CN113871592A - Coated composite material and preparation method and application thereof - Google Patents

Coated composite material and preparation method and application thereof Download PDF

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Publication number
CN113871592A
CN113871592A CN202111120367.3A CN202111120367A CN113871592A CN 113871592 A CN113871592 A CN 113871592A CN 202111120367 A CN202111120367 A CN 202111120367A CN 113871592 A CN113871592 A CN 113871592A
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composite material
heteroatom
heat treatment
coated composite
doped carbon
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CN113871592B (en
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谭强强
夏青
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Institute of Process Engineering of CAS
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Institute of Process Engineering of CAS
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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
    • H01M4/364—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
    • H01M4/62—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

Abstract

The invention provides a coated composite material and a preparation method and application thereof, the coated composite material comprises an electrode material core and a coating layer coated on the surface of the electrode material core, the coating layer comprises an Fe-F-O compound, a heteroatom doped carbon material, a carbon nanotube compound and an amorphous carbon material, and the preparation method comprises the following steps: (1) mixing an electrode material inner core, an Fe-F-O compound, a heteroatom doped carbon material, a carbon nano tube and an organic solvent to obtain a mixed solution; (2) and (2) drying the mixed solution obtained in the step (1) and then carrying out heat treatment to obtain the coated composite material. The prepared coated composite material can improve the cycle stability, reversible specific capacity, rate capability and first coulombic efficiency of the battery, and has wide application prospect.

Description

Coated composite material and preparation method and application thereof
Technical Field
The invention belongs to the technical field of lithium ion battery materials, and particularly relates to a coated composite material and a preparation method and application thereof.
Background
With the rapid development of new energy automobiles, the lithium ion battery industry has entered a rapid development stage. The key materials influencing the performance of the lithium ion battery mainly comprise electrode materials, electrolyte, a diaphragm and the like. Among them, the electrode material is currently a major factor limiting the performance of the battery.
The lithium ion battery realizes large-scale application and simultaneously meets a series of requirements of low cost, safety, no natural resource limitation, high energy density and the like. The electrode materials of the lithium ion battery researched at present mainly comprise lithium cobaltate, lithium nickelate, lithium manganate with spinel structure, lithium nickelate, lithium iron phosphate and siliconBase materials, and the like. However, LiCoO2High cost, Co3+Toxic, and the material is structurally unstable when overcharged; LiNiO2The synthesis conditions are harsh, part of lithium sites are occupied by nickel sites, the degree of order is low, and the reversibility is poor; the silicon-based material can expand in volume during charging and discharging processes, and the stability of the material is influenced. Therefore, in order to improve the comprehensive electrochemical performance of lithium ion batteries, various methods are used to improve the electrode materials to improve the conductivity, the cycling stability, the service life, the rate capability and the like of the lithium ion batteries.
CN109305700A discloses a preparation method of a positive electrode material containing a niobium/tantalum cation disordered rock salt structure, which adopts a stable water-soluble citric acid Nb/Ta precursor to synthesize the positive electrode material containing the Nb/Ta cation disordered rock salt structure oxide by a wet chemical method. The initial discharge capacity of the obtained material is up to 250mAh/g, the rate capability and the cycle performance are excellent, and the capacity retention rate after 0.5C cycle for 100 times is more than 85%.
CN112680791A discloses a single crystal type IV-VI-VIII family lithium-rich disordered rock salt structure cathode material and a preparation method thereof, wherein the cathode material has the following general formula: li1+aTibWcNidO2Wherein, 0.1<a<0.3，0.1<b<0.4，0.1<c<0.4，0.1<d<0.4, and a +4b +6c +2d is 3. The capacity of the obtained material is higher than 257mAh/g at 0.05C multiplying power (1C ═ 200mA/g) for the first time, and then the capacity retention rate is higher than 48 percent after the charge-discharge test is carried out at 0.1C multiplying power after the cycle for 50 weeks.
CN105406067A discloses a method for preparing a titanium oxide modified lithium manganese iron phosphate positive electrode material, which modifies the surface of the lithium manganese iron phosphate positive electrode material with titanium dioxide to improve the cycle life and stability of the lithium manganese iron phosphate positive electrode material.
However, the reversible specific capacity, rate capability and cycle performance of the electrode material obtained by the scheme are all to be improved, so that the development of a lithium ion battery electrode material with more excellent performance has important significance in the field.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a coated composite material and a preparation method and application thereof. The electrode material synthesized by the invention can improve the cycle stability, reversible specific capacity, rate capability and first coulomb efficiency of the battery when being applied to the lithium ion battery, and has wide application prospect.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a coated composite material, which comprises an electrode material core and a coating layer coated on the surface of the electrode material core, wherein the coating layer comprises an Fe-F-O compound, a heteroatom-doped carbon material, a carbon nanotube composite and an amorphous carbon material.
The invention uses Fe-F-O compound, heteroatom doped carbon material, carbon nano tube and amorphous carbon material as cladding to construct cladding, the four materials have synergistic effect and are cladded on the surface of an electrode, the cycle stability, reversible specific capacity, rate capability and first coulomb efficiency of the cladded composite material can be improved, and the technical principle is as follows: the first, Fe-F-O compound has the ability of releasing and inserting lithium, and is used for the coating layer, which not only provides a physical barrier layer between the electrode and the electrolyte, inhibits the side reaction, but also improves the charge transfer kinetics, is beneficial to the transmission of lithium ions between the electrode material core and the electrolyte, and enables the coating type composite material to have better electrochemical performance. Secondly, the heteroatom doped carbon material and the carbon nano tube have good conductive capability, so that the electronic conductivity of the inner core of the electrode material can be improved, and the overall conductivity of the material is improved; meanwhile, the heteroatom doped carbon material and the carbon nano tube have the advantages of high mechanical property, good thermal stability and the like, can keep stable structure after charge/discharge cycle, and improves the cycle stability of the material. Thirdly, the amorphous carbon can bond the material particles and improve the stability of the whole material.
Preferably, the electrode material core is a positive electrode material core or a negative electrode material core, and the coating layer can achieve a good coating effect on both the positive electrode material core and the negative electrode material core, and is preferably the positive electrode material core.
Preferably, the core of the cathode material is disorderedSalt structure of squaraine, in which the anion (O)2-And F-) Occupying the sites of the face centered cubic lattice, and cations (lithium ions and transition metal ions) randomly occupy the face centered cubic sublattices of the octahedral voids.
