CN117902571A - Graphite negative electrode material and preparation method and application thereof - Google Patents
Graphite negative electrode material and preparation method and application thereof Download PDFInfo
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- CN117902571A CN117902571A CN202211242259.8A CN202211242259A CN117902571A CN 117902571 A CN117902571 A CN 117902571A CN 202211242259 A CN202211242259 A CN 202211242259A CN 117902571 A CN117902571 A CN 117902571A
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 68
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 66
- 239000010439 graphite Substances 0.000 title claims abstract description 66
- 238000002360 preparation method Methods 0.000 title claims abstract description 25
- 239000007773 negative electrode material Substances 0.000 title description 6
- 239000010405 anode material Substances 0.000 claims abstract description 49
- 239000000463 material Substances 0.000 claims abstract description 45
- 239000002245 particle Substances 0.000 claims abstract description 34
- 238000005469 granulation Methods 0.000 claims abstract description 33
- 230000003179 granulation Effects 0.000 claims abstract description 33
- 239000011163 secondary particle Substances 0.000 claims abstract description 33
- 239000007921 spray Substances 0.000 claims abstract description 29
- 238000007493 shaping process Methods 0.000 claims abstract description 24
- 239000002270 dispersing agent Substances 0.000 claims abstract description 17
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 15
- 239000002994 raw material Substances 0.000 claims abstract description 15
- 239000011230 binding agent Substances 0.000 claims abstract description 14
- 150000001720 carbohydrates Chemical class 0.000 claims abstract description 14
- 238000003763 carbonization Methods 0.000 claims abstract description 11
- 238000005087 graphitization Methods 0.000 claims abstract description 8
- 238000002156 mixing Methods 0.000 claims abstract description 8
- 239000002904 solvent Substances 0.000 claims abstract description 7
- 239000000126 substance Substances 0.000 claims abstract description 4
- 239000011329 calcined coke Substances 0.000 claims description 34
- 239000010426 asphalt Substances 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 21
- 229920002472 Starch Polymers 0.000 claims description 16
- 229940100486 rice starch Drugs 0.000 claims description 15
- 239000008107 starch Substances 0.000 claims description 14
- 235000019698 starch Nutrition 0.000 claims description 14
- 239000002202 Polyethylene glycol Substances 0.000 claims description 13
- 229920001223 polyethylene glycol Polymers 0.000 claims description 13
- 239000000571 coke Substances 0.000 claims description 12
- 230000008569 process Effects 0.000 claims description 9
- 239000002006 petroleum coke Substances 0.000 claims description 8
- 229920002134 Carboxymethyl cellulose Polymers 0.000 claims description 7
- 239000007787 solid Substances 0.000 claims description 7
- 239000003381 stabilizer Substances 0.000 claims description 7
- 235000014633 carbohydrates Nutrition 0.000 claims description 6
- 239000011259 mixed solution Substances 0.000 claims description 6
- 239000011331 needle coke Substances 0.000 claims description 6
- 239000000084 colloidal system Substances 0.000 claims description 5
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 claims description 4
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 4
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 4
- 235000010948 carboxy methyl cellulose Nutrition 0.000 claims description 4
- 239000008112 carboxymethyl-cellulose Substances 0.000 claims description 4
- 238000012216 screening Methods 0.000 claims description 4
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 claims description 3
- 239000008103 glucose Substances 0.000 claims description 3
- 239000002010 green coke Substances 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 229920001592 potato starch Polymers 0.000 claims description 3
- -1 rice starch Substances 0.000 claims description 3
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 claims description 2
- QCDWFXQBSFUVSP-UHFFFAOYSA-N 2-phenoxyethanol Chemical compound OCCOC1=CC=CC=C1 QCDWFXQBSFUVSP-UHFFFAOYSA-N 0.000 claims description 2
- 229920002261 Corn starch Polymers 0.000 claims description 2
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 2
- CZMRCDWAGMRECN-UGDNZRGBSA-N Sucrose Chemical compound O[C@H]1[C@H](O)[C@@H](CO)O[C@@]1(CO)O[C@@H]1[C@H](O)[C@@H](O)[C@H](O)[C@@H](CO)O1 CZMRCDWAGMRECN-UGDNZRGBSA-N 0.000 claims description 2
- 229930006000 Sucrose Natural products 0.000 claims description 2
- WQZGKKKJIJFFOK-VFUOTHLCSA-N beta-D-glucose Chemical compound OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-VFUOTHLCSA-N 0.000 claims description 2
- 239000008120 corn starch Substances 0.000 claims description 2
- 229940099112 cornstarch Drugs 0.000 claims description 2
- 239000003822 epoxy resin Substances 0.000 claims description 2
- 239000005011 phenolic resin Substances 0.000 claims description 2
- 229920001568 phenolic resin Polymers 0.000 claims description 2
- 229920000647 polyepoxide Polymers 0.000 claims description 2
- 229940116317 potato starch Drugs 0.000 claims description 2
- 239000005720 sucrose Substances 0.000 claims description 2
- 229940100445 wheat starch Drugs 0.000 claims description 2
