CN115611275A - Artificial graphite negative electrode active material, preparation and application thereof - Google Patents
Artificial graphite negative electrode active material, preparation and application thereof Download PDFInfo
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- CN115611275A CN115611275A CN202211288777.3A CN202211288777A CN115611275A CN 115611275 A CN115611275 A CN 115611275A CN 202211288777 A CN202211288777 A CN 202211288777A CN 115611275 A CN115611275 A CN 115611275A
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- 229910021383 artificial graphite Inorganic materials 0.000 title claims abstract description 49
- 239000007773 negative electrode material Substances 0.000 title claims abstract description 28
- 238000002360 preparation method Methods 0.000 title claims abstract description 16
- 239000002994 raw material Substances 0.000 claims abstract description 56
- 239000000571 coke Substances 0.000 claims abstract description 48
- 238000000034 method Methods 0.000 claims abstract description 38
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 35
- 238000005087 graphitization Methods 0.000 claims abstract description 35
- 238000011282 treatment Methods 0.000 claims abstract description 35
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 28
- 239000002245 particle Substances 0.000 claims abstract description 26
- 238000010438 heat treatment Methods 0.000 claims abstract description 22
- 229910052723 transition metal Inorganic materials 0.000 claims abstract description 21
- 150000003624 transition metals Chemical class 0.000 claims abstract description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 17
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 16
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims abstract description 12
- 238000002156 mixing Methods 0.000 claims abstract description 9
- 238000010000 carbonizing Methods 0.000 claims abstract description 6
- 238000003825 pressing Methods 0.000 claims abstract description 6
- 238000000465 moulding Methods 0.000 claims abstract description 4
- 239000007789 gas Substances 0.000 claims description 29
- 230000008569 process Effects 0.000 claims description 26
- 239000001301 oxygen Substances 0.000 claims description 19
- 229910052760 oxygen Inorganic materials 0.000 claims description 19
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 17
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 16
- 238000003763 carbonization Methods 0.000 claims description 8
- 239000011331 needle coke Substances 0.000 claims description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims description 8
- 239000002006 petroleum coke Substances 0.000 claims description 8
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 claims description 6
- 229910001981 cobalt nitrate Inorganic materials 0.000 claims description 6
- 239000010426 asphalt Substances 0.000 claims description 5
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 claims description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical group [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 4
- 239000011261 inert gas Substances 0.000 claims description 4
- 229910021503 Cobalt(II) hydroxide Inorganic materials 0.000 claims description 3
- 239000006183 anode active material Substances 0.000 claims description 3
- 229910000428 cobalt oxide Inorganic materials 0.000 claims description 3
- ASKVAEGIVYSGNY-UHFFFAOYSA-L cobalt(ii) hydroxide Chemical compound [OH-].[OH-].[Co+2] ASKVAEGIVYSGNY-UHFFFAOYSA-L 0.000 claims description 3
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(ii) oxide Chemical compound [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 claims description 3
- 229910000480 nickel oxide Inorganic materials 0.000 claims description 3
- DOLZKNFSRCEOFV-UHFFFAOYSA-L nickel(2+);oxalate Chemical compound [Ni+2].[O-]C(=O)C([O-])=O DOLZKNFSRCEOFV-UHFFFAOYSA-L 0.000 claims description 3
- BFDHFSHZJLFAMC-UHFFFAOYSA-L nickel(ii) hydroxide Chemical compound [OH-].[OH-].[Ni+2] BFDHFSHZJLFAMC-UHFFFAOYSA-L 0.000 claims description 3
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 claims description 3
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 claims description 3
- 239000006253 pitch coke Substances 0.000 claims description 3
- USFZMSVCRYTOJT-UHFFFAOYSA-N Ammonium acetate Chemical compound N.CC(O)=O USFZMSVCRYTOJT-UHFFFAOYSA-N 0.000 claims description 2
- 239000005695 Ammonium acetate Substances 0.000 claims description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 2
- 229910002651 NO3 Inorganic materials 0.000 claims description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 2
- 229940043376 ammonium acetate Drugs 0.000 claims description 2
- 235000019257 ammonium acetate Nutrition 0.000 claims description 2
- 235000019270 ammonium chloride Nutrition 0.000 claims description 2
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 2
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 claims description 2
- 229910052921 ammonium sulfate Inorganic materials 0.000 claims description 2