Preferably, the chemical formula of the cathode material core with the disordered cubic rock salt structure is Li1+xM1-xO2-yFyWherein x is 0.1. ltoreq. x.ltoreq.0.3, for example, 0.1, 0.15, 0.2, 0.25, or 0.3, etc., y is 0 < y.ltoreq.0.3, for example, 0.05, 0.1, 0.15, 0.2, 0.25, or 0.3, etc., and M is a transition metal element.
Preferably, the transition metal element is any one or a combination of at least two of Mn, Ni, V, Mo, Fe, Ti, Zr, Cr, Co, Cu, Zn, Nb, Sc, or Y, and may be, for example, Mn, Ni, V, a combination of Fe and Ti, a combination of Zr and Cr, or a combination of Fe, Co and Ti, and the like, and is preferably any one or a combination of at least two of Mn, Ni, V, Mo, Fe, or Ti.
Preferably, the Fe-F-O composition is FeFxAt least one of (1) and FeyOzWherein 2. ltoreq. x.ltoreq.3, for example 2 or 3, 0<y.ltoreq.3, for example 0.5, 1, 2 or 3, 1. ltoreq.z.ltoreq.4, for example 1, 2, 3 or 4.
In an alternative embodiment, the Fe-F-O composition may specifically be FeF2And/or FeF3With FeO, Fe2O3Or Fe3O4At least one of (a) and (b). For example, FeF may be used2And Fe2O3Composition formed, FeF2Composition formed with FeO, FeF2And Fe3O4Composition formed, FeF2、FeF3And Fe3O4Composition formed, FeF3、Fe2O3And Fe3O4The resulting composition, or FeF2、FeF3And Fe2O3The resulting composition, and the like.
Preferably, the Fe-F-O compound is FeFxAnd FeyOzFormed ofWherein x is more than or equal to 2 and less than or equal to 3, y is more than or equal to 2 and less than or equal to 3, and z is more than or equal to 3 and less than or equal to 4, and the Fe-F-O composition can be FeF2And Fe2O3Of FeF2And Fe3O4Of FeF3And Fe2O3Of FeF3And Fe3O4The composition of (1).
Preferably, the Fe-F-O composition is FeF2、FeF3、Fe2O3And Fe3O4The resulting composition.
Preferably, the heteroatom-doped carbon material is a boron, nitrogen, sulfur and phosphorus co-doped carbon material.
Preferably, the atomic ratio of boron, nitrogen, sulfur and phosphorus in the boron, nitrogen, sulfur and phosphorus co-doped carbon material is (0.5-1): (1-2): (0.5-1), wherein the selection range of boron (0.5-1) can be, for example, 0.5, 0.6, 0.8 or 1, the selection range of nitrogen (1-2) can be, for example, 1, 1.2, 1.5, 1.8 or 2, etc., the selection range of sulfur (1-2) can be, for example, 1, 1.2, 1.5, 1.8 or 2, etc., and the selection range of phosphorus (0.5-1) can be, for example, 0.5, 0.6, 0.8 or 1, etc.
The heteroatoms of the heteroatom-doped carbon material have a synergistic effect, can provide short-range ultrafast electronic conductance, and can buffer the volume change of the inner core of the electrode material in the circulating process. By optimizing the atomic ratio of four atoms of boron, nitrogen, sulfur and phosphorus in the heteroatom doped carbon material, the microstructure of the heteroatom doped carbon material can be improved, and the electronic conductance of the heteroatom doped carbon material can be improved.
Preferably, the carbon nanotubes are single-walled carbon nanotubes and/or multi-walled carbon nanotubes, preferably multi-walled carbon nanotubes.
Preferably, the carbon nanotubes have an aspect ratio of 500-.
As a preferable technical scheme of the coating type composite material, the particle size of the electrode material core is 100-2000nm, for example, 100nm, 200nm, 300nm, 500nm, 1000nm, 1500nm or 2000nm, preferably 300-1000 nm.
The particle size of the electrode material core can influence the electrochemical performance of the coated composite material, when the particle size of the electrode material core is smaller, agglomeration is easily caused, the structure and the stability of the material are damaged, and when the particle size difference between the electrode material core and the outer layer particles is too small, a uniform coating layer is difficult to form on the surface of the coated material; when the particle size of the electrode material core is large, the electrochemical activity of the clad composite material is reduced.
Preferably, the particle size of the Fe-F-O compound is 20 to 100nm, and may be, for example, 20nm, 30nm, 50nm, 80nm, 100nm, or the like.
Preferably, the content of the electrode material core is 82 to 98.4%, for example, 82%, 85%, 87%, 90%, 92%, 95%, 97%, 98.4%, or the like, preferably 90 to 97%, based on 100% by mass of the coated composite material.
Preferably, the content of the Fe — F — O compound is 0.5 to 5%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, or 5%, preferably 1 to 3%, based on 100% by mass of the coated composite material.
Preferably, the content of the heteroatom-doped carbon material is 0.5 to 4%, for example, 0.5%, 1%, 2%, 2.5%, 3%, 3.5%, or 4%, preferably 1 to 3%, based on 100% by mass of the coated composite material.
Preferably, the content of the carbon nanotubes is 0.5 to 5%, for example, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or the like, preferably 0.5 to 2%, based on 100% by mass of the coated composite material.
Preferably, the content of the amorphous carbon material is 0.1 to 4%, for example, 0.1%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, or the like, preferably 0.5 to 2%, based on 100% by mass of the coated composite material.
Preferably, the FeF is 100% of the Fe-F-O composition by massxThe content of (A) is 70 to 90%, and may be, for example, 70%, 75%, 80%, 85%, 90%, or the like.
The electrochemical performance of the coated composite material can be influenced by the contents of the Fe-F-O compound, the heteroatom doped carbon material and the carbon nano tube, and when the contents of the Fe-F-O compound, the heteroatom doped carbon material and the carbon nano tube in the coating layer are too high, the transmission of lithium ions between interfaces can be hindered, and the integral specific capacity of the material can be reduced; when the coating content is too low, the effects of stabilizing the material structure, improving the rate capability and the first coulombic efficiency cannot be achieved.
Preferably, the coating layer is coated on part of or all of the surface of the electrode material core, and can play a role in improving the cycling stability, reversible specific capacity, rate capability and initial coulomb efficiency of the material.
In a second aspect, the present invention provides a process for the preparation of a clad composite material as defined in the first aspect, said process comprising the steps of:
(1) mixing an electrode material inner core, an Fe-F-O compound, a heteroatom doped carbon material, a carbon nano tube and an organic solution to obtain a mixed solution;
(2) and (2) drying the mixed solution obtained in the step (1) and then carrying out heat treatment to obtain the coated composite material.
