WO2021093865A1 - 一种负极材料及其制备方法和锂离子电池 - Google Patents

一种负极材料及其制备方法和锂离子电池 Download PDF

Info

Publication number
WO2021093865A1
WO2021093865A1 PCT/CN2020/128783 CN2020128783W WO2021093865A1 WO 2021093865 A1 WO2021093865 A1 WO 2021093865A1 CN 2020128783 W CN2020128783 W CN 2020128783W WO 2021093865 A1 WO2021093865 A1 WO 2021093865A1
Authority
WO
WIPO (PCT)
Prior art keywords
negative electrode
electrode material
silicon
silicon oxide
lithium
Prior art date
Application number
PCT/CN2020/128783
Other languages
English (en)
French (fr)
Inventor
邓志强
屈丽娟
庞春雷
任建国
贺雪琴
Original Assignee
贝特瑞新材料集团股份有限公司
惠州市鼎元新能源科技有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 贝特瑞新材料集团股份有限公司, 惠州市鼎元新能源科技有限公司 filed Critical 贝特瑞新材料集团股份有限公司
Priority to US17/615,746 priority Critical patent/US20220328816A1/en
Priority to JP2021541129A priority patent/JP7236547B2/ja
Priority to EP20886472.8A priority patent/EP3965194A4/en
Priority to KR1020217022266A priority patent/KR20210104114A/ko
Publication of WO2021093865A1 publication Critical patent/WO2021093865A1/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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • 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
    • H01M4/36—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
    • H01M4/362—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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M4/624—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 application belongs to the technical field of energy storage materials, and relates to a negative electrode material, a preparation method thereof, and a lithium ion battery.
  • silicon-oxygen materials As a new type of negative electrode material for lithium-ion secondary batteries, silicon-oxygen materials have become a hot research topic due to their high capacity. However, compared with traditional graphite anode materials, the first-time Coulombic efficiency of silicon-oxygen materials is lower, and the cycle performance and rate performance are worse, which limits its commercial application.
  • SiO x When the silicon-oxygen material SiO x is charged for the first time, the oxygen atoms in SiO x will irreversibly react with Li+ in the electrolyte to form inert phases of Li 2 O and Li 4 SiO 4 , which intensifies its first irreversible capacity, resulting in SiO x For the first time, the coulombic efficiency of anode materials has decreased. Therefore, many researchers aim at this problem and use pre-replenishment of lithium to improve it.
  • a negative active material containing SiO x and Li 2 Si 2 O 5 improves cycle performance and initial charge-discharge characteristics.
  • Another Li-containing silicon oxide powder contains crystalline Li 2 Si 2 O 5 and Li 2 Si 2 O 3 to improve the cycle characteristics of the material.
  • Another negative electrode material containing SiO x , Li 2 Si 2 O 5 and Li 2 Si 2 O 3 can obtain good cycle characteristics and initial charge-discharge characteristics.
  • the lithium silicate in the above-mentioned negative electrode material will also promote the growth of silicon crystal grains during the crystallization process, and the increase of silicon crystal grains will affect the cycle performance of the negative electrode material.
  • the purpose of this application is to provide a negative electrode material, a preparation method thereof, and a lithium ion battery.
  • the negative electrode material provided in the present application controls the crystal grain size of lithium silicate, and finally enables the negative electrode material to obtain a high first-time coulombic efficiency while improving the cycle performance of the material.
  • the present application provides a negative electrode material
  • the negative electrode material includes nano silicon, silicon oxide, and crystalline Li 2 Si 2 O 5 , wherein the average particle size of Li 2 Si 2 O 5 crystal grains is less than 20 nm .
  • the size of the crystalline lithium silicate is within a suitable range, which improves the first-time Coulombic efficiency and cycle performance of the material.
  • lithium silicate has good lithium ion conductivity characteristics combined with its smaller crystal grains. The size can better ensure the smooth completion of the lithium ion insertion/de-lithium reaction, showing good rate performance.
  • the negative electrode material satisfies at least one of the following conditions a to f:
  • the chemical formula of the silicon oxide is SiO x , where 0 ⁇ x ⁇ 1;
  • the silicon oxide and the Li 2 Si 2 O 5 are dispersed with the nano silicon;
  • the Li 2 Si 2 O 5 covers at least part of the nano silicon and/or the silicon oxide
  • the particle size of the nano-silicon is 0-15nm and does not contain 0nm;
  • the mass fraction of Li 2 Si 2 O 5 in the negative electrode material is 30wt% to 70wt%;
  • the average particle size of the negative electrode material is 1 ⁇ m to 50 ⁇ m.
  • the negative electrode material satisfies at least one of the following conditions a to c:
  • a carbon coating layer is formed on the surface of the negative electrode material
  • a carbon coating layer is formed on the surface of the negative electrode material, and the thickness of the carbon coating layer is 10 nm to 2000 nm;
  • a carbon coating layer is formed on the surface of the negative electrode material, and the mass fraction of the carbon coating layer in the negative electrode material is 1 wt% to 10 wt%.
  • this application provides a method for preparing a negative electrode material, which includes the following steps:
  • the negative electrode material includes nano-silicon, silicon oxide, and crystalline Li 2 Si 2 O 5 .
  • the silicon-oxygen material is subjected to a suitable degree of heat treatment to disproportionate the silicon-oxygen material, and the reaction rate of the lithium doping reaction is controlled, thereby controlling the grain size of the lithium silicate produced, and greatly improving the first coulombic of the material.
  • the efficiency enables the negative electrode material to obtain high first-time Coulombic efficiency while improving the cycle performance of the negative electrode material.
  • lithium silicate has good lithium ion conductivity, combined with its smaller crystal grain size, to better ensure that lithium ions complete the lithium insertion/delithiation reaction smoothly, and exhibit good rate performance.
  • the negative electrode material satisfies at least one of the following conditions a to f:
  • the average particle size of the Li 2 Si 2 O 5 is less than 20 nm;
  • the chemical formula of the silicon oxide is SiO x , where 0 ⁇ x ⁇ 1;
  • the silicon oxide and the Li 2 Si 2 O 5 are dispersed with the nano silicon;
  • the particle size of the nano-silicon is 0-15nm and does not contain 0nm;
  • the mass fraction of Li 2 Si 2 O 5 in the negative electrode material is 30wt% to 70wt%;
  • the average particle size of the negative electrode material is 1 ⁇ m to 50 ⁇ m.
  • the method satisfies at least one of the following conditions a to g:
  • the chemical formula of the silicon-oxygen material is SiO y , where 0 ⁇ y ⁇ 2;
  • the silicon-oxygen material is silicon oxide
  • the surface of the silicon-oxygen material is covered with a carbon coating layer
  • the surface of the silicon-oxygen material is coated with a carbon coating layer, and the thickness of the carbon coating layer is 10 nm to 2000 nm;
  • the protective atmosphere includes at least one of nitrogen, helium, neon, argon, krypton and xenon;
  • the temperature of the heat treatment is 600°C ⁇ 1000°C;
  • the heat treatment time is 4h-10h.
  • the method satisfies at least one of the following conditions a to d:
  • the lithium source includes at least one of metallic lithium, lithium carbonate, lithium hydroxide, and lithium acetate;
  • the molar ratio of the heat-treated silicon-oxygen material to the lithium source is (1.5-7):1;
  • the sintering temperature is 300°C ⁇ 900°C;
  • the sintering time is 2h-8h.
  • the method further includes: after sintering, post-processing the sintered product, and the post-processing includes at least one of water washing and acid washing.
  • the method further includes:
  • the silicon-oxygen material is coated with carbon, and the carbon coating includes at least one of gas-coated carbon and solid-phase carbon-coated.
  • the method satisfies at least one of the following conditions a to b:
  • the carbon coating includes gas-phase carbon-coated, and the conditions for the gas-phase carbon-coated carbon are: the silicon oxide is heated to 600°C to 1000°C in a protective atmosphere, an organic carbon source gas is introduced, and the temperature is maintained for 0.5h Cool after ⁇ 10h; wherein, the organic carbon source gas includes hydrocarbons, and the hydrocarbons include at least one of methane, ethylene, acetylene, and benzene;
  • the carbon coating includes solid-phase carbon-coated, and the solid-phase carbon-coated condition is: after the silicon oxide and the carbon source are fused for 0.5h-2h, the resulting carbon mixture is heated at 600°C to 1000°C Carbonizing for 2h-6h, cooling; wherein, the carbon source includes at least one of polymers, sugars, organic acids, and pitch.
  • the method includes the following steps:
  • the silicon oxide is heat treated in a protective atmosphere or vacuum, the heat treatment temperature is 700°C to 900°C, and the heat treatment time is 4h to 10h to obtain the heat treated silicon oxide;
  • the molar ratio is (2.5 ⁇ 5):1.
  • the heat-treated silicon oxide is mixed with the lithium source, it is sintered.
  • the sintering temperature is 500°C ⁇ 800°C, and the sintering time For 2h-8h, the sintered product is washed with water and/or acid washed to obtain the negative electrode material.
  • the present application provides a lithium ion battery, the lithium ion battery comprising the above-mentioned negative electrode material or the negative electrode material prepared according to the above-mentioned preparation method.
  • the anode material provided by the present application greatly improves the first-time Coulombic efficiency of the material by doping the silicon oxide material with lithium, and by controlling the crystal grain size of the lithium silicate produced, the material can finally achieve a high first-time
  • the Coulomb efficiency also improves the cycle performance of the material.
  • lithium silicate has good lithium ion conductivity, combined with its smaller crystal grain size, to better ensure that lithium ions complete the lithium insertion/delithiation reaction smoothly, and exhibit good rate performance.
