WO2024016446A1 - 一种核壳结构富锂氧化物及制备方法和应用 - Google Patents

一种核壳结构富锂氧化物及制备方法和应用 Download PDF

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WO2024016446A1
WO2024016446A1 PCT/CN2022/118006 CN2022118006W WO2024016446A1 WO 2024016446 A1 WO2024016446 A1 WO 2024016446A1 CN 2022118006 W CN2022118006 W CN 2022118006W WO 2024016446 A1 WO2024016446 A1 WO 2024016446A1
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lithium
rich oxide
core
shell structure
precursor
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French (fr)
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缪建麟
阮丁山
李长东
刘伟健
王雀乐
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广东邦普循环科技有限公司
湖南邦普循环科技有限公司
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—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
    • H01M4/139—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
    • H01M4/36—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
    • 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
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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 invention belongs to the technical field of lithium-ion battery materials, and particularly relates to a core-shell structure lithium-rich oxide and its preparation method and application.
  • the formation process of lithium-ion batteries consumes active lithium due to the formation of a solid electrolyte film (SEI film) on the surface of the negative electrode.
  • SEI film solid electrolyte film
  • a large amount of lithium ions are consumed.
  • the negative electrode needs to be prelithiated to reduce the consumption of active lithium in the cathode material and increase the energy density of the battery.
  • Lithium-rich oxides such as Li 2 NiO 2 , Li 2 CuO 2 , Li 5 FeO 4 , Li 5 AlO 4 , Li 6 CoO 4 , Li 6 MnO 4 , etc. have the characteristics of high charging capacity and low first efficiency, and are uniformly used in cathode materials. Only a small amount of lithium-rich oxide is added during the slurry process to pre-lithiate the negative electrode during battery formation, avoiding the consumption of active lithium in the positive electrode material, thus improving the first Coulombic efficiency of the positive electrode material.
  • lithium-rich oxides due to the high active lithium content in lithium-rich oxides, they easily react with moisture and carbon dioxide in the air to form electrochemically inert lithium compounds, such as LiOH and Li 2 CO 3 , resulting in the failure to achieve the expected lithium supplementation effect during the battery process.
  • lithium-rich oxide has poor conductivity and extremely low ionic and electronic conductivities. Li + is not easy to escape during high-current charging and cannot exert its true capacity. Therefore, the poor conductivity and stability of lithium-rich oxides limit their application in lithium-ion batteries.
  • Carbon coating is the most effective way to improve the stability and conductivity of lithium-rich oxides.
  • the growth of particles during the synthesis process of the material can be inhibited and small-particle materials can be obtained, which greatly shortens the time The escape path of Li + during the charging process, and most carbon materials have good electrical conductivity, which can improve the electrical conductivity of the material.
  • surface coating of materials can provide a good protective barrier to avoid direct contact between the material and moisture and carbon dioxide in the air, thus improving the stability of the material.
  • the present invention aims to solve at least one of the technical problems existing in the prior art.
  • the present invention proposes a core-shell structure lithium-rich oxide and its preparation method and application.
  • the preparation method of the core-shell structure lithium-rich oxide can form uniform and dense carbon coating on the surface of the core-shell structure lithium-rich oxide. coating layer, so that the conductivity of the core-shell structure lithium-rich oxide can reach more than 0.56 S/cm, and the charging capacity decreases within 10% as the current density increases.
  • a method for preparing a core-shell structure lithium-rich oxide including the following steps:
  • the carbon source is at least one of glucose, sucrose, fructose, soluble starch, citric acid, ascorbic acid, carbon nanotubes, graphene oxide, carbon fiber, conductive carbon black or conductive graphite.
  • the surfactant is polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, polypropylene glycol, polyacrylamide, cetyltrimethylammonium bromide, sodium lauryl sulfate, dodecane At least one of sodium dodecyl benzene sulfonate and sodium dodecyl benzene sulfonate.
  • the metal compound is water-insoluble of Ti, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, Ga, Ge, Al, Zr, Nb, Mo, Sn or Sb at least one of the compounds.
  • the mass ratio of the carbon source to the metal compound is 1:(0.2-12).
  • the mass ratio of the carbon source to the metal compound is 1: (0.5-10).
  • the mass ratio of the surfactant to the carbon source is 1:(3-22).
  • the mass ratio of the surfactant to the carbon source is 1:(5-20).
  • the metal compound, carbon source and surfactant account for 8-35wt% of the mass of the mixed solution.
  • the metal compound, carbon source and surfactant account for 10-30wt% of the mass of the mixed solution.
  • the particle size of the sand-ground mixed slurry is less than 120 nm.
  • the particle size of the sand-ground mixed slurry is less than 100 nm.
  • the air inlet temperature during spray drying is 150-300°C
  • the air outlet temperature is 60-150°C
  • the feed rate is 10-120 mL/min.
  • step (2) the air inlet temperature during spray drying is 180-250°C, the air outlet temperature is 80-120°C, and the feed rate is 10-100 mL/min.
  • the heat treatment temperature of the precursor mixture is 200-700°C, and the heat treatment time is 3-15 hours.
  • the temperature of the heat treatment of the precursor mixture is 300-600°C, and the time of heat treatment is 4-12 hours.
  • the inert atmosphere includes at least one of nitrogen or argon, with a purity of ⁇ 99.9%.
  • the lithium source is at least one of anhydrous lithium hydroxide, lithium hydroxide monohydrate and lithium oxide.