- 238000013508 migration Methods 0.000 abstract description 7
- 230000005012 migration Effects 0.000 abstract description 7
- 238000005516 engineering process Methods 0.000 abstract description 5
- 239000011361 granulated particle Substances 0.000 abstract description 5
- 230000000052 comparative effect Effects 0.000 description 11
- 239000000243 solution Substances 0.000 description 11
- 238000001878 scanning electron micrograph Methods 0.000 description 8
- 238000003756 stirring Methods 0.000 description 8
- 229910021383 artificial graphite Inorganic materials 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 6
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 5
- 229910052744 lithium Inorganic materials 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 238000010000 carbonizing Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000007770 graphite material Substances 0.000 description 3
- 239000012798 spherical particle Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 239000010406 cathode material Substances 0.000 description 2
- 235000013339 cereals Nutrition 0.000 description 2
- 238000005056 compaction Methods 0.000 description 2
- 238000009831 deintercalation Methods 0.000 description 2
- 238000005242 forging Methods 0.000 description 2
- 239000008187 granular material Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 238000004513 sizing Methods 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 244000017020 Ipomoea batatas Species 0.000 description 1
- 235000002678 Ipomoea batatas Nutrition 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 229910003481 amorphous carbon Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000004939 coking Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 229910021385 hard carbon Inorganic materials 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 238000009818 secondary granulation Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- 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
- C01B32/20—Graphite
- C01B32/205—Preparation
-
- 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
-
- 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
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- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Materials Engineering (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
The invention provides a graphite anode material, and a preparation method and application thereof. The preparation method comprises the following steps: and mixing the coke-like material, the dispersing agent, the saccharide, the binder and the solvent, performing spray granulation, carbonization shaping and graphitization treatment to obtain the graphite anode material. According to the invention, the carbonized sugar substances with spherical morphology are added into the raw materials for preparing graphite, and the spray granulation technology is combined, so that the granulated particles are sphericized, the increase of the particles is restrained to a certain extent, the tap density is increased, the spherical/spheroidal graphite secondary particles are obtained, the lithium ion migration path is shortened, and the quick charge performance is improved.
Description
Technical Field
The invention belongs to the technical field of lithium ion batteries, and relates to a graphite anode material, a preparation method and application thereof.
Background
The graphite as the negative electrode material of the lithium battery has the advantages of high initial efficiency, low expansion, low potential and the like, and is a main stream negative electrode material in the current industrial production of the lithium ion battery. However, as the consumer electronics and power battery fields place higher and higher demands on quick charge, it is generally desired to improve the quick charge capability at room temperature and low temperature, so that the graphite anode material must be specially designed and treated to meet the quick charge demand.
People usually adopt a particle design method to realize further improvement of quick charge performance, and common thinking is as follows: crushing a carbon material to a certain granularity, realizing secondary granulation through kneading, and finally graphitizing to obtain a graphite anode material with a secondary particle structure; this structure has a disadvantage in that it is difficult to achieve both capacity and quick-fill performance.
CN105024075A discloses a fast-charging graphite lithium ion battery cathode material and a preparation method thereof, and the artificial graphite material with a secondary particle structure is obtained after petroleum coke/asphalt coke and asphalt are mixed-kneaded-graphitized at high temperature, and the petroleum coke/asphalt coke is not the artificial graphite raw material with the highest capacity nor the artificial graphite raw material with the best fast-charging performance, so that the capacity and the fast-charging performance cannot be simultaneously achieved.
CN108328614a discloses a graphite cathode material for a quick-charging lithium ion battery and a preparation method thereof, wherein the composite graphite material with a secondary particle structure is obtained after the carbon material and asphalt are mixed-kneaded-carbonized-graphitized at high temperature, and the surface of particles is highly ordered after graphitized, so that the quick-charging performance is negatively affected.