  • the preparation method provided in this application controls the reaction rate of the lithium doping reaction by disproportionating the silicon-oxygen material to a suitable degree, thereby controlling the crystal grain size of the lithium silicate produced, ensuring the performance of the product, and obtaining The high first-time coulombic efficiency also improves the cycle performance of the material.
  • FIG. 1 is a process flow diagram of a method for preparing a negative electrode material provided by an embodiment of the application
  • FIG. 3 is an SEM image of the negative electrode material prepared in Example 2 of the application.
  • the present application provides a negative electrode material
  • the negative electrode material includes nano silicon, silicon oxide, and crystalline Li 2 Si 2 O 5 , wherein the average particle size of Li 2 Si 2 O 5 crystal grains is less than 20 nm .
  • the negative electrode material provided in this application contains Li 2 Si 2 O 5 as a lithium silicate phase. Since Li 2 Si 2 O 5 is insoluble in water, it can fundamentally solve the problem of the processing stability of the negative electrode material, such as slurry production. Low gas and viscosity, tailing during coating, pinholes, pores, etc. appear after the pole piece is dried. There is no need for additional surface treatment of the negative electrode material, which can avoid the problems of reduced capacity and reduced first efficiency of lithium batteries due to surface treatment.
  • the average particle size of Li 2 Si 2 O 5 crystal grains is less than 20 nm, and specifically can be 19 nm, 18 nm, 17 nm, 16 nm, 15 nm, 14 nm, 13 nm, 12 nm, 11 nm, 10 nm, 9 nm, 8 nm, 6nm or 5nm, etc.
  • the average particle size is controlled within 20 nm, and the negative electrode material exhibits good cycle performance and rate performance. If the crystal grains are too large, the cycle performance and rate performance of the negative electrode material will deteriorate.
  • the chemical formula of the silicon oxide is SiO x , where 0 ⁇ x ⁇ 1, and SiO x may specifically be SiO 0.1 , SiO 0.2 , SiO 0.3 , SiO 0.4 , SiO 0.5 , SiO 0.6 , SiO 0.7 , SiO 0.8 , SiO 0.9 or SiO etc.
  • SiO x is SiO. It should be noted that the composition of SiO x is relatively complicated and can be understood as being formed by uniformly dispersing silicon element Si in SiO 2 .
  • the average particle size of the negative electrode material is 1 ⁇ m-50 ⁇ m; more specifically, it can be 1 ⁇ m, 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 25 ⁇ m, 30 ⁇ m, 35 ⁇ m, 40 ⁇ m, or 50 ⁇ m, etc., but is not limited to For the listed values, other unlisted values within the range of values are also applicable.
  • the average particle size of the silicon composite anode material is controlled within the above range, which is beneficial to the improvement of the cycle performance of the anode material.
  • the silicon oxide and the Li 2 Si 2 O 5 is dispersed in the nano-silicon, and more specifically, the silicon oxide and the Li 2 Si 2 O 5 in The nano silicon is uniformly dispersed; or, the nano silicon is dispersed in silicon oxide, and Li 2 Si 2 O 5 covers at least part of the nano silicon and/or silicon oxide.
  • the average particle diameter of the nano-silicon is 0-15 nm and does not include 0 nm, such as 1 nm, 3 nm, 5 nm, 8 nm, 10 nm, 12 nm, or 15 nm. Controlling the nano-silicon within the above range can help improve the cycle performance and rate performance of the negative electrode material.
  • the mass fraction of Li 2 Si 2 O 5 in the negative electrode material is 30wt% to 70wt%, specifically may be 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt%, 60wt%, 65wt% or 70wt%, etc., but not limited to the listed values, and other unlisted values within this range of values are also applicable. Controlling the mass fraction of Li 2 Si 2 O 5 within the above range can help increase the capacity and first-time coulombic efficiency of the negative electrode material.
  • a carbon coating layer is further formed on the surface of the negative electrode material.
  • the mass fraction of the carbon coating layer in the negative electrode material is 1wt% to 10wt%, and specifically can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%, etc., but not limited to the listed values, and other unlisted values within this range of values are also applicable.
  • the thickness of the carbon coating layer is 10 nm to 2000 nm, more specifically, it can be 10 nm, 50 nm, 100 nm, 300 nm, 500 nm, 800 nm, 1000 nm, 1500 nm, 1800 nm or 2000 nm, but it is not limited to the listed values. Other unlisted values in the range also apply. If the carbon layer is too thick, the lithium ion transmission efficiency is reduced, which is not conducive to the large-rate charge and discharge of the material, and the overall performance of the negative electrode material is reduced. Lead to long cycle performance price difference.
  • this application provides a method for preparing a negative electrode material, which includes the following steps:
  • the negative electrode material includes nano-silicon, silicon oxide, and crystalline Li 2 Si 2 O 5 .
  • the preparation method provided in this application greatly improves the first coulombic efficiency of the negative electrode material by doping the silicon-oxygen material with lithium, and controls the lithium doping by disproportionating the silicon-oxygen material (such as silicon oxide) to a suitable degree.
  • the reaction rate of the reaction thereby controlling the crystal grain size of the lithium silicate produced, finally enables the negative electrode material to obtain a high first-time coulombic efficiency while improving the cycle performance of the negative electrode material.
  • Li 2 Si 2 O 5 has good lithium ion conductivity, combined with its smaller crystal grain size, to better ensure that lithium ions complete the lithium insertion/delithiation reaction smoothly, and exhibit good rate performance.
  • the chemical formula of the silicon-oxygen material is SiO y , where 0 ⁇ y ⁇ 2, and SiO y may specifically be SiO 0.1 , SiO 0.2 , SiO 0.5 , SiO 0.7 , SiO, SiO 1.2 , SiO 1.4 , SiO 1.6 , SiO 1.8 or SiO 1.9 etc.
  • the composition of SiO y is relatively complicated and can be understood as being formed by uniformly dispersing amorphous silicon elemental Si in SiO 2 . At high temperatures, its thermodynamic properties are very unstable, and it is prone to disproportionation to produce Si and SiO 2 .
  • the average particle size of the silica material is 1 ⁇ m-50 ⁇ m, more specifically, more specifically, may be 1 ⁇ m, 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 25 ⁇ m, 30 ⁇ m, 35 ⁇ m, 40 ⁇ m, or 50 ⁇ m.
  • Etc., controlling the silicon-oxygen material within the above range can improve the cycle performance and rate performance of the negative electrode material.
  • the protective atmosphere includes at least one of nitrogen, helium, neon, argon, krypton, and xenon.
  • the temperature of the heat treatment is 600°C to 1000°C, specifically 600°C, 700°C, 800°C, 900°C, or 1000°C, etc., but it is not limited to the listed values, and there are other unlisted values within this range of values.
  • the numerical values also apply, optionally, the temperature of the heat treatment is 700°C to 900°C.
  • the heat treatment time is 4h-10h, specifically 4h, 5h, 6h, 7h, 8h, 9h or 10h, etc., but it is not limited to the listed values, and other unlisted values within the range of values The same applies.
  • the heat treatment time increases, the amount of nano-silicon gradually increases, but the particle size of nano-silicon does not change much, so that the silicon oxide material is fully disproportionated to produce sufficient amount
  • the nano silicon is beneficial to improve the electrochemical performance of the negative electrode material.
  • the silicon-oxygen material can be fully disproportionated, that is, the silicon-oxygen material itself undergoes an oxidation-reduction reaction, and the disproportionation generates nano-silicon, which is beneficial to improve the electrochemical performance of the anode material.
  • the silicon oxide material may be silicon oxide SiO.
  • the method before the silicon-oxygen material is heat-treated, the method further includes:
  • the silicon-oxygen material is coated with carbon, and the carbon coating includes at least one of gas-coated carbon and solid-phase carbon-coated.
  • carbon coating is performed on the silicon-oxygen material because the carbon layer is relatively loose and there are a large number of micropores, and the subsequent lithium salt can penetrate the carbon coating layer through the micropores of the carbon coating layer.
  • the reaction is carried out on the surface of the silicon-oxygen material, and the carbon coating layer in the obtained negative electrode material is still located in the outermost layer.
  • the silicon-oxygen material is heated to 600°C to 1000°C in a protective atmosphere, and an organic carbon source gas is introduced, and the temperature is kept for 0.5h to 10h and then cooled.
  • the organic carbon source gas includes hydrocarbons, and the hydrocarbons include at least one of methane, ethylene, acetylene, and benzene.
  • the resulting carbon mixture is carbonized at 600°C ⁇ 1000°C for 2h-6h, and cooled .
  • the carbon source includes at least one of polymers, sugars, organic acids, and pitch.
  • the lithium source includes at least one of metallic lithium, lithium carbonate, lithium hydroxide, or lithium acetate.
  • the molar ratio of the heat-treated silicon-oxygen material to the lithium source is (1.5-7):1, and specifically may be 1.5:1, 2:1, 3:1, 4:1 , 5:1, 6:1 or 7:1, etc., but not limited to the listed values, and other unlisted values within this range of values are also applicable.
  • the processing performance results in a lower first effect of the negative electrode material; when the molar ratio of the silicon-oxygen material to the lithium source is too low (that is, there are too many lithium sources), an ideal negative electrode material cannot be obtained.
  • the molar ratio of the heat-treated silicon-oxygen material to the lithium source is (2.5-5):1.
  • the mixing is performed in a mixing device.
  • the protective atmosphere includes at least one of nitrogen, helium, neon, argon, krypton, and xenon.
  • the sintering temperature is 300°C to 900°C, specifically 300°C, 400°C, 500°C, 600°C, 700°C, 800°C or 900°C, etc., but is not limited to the listed values. Other unlisted values within this value range are also applicable, and can be selected from 500°C to 800°C.
  • the sintering temperature is too high, the reaction will be violent, and the silicon crystal grains will grow up sharply, which will affect the cycle performance of the negative electrode material; when the sintering temperature is too low, Li 2 Si 2 O 5 cannot be formed.