According to the invention, the organic solvent is used as the carbon source and the solvent, so that the dispersibility of the electrode material core, the Fe-F-O compound, the heteroatom doped carbon material and the carbon nano tube is ensured, the organic solvent is converted into amorphous carbon after drying and heat treatment, and the prepared coated composite material has the advantages that the Fe-F-O compound, the heteroatom doped carbon material, the carbon nano tube and the amorphous carbon have good associativity and can form a stable coating layer, meanwhile, the coating layer formed by the four is uniformly coated on the surface of the electrode material core, so that the dispersibility is good, the structural stability of the electrode material core in the charge-discharge process can be enhanced, the volume change of the material is relieved, and the first coulomb efficiency, reversible capacity, rate capability and cycle stability of the coated composite material are improved.
Preferably, the heteroatom-doped carbon material prepared in the step (1) is prepared by the following steps: mixing boric acid, a nitrogen source, a sulfur source, a phosphorus source and a carbon source, transferring the mixture into a closed container, filling protective gas into the closed container, carrying out heat treatment on the closed container in the protective gas, and cooling to obtain the heteroatom doped carbon material.
Preferably, the nitrogen source is melamine and/or nitrilotriacetic acid, which may be, for example, melamine, nitrilotriacetic acid or a combination of melamine and nitrilotriacetic acid.
Preferably, the sulfur source is any one or a combination of at least two of sodium sulfide, sodium thiosulfate, thiourea, thiol, thiophenol, thioether, disulfide, polysulfide or cyclic sulfide, and may be, for example, sodium sulfide, sodium thiosulfate, thiourea, thiol, thiophenol, thioether, disulfide, polysulfide, cyclic sulfide, a combination of sodium sulfide and sodium thiosulfate, a combination of thiourea and thiol, a combination of disulfide and polysulfide, a combination of sodium thiosulfate, thiourea and thiol, a combination of thiophenol, thioether and disulfide, a combination of sodium thiosulfate, thiourea, thiol and thiophenol, or a combination of thiol, thiophenol, thioether, disulfide and polysulfide.
Preferably, the phosphorus source is any one or a combination of at least two of phosphonitrile trichloride chloride, adenosine triphosphate, adenosine diphosphate, phosphoenone pyruvate, phosphate ester, tetrakis hydroxymethyl phosphonium chloride, dimethyl vinylphosphate, hexachlorocyclotriphosphazene, polydichlorophosphazene, polyalkoxyphosphazene, polyaryloxy phosphazene or polyfluorooxyphosphazene, and may be, for example, phosphonitrile trichloride chloride, adenosine triphosphate, adenosine diphosphate, a combination of adenosine diphosphate and phosphoenone pyruvate, tetrakis hydroxymethyl phosphonium chloride, dimethyl vinylphosphate and hexachlorocyclotriphosphazene, dimethyl vinylphosphate, hexachlorocyclotriphosphazene, polydichlorophosphazene and polyalkoxyphosphazene, or a combination of adenosine diphosphate, phosphoenone pyruvate, phosphate ester, tetrakis hydroxymethyl phosphonium chloride and dimethyl vinylphosphate.
Preferably, the carbon source is any one of polyvinylpyrrolidone, poly (4-vinylpyridine) or polyethylene terephthalate or a combination of at least two thereof, and may be, for example, polyvinylpyrrolidone, poly (4-vinylpyridine), polyethylene terephthalate, a combination of polyvinylpyrrolidone and poly (4-vinylpyridine) or a combination of polyvinylpyrrolidone, poly (4-vinylpyridine) and polyethylene terephthalate.
Preferably, in the method for preparing the heteroatom-doped carbon material, the protective atmosphere is any one or a combination of at least two of nitrogen, argon or helium, and may be, for example, nitrogen, argon, a combination of argon and helium or a combination of nitrogen, argon and helium.
Preferably, in the preparation method of the heteroatom-doped carbon material, the temperature of the heat treatment is 350-500 ℃, and can be 350 ℃, 400 ℃, 450 ℃ or 500 ℃ and the like.
Preferably, in the preparation method of the heteroatom doped carbon material, the heat treatment holding time is 1-4h, such as 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4 h.
Preferably, in the method for preparing the heteroatom-doped carbon material, the heating rate of the heat treatment is 2-10 ℃/min, and for example, the heating rate can be 2 ℃/min, 4 ℃/min, 6 ℃/min, 8 ℃/min or 10 ℃/min.
As a preferred embodiment of the preparation method of the present invention, the mixing in step (1) is performed in the following manner: dispersing the electrode material inner core, the Fe-F-O compound, the heteroatom doped carbon material and the carbon nano tube in an organic solution, and performing ultrasonic dispersion uniformly.
Preferably, the organic solution is any one of or a combination of at least two of ethylene glycol, glycerol or phenolic resin, and may be, for example, ethylene glycol, glycerol, phenolic resin, a combination of ethylene glycol and glycerol, a combination of glycerol and phenolic resin or a combination of ethylene glycol, glycerol and phenolic resin.
The preferable organic solvents of ethylene glycol, glycerol and phenolic resin in the invention have certain viscosity, can realize uniform dispersion of particles, can be carbonized in the heat treatment process to generate amorphous carbon, realize uniform coating and play a role in bonding the particles.
Preferably, the power of the ultrasound is 150-250W, such as 150W, 180W, 200W, 220W or 250W, and the like, and the time of the ultrasound is 20-60min, such as 20min, 30min, 40min, 50min or 60min, and the like.
Preferably, the drying in the step (2) is spray drying, and granulation can be performed while drying, so that uniform coating of the coating layer is realized, particle agglomeration is reduced, and the effect is better than that of a common drying mode.
Preferably, the outlet temperature of the spray drying is 100 ℃ and 250 ℃, for example, 100 ℃, 110 ℃, 120 ℃, 150 ℃, 180 ℃, 200 ℃, 230 ℃ or 250 ℃ and the like can be used.
The outlet temperature of the spray drying in the invention can influence the electrochemical performance of the material, when the temperature is too low, the coated composite material cannot be dried fully, and the uniform granulation effect cannot be realized, and when the temperature is too high, the uniform granulation degree can be influenced, and the electrochemical performance of the material is further influenced.
Preferably, the heat treatment of step (2) is performed under a protective atmosphere.
Preferably, the gas in the protective atmosphere in step (2) is any one or a combination of at least two of nitrogen, argon or helium, and may be, for example, nitrogen, argon, helium, a combination of nitrogen and argon, a combination of argon and helium, a combination of nitrogen, argon and helium, or the like.
Preferably, the temperature of the heat treatment in step (2) is 300-.
