CN112645300B - Hard carbon negative electrode material, lithium ion battery, and preparation method and application of hard carbon negative electrode material - Google Patents

Hard carbon negative electrode material, lithium ion battery, and preparation method and application of hard carbon negative electrode material Download PDF

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CN112645300B
CN112645300B CN201911081369.9A CN201911081369A CN112645300B CN 112645300 B CN112645300 B CN 112645300B CN 201911081369 A CN201911081369 A CN 201911081369A CN 112645300 B CN112645300 B CN 112645300B
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hard carbon
source precursor
carbon source
negative electrode
precursor powder
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CN112645300A (en
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曾繁俊
李政杰
夏圣安
沈龙
张秀云
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Huawei Technologies Co Ltd
Shanghai Shanshan Technology Co Ltd
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Shanghai Shanshan Technology Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
    • 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
    • H01M4/36—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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention discloses a hard carbon negative electrode material, a lithium ion battery, and a preparation method and application thereof. The preparation method comprises the following steps: step (1), performing cross-linking reaction on carbon source precursor powder and an additive to prepare a modified carbon source precursor; the additive comprises a cross-linking agent, a modifier and a dispersing auxiliary agent; step (2), sequentially carrying out heat treatment, cooling and mixing with a lithium-rich agent on the modified carbon source precursor to obtain a modified hard carbon precursor; and (3) carbonizing the modified hard carbon precursor in vacuum to obtain the hard carbon cathode material. The hard carbon negative electrode material prepared by the invention belongs to typical amorphous carbon, has high pyrolysis yield, and the lithium ion battery prepared by using the hard carbon negative electrode material as a negative electrode material has high first reversible capacity, high first coulombic efficiency, stable property and good batch consistency.

Description

Hard carbon negative electrode material, lithium ion battery and preparation method and application thereof
Technical Field
The invention relates to a hard carbon negative electrode material, a lithium ion battery, and a preparation method and application thereof.
Background
At present, carbon materials are widely applied as negative electrode materials, wherein natural graphite and artificial graphite are mainly used; however, since the theoretical capacity of graphite is low, generally about 372mah/g, and the compatibility of the conventional graphite negative electrode material with electrolyte is poor, co-intercalation of solvent ions is easily generated during charging and discharging to destroy the structure, so that the cycle stability and the coulombic efficiency of the graphite negative electrode material are affected, especially the rate capability of the graphite negative electrode is reduced, and the continuous large-current discharge capacity required by a large-scale power battery cannot be met. Compared with graphite, hard carbon has isotropic structural characteristics, amorphous microstructure and large interlayer spacing, is beneficial to rapid diffusion of lithium ions, has excellent cycle performance, rate capability and safety, and is paid attention again in the aspect of power lithium ion batteries.
Hard carbon refers to carbon which is still difficult to graphitize at 2500 ℃ and is pyrolytic carbon of high molecular polymers; at present, carbon source precursors for preparing hard carbon mainly comprise thermoplastic high molecular materials, biomass and the like. The biomass has the advantages of wide source, low price and the like, but the properties of the prepared hard carbon negative electrode material are unstable due to the instability of the properties of the biomass, and the hard carbon negative electrode material prepared by the biomass has the defects of high ash content, low carbon residue rate, low yield and the like. The thermoplastic polymer material not only has wide source and relatively low price, but also has the advantages of stable property, capability of automatically manufacturing samples with different specifications, high pyrolysis yield and the like, which cannot be achieved by biomass materials.
The hard carbon has a special carbon layer structure with short-range order and long-range disorder, so that the lithium ions can enter and exit more conveniently, and the hard carbon cathode material has high theoretical specific capacity and excellent rate capability; however, the hard carbon negative electrode material has the defects of low reversible capacity, low first coulombic efficiency and the like.
Therefore, how to develop the hard carbon anode material with stable carbon source precursor source, high reversible capacity and high first coulombic efficiency has important research significance and application value.
Disclosure of Invention
The invention aims to overcome the defects that a hard carbon negative electrode material in the prior art is low in reversible capacity, low in first coulombic efficiency and the like, and provides a hard carbon negative electrode material, a lithium ion battery, and a preparation method and application thereof. The hard carbon negative electrode material belongs to typical amorphous carbon, has high pyrolysis yield, and the lithium ion battery prepared by using the hard carbon negative electrode material as the negative electrode material has high first reversible capacity, high first coulombic efficiency, stable property and good batch consistency.
The invention solves the technical problems through the following technical scheme.
The invention provides a preparation method of a hard carbon negative electrode material, which comprises the following steps:
step (1), performing cross-linking reaction on carbon source precursor powder and an additive to prepare a modified carbon source precursor; the additive comprises a cross-linking agent, a modifier and a dispersing aid;
step (2), sequentially carrying out heat treatment, cooling and mixing with a lithium-rich agent on the modified carbon source precursor to prepare a modified hard carbon precursor;
and (3) carbonizing the modified hard carbon precursor in vacuum to obtain the hard carbon cathode material.
In the step (1), the carbon source precursor powder has a median particle diameter D 50 It may be 3-15 μm, preferably 5 μm. The maximum particle diameter D of the carbon source precursor powder max And may be less than 70 μm.
In the step (1), the carbon source precursor powder can be prepared by crushing and grading a raw material carbon source precursor.
Wherein, the crushing and classifying treatment can be conventional in the field, and preferably is airflow crushing and classifying and/or mechanical crushing and classifying.
The raw material carbon source precursor can be a thermoplastic polymer material containing carbon elements, hydrogen elements, oxygen elements and the like, which is conventional in the art, preferably one or more of coal pitch, petroleum pitch and modified coumarone resin, and more preferably petroleum pitch.
The softening point of the raw carbon source precursor is preferably more than 200 ℃, more preferably more than 250 ℃.
Wherein the modified coumarone resin can be a type 3# resin produced by Baoshan Steel works Ltd.
The content of carbon element in the thermoplastic polymer material is preferably 80 to 90wt%.
The content of hydrogen in the thermoplastic polymer material is preferably 3 to 15wt%.
The content of the oxygen element in the thermoplastic polymer material is preferably 0 to 5wt%, but not 0.
In step (1), the cross-linking agent may be one or more cross-linking agents conventionally used in the art, preferably one or more of hydrogen peroxide, nitric acid, ammonium nitrate, ammonium persulfate, performic acid, benzoyl peroxide and cyclohexanone peroxide, and more preferably "a mixture of hydrogen peroxide and nitric acid" and/or "a mixture of hydrogen peroxide and performic acid", for example, "a mixture of 30% by mass of hydrogen peroxide and 20% by mass of nitric acid" or "a mixture of 30% by mass of hydrogen peroxide and performic acid".