CN109748587a discloses a high-capacity quick-charging graphite negative electrode material and a preparation method thereof, wherein an artificial graphite material with a secondary particle structure is obtained after the easy graphitization coke/high crystallinity graphite and the difficult graphitization coke/hard carbon are mixed-combined-crushed-high-temperature graphitization treatment, and then modified cladding is carried out, because the easy graphitization coke is not the artificial graphite raw material with the highest capacity, and the appearance of the obtained secondary particles is not spherical particles.
The common problem in the above documents is that the raw materials are not optimized, the secondary particles are not spherical, the similar spherical particles are not achieved, and when the aggregate granularity is smaller, the compaction of graphitized products is lower, so that the coating of the pole pieces can be influenced. The spherical particles theoretically have smaller OI values, the lithium ion migration path is shorter, and the quick charge performance is relatively better. The common process is to carry out sphericizing treatment on natural graphite, the yield is lower, the granularity is larger, and the secondary particles are difficult to form into spheres in the common process.
Therefore, how to improve the quick charge performance of the graphite anode material is a technical problem to be solved.
Disclosure of Invention
The invention aims to provide a graphite anode material, and a preparation method and application thereof. According to the invention, the carbonized sugar substances with spherical morphology are added into the raw materials for preparing graphite, and the spray granulation technology is combined, so that the granulated particles are sphericized, the increase of the particles is prevented, the tap density is increased, the spherical/spheroidal graphite secondary particles are obtained, the lithium ion migration path is shortened, and the quick charge performance is improved.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
In a first aspect, the present invention provides a method for preparing a spheroidal graphite anode material, the method comprising the steps of:
and mixing the coke-like material, the dispersing agent, the saccharide, the binder and the solvent, performing spray granulation, carbonization shaping and graphitization treatment to obtain the graphite anode material.
In the present invention, the solvent is not particularly limited, and the present invention is applicable to solvents which do not affect the subsequent production process of the material, such as water.
According to the invention, the carbonized sugar material with the spherical morphology is added into the raw material for preparing the artificial graphite, and the spray granulation technology is combined, so that the granulated particles are sphericized, the increase of the particles is prevented, the tap density is increased, the spherical/spheroidal graphite secondary particles are obtained, the lithium ion migration path is shortened, and the quick charge performance is improved.
In the invention, the saccharide has slight viscosity, can play a slight bonding role in the spraying process so as to facilitate the shaping of the secondary particles, ensure the spherical morphology after spraying granulation, inhibit the increase of the particles to a certain extent, and improve the tap density of the material, and if other granulation modes are selected, such as stirring granulation and the like, the spherical morphology of the secondary particles cannot be realized; the addition of the dispersing agent can effectively separate defocusing materials and binders, and meanwhile, a proper amount of binders are added, so that the cohesiveness is ensured, and meanwhile, the oversized particles caused by excessive adhesion are avoided.
That is, the method of the invention is not indispensable for raw materials and spray granulation, and the raw materials and the granulation method cooperate to obtain the spherical/spheroidic graphite anode material, prevent the particle from increasing, shorten the lithium ion migration path and realize the improvement of the quick charge performance.
Preferably, the mass ratio of the focal material to the dispersant is 1 (0.01-0.03), such as 1:0.01, 1:0.013, 1:0.015, 1:0.018, 1:0.02, 1:0.023, 1:0.025, 1:0.028, or 1:0.03, etc.
Preferably, the mass ratio of the coke-like material to the saccharide is 1 (0.04-0.1), such as 1:0.04, 1:0.05, 1:0.06, 1:0.07, 1:0.08, 1:0.09, or 1:0.1, etc.
In the invention, the mass ratio of the coke-like material to the saccharide is too small, so that the effective molding of the secondary particles cannot be realized, and the gram capacity is reduced due to the too large mass ratio.
Preferably, the mass ratio of the focal material to the binder is 1 (0.1-0.5), such as 1:0.1、1:0.13、1:0.15、1:0.18、1:0.2、1:0.23、1:0.25、1:0.28、1:0.3、1:0.33、1:0.35、1:0.38、1:0.4、1:0.43、1:0.45、1:0.48 or 1:0.5.
In the invention, the too small mass ratio of the coke-shaped material to the binder can influence the adhesion of the coke powder and the molding of the secondary particles, and the too large mass ratio can cause excessive adhesion so as to cause the particle size of the secondary particles to be too large.
