中，干燥12h。使锂离子插层到具有碳层外壳的负极材料P1的碳层外壳中，得负极材料P6。
用负极材料P6替代负极材料P1，重复实施例1所述的制备用于进行负极材料的电性能测试的锂离子电池样品。测试结果表明，实施例6的负极材料P6的可逆充电容量为3552mAh/g，首次库伦效率为91.3％。实施例6的负极材料P6在0.2C的充放电倍率下，经100次循环后，循环充电容量保留率为90.4％。
实施例7
1)将0.45g硅粉(D50＝120nm)加入到8.65g N,N-二甲基甲酰胺/植酸混合溶液中(8.425g N,N-二甲基甲酰胺和0.225g植酸)，搅拌40min。
2)搅拌结束后，将上述浆料转移至50mL离心管内，以5000rpm转速，离心5min，收集下层固体，100℃干燥4h，得到含磷硅粉。
根据所述含磷硅粉的TEM照片，纳米硅粉表面包覆了一层含磷物质，形成了“核-壳”型结构。
根据含磷硅粉的X射线光电子能谱图，在所述材料中P元素与Si元素通过P(O)-O-Si结合，上述化学键可以保证包覆壳层可以稳定的存在，不受外界环境影响，为材料发挥优异的电性能奠定基础。
3)将重均分子量240000的聚丙烯酸10g加入到40g去离子水中，配制质量分数为20％的聚丙烯酸溶液，向上述聚丙烯酸溶液中，加入3.4g氢氧化锂，于40℃下加热搅拌直至所有固体全部溶解，得到含聚丙烯酸锂的浆料。
4)取聚丙烯酸锂含量为0.55g的浆料，依次加入4g含磷硅粉、0.25g导电炭黑，搅拌2h，得到含锂负极材料S-1的浆料。含锂负极材料S-1的各组分的含量列于表1中。
根据聚丙烯酸和步骤3)所得聚丙烯酸锂的全反射傅里叶变换吸收红外光谱可以看出，与氢氧化锂反应之前，聚丙烯酸中C＝O振动峰出现在1700cm -1，锂化反应后该峰位置蓝移到1580cm -1，这表明反应后C(O)-OH转变为了C(O)-OLi。
5)取1g步骤4)所得的含锂负极材料S-1的浆料均匀涂覆在铜箔集流体上，在120℃烘干10h，得到含锂负极材料S-1极片。
分别以步骤5)所得极片、金属锂片为正极、负极，使用1mol/L LiPF 6溶液为电解液(碳酸乙烯酯和碳酸二乙酯以3：7体积比混合作为溶剂)，聚丙烯微孔膜为隔膜，组装为CR2016纽扣电池，表征实施例所述含锂负极材料S-1的电学性能。
获得基于所述含锂负极材料S-1的纽扣电池的首次充放电曲线(测试电压范围0.05-3V，电流为50mA)。测试结果表明，所述含锂负极材料S-1的可逆充电容量为3000mAh/g，首次库伦效率为86.9％。
实施例8
1)将0.45g硅粉(D50＝120nm)加入到8.65g N,N-二甲基甲酰胺/植酸混合溶液中(8.425g N,N-二甲基甲酰胺和0.45g植酸)，搅拌40min。
2)搅拌结束后，将上述浆料转移至50mL离心管内，以5000rpm转速，离心5min，收集下层固体，100℃干燥4h，得到含磷硅粉。
含磷硅粉的TEM图和X射线光电子能谱图分别和实施例7所述含磷硅粉的相似。
3)将重均分子量2000000的聚丙烯酸10g加入到90g去离子水中，配制质量分数为10％的聚丙烯酸溶液，向上述聚丙烯酸溶液中，加入3.4g氢氧化锂，于40℃下加热搅拌直至所有固体全部溶解，得到含聚丙烯酸锂的浆料。
4)取聚丙烯酸锂含量为0.52g的浆料，依次加入4g含磷硅粉、0.25g导电炭黑，搅拌2h，得到含锂负极材料S-2的浆料。含锂负极材料S-2的各组分的含量列于表1中。
5)取1g步骤4)所得的含锂负极材料S-2的浆料均匀涂覆在铜箔集流体上，120℃烘干10h，得到含锂负极材料S-2的极片。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为含锂负极材料S-2制得的极片。测试结果表明，所述含锂负极材料S-2的可逆充电容量为2720mAh/g，首次库伦效率为85.2％。
实施例9
1)将0.45g硅粉(D50＝120nm)加入到8.65g N,N-二甲基甲酰胺/植酸混合溶液中(8.425g N,N-二甲基甲酰胺和0.09g植酸)，搅拌40min。
2)搅拌结束后，将上述浆料转移至50mL离心管内，以5000rpm转速，离心5min，收集下层固体，100℃干燥4h，得到含磷硅粉。
含磷硅粉的TEM图和X射线光电子能谱图分别和实施例7所述含磷硅粉的相似。
3)将重均分子量100000的聚丙烯酸10g加入到40g去离子水中，配制质量分数为20％的聚丙烯酸溶液，向上述聚丙烯酸溶液中，加入3.4g氢氧化锂，于40℃下加热搅拌直至所有固体全部溶解，得到含聚丙烯酸锂的浆料。
4)取聚丙烯酸锂含量为0.46g的浆料，依次加入4g含磷硅粉、0.25g导电炭黑，搅拌2h，得到含锂负极材料S-3的浆料。含锂负极材料S-3的各组分的含量列于表1中。
5)取1.5g步骤4)所得的含锂负极材料S-3的浆料均匀涂覆在铜箔集流体上，120℃烘干10h，得到含锂负极材料S-3的极片。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为含锂负极材料S-3制得的极片。测试结果表明，所述含锂负极材料S-3的可逆充电容量为2978mAh/g，首次库伦效率为86.1％。
实施例10
1)将0.45g硅粉(D50＝120nm)加入到8.65g N,N-二甲基甲酰胺/植酸混合溶液中(8.425g N,N-二甲基甲酰胺和0.225g植酸)，搅拌40min。
2)搅拌结束后，将上述浆料转移至50mL离心管内，以5000rpm转速，离心5min，收集下层固体，100℃干燥4h，得到含磷硅粉。
含磷硅粉的TEM图和X射线光电子能谱图分别和实施例7所述含磷硅粉的相似。
3)将重均分子量200000的聚丙烯酸10g加入到40g去离子水中，配制质量分数为20％的聚丙烯酸溶液，向上述聚丙烯酸溶液中，加入1.2g氢氧化锂，于40℃下加热搅拌直至所有固体全部溶解，得到含聚丙烯酸锂的浆料。
4)取聚丙烯酸锂含量为0.42g的浆料，依次加入4g含磷硅粉、0.25g导电炭黑，搅拌2h，得到含锂负极材料S-4的浆料。含锂负极材料S-4的各组分的含量列于表1中。
5)取1.5g步骤4)所得的含锂负极材料S-4的浆料均匀涂覆在铜箔集流体上，120℃烘干10h，得到含锂负极材料S-4的极片。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为含锂负极材料S-4制得的极片。测试结果表明，所述含锂负极材料S-4的可逆充电容量为2650mAh/g，首次库伦效率为83.1％。
实施例11
1)将0.45g氧化亚硅粉(D50＝120nm)加入到8.65g N,N-二甲基甲酰胺/植酸混合溶液中(8.425g N,N-二甲基甲酰胺和0.9g植酸)，搅拌40min。
2)搅拌结束后，将上述浆料转移至50mL离心管内，以5000rpm转速，离心5min，收集下层固体，100℃干燥4h，得到含磷氧化亚硅粉。