Preferably, the heating rate of the heat treatment in step (2) is 1-10 deg.C/min, such as 1 deg.C/min, 2 deg.C/min, 4 deg.C/min, 6 deg.C/min, 8 deg.C/min, or 10 deg.C/min.
Preferably, the heat treatment in step (2) has a holding time of 0.5 to 6 hours, such as 0.5 hour, 0.8 hour, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours or 6 hours, preferably 1 to 4 hours.
In the invention, the heat treatment temperature in the step (2) can influence the electrochemical performance of the material, and when the heat treatment temperature is too low, the solvent cannot be completely carbonized, and the effects of bonding particles and conducting electricity cannot be achieved; when the heat treatment temperature is too high, the crystal grains grow along with the heat treatment temperature, and the lithium ion diffusion path is enlarged.
As a further preferable technical scheme of the preparation method of the invention, the preparation method comprises the following steps:
(1) uniformly mixing boric acid, a nitrogen source, a sulfur source, a phosphorus source and a carbon source, and transferring the mixture into a closed container to make up for the fact that the container is filled with protective gas; carrying out heat treatment on the closed container at the temperature of 350-500 ℃ for 1-4h, wherein the heating rate of the heat treatment is 2-10 ℃/min, and cooling to obtain the heteroatom doped carbon material;
(2) dispersing an electrode material inner core, an Fe-F-O compound, a heteroatom doped carbon material and a carbon nano tube in an organic solution, and performing ultrasonic dispersion uniformly to obtain a mixed solution;
(3) and (3) spray-drying the mixed solution in the step (2) at the temperature of 100-250 ℃, then carrying out heat treatment in a protective atmosphere, heating to the temperature of 300-600 ℃ at the heating rate of 1-10 ℃/min for heat treatment for 0.5-6h, and cooling to obtain the coating composite material.
In a third aspect, the present invention provides a lithium ion battery comprising the clad composite material according to the first aspect.
Compared with the prior art, the invention has the following beneficial effects:
(1) according to the invention, the Fe-F-O compound, the heteroatom doped carbon material, the carbon nano tube and the amorphous carbon material are used for constructing the coating layer, a physical barrier layer is provided between the electrode and the electrolyte, side reaction is inhibited, charge transfer kinetics is improved, the composite anode material has better electrochemical performance, and meanwhile, the four components have synergistic effect, so that the cycle stability, reversible specific capacity, rate capability and initial coulomb efficiency of the coated composite material are improved.
(2) The invention adopts a spray drying method to directly granulate the obtained coated composite material, so that the obtained coated composite material has uniform coating and uniform particle size.
(3) The preparation method of the coated composite material provided by the invention has the advantages of simple process, low requirement on equipment and relatively low cost, and is suitable for industrial production.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
Example 1
The embodiment provides a coated composite material, which comprises an electrode material core and a coating layer coated on the surface of the electrode material core, wherein the coating layer comprises a Fe-F-O compound, a heteroatom-doped carbon material, a carbon nanotube composite and an amorphous carbon material, and the electrode material core is Li1.2Mo0.7Ti0.1O1.8F0.2The grain diameter is 1000nm, and the Fe-F-O compound is FeF with the mass ratio of 7:33And Fe2O3The average particle size of the composition is 50nm, the heteroatom doped carbon material is a boron, nitrogen, sulfur and phosphorus co-doped composite carbon material, the atomic ratio of boron, nitrogen, sulfur and phosphorus is 0.8:1.5:1.5:0.8, and the length-diameter ratio of the carbon nano tube is 1500.
The mass of the coated composite material is 100%, the content of an electrode material core in the coated composite material is 93%, the mass of the Fe-F-O compound is 2%, the mass of the heteroatom doped carbon material is 3%, the mass of the carbon nano tube is 1%, and the mass of the amorphous carbon material is 1%. The preparation method of the coated composite material comprises the following steps:
(1) mixing boric acid, melamine, sodium sulfide, tetrakis (hydroxymethyl) phosphonium chloride, polyvinylpyrrolidone and poly (4-vinylpyridine), transferring the mixture into a closed container, filling argon into the closed container, carrying out heat treatment on the closed container at 450 ℃ for 2.5h, wherein the heating rate of the heat treatment is 6 ℃/min, and cooling to obtain a heteroatom doped carbon material;
(2) mixing Li1.2Mo0.7Ti0.1O1.8F0.2And Fe-F-O compoundThe material, the heteroatom doped carbon material and the multi-walled carbon nanotube are dispersed in glycerol and uniformly dispersed by ultrasonic; wherein the Fe-F-O compound is FeF with the mass ratio of 7:33(designation 011487) and Fe2O3(composition No. F299311);
(3) and (3) after the solution is spray-dried at the temperature of 120 ℃, carrying out heat treatment in a nitrogen atmosphere, heating to 450 ℃ at the heating rate of 5 ℃/min for heat treatment for 2h, and cooling to obtain the coated composite material.
Example 2
The embodiment provides a coated composite material, which comprises an electrode material core and a coating layer coated on the surface of the electrode material core, wherein the coating layer comprises a Fe-F-O compound, a heteroatom-doped carbon material, a carbon nanotube composite and an amorphous carbon material, and the electrode material core is Li1.1Fe0.6V0.3O1.8F0.2The grain diameter is 100nm, and the Fe-F-O compound is FeF with the mass ratio of 8:1:12、FeF3And Fe3O4The average particle size of the composition is 100nm, the heteroatom doped carbon material is a boron, nitrogen, sulfur and phosphorus co-doped composite carbon material, the atomic ratio of boron, nitrogen, sulfur and phosphorus is 0.5:1:2:0.5, and the length-diameter ratio of the carbon nano tube is 500.
The mass content of the core of the electrode material in the coated composite material is 94.4%, the mass content of the Fe-F-O compound is 3%, the mass content of the heteroatom doped carbon material is 0.5%, the mass content of the carbon nano tube is 2%, and the mass content of the amorphous carbon material is 0.1%, wherein the mass content of the coated composite material is 100%.
The preparation method of the coated composite material comprises the following steps:
(1) mixing boric acid, melamine, nitrilotriacetic acid, thiourea, mercaptan and adenosine triphosphate, transferring the mixture into a closed container, filling helium into the closed container, carrying out heat treatment on the closed container at 450 ℃ for 2 hours at the heating rate of 10 ℃/min, and cooling to obtain a heteroatom doped carbon material;
(2) mixing Li1.1Fe0.6V0.3O1.8F0.2Dispersing the Fe-F-O compound, the heteroatom doped carbon material and the single-walled carbon nanotube in ethylene glycol, and uniformly dispersing by ultrasonic; wherein the Fe-F-O compound is FeF with the mass ratio of 8:1:12(brand I836769), FeF3(designation I836755) and Fe3O4(composition of the brand I903424);
(2) and (3) after the solution is spray-dried at the temperature of 100 ℃, carrying out heat treatment in an argon atmosphere, heating to 600 ℃ at the heating rate of 10 ℃/min for heat treatment for 0.5h, and cooling to obtain the coated composite material.