Preferably, the method comprises any one or a combination of at least two of petroleum coke green coke, petroleum coke calcined coke, needle Jiao Shengjiao, needle Jiao Duan back coke, petroleum coke semi-calcined coke or needle coke semi-calcined coke, and preferably needle Jiao Duan back coke.
In the invention, needle coke calcined coke is selected, so that the energy density of the material can be ensured.
Preferably, the focal material is crushed and shaped.
Preferably, the D50 of the crushed particles is 5.5-7 μm, D100.ltoreq.21.0. Mu.m, for example, the D50 may be 5.5 μm, 6 μm, 6.5 μm or 7 μm, etc., and the D100 may be 21 μm, 20 μm, 18 μm, 15 μm, etc.
Preferably, the shaped particles have a D50 of 6.5 to 7.5 μm and a D100 of 21.0. Mu.m, for example, the D50 may be 6.5. Mu.m, 6.6. Mu.m, 6.7. Mu.m, 6.8. Mu.m, 6.9. Mu.m, 7.1. Mu.m, 7.2. Mu.m, 7.3. Mu.m, 7.4. Mu.m, 7.5. Mu.m, etc., and the D100 may be 21. Mu.m, 20. Mu.m, 18. Mu.m, 15. Mu.m, etc.
In the invention, the too large particle size of the shaped particles can affect the quick charging performance of the secondary particles, and the too small particle size can lead to lower compaction and affect the processability and gram capacity.
Preferably, the dispersing agent comprises any one or a combination of at least two of carboxymethyl cellulose, N-methyl pyrrolidone, ethylene glycol phenyl ether, N-dimethylformamide, chloroform, isopropanol and dimethyl sulfoxide, and preferably is carboxymethyl cellulose.
Preferably, the carbohydrate substance comprises any one or a combination of at least two of glucose, sucrose or starch, preferably starch.
In the invention, starch is selected, and the interlayer spacing of the amorphous carbon layer formed after carbonization of the starch is larger, which is more beneficial to the deintercalation of lithium ions.
Preferably, the starch comprises any one or a combination of at least two of corn starch, potato starch, rice starch, wheat starch, preferably rice starch.
In the invention, the grain size of the graphitized rice starch is smaller, so that the increase of secondary grains can be well inhibited.
Preferably, the binder comprises any one or a combination of at least two of asphalt, phenolic resin or epoxy resin, preferably asphalt.
Preferably, the bitumen has a softening point of 150 to 200 ℃, for example 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃ or the like.
In the present invention, too low softening point of asphalt may cause too low coking value, poor cohesiveness, insufficient granulating strength and poor effect, while too high softening point may cause too large particle size of coated particles.
Preferably, the pitch has a D50 of 4 to 7 μm, for example 4 μm, 4.3 μm, 4.5 μm, 4.8 μm, 5 μm, 5.3 μm, 5.5 μm, 5.8 μm, 6 μm, 6.3 μm, 6.5 μm, 6.8 μm or 7 μm, etc.
Preferably, the mixed raw materials further comprise a colloidal stabilizer, preferably polyethylene glycol.
In the invention, the addition of the colloid stabilizer promotes the dispersion of the dispersing agent, the scorched material and the asphalt, ensures the stability of the viscosity of the solution, can adjust the viscosity of the solution, ensures the stability of a colloid system, is convenient for feeding, and can also be used as a carbon source in the later period of polyethylene glycol.
Preferably, the mass ratio of the focal material to the colloidal stabilizer is 1 (0.05-0.3), such as 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.25, or 1:0.3, etc.
Preferably, the mixed solution has a solids content of 10 to 45%, for example 10%, 13%, 15%, 18%, 20%, 23%, 25%, 28%, 30%, 33%, 35%, 38%, 40%, 43% or 45%, etc.
Preferably, the rotational speed during the spray granulation is 380-500 Hz, such as 380Hz, 390Hz, 400Hz, 410Hz, 420Hz, 430Hz, 440Hz, 450Hz, 460Hz, 470Hz, 480Hz, 490Hz or 500Hz, etc.
In the invention, in the spray granulation process, the rotating speed is too low, the drying rate of materials is influenced, the granulation effect is influenced, the granularity is larger, and the rotating speed is too high, so that the materials are thrown to the wall, and the yield and the morphology are influenced.
Preferably, in the spray granulation process, the feeding speed is 50-80 mL/min, such as 50mL/min, 55mL/min, 60mL/min, 65mL/min, 70mL/min, 75mL/min or 80mL/min, etc.