含磷氧化亚硅粉的TEM图和X射线光电子能谱图分别和实施例7所述含磷硅粉的相似。
3)将重均分子量200000的聚丙烯酸10g加入到40g去离子水中，配制质量分数为20％的聚丙烯酸溶液，向上述聚丙烯酸溶液中，加入0.35g氢氧化锂，于40℃下加热搅拌直至所有固体全部溶解，得到含聚丙烯酸锂的浆料。
4)取聚丙烯酸锂含量为0.34g的浆料，依次加入4g含磷氧化亚硅粉、0.25g导电炭黑，搅拌2h，得到含锂负极材料S-5的浆料。含锂负极材料S-5的各组分的含量列于表1中。
5)取1.2g步骤4)所得的含锂负极材料S-5的浆料均匀涂覆在铜箔集流体上，120℃烘干10h，得到含锂负极材料S-5的极片。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为含锂负极材料S-5制得的极片。测试结果表明，所述含锂负极材料S-5的可逆充电容量为1650mAh/g，首次库伦效率为73.5％。
实施例12
1)将0.45g硅粉(D50＝120nm)加入到8.65g N,N-二甲基甲酰胺/植酸混合溶液中(8.425g N,N-二甲基甲酰胺和0.225g植酸)，搅拌40min。
2)搅拌结束后，将上述浆料转移至50mL离心管内，以5000rpm转速，离心5min，收集下层固体，100℃干燥4h，得到含磷硅粉。
含磷硅粉的TEM图和X射线光电子能谱图分别和实施例7所述含磷硅粉的相似。
3)将重均分子量200000的聚丙烯酸10g加入到40g去离子水中，配制质量分数为20％的聚丙烯酸溶液，向上述聚丙烯酸溶液中，加入2g氧化锂，于40℃下加热搅拌直至所有固体全部溶解，得到含聚丙烯酸锂的浆料。
4)取聚丙烯酸锂含量为0.27g的浆料，依次加入4g含磷硅粉、0.25g导电炭黑，搅拌2h，得到含锂负极材料S-6的浆料。含锂负极材料S-6的各组分的含量列于表1中。
5)取1.2g步骤4)所得的含锂负极材料S-6的浆料均匀涂覆在铜箔集流体上，120℃烘干10h，得到含锂负极材料S-6的极片。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为含锂负极材料S-6制得的极片。测试结果表明，所述含锂负极材料S-6的可逆充电容量为3120mAh/g，首次库伦效率为87.2％。
实施例13
1)将0.45g氧化亚硅粉(D50＝120nm)加入到8.65g N,N-二甲基甲酰胺/植酸混合溶液中(8.425g N,N-二甲基甲酰胺和0.225g植酸)，搅拌40min。
2)搅拌结束后，将上述浆料转移至50mL离心管内，以5000rpm转速，离心5min，收集下层固体，100℃干燥4h，得到含磷氧化亚硅粉。
含磷氧化亚硅粉的TEM图和X射线光电子能谱图分别和实施例7所述含磷硅粉的相似。
3)将重均分子量200000的聚丙烯酸10g加入到40g去离子水中，配制质量分数为20％的聚丙烯酸溶液，向上述聚丙烯酸溶液中，加入0.3g氧化锂，于40℃下加热搅拌直至所有固体全部溶解，得到含聚丙烯酸锂的浆料。
4)取聚丙烯酸锂含量为0.21g的浆料，依次加入4g含磷氧化亚硅粉、0.05g导电炭黑，搅拌2h，得到含锂负极材料S-7的浆料。含锂负极材料S-7的各组分的含量列于表1中。
5)取1.2g步骤4)所得的含锂负极材料S-7的浆料均匀涂覆在铜箔集流体上，120℃烘干10h，得到含锂负极材料S-7的极片。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为含锂负极材料S-7制得的极片。测试结果表明，所述含锂负极材料S-7的可逆充电容量为1810mAh/g，首次库伦效率为80.1％。
实施例14
1)将0.45g硅粉(D50＝120nm)加入到8.65g N,N-二甲基甲酰胺/植酸混合溶液中(8.425g N,N-二甲基甲酰胺和0.225g植酸)，搅拌40min。
2)搅拌结束后，将上述浆料转移至50mL离心管内，以5000rpm转速，离心5min，收集下层固体，100℃干燥4h，得到含磷硅粉。
含磷硅粉的TEM图和X射线光电子能谱图分别和实施例7所述含磷硅粉的相似。
3)将重均分子量200000的聚丙烯酸10g加入到40g去离子水中，配制质量分数为20％的聚丙烯酸溶液，向上述聚丙烯酸溶液中，加入4.5g碳酸锂，于40℃下加热搅拌直至所有固体全部溶解，得到含聚丙烯酸锂的浆料。
4)取聚丙烯酸锂含量为0.18g的浆料，依次加入4g含磷硅粉、0.25g导电炭黑，搅拌2h，得到含锂负极材料S-8的浆料。含锂负极材料S-8的各组分的含量列于表1中。
5)取1g步骤4)所得的含锂负极材料S-8的浆料均匀涂覆在铜箔集流体上，120℃烘干10h，得到含锂负极材料S-8的极片。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为含锂负极材料S-8制得的极片。测试结果表明，所述含锂负极材料S-8的可逆充电容量为2950mAh/g，首次库伦效率为86.1％。
实施例15
1)将0.45g硅粉(D50＝120nm)加入到8.65g N,N-二甲基甲酰胺/植酸混合溶液中(8.425g N,N-二甲基甲酰胺和0.225g植酸)，搅拌40min。
2)搅拌结束后，将上述浆料转移至50mL离心管内，以5000rpm转速，离心5min，收集下层固体，100℃干燥4h，得到含磷硅粉。
含磷硅粉的TEM图和X射线光电子能谱图分别和实施例7所述含磷硅粉的相似。
3)将重均分子量120000的海藻酸10g加入到40g去离子水中，配制质量分数为20％的海藻酸溶液，向上述海藻酸溶液中，加入3.2g氢氧化锂，于40℃下加热搅拌直至所有固体全部溶解，得到含海藻酸锂的浆料。
4)取海藻酸锂含量为0.15g的浆料，依次加入4g含磷硅粉、0.25g导电炭黑，搅拌2h，得到含锂负极材料S-9的浆料。含锂负极材料S-9的各组分的含量列于表1中。
5)取1g步骤4)所得的含锂负极材料S-9的浆料均匀涂覆在铜箔集流体上，120℃烘干10h，得到含锂负极材料S-9的极片。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为含锂负极材料S-9制得的极片。测试结果表明，所述含锂负极材料S-9的可逆充电容量为2760mAh/g，首次库伦效率为83.5％。
实施例16
1)将0.45g硅粉(D50＝120nm)加入到8.65g N,N-二甲基甲酰胺/植酸混合溶液中(8.425g N,N-二甲基甲酰胺和0.225g植酸)，搅拌40min。
2)搅拌结束后，将上述浆料转移至50mL离心管内，以5000rpm转速，离心5min，收集下层固体，100℃干燥4h，得到含磷硅粉。
含磷硅粉的TEM图和X射线光电子能谱图分别和实施例7所述含磷硅粉的相似。