  • the temperature of the high-temperature solid-phase reaction is 300-900°C, and the time of the high-temperature solid-phase reaction is 6-50 hours.
  • step (4) the temperature of the high-temperature solid-phase reaction is 400-800°C, and the time of the high-temperature solid-phase reaction is 8-48 hours.
  • step (4) after the high-temperature solid phase reaction, the obtained material is also cooled, crushed and screened.
  • a core-shell structure lithium-rich oxide is prepared by the above preparation method.
  • the core-shell structure lithium-rich oxide includes a lithium-rich oxide matrix and a shell carbon material coating the surface of the lithium-rich oxide matrix.
  • the chemical formula of the lithium-rich oxide matrix is Li x Me a M b O y
  • the Me is Ti, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, Ga, Ge, Al, At least one of Zr, Nb, Mo, Sn and Sb
  • the Me is at least one of Ni, Co, Mn, Fe, Cu and Al.
  • the thickness of the shell carbon material is 0.5-25% of the lithium-rich oxide matrix.
  • the thickness of the shell carbon material is 1-20% of the lithium-rich oxide matrix.
  • the preparation method of the core-shell structure lithium-rich oxide of the present invention combines liquid phase sanding and spray drying to prepare a carbon material composite nano-precursor, and then the precursor is lithiated and sintered to obtain a carbon coating with a core-shell structure.
  • Liquid-phase sanding can grind metal compounds into nanoparticles with small particle sizes, and can evenly disperse the carbon source medium on the surface of each metal compound particle.
  • the solvent can be dried quickly through spray drying, and the carbon source is evenly coated on the surface of the metal compound particles or distributed between the metal compound particles to obtain a uniform mixture.
  • the mixture is then heat-treated in an inert atmosphere to decompose the carbon source in the precursor to obtain a carbon material, and to decompose the metal compound to obtain a composite precursor of the carbon material and the metal oxide.
  • the carbon material in the precursor can inhibit the agglomeration and growth of particles and form a uniform and dense carbon coating layer to obtain a lithium-rich oxide with a core-shell structure.
  • the carbon material in the shell structure acts as a conductive network to improve the overall conductivity of the material, and the dense carbon coating layer can serve as a protective layer for the core material, avoiding direct contact between the core material and the air, thus improving the stability of the material.
  • the present invention first prepares a carbon composite precursor of nanoparticles, and then obtains a lithium-rich oxide with a core-shell structure through lithiation and sintering.
  • the carbon material can effectively inhibit the growth of grains during the sintering process and can also be coated in the lithium-rich oxide. surface, improving the overall stability and conductivity of lithium-rich oxide.
  • the prepared lithium-rich oxide has small particles, high capacity, good conductivity and stability, a simple preparation process, uniform coating and controllable coating layer thickness.
  • the mixture of carbon source and metal compound adopts liquid phase sand grinding method.
  • the metal compound can achieve a uniform crushing effect through high-speed grinding, resulting in small particles and good distribution. Uniform nanoparticles, and the liquid phase mixture can evenly distribute the carbon source on the surface of the metal compound particles to obtain a uniform mixed solution.
  • spray drying is used to dehydrate the precursor slurry before heat treatment. Compared with direct heat treatment of the slurry, spray drying can achieve rapid dehydration of the slurry and evenly distribute the carbon source on the surface of the metal compound particles. The dried mixture is then subjected to high-temperature heat treatment to obtain a dense and uniform carbon coating precursor;
  • the precursor mixture provided has smaller particles after liquid phase grinding, and the composite carbon material can further inhibit the agglomeration and growth of particles during the lithiation and sintering process of the precursor. , which is beneficial to the preparation of lithium-rich oxides with small particles and uniform distribution;
  • the carbon material of the shell layer is coated on the surface of the lithium-rich oxide, which can improve the overall conductivity of the material; the shell layer The carbon material can avoid direct contact between the main material and the air, slow down the reaction with water and carbon dioxide in the air, and improve the stability of the material in the air.
  • Figure 1 is an SEM image of the lithium-rich oxide of Example 1 and Comparative Example 1;
  • Figure 2 is a TEM image of the lithium-rich oxide of Example 1;
  • Figure 3 is the first charging curve of 0.2C current density of Example 1 and Comparative Example 1.
  • a method for preparing a core-shell structure lithium-rich oxide including the following steps:
  • a core-shell structure lithium-rich oxide is prepared by the above-mentioned preparation method.
  • the shell carbon material of the core-shell structure lithium-rich oxide is 10wt% of the mass of the lithium-rich oxide.
  • the lithium-rich oxide precursor is carbon
  • the composite of material and nano-Fe 3 O 4 is prepared by liquid-phase sanding, spray drying and high-temperature carbonization of metal compounds and carbon sources, in which the carbon material is evenly coated on the surface of Fe 3 O 4 particles.
  • a method for preparing a core-shell structure lithium-rich oxide including the following steps:
  • a core-shell structure lithium-rich oxide is prepared by the above-mentioned preparation method.
  • the shell carbon material in the core-shell structure lithium-rich oxide is 10wt% of the mass of Li 5 Fe 0.5 Al 0.5 O 4 , and its precursor is carbon
  • the composite of the material with Fe 2 O 3 and Al 2 O 3 is prepared by liquid-phase sanding of the metal compound and carbon source, spray drying, and high-temperature carbonization. The carbon material is evenly coated in Fe 2 O 3 and Al 2 O between 3 particles.
  • a method for preparing a core-shell structure lithium-rich oxide including the following steps:
  • a core-shell structure lithium-rich oxide is prepared by the above-mentioned preparation method.