  • the sintering time is 2h to 8h, more specifically, it can be 2h, 3h, 4h, 5h, 6h, 7h, or 8h, etc., but it is not limited to the listed values, and other values within this range are not limited.
  • the enumerated values are also applicable, and it is understood that full sintering can fully react the silicon oxide with the lithium source to form Li 2 Si 2 O 5 .
  • the method further includes: performing post-treatment on the sintered product after sintering, and the post-treatment includes at least one of water washing and acid washing.
  • the sintered product may contain water-soluble lithium-containing compounds such as Li 2 O, Li 4 SiO 4 , Li 2 Si 2 O 3 , and Li 2 Si 2 O 5 is insoluble in water, and impurities in the sintered product can be removed by washing with water. Similarly, these impurity phases can also be removed by pickling, thereby improving the first effect and cycle stability of the negative electrode material.
  • the acid solution may be, for example, hydrochloric acid, nitric acid, or sulfuric acid.
  • the method includes the following steps:
  • the silicon oxide is heat treated in a protective atmosphere or vacuum, the heat treatment temperature is 700°C to 900°C, and the heat treatment time is 4h to 10h to obtain the heat treated silicon oxide;
  • the molar ratio is (2.5 ⁇ 5):1.
  • the heat-treated silicon oxide is mixed with the lithium source, it is sintered.
  • the sintering temperature is 500°C ⁇ 800°C, and the sintering time For 2h-8h, the sintered product is washed with water and/or acid washed to obtain the negative electrode material.
  • the present application provides a lithium ion battery, the lithium ion battery comprising the silicon-oxygen composite negative electrode material described in the first aspect or the silicon-oxygen composite negative electrode material obtained by the preparation method described in the second aspect.
  • the negative electrode material was prepared according to the following method:
  • the silicon oxide containing lithium inside is sintered at 600° C. for 6 hours, and the sintered product is pickled to obtain a negative electrode material.
  • the negative electrode material prepared in this embodiment includes nano-silicon, silicon oxide SiO 0.2 and crystalline Li 2 Si 2 O 5.
  • the nano-silicon is uniformly dispersed in SiO 0.2 and Li 2 Si 2 O 5.
  • the average particle size of the nano-silicon The average particle size of Li 2 Si 2 O 5 crystal grains is 18.3 nm, and the mass fraction of Li 2 Si 2 O 5 in the negative electrode material is 67 wt %.
  • a carbon coating layer is formed on the surface of the negative electrode material.
  • Figure 2 is an SEM image of the negative electrode material prepared in this embodiment.
  • the negative electrode material was prepared according to the following method:
  • the silicon oxide containing lithium is sintered at 600° C. for 6 hours, and the sintered product is pickled to obtain a negative electrode material.
  • the negative electrode material prepared in this embodiment includes nano-silicon, silicon oxide SiO 0.3 and crystalline Li 2 Si 2 O 5.
  • the nano-silicon is uniformly dispersed in SiO 0.3 and Li 2 Si 2 O 5.
  • the average particle size of the nano-silicon The average particle size of Li 2 Si 2 O 5 crystal grains is 10.4 nm, and the mass fraction of Li 2 Si 2 O 5 in the negative electrode material is 56 wt %.
  • a carbon coating layer is formed on the surface of the negative electrode material.
  • FIG. 3 is an SEM image of the negative electrode material prepared in this embodiment.
  • the negative electrode material was prepared according to the following method:
  • the silicon oxide containing lithium inside is sintered at 800° C. for 8 hours, and the sintered product is pickled to obtain a negative electrode material.
  • the negative electrode material prepared in this embodiment includes nano-silicon, silicon oxide SiO 0.7 and crystalline Li 2 Si 2 O 5.
  • the nano-silicon is uniformly dispersed in SiO 0.7 and Li 2 Si 2 O 5.
  • the average particle size of the nano-silicon The average particle size of Li 2 Si 2 O 5 crystal grains is 11.6 nm, and the mass fraction of Li 2 Si 2 O 5 in the negative electrode material is 37 wt %.
  • a carbon coating layer is formed on the surface of the negative electrode material.
  • the negative electrode material was prepared according to the following method:
  • the silicon oxide containing lithium inside is sintered at 500° C. for 8 hours, and the sintered product is washed with water to obtain a negative electrode material.
  • the negative electrode material prepared in this embodiment includes nano-silicon, silicon oxide SiO 0.8 and crystalline Li 2 Si 2 O 5.
  • the nano-silicon is uniformly dispersed in SiO 0.8 and Li 2 Si 2 O 5.
  • the average particle size of the nano-silicon The average particle size of Li 2 Si 2 O 5 crystal grains is 10.7 nm, and the mass fraction of Li 2 Si 2 O 5 in the negative electrode material is 33 wt %.
  • a carbon coating layer is formed on the surface of the negative electrode material.
  • the anode material was prepared according to the following method:
  • the silicon oxide containing lithium inside is sintered at 300°C for 6 hours, and the sintered product is pickled to obtain a negative electrode material.
  • the negative electrode material prepared in this embodiment includes nano silicon, silicon oxide SiO 0.9 and crystalline Li 2 Si 2 O 5.
  • the nano silicon is uniformly dispersed in SiO 0.9 and Li 2 Si 2 O 5.
  • the average particle size of the nano silicon The average particle size of Li 2 Si 2 O 5 crystal grains is 6.8 nm, and the mass fraction of Li 2 Si 2 O 5 in the negative electrode material is 30 wt %.
  • a carbon coating layer is formed on the surface of the negative electrode material.
  • the negative electrode material was prepared according to the following method:
  • the silicon oxide containing lithium inside is sintered at 900° C. for 6 hours, and the sintered product is pickled to obtain a negative electrode material.
  • the negative electrode material prepared in this embodiment includes nano-silicon, silicon oxide SiO 0.3 and crystalline Li 2 Si 2 O 5.
  • the nano-silicon is uniformly dispersed in SiO 0.3 and Li 2 Si 2 O 5.
  • the average particle size of the nano-silicon The average particle size of Li 2 Si 2 O 5 crystal grains is 12.2 nm, and the mass fraction of Li 2 Si 2 O 5 in the negative electrode material is 61 wt %.
  • a carbon coating layer is formed on the surface of the negative electrode material.
  • step (1) except that the heat treatment temperature in step (1) is 570° C., other operating conditions and materials are the same as those in embodiment 1.
  • the negative electrode material prepared in this embodiment includes nano silicon, silicon oxide SiO 0.4 and crystalline Li 2 Si 2 O 5.
  • the nano silicon is uniformly dispersed in SiO 0.4 and Li 2 Si 2 O 5.
  • the average particle size of the nano silicon is The average particle size of Li 2 Si 2 O 5 crystal grains is 26.5 nm, and the mass fraction of Li 2 Si 2 O 5 in the negative electrode material is 58 wt %.
  • a carbon coating layer is formed on the surface of the negative electrode material.
  • step (1) except that the heat treatment temperature in step (1) is 1025° C., other operating conditions and materials are the same as those in Embodiment 1.
  • the negative electrode material prepared in this embodiment includes nano-silicon, silicon oxide SiO 0.3 and crystalline Li 2 Si 2 O 5.
  • the nano-silicon is uniformly dispersed in SiO 0.3 and Li 2 Si 2 O 5.
  • the average particle size of the nano-silicon The average particle size of Li 2 Si 2 O 5 crystal grains is 17.6 nm, and the mass fraction of Li 2 Si 2 O 5 in the negative electrode material is 45% by weight.
  • the negative electrode material is also coated with a carbon layer on the surface.
  • the negative electrode material was prepared according to the following method:
  • the negative electrode material prepared in this embodiment includes heat-treated silicon oxide, and does not contain nano-silicon and Li 2 Si 2 O 5 .
  • the negative electrode material was prepared according to the following method:
  • the silicon oxide containing lithium inside is sintered at 600° C. for 6 hours, and the sintered product is pickled to obtain a negative electrode material.
  • the negative electrode material prepared in this embodiment includes nano-silicon, silicon oxide SiO 0.2 and crystalline Li 2 Si 2 O 5.
  • the nano-silicon is uniformly dispersed in SiO 0.2 and Li 2 Si 2 O 5.
  • the average particle size of the nano-silicon The average particle size of Li 2 Si 2 O 5 crystal grains is 27.4 nm, and the mass fraction of Li 2 Si 2 O 5 in the negative electrode material is 67 wt %.
  • a carbon coating layer is formed on the surface of the negative electrode material.
  • Table 1 shows the test results and performance characterization results of the Li 2 Si 2 O 5 grain size of the negative electrode material prepared in this comparative example.
  • the negative electrode material powder prepared in each example and comparative example was subjected to X-ray diffraction measurement using CuK ⁇ rays, and the analysis of the diffraction angle 2 ⁇ showed that the (111) peak attributable to Li 2 Si 2 O 5 was in the range of 24.4°-25.0°.
  • the crystal grain value of Li 2 Si 2 O 5 is calculated by Scherrer's formula.
  • Example 7 The heat treatment temperature of Example 7 was too low, which caused the crystal grains of Li 2 Si 2 O 5 to be too large, resulting in poor cycle retention and capacity retention.
  • Example 8 The heat treatment temperature of Example 8 is too high, resulting in an inappropriate degree of disproportionation of the silicon-oxygen material, and the capacity and first effect of the material are both low.
  • the silicon oxide material was not doped with lithium, resulting in a lower first effect of the material.
  • the anode materials of Examples 1-6 greatly improve the first coulombic efficiency of the material by doping the silicon oxide material with lithium, and by controlling the generated Li 2 Si 2 O 5
  • the crystal grain size makes the average grain size of the crystal grains less than 20nm, which finally enables the material to obtain high first coulombic efficiency while improving the cycle performance of the material.
  • Li 2 Si 2 O 5 has good lithium ion conductivity characteristics, combined with its smaller crystal grain size, to better ensure that lithium ions complete the lithium insertion/delithiation reaction smoothly, and exhibit good rate performance.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Silicon Compounds (AREA)
  • Silicates, Zeolites, And Molecular Sieves (AREA)