3)将重均分子量10000的羧甲基纤维素10g加入到40g去离子水中，配制质量分数为20％的羧甲基纤维素溶液，向上述羧甲基纤维素酸溶液中，加入2.5g氢氧化锂，于40℃下加热搅拌直至所有固体全部溶解，得到含羧甲基纤维素锂的浆料。
4)取羧甲基纤维素锂含量为0.13g的浆料，依次加入4g含磷硅粉、0.25g导电炭黑，搅拌2h，得到含锂负极材料S-10的浆料。含锂负极材料S-10的各组分的含量列于表1中。
5)取1.5g步骤4)所得的含锂负极材料S-10的浆料均匀涂覆在铜箔集流体上，120℃烘干10h，得到含锂负极材料S-10的极片。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为含锂负极材料S-10制得的极片。测试结果表明，10所述含锂负极材料S-10的可逆充电容量为2632mAh/g，首次库伦效率为81.4％。
实施例17
1)将0.45g硅粉(D50＝120nm)加入到8.65g N,N-二甲基甲酰胺/植酸混合溶液中(8.425g N,N-二甲基甲酰胺和0.225g植酸)，搅拌40min。
2)搅拌结束后，将上述浆料转移至50mL离心管内，以5000rpm转速，离心5min，收集下层固体，100℃干燥4h，得到含磷硅粉。
含磷硅粉的TEM图和X射线光电子能谱图分别和实施例7所述含磷硅粉的相似。
3)将重均分子量240000的聚甲基丙烯酸10g加入到40g去离子水中，配制质量分数为20％的聚甲基丙烯酸溶液，向上述聚甲基丙烯酸溶液中，加入2.5g氢氧化锂，于40℃下加热搅拌直至所有固体全部溶解，得到含聚甲基丙烯酸锂的浆料。
4)取聚甲基丙烯酸锂含量为0.13g的浆料，依次加入4g含磷硅粉、 0.25g导电炭黑，搅拌2h，得到含锂负极材料S-11的浆料。含锂负极材料S-11的各组分的含量列于表1中。
5)取1.5g步骤4)所得的含锂负极材料S-11的浆料均匀涂覆在铜箔集流体上，120℃烘干10h，得到含锂负极材料S-11的极片。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为含锂负极材料S-11制得的极片。测试结果表明，所述含锂负极材料S-11的可逆充电容量为2753mAh/g，首次库伦效率为83.6％。
实施例18
1)将0.45g硅粉(D50＝120nm)加入到8.65g N,N-二甲基甲酰胺/植酸混合溶液中(8.425g N,N-二甲基甲酰胺和0.225g植酸)，搅拌40min。
2)搅拌结束后，将上述浆料转移至50mL离心管内，以5000rpm转速，离心5min，收集下层固体，100℃干燥4h，得到含磷硅粉。
含磷硅粉的TEM图和X射线光电子能谱图分别和实施例7所述含磷硅粉的相似。
3)将重均分子量80000的聚马来酸10g加入到40g去离子水中，配制质量分数为20％的聚马来酸溶液，向上述聚马来酸溶液中，加入2.5g氢氧化锂，于40℃下加热搅拌直至所有固体全部溶解，得到含聚马来酸锂的浆料。
4)取聚马来酸锂含量为0.13g的浆料，依次加入4g含磷硅粉、0.25g导电炭黑，搅拌2h，得到含锂负极材料S-12的浆料。含锂负极材料S-12的各组分的含量列于表1中。
5)取1.5g步骤4)所得的含锂负极材料S-12的浆料均匀涂覆在铜箔集流体上，120℃烘干10h，得到含锂负极材料S-12的极片。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为含锂负极材料S-12制得的极片。测试结果表明，所述含锂负极材料S-12的可逆充电容量为2695mAh/g，首次库伦效率为82.1％。
实施例19
1)将0.45g硅粉(D50＝120nm)加入到8.65g N,N-二甲基甲酰胺/ 植酸混合溶液中(8.425g N,N-二甲基甲酰胺和0.225g植酸)，搅拌40min。
2)搅拌结束后，将上述浆料转移至50mL离心管内，以5000rpm转速，离心5min，收集下层固体，100℃干燥4h，得到含磷硅粉。
含磷硅粉的TEM图和X射线光电子能谱图分别和实施例7所述含磷硅粉的相似。
3)将重均分子量120000的聚富马酸10g加入到40g去离子水中，配制质量分数为20％的聚富马酸溶液，向上述聚富马酸溶液中，加入2.5g氢氧化锂，于40℃下加热搅拌直至所有固体全部溶解，得到含聚富马酸锂的浆料。
4)取聚富马酸锂含量为0.13g的浆料，依次加入4g含磷硅粉、0.25g导电炭黑，搅拌2h，得到含锂负极材料S-13的浆料。含锂负极材料S-13的各组分的含量列于表1中。
5)取1.5g步骤4)所得的含锂负极材料S-13的浆料均匀涂覆在铜箔集流体上，120℃烘干10h，得到含锂负极材料S-13的极片。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为含锂负极材料S-13制得的极片。测试结果表明，所述含锂负极材料S-13的可逆充电容量为2710mAh/g，首次库伦效率为82.5％。
对比例a
按照实施例7的方法制得负极材料D-1，不同的是，对比例1步骤3)不添加3.4g氢氧化锂。负极材料D-1的各组分的含量如表1所示。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为负极材料D-1制得的极片。
获得基于所述负极材料D-1的纽扣电池的首次充放电曲线。所述负极材料D-1的可逆充电容量为908mAh/g，首次库伦效率为38.9％。
对比例b
按照实施例7的方法，不同的是，负极材料制备过程中不加入磷源。具体地：
将重均分子量240000的聚丙烯酸10g加入到40g去离子水中，配制质量分数为20％的聚丙烯酸溶液，向上述聚丙烯酸溶液中，加入3.4g氢 氧化锂，于40℃下加热搅拌直至所有固体全部溶解，得到含聚丙烯酸锂的浆料；
取聚丙烯酸锂含量为0.55g的浆料，依次加入4g硅粉(D50＝120nm)、0.25g导电炭黑，搅拌2h，得到含锂负极材料D-2的浆料。含锂负极材料D-2的各组分的含量列于表1中。
取1g所述含锂负极材料D-2的浆料均匀涂覆在铜箔集流体上，120℃烘干10h，得到含锂负极材料D-2的极片。
按照实施例7的方法组装电池并进行电学性能测试，不同的是，将含锂负极材料S-1的极片替换为含锂负极材料D-2制得的极片。测试结果表明，所述含锂负极材料D-2的可逆充电容量为1650mAh/g，首次库伦效率为83.5％。
表1
Figure PCTCN2020118704-appb-000001
通过上述实施例以及结果可以看出，相对于对比例的负极材料，根据本公开的实施方案的负极材料，在用于锂离子电池时，在可逆充电容量、首次库伦效率和循环充电容量保留率，特别是在更长循环周期的充电保留率方面均获得了提高。
以上详细描述了本公开的优选实施方式，但是，本公开并不限于此。在本公开的技术构思范围内，可以对本公开的技术方案进行多种简单变型，包括各个技术特征以任何其它的合适方式进行组合，这些简单变型和组合同样应当视为本文所公开的内容，均属于本公开的保护范围。