- 235000011130 ammonium sulphate Nutrition 0.000 claims description 2
- 229910017052 cobalt Inorganic materials 0.000 claims description 2
- 239000010941 cobalt Substances 0.000 claims description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 2
- 238000001513 hot isostatic pressing Methods 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 239000002931 mesocarbon microbead Substances 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 150000003839 salts Chemical class 0.000 claims description 2
- 229910021384 soft carbon Inorganic materials 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 38
- 239000006182 cathode active material Substances 0.000 abstract description 8
- 239000000243 solution Substances 0.000 description 18
- 230000000052 comparative effect Effects 0.000 description 10
- 238000005265 energy consumption Methods 0.000 description 9
- 229910002804 graphite Inorganic materials 0.000 description 7
- 239000010439 graphite Substances 0.000 description 7
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- 239000011362 coarse particle Substances 0.000 description 6
- 239000002131 composite material Substances 0.000 description 6
- 239000010419 fine particle Substances 0.000 description 6
- 238000004321 preservation Methods 0.000 description 6
- 239000010406 cathode material Substances 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- MQRWBMAEBQOWAF-UHFFFAOYSA-N acetic acid;nickel Chemical compound [Ni].CC(O)=O.CC(O)=O MQRWBMAEBQOWAF-UHFFFAOYSA-N 0.000 description 4
- 239000005539 carbonized material Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229940078494 nickel acetate Drugs 0.000 description 4
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 3
- VBIXEXWLHSRNKB-UHFFFAOYSA-N ammonium oxalate Chemical compound [NH4+].[NH4+].[O-]C(=O)C([O-])=O VBIXEXWLHSRNKB-UHFFFAOYSA-N 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 230000004927 fusion Effects 0.000 description 3
- 238000005469 granulation Methods 0.000 description 3
- 230000003179 granulation Effects 0.000 description 3
- 238000000462 isostatic pressing Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 229910001416 lithium ion Inorganic materials 0.000 description 3
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 239000006258 conductive agent Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000005347 demagnetization Effects 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 239000007770 graphite material Substances 0.000 description 2
- 239000002391 graphite-based active material Substances 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000011164 primary particle Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000012216 screening Methods 0.000 description 2
- 238000007873 sieving Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 230000002195 synergetic effect Effects 0.000 description 2
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000009831 deintercalation Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000009830 intercalation Methods 0.000 description 1
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- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 239000011295 pitch Substances 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
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- 239000002002 slurry Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- -1 transition metal salt Chemical class 0.000 description 1
Images
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
-
- 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 relates to the field of lithium secondary batteries, in particular to a preparation method of an artificial graphite cathode active material, which comprises the following steps of carrying out heat treatment on a coke raw material in an atmosphere containing gaseous water to obtain a coke raw material A; wherein the temperature of the heat treatment is 300-600 ℃; dispersing a coke raw material A in a solution containing a transition metal source and an ammonium source, and pressurizing the system by using gas, wherein the pressure is 5-20 MPa, and the temperature is 50-160 ℃; pressurizing, decompressing and collecting to obtain a coke raw material B; mixing the coke raw material B with small particle size and a carbon source, and then carbonizing to obtain carbon C; carbonizing the coke raw material B with large particle size to prepare carbon D; and pressing and molding the carbon C and the carbon D, and then carrying out graphitization treatment to obtain the artificial graphite negative electrode active material. The invention also comprises the material prepared by the preparation method and application thereof. The method can reduce the graphitization treatment time and the treatment cost, and can improve the performance of the material, particularly the rate capability.
Description
Technical Field
The invention belongs to the technical field of lithium battery electrode materials, and particularly relates to a low-energy-consumption catalytic graphitization preparation method of an artificial graphite cathode.