  • the shell carbon material of the core-shell structure lithium-rich oxide is 5wt% of the mass of the lithium-rich oxide.
  • the lithium-rich oxide precursor is carbon
  • the composite of material and nano-CoO and MnO is prepared by liquid-phase sanding, spray drying and high-temperature carbonization of metal compounds and carbon sources, in which the carbon material is evenly dispersed between CoO and MnO particles.
  • a method for preparing a core-shell structure lithium-rich oxide including the following steps:
  • a core-shell structure lithium-rich oxide is prepared by the above-mentioned preparation method.
  • the shell carbon material in the core-shell structure lithium-rich oxide is 2wt% of the mass of Li 2 Ni 0.7 Cu 0.3 O 2 , and its precursor is carbon
  • the composite of the material with CuO and NiO is prepared by liquid-phase sanding, spray drying and high-temperature carbonization of the metal compound and carbon source. The carbon material is evenly coated on the surface of CuO and NiO.
  • a method for preparing lithium-rich oxide including the following steps:
  • a lithium-rich oxide is prepared by the above-mentioned preparation method, wherein the lithium-rich oxide is not carbon-coated.
  • the precursor of the lithium-rich oxide is nanometer Fe 3 O 4 by liquid-phase sanding of the metal compound. Prepared by spray drying and high temperature treatment.
  • Comparative Example 2 (Compared with Example 1, the timing of adding the carbon source is different, and the carbon source is added during heat treatment under an inert atmosphere)
  • a method for preparing lithium-rich oxide including the following steps:
  • a lithium-rich oxide is prepared by the above preparation method, wherein the carbon content in the lithium-rich oxide is 10%.
  • the lithium-rich oxide precursor is obtained by liquid-phase sand grinding and spray drying of Fe 3 O 4 Nano-Fe 3 O 4 is then dry-mixed with carbon source and prepared by high-temperature carbonization.
  • Comparative Example 3 (Compared with Example 1, the mixed slurry was first heat treated in an inert atmosphere and then spray dried)
  • a method for preparing lithium-rich oxide including the following steps:
  • a lithium-rich oxide is prepared by the above preparation method, wherein the carbon content in the lithium-rich oxide is 10%.
  • the lithium-rich oxide precursor is liquid-phase sanded through nanometer Fe 3 O 4 and a carbon source. Obtained by high temperature carbonization.
  • the core-shell structure lithium-rich oxide prepared in Examples 1-4 and the lithium-rich oxide prepared in Comparative Examples 1-3 were mixed with conductive carbon black and PVDF according to a mass ratio of 8:1:1.
  • NMP was used as Solvent, stir quickly for 30 minutes, and adjust to a slurry. The slurry is then coated on aluminum foil and dried. After drying, the positive electrode sheet is obtained by rolling and cutting. Use the positive electrode sheet and the metal lithium sheet as the positive and negative electrodes respectively, assemble them into button batteries, and conduct charge and discharge tests on the batteries.
  • the test voltage range is 3.0 ⁇ 4.25V, and the current density is 0.01C, 0.05C, 0.1C, respectively. Charge and discharge tests were performed at 0.2C.
  • Table 1 The test results are shown in Table 1.
  • the conductivity of the core-shell structure lithium-rich oxide prepared by the preparation method of the present invention can reach more than 0.56S/cm.
  • the lithium-rich oxide of Comparative Example 1 is not carbon-coated.
  • the conductivity is almost 0, almost an insulator, and the capacity decreases significantly as the current density increases; while the charging capacity of the carbon-coated lithium-rich oxides in Examples 1-4 decreases slightly as the current density increases.
  • the carbon-coated precursor is first prepared by spray drying.
  • the carbon source can be well coated on the surface of the metal oxide by flash evaporation, and then the precursor is sintered with lithium to obtain the core shell. Structure of lithium-rich oxides.
  • Figure 1 is an SEM image of the lithium-rich oxide of Example 1 and Comparative Example 1. It can be seen that the core-shell structure lithium-rich oxide prepared in Example 1 has small particle size, uniform step-by-step, and less particle agglomeration; while the lithium-rich oxide prepared in Comparative Example 1 has a small particle size. The lithium-rich oxide particles are large and the particles are obviously agglomerated, indicating that the carbon-coated precursor can effectively suppress the growth of lithium-rich oxide particles during the sintering process and maintain good dispersion of the particles.
  • FIG. 2 is a TEM image of a lithium-rich oxide with a core-shell structure in Example 1. It can be seen that a lithium-rich oxide with a core-shell structure can be prepared using the preparation method provided by the present invention. The carbon shell is evenly coated on the lithium-rich oxide particles. surface.
  • Figure 3 is the first charging curve of 0.2C current density of Example 1 and Comparative Example 1.
  • the core-shell structure lithium-rich oxide prepared in Example 1 has high charging capacity, low voltage platform and small polarization; while the core-shell structure lithium-rich oxide prepared in Comparative Example 1
  • the lithium-rich oxide has extremely low capacity, high charging platform, and large polarization; it shows that the carbon-coated lithium-rich oxide has better ion conductivity and still maintains a high charging capacity under high current.