Claims (15)

  1. 一种负极材料，所述负极材料包含含硅材料和在所述含硅材料外周的含磷包覆层，其中所述含磷包覆层包含具有稠环芳烃结构片段的聚合物。
  2. 根据权利要求1所述的负极材料，其中含硅材料选自单质硅、SiOx和含硅合金中的至少一种，其中0.6<x<1.5；
    优选含硅材料为单质硅；
    优选单质硅为中值粒径为0.05-10μm的硅粉的形式。
  3. 根据权利要求1所述的负极材料，其中具有稠环芳烃结构片段的聚合物的 13C-NMR谱图在110ppm-140ppm的位置存在信号；和/或
    其中含磷包覆层中的磷和含硅材料中的硅通过P(O)-O-Si键连接。
  4. 根据权利要求1所述的负极材料，其中负极材料进一步包含碳层，其位于含磷包覆层外周；
    优选碳层形成外壳，其中容纳含硅材料和在所述含硅材料外周的含磷包覆层；
    优选碳层是多孔碳层。
  5. 根据权利要求1所述的负极材料，其中负极材料进一步包含聚合物锂盐；
    优选聚合物锂盐优选选自聚丙烯酸锂、聚甲基丙烯酸锂、聚马来酸锂、聚富马酸锂、羧甲基纤维素锂和海藻酸锂中的至少一种；
    优选所述聚合物锂盐的重均分子量为2000-5000000；
    优选聚合物锂盐插层在多孔碳层中；
    优选，以所述负极材料的总量为基准，所述聚合物锂盐的含量为0-34重量％。
  6. 根据权利要求1所述的负极材料，其中负极材料进一步包含石墨；
    其中负极材料进一步包含导电剂；
    优选导电剂选自碳纳米管、乙炔黑和导电炭黑中的至少一种；
    优选，以所述负极材料的总量为基准，所述导电剂的含量为1-10重量％。
  7. 根据权利要求1所述的负极材料，其中负极材料的中值粒径为0.1-20微米。
  8. 一种制备负极材料的方法，其中所述负极材料包含含硅材料和在所述含硅材料外周的含磷包覆层，所述含磷包覆层包含具有稠环芳烃结构片段的聚合物，并且所述方法包括：
    (1)在30-80℃使含硅材料、磷源和溶剂接触，从而使磷源分布在含硅材料外周；和
    (2)进行程序升温焙烧，使在含硅材料外周的磷源转化为包含具有稠环芳烃结构片段的聚合物，其中所述程序升温焙烧包括：
    以第一升温速率升温到400-500℃的第一温度，
    以第二升温速率升温到600-800℃的第二温度，其中第二升温速率低于第一升温速率，和
    在所述第二温度下保温。
  9. 根据权利要求8所述的方法，其中磷源为可转化为包含稠环芳烃结构片段的聚合物的含磷前体；
    优选磷源选自有机多元磷酸及其酯或盐；
    优选磷源为植酸。
  10. 根据权利要求8所述的方法，其中在步骤(1)中，磷源和含硅材料的质量比为0.5-1：1。
  11. 根据权利要求8所述的方法，其中溶剂为甲苯、N,N-二甲基甲酰胺、N,N-二甲基乙酰胺和N-甲基吡咯烷酮中的至少一种；
    优选溶剂的加入量使得，在步骤(1)中的物料的固含量为5-40重量％。
  12. 根据权利要求8所述的方法，其中程序升温焙烧包括以1-10℃/min的第一升温速率升温至450-500℃；再以1-5℃/min的第二升温速率升温至600-650℃；在该温度下保温1-8h。
    优选以5-10℃/min的第一升温速率升温至450-500℃；再以1-3℃/min的第二升温速率升温至600-650℃；在该温度下保温2-4h。
  13. 根据权利要求8-12任一项所述的方法制备的负极材料。
  14. 根据权利要求1-7任一项或权利要求13所述的负极材料在锂离子电池中的应用。
  15. 一种锂离子电池，所述锂离子电池包含具有根据权利要求1-7任一项或权利要求13所述的负极材料的负极、正极、隔膜和电解液。
PCT/CN2020/118704 2019-10-09 2020-09-29 负极材料及其制备方法和应用以及含有其的锂离子电池 WO2021068793A1 (zh)