Wherein, the concentration of the hydrogen peroxide can be 15-40wt%, preferably 30wt%.
The nitric acid is preferably added as an aqueous nitric acid solution. The concentration of the aqueous nitric acid solution may be 10 to 30wt%, preferably 20wt%.
In the step (1), the mass ratio of each crosslinking agent to the carbon source precursor powder may be from 5 to 100, preferably from 10 to 50, for example, from 20.
When the crosslinking agent is a mixture of 30% by mass of hydrogen peroxide and 20% by mass of nitric acid, the mass ratio of the 30% by mass of hydrogen peroxide to the carbon source precursor powder can be 35.
When the crosslinking agent is a mixture of 30% by mass of hydrogen peroxide and performic acid, the mass ratio of the 30% by mass of hydrogen peroxide to the carbon source precursor powder may be 35.
In step (1), the modifier may be one or more of boron element, phosphorus element and nitrogen element, preferably one or more of phosphoric acid, phosphorus pentoxide, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, urea, ammonia water, melamine, boric acid, boron oxide and boron nitride, more preferably one or more of "a mixture of boric acid and melamine", "a mixture of phosphoric acid and urea" and "a mixture of phosphoric acid and melamine", for example, "a mixture of phosphoric acid and urea with a mass fraction of 80%" or "a mixture of phosphoric acid and melamine with a mass fraction of 80%".
The phosphoric acid is preferably added in the form of an aqueous phosphoric acid solution. The concentration of the phosphoric acid aqueous solution may be 80wt%.
In the step (1), the mass ratio of the modifier to the carbon source precursor powder may be 5-40, preferably 20-38, for example, 25.
When the modifier is a mixture of boric acid and melamine, the mass ratio of the boric acid to the carbon source precursor powder may be 10.
When the modifier is a mixture of 80% phosphoric acid and urea by mass, the mass ratio of 80% phosphoric acid to the carbon source precursor powder can be 15.
When the modifier is a mixture of 80% by mass of phosphoric acid and melamine, the mass ratio of the 80% by mass of phosphoric acid to the carbon source precursor powder may be 18.
In the step (1), the dispersing auxiliary agent may be a surfactant with an HLB value of 10 to 18, preferably one or more of cetyltrimethylammonium bromide, polyoxyethylene monostearate, nonylphenol polyoxyethylene ether, tween 20, and tween 80.
In the step (1), the mass ratio of the dispersing aid to the carbon source precursor powder may be 0.5 to 5, preferably 2.
Preferably, in the step (1), before the crosslinking reaction, the carbon source precursor powder and the additive are mixed uniformly.
More preferably, in step (1), water is added before the mixing operation. The mass ratio of the carbon source precursor powder to the water may be 30-60, preferably 45.
Wherein the water may be deionized water.
In step (1), the crosslinking reaction is preferably carried out under an inert atmosphere.
Wherein the inert atmosphere may be conventional in the art, preferably one or more of nitrogen, helium and argon.
In step (1), the temperature of the crosslinking reaction may be conventional in the art, and is preferably 100 to 180 ℃, more preferably 150 to 180 ℃.
In step (1), the time for the crosslinking reaction may be conventional in the art, and is preferably 4 to 18 hours, and more preferably 4 to 8 hours.
In the step (2), the heat treatment is preferably performed under an inert atmosphere.
Wherein the inert atmosphere may be conventional in the art, preferably one or more of nitrogen, helium and argon.
In step (2), the temperature of the heat treatment may be conventional in the art, and is preferably 500 to 800 ℃, more preferably 550 to 650 ℃, for example 600 ℃.
In step (2), the heat treatment time may be conventional in the art, and is preferably 1 to 3 hours, and more preferably 1 to 2 hours.
In step (2) of a preferred embodiment, the heat treatment is carried out in the following manner: heating to 550-650 deg.C at a rate of 2-5 deg.C/min, and maintaining for 1-2h, preferably heating to 600 deg.C at a rate of 3 deg.C/min, and maintaining for 1h.
In the step (2), the content of volatile components in the material prepared by the heat treatment can be 3-8%.
In step (2), the cooling operation may be conventional in the art. Preferably, the temperature is reduced to 10-80 ℃, more preferably to room temperature.
In step (2), the lithium-rich agent may be a lithium-containing compound conventionally used in the art, preferably one or more of lithium acetate, lithium citrate, lithium hydroxide, lithium nitrate and lithium chloride.
In the step (2), the mass ratio of the lithium-rich agent to the carbon source precursor powder may be from 0.5 to 20, preferably from 1 to 5.
In step (2), a solvent is preferably added before the mixing operation. The solvent may be water or an organic solvent.
Wherein the water may be deionized water. The organic solvent may be one or more of an alcohol solvent, an ether solvent and a ketone solvent, and preferably an alcohol solvent.
Wherein, the mass ratio of the material prepared by cooling to the solvent added in the mixing process in the step (2) can be 30-60, preferably 45.
In the step (3), the vacuum carbonization treatment is preferably performed by drying treatment.
Wherein, the temperature of the drying treatment can be 80-120 ℃, preferably 100 ℃.
Wherein, the drying time can be 4-10h, preferably 8h.
In step (3), the vacuum carbonization operation may be conventional in the art, and is preferably performed in a vacuum furnace.
In the step (3), the vacuum degree of the vacuum carbonization can be 1-1000Pa, preferably 1-10Pa.
In step (3), the temperature of the vacuum carbonization may be conventional in the art, and is preferably 900 to 1150 ℃, and more preferably 1000 to 1050 ℃.
In step (3), the vacuum carbonization time can be conventional in the art, and is preferably 2 to 10 hours, and more preferably 4 to 6 hours.
In step (3) of a preferred embodiment, the vacuum carbonization is performed in the following manner: heating to 1000-1050 deg.C at a rate of 1-5 deg.C/min, and maintaining for 4-6h, preferably at a rate of 2 deg.C/min to 1000-1050 deg.C, and maintaining for 4-6h.
In the step (3), after the vacuum carbonization, the treatment of temperature reduction, crushing and screening is further included.
The operation of cooling can be conventional in the art, and preferably cooling to room temperature.
The comminution operation may be conventional in the art, preferably by jet or mechanical comminution.
The mesh number of the screen for the sieving treatment may be 80 mesh or more, preferably 300 mesh.