Preferably, the temperature of the carbonization shaping is not less than 800 ℃, for example 800 ℃, 850 ℃, 900 ℃, 950 ℃, 1000 ℃, 1050 ℃, 1100 ℃, 1150 ℃, 1200 ℃ or the like.
Preferably, the carbonized and shaped material is subjected to depolymerization and screening.
According to the invention, the particle size of the carbonized and shaped material is reduced and the tap density is improved by depolymerizing the carbonized and shaped material.
As a preferred technical scheme, the preparation method comprises the following steps:
Crushing and shaping needle Jiao Duan post-coke, wherein the D50 of the shaped calcined coke is 6.5-7.5 mu m, mixing the shaped calcined coke, a dispersing agent, rice starch, asphalt with a softening point of 150-200 ℃, polyethylene glycol and a solvent to obtain a mixed solution with a solid content of 10-45%, carrying out spray granulation on the mixed solution at a feeding speed of 50-80 mL/min and a rotating speed of 380-500 Hz, carrying out carbonization shaping at a temperature of more than or equal to 800 ℃, depolymerizing and screening, and graphitizing to obtain the graphite anode material;
Wherein the mass ratio of the calcined coke after shaping to the dispersant is 1 (0.01-0.03); the mass ratio of the calcined coke after shaping to the starch is 1 (0.04-0.1); the mass ratio of the shaped calcined coke to the asphalt is 1 (0.1-0.5), and the mass ratio of the shaped calcined coke to the colloid stabilizer is 1 (0.05-0.3).
In a second aspect, the invention provides a graphite anode material, which is prepared by the preparation method of the graphite anode material in the first aspect, wherein the graphite anode material is spherical secondary particles and/or spheroid secondary particles.
Preferably, the specific surface area of the spheroidal graphite anode material is 1.5-3 m 2/g, such as 1.5m2/g、1.6m2/g、1.7m2/g、1.8m2/g、1.9m2/g、2m2/g、2.1m2/g、2.2m2/g、2.3m2/g、2.4m2/g、2.5m2/g、2.6m2/g、2.7m2/g、2.8m2/g、2.9m2/g or 3m 2/g, etc.
Preferably, the D50 of the graphite anode material is 20 to 30 μm, for example 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm or 30 μm, etc.
Preferably, the graphite anode material has a tap density of 0.5 to 0.7g/cm 3, for example 0.5g/cm 3、0.6g/cm3 or 0.7g/cm 3, etc.
In a third aspect, the present invention also provides a lithium ion battery comprising a graphite anode material according to the first aspect.
Compared with the prior art, the invention has the following beneficial effects:
According to the invention, the carbohydrate and the dispersing agent with spherical morphology after carbonization are added into the raw materials for preparing the graphite, and the spray granulation technology is combined, so that the carbohydrate can play a slight bonding role in the spray process to facilitate shaping of secondary particles, meanwhile, the spherical morphology after spray granulation is ensured, particle enlargement is prevented, the granulated particles are sphericized, the addition of the dispersing agent can effectively disperse the coke-like material and the binding agent, asphalt is selected as the binding agent, the caking property is ensured, meanwhile, excessive bonding is avoided, the particles are excessively large, finally, the spheroidal graphite secondary particles are obtained, the tap density of the material is improved by depolymerization, the lithium ion migration path is shortened, and the quick charging performance is improved while the normal exertion of the gram capacity of the material is maintained. When the graphite anode material provided by the invention is adopted in a battery, the charging capacity ratio at 2C/0.1C can reach more than 98.31%, and no lithium precipitation phenomenon occurs at 3C.
Drawings
Fig. 1 is an SEM image of the shaped calcined coke particles of step (1) provided in example 1.
Fig. 2 is an SEM image of the spray granulated material in example 1.
Fig. 3 is an SEM image of the carbonized shaped material provided in example 1.
Fig. 4 is an SEM image of the graphite anode material provided in example 1.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.
Example 1
The embodiment provides a graphite anode material which is a spheroid secondary particle.