Priority Applications (8)

Application Number Priority Date Filing Date Title
BR112022005774A BR112022005774A2 (pt) 2019-10-09 2020-09-29 Material de eletrodo negativo, método de preparação para o mesmo, e aplicação do mesmo, e bateria de íon de lítio compreendendo o mesmo
AU2020363051A AU2020363051A1 (en) 2019-10-09 2020-09-29 Negative electrode material, preparation method therefor, and application thereof, and lithium ion battery comprising same
CN202080070424.9A CN114467195B (zh) 2019-10-09 2020-09-29 负极材料及其制备方法和应用以及含有其的锂离子电池
KR1020227015601A KR20220078682A (ko) 2019-10-09 2020-09-29 음극 재료, 이의 제조 방법, 및 용도, 및 이를 포함하는 리튬 이온 전지
CA3157355A CA3157355A1 (en) 2019-10-09 2020-09-29 Negative electrode material, comprising phosphorus-containing coating layer preparation and method thereof and litium ion battery comprising the same ___________________________
EP20874623.0A EP4044278A4 (en) 2019-10-09 2020-09-29 NEGATIVE ELECTRODE MATERIAL, PREPARATION METHOD AND APPLICATION THEREOF, AND LITHIUM-ION BATTERY INCLUDING SAME
JP2022521414A JP2022552485A (ja) 2019-10-09 2020-09-29 負極材料、その製造方法、及びその適用、並びにそれを含んでいるリチウムイオン電池
US17/754,393 US20220393152A1 (en) 2019-10-09 2020-09-29 Negative Electrode Material, Preparation Method Therefor, and Application Thereof, and Lithium Ion Battery Comprising Same