Abstract

一种负极材料及其制备方法和锂离子电池。所述负极材料包括纳米硅、硅氧化物和晶质的Li 2Si 2O 5，其中，Li 2Si 2O 5的平均粒径小于20nm。所述制备方法包括：在保护性气氛或真空下对硅氧材料进行热处理，得到热处理后的硅氧材料(S100)；在保护性气氛或真空下将所述热处理后的硅氧材料与锂源混合后，进行烧结，得到负极材料，所述负极材料包括纳米硅、硅氧化物和晶质的Li 2Si 2O 5(S200)。负极材料通过对硅氧材料进行锂掺杂，大幅提高了材料的首次库伦效率，并且通过控制生成的硅酸锂的晶粒尺寸，最终使材料在获得高的首次库伦效率的同时，提高了材料的循环性能。将硅酸锂制备成较小的晶粒尺寸，更好地保证锂离子顺畅地完成嵌/脱锂反应，表现出良好的倍率性能。

Description

一种负极材料及其制备方法和锂离子电池
本申请要求于2019年11月14日提交中国专利局，申请号为2019111126773、发明名称为“一种负极材料及其制备方法和锂离子电池”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请属于储能材料技术领域，涉及一种负极材料及其制备方法和锂离子电池。
背景技术
作为一种新型的锂离子二次电池负极材料，硅氧材料因容量高而成为现今研究的热点。但是相比传统的石墨负极材料，硅氧材料的首次库伦效率较低，循环性能和倍率性能更差，因而限制了它的商业化应用。
硅氧材料SiO x在首次充电时，SiO x中的氧原子也会和电解液中的Li+发生不可逆反应生成惰性相的Li 2O和Li 4SiO 4，加剧了其首次不可逆容量，导致SiO x负极材料首次库伦效率的下降。因此，许多的研究者针对这一问题，使用预先补锂的方式进行改善。
一种含有SiO x以及Li 2Si 2O 5的负极活性材料，提高了循环性能和初始充放电特性。又一种含Li氧化硅粉末，含有晶态Li 2Si 2O 5和Li 2Si 2O 3，改善了材料的循环特性。另一种负极含有SiO x、Li 2Si 2O 5和Li 2Si 2O 3的负极材料，可以获得良好的循环特性和初期充放电特性。
但是，上述负极材料中的硅酸锂在晶化过程中，也会促进硅的晶粒长大，硅晶粒增大会影响负极材料的循环性能。
申请内容
针对现有技术存在的上述问题，本申请的目的在于提供一种负极材料及其制备方法和锂离子电池。本申请提供的负极材料通过控制硅酸锂的晶粒尺寸，最终使负极材料在获得高的首次库伦效率的同时，提高了材料的循环性能。
为达此目的，本申请采用以下技术方案：
第一方面，本申请提供一种负极材料，所述负极材料包括纳米硅、硅氧化物和晶质的Li 2Si 2O 5，其中，Li 2Si 2O 5晶粒的平均粒径小于20nm。
在上述方案中，晶质的硅酸锂的尺寸在合适的范围内，提高材料首次库伦效率及循环性能，另一方面，硅酸锂具有良好的锂离子传导特性，结合其较小的晶粒尺寸，更好地保证锂离子顺畅地完成嵌/脱锂反应，表现出良好的倍率性能。
在一种可行的实施方式中，所述负极材料满足以下条件a～f的至少一者：
a.所述硅氧化物的化学式为SiO x，其中，0＜x≤1；
b.所述硅氧化物和所述Li 2Si 2O 5中分散有所述纳米硅；
c.所述Li 2Si 2O 5包覆至少部分所述纳米硅和/或所述硅氧化物；
d.所述纳米硅的粒径为0～15nm且不包含0nm；
e.所述负极材料中的Li 2Si 2O 5的质量分数为30wt％～70wt％；
f.所述负极材料的平均粒径为1μm～50μm。
在一种可行的实施方式中，所述负极材料满足以下条件a～c的至少一者：
a.所述负极材料表面形成有碳包覆层；
b.所述负极材料表面形成有碳包覆层，所述碳包覆层的厚度为10nm～2000nm；
c.所述负极材料表面形成有碳包覆层，所述负极材料中的碳包覆层的质量分数为1wt％～10wt％。
第二方面，本申请提供一种负极材料的制备方法，包括以下步骤：
在保护性气氛或真空下对硅氧材料进行热处理，得到热处理后的硅氧材料；
在保护性气氛或真空下将所述热处理后的硅氧材料与锂源混合后，进行烧结，得到负极材料，所述负极材料包括纳米硅、硅氧化物和晶质的Li 2Si 2O 5。
在上述方案中，通过对硅氧材料进行合适程度热处理，使得硅氧材料歧化，控制了锂掺杂反应的反应速率，从而控制生成的硅酸锂的晶粒尺寸，大幅提高了材料的首次库伦效率，使得负极材料在获得高的首次库伦效率的同时，提高负极材料的循环性能。此外，硅酸锂具有良好的锂离子传导特性，结合其较小的晶粒尺寸，更好地保证锂离子顺畅地完成嵌/脱锂反应，表现出良好的倍率性能。
在一种可行的实施方式中，所述负极材料满足以下条件a～f的至少一者：
a.所述Li 2Si 2O 5的平均粒径小于20nm；
b.所述硅氧化物的化学式为SiO x，其中，0＜x≤1；
c.所述硅氧化物和所述Li 2Si 2O 5中分散有所述纳米硅；
d.所述纳米硅的粒径为0～15nm且不包含0nm；
e.所述负极材料中的Li 2Si 2O 5的质量分数为30wt％～70wt％；
f.所述负极材料的平均粒径为1μm～50μm。
在一种可行的实施方式中，所述方法满足以下条件a～g的至少一者：
a.所述硅氧材料的化学式为SiO y，其中，0＜y＜2；
b.所述硅氧材料为氧化亚硅；
c.所述硅氧材料的表面包覆有碳包覆层；
d.所述硅氧材料的表面包覆有碳包覆层，所述碳包覆层的厚度为10nm～2000nm；
e.所述保护性气氛包括氮气、氦气、氖气、氩气、氪气和氙气中的至少一种；
f.所述热处理的温度为600℃～1000℃；
g.所述热处理的时间为4h～10h。
在一种可行的实施方式中，所述方法满足以下条件a～d的至少一者：
a.所述锂源包括金属锂、碳酸锂、氢氧化锂和醋酸锂中的至少一种；
b.所述热处理后的硅氧材料与所述锂源的摩尔比为(1.5～7):1；
c.所述烧结的温度为300℃～900℃；
d.所述烧结的时间为2h～8h。
在一种可行的实施方式中，所述方法还包括：在烧结后，对烧结产品进行后处 理，所述后处理包括水洗和酸洗中的至少一种。
在一种可行的实施方式中，所述方法还包括：
对硅氧材料进行碳包覆，所述碳包覆包括气相包碳和固相包碳中的至少一种。
在一种可行的实施方式中，所述方法满足以下条件a～b的至少一者：
a.所述碳包覆包括气相包碳，所述气相包碳的条件为：将所述硅氧化物在保护性气氛下升温至600℃～1000℃，通入有机碳源气体，保温0.5h～10h后冷却；其中，所述有机碳源气体包括烃类，所述烃类包括甲烷、乙烯、乙炔和苯中的至少一种；
b.所述碳包覆包括固相包碳，所述固相包碳的条件为：将所述硅氧化物与碳源融合0.5h～2h后，将得到的碳混合物在600℃～1000℃下碳化2h～6h，冷却；其中，所述碳源包括聚合物、糖类、有机酸和沥青中的至少一种。
在一种可行的实施方式中，所述方法包括以下步骤：
在保护性气氛或真空下对氧化亚硅进行热处理，热处理温度为700℃～900℃，热处理时间为4h～10h，得到热处理后的氧化亚硅；
在保护性气氛或真空下，按照摩尔比为(2.5～5)：1将所述热处理后的氧化亚硅与锂源混合后，进行烧结，烧结的温度为500℃～800℃，烧结的时间为2h～8h，对烧结产品进行水洗和/或酸洗，得到负极材料。
第三方面，本申请提供一种锂离子电池，所述锂离子电池包含上述的负极材料或根据上述的制备方法制得的负极材料。
与现有技术相比，本申请具有以下有益效果：
(1)本申请提供的负极材料通过对氧化亚硅材料进行锂掺杂，大幅提高了材料的首次库伦效率，并且通过控制生成的硅酸锂的晶粒尺寸，最终使材料在获得高的首次库伦效率的同时，提高了材料的循环性能。此外，硅酸锂具有良好的锂离子传导特性，结合其较小的晶粒尺寸，更好地保证锂离子顺畅地完成嵌/脱锂反应，表现出良好的倍率性能。
(2)本申请提供的制备方法通过对硅氧材料进行合适程度的歧化，控制了锂掺杂反应的反应速率，从而控制生成的硅酸锂的晶粒尺寸，保证了产品的性能，在获得高的首次库伦效率的同时，提高了材料的循环性能。
附图说明
图1为本申请实施例提供的一种负极材料的制备方法的工艺流程图；
图2为本申请实施例1制备的负极材料的SEM图；
图3为本申请实施例2制备的负极材料的SEM图。
具体实施方式
为更好地说明本申请，便于理解本申请的技术方案，下面对本申请进一步详细说明。但下述的实施例仅仅是本申请的简易例子，并不代表或限制本申请的权利保护范围，本申请保护范围以权利要求书为准。
以下为本申请典型但非限制性实施例：
第一方面，本申请提供一种负极材料，所述负极材料包括纳米硅、硅氧化物和 晶质的Li 2Si 2O 5，其中，Li 2Si 2O 5晶粒的平均粒径小于20nm。
本申请提供的负极材料中含有Li 2Si 2O 5这一种硅酸锂相，由于Li 2Si 2O 5不溶于水，可从根本上解决负极材料的加工稳定性问题，如浆料产气、粘度低，涂布时拖尾，极片干燥后出现针孔、气孔等。不需要额外的对负极材料进行表面处理，可以避免锂电池因为表面处理带来的容量降低、首效降低等问题。
以下作为本申请可选的技术方案，但不作为对本申请提供的技术方案的限制，通过以下可选的技术方案，可以更好的达到和实现本申请的技术目的和有益效果。
本申请提供的负极材料中，Li 2Si 2O 5晶粒的平均粒径小于20nm，具体可以是19nm、18nm、17nm、16nm、15nm、14nm、13nm、12nm、11nm、10nm、9nm、8nm、6nm或5nm等。有益效果：平均粒径控制在20nm以内，负极材料表现出良好的循环性能和倍率性能，如果晶粒过大，会导致负极材料循环性能和倍率性能变差。
作为本申请可选的技术方案，所述硅氧化物的化学式为SiO x，其中，0＜x≤1，SiO x具体可以是SiO 0.1、SiO 0.2、SiO 0.3、SiO 0.4、SiO 0.5、SiO 0.6、SiO 0.7、SiO 0.8、SiO 0.9或SiO等。优选地，SiO x为SiO。需要说明的是，SiO x的组成比较复杂，可以理解为由硅单质Si均匀分散在SiO 2中形成。
作为本申请可选的技术方案，所述负极材料的平均粒径1μm～50μm；更具体地，可以是1μm、10μm、15μm、20μm、25μm、30μm、35μm、40μm或50μm等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。硅复合物负极材料的平均粒径控制在上述范围内，有利于负极材料循环性能的提升。