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Abstract

本发明公开了一种核壳结构富锂氧化物的制备方法和应用，其中制备方法包括以下步骤：(1)将金属化合物、碳源与表面活性剂的水溶液混合，砂磨得到纳米级的混合浆料；(2)将所述纳米级的混合浆料进行喷雾干燥，得到干燥的前驱体混料；(3)将所述前驱体混料在惰性气氛下进行热处理，冷却后得到碳材料包覆金属氧化物的复合前驱体；(4)将所述碳材料包覆金属氧化物的复合前驱体与锂源混合后，在惰性气氛下进行高温固相反应，得到所述核壳结构富锂氧化物。该核壳结构富锂氧化物的制备方法能在核壳结构富锂氧化物表面形成包覆均匀且致密的碳包覆层。

Description

一种核壳结构富锂氧化物及制备方法和应用 技术领域
本发明属于锂离子电池材料技术领域，特别涉及一种核壳结构富锂氧化物及制备方法和应用。
背景技术
锂离子电池的化成过程因负极表面形成固体电解质膜(SEI膜)需消耗活性锂，尤其对于锡基和硅基负极等高容量负极，需要消耗大量的锂离子。为避免此过程消耗正极材料中活性锂，需对负极进行预锂化来降低正极材料中活性锂的消耗，以提高电池的能量密度。
富锂氧化物如Li 2NiO 2、Li 2CuO 2、Li 5FeO 4、Li 5AlO 4、Li 6CoO 4、Li 6MnO 4等因具有高充电容量低首效的特点，在正极材料匀浆过程中仅需加入少量的富锂氧化物，即可在电池化成中对负极进行预锂化，避免消耗正极材料中的活性锂，从而提高正极材料的首次库伦效率。但由于富锂氧化物中活性锂含量高，在空气中极易与水分和二氧化碳反应生成电化学惰性的锂化合物，如LiOH和Li 2CO 3，导致在电池过程无法发挥预期的补锂效果。且富锂氧化物的导电性差，离子和电子电导率极低，在大电流充电过程中Li +不易脱出，无法发挥其真实的容量。因此，富锂氧化物的导电性和和稳定性差的问题限制了其在锂离子电池中的应用。
碳包覆是改善富锂氧化物稳定性和导电性最有效的途径，通过对富锂氧化物进行碳包覆，可以抑制材料在合成过程中颗粒的生长，得到小颗粒的材料，这大幅缩短充电过程Li +的脱出路径，并且大部分碳材料均有较好的导电性，可以提高材料的电导率。此外，对材料进行表面包覆，可以提供良好的保护屏障，避免材料与空气中的水分和二氧化碳直接接触，从而提高材料的稳定性。
但在实际操作中，现有的工艺对富锂氧化物进行碳包覆时，极易导致碳包覆不均匀，且包覆层十分松散，导致制备得到的碳包覆的富锂氧化物的电导率较差且充电容量随着电流密度提高会显著下降。因此，如何在富锂氧化物表面包覆均匀且致密的包覆层成为当前研究的热点。
发明内容
本发明旨在至少解决现有技术中存在的技术问题之一。为此，本发明提出一种核壳结构富锂氧化物及制备方法和应用，该核壳结构富锂氧化物的制备方法能在核壳结构富锂氧化物表面形成包覆均匀且致密的碳包覆层，从而使得该核壳结构富锂氧化物的电导率能达到0.56 S/cm以上，且充电容量随着电流密度提高降低幅度在10％以内。
本发明的上述技术目的是通过以下技术方案得以实现的：
一种核壳结构富锂氧化物的制备方法，包括以下步骤：
(1)将金属化合物、碳源与表面活性剂的水溶液混合，砂磨得到纳米级的混合浆料；
(2)将所述纳米级的混合浆料进行喷雾干燥，得到干燥的前驱体混料；
(3)将所述前驱体混料在惰性气氛下进行热处理，冷却后得到碳材料包覆金属氧化物的复合前驱体；
(4)将所述碳材料包覆金属氧化物的复合前驱体与锂源混合后，在惰性气氛下进行高温固相反应，得到所述核壳结构富锂氧化物。
优选的，所述碳源为葡萄糖、蔗糖、果糖、可溶性淀粉、柠檬酸、抗坏血酸、碳纳米管、氧化石墨烯、碳纤维、导电炭黑或导电石墨中的至少一种。
优选的，所述表面活性剂为聚乙二醇、聚乙烯醇、聚乙烯吡咯烷酮、聚丙二醇、聚丙烯酰胺、十六烷基三甲基溴化铵、十二烷基硫酸钠、十二烷基磺酸钠、十二烷基苯磺酸钠中的至少一种。
优选的，步骤(1)中，所述金属化合物为Ti、V、Cr、Mn、Fe、Ni、Co、Cu、Zn、Ga、Ge、Al、Zr、Nb、Mo、Sn或Sb的水不溶性化合物中的至少一种。
优选的，步骤(1)中，所述碳源与所述金属化合物的质量比为1:(0.2-12)。
进一步优选的，步骤(1)中，所述碳源与所述金属化合物的质量比为1:(0.5-10)。
优选的，步骤(1)中，所述表面活性剂与所述碳源的质量比为1:(3-22)。
进一步优选的，步骤(1)中，所述表面活性剂与所述碳源的质量比为1:(5-20)。
优选的，步骤(1)中，所述金属化合物、碳源与表面活性剂占所述混合溶液质量的8-35wt％。
进一步优选的，步骤(1)中，所述金属化合物、碳源与表面活性剂占所述混合溶液质量的10-30wt％。