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
CN201910953233.6 2019-10-09
CN201910953279.8 2019-10-09
CN201910953233.6A CN112635719B (zh) 2019-10-09 2019-10-09 电池负极材料及其制备方法和应用以及锂离子电池
CN201910953279.8A CN112652755B (zh) 2019-10-09 2019-10-09 硅碳负极材料及其制备方法和应用以及锂离子电池

Publications (1)

Publication Number Publication Date
WO2021068793A1 true WO2021068793A1 (zh) 2021-04-15

Family

ID=75437696

Family Applications (2)

Application Number Title Priority Date Filing Date
PCT/CN2020/118704 WO2021068793A1 (zh) 2019-10-09 2020-09-29 负极材料及其制备方法和应用以及含有其的锂离子电池
PCT/CN2020/118720 WO2021068796A1 (zh) 2019-10-09 2020-09-29 负极材料及其制备方法和应用以及锂离子电池

Family Applications After (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/118720 WO2021068796A1 (zh) 2019-10-09 2020-09-29 负极材料及其制备方法和应用以及锂离子电池

Country Status (9)

Country Link
US (2) US20230148348A1 (zh)
EP (2) EP4044285A4 (zh)
JP (2) JP2022552485A (zh)
KR (2) KR20220078683A (zh)
CN (2) CN114467195B (zh)
AU (2) AU2020363053A1 (zh)
BR (2) BR112022005774A2 (zh)
CA (2) CA3155666A1 (zh)
WO (2) WO2021068793A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114373909A (zh) * 2021-12-21 2022-04-19 广东邦普循环科技有限公司 一种负极材料及其制备方法和应用
WO2023039074A1 (en) * 2021-09-08 2023-03-16 Koppers Delaware, Inc. Dispersion of coal tar pitch for coating graphitic materials and use in li-ion battery electrode production

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113816384B (zh) * 2021-08-30 2023-07-18 上海纳米技术及应用国家工程研究中心有限公司 一种掺磷多孔碳包覆氧化亚硅材料的制备方法及其产品
CN114200266A (zh) * 2021-12-09 2022-03-18 西安交通大学 一种基于聚3-己基噻吩的电晕放电检测材料及其制备方法
CN114784251B (zh) * 2022-05-13 2024-06-18 中国科学技术大学 一种磷包覆的负极材料及其制备方法和应用
CN115806290B (zh) * 2022-12-06 2024-08-13 广东凯金新能源科技股份有限公司 人造石墨锂离子电池负极材料及其制备方法
CN117293312B (zh) * 2023-11-24 2024-03-12 深圳市贝特瑞新能源技术研究院有限公司 一种硬碳材料及其制备方法和应用、钠离子电池
CN117976819B (zh) * 2024-03-29 2024-09-06 宁德时代新能源科技股份有限公司 负极极片、负极极片的制备方法、电池和用电设备

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101179126A (zh) 2003-03-26 2008-05-14 佳能株式会社 电极材料、电极结构及具有该电极结构的二次电池
JP2010287505A (ja) * 2009-06-12 2010-12-24 Toyota Motor Corp 二次電池用負極の製造方法及び電極構造
CN103400971A (zh) 2013-07-29 2013-11-20 宁德新能源科技有限公司 硅基复合材料及其制备方法以及其应用
CN106463707A (zh) * 2014-02-21 2017-02-22 克雷多斯公司 官能化iv a族颗粒框架的纳米硅材料制备
CN106531992A (zh) * 2016-11-09 2017-03-22 南方科技大学 一种含硅复合材料及其制备方法与应用
CN108063221A (zh) * 2017-05-11 2018-05-22 华为技术有限公司 制备负极材料的方法、负极材料、负极极片和锂离子电池
CN108172775A (zh) 2017-11-23 2018-06-15 合肥国轩高科动力能源有限公司 一种锂离子电池用磷掺杂硅碳负极材料及其制备方法
WO2020091876A1 (en) * 2018-11-02 2020-05-07 Nanograf Corporation Advanced negative electrode architecture for high power applications
CN111916686A (zh) * 2019-05-08 2020-11-10 中国石油化工股份有限公司 含磷锂离子电池负极材料及其制备工艺