In the present invention, the room temperature may be 10-40 ℃ which is conventionally considered in the art.
The invention also provides the hard carbon cathode material prepared by the preparation method.
The median particle diameter D of the hard carbon negative electrode material 50 It may be 5 to 15 μm, preferably 8 to 12 μm, for example 9 μm or 10 μm.
The hard carbon negative electrode material has a true density of 1.9-2.1g/cm 3 Preferably 2 to 2.08g/cm 3 For example, 2.02g/cm 3 Or 2.05g/cm 3 。
The tap density of the hard carbon negative electrode material can be 0.6-0.8g/cm 3 Preferably 0.78-0.85g/cm 3 For example, 0.82g/cm 3 。
The hard carbon negative electrode material has a specific surface area of 2-6m 2 A/g, preferably 3 to 4.6m 2 In terms of/g, e.g. 3.5m 2 G or 4.0m 2 /g。
The content of oxygen element in the hard carbon negative electrode material can be 3-10%, and the total content of the miscellaneous elements can be 1-5%, wherein the miscellaneous elements comprise one or more of boron element, phosphorus element and nitrogen element.
The hard carbon anode material may have a D002 interlayer spacing of 3.733 to 3.797nm.
The invention also provides application of the hard carbon negative electrode material as a negative electrode material in a lithium ion battery.
The invention also discloses a lithium ion battery, and the cathode material of the lithium ion battery is the hard carbon cathode material.
In the present invention, the lithium ion battery may be prepared by a conventional method in the art.
On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.
The reagents and starting materials used in the present invention are commercially available.
The positive progress effects of the invention are as follows: according to the invention, the carbon source precursor powder is subjected to surface-to-inside gradient crosslinking and molecular structure doping, so that the structural property of the carbon source precursor is improved, the pyrolysis yield is improved, the obtained hard carbon cathode material has the characteristics of stable three-dimensional structure, larger D002 interlamellar spacing, high compaction density and rich pores, and also has excellent electrochemical performance, the first reversible capacity is more than 480mAh/g, and the first coulombic efficiency is more than 85%. The preparation method of the hard carbon cathode material also has the advantages of wide raw material source, low production cost, short process flow and easy operation, and the prepared hard carbon cathode product has stable property and good batch consistency and is easy to realize industrialization.
Drawings
Fig. 1 is an SEM image of a hard carbon anode material prepared in example 2;
fig. 2 is an XRD pattern of the hard carbon negative electrode material prepared in example 2;
FIG. 3 is a graph showing the first charge and discharge curves of a lithium ion half cell fabricated using the hard carbon anode material fabricated in example 2 as an anode material;
fig. 4 is a first delithiation capacity test chart of lithium ion half-cells prepared by using different batches of hard carbon anode materials prepared in example 2 as anode materials.
Detailed Description
The invention is further illustrated by the following examples, which are not intended to limit the invention thereto. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.
The coal pitch used in the following examples and comparative examples was modified coal pitch produced by saddle steel corporation; the petroleum asphalt is high-temperature petroleum asphalt produced by Dalian reinforcement materials GmbH; the Malong resin is model No. 3 resin produced by Baoshan Steel works Ltd.
Example 1
Step (1), adopting a jet milling classifier to prepare petroleum asphalt with the softening point of 250 ℃ into a median particle diameter D 50 Carbon source precursor powder of 5 μm; dispersing the prepared carbon source precursor powder in deionized water under the condition of stirring, wherein the mass ratio of the carbon source precursor powder to the deionized water is 45:100, mixing carbon source precursor powder with 30 mass percent of hydrogen peroxide, 20 mass percent of nitric acid, boric acid, melamine and tween 20 according to the mass ratio of 100; and then carrying out crosslinking reaction for 8 hours at the temperature of 150 ℃ to prepare a modified carbon source precursor.
Step (2), carrying out heat treatment on the modified carbon source precursor under the protection of nitrogen, heating to 550 ℃ at a heating rate of 3 ℃/min, preserving heat for 2h, and cooling to room temperature after heat preservation; the content of volatile components in the material after heat treatment is 8%. Under the condition of stirring, dispersing the material prepared after cooling in deionized water, wherein the mass ratio of the material prepared after cooling to the deionized water is 45; and mixing with lithium hydroxide, wherein the mass ratio of the lithium hydroxide to the carbon source precursor is 1.
Step (3), drying the modified hard carbon precursor for 8 hours at the temperature of 100 ℃; and transferring the mixture into a vacuum furnace, adjusting the vacuum degree of the vacuum furnace to be within 10Pa, heating to 1050 ℃ at the heating rate of 2 ℃/min, carrying out vacuum carbonization for 4h at 1050 ℃, cooling to room temperature, carrying out jet milling, and sieving by a 300-mesh standard sieve to obtain the hard carbon negative electrode material.
Example 2
Step (1), adopting a jet milling classifier to prepare petroleum asphalt with the softening point of 280 ℃ into a median particle diameter D 50 Carbon source precursor powder of 5 μm; dispersing the prepared carbon source precursor powder in water under the condition of stirring, wherein the mass ratio of the carbon source precursor powder to the water is 45; and then carrying out crosslinking reaction for 4h at 180 ℃ to obtain the modified carbon source precursor.
Step (2), carrying out heat treatment on the modified carbon source precursor under the protection of nitrogen, heating to 600 ℃ at a heating rate of 3 ℃/min, preserving heat for 1h, and cooling to room temperature after heat preservation; the content of volatile components in the material after heat treatment was 6%. Under the condition of stirring, dispersing the material prepared after cooling in water, wherein the mass ratio of the material prepared after cooling to the water is 45; and mixing with lithium chloride, wherein the mass ratio of the lithium chloride to the carbon source precursor is 3.
Step (3), drying the modified hard carbon precursor for 8 hours at the temperature of 100 ℃; and transferring the mixture into a vacuum furnace, adjusting the vacuum degree of the vacuum furnace to be within 10Pa, heating to 1000 ℃ at the heating rate of 2 ℃/min, carrying out vacuum carbonization for 6 hours at the temperature of 1000 ℃, cooling to room temperature, carrying out jet milling, and sieving by a 300-mesh standard sieve to obtain the hard carbon cathode material.
Example 3
Step (1), preparing coal tar pitch with the softening point of 250 ℃ into a median particle diameter D by adopting a jet milling classifier 50 Carbon source precursor powder of 5 μm; dispersing the prepared carbon source precursor powder in water under the condition of stirring, wherein the mass ratio of the carbon source precursor powder to the water is 45; and then carrying out crosslinking reaction for 4h at 180 ℃ to obtain the modified carbon source precursor.