作为本申请可选的技术方案，所述硅氧化物和所述Li 2Si 2O 5中分散有所述纳米硅，更具体地，所述硅氧化物和所述Li 2Si 2O 5中均匀分散有所述纳米硅；或者，纳米硅分散于硅氧化物中，Li 2Si 2O 5包覆至少部分所述纳米硅和/或硅氧化物。
可选地，所述纳米硅的平均粒径为0～15nm且不包含0nm，例如1nm、3nm、5nm、8nm、10nm、12nm或15nm等。将纳米硅控制在上述范围内，能够有利于提高负极材料的循环性能、倍率性能。
可选地，所述负极材料中的Li 2Si 2O 5的质量分数为30wt％～70wt％，具体可以是30wt％、35wt％、40wt％、45wt％、50wt％、55wt％、60wt％、65wt％或70wt％等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。将Li 2Si 2O 5的质量分数控制在上述范围内，能够有利于提高负极材料的容量、首次库伦效率。
作为本申请可选的技术方案，所述负极材料表面还形成有碳包覆层。
所述负极材料中的碳包覆层的质量分数为1wt％～10wt％，具体可以是1wt％、2wt％、3wt％、4wt％、5wt％、6wt％、7wt％、8wt％、9wt％或10wt％等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。
所述碳包覆层的厚度为10nm～2000nm，更具体地，可以是10nm、50nm、100nm、300nm、500nm、800nm、1000nm、1500nm、1800nm或2000nm，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。碳层过厚，锂离子传输效率降低，不利于材料大倍率充放电，降低负极材料的综合性能，碳层过薄，不利于增加负极材料的导电性且对材料的体积膨胀抑制性能较弱，导致长循环性能价差。
第二方面，本申请提供一种负极材料的制备方法，包括以下步骤：
S100，在保护性气氛或真空下对硅氧材料进行热处理，得到热处理后的硅氧材料；
S200，在保护性气氛或真空下将所述热处理后的硅氧材料与锂源混合后，进行烧结，得到负极材料，所述负极材料包括纳米硅、硅氧化物和晶质的Li 2Si 2O 5。
本申请提供的制备方法通过对硅氧材料进行锂掺杂，大幅提高了负极材料的首次库伦效率，并且通过对硅氧材料(例如氧化亚硅)材料进行合适程度的歧化，控制了锂掺杂反应的反应速率，从而控制生成的硅酸锂的晶粒尺寸，最终使负极材料在获得高的首次库伦效率的同时，提高了负极材料的循环性能。并且，Li 2Si 2O 5具有良好的锂离子传导特性，结合其较小的晶粒尺寸，更好地保证锂离子顺畅地完成嵌/脱锂反应，表现出良好的倍率性能。
以下详细介绍本方案提供的制备方法：
S100，在保护性气氛或真空下对硅氧材料进行热处理，得到热处理后的硅氧材料。
作为本申请可选的技术方案，所述硅氧材料的化学式为SiO y，其中，0＜y＜2，SiO y具体可以是SiO 0.1、SiO 0.2、SiO 0.5、SiO 0.7、SiO、SiO 1.2、SiO 1.4、SiO 1.6、SiO 1.8或SiO 1.9等。需要说明的是，SiO y的组成比较复杂，可以理解为由无定型硅单质Si均匀分散在SiO 2中形成。在高温下，其热力学性质非常不稳定，容易发生歧化生成Si和SiO 2。
作为本申请可选的技术方案，所述硅氧材料的平均粒径为1μm～50μm，更具体地，更具体地，可以是1μm、10μm、15μm、20μm、25μm、30μm、35μm、40μm或50μm等，将硅氧材料控制在上述范围内，可以提高负极材料的循环性能与倍率性能。
作为本申请可选的技术方案，保护性气氛包括氮气、氦气、氖气、氩气、氪气和氙气中的至少一种。
可选地，热处理的温度为600℃～1000℃，具体可以是600℃、700℃、800℃、900℃或1000℃等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，可选地，热处理的温度为700℃～900℃。经过多次试验发现，热处理的温度过高，单晶硅的生长速率加快，颗粒尺寸也逐渐增大。热处理温度过低，歧化反应速率下降，影响硅氧材料的歧化程度。
可选地，所述热处理的时间为4h～10h，具体可以是4h、5h、6h、7h、8h、9h或10h等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。经过多次试验发现，在上述时间范围内，随着热处理时间增加，纳米硅的数量也逐渐增加，但纳米硅的颗粒尺寸不会发生太大的变化，从而使得硅氧材料充分歧化生成足量的纳米硅，有利于提高负极材料的电化学性能。
在本实施例中，通过热处理，可以使得硅氧材料进行充分的歧化，即使得硅氧材料自身发生氧化还原反应，歧化生成纳米硅，有利于提高负极材料的电化学性能。
作为本申请可选的技术方案，可选所述硅氧材料为氧化亚硅SiO。
作为本申请可选的技术方案，在对硅氧材料进行热处理之前，所述方法还包括：
对硅氧材料进行碳包覆，所述碳包覆包括气相包碳和固相包碳中的至少一种。
可以理解地，在所述硅氧材料进行碳包覆，因为碳层较为疏松，存在大量微孔道，而后续的锂盐可以通过碳包覆层的微孔道，渗透过碳包覆层而在硅氧材料表面进行反应，得到的负极材料中的碳包覆层依然是位于最外层。
作为本申请可选的技术方案，采用气相包碳时，将所述硅氧材料在保护性气氛下升温至600℃～1000℃，通入有机碳源气体，保温0.5h～10h后冷却。
在一些实施例中，所述有机碳源气体包括烃类，所述烃类包括甲烷、乙烯、乙炔和苯中的至少一种。
作为本申请可选的技术方案，采用固相包碳时，将所述硅氧材料与碳源融合0.5h～2h后，将得到的碳混合物在600℃～1000℃下碳化2h～6h，冷却。
在一些实施例中，所述碳源包括聚合物、糖类、有机酸和沥青中的至少一种。
S200，在保护性气氛或真空下将所述热处理后的硅氧材料与锂源混合后，进行烧结，得到负极材料。
作为本申请可选的技术方案，所述锂源包括金属锂、碳酸锂、氢氧化锂或醋酸锂中的至少一种。
作为本申请可选的技术方案，所述热处理后的硅氧材料与锂源的摩尔比为(1.5～7):1，具体可以是1.5:1、2:1、3:1、4:1、5:1、6:1或7:1等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。经过多次试验发现，当热处理后的硅氧材料和锂源的摩尔比过高(即硅氧材料过多)，会硅氧材料不能充分转化成Li 2Si 2O 5，从而影响负极材料的加工性能，导致负极材料的首效较低；当硅氧材料和锂源的摩尔比过低(即锂源过多)，则得不到理想的负极材料。可选地，所述热处理后的硅氧材料与锂源的摩尔比为(2.5～5):1。
在一些实施方式中，所述混合在混合设备中进行。
作为本申请可选的技术方案，所述保护性气氛包括氮气、氦气、氖气、氩气、氪气和氙气中的至少一种。
可选地，所述烧结的温度为300℃～900℃，具体可以是300℃、400℃、500℃、600℃、700℃、800℃或900℃等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，可选为500℃～800℃。当烧结温度过高，会导致反应剧烈，硅晶粒急剧长大，影响负极材料的循环性能；当烧结温度过低，导致无法生成Li 2Si 2O 5。
可选地，所述烧结的时间为2h～8h，更具体地，可以是2h、3h、4h、5h、6h、7h或8h等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，可以理解地，充分烧结，可以将硅氧化物与锂源充分反应生成Li 2Si 2O 5。
作为本申请可选的技术方案，所述方法还包括：在烧结后，对烧结产品进行后处理，所述后处理包括水洗和酸洗中的至少一种。可以理解地，烧结产物中可能含有Li 2O、Li 4SiO 4、Li 2Si 2O 3等水溶性含锂化合物，而Li 2Si 2O 5不溶于水，通过水洗可以去除烧结产物的杂质相；同样地，通过酸洗也可以去除这些杂质相，从而提高负极材料的首效及循环稳定性。当采用酸洗时，酸溶液例如可以是盐酸、硝酸或硫酸。
作为本申请所述制备方法的进一步可选技术方案，所述方法包括以下步骤：
在保护性气氛或真空下对氧化亚硅进行热处理，热处理温度为700℃～900℃，热处理时间为4h～10h，得到热处理后的氧化亚硅；
在保护性气氛或真空下，按照摩尔比为(2.5～5)：1将所述热处理后的氧化亚硅与锂源混合后，进行烧结，烧结的温度为500℃～800℃，烧结的时间为2h～8h，对烧结产品进行水洗和/或酸洗，得到负极材料。
第三方面，本申请提供一种锂离子电池，所述锂离子电池包含上述第一方面所述的硅氧复合负极材料或上述第二方面所述的制备方法制得的硅氧复合负极材料。
下面分多个实施例对本申请实施例进行进一步的说明。其中，本申请实施例不限定于以下的具体实施例。在保护范围内，可以适当的进行变更实施。
实施例1
本实施例按照如下方法制备负极材料：
(1)取包含3wt％碳包碳层的氧化亚硅500g，在氩气气氛下700℃下热处理4h，得到热处理后的氧化亚硅；
(2)在氩气气氛下，将热处理后的氧化亚硅与金属锂按摩尔比1.5:1在混合设备中混合均匀，得到内部含有锂的硅氧化物；
(3)在氩气气氛下，将内部含有锂的硅氧化物在600℃下烧结6h，并对烧结产品进行酸洗，得到负极材料。
本实施例制备得到的负极材料包括纳米硅、硅氧化物SiO 0.2和晶质的Li 2Si 2O 5，纳米硅均匀分散于SiO 0.2和Li 2Si 2O 5中，纳米硅的平均粒径为6.1nm，Li 2Si 2O 5晶粒的平均粒径为18.3nm，所述负极材料中的Li 2Si 2O 5的质量分数为67wt％。所述负极材料表面形成有碳包覆层。
本实施例制备的负极材料的Li 2Si 2O 5晶粒尺寸测试结果和性能表征结果见表1。
图2为本实施例制备的负极材料的SEM图。
实施例2
本实施例按照如下方法制备负极材料：
(1)取包含3wt％碳包碳层的氧化亚硅500g，在氩气气氛下800℃下热处理4h，得到热处理后的氧化亚硅；