Family Cites Families (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1913200B (zh) * 2006-08-22 2010-05-26 深圳市贝特瑞电子材料有限公司 锂离子电池硅碳复合负极材料及其制备方法
JP5298558B2 (ja) * 2007-08-30 2013-09-25 ソニー株式会社 二次電池用負極およびその製造方法、二次電池およびその製造方法、ならびに電子機器
JP5245592B2 (ja) * 2008-07-14 2013-07-24 信越化学工業株式会社 非水電解質二次電池用負極材、ならびにリチウムイオン二次電池及び電気化学キャパシタ
KR101519979B1 (ko) * 2013-03-25 2015-05-20 한국세라믹기술원 리튬이온이차전지용 음극 조성물
JP6181590B2 (ja) * 2014-04-02 2017-08-16 信越化学工業株式会社 非水電解質二次電池用負極及び非水電解質二次電池
US9859554B2 (en) * 2014-07-03 2018-01-02 GM Global Technology Operations LLC Negative electrode material for lithium-based batteries
KR101726037B1 (ko) * 2015-03-26 2017-04-11 (주)오렌지파워 실리콘계 음극 활물질 및 이의 제조 방법
CN105047887B (zh) * 2015-06-19 2017-03-15 苏州大学 一种改善锂离子电池硅负极材料的方法
CN106898736A (zh) * 2015-12-18 2017-06-27 比亚迪股份有限公司 一种锂离子电池用电极活性材料、锂离子电池极片及其制备方法和锂离子电池
CN109952670B (zh) * 2016-04-07 2022-09-13 存点有限公司 锂离子电池及其阳极
CN105932284B (zh) * 2016-07-13 2019-01-22 盐城工学院 一种介孔碳紧密包覆型复合材料及其制备方法和应用
US11177471B2 (en) * 2016-12-16 2021-11-16 Johnson Matthey Public Company Limited Anode materials for lithium ion batteries and methods of making and using same
JP6908058B2 (ja) * 2017-02-09 2021-07-21 株式会社村田製作所 二次電池、電池パック、電動車両、電動工具および電子機器
CN108063216A (zh) * 2017-11-27 2018-05-22 浙江衡远新能源科技有限公司 一种锂电池负极极片及其制备方法
CN108461723B (zh) * 2018-02-11 2020-08-18 安普瑞斯（南京）有限公司 一种用于锂离子电池的硅基复合材料及其制备方法
CN110137485B (zh) * 2019-06-26 2021-02-09 珠海冠宇电池股份有限公司 一种含有表面修饰膜的硅负极材料的制备方法
CN112652755B (zh) * 2019-10-09 2022-07-12 中国石油化工股份有限公司 硅碳负极材料及其制备方法和应用以及锂离子电池
CN112635745B (zh) * 2019-10-09 2022-10-11 中国石油化工股份有限公司 复合材料及其制备方法和锂电池负极以及锂电池
CN111146422B (zh) * 2019-12-26 2023-07-07 宁德新能源科技有限公司 负极材料及包含其的电化学装置和电子装置
CN111146434A (zh) * 2019-12-26 2020-05-12 宁德新能源科技有限公司 负极材料及包含其的电化学装置和电子装置
CN111653738B (zh) 2020-04-20 2022-01-07 万向一二三股份公司 一种锂离子电池硅碳负极材料及其制备方法

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101179126A (zh) 2003-03-26 2008-05-14 佳能株式会社 电极材料、电极结构及具有该电极结构的二次电池
JP2010287505A (ja) * 2009-06-12 2010-12-24 Toyota Motor Corp 二次電池用負極の製造方法及び電極構造
CN103400971A (zh) 2013-07-29 2013-11-20 宁德新能源科技有限公司 硅基复合材料及其制备方法以及其应用
CN106463707A (zh) * 2014-02-21 2017-02-22 克雷多斯公司 官能化iv a族颗粒框架的纳米硅材料制备
CN106531992A (zh) * 2016-11-09 2017-03-22 南方科技大学 一种含硅复合材料及其制备方法与应用
CN108063221A (zh) * 2017-05-11 2018-05-22 华为技术有限公司 制备负极材料的方法、负极材料、负极极片和锂离子电池
CN108172775A (zh) 2017-11-23 2018-06-15 合肥国轩高科动力能源有限公司 一种锂离子电池用磷掺杂硅碳负极材料及其制备方法
WO2020091876A1 (en) * 2018-11-02 2020-05-07 Nanograf Corporation Advanced negative electrode architecture for high power applications
CN111916686A (zh) * 2019-05-08 2020-11-10 中国石油化工股份有限公司 含磷锂离子电池负极材料及其制备工艺

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
HARRIS, K. J.REEVE Z. E. M. ET AL.: "Electrochemical Changes in Lithium-Battery Electrodes Studied Using Li NMR and Enhanced C NMR of Graphene and Graphitic Carbons", J]. CHEM. MATER., vol. 27, no. 9, 2015, pages 3299 - 3305
JR ZHOUJW ERDMAN JR.: "Phytic acid in health and disease", J]. CRITICAL REVIEWS IN FOOD SCIENCE AND NUTRITION, vol. 35, no. 6, 1995, pages 495 - 508
See also references of EP4044278A4