The preparation method of the graphite anode material comprises the following steps:
(1) Coarse crushing the calcined coke (needle coke after forging) to obtain particles with D50 of 7 mu m (D100 is less than 21 mu m), and shaping to obtain particles with D50 of 7.3 mu m (D100 is less than 21 mu m);
(2) Dissolving 0.046Kg of carboxymethyl cellulose (CMC) in water, adding 0.4Kg of rice starch, stirring to obtain milky colloidal solution, adding 2Kg of shaped calcined coke, 0.5Kg of asphalt (with a softening point of 150 ℃ C., D50 of 5 mu m) and 0.2Kg of polyethylene glycol (PEG), mixing, stirring to obtain colloidal solution with a solid content of 23%, feeding the colloidal solution at a feeding speed of 60mL/min, adjusting the rotating speed of a centrifugal atomizing disc in spray granulation to 500Hz (a heating fan of 35HZ, an induced air fan of 30HZ, and a heating power supply with an inlet temperature of 200 ℃ C., an outlet temperature of 90 ℃ C.) for spray granulation to obtain a material;
(3) And (3) carbonizing and shaping the obtained material at 1100 ℃, depolymerizing, and graphitizing to obtain the graphite anode material.
Fig. 1 shows an SEM image of needle-shaped Jiao Duan post-coke particles shaped in step (1) provided in example 1, fig. 2 shows an SEM image of spray-granulated material in example 1, fig. 3 shows an SEM image of carbonized shaped material provided in example 1, fig. 4 shows an SEM image of graphite negative electrode material provided in example 1, and it can be seen from fig. 1 to fig. 4 that calcined coke is in a sheet shape, secondary particles are in a spherical structure after spray granulation, a balling effect is good, and the particle size of the secondary particles is relatively uniform.
Example 2
The embodiment provides a graphite anode material which is a spheroid secondary particle.
The preparation method of the graphite anode material comprises the following steps:
(1) Coarse crushing the calcined coke (needle Jiao Duan back coke), crushing the calcined coke to obtain particles with D50 of 6.8 mu m (D100 is less than 21 mu m), and shaping the particles to obtain particles with D50 of 7 mu m (D100 is less than 21 mu m);
(2) Dissolving 0.017Kg of carboxymethyl cellulose (CMC) in water, adding 0.068Kg of rice starch, stirring to obtain milky colloidal solution, adding 1.7Kg of shaped calcined coke, 0.2Kg of asphalt (with a softening point of 180 ℃ and a D50 of 4 mu m) and 0.085Kg of polyethylene glycol (PEG), mixing, stirring to obtain colloidal solution with a solid content of 10%, feeding the colloidal solution at a feeding speed of 50mL/min, adjusting the rotating speed of a centrifugal atomizing disk in spray granulation to 380Hz (a heating fan 35HZ, a induced air fan 30HZ, and a heating power supply for carrying out spray granulation when the inlet temperature reaches 200 ℃ and the outlet temperature reaches 90 ℃ to obtain a material;
(3) And (3) carbonizing and shaping the obtained material at 850 ℃, depolymerizing, and graphitizing to obtain the graphite anode material.
Example 3
The embodiment provides a graphite anode material which is a spheroid secondary particle.
The preparation method of the graphite anode material comprises the following steps:
(1) Coarse crushing the calcined coke (needle coke after forging) to obtain particles with D50 of 6.5 μm (D100 < 21 μm), and shaping to obtain particles with D50 of 6.7 μm (D100 < 21 μm);
(2) Dissolving 0.0515Kg of carboxymethyl cellulose (CMC) in water, adding 0.17Kg of rice starch, stirring to obtain milky colloidal solution, adding 1.7Kg of shaped calcined coke, 0.85Kg of asphalt (with a softening point of 150 ℃ and D50 of 7 mu m) and 0.51g of polyethylene glycol (PEG), mixing, stirring to obtain colloidal solution with a solid content of 35%, feeding the colloidal solution at a feeding speed of 80mL/min, adjusting the rotating speed of a centrifugal atomizing disc in spray granulation to 500Hz (a heating fan of 35HZ, an induced air fan of 30HZ, and a heating power supply for inlet temperature of 200 ℃ and outlet temperature of 90 ℃) for spray granulation to obtain a material;
(3) And (3) carbonizing and shaping the obtained material at 900 ℃, depolymerizing, and graphitizing to obtain the graphite anode material.
Example 4
The difference between this example and example 1 is that the starch in step (2) of this example is sweet potato starch.
The remaining preparation methods and parameters were consistent with example 1.
Example 5
The difference between this example and example 1 is that no PEG was added in step (2) of this example.
The remaining preparation methods and parameters were consistent with example 1.