优选的，步骤(1)中，经过砂磨后的混合浆料的粒径小于120nm。
进一步优选的，步骤(1)中，经过砂磨后的混合浆料的粒径小于100nm。
优选的，步骤(2)中，所述喷雾干燥时的进风口温度为150-300℃，出风口温度为60-150℃，进料速率为10-120mL/min。
进一步优选的，步骤(2)中，所述喷雾干燥时的进风口温度为180-250℃，出风口温度为80-120℃，进料速率为10-100mL/min。
优选的，步骤(3)中，所述前驱体混料的热处理的温度为200-700℃，热处理的时间为3-15h。
进一步优选的，步骤(3)中，所述前驱体混料的热处理的温度为300-600℃，热处理的时间为4-12h。
优选的，所述惰性气氛包括氮气或氩气中的至少一种，纯度≥99.9％。
优选的，步骤(4)中，所述锂源为无水氢氧化锂、单水氢氧化锂及氧化锂中的至少一种。
优选的，步骤(4)中，所述高温固相反应的温度为300-900℃，高温固相反应的时间为6-50h。
进一步优选的，步骤(4)中，所述高温固相反应的温度为400-800℃，高温固相反应的时间为8-48h。
优选的，步骤(4)中，高温固相反应后还对得到的物料进行了冷却、粉碎及过筛处理。
一种核壳结构富锂氧化物，由如上所述的制备方法制备得到。
优选的，所述核壳结构富锂氧化物包括富锂氧化物基体以及包覆在所述富锂氧化物基体表面的壳层碳材料。
优选的，所述富锂氧化物基体的化学式为Li xMe aM bO y，所述Me为Ti、V、Cr、Mn、Fe、Ni、Co、Cu、Zn、Ga、Ge、Al、Zr、Nb、Mo、Sn和Sb中的至少一种；所述M为Ti、V、Cr、Mn、Fe、Ni、Co、Cu、Zn、Ga、Ge、Al、Zr、Nb、Mo、Sn和Sb中的至少一种；其中，2≤x≤6，2≤y≤4，0.5≤a≤1，0≤b≤0.5，a+b＝1。
优选的，所述Me和M的平均价态为z，其中z＝2y-x。
优选的，所述Me为Ni、Co、Mn、Fe、Cu和Al中的至少一种。
优选的，所述壳层碳材料的厚度为富锂氧化物基体的0.5-25％。
进一步优选的，所述壳层碳材料的厚度为富锂氧化物基体的1-20％。
如上所述的核壳结构富锂氧化物在锂离子电池中的应用。
本发明核壳结构富锂氧化物的制备方法结合液相砂磨和喷雾干燥制备得到碳材料复合的纳米前驱体，再将该前驱体进行锂化烧结即可得到具有核壳结构的碳包覆的富锂氧化物。液相砂磨可使金属化合物磨成粒度小的纳米颗粒，且可使碳源介质均匀分散在每个金属化合物颗粒表面。通过喷雾干燥可以使溶剂快速干燥，碳源均匀地包覆在金属化合物颗粒表面或分布在金属化合物颗粒之间，得到均匀的混合物。再将混合物在惰性气氛下进行热处理，使前驱体中的碳源分解得到碳材料，并且使金属化合物分解，得到碳材料与金属氧化物的复合 前驱体。在前驱体锂化烧结过程中，前驱体中的碳材料可以抑制颗粒间的团聚长大，并且形成均匀致密的碳包覆层，得到核壳结构的富锂氧化物。壳结构中的碳材料作为导电网络可以提高材料整体的导电性，并且致密的碳包覆层可作为核材料的保护层，避免了核材料与空气直接接触，从而提高材料的稳定性。
本发明先制备纳米颗粒的碳复合前驱体，再通过锂化烧结得到核壳结构的富锂氧化物，其中碳材料即可有效抑制烧结过程晶粒长大，亦可包覆在富锂氧化物表面，改善富锂氧化物整体的稳定性和导电性。制备得到的富锂氧化物颗粒小、容量高、导电性和稳定性好，制备工艺简单，包覆均匀且包覆层厚度可控。
本发明的有益效果是：
(1)本发明核壳结构富锂氧化物的制备方法中，碳源与金属化合物的混料采用液相砂磨的方法，金属化合物通过高速研磨可达到均匀的破碎效果，得到颗粒小、分布均匀的纳米颗粒，且液相混料可使碳源均匀分布在金属化合物颗粒表面，得到均匀的混合溶液。此外，对前驱体浆料进行热处理前先采用喷雾干燥的方法进行脱水，相较于对浆料直接进行热处理，喷雾干燥可实现浆料快速脱水，并且使碳源均匀分布在金属化合物颗粒表面，再将干燥的混料通过高温热处理得到致密且均匀的碳包覆前驱体；
(2)本发明核壳结构富锂氧化物的制备方法中，提供的前驱体混料经液相研磨颗粒较小，其中复合的碳材料在前驱体锂化烧结过程可以进一步抑制颗粒团聚长大，有利于制备颗粒小、分布均匀的富锂氧化物；
(3)本发明核壳结构富锂氧化物的制备方法制备得到的核壳结构富锂氧化物，壳层的碳材料包覆在富锂氧化物表面，可以提高材料整体的导电性；壳层的碳材料可以避免主体材料与空气直接接触，减缓与空气中水和二氧化碳的反应，提高材料在空气中的稳定性。
附图说明
图1为实施例1和对比例1的富锂氧化物的SEM图；
图2为实施例1的富锂氧化物的TEM图；
图3为实施例1和对比例1的0.2C电流密度首次充电曲线。
具体实施方式
下面结合具体实施例对本发明做进一步的说明。
实施例1：