Background
Lithium ion batteries are a typical representative of a novel green rechargeable battery system, and have been widely used in various fields due to their excellent use properties. Graphite has good electrical conductivity, a layered structure suitable for lithium intercalation and deintercalation, and good cycle performance, and is one of the core raw materials of lithium ion batteries.
In recent years, with the rapid development of lithium-ion-battery new energy automobiles, the advantages of rate and cycle characteristics of artificial graphite are increasingly prominent, the artificial graphite becomes a mainstream raw material of a power battery, and the artificial graphite is widely paid attention to cost while being applied to a large number of commercial applications, and becomes a research hotspot.
Currently, the artificial graphite uses petroleum coke or needle coke as a main raw material, and the mainstream production process flow of the artificial graphite cathode material mainly comprises the following 4 steps: crushing raw materials, modifying the surface of powder particles, graphitizing, sieving, demagnetizing and packaging. The graphitization process is to heat the material to a temperature of more than 2800 ℃ in a protective medium (mostly nitrogen) in a high-temperature electric furnace, and the spatial structure of the material is changed, so that the material has good volume density, electric conductivity, thermal conductivity, corrosion resistance and machining performance. In recent years, with the maturity of the domestic needle coke technology and the expansion of scale, the graphitization cost exceeds the raw material cost, and the problem is urgently needed to be solved. The main equipment for graphitizing the negative electrode material is an Acheson furnace, and referring to the electrode graphitization process, powder is put into a graphite crucible, and the graphite crucible is heated up due to the action of resistance, so that carbon powder is converted into artificial graphite through high-temperature heat treatment at the temperature of 2500-3000 ℃. However, the acheson graphitization furnace has high energy consumption per se, and only 30% of electric energy is used for graphitizing the product, so that the graphitizing process in the artificial graphite process has high cost pressure. The graphitization process flow mainly comprises the processes of furnace laying, furnace core building, charging of a cathode material precursor and a heat preservation material body, power transmission, cooling, discharging, packaging and the like. The graphitization in one period generally takes 20-30 days, wherein 40-100 hours for power transmission and temperature rise are key links of a graphitization process. Because the whole process needs high temperature and high energy consumption, the graphitization treatment of a single ton of material needs 7000-14000 ℃ of electricity, and the graphitization process accounts for 50% of the cost of the artificial graphite cathode. Therefore, it is required to develop a new process for reducing the graphitization treatment cost of the artificial graphite and improving the properties of the prepared material.
Disclosure of Invention
Aiming at the problems of high energy consumption and unsatisfactory electrochemical performance of the conventional artificial graphite active material, the invention provides a preparation method of an artificial graphite cathode active material, and aims to provide a preparation method of artificial graphite with low energy consumption and high electrochemical performance.
The second purpose of the invention is to provide the artificial graphite negative electrode material prepared by the preparation method.
The third purpose of the invention is to provide the application of the artificial graphite negative electrode material prepared by the preparation method in the lithium secondary battery and the prepared lithium secondary battery.
A fourth object of the present invention is to provide a lithium secondary battery comprising the artificial graphite active material.
In the prior art, petroleum coke or needle coke is usually crushed and sieved to obtain primary particles, and then the primary particles are mixed with asphalt, carbonized, graphitized and the like to obtain the artificial graphite material. The graphitization process needs high temperature treatment for more than 24 hours at 2800 ℃ to realize rearrangement of carbon atoms and acquisition of high crystalline phase graphite, so that the reversible lithium delithiation performance and high conductivity of the material are improved. However, the graphitization process generally needs heat preservation for more than 30h, the power consumption is extremely high, the preparation cost is high, and the prepared artificial graphite is generally low in tap density and compaction density. To this end, the invention provides the following improvements:
a method for preparing an artificial graphite negative active material, comprising the steps of:
step (1):
carrying out heat treatment on the coke raw material in the atmosphere containing gaseous water to obtain a coke raw material A; wherein the temperature of the heat treatment is 300-600 ℃;
step (2):
dispersing a coke raw material A in a solution containing a transition metal source and an ammonium source, and pressurizing the system by using gas, wherein the pressure is 5-25 MPa, and the temperature is 50-160 ℃;
pressurizing, then decompressing, and collecting to obtain a coke raw material B;
and (3):
mixing the coke raw material B with small particle size and a carbon source, and then carbonizing to obtain carbon C;
carbonizing the coke raw material B with large particle size to prepare carbon D;
the D50 of the coke raw material B with small particle size is 5-12 mu m; the D50 of the coke raw material B with the large particle size is 1.5 times of the D50 of the coke raw material B with the small particle size;
and (4):
and pressing and molding the carbon C and the carbon D, and then carrying out graphitization treatment to obtain the artificial graphite negative electrode active material.