Example 3
The embodiment provides a coated composite material, which comprises an electrode material core and a coating layer coated on the surface of the electrode material core, wherein the coating layer comprises a Fe-F-O compound, a heteroatom-doped carbon material, a carbon nanotube composite and an amorphous carbon material, and the electrode material core is Li1.3Mn0.7O1.7F0.3The grain diameter is 2000nm, and the Fe-F-O compound is FeF with the mass ratio of 8:1:13、Fe2O3And Fe3O4The average particle size of the composition is 50nm, the heteroatom doped carbon material is a boron, nitrogen, sulfur and phosphorus co-doped composite carbon material, the atomic ratio of boron, nitrogen, sulfur and phosphorus is 1:2:1:0.5, and the length-diameter ratio of the carbon nano tube is 3000.
The mass content of the core of the electrode material in the coated composite material is 92.5%, the mass content of the Fe-F-O compound in the coated composite material is 1%, the mass content of the heteroatom doped carbon material is 4%, the mass content of the carbon nano tube is 0.5%, and the mass content of the amorphous carbon material is 2%, wherein the mass content of the coated composite material is 100%.
The preparation method of the coated composite material comprises the following steps:
(1) mixing boric acid, nitrilotriacetic acid, thioether, hexachlorocyclotriphosphazene, polyvinylpyrrolidone, poly (4-vinylpyridine) and polyethylene glycol terephthalate, transferring the mixture into a closed container, filling nitrogen into the closed container, carrying out heat treatment on the closed container at 400 ℃ for 3 hours at the heating rate of 8 ℃/min, and cooling to obtain a heteroatom doped carbon material;
(2) mixing Li1.3Mn0.7O1.7F0.3The Fe-F-O compound, the heteroatom doped carbon material and the multi-walled carbon nanotube are dispersed in the phenolic resin and uniformly dispersed by ultrasonic; wherein the Fe-F-O compound is FeF with the mass ratio of 8:1:13(designation 011487), Fe2O3(designation F299311) and Fe3O4(composition under the designation I119031);
(3) and (3) after the solution is spray-dried at the temperature of 250 ℃, carrying out heat treatment in a nitrogen atmosphere, heating to 300 ℃ at the heating rate of 1 ℃/min for heat treatment for 6h, and cooling to obtain the coated composite material.
Example 4
The embodiment provides a coated composite material, which comprises an electrode material core and a coating layer coated on the surface of the electrode material core, wherein the coating layer comprises a Fe-F-O compound, a heteroatom-doped carbon material, a carbon nanotube composite and an amorphous carbon material, and the electrode material core is Li1.1Mn0.8V0.05Ni0.05O1.9F0.1The grain diameter is 500nm, and the Fe-F-O compound is FeF with the mass ratio of 5:4:13And Fe2O3The average particle size of the composition is 20nm, the heteroatom doped carbon material is a boron, nitrogen, sulfur and phosphorus co-doped composite carbon material, the atomic ratio of boron, nitrogen, sulfur and phosphorus is 1:2:1:0.5, and the length-diameter ratio of the carbon nano tube is 2000.
The mass content of the core of the electrode material in the coated composite material is 95.42%, the mass content of the Fe-F-O compound in the coated composite material is 1.35%, the mass content of the heteroatom doped carbon material is 1.8%, the mass content of the carbon nano tube is 0.85%, and the mass content of the amorphous carbon material is 0.58%, wherein the mass content of the coated composite material is 100%.
The preparation method of the coated composite material comprises the following steps:
(1) mixing boric acid, melamine, nitrilotriacetic acid, sodium thiosulfate, thiourea, mercaptan, dimethyl vinylphosphate, hexachlorocyclotriphosphazene and polyethylene glycol terephthalate, transferring into a closed container, filling argon and helium into the closed container, carrying out heat treatment on the closed container at 500 ℃ for 1h, wherein the heating rate of the heat treatment is 2 ℃/min, and cooling to obtain a heteroatom doped carbon material;
(2) mixing Li1.1Mn0.8V0.05Ni0.05O1.9F0.1The Fe-F-O compound, the heteroatom doped carbon material and the multi-walled carbon nanotube are dispersed in glycerol and uniformly dispersed by ultrasonic; wherein the Fe-F-O compound is FeF with the mass ratio of 5:4:13(designation I836755) and Fe2O3(composition under the designation F809546);
(3) and (3) spray-drying the solution at the temperature of 150 ℃, then carrying out heat treatment in an argon atmosphere, heating to 400 ℃ at the heating rate of 4 ℃/min for heat treatment for 4h, and cooling to obtain the coated composite material.
Example 5
The embodiment provides a coated composite material, which comprises an electrode material core and a coating layer coated on the surface of the electrode material core, wherein the coating layer comprises a Fe-F-O compound, a heteroatom-doped carbon material, a carbon nanotube composite and an amorphous carbon material, and the electrode material core is Li1.2V0.7Cr0.1O1.98F0.02The grain diameter is 400nm, and the Fe-F-O compound is FeF with the mass ratio of 5:3:1:12、FeF3、Fe2O3And Fe3O4The average particle size of the composition is 60nm, the heteroatom doped carbon material is a boron, nitrogen, sulfur and phosphorus co-doped composite carbon material, the atomic ratio of boron, nitrogen, sulfur and phosphorus is 0.5:1.5:1.5:1, and the length-diameter ratio of the carbon nano tube is 1800.
The mass content of the core of the electrode material in the coated composite material is 94.3%, the mass content of the Fe-F-O compound in the coated composite material is 1%, the mass content of the heteroatom doped carbon material is 1.5%, the mass content of the carbon nano tube is 2%, and the mass content of the amorphous carbon material is 1.2%, wherein the mass content of the coated composite material is 100%.