Step (2), carrying out heat treatment on the modified carbon source precursor under the protection of nitrogen, heating to 600 ℃ at a heating rate of 3 ℃/min, preserving heat for 1h, and cooling to room temperature after heat preservation is finished; the content of volatile components in the material after heat treatment was 6%. Under the condition of stirring, dispersing the material prepared after cooling in water, wherein the mass ratio of the material prepared after cooling to the water is 45; and mixing with lithium acetate, wherein the mass ratio of the lithium acetate to the carbon source precursor is 5.
Step (3), drying the modified hard carbon precursor for 8 hours at the temperature of 100 ℃; and then transferring the mixture into a vacuum furnace, adjusting the vacuum degree of the vacuum furnace to be within 10Pa, heating to 1000 ℃ at the heating rate of 2 ℃/min, carrying out vacuum carbonization for 6h at the temperature of 1000 ℃, cooling to room temperature, carrying out jet milling, and sieving by a 300-mesh standard sieve to obtain the hard carbon negative electrode material.
Example 4
Step (1), preparing coal pitch with a softening point of 280 ℃ into a median particle diameter D by adopting a jet milling classifier 50 Carbon source precursor powder of 5 μm; dispersing the prepared carbon source precursor powder in water under the stirring condition, wherein the mass ratio of the carbon source precursor powder to the water is 45; and then carrying out crosslinking reaction for 8h at the temperature of 150 ℃ to prepare a modified carbon source precursor.
Step (2), heating the modified carbon source precursor to 550 ℃ at a heating rate of 3 ℃/min under the protection of nitrogen, preserving heat for 2h, and cooling to room temperature after heat preservation; the content of volatile components in the material after heat treatment is 8%. Under the condition of stirring, dispersing the material prepared after cooling in water, wherein the mass ratio of the material prepared after cooling to the water is 45; and mixing with lithium citrate, wherein the mass ratio of the lithium citrate to the carbon source precursor is 1.
Step (3), drying the modified hard carbon precursor for 8 hours at the temperature of 100 ℃; and transferring the mixture into a vacuum furnace, adjusting the vacuum degree of the vacuum furnace to be within 10Pa, heating to 1050 ℃ at the heating rate of 2 ℃/min, carrying out vacuum carbonization for 4h at 1050 ℃, cooling to room temperature, carrying out jet milling, and sieving by a 300-mesh standard sieve to obtain the hard carbon negative electrode material.
Example 5
Step (1), preparing the modified coumarone resin with the softening point of 250 ℃ into a median particle diameter D by adopting a jet milling classifier 50 Is carbon source precursor powder of 5 mu m; dispersing the prepared carbon source precursor powder in water under the stirring condition, wherein the mass ratio of the carbon source precursor powder to the water is 45; and then carrying out crosslinking reaction for 4h at 180 ℃ to obtain the modified carbon source precursor.
Step (2), carrying out heat treatment on the modified carbon source precursor under the protection of nitrogen, heating to 650 ℃ at a heating rate of 3 ℃/min, preserving heat for 1h, and cooling to room temperature after heat preservation; the content of volatile components in the heat-treated material was 4%. Under the condition of stirring, dispersing the material prepared after cooling in water, wherein the mass ratio of the material prepared after cooling to the water is 45; and mixing with lithium nitrate, wherein the mass ratio of the lithium nitrate to the carbon source precursor is 1.
Step (3), drying the modified hard carbon precursor for 8 hours at the temperature of 100 ℃; and transferring the mixture into a vacuum furnace, adjusting the vacuum degree of the vacuum furnace to be within 10Pa, heating to 1050 ℃ at the heating rate of 2 ℃/min, carrying out vacuum carbonization for 4 hours at 1050 ℃, cooling to room temperature, carrying out jet milling, and sieving by a 300-mesh standard sieve to obtain the hard carbon cathode material.
Comparative example 1
Step (1), adopting a jet milling classifier to prepare petroleum asphalt with the softening point of 250 ℃ into a median particle diameter D 50 Is carbon source precursor powder of 5 mu m; dispersing the prepared carbon source precursor powder in water under the condition of stirring, wherein the mass ratio of the carbon source precursor powder to the water is 45; and then carrying out crosslinking reaction for 8 hours at the temperature of 150 ℃ to prepare a modified carbon source precursor.
Step (2), carrying out heat treatment on the modified carbon source precursor under the protection of nitrogen, heating to 550 ℃ at a heating rate of 3 ℃/min, preserving heat for 2 hours, and cooling to room temperature after heat preservation is finished to prepare a modified hard carbon precursor; the content of volatile components in the material after heat treatment is 8%.
Step (3), drying the modified hard carbon precursor for 8 hours at the temperature of 100 ℃; and transferring the mixture into a vacuum furnace, adjusting the vacuum degree of the vacuum furnace to be within 10Pa, heating to 1050 ℃ at the heating rate of 2 ℃/min, carrying out vacuum carbonization for 4 hours at 1050 ℃, cooling to room temperature, carrying out jet milling, and sieving by a 300-mesh standard sieve to obtain the hard carbon cathode material.
Comparative example 2
Step (1), preparing coal tar pitch with the softening point of 250 ℃ into a median particle diameter D by adopting a jet milling classifier 50 Carbon source precursor powder of 5 μm; under the condition of stirring, the prepared carbon sourceDispersing the precursor powder in water, wherein the mass ratio of the carbon source precursor powder to the water is 45; and then carrying out crosslinking reaction for 4h at 180 ℃ to obtain the modified carbon source precursor.
Step (2), carrying out heat treatment on the modified carbon source precursor under the protection of nitrogen, heating to 600 ℃ at a heating rate of 3 ℃/min, preserving heat for 1h, and cooling to room temperature after heat preservation is finished to prepare a modified hard carbon precursor; the content of volatile components in the material after heat treatment was 6%.
Step (3), drying the modified hard carbon precursor for 8 hours at the temperature of 100 ℃; and transferring the mixture into a vacuum furnace, adjusting the vacuum degree of the vacuum furnace to be within 10Pa, heating to 1000 ℃ at the heating rate of 2 ℃/min, carrying out vacuum carbonization for 6 hours at the temperature of 1000 ℃, cooling to room temperature, carrying out jet milling, and sieving by a 300-mesh standard sieve to obtain the hard carbon cathode material.