一种核壳结构富锂氧化物的制备方法，包括以下步骤：
(1)将1kg Fe 3O 4、1.5kg葡萄糖和50g聚乙二醇加入到25L去离子水中，充分搅拌后 进行砂磨，在转速1500rpm/min下研磨30min，得到混合浆料。
(2)将混合浆料进行喷雾干燥，控制进料速率100mL/min，进风口温度220℃，出风口温度110℃，浆料干燥后得到前驱体混料；
(3)将前驱体混料在氮气气氛下进行热处理，升温至600℃保温4h，冷却后得到碳材料与Fe 3O 4复合前驱体；
(4)将复合前驱体与氢氧化锂按摩尔比Li/Fe＝6.0的比例进行混合，混料在纯度99.99％氮气气氛下加热至650℃保温12h，冷却后进行破碎、过筛，得到核壳结构的富锂氧化物Li 5FeO 4。
一种核壳结构富锂氧化物，由上述的制备方法制备得到，该核壳结构富锂氧化物中壳层碳材料为富锂氧化物质量的10wt％，该富锂氧化物前驱体为碳材料与纳米Fe 3O 4的复合物，通过将金属化合物和碳源进行液相砂磨，喷雾干燥、高温碳化制备得到，其中碳材料均匀包覆在Fe 3O 4颗粒表面。
实施例2：
一种核壳结构富锂氧化物的制备方法，包括以下步骤：
(1)将570g Fe 2O 3、364g Al 2O 3、1.5kg葡萄糖和50g聚乙二醇加入到25L去离子水中，充分搅拌后将溶液进行砂磨，在转速1500rpm/min下研磨30min，得到混合浆料。
(2)将混合浆料进行喷雾干燥，控制进料速率100mL/min，进风口温度220℃，出风口温度110℃，浆料干燥后得到前驱体混料；
(3)将前驱体混料在氮气气氛下进行热处理，升温至600℃保温4h，冷却后得到碳材料与Fe 3O 4复合前驱体；
(4)将复合前驱体与单水氢氧化锂按摩尔比Li/(Fe+Al)＝6.5的比例进行混合，混料在纯度99.99％氮气气氛下加热至650℃保温12h，冷却后进行破碎、过筛，得到核壳结构的富锂氧化物Li 5Fe 0.5Al 0.5O 4。
一种核壳结构富锂氧化物，由上述的制备方法制备得到，该核壳结构富锂氧化物中壳层碳材料为Li 5Fe 0.5Al 0.5O 4质量的10wt％，其前驱体为碳材料与Fe 2O 3和Al 2O 3的复合物，通过将金属化合物和碳源进行液相砂磨，喷雾干燥、高温碳化制备得到，碳材料均匀包覆在Fe 2O 3和Al 2O 3颗粒之间。
实施例3：
一种核壳结构富锂氧化物的制备方法，包括以下步骤：
(1)将800g Co(OH) 2、247g MnCO 3、88g氧化石墨烯和40g聚乙烯醇加入到15L去离 子水中，充分搅拌后将溶液进行砂磨，在转速1800rpm/min下研磨20min，得到混合浆料。
(2)将混合浆料进行喷雾干燥，控制进料速率80mL/min，进风口温度180℃，出风口温度100℃，浆料干燥后得到前驱体混料；
(3)将前驱体混料在氮气气氛下进行热处理，升温至500℃保温8h，冷却后得到石墨烯与CoO、MnO复合前驱体；
(4)将复合前驱体与氧化锂按摩尔比Li/(Co+Mn)＝7.0的比例进行混合，混料在纯度99.999％氮气气氛下加热至500℃保温18h，冷却后进行破碎、过筛，得到核壳结构的富锂氧化物Li 6Co 0.8Mn 0.2O 4。
一种核壳结构富锂氧化物，由上述的制备方法制备得到，该核壳结构富锂氧化物中壳层碳材料为富锂氧化物质量的5wt％，该富锂氧化物前驱体为碳材料与纳米CoO和MnO的复合物，通过将金属化合物和碳源进行液相砂磨，喷雾干燥、高温碳化制备得到，其中碳材料均匀分散在CoO和MnO颗粒之间。
实施例4：
一种核壳结构富锂氧化物的制备方法，包括以下步骤：
(1)将408g Ni(OH) 2、184g Cu(OH) 2、100g葡萄糖和20g聚乙烯吡咯烷酮加入到10L去离子水中，充分搅拌后将溶液进行砂磨，在转速1500rpm/min下研磨40min，得到混合浆料。
(2)将混合浆料进行喷雾干燥，控制进料速率120mL/min，进风口温度200℃，出风口温度105℃，浆料干燥后得到前驱体混料；
(3)将前驱体混料在氮气气氛下进行热处理，升温至400℃保温8h，冷却后得到碳材料与NiO、CuO复合前驱体；
(4)将复合前驱体与碳酸锂按摩尔比Li/(Ni+Cu)＝2.5的比例进行混合，混料在纯度99.9％氮气气氛下加热至550℃保温8h，冷却后进行破碎、过筛，得到核壳结构的富锂氧化物Li 2Ni 0.7Cu 0.3O 2。
一种核壳结构富锂氧化物，由上述的制备方法制备得到，该核壳结构富锂氧化物中壳层碳材料为Li 2Ni 0.7Cu 0.3O 2质量的2wt％，其前驱体为碳材料与CuO和NiO的复合物，通过将金属化合物和碳源进行液相砂磨，喷雾干燥、高温碳化制备得到，碳材料均匀包覆在CuO和NiO表面。