Example 6
The difference between this example and example 1 is that the calcined coke in step (1) of this example is replaced with green coke (needle coke).
The remaining preparation methods and parameters were consistent with example 1.
Example 7
The difference between this example and example 1 is that the mass ratio of calcined coke to rice starch after shaping in step (2) of this example is 1:0.12.
The remaining preparation methods and parameters were consistent with example 1.
Example 8
The difference between this example and example 1 is that the mass ratio of calcined coke to rice starch after shaping in step (2) of this example is 1:0.03.
The remaining preparation methods and parameters were consistent with example 1.
Example 9
The difference between this example and example 1 is that the graphitization treatment was directly performed without depolymerization after the carbonization and sizing in step (3) of this example.
The remaining preparation methods and parameters were consistent with example 1.
Example 10
This example differs from example 1 in that this example replaces the rice starch in step (1) with glucose.
The remaining preparation methods and parameters were consistent with example 1.
Comparative example 1
The difference between this comparative example and example 1 is that no rice starch was added in step (2) of this comparative example.
The remaining preparation methods and parameters were consistent with example 1.
Comparative example 2
The difference between this comparative example and example 1 is that stirring agglomeration granulation was used in step (2) of this comparative example.
The remaining preparation methods and parameters were consistent with example 1.
The D50 and tap density of the materials provided in examples 1 to 10 and comparative examples 1 to 2, which were not graphitized, were measured, and the results are shown in Table 1.
The graphite anode materials provided in examples 1-10 and comparative examples 1-2 were prepared to obtain anode sheets, and then prepared to obtain batteries.
Table 1 shows the D50, tap density, and gram capacity of the cells for the materials provided in examples 1-10 and comparative examples 1-2 that were not graphitized.
TABLE 1
Electrochemical performance tests are carried out on the batteries provided in the examples 1-3, 10 and the comparative examples 1-2, the 3C lithium precipitation test condition is that 0.1C constant current is charged to 2V, the batteries are left to stand, then 3C constant current is discharged for a period of time, and the lithium precipitation condition is observed after the batteries are left to stand for a period of time; the 2C/0.1C test conditions were 0.1C constant current charge, standing, and then 2C constant current discharge, the results of which are shown in Table 2.
TABLE 2
The data in tables 1 and 2 are combined to show that:
From the data obtained in examples 1 and 4, rice starch was selected to promote better spherical secondary particles.
From the data of examples 1 and 5, it is evident that the absence of PEG in the raw material affects the uniformity of the slurry, resulting in poor granulation.
From the data obtained in example 1 and example 6, it was found that it was difficult to achieve high energy density by selecting raw coke.
From the data of examples 1 and 7 and 8, it is evident that too small a mass ratio of calcined coke to starch does not allow for efficient formation of secondary particles, while too large a mass ratio results in a decrease in gram volume.
From the data of example 1 and example 9, it is clear that the secondary particles were too large in particle size without depolymerization after carbonization and sizing.
From the data in examples 1 and 10, it is clear that the starch is selected for the saccharide, so that the deintercalation of lithium ions can be better realized, and the quick charge performance can be better improved.
From the data of example 1 and comparative examples 1-2, it is evident that starch and spray granulation are indispensable, i.e., the raw materials and the method act synergistically to prepare secondary particles having a spherical structure, thereby improving the quick-charging performance of the material on the basis of ensuring gram capacity.
In summary, the carbohydrate and the dispersing agent which are carbonized and have spherical morphology are added into the raw materials for preparing the graphite, and meanwhile, the spray granulation technology is combined, so that the carbohydrate can play a slight bonding role in the spray process, the shaping of secondary particles is facilitated, meanwhile, the spherical morphology after spray granulation is ensured, the particle enlargement is prevented, the granulated particles are sphericized, the addition of the dispersing agent can effectively disperse the coke-like material and the binding agent, asphalt is used as the binding agent, the caking property is ensured, meanwhile, the particle oversize caused by excessive bonding is avoided, finally, the spherical-like graphite secondary particles are obtained, the tap density of the material is improved by depolymerization, the lithium ion migration path is shortened, the normal play of the gram capacity of the material is maintained, and meanwhile, the quick charging performance is improved. When the graphite anode material provided by the invention is adopted in a battery, the charging capacity ratio at 2C/0.1C can reach more than 98.31%, and no lithium precipitation phenomenon occurs at 3C.
The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.