Comparative example 3
Step (1), preparing the modified coumarone resin with the softening point of 250 ℃ into a median particle diameter D by adopting a jet milling classifier 50 Carbon source precursor powder of 5 μm; dispersing the prepared carbon source precursor powder in water under the condition of stirring, wherein the mass ratio of the carbon source precursor powder to the water is 45; and then carrying out crosslinking reaction for 4h at 180 ℃ to obtain the modified carbon source precursor.
Step (2), carrying out heat treatment on the modified carbon source precursor under the protection of nitrogen, heating to 650 ℃ at a heating rate of 3 ℃/min, preserving heat for 1h, and cooling to room temperature after heat preservation is finished to prepare a modified hard carbon precursor; the content of volatile components in the heat-treated material was 4%.
Step (3), drying the modified hard carbon precursor for 8 hours at the temperature of 100 ℃; and transferring the mixture into a vacuum furnace, adjusting the vacuum degree of the vacuum furnace to be within 10Pa, heating to 1050 ℃ at the heating rate of 2 ℃/min, carrying out vacuum carbonization for 4 hours at 1050 ℃, cooling to room temperature, carrying out jet milling, and sieving by a 300-mesh standard sieve to obtain the hard carbon cathode material.
Comparative example 4
Step (1), preparing the modified coumarone resin with the softening point of 250 ℃ into a median particle diameter D by adopting a jet milling classifier 50 Is carbon source precursor powder of 5 mu m; dispersing the prepared carbon source precursor powder in water under the stirring condition, wherein the mass ratio of the carbon source precursor powder to the water is 45; and then carrying out crosslinking reaction for 4h at 180 ℃ to obtain the modified carbon source precursor.
Step (2), carrying out heat treatment on the modified carbon source precursor under the protection of nitrogen, heating to 650 ℃ at a heating rate of 3 ℃/min, preserving heat for 1h, and cooling to room temperature after heat preservation; the content of volatile components in the material after heat treatment is 4%. Under the condition of stirring, dispersing the material prepared after cooling in water, wherein the mass ratio of the material prepared after cooling to the water is 45; and mixing with lithium nitrate, wherein the mass ratio of the lithium nitrate to the carbon source precursor is 1.
Step (3), drying the modified hard carbon precursor for 8 hours at the temperature of 100 ℃; and transferring the mixture into a vacuum furnace, adjusting the vacuum degree of the vacuum furnace to be within 10Pa, heating to 1050 ℃ at the heating rate of 2 ℃/min, carrying out vacuum carbonization for 4h at 1050 ℃, cooling to room temperature, carrying out jet milling, and sieving by a 300-mesh standard sieve to obtain the hard carbon negative electrode material.
Comparative example 5
Step (1), adopting a jet milling classifier to prepare petroleum asphalt with the softening point of 250 ℃ into a median particle diameter D 50 Carbon source precursor powder of 5 μm; dispersing the prepared carbon source precursor powder in deionized water under the condition of stirring, wherein the mass ratio of the carbon source precursor powder to the deionized water is 45; thenAnd carrying out crosslinking reaction for 8h at 150 ℃ to prepare a modified carbon source precursor.
Step (2), carrying out heat treatment on the modified carbon source precursor under the protection of nitrogen, heating to 550 ℃ at a heating rate of 3 ℃/min, preserving heat for 2h, and cooling to room temperature after heat preservation; the content of volatile components in the material after heat treatment is 8%. Under the condition of stirring, dispersing the material prepared after cooling in deionized water, wherein the mass ratio of the material prepared after cooling to the deionized water is 45; and mixing with lithium hydroxide, wherein the mass ratio of the lithium hydroxide to the carbon source precursor is 1.
Step (3), drying the modified hard carbon precursor for 8 hours at the temperature of 100 ℃; and then transferring the mixture into a tubular furnace, wherein the atmosphere condition is nitrogen, heating to 1050 ℃ at the heating rate of 2 ℃/min, carbonizing for 4 hours at 1050 ℃, cooling to room temperature, carrying out jet milling, and sieving by a 300-mesh standard sieve to obtain the hard carbon negative electrode material.
Comparative example 6
Carrying out water washing flotation on 100g of rice hulls for 10min to remove dust and other solid particles, draining, and then conveying to a vacuum drying oven to dry at 105 ℃; carrying out heat treatment on the cleaned and dried carbon-containing raw material under the inert atmosphere of nitrogen, wherein the temperature of the heat treatment is 800 ℃ and the time is 2h; after cooling, the material after heat treatment is crushed by a ball mill to obtain crushed material with the particle size D50 of 15 mu m; carrying out ultrasonic acid washing on the crushed material for 1 hour by adopting 100mL of hydrochloric acid with the concentration of 10wt%, then washing the material subjected to ultrasonic acid washing with water until the pH value of a washing liquid is neutral, and drying at 105 ℃ to obtain a hard carbon precursor; adding 25g of hard carbon precursor into 66g of lithium acetate with the concentration of 10wt% and stirring, then gradually adding 26g of ammonium fluoride with the concentration of 10wt%, mixing and stirring, and performing centrifugal separation and drying to obtain a solid pre-lithiated hard carbon precursor with the surface coated with a lithium-containing substance; mixing the pre-lithiated hard carbon precursor with asphalt with the quinoline insoluble content of 0.05wt% and the softening point of 258 ℃ according to the mass ratio of 95:5, adding the mixture into a reaction kettle with a double-helical ribbon stirring paddle for coating, wherein the coating treatment temperature is 280 ℃, and the coating treatment time is 2 hours; and (3) carbonizing the coated pre-lithiated hard carbon precursor at 900 ℃ for 2 hours in an inert atmosphere of nitrogen, cooling to room temperature, crushing, sieving (D50 is 15 mu m), and demagnetizing to obtain the hard carbon negative electrode material.
Effect example 1
The hard carbon negative electrode materials of examples 1 to 5 and comparative examples 1 to 5 were respectively subjected to particle size, true density, tap density, specific surface area, powder compaction density, pyrolysis yield, and D002 layer spacing test, and the results are shown in table 1; the surface morphology of the hard carbon negative electrode material prepared in example 2 was tested, and the results are shown in fig. 1; the hard carbon anode material prepared in example 2 was subjected to an X-ray diffraction test, and the result is shown in fig. 2.