In the invention, the coke raw material is innovatively subjected to gaseous underwater heat treatment, and then is matched with the pressurization treatment of a transition metal source and an ammonium source solution under the assistance of gas, the grading treatment of large and small coke raw materials and the control of process parameters, so that the process and parameter cooperation can be realized, the graphitization difficulty can be effectively reduced, the artificial graphite cathode active material can be obtained with low energy consumption, and more importantly, the prepared material has unexpected advantages in performance.
In the invention, the coke raw material is at least one of petroleum coke, needle coke and pitch coke.
In the invention, the gas-solid heat treatment under gaseous water in the step (1), the gas-solid-liquid three-phase pressurization treatment in the step (2) and the subsequent grading treatment are the key points for synergistically improving the material performance.
Preferably, the volume content of gaseous water in the atmosphere is greater than or equal to 20%, preferably 20 to 100%, and more preferably 50 to 90%.
In the present invention, in the step (1), the atmosphere further contains an oxygen-containing gas. The research of the invention unexpectedly finds that the coke raw material is treated in the combined atmosphere of oxygen-containing atmosphere and gaseous water, so that the method can be used for further cooperating, is beneficial to further improving the adaptability of microstructures and particles, is beneficial to further reducing the graphitization difficulty, and is more beneficial to obtaining the graphite cathode material with high tap density and high performance.
Preferably, the oxygen-containing gas is air or oxygen;
preferably, the volume content of the oxygen-containing atmosphere is 5-20%;
preferably, the atmosphere in step (1) further contains at least one atmosphere of nitrogen and inert gas;
in the preferable step (1), the temperature of the heat treatment is 450 to 550 ℃; in the invention, under the optimal atmosphere and temperature, the graphitization difficulty is reduced, and the capacity and rate capability of the prepared material can be further improved.
Preferably, in step (1), the heat treatment time is 0.5 to 6 hours, preferably 1 to 3 hours.
In the invention, under the special gas-solid treatment in the step (1), the material is further placed in a solution containing a transition metal source and an ammonium source, and gas is utilized for pressurization treatment, so that gas-solid-liquid three-phase treatment can be facilitated, and the process in the step (1) is further matched, so that the particle suitability is further improved, the graphitization difficulty is reduced, and the electrochemical performance of the material is improved.
Preferably, the transition metal source is at least one of a salt, a hydroxide and an oxide of a transition metal;
preferably, the transition metal element is nickel and/or cobalt;
preferably, the transition metal source is at least one of nickel nitrate, cobalt nitrate, nickel hydroxide, cobalt hydroxide, nickel oxide, cobalt oxide and nickel oxalate;
preferably, the ammonium source is at least one of ammonia water, ammonium chloride, nitrate, ammonium sulfate and ammonium acetate;
preferably, in the solution in the step (2), the concentration of the transition metal source is 0.1-5 g/L, and the concentration of the ammonium source is 0.5-20 g/L;
preferably, the weight ratio of the coke raw material a to the transition metal source of the solution is 100.
Preferably, in the step (2), the gas is at least one of nitrogen, an inert gas and an oxygen-containing gas, and is preferably an oxygen-containing gas. It has been found that pressurizing under a preferred oxygen-containing atmosphere helps to further synergistically improve the properties of the material.