对比例1：(与实施例1相比未加入碳源进行碳包覆)
一种富锂氧化物的制备方法，包括以下步骤：
(1)将1kg Fe 3O 4和50g聚乙二醇加入到25L去离子水中，充分搅拌后进行砂磨，在转速1500rpm/min下研磨30min，得到混合浆料。
(2)将混合浆料进行喷雾干燥，控制进料速率100mL/min，进风口温度220℃，出风口温度110℃，浆料干燥后得到前驱体混料；
(3)将前驱体混料在氮气气氛下进行热处理，升温至600℃保温4h，冷却后得到Fe 3O 4前驱体；
(4)将Fe 3O 4前驱体与氢氧化锂按摩尔比Li/Fe＝6.0的比例进行混合，混料在纯度99.99％氮气气氛下加热至650℃保温12h，冷却后进行破碎、过筛，得到富锂氧化物Li 5FeO 4。
一种富锂氧化物，由上述的制备方法制备得到，其中富锂氧化物未进行碳包覆，该富锂氧化物前驱体为纳米Fe 3O 4，通过将金属化合物进行液相砂磨、喷雾干燥、高温处理制备得到。
对比例2：(与实施例1相比，加入碳源的时机不同，在惰性气氛下进行热处理时加入碳源)
一种富锂氧化物的制备方法，包括以下步骤：
(1)将1kg Fe 3O 4和50g聚乙二醇加入到25L去离子水中，充分搅拌后进行砂磨，在转速1500rpm/min下研磨30min，得到混合浆料。
(2)将混合浆料进行喷雾干燥，控制进料速率100mL/min，进风口温度220℃，出风口温度110℃，浆料干燥后得到前驱体混料；
(3)将前驱体混料与1.5kg葡萄糖进行干法球磨混合，混料在氮气气氛下进行热处理，升温至600℃保温4h，冷却后得到Fe 3O 4复合前驱体；
(4)将Fe 3O 4复合前驱体与氢氧化锂按摩尔比Li/Fe＝6.0的比例进行混合，混料在纯度99.99％氮气气氛下加热至650℃保温12h，冷却后进行破碎、过筛，得到富锂氧化物Li 5FeO 4。
一种富锂氧化物，由上述的制备方法制备得到，其中富锂氧化物中的碳含量为10％，该富锂氧化物前驱体通过将Fe 3O 4进行液相砂磨、喷雾干燥得到纳米Fe 3O 4，再与碳源进行干混，高温碳化制备得到。
对比例3：(与实施例1相比，将混合浆料先在惰性气氛下进行热处理后，再进行喷雾干燥)
一种富锂氧化物的制备方法，包括以下步骤：
(1)将1kg Fe 3O 4、1.5kg葡萄糖和50g聚乙二醇加入到25L去离子水中，充分搅拌后进行砂磨，在转速1500rpm/min下研磨30min，得到混合浆料；
(2)将混合浆料在氮气气氛下升温至600℃保温4h，冷却后得到碳材料与Fe 3O 4复合前驱体；
(3)将Fe 3O 4复合前驱体与氢氧化锂按摩尔比Li/Fe＝6.0加入到去离子水中进行湿法混合，水料质量比3:1，再将混合浆料进行喷雾干燥，控制进料速率100mL/min，进风口温度220℃，出风口温度110℃，浆料干燥后得到前驱体与氢氧化锂的混料；
(4)将混料在纯度99.99％氮气气氛下加热至650℃保温12h，冷却后进行破碎、过筛，得到富锂氧化物Li 5FeO 4。
一种富锂氧化物，由上述的制备方法制备得到，其中富锂氧化物中的碳含量为10％，该富锂氧化物前驱体通过纳米Fe 3O 4与碳源进行液相砂磨、高温碳化得到。
测试例：
分别将实施例1-4制备的核壳结构富锂氧化物和对比例1-3制备的富锂氧化物与导电炭黑、PVDF按照质量比8:1:1的配比进行混合，NMP作为溶剂，快速搅拌30min，调至浆状料。然后将浆料涂覆于铝箔上进行烘干，干燥后辊压、裁片得到正极片。分别将此正极片和金属锂片作为正负极，组装成扣式电池，并将电池进行充放电测试，测试电压范围为3.0～4.25V，分别在电流密度0.01C，0.05C，0.1C，0.2C下进行充放电测试，测试结果见表1。
取相同质量的实施例1-4制备的核壳结构富锂氧化物和对比例1-3制备的富锂氧化物，在20％湿度环境下将样品平铺在托盘上，每隔12h、24h、48h进行取样，测试样品中Li 2CO 3及LiOH的含量，并按照上述的制备方法制备成扣式电池后在电流密度为0.01C下进行充放电测试，测试结果见表2。
表1：充放电测试结果
Figure PCTCN2022118006-appb-000001
由表1可知，本发明制备方法制备得到的核壳结构富锂氧化物的电导率能达到0.56S/cm 以上，相比实施例1，对比例1的富锂氧化物没有进行碳包覆，电导率几乎为0，几乎为绝缘体，容量随着电流密度增大大幅降低；而实施例1-4进行碳包覆的富锂氧化物充电容量随着电流密度提高降低幅度小，当电流密度从0.01C升至0.2C时，充电容量的降低幅度在10％以内，电导率高，其中电导率随碳包覆量的提高的增大；实施例1，对比例2和对比例3虽然都进行了碳包覆，但电导率没有明显改善，大电流下充电容量低，原因是对比例2为碳源与金属氧化物的复合方式为简单的干法混合，得到的前驱体与碳材料的复合效果差，在烧结过程并未包覆在富锂氧化物表面，而对比例3虽通过液相法将金属氧化物和碳源进行混合，但前驱体是直接将浆料进行热处理制备得到，由于缓慢的热处理会导致碳源与金属氧化物发生偏析，不能有效包覆在金属氧化物表面，用此前驱体与锂源通过液相混合，再进行喷雾干燥导致更难包覆均匀；而本申请实施例1-4是先通过喷雾干燥制备得到碳包覆的前驱体，通过闪蒸的方式可以使碳源较好地包覆在金属氧化物表面，再将前驱体配锂烧结可以得到核壳结构的富锂氧化物。