The name, model and test method of the instrument used for the test are as follows: the particle size is obtained by testing with a Malvern laser particle size analyzer MS2000 by a laser method; the real density is obtained by adopting an American Congta UltraPYC 1200e type full-automatic real density analyzer through a real density liquid analysis method; the tap density is obtained by adopting a tap density tester FZS4-4B through a tapping method; the specific surface area is obtained by adopting a specific surface area determinator NOVA2000e of the American Congta through a nitrogen adsorption method; the compacted density of the powder adopts an electronic pressure tester UTM7305; the surface morphology was measured using an electron microscope model QUANTA200, manufactured by FEI of the Netherlands; x-ray diffraction an X-ray diffractometer manufactured by Bruker AXS with model number D8-ADVANCE was used. The pyrolysis yield is the mass percentage of the hard carbon cathode material of the final product and the precursor powder of the raw material carbon source. The D002 test method is obtained by calculating data tested by an X-ray diffractometer with the model of D8-ADVANCE according to the Sheble formula.
The first charge and discharge performance test was performed on the prepared half cells using the hard carbon negative electrode materials prepared in examples 1 to 5 and comparative examples 1 to 5 as negative electrode materials by the half cell test method, and the results are shown in table 1.
The testing method of the half cell comprises the following steps: preparing a polyvinylidene fluoride solution with the mass fraction of 6-7% by taking N-methyl pyrrolidone as a solvent, uniformly mixing a hard carbon negative electrode material, polyvinylidene fluoride and conductive carbon black according to the mass ratio of 85 to 3, coating the mixture on a copper foil, and putting the coated pole piece into a vacuum drying oven at the temperature of 90 ℃Drying under vacuum for 4h for later use. Then assembled into 2430 type button cells in an argon-filled German Michelona glove box with 1mol/L LiPF 6 The three-component mixed solvent is characterized in that a mixed solution of EC: DMC: EMC =1 (volume ratio) is used as an electrolyte, a metal lithium sheet is used as a counter electrode, electrochemical performance tests are carried out on the assembled half-cell on a U.S. Arbin electrochemical detection system, the charging and discharging voltage range is 0mV to 2.0V, and the first lithium intercalation capacity, the first lithium deintercalation capacity and the corresponding first coulomb efficiency are tested at 0.1C. The resulting half-cell performance parameters are shown in table 1. The hard carbon negative electrode material prepared in example 2 was subjected to X-ray diffraction test, and the results are shown in fig. 2, and it can be seen from the X-ray diffraction test that the hard carbon negative electrode material prepared in the present invention is a typical amorphous carbon. The initial charge-discharge curve of the lithium ion half cell prepared by using the hard carbon negative electrode material prepared in example 2 as the negative electrode material is shown in fig. 3, and the lithium ion half cell can be judged to be typical amorphous carbon according to the charge-discharge curve of fig. 3, and the initial coulombic efficiency of the lithium ion half cell is high. The first lithium removal capacity test of the lithium ion half-cell using different batches of hard carbon negative electrode materials prepared in example 2 as negative electrode materials is shown in fig. 4, and it can be seen from fig. 4 that the hard carbon negative electrode materials prepared by the preparation method of the present invention have good batch consistency.
TABLE 1
Figure BDA0002264071780000151
Figure BDA0002264071780000161
By combining the characterization data and the electrical property data of the hard carbon anode material powder prepared in the examples 1-5 and the comparative examples 1-5, it can be known that the specification of the selected carbon source precursor, the type of the reaction additive, the modifier and the like have great influence on the performance of the final hard carbon anode material. As can be seen from Table 1, in example 1, the hard carbon anode material prepared from petroleum asphalt with a high softening point is prepared into a lithium ion half-cell, and the first reversible capacity at 0.1C is tested497mAh/g, the first coulombic efficiency of 86 percent and the powder compaction density of 1.15g/cm 3 . Example 3 the hard carbon negative electrode material was made into a lithium ion half cell using high softening point coal pitch as the raw material and varying the type of the cross-linking agent and the modifier, and the first reversible capacity was 518mAh/g, the first coulombic efficiency was 85.4%, and the powder compaction density was 1.1g/cm 3 . Example 5 the modified coumarone resin is used as a raw material, the prepared hard carbon cathode material is prepared into a lithium ion half-cell, the first reversible capacity is tested to reach 481mAh/g, the first coulombic efficiency is 85.3%, and the powder compaction density is 1.2g/cm 3 . The D002 interlamellar spacing of the hard carbon cathode material prepared by the method is about 0.37nm, and the hard carbon cathode material prepared by the method can be further judged to be amorphous carbon.
In contrast, the hard carbon negative electrode materials prepared in comparative examples 1 to 5 are used as negative electrodes, and the first coulombic efficiency of the prepared lithium ion half-cell is far lower than that of the hard carbon negative electrode materials prepared in examples 1 to 5, which shows that the modification process provided by the invention can effectively compensate lithium ions consumed by the obtained hard carbon negative electrode materials in the first charge-discharge process, so that the hard carbon negative electrode materials with high first coulombic efficiency are obtained. Compared with the traditional graphite cathode, the hard carbon cathode material of the lithium ion battery has higher capacity characteristic and wide application prospect in the field of high-energy density power batteries.
Comparative example 4 no dispersing aid was added in step (1), and most of the material was coked after heat treatment in step (2) to produce coke. The lithium ion battery prepared by taking the hard carbon cathode material prepared in the comparative example 4 as the cathode has relatively poor electrochemical performance and does not have the basic characteristics of hard carbon; the first lithium intercalation capacity and the first lithium deintercalation capacity are respectively 325mAh/g and 217mAh/g; the first coulombic efficiency was 66.7%, and the XRD result and the D002 interlayer spacing result showed no obvious amorphous state; hard carbon is difficult to generate; therefore, the effective dispersing auxiliary agent can be combined with other process parameters to effectively prepare the hard carbon cathode material with high pyrolysis yield, and the lithium ion battery prepared by using the hard carbon cathode material as the cathode material has the advantages of high first reversible capacity, high first coulombic efficiency, stable property and good batch consistency.
Comparative example 5 differs from example 1 only in that non-vacuum carbonization is employed in step (3) instead of vacuum carbonization in example 1. As can be seen from the data in Table 1, the lithium ion battery prepared by using the hard carbon negative electrode material prepared by non-vacuum carbonization and combining with other technical characteristics of the invention as the negative electrode has the first charging capacity of 531.8mAh/g, the first lithium removal capacity of 426mAh/g and the first coulombic efficiency of 80.1 percent, which are poorer than the performance of the hard carbon negative electrode material prepared in example 1.