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023039074A1 (en) * 2021-09-08 2023-03-16 Koppers Delaware, Inc. Dispersion of coal tar pitch for coating graphitic materials and use in li-ion battery electrode production
CN114373909A (zh) * 2021-12-21 2022-04-19 广东邦普循环科技有限公司 一种负极材料及其制备方法和应用

Also Published As

Publication number Publication date
WO2021068796A1 (zh) 2021-04-15
CN114467198B (zh) 2024-08-30
KR20220078682A (ko) 2022-06-10
CN114467198A (zh) 2022-05-10
CA3155666A1 (en) 2021-04-15
EP4044285A4 (en) 2024-01-10
EP4044285A1 (en) 2022-08-17
US20230148348A1 (en) 2023-05-11
BR112022005422A2 (pt) 2022-06-21
JP2022552486A (ja) 2022-12-16
AU2020363051A1 (en) 2022-04-14
CN114467195B (zh) 2024-08-30
AU2020363053A1 (en) 2022-04-14
US20220393152A1 (en) 2022-12-08
EP4044278A4 (en) 2024-01-03
KR20220078683A (ko) 2022-06-10
BR112022005774A2 (pt) 2022-06-21
EP4044278A1 (en) 2022-08-17
JP2022552485A (ja) 2022-12-16
CA3157355A1 (en) 2021-04-15
CN114467195A (zh) 2022-05-10

Similar Documents

Publication Publication Date Title
WO2021068793A1 (zh) 负极材料及其制备方法和应用以及含有其的锂离子电池
EP3561921B1 (en) Lithium ion secondary battery
KR101458309B1 (ko) 부피 변화를 완화할 수 있는 Si-블록 공중합체 코어-쉘 나노 입자 및 이를 이용한 리튬 이차전지용 음극활물질
TWI773667B (zh) 負極活性物質、混合負極活性物質材料、及負極活性物質的製造方法(一)
CN112652755B (zh) 硅碳负极材料及其制备方法和应用以及锂离子电池
WO2017145853A1 (ja) 負極活物質、混合負極活物質材料、非水電解質二次電池用負極、リチウムイオン二次電池、負極活物質の製造方法、及びリチウムイオン二次電池の製造方法
KR20180093014A (ko) 부극 활물질, 혼합 부극 활물질 재료, 비수 전해질 2차 전지용 부극, 리튬 이온 2차 전지, 부극 활물질의 제조 방법 및 리튬 이온 2차 전지의 제조 방법
CN112687852A (zh) 硅氧锂颗粒及其制备方法、负极材料、极片和电池
KR20180134898A (ko) 부극 활물질, 혼합 부극 활물질 재료, 부극 활물질의 제조 방법
JP2024517230A (ja) 均一に改質された一酸化ケイ素負極材料及びその調製方法と応用
CN114982009B (zh) 负极材料、负极极片及包含其的电化学装置及电子装置
CN112635719B (zh) 电池负极材料及其制备方法和应用以及锂离子电池
WO2023044866A1 (zh) 硅碳负极材料、负极极片、二次电池、电池模块、电池包和用电装置
Wang et al. Rapid fabrication of porous silicon/carbon microtube composites as anode materials for lithium-ion batteries
CN112299429A (zh) 一种硅氧化合物及使用它的二次电池
WO2024108558A1 (zh) 二次电池及用电装置
WO2024108573A1 (zh) 碳材料及其制备方法、以及含有其的二次电池和用电装置
WO2024026835A1 (zh) 复合负极活性材料及其制备方法、以及包含其的负极极片、二次电池及用电装置
Li et al. In-situ Preparation and Electrochemical Performance of an Urchin-like Carbon Nanofibers@ LiFePO4 Hybrid
WO2023074216A1 (ja) 粒子及びその製造方法と、二次電池及びその製造方法
CN116031405A (zh) 氮掺杂纳米碳材料及其制备方法、金属锂负极及其制备方法和金属锂电池
CN116805677A (zh) 一种硅碳复合材料及其制备方法、锂离子电池
CN116031374A (zh) 锑基合金负极材料及其制备方法以及负极极片和锂离子电池
JP2023512011A (ja) 負極活物質、その作製方法、二次電池、二次電池を含む電池モジュール、電池パック及び装置
CN117693830A (zh) 电化学装置和电子设备

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: 20874623

Country of ref document: EP

Kind code of ref document: A1

REG Reference to national code

Ref country code: BR

Ref legal event code: B01A

Ref document number: 112022005774

Country of ref document: BR

ENP Entry into the national phase

Ref document number: 3157355

Country of ref document: CA

ENP Entry into the national phase

Ref document number: 2022521414

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2020363051

Country of ref document: AU

Date of ref document: 20200929

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 20227015601

Country of ref document: KR

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 2020874623

Country of ref document: EP

Effective date: 20220509

ENP Entry into the national phase

Ref document number: 112022005774

Country of ref document: BR

Kind code of ref document: A2

Effective date: 20220325

WWE Wipo information: entry into national phase

Ref document number: 522432192

Country of ref document: SA

WWE Wipo information: entry into national phase

Ref document number: 522432192

Country of ref document: SA