The preparation method of the coated composite material comprises the following steps:
(1) mixing boric acid, melamine, sodium thiosulfate, vinyl dimethyl phosphate and polyvinylpyrrolidone, transferring the mixture into a closed container, filling nitrogen, argon and helium into the closed container, carrying out heat treatment on the closed container at 350 ℃ for 4 hours at the heating rate of 4 ℃/min, and cooling to obtain a heteroatom-doped carbon material;
(2) mixing Li1.2V0.7Cr0.1O1.98F0.02The Fe-F-O compound, the heteroatom doped carbon material and the multi-walled carbon nanotube are dispersed in ethylene glycol and uniformly dispersed by ultrasonic; wherein the Fe-F-O compound is FeF with the mass ratio of 5:3:1:12(brand I836755), FeF3(designation I836755), Fe2O3(designation F809546) and Fe3O4(composition of the brand I903421);
(3) and (3) after the solution is spray-dried at the temperature of 180 ℃, carrying out heat treatment in a helium atmosphere, heating to 500 ℃ at the heating rate of 8 ℃/min for 5h, and cooling to obtain the coated composite material.
Example 6
The embodiment provides a coated composite material, which comprises an electrode material core and a coating layer coated on the surface of the electrode material core, wherein the coating layer comprises a Fe-F-O compound, a heteroatom-doped carbon material, a carbon nanotube composite and an amorphous carbon material, and the electrode material core is Li1.2V0.7Cr0.1O1.99F0.01The grain diameter is 1600nm, and the Fe-F-O compound is FeF with the mass ratio of 8:23And Fe3O4The average particle size of the composition is 50nm, the heteroatom doped carbon material is a boron, nitrogen, sulfur and phosphorus co-doped composite carbon material, the atomic ratio of boron, nitrogen, sulfur and phosphorus is 1:1:1, and the length-diameter ratio of the carbon nano tube is 1200.
The mass content of the core of the electrode material in the coated composite material is 93.2%, the mass content of the Fe-F-O compound in the coated composite material is 2%, the mass content of the heteroatom doped carbon material is 2.5%, the mass content of the carbon nano tube is 1.5%, and the mass content of the amorphous carbon material is 0.8%, wherein the mass content of the coated composite material is 100%.
The preparation method of the coated composite material comprises the following steps:
(1) mixing boric acid, nitrilotriacetic acid, thioether, hexachlorocyclotriphosphazene, polyvinylpyrrolidone, poly (4-vinylpyridine) and polyethylene glycol terephthalate, transferring the mixture into a closed container, filling nitrogen into the closed container, carrying out heat treatment on the closed container at 400 ℃ for 3 hours at the heating rate of 8 ℃/min, and cooling to obtain a heteroatom doped carbon material;
(2) mixing Li1.2V0.7Cr0.1O1.99F0.01The Fe-F-O compound, the heteroatom doped carbon material and the multi-walled carbon nanotube are dispersed in the phenolic resin and uniformly dispersed by ultrasonic; wherein the Fe-F-O compound is FeF with the mass ratio of 8:23(designation I836755) and Fe3O4(composition of the brand I903421);
(3) and (3) after the solution is spray-dried at the temperature of 160 ℃, carrying out heat treatment in a helium atmosphere, heating to 450 ℃ at the heating rate of 4 ℃/min for heat treatment for 1.5h, and cooling to obtain the coating composite material.
Example 7
This example provides a coated composite material and a method for producing the same, which are the same as those of example 1 except that the spray drying in step (3) is replaced with the ordinary drying.
Example 8
This example provides a clad composite and a method for preparing the same as in example 1, except that the temperature of the heat treatment in step (3) was 200 ℃.
Example 9
This example provides a clad composite and a method for preparing the same as in example 1, except that the temperature of the heat treatment in step (3) was 700 ℃.
Example 10
This example provides a coated composite material and a method for preparing the same, except for Li in the coated composite material1.2Mo0.7Ti0.1O1.8F0.2The particle diameter of (2) was not more than 50nm, and the same as in example 1 was repeated.
Example 11
This example provides a coated composite material and a method for preparing the same, except for Li in the coated composite material1.2Mo0.7Ti0.1O1.8F0.2Has a particle diameter of 3000 nm.
Example 12
This example provides a coated composite material and a method for preparing the same, except that the particle size of the Fe-F-O compound in the coated composite material is 200nm, as in example 1.
Example 13
This example provides a coated composite material and a method for preparing the same, except that the aspect ratio of the carbon nanotubes in the coated composite material is 200, the same as in example 1.
Example 14
This example provides a coated composite material and a method for preparing the same, except that the aspect ratio of the carbon nanotubes in the coated composite material is 4000, the same as in example 1.
Example 15
This example provides a coated composite material and a method for preparing the same, except that the atomic ratio of boron, nitrogen, sulfur, and phosphorus in the heteroatom-doped carbon material is 1.7:1.5:1.5:0.8, the rest being the same as in example 1.
Example 16
This example provides a coated composite material and a method for preparing the same, except that the atomic ratio of boron, nitrogen, sulfur, and phosphorus in the heteroatom-doped carbon material is 0.8:3.5:1.5:0.8, the rest being the same as in example 1.
Example 17
This example provides a coated composite material and a method for preparing the same, except that the atomic ratio of boron, nitrogen, sulfur, and phosphorus in the heteroatom-doped carbon material is 0.8:1.5:3.5:0.8, the remainder being the same as in example 1.
Example 18
This example provides a coated composite material and a method for preparing the same, except that the atomic ratio of boron, nitrogen, sulfur, and phosphorus in the heteroatom-doped carbon material is 0.8:1.5:1.5:1.7, the rest being the same as in example 1.
Example 19
This example provides a coated composite material and a method for preparing the same, except that the atomic ratio of nitrogen, sulfur and phosphorus in the heteroatom-doped carbon material is 1.5:1.5:0.8, the rest being the same as in example 1.
Example 20
This example provides a coated composite material and a method for preparing the same, except that the atomic ratio of boron, sulfur and phosphorus in the heteroatom-doped carbon material is 0.8:1.5:0.8, the rest being the same as in example 1.
Example 21
This example provides a coated composite material and a method for preparing the same, except that the atomic ratio of boron, nitrogen and phosphorus in the heteroatom-doped carbon material is 0.8:1.5:0.8, the rest being the same as in example 1.
Example 22
This example provides a coated composite material and a method for preparing the same, except that the atomic ratio of boron, nitrogen and sulfur in the heteroatom-doped carbon material is 0.8:1.5:1.5, the rest is the same as example 1.
Example 23
This example provides a coated composite material and a method for preparing the same, except that the content of the Fe — F — O compound in the coated composite material is 6%, the same as in example 1.
Example 24
This example provides a coated composite material and a method for preparing the same, except that the content of the heteroatom-doped carbon material in the coated composite material is 8%, the rest is the same as that in example 1.
Example 25
This example provides a coated composite material and a method for preparing the same, except that the carbon nanotube content in the coated composite material is 4%, the same as in example 1.
Comparative example 1
This comparative example provides a coated composite material and a method for producing the same as in example 1 except that the coated composite material does not contain the Fe-F-O compound.