Comparative example 6 is a hard carbon negative electrode material prepared by using biomass as a carbon source precursor by using the existing preparation process. By adopting the half-cell testing method, the first delithiation capacity of the lithium ion battery prepared by taking the hard carbon negative electrode material as the negative electrode is 396mAh/g, and the first coulombic efficiency is 76 percent, which are all poorer than the performances of the hard carbon negative electrode material prepared by the invention.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims (20)

1. The preparation method of the hard carbon negative electrode material is characterized by comprising the following steps of:
step (1), performing cross-linking reaction on carbon source precursor powder and an additive to prepare a modified carbon source precursor; the additive comprises a cross-linking agent, a modifier and a dispersing aid; the mass ratio of the cross-linking agent to the carbon source precursor powder is 5-60; the mass ratio of the modifier to the carbon source precursor powder is 5-40; the mass ratio of the dispersing auxiliary agent to the carbon source precursor powder is 0.5-5;
the cross-linking agent is one or more of hydrogen peroxide, nitric acid, ammonium nitrate, ammonium persulfate, performic acid, benzoyl peroxide and cyclohexanone peroxide;
the modifier is one or more of boron element, phosphorus element and nitrogen element;
the dispersing auxiliary agent is one or more of cetyl trimethyl ammonium bromide, polyoxyethylene monostearate, nonylphenol polyoxyethylene ether, tween 20 and tween 80;
the carbon source precursor powder is prepared by crushing and grading a raw material carbon source precursor; the raw material carbon source precursor is one or more of coal pitch, petroleum pitch and modified coumarone resin;
step (2), sequentially carrying out heat treatment, cooling and mixing with a lithium-rich agent on the modified carbon source precursor to prepare a modified hard carbon precursor; the mass ratio of the lithium-rich agent to the carbon source precursor powder is 0.5-20;
the lithium-rich agent is one or more of lithium acetate, lithium citrate, lithium hydroxide, lithium nitrate and lithium chloride;
and (3) carbonizing the modified hard carbon precursor in vacuum to obtain the hard carbon cathode material.
2. The method for producing the hard carbon anode material according to claim 1, wherein in the step (1), the carbon source precursor powder has a median diameter D 50 Is 3-15 μm;
and/or in the step (1), the maximum grain diameter D of the carbon source precursor powder max Less than 70 μm;
and/or, in the step (1), the cross-linking agent is a mixture of hydrogen peroxide and nitric acid and/or a mixture of hydrogen peroxide and performic acid;
and/or in the step (1), the mass ratio of the cross-linking agent to the carbon source precursor powder is 10-50;
and/or in the step (1), the modifier is one or more of phosphoric acid, phosphorus pentoxide, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, urea, ammonia water, melamine, boric acid, boron oxide and boron nitride;
and/or in the step (1), the mass ratio of the modifier to the carbon source precursor powder is 20-38;
and/or in the step (1), the mass ratio of the dispersing auxiliary to the carbon source precursor powder is 2;
and/or in the step (1), before the crosslinking reaction, uniformly mixing the carbon source precursor powder and the additive;
and/or, in the step (1), the crosslinking reaction is carried out under the condition of inert atmosphere;
and/or, in the step (1), the temperature of the crosslinking reaction is 100-180 ℃; and/or in the step (1), the time of the crosslinking reaction is 4-18h.
3. The method for preparing the hard carbon anode material according to claim 1, wherein in the step (1), the carbon source precursor powder has a median particle diameter D 50 Is 5 μm;
and/or in the step (1), the cross-linking agent is a mixture of 30 mass percent of hydrogen peroxide and 20 mass percent of nitric acid or a mixture of 30 mass percent of hydrogen peroxide and performic acid;
and/or in the step (1), the mass ratio of the cross-linking agent to the carbon source precursor powder is 20;
and/or in the step (1), the modifier is one or more of a mixture of boric acid and melamine, a mixture of phosphoric acid and urea and a mixture of phosphoric acid and melamine;
and/or in the step (1), the mass ratio of the modifier to the carbon source precursor powder is 25;
and/or, in the step (1), the temperature of the crosslinking reaction is 150-180 ℃;
and/or in the step (1), the time of the crosslinking reaction is 4-8h.
4. The method for preparing a hard carbon anode material according to claim 1, wherein in the step (1), the modifier is "a mixture of phosphoric acid and urea with a mass fraction of 80%" or "a mixture of phosphoric acid and melamine with a mass fraction of 80%".
5. The method for producing a hard carbon anode material according to claim 2, wherein in the step (1), the pulverization classification treatment is jet pulverization classification and/or mechanical pulverization classification;
and/or, in the step (1), the softening point of the raw material carbon source precursor is more than 200 ℃;
and/or, in the step (1), the concentration of the hydrogen peroxide is 15-40wt%;
and/or, in step (1), the nitric acid is added in the form of aqueous nitric acid solution;
in the step (1), when the cross-linking agent is a mixture of 30% by mass of hydrogen peroxide and 20% by mass of nitric acid, the mass ratio of the 30% by mass of hydrogen peroxide to the carbon source precursor powder is 35;
in the step (1), when the cross-linking agent is a mixture of 30% by mass of hydrogen peroxide and performic acid, the mass ratio of the 30% by mass of hydrogen peroxide to the carbon source precursor powder is 35;
and/or, in step (1), the phosphoric acid is added in the form of an aqueous phosphoric acid solution;
in the step (1), when the modifier is a mixture of boric acid and melamine, the mass ratio of the boric acid to the carbon source precursor powder is 10;
in the step (1), when the modifier is a mixture of 80% by mass of phosphoric acid and urea, the mass ratio of 80% by mass of phosphoric acid to the carbon source precursor powder is 15;
in the step (1), when the modifier is a mixture of 80% by mass of phosphoric acid and melamine, the mass ratio of 80% by mass of phosphoric acid to the carbon source precursor powder is 18;
and/or, in step (1), adding water before the mixing operation;
and/or, in the step (1), the inert atmosphere is one or more of nitrogen, helium and argon.
6. The method for preparing a hard carbon anode material according to claim 5, wherein in the step (1), the softening point of the raw carbon source precursor is more than 250 ℃;
and/or in the step (1), the concentration of the hydrogen peroxide is 30wt%;
and/or, in the step (1), the nitric acid is added in the form of a nitric acid aqueous solution, and the concentration of the nitric acid aqueous solution is 10-30wt%;
and/or, in the step (1), the phosphoric acid is added in the form of a phosphoric acid aqueous solution, and the concentration of the phosphoric acid aqueous solution is 80wt%.
7. The method for preparing a hard carbon anode material according to claim 5, wherein the nitric acid is added in the form of an aqueous nitric acid solution having a concentration of 20wt% in the step (1).