(2)在氩气气氛下，将热处理后的氧化亚硅与金属锂按摩尔比1.5:1在混合设备中混合均匀，得到内部含有锂的硅氧化物；
(3)在氩气气氛下，将内部含有锂的硅氧化物在600℃下烧结6h，并对烧结产品进行酸洗，得到负极材料。
本实施例制备得到的负极材料包括纳米硅、硅氧化物SiO 0.3和晶质的Li 2Si 2O 5，纳米硅均匀分散于SiO 0.3和Li 2Si 2O 5中，纳米硅的平均粒径为7.5nm，Li 2Si 2O 5晶粒的平均粒径为10.4nm，所述负极材料中的Li 2Si 2O 5的质量分数为56wt％。所述负极材料表面形成有碳包覆层。
本实施例制备的负极材料的Li 2Si 2O 5晶粒尺寸测试结果和性能表征结果见表1。
图3为本实施例制备的负极材料的SEM图。
实施例3
本实施例按照如下方法制备负极材料：
(1)取包含10wt％碳包碳层的氧化亚硅300g，在氮气气氛下900℃下热处理10h，得到热处理后的氧化亚硅；
(2)在氮气气氛下，将热处理后的氧化亚硅与碳酸锂按摩尔比4:1在混合设备中混合均匀，得到内部含有锂的硅氧化物；
(3)在氮气气氛下，将内部含有锂的硅氧化物在800℃下烧结8h，并对烧结产品进行酸洗，得到负极材料。
本实施例制备得到的负极材料包括纳米硅、硅氧化物SiO 0.7和晶质的Li 2Si 2O 5，纳米硅均匀分散于SiO 0.7和Li 2Si 2O 5中，纳米硅的平均粒径为3.9nm，Li 2Si 2O 5晶粒的平均粒径为11.6nm，所述负极材料中的Li 2Si 2O 5的质量分数为37wt％。所述负极材料表面形成有碳包覆层。
本实施例制备的负极材料的Li 2Si 2O 5晶粒尺寸测试结果和性能表征结果见表1。
实施例4
本实施例按照如下方法制备负极材料：
(1)取包含2wt％碳包碳层的氧化亚硅800g，在氮气气氛下800℃下热处理4h，得到热处理后的氧化亚硅；
(2)在氮气气氛下，将热处理后的氧化亚硅与醋酸锂按摩尔比7:1在混合设备中混合均匀，得到内部含有锂的硅氧化物；
(3)在氮气气氛下，将内部含有锂的硅氧化物在500℃下烧结8h，并对烧结产品进行水洗，得到负极材料。
本实施例制备得到的负极材料包括纳米硅、硅氧化物SiO 0.8和晶质的Li 2Si 2O 5，纳米硅均匀分散于SiO 0.8和Li 2Si 2O 5中，纳米硅的平均粒径为2.2nm，Li 2Si 2O 5晶粒的平均粒径为10.7nm，所述负极材料中的Li 2Si 2O 5的质量分数为33wt％。所述负极材料表面形成有碳包覆层。
本实施例制备的负极材料的Li 2Si 2O 5晶粒尺寸测试结果和性能表征结果见表1。
实施例5
本实施例按照如下方法制备负极材料：
(1)取包含3wt％碳包碳层的氧化亚硅500g，在氩气气氛下600℃下热处理4h，得到热处理后的氧化亚硅；
(2)在氩气气氛下，将热处理后的氧化亚硅与金属锂按摩尔比1.5:1在混合设备中混合均匀，得到内部含有锂的硅氧化物；
(3)在氩气气氛下，将内部含有锂的硅氧化物在300℃下烧结6h，并对烧 结产品进行酸洗，得到,负极材料。
本实施例制备得到的负极材料包括纳米硅、硅氧化物SiO 0.9和晶质的Li 2Si 2O 5，纳米硅均匀分散于SiO 0.9和Li 2Si 2O 5中，纳米硅的平均粒径为4.6nm，Li 2Si 2O 5晶粒的平均粒径为6.8nm，所述负极材料中的Li 2Si 2O 5的质量分数为30wt％。所述负极材料表面形成有碳包覆层。
本实施例制备的负极材料的Li 2Si 2O 5晶粒尺寸测试结果和性能表征结果见表1。
实施例6
本实施例按照如下方法制备负极材料：
(1)取包含3wt％碳包碳层的SiO 1.5 500g，在氩气气氛下1000℃下热处理4h，得到热处理后的SiO 1.5；
(2)在氩气气氛下，将热处理后的氧化亚硅与金属锂按摩尔比1.5:1在混合设备中混合均匀，得到内部含有锂的硅氧化物；
(3)在氩气气氛下，将内部含有锂的硅氧化物在900℃下烧结6h，并对烧结产品进行酸洗，得到负极材料。
本实施例制备得到的负极材料包括纳米硅、硅氧化物SiO 0.3和晶质的Li 2Si 2O 5，纳米硅均匀分散于SiO 0.3和Li 2Si 2O 5中，纳米硅的平均粒径为12.3nm，Li 2Si 2O 5晶粒的平均粒径为12.2nm，所述负极材料中的Li 2Si 2O 5的质量分数为61wt％。所述负极材料表面形成有碳包覆层。
本实施例制备的负极材料的Li 2Si 2O 5晶粒尺寸测试结果和性能表征结果见表1。
实施例7
本实施例除了步骤(1)热处理温度为570℃之外，其他操作条件和物料均与实施例1相同。
本实施例制备得到的负极材料包括纳米硅、硅氧化物SiO 0.4和晶质的Li 2Si 2O 5，纳米硅均匀分散于SiO 0.4和Li 2Si 2O 5中，纳米硅的平均粒径为8.7nm，Li 2Si 2O 5晶粒的平均粒径为26.5nm，所述负极材料中的Li 2Si 2O 5的质量分数为58wt％。所述负极材料表面形成有碳包覆层。
本实施例制备的负极材料的Li 2Si 2O 5晶粒尺寸测试结果和性能表征结果见表1。
实施例8
本实施例除了步骤(1)热处理温度为1025℃之外，其他操作条件和物料均与实施例1相同。
本实施例制备得到的负极材料包括纳米硅、硅氧化物SiO 0.3和晶质的Li 2Si 2O 5，纳米硅均匀分散于SiO 0.3和Li 2Si 2O 5中，纳米硅的平均粒径为5.4nm，Li 2Si 2O 5晶粒的平均粒径为17.6nm，所述负极材料中的Li 2Si 2O 5的质量分数为 45wt％。所述负极材料还在表面包覆有碳层。
本实施例制备的负极材料的Li 2Si 2O 5晶粒尺寸测试结果和性能表征结果见表1。
对比例1
本实施例按照如下方法制备负极材料：
(1)取包含3wt％碳包碳层的氧化亚硅500g，在氩气气氛下700℃下热处理4h，得到热处理后的氧化亚硅。
本实施例制备得到的负极材料包括热处理的氧化亚硅，不含有纳米硅和Li 2Si 2O 5。
对比例2
本实施例按照如下方法制备负极材料：
(1)取包含3wt％碳包碳层的氧化亚硅500g，在氩气气氛下，将氧化亚硅与金属锂按摩尔比1.5:1在混合设备中混合均匀，得到内部含有锂的硅氧化物；
(2)在氩气气氛下，将内部含有锂的硅氧化物在600℃下烧结6h，并对烧结产品进行酸洗，得到负极材料。
本实施例制备得到的负极材料包括纳米硅、硅氧化物SiO 0.2和晶质的Li 2Si 2O 5，纳米硅均匀分散于SiO 0.2和Li 2Si 2O 5中，纳米硅的平均粒径为6.1nm，Li 2Si 2O 5晶粒的平均粒径为27.4nm，所述负极材料中的Li 2Si 2O 5的质量分数为67wt％。所述负极材料表面形成有碳包覆层。
本对比例制备的负极材料的Li 2Si 2O 5晶粒尺寸测试结果和性能表征结果见表1。
测试方法
Li 2Si 2O 5的晶粒尺寸测试计算方法：
对各实施例和对比例所制备的负极材料粉末进行使用CuKα射线的X射线衍射测定，分析衍射角2θ显示在24.4°～25.0°范围的归属于Li 2Si 2O 5的(111)峰，通过谢乐公式计算Li 2Si 2O 5的晶粒值。
电化学性能测试：
(1)首次效率测试：a、锂离子电池的制备：将制备得到的负极材料：导电炭黑：CMC：SBR＝75:15:5:5的比例涂覆在铜箔上，制备成负极片，金属锂片作为对电极，PP/PE膜作为隔膜，电解液是1mol/L的LiPF 6、碳酸二甲酯和碳酸乙基甲酯混合液(体积比1:1:1)，制成纽扣电池；b、采用蓝电新威5V/10mA型电池测试仪测试电池的电化学性能，电压为1.5V，电流为0.1C，首次效率＝首次充电比容量/首次放电比容量。
(2)循环性能测试：a、锂离子电池的制备：将制备得到的负极材料与石墨按15:85的比例混合得到活性材料，按活性材料：导电炭黑：CMC：SBR＝92:4:2:2的比例涂覆在铜箔上，制备成负极片，金属锂片作为对电极，PP/PE膜作为隔膜， 电解液是1mol/L的LiPF 6、碳酸二甲酯和碳酸乙基甲酯混合液(体积比1:1:1)，制成纽扣电池；b、采用蓝电新威5V/10mA型电池测试仪测试电池的电化学性能，电压为1.5V，电流为0.1C，50周循环保持率＝第50次放电比容量/首次放电比容量。
(3)倍率性能测试：a、锂离子电池的制备：将制备得到的负极材料与石墨按15:85的比例混合得到活性材料，按活性材料：导电炭黑：CMC：SBR＝92:4:2:2的比例涂覆在铜箔上，制备成负极片，金属锂片作为对电极，PP膜作为隔膜，电解液是1mol/L的LiPF 6、碳酸二甲酯和碳酸乙基甲酯混合液(体积比1:1:1)，制成纽扣电池；b、采用蓝电新威5V/10mA型电池测试仪测试电池的电化学性能，电压为1.5V，电流分别为0.1C和3C，3C/0.1C＝3C电流的放电比容量/0.1C电流放电电比容量。
测试结果见下表：
表1
Figure PCTCN2020128783-appb-000001
实施例7的热处理温度过低，导致Li 2Si 2O 5的晶粒过大，使得其循环保持率和容量保持率都较差。
实施例8的热处理温度过高，导致硅氧材料歧化程度不合适，材料的容量和首效均较低。
对比例1没有对氧化亚硅材料进行锂掺杂，导致材料的首效较低。
对比例2没有对氧化亚硅材料进行热处理就直接进行锂掺杂，导致产生的Li 2Si 2O 5晶粒过大，使得其首次库伦效率、循环性能和倍率性能都明显较差。
综合上述实施例和对比例可以看出，实施例1-6的负极材料通过对氧化亚硅材料进行锂掺杂，大幅提高了材料的首次库伦效率，并且通过控制生成的Li 2Si 2O 5晶粒尺寸，使得晶粒的平均粒径小于20nm，最终使材料在获得高的首次库伦效率的同时，提高了材料的循环性能。此外，Li 2Si 2O 5具有良好的锂离子传导特性，结合其较小的晶粒尺寸，更好地保证锂离子顺畅地完成嵌/脱锂反应，表现出良 好的倍率性能。
申请人声明，本申请通过上述实施例来说明本申请的详细工艺设备和工艺流程，但本申请并不局限于上述详细工艺设备和工艺流程，即不意味着本申请必须依赖上述详细工艺设备和工艺流程才能实施。所属技术领域的技术人员应该明了，对本申请的任何改进，对本申请产品各原料的等效替换及辅助成分的添加、具体方式的选择等，均落在本申请的保护范围和公开范围之内。