表2：20％湿度环境下测试结果
Figure PCTCN2022118006-appb-000002
由表2可知，随着放置时间的延长，实施例1和对比例1的富锂氧化物中的碳酸锂和氢氧化锂的含量都呈递增趋势，不同的是实施例1增长幅度较小，容量略微降低，对比例1则出现明显变化，碳酸锂和氢氧化锂含量骤增，容量骤减，表明富锂氧化物的稳定性极差，在湿度较低的环境下快速变质，而本方面制备方法制备得到的核壳结构富锂氧化物稳定性优良，表明碳包覆可以有效抑制主体材料与空气中的H 2O和CO 2反应。
成品质量：
图1为实施例1和对比例1富锂氧化物的SEM图，可以看到实施例1制备的核壳结构富锂氧化物粒度小，分步均匀，颗粒团聚少；而对比例1制备的富锂氧化物颗粒大，颗粒明显团聚，表明碳包覆的前驱体在烧结过程中可以有效抑富锂氧化物制颗粒长大，使颗粒保持 良好的分散性。
图2为实施例1核壳结构富锂氧化物的TEM图，可以看到用本发明提供的制备方法可以制备得到核壳结构的富锂氧化物，碳壳均匀包覆在富锂氧化物颗粒表面。
图3为实施例1和对比例1的0.2C电流密度首次充电曲线，实施例1所制备的核壳结构富锂氧化物充电容量高，且电压平台低，极化小；而对比例1制备的富锂氧化物容量极低，且充电平台高，极化大；表明进行碳包覆的富锂氧化物离子电导率较好，在大电流下仍保持着较高的充电容量。
上述实施例为本发明较佳的实施方式，但本发明的实施方式并不受上述实施例的限制，其他的任何未背离本发明的精神实质与原理下所作的改变、修饰、替代、组合、简化，均应为等效的置换方式，都包含在本发明的保护范围之内。

Claims (10)

  1. 一种核壳结构富锂氧化物的制备方法，其特征在于：包括以下步骤：
    (1)将金属化合物、碳源与表面活性剂的水溶液混合，砂磨得到纳米级的混合浆料；
    (2)将所述纳米级的混合浆料进行喷雾干燥，得到干燥的前驱体混料；
    (3)将所述前驱体混料在惰性气氛下进行热处理，冷却后得到碳材料包覆金属氧化物的复合前驱体；
    (4)将所述碳材料包覆金属氧化物的复合前驱体与锂源混合后，在惰性气氛下进行高温固相反应，得到所述核壳结构富锂氧化物。
  2. 根据权利要求1所述的一种核壳结构富锂氧化物的制备方法，其特征在于：步骤(1)中，所述金属化合物为Ti、V、Cr、Mn、Fe、Ni、Co、Cu、Zn、Ga、Ge、Al、Zr、Nb、Mo、Sn或Sb的水不溶性化合物中的至少一种。
  3. 根据权利要求1所述的一种核壳结构富锂氧化物的制备方法，其特征在于：步骤(3)中，所述前驱体混料的热处理的温度为200-700℃，热处理的时间为3-15h。
  4. 根据权利要求1所述的一种核壳结构富锂氧化物的制备方法，其特征在于：步骤(4)中，所述高温固相反应的温度为300-900℃，高温固相反应的时间为6-50h。
  5. 一种核壳结构富锂氧化物，其特征在于：由权利要求1-4任一项所述的制备方法制备得到。
  6. 根据权利要求5所述的一种核壳结构富锂氧化物，其特征在于：所述核壳结构富锂氧化物包括富锂氧化物基体以及包覆在所述富锂氧化物基体表面的壳层碳材料。
  7. 根据权利要求6所述的一种核壳结构富锂氧化物，其特征在于：所述富锂氧化物基体的化学式为Li xMe aM bO y，所述Me为Ti、V、Cr、Mn、Fe、Ni、Co、Cu、Zn、Ga、Ge、Al、Zr、Nb、Mo、Sn和Sb中的至少一种；所述M为Ti、V、Cr、Mn、Fe、Ni、Co、Cu、Zn、Ga、Ge、Al、Zr、Nb、Mo、Sn和Sb中的至少一种；其中，2≤x≤6，2≤y≤4，0.5≤a≤1，0≤b≤0.5，a+b＝1。
  8. 根据权利要求7所述的一种核壳结构富锂氧化物，其特征在于：所述Me和M的平均价态为z，其中z＝2y-x。
  9. 根据权利要求7所述的一种核壳结构富锂氧化物，其特征在于：所述Me为Ni、Co、Mn、Fe、Cu或Al中的至少一种。
  10. 权利要求5-9任一项所述的核壳结构富锂氧化物在锂离子电池中的应用。
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