8. The method for preparing a hard carbon anode material according to claim 5, wherein in the step (1), the content of carbon element in the raw carbon source precursor is 80-90wt%;
and/or in the step (1), the content of hydrogen element in the raw material carbon source precursor is 3-15wt%;
and/or, in the step (1), the content of oxygen element in the raw material carbon source precursor is 0-5wt%, but not 0;
and/or in the step (1), the mass ratio of the carbon source precursor powder to the water is 30-60;
and/or, in the step (1), the water is deionized water.
9. The method for preparing a hard carbon anode material according to claim 5, wherein in the step (1), the mass ratio of the carbon source precursor powder to the water is 45.
10. The method for producing a hard carbon anode material according to any one of claims 1 to 9, wherein in the step (2), the heat treatment is performed under an inert atmosphere;
and/or, in the step (2), the temperature of the heat treatment is 500-800 ℃;
and/or in the step (2), the time of the heat treatment is 1-3h;
and/or in the step (2), the content of volatile components in the material prepared by the heat treatment is 3-8%;
and/or in the step (2), the temperature is reduced to 10-80 ℃;
and/or in the step (2), the mass ratio of the lithium-rich agent to the carbon source precursor powder is 1-5;
and/or, in the step (2), adding a solvent before the mixing operation;
and/or, in the step (3), the vacuum carbonization treatment is carried out with a drying treatment;
and/or, in the step (3), the vacuum carbonization is carried out in a vacuum furnace;
and/or in the step (3), the vacuum degree of the vacuum carbonization is 1-1000Pa;
and/or, in the step (3), the temperature of the vacuum carbonization is 900-1150 ℃;
and/or in the step (3), the vacuum carbonization time is 2-10h;
and/or in the step (3), after the vacuum carbonization, further comprising the steps of cooling, crushing and screening.
11. The method for preparing a hard carbon anode material according to claim 10, wherein the temperature of the heat treatment in the step (2) is 550 to 650 ℃;
and/or in the step (2), the time of the heat treatment is 1-2h;
and/or, in the step (2), the temperature is reduced to room temperature;
and/or in the step (2), the mass ratio of the lithium-rich agent to the carbon source precursor powder is 3;
and/or, in the step (2), adding a solvent before the mixing operation, wherein the solvent is water or an organic solvent;
and/or in the step (3), the vacuum degree of the vacuum carbonization is 1-10Pa;
and/or, in the step (3), the temperature of the vacuum carbonization is 1000-1050 ℃;
and/or in the step (3), the vacuum carbonization time is 4-6h.
12. The method for preparing a hard carbon anode material according to claim 10, wherein the temperature of the heat treatment in the step (2) is 600 ℃.
13. The method for preparing a hard carbon anode material according to claim 11, wherein in the step (2), the inert atmosphere is one or more of nitrogen, helium and argon;
and/or, in the step (2), the heat treatment is carried out according to the following modes: heating to 550-650 ℃ at a heating rate of 2-5 ℃/min, and preserving heat for 1-2h;
and/or, in the step (2), the water is deionized water;
and/or in the step (2), the organic solvent is one or more of an alcohol solvent, an ether solvent and a ketone solvent;
and/or in the step (2), the mass ratio of the material prepared after the temperature reduction to the solvent added in the mixing process in the step (2) is 30-60;
and/or in the step (3), the temperature of the drying treatment is 80-120 ℃;
and/or in the step (3), the drying treatment time is 4-10h;
and/or, in the step (3), the vacuum carbonization is carried out according to the following modes: heating to 1000-1050 ℃ at a heating rate of 1-5 ℃/min, and preserving heat for 4-6h;
and/or, in the step (3), the temperature is reduced to room temperature;
and/or, in the step (3), the pulverization is airflow pulverization or mechanical pulverization;
and/or in the step (3), the mesh number of the screen subjected to screening treatment is more than 80 meshes.
14. The method for preparing a hard carbon anode material according to claim 11, wherein the heat treatment is performed in the following manner in the step (2): heating to 600 ℃ at the heating rate of 3 ℃/min, and keeping the temperature for 1h;
and/or, in the step (2), the organic solvent is an alcohol solvent;
and/or in the step (2), the mass ratio of the material prepared after cooling to the solvent added in the mixing process in the step (2) is 45;
and/or in the step (3), the temperature of the drying treatment is 100 ℃;
and/or in the step (3), the drying treatment time is 8h;
and/or, in the step (3), the vacuum carbonization is carried out according to the following modes: heating to 1000-1050 deg.C at a rate of 2 deg.C/min, and maintaining for 4-6h;
and/or in the step (3), the mesh number of the screen subjected to screening treatment is 300 meshes.
15. A hard carbon anode material, characterized in that it is produced by the method for producing a hard carbon anode material according to any one of claims 1 to 14.
16. The hard carbon anode material according to claim 15, wherein the hard carbon anode material has a median particle diameter D 50 5-15 μm;
and/or the true density of the hard carbon negative electrode material is 1.9-2.1g/cm 3 ；
And/or the tap density of the hard carbon negative electrode material is 0.6-0.8g/cm 3 ；
And/or the specific surface area of the hard carbon negative electrode material is 2-6m 2 /g；
And/or the content of oxygen element in the hard carbon negative electrode material is 3-10%, and the total content of miscellaneous elements is 1-5%; the hetero element comprises one or more of boron, phosphorus and nitrogen;
and/or the D002 interlamellar spacing of the hard carbon anode material is 3.733-3.797nm.
17. The hard carbon anode material according to claim 15, wherein the hard carbon anode material has a median particle diameter D 50 Is 8-12 μm;
and/or the true density of the hard carbon negative electrode material is 2-2.08g/cm 3 ；
And/or the tap density of the hard carbon negative electrode material is 0.78-0.85g/cm 3 ；
And/or the specific surface area of the hard carbon negative electrode material is 3-4.6m 2 /g。
18. The hard carbon anode material according to claim 15, wherein the hard carbon anode material has a median particle diameter D 50 9 μm or 10 μm;
and/or the true density of the hard carbon negative electrode material is 2.02g/cm 3 Or 2.05g/cm 3 ；
And/or the tap density of the hard carbon anode material is0.82g/cm 3 ；
And/or the specific surface area of the hard carbon anode material is 3.5m 2 G or 4.0m 2 /g。
19. Use of the hard carbon anode material according to any one of claims 15 to 18 as an anode material in a lithium ion battery.
20. A lithium ion battery, characterized in that the negative electrode material of the lithium ion battery is the hard carbon negative electrode material according to any one of claims 15 to 18.
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