Comparative example 2
This comparative example provides a coated composite material and a method for producing the same as in example 1 except that the coated composite material does not contain a heteroatom-doped carbon material.
Comparative example 3
This comparative example provides a coated composite material and a method for producing the same as in example 1 except that the coated composite material does not contain a multi-walled carbon nanotube.
Comparative example 4
This comparative example provides a coated composite material and a method for producing the same, which are the same as in example 1 except that glycerol in step (2) was replaced with deionized water.
The coating layer of the coated composite material prepared by the comparative example does not contain amorphous carbon.
Electrochemical performance tests were performed on the coated composite materials provided in examples 1-25 and comparative examples 1-4, and the pole piece ratio was 90:5:5, mass ratio of acetylene black to PVDF. 1mol/L LiPF with metal lithium sheet as counter electrode and polypropylene microporous membrane Celgard 2400 as diaphragm6Preparing a CR2025 type button cell by using/EC + DEC + DMC (volume ratio of 1:1:1) as an electrolyte. And (3) performing constant-current charge and discharge test on the battery by adopting a LAND battery test system: the voltage range is 1.5-5.0V, the current density is 50mA/g and 200mA/g respectively, the capacity retention rate is obtained by testing the charge-discharge cycle for 200 circles under the current density of 50mA/g, and the test results are shown in Table 1.
TABLE 1
Figure BDA0003276873910000201
Figure BDA0003276873910000211
Figure BDA0003276873910000221
The rate performance was characterized by the capacity tested at 50mA/g and 200mA/g current densities.
It can be seen from the above examples 1-25 that the cycling stability, reversible specific capacity, rate capability and first coulombic efficiency of the electrode material can be improved by the synergistic effect of the Fe-F-O compound, the heteroatom doped carbon material, the carbon nanotube and the amorphous carbon to construct the coating layer.
It can be seen from the comparison between example 1 and example 7 that when the coated composite material is prepared by the method provided by the present invention, spray drying is the best drying method, which can perform granulation while drying, so as to achieve uniform coating, reduce particle agglomeration, and further improve the comprehensive electrochemical performance.
As can be seen from the comparison between example 1 and examples 8-9, the heat treatment temperature in step (3) affects the electrochemical properties of the material, and the heat treatment temperature has a preferred range, and when the heat treatment temperature is too low, the solvent cannot be completely carbonized, and the effects of bonding particles and conducting electricity cannot be achieved; when the heat treatment temperature is too high, crystal grains grow along with the heat treatment temperature, and a lithium ion diffusion path is enlarged.
As can be seen from the comparison between example 1 and examples 10-11, the particle size of the core of the positive electrode material in the coated composite material affects the electrochemical performance of the material, when the particle size is smaller, agglomeration is easily caused, and the particle size difference between the core and the outer layer is too small, so that a uniform coating layer is difficult to form on the core of the positive electrode material, and the electrochemical performance, particularly the first coulombic efficiency and the cycle performance are reduced; when the particle size is larger, the electrochemical activity is reduced, resulting in a reduction in the overall electrochemical performance of the electrode material.
It is understood from a comparison between example 1 and example 12 that when the particle size of the Fe — F — O compound in the coated composite material is too large, the particle activity is lowered, and it is difficult to form a uniform coating layer, resulting in a decrease in electrochemical performance of the coated composite material.
As can be seen from the comparison between example 1 and examples 13-14, when the aspect ratio of the carbon nanotubes in the coated composite material is too short, a long-range conductive path cannot be formed, which is not favorable for constructing a stable material structure, and leads to the reduction of electrochemical performance, especially cycle performance; when the length-diameter ratio is too long, winding occurs, a uniform coating structure is difficult to form, and the electrochemical performance of the electrode material is reduced.
It can be seen from the comparison between example 1 and examples 15-18 that the heteroatom-doped carbon material has an optimal ratio of atoms of boron, nitrogen, sulfur and phosphorus, and an excessively large or excessively small ratio affects the microstructure of the heteroatom-doped carbon material, affects the electronic conductivity of the heteroatom-doped carbon material, and further affects the electrochemical performance of the electrode material.
It is understood from the comparison between example 1 and examples 19 to 22 that the doping type of the heteroatom in the heteroatom-doped carbon material affects the electrochemical performance of the positive electrode material, and the heteroatom has a synergistic effect, so that the effect of the present invention cannot be achieved in the absence of the heteroatom.
It can be seen from the comparison between example 1 and examples 23-25 that the contents of the Fe-F-O compound, the heteroatom-doped carbon material and the carbon nanotubes in the coated composite material affect the electrochemical performance of the material, and when the coating content is too high, the transmission of lithium ions between interfaces is hindered, and the specific capacity of the whole material is reduced.
It is understood from the comparison between example 1 and comparative examples 1 to 3 that the absence of the Fe — F — O compound, the heteroatom-doped carbon material, and the carbon nanotube in the coating layer of the positive electrode material all have a bad effect on the electrochemical performance of the positive electrode material, and the expected result can be obtained only when the Fe — F-O compound, the heteroatom-doped carbon material, and the carbon nanotube are contained together.
It can be known from comparison of example 1 and comparative example 4 that the type of the solvent in step (2) affects the electrochemical performance of the material, and the solvent such as glycerol selected by the invention has certain viscosity, so that the effect of uniformly dispersing the particles can be realized, and simultaneously, the solvent can be carbonized to generate amorphous carbon in the heat treatment process, so that uniform coating is realized, and the function of bonding the particles is achieved. After glycerol is replaced by deionized water, the circulation stability and rate capability of the obtained electrode material are reduced because amorphous carbon cannot be provided.
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.

Claims (10)

1. The coated composite material is characterized by comprising an electrode material core and a coating layer coated on the surface of the electrode material core, wherein the coating layer comprises an Fe-F-O compound, a heteroatom doped carbon material, a carbon nanotube compound and an amorphous carbon material.
2. The clad composite material according to claim 1, wherein the electrode material core is a positive electrode material core or a negative electrode material core, preferably a positive electrode material core;
preferably, the core of the cathode material is of a disordered cubic rock salt structure;
preferably, the chemical formula of the cathode material core with the disordered cubic rock salt structure is Li1+xM1-xO2-yFyWherein x is more than or equal to 0.1 and less than or equal to 0.3, y is more than 0 and less than or equal to 0.3, and M is a transition metal element;
preferably, the transition metal element is any one or a combination of at least two of Mn, Ni, V, Mo, Fe, Ti, Zr, Cr, Co, Cu, Zn, Nb, Sc, or Y, preferably any one or a combination of at least two of Mn, Ni, V, Mo, Fe, or Ti.