In the invention, under the combined control of the solution components, the gas pressurization pressure and the temperature in the treatment stage are further controlled, and the material performance can be further improved by cooperating with the step (1).
Preferably, the temperature in the pressure treatment stage is 60 to 120 ℃, and more preferably 80 to 120 ℃;
in the present invention, the pressure of the pressurized gas is higher than the self-pressure of the heating in the autoclave (P = nRT/V).
Preferably, the pressure for pressurization is 15 to 20MPa;
preferably, the pressure is maintained for 4 to 12 hours.
In the invention, under the combined treatment of the steps (1) and (2), the sectional carbonization grading treatment with large particle size and small particle size is further matched, so that the graphitization difficulty can be further reduced in a synergistic manner, and the electrochemical performance of the prepared material is improved.
In the invention, the large-particle and small-particle coke raw material B can be obtained by classifying the coke raw material into large particles and small particles and then performing the treatment of the steps (1) and (2), or classifying the coke raw material with composite size into the large-particle and small-particle coke raw material B after the treatment of the steps (1) and (2).
Preferably, the D50 of the small-particle-size coke raw material B is 6 to 10 μm;
the ratio of D50 of the large-particle-size coke raw material B to the small-particle-size coke raw material B is 1.5-2.5: 1, preferably 2 to 2.5;
preferably, the carbon source is at least one of soft carbon source, preferably pitch, needle coke, petroleum coke, mesocarbon microbeads and the like;
preferably, the weight ratio of the small-particle-size coke raw material B to the carbon source is 100:2 to 8;
preferably, the carbonization process is performed under negative pressure;
preferably, the negative pressure is 5 to 50Pa;
preferably, the carbonization temperature is 800-1250 ℃, preferably 900-1000 ℃;
preferably, the mass ratio of the carbon C to the carbon D is 1-9:1-9, preferably 1-5:1;
preferably, carbon C and carbon D are compacted by hot isostatic pressing, preferably at a pressure of 50 to 300MPa;
preferably, the temperature for graphitization is 2800-3200 ℃;
preferably, the graphitization time is 10-16 h.
After graphitization treatment, conventional treatments such as crushing, sieving, demagnetizing and the like are carried out to prepare the artificial graphite cathode active material.
The invention relates to a low-energy-consumption catalytic graphitization preparation method of an artificial graphite cathode, which comprises the following steps of:
step (1): one or more of uncalcined petroleum coke, needle coke or pitch coke is used as a raw material and is processed into coarse particles (CKL) and fine particles (XKL) with the particle size of 5-12 mu m by grinding, wherein the particle size of the CKL is 1.5-3 times of that of the XKL;
step (2): respectively placing the coarse particles and the fine particles in the previous step into an atmosphere furnace, and introducing gaseous water (water vapor) or mixed gas of gaseous water and oxygen-containing atmosphere for heat treatment to obtain treated materials, namely h-CKL and h-XKL; the temperature of the heat treatment is 300-600 ℃, and the time is 0.5-6 h;
and (3): respectively dispersing the solutions of the processing material, the transition metal salt and the ammonium source in the step 2 uniformly, pressurizing by using gas, then after the system is cooled to normal pressure and normal temperature, carrying out desolventizing treatment and material drying to respectively obtain s-h-CKL and s-h-XKL; the transition metal source is nickel nitrate, cobalt nitrate, nickel hydroxide, cobalt hydroxide, nickel oxide, cobalt oxide, nickel oxalate and the like.
And (4): putting the s-h-CKL into an atmosphere furnace for vacuum carbonization to obtain a carbonized material (CKL-C);
and (5): placing the s-h-XKL and asphalt in a fusion machine for granulation, and then placing in a vacuum furnace for vacuum carbonization to obtain a carbonized material (XKL-C/C);
and (6): uniformly mixing the CKL-C and the XKL-C/C according to a certain proportion, compacting in an isostatic press, graphitizing in a graphitizing furnace, and finally performing conventional depolymerization, demagnetization and screening to obtain the artificial graphite cathode material.