Claims (12)

  1. 一种负极材料，其特征在于，所述负极材料包括纳米硅、硅氧化物和晶质的Li 2Si 2O 5，其中，Li 2Si 2O 5晶粒的平均粒径小于20nm。
  2. 根据权利要求1所述的负极材料，其特征在于，其满足以下条件a～f的至少一者：
    a.所述硅氧化物的化学式为SiO x，其中，0＜x≤1；
    b.所述硅氧化物和所述Li 2Si 2O 5中分散有所述纳米硅；
    c.所述Li 2Si 2O 5包覆至少部分所述纳米硅和/或所述硅氧化物；
    d.所述纳米硅的粒径为0～15nm且不包含0nm；
    e.所述负极材料中的Li 2Si 2O 5的质量分数为30wt％～70wt％；
    f.所述负极材料的平均粒径为1μm～50μm。
  3. 根据权利要求1～2任一项所述的负极材料，其特征在于，其满足以下条件a～c的至少一者：
    a.所述负极材料表面形成有碳包覆层；
    b.所述负极材料表面形成有碳包覆层，所述碳包覆层的厚度为10nm～2000nm；
    c.所述负极材料表面形成有碳包覆层，所述负极材料中的碳包覆层的质量分数为1wt％～10wt％。
  4. 一种负极材料的制备方法，其特征在于，包括以下步骤：
    在保护性气氛或真空下对硅氧材料进行热处理，得到热处理后的硅氧材料；
    在保护性气氛或真空下将所述热处理后的硅氧材料与锂源混合后，进行烧结，得到负极材料，所述负极材料包括纳米硅、硅氧化物和晶质的Li 2Si 2O 5。
  5. 根据权利要求4所述的制备方法，其特征在于，其满足以下条件a～g的至少一者：
    a.所述Li 2Si 2O 5的平均粒径小于20nm；
    b.所述硅氧化物的化学式为SiO x，其中，0＜x≤1；
    c.所述硅氧化物和所述Li 2Si 2O 5中分散有所述纳米硅；
    d.所述Li 2Si 2O 5包覆至少部分所述纳米硅和/或所述硅氧化物；
    e.所述纳米硅的粒径为0～15nm且不包含0nm；
    f.所述负极材料中的Li 2Si 2O 5的质量分数为30wt％～70wt％；
    g.所述负极材料的平均粒径为1μm～50μm。
  6. 根据权利要求4或5所述的制备方法，其特征在于，其满足以下条件a～g的至少一者：
    a.所述硅氧材料的化学式为SiO y，其中，0＜y＜2；
    b.所述硅氧材料为氧化亚硅；
    c.所述硅氧材料的表面包覆有碳包覆层；
    d.所述硅氧材料的表面包覆有碳包覆层，所述碳包覆层的厚度为10nm～2000nm；
    e.所述保护性气氛包括氮气、氦气、氖气、氩气、氪气和氙气中的至少一种；
    f.所述热处理的温度为600℃～1000℃；
    g.所述热处理的时间为4h～10h。
  7. 根据权利要求4～6任一项所述的制备方法，其特征在于，其满足以下条件a～d的至少一者：
    a.所述锂源包括金属锂、碳酸锂、氢氧化锂和醋酸锂中的至少一种；
    b.所述热处理后的硅氧材料与所述锂源的摩尔比为(1.5～7):1；
    c.所述烧结的温度为300℃～900℃；
    d.所述烧结的时间为2h～8h。
  8. 根据权利要求4～7任一项所述的制备方法，其特征在于，所述方法还包括：在烧结后，对烧结产品进行后处理，所述后处理包括水洗和酸洗中的至少一种。
  9. 根据权利要求4～8任一项所述的制备方法，其特征在于，所述方法还包括：
    对硅氧材料进行碳包覆，所述碳包覆的方式包括气相包碳和固相包碳中的至少一种。
  10. 根据权利要求9所述的制备方法，其特征在于，其满足以下条件a～b的至少一者：
    a.所述碳包覆包括气相包碳，所述气相包碳的条件为：将所述硅氧化物在保护性气氛下升温至600℃～1000℃，通入有机碳源气体，保温0.5h～10h后冷却；其中，所述有机碳源气体包括烃类，所述烃类包括甲烷、乙烯、乙炔和苯中的至少一种；
    b.所述碳包覆包括固相包碳，所述固相包碳的条件为：将所述硅氧化物与碳源融合0.5h～2h后，将得到的碳混合物在600℃～1000℃下碳化2h～6h，冷却；其中，所述碳源包括聚合物、糖类、有机酸和沥青中的至少一种。
  11. 根据权利要求4～10任一项所述的制备方法，其特征在于，包括以下步骤：
    在保护性气氛或真空下对氧化亚硅进行热处理，热处理温度为700℃～900℃，热处理时间为4h～10h，得到热处理后的氧化亚硅；
    在保护性气氛或真空下，按照摩尔比为(2.5～5)：1将所述热处理后的氧化亚硅与锂源混合后，进行烧结，烧结的温度为500℃～800℃，烧结的时间为2h～8h，对烧结产品进行水洗和/或酸洗，得到负极材料。
  12. 一种锂离子电池，其特征在于，所述锂离子电池包含如权利要求1～3任一项所述的负极材料或根据权利要求4～11任一项所述的制备方法制得的负极材料。
PCT/CN2020/128783 2019-11-14 2020-11-13 一种负极材料及其制备方法和锂离子电池 WO2021093865A1 (zh)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US17/615,746 US20220328816A1 (en) 2019-11-14 2020-11-13 Negative electrode material and preparation method therefor, and lithium ion battery
JP2021541129A JP7236547B2 (ja) 2019-11-14 2020-11-13 負極材料、その調製方法及びリチウムイオン電池
EP20886472.8A EP3965194A4 (en) 2019-11-14 2020-11-13 NEGATIVE ELECTRODE MATERIAL AND PRODUCTION METHOD THEREOF AND LITHIUM-ION BATTERY
KR1020217022266A KR20210104114A (ko) 2019-11-14 2020-11-13 음극 재료 및 그 제조 방법과 리튬 이온 전지