3. The clad composite of claim 1 or 2Characterized in that the Fe-F-O composition is FeFxAt least one of (1) and FeyOzWherein x is not less than 2 and not more than 3, y is more than 0 and not more than 3, and z is not less than 1 and not more than 4;
preferably, the Fe-F-O compound is FeFxAnd FeyOzThe formed composition, wherein x is more than or equal to 2 and less than or equal to 3, y is more than or equal to 2 and less than or equal to 3, and z is more than or equal to 3 and less than or equal to 4;
preferably, the Fe-F-O composition is FeF2、FeF3、Fe2O3And Fe3O4The resulting composition;
preferably, the heteroatom-doped carbon material is a boron, nitrogen, sulfur and phosphorus co-doped carbon material;
preferably, the atomic ratio of boron, nitrogen, sulfur and phosphorus in the boron, nitrogen, sulfur and phosphorus co-doped carbon material is (0.5-1): (1-2): (0.5-1);
preferably, the carbon nanotubes are single-walled carbon nanotubes and/or multi-walled carbon nanotubes, preferably multi-walled carbon nanotubes;
preferably, the aspect ratio of the carbon nanotube is 500-.
4. The coated composite material as claimed in any one of claims 1 to 3, wherein the particle size of the electrode material core is 100-2000nm, preferably 300-1000 nm;
preferably, the particle size of the Fe-F-O compound is 20-100 nm;
preferably, the content of the electrode material inner core is 82-98.4%, preferably 90-97%, based on 100% of the mass of the coated composite material;
preferably, the content of the Fe-F-O compound is 0.5-5%, preferably 1-3%, based on 100% by mass of the coated composite material;
preferably, the content of the heteroatom doped carbon material is 0.5-4%, preferably 1-3%, based on 100% by mass of the coated composite material;
preferably, the content of the carbon nano tube is 0.5-5%, preferably 0.5-2% by mass of the coated composite material as 100%;
preferably, the content of the amorphous carbon material is 0.1 to 4%, preferably 0.5 to 2%, based on 100% by mass of the coated composite material;
preferably, the FeF is 100% of the Fe-F-O composition by massxThe content of (A) is 70-90%;
preferably, the coating layer is coated on part of or the whole surface of the electrode material core.
5. A method for the preparation of the clad composite material according to any one of claims 1 to 4, comprising the steps of:
(1) mixing an electrode material inner core, an Fe-F-O compound, a heteroatom doped carbon material, a carbon nano tube and an organic solution to obtain a mixed solution;
(2) and (2) drying the mixed solution obtained in the step (1) and then carrying out heat treatment to obtain the coated composite material.
6. The method according to claim 5, wherein the heteroatom-doped carbon material of step (1) is prepared by:
uniformly mixing boric acid, a nitrogen source, a sulfur source, a phosphorus source and a carbon source, and transferring the mixture into a closed container, wherein protective gas is filled in the closed container; carrying out heat treatment on the closed container in the atmosphere of protective gas, and cooling to obtain the heteroatom doped carbon material;
preferably, the nitrogen source is melamine and/or nitrilotriacetic acid;
preferably, the sulfur source is any one or a combination of at least two of sodium sulfide, sodium thiosulfate, thiourea, thiol, thiophenol, thioether, disulfide, polysulfide or cyclic sulfide;
preferably, the phosphorus source is any one or a combination of at least two of phosphonitrile trimer chloride, adenosine triphosphate, adenosine diphosphate, phosphoenone pyruvic acid, phosphate ester, tetrakis hydroxymethyl phosphonium chloride, dimethyl vinylphosphate, hexachlorocyclotriphosphazene, polydichlorophosphazene, polyalkoxyphosphazene, polyaryloxy phosphazene or polyfluorinated epoxy phosphazene;
preferably, the carbon source is any one of polyvinylpyrrolidone, poly (4-vinylpyridine) or polyethylene terephthalate or a combination of at least two of the two;
preferably, in the method for preparing the heteroatom-doped carbon material, the gas in the protective atmosphere comprises any one or a combination of at least two of nitrogen, argon or helium;
preferably, in the preparation method of the heteroatom-doped carbon material, the temperature of the heat treatment is 350-500 ℃;
preferably, in the preparation method of the heteroatom doped carbon material, the heat treatment is carried out for 1-4 h;
preferably, in the preparation method of the heteroatom-doped carbon material, the heating rate of the heat treatment is 2-10 ℃/min.
7. The production method according to claim 5 or 6, wherein the mixing in step (1) is performed in the following manner: dispersing an electrode material inner core, an Fe-F-O compound, a heteroatom doped carbon material and a carbon nano tube in an organic solution, and uniformly dispersing by ultrasonic;
preferably, the organic solution is any one of or a combination of at least two of ethylene glycol, glycerol or phenolic resin;
preferably, the power of the ultrasonic wave is 150-.
8. The production method according to any one of claims 5 to 7, wherein the drying in step (2) is spray drying;
preferably, the outlet temperature of the spray drying is 100-250 ℃;
preferably, the heat treatment of step (2) is performed under a protective atmosphere;
preferably, the gas in the protective atmosphere in the step (2) is any one or a combination of at least two of nitrogen, argon or helium;
preferably, the temperature of the heat treatment in the step (2) is 300-600 ℃;
preferably, the heating rate of the heat treatment in the step (2) is 1-10 ℃/min;
preferably, the heat treatment in the step (2) has the holding time of 0.5-6h, preferably 1-4 h.
9. The method according to any one of claims 5 to 8, characterized in that it comprises the following steps:
(1) uniformly mixing boric acid, a nitrogen source, a sulfur source, a phosphorus source and a carbon source, and transferring the mixture into a closed container to make up for the fact that the container is filled with protective gas; carrying out heat treatment on the closed container at the temperature of 350-500 ℃ for 1-4h, wherein the heating rate of the heat treatment is 2-10 ℃/min, and cooling to obtain the heteroatom doped carbon material;
(2) dispersing an electrode material inner core, an Fe-F-O compound, a heteroatom doped carbon material and a carbon nano tube in an organic solution, and performing ultrasonic dispersion uniformly to obtain a mixed solution;
(3) and (3) spray-drying the mixed solution in the step (2) at the temperature of 100-250 ℃, then carrying out heat treatment in a protective atmosphere, heating to the temperature of 300-600 ℃ at the heating rate of 1-10 ℃/min for heat treatment for 0.5-6h, and cooling to obtain the coating composite material.
10. A lithium ion battery comprising the coated composite material according to any one of claims 1 to 4.
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