Claims (10)
1. The preparation method of the graphite anode material is characterized by comprising the following steps of:
and mixing the coke-like material, the dispersing agent, the saccharide, the binder and the solvent, performing spray granulation, carbonization shaping and graphitization treatment to obtain the graphite anode material.
2. The method for preparing a graphite anode material according to claim 1, wherein the mass ratio of the coke-like material to the dispersant is 1 (0.01-0.03);
preferably, the mass ratio of the coke-like material to the saccharide is 1 (0.04-0.1);
preferably, the mass ratio of the coke-like material to the binder is 1 (0.1-0.5).
3. The method for preparing a graphite anode material according to claim 1 or 2, wherein the coke-like material comprises any one or a combination of at least two of petroleum coke green coke, petroleum coke calcined coke, needle Jiao Shengjiao, needle Jiao Duan calcined coke, petroleum coke semi-calcined coke or needle coke semi-calcined coke, preferably needle Jiao Duan calcined coke;
preferably, the focal material is crushed and shaped;
Preferably, the D50 of the crushed particles is 5.5-7 mu m, and D100 is less than or equal to 21.0 mu m;
Preferably, the D50 of the shaped particles is 6.5-7.5 mu m, and D100 is less than or equal to 21.0 mu m;
Preferably, the dispersing agent comprises any one or a combination of at least two of carboxymethyl cellulose, N-methyl pyrrolidone, ethylene glycol phenyl ether, N-dimethylformamide, chloroform, isopropanol and dimethyl sulfoxide, and preferably is carboxymethyl cellulose;
Preferably, the carbohydrate substance comprises any one or a combination of at least two of glucose, sucrose or starch, preferably starch;
Preferably, the starch comprises any one or a combination of at least two of corn starch, potato starch, rice starch and wheat starch, preferably rice starch;
Preferably, the binder comprises any one or a combination of at least two of asphalt, phenolic resin or epoxy resin, preferably asphalt;
Preferably, the softening point of the asphalt is 150-200 ℃;
Preferably, the pitch has a D50 of 4 to 7. Mu.m.
4. A method of preparing a graphite anode material according to any one of claims 1-3, wherein the mixed raw materials further comprise a colloidal stabilizer, preferably polyethylene glycol;
Preferably, the mass ratio of the coke-like material to the colloid stabilizer is 1 (0.05-0.3).
5. The method for producing a graphite anode material according to any one of claims 1 to 4, wherein the solid content of the mixed solution is 10 to 45%.
6. The method for preparing a graphite anode material according to any one of claims 1 to 5, wherein the rotational speed in the spray granulation process is 380 to 500Hz;
Preferably, in the spray granulation process, the feeding speed is 50-80 mL/min;
preferably, the temperature of the carbonization shaping is more than or equal to 800 ℃;
Preferably, the carbonized and shaped material is subjected to depolymerization and screening.
7. The method for producing a graphite anode material according to any one of claims 1 to 6, characterized in that the method comprises the steps of:
Crushing and shaping needle Jiao Duan post-coke, wherein the D50 of the shaped calcined coke is 6.5-7.5 mu m, mixing the shaped calcined coke, a dispersing agent, rice starch, asphalt with a softening point of 150-200 ℃, polyethylene glycol and a solvent to obtain a mixed solution with a solid content of 10-45%, carrying out spray granulation on the mixed solution at a feeding speed of 50-80 mL/min and a rotating speed of 380-500 Hz, carrying out carbonization shaping at a temperature of more than or equal to 800 ℃, depolymerizing and screening, and graphitizing to obtain the graphite anode material;
Wherein the mass ratio of the calcined coke after shaping to the dispersant is 1 (0.01-0.03); the mass ratio of the calcined coke after shaping to the starch is 1 (0.04-0.1); the mass ratio of the shaped calcined coke to the asphalt is 1 (0.1-0.5), and the mass ratio of the shaped calcined coke to the colloid stabilizer is 1 (0.05-0.3).
8. A graphite anode material, characterized in that the graphite anode material is prepared by the preparation method of the graphite anode material according to any one of claims 1 to 7, and the graphite anode material is spherical secondary particles and/or spheroid secondary particles.
9. The graphite anode material according to claim 8, wherein the specific surface area of the graphite anode material is 1.5-3 m 2/g;
preferably, the D50 of the graphite anode material is 20-30 mu m;
Preferably, the tap density of the graphite anode material is 0.5-0.7 g/cm 3.
10. A lithium ion battery comprising the graphite anode material of claim 8 or 9.
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