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201911112677.3 2019-11-14
CN201911112677.3A CN112803015A (zh) 2019-11-14 2019-11-14 一种负极材料及其制备方法和锂离子电池

Publications (1)

Publication Number Publication Date
WO2021093865A1 true WO2021093865A1 (zh) 2021-05-20

Family

ID=75803670

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/128783 WO2021093865A1 (zh) 2019-11-14 2020-11-13 一种负极材料及其制备方法和锂离子电池

Country Status (6)

Country Link
US (1) US20220328816A1 (zh)
EP (1) EP3965194A4 (zh)
JP (1) JP7236547B2 (zh)
KR (1) KR20210104114A (zh)
CN (1) CN112803015A (zh)
WO (1) WO2021093865A1 (zh)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113948688B (zh) * 2021-09-30 2023-06-09 浙江锂宸新材料科技有限公司 一种改性预锂化硅氧复合材料及其制备方法和应用
CN114005974B (zh) * 2021-12-30 2022-03-22 常州硅源新能材料有限公司 硅氧负极材料、硅氧负极材料的制备方法及锂离子电池
CN114464797B (zh) * 2021-12-31 2024-04-26 长沙矿冶研究院有限责任公司 一种高首效硅氧负极材料及其制备方法
CN114759180A (zh) * 2022-04-28 2022-07-15 中南大学 SiOx/锂硅酸盐复合材料及其制备方法和应用
CN114975967A (zh) * 2022-06-29 2022-08-30 宁波杉杉新材料科技有限公司 一种预锂化硅氧复合材料及其制备方法、负极极片、电池和应用

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103840136A (zh) * 2012-11-21 2014-06-04 信越化学工业株式会社 蓄电器件用负极材料、蓄电器件用电极、蓄电器件、以及它们的制造方法
CN104620427A (zh) * 2012-11-30 2015-05-13 株式会社Lg化学 硅基复合物及其制造方法
CN106816594A (zh) * 2017-03-06 2017-06-09 深圳市贝特瑞新能源材料股份有限公司 一种复合物、其制备方法及在锂离子二次电池中的用途
CN107565115A (zh) * 2017-08-30 2018-01-09 北方奥钛纳米技术有限公司 硅碳负极材料的制备方法、硅碳负极材料以及锂离子电池
CN107851789A (zh) * 2015-08-28 2018-03-27 株式会社大阪钛技术 含 Li 氧化硅粉末及其制造方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6685939B2 (ja) * 2015-01-28 2020-04-22 三洋電機株式会社 非水電解質二次電池用負極活物質及び非水電解質二次電池
WO2018101072A1 (ja) * 2016-11-30 2018-06-07 パナソニックＩｐマネジメント株式会社 負極材料および非水電解質二次電池

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103840136A (zh) * 2012-11-21 2014-06-04 信越化学工业株式会社 蓄电器件用负极材料、蓄电器件用电极、蓄电器件、以及它们的制造方法
CN104620427A (zh) * 2012-11-30 2015-05-13 株式会社Lg化学 硅基复合物及其制造方法
CN107851789A (zh) * 2015-08-28 2018-03-27 株式会社大阪钛技术 含 Li 氧化硅粉末及其制造方法
CN106816594A (zh) * 2017-03-06 2017-06-09 深圳市贝特瑞新能源材料股份有限公司 一种复合物、其制备方法及在锂离子二次电池中的用途
CN107565115A (zh) * 2017-08-30 2018-01-09 北方奥钛纳米技术有限公司 硅碳负极材料的制备方法、硅碳负极材料以及锂离子电池

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3965194A4

Also Published As

Publication number Publication date
JP2022517793A (ja) 2022-03-10
US20220328816A1 (en) 2022-10-13
KR20210104114A (ko) 2021-08-24
EP3965194A1 (en) 2022-03-09
EP3965194A4 (en) 2022-08-10
JP7236547B2 (ja) 2023-03-09
CN112803015A (zh) 2021-05-14

Similar Documents

Publication Publication Date Title
WO2021093865A1 (zh) 一种负极材料及其制备方法和锂离子电池
WO2022001880A1 (zh) 硅氧复合负极材料、负极和锂离子电池及其制备方法
WO2022088543A1 (zh) 用于电池的负极活性材料及其制备方法、电池负极、电池
JP5411781B2 (ja) 非水電解質二次電池用負極材及び非水電解質二次電池用負極材の製造方法並びにリチウムイオン二次電池
WO2021233439A1 (zh) 硅氧复合负极材料及其制备方法和锂离子电池
JP5245592B2 (ja) 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
CN104813522B (zh) 锂二次电池用负极活性物质及其制备方法
CN110556529A (zh) 具有多层核壳结构的负极复合材料及其制备方法和应用
JP7288059B2 (ja) シリコン酸素複合負極材料、その調製方法及びリチウムイオン電池
JP2021506059A (ja) 非水電解質二次電池用負極活物質、及びその製造方法
TWI705606B (zh) 負極活性物質、混合負極活性物質材料、非水電解質二次電池用負極、鋰離子二次電池、負極活性物質的製造方法、以及鋰離子二次電池的製造方法
JP2021504918A (ja) ケイ素酸化物複合体を含む非水電解質二次電池用負極活物質、及びその製造方法
JP2009301935A (ja) 非水電解質二次電池用負極材及びその製造方法、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
CN102958835A (zh) 具有低氧含量的亚微米级的硅粉末
CN111342031B (zh) 一种多元梯度复合高首效锂电池负极材料及其制备方法
JP2010272411A (ja) 非水電解質二次電池用負極材及びその製造方法、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
TWI717479B (zh) 負極活性物質、混合負極活性物質材料、負極活性物質的製造方法
TW201801380A (zh) 負極活性物質、混合負極活性物質材料、非水電解質二次電池用負極、鋰離子二次電池、負極活性物質的製造方法、以及鋰離子二次電池的製造方法
WO2022002057A1 (zh) 硅氧复合负极材料、负极和锂离子电池及其制备方法
JP2023524189A (ja) 複合材料およびその調製方法、負極材料およびリチウムイオン電池
CN114094067A (zh) 三元正极材料、其制备方法及其用途
Qian et al. Effect of rich R-TiO2 on the rate and cycle properties of Li4Ti5O12 as anode for lithium ion batteries
CN116014104A (zh) 富锂镍系正极材料及其制备方法、正极片与二次电池
JP5910479B2 (ja) 非水電解質二次電池用負極活物質、リチウムイオン二次電池及び電気化学キャパシタの製造方法
WO2021136245A1 (zh) 一种用于电池的负极活性材料及其制备方法

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: 20886472

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2021541129

Country of ref document: JP

Kind code of ref document: A

Ref document number: 20217022266

Country of ref document: KR

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 2020886472

Country of ref document: EP

Effective date: 20211202

NENP Non-entry into the national phase

Ref country code: DE