The invention also provides the artificial graphite cathode active material prepared by the preparation method.
The preparation method of the invention can endow the material with special physical and chemical properties and can show excellent electrochemical properties.
The invention also provides application of the artificial graphite negative electrode active material, and the artificial graphite negative electrode active material is used as a negative electrode active material. Preferably, it is used as an anode active material for preparing a lithium secondary battery.
In the invention, the artificial graphite cathode active material prepared by the invention can be prepared into required batteries and parts thereof based on the existing processes, equipment and means.
For example, the artificial graphite material is used as a negative electrode active material and is used for compounding with a conductive agent and a binder to prepare a negative electrode material. The conductive agent and the adhesive are all materials which can be known in the industry.
In a further preferable application, the negative electrode material is arranged on the surface of a negative electrode current collector and used for preparing a negative electrode. The negative electrode may be formed by applying the negative electrode material of the present invention to a current collector by a conventional method, for example, by a coating method. The current collector is any material known in the industry.
In a further preferred application, the negative electrode, the positive electrode, the separator and the electrolyte are assembled into a lithium secondary battery.
A lithium secondary battery comprises the artificial graphite negative electrode material prepared by the preparation method.
The negative pole piece of the lithium secondary battery comprises the graphite negative pole material.
Preferably, the lithium secondary battery is a lithium ion battery.
Has the advantages that:
(1) In the invention, the coke raw material is innovatively subjected to gas-state underwater heat treatment, and then is matched with the pressurization treatment of a transition metal source and an ammonium source solution under the assistance of gas, the grading treatment of large and small coke raw materials is further matched with the control of process parameters, so that the process and parameter cooperation can be realized, the graphitization difficulty can be effectively reduced, the artificial graphite cathode active material can be obtained with low energy consumption, and more importantly, the prepared material has unexpected advantages in performance.
(2) The main raw materials and the materials are wide in source and low in cost, and the adopted mixing, fusion granulation, heat treatment and graphitization processes are simple and convenient, strong in controllability, easy to realize large-scale production and good in practical prospect.
Drawings
FIG. 1 is an SEM photograph of the activated material (h-CKL) obtained in step (2) of example 1.
FIG. 2 is an SEM photograph of the final material obtained in example 1.
Detailed Description
The specific procedures of the present invention are illustrated below by way of examples, it being understood that these examples are intended to illustrate the invention and are not intended to limit the scope of the invention in any way. Various procedures and methods not described in detail herein are conventional methods well known in the art.
Example 1
Step (1): respectively obtaining two raw materials of coarse particles (CKL) with the particle size of 14 mu m and fine particles (XKL) with the particle size of 6 mu m from uncalcined petroleum coke through airflow milling treatment;
step (2): respectively placing the coarse particles and the fine particles in the previous step into an atmosphere furnace, heating the atmosphere furnace to 550 ℃ (marked as T1), introducing gaseous water for heat preservation pretreatment for 2h, and respectively obtaining two pretreatment materials (h-CKL and h-XKL);
and (3): respectively placing the pretreatment materials into a solution of nickel acetate and ammonium oxalate, placing the solution into a pressure-resistant kettle, introducing nitrogen (pressurized gas) into the kettle, controlling the temperature to be 120 ℃ (labeled as T2), keeping the system pressure to be 15MPa (labeled as P1), maintaining for 5h, then releasing pressure, and after the system returns to normal pressure and normal temperature, performing water evaporation operation on the obtained slurry to respectively obtain two treatment materials of s-h-CKL and s-h-XKL; in the solution, the concentration of nickel acetate is 2g/L, the concentration of ammonium oxalate is 5g/L, and the weight ratio of the pretreatment material to the nickel acetate in the solution is 100;
and (4): placing the s-h-CKL in an atmosphere furnace, heating to 1000 ℃ at a speed of 5 ℃/min under the protection of argon (marked as T3), vacuumizing the system to enable the pressure to be 10Pa, preserving heat for 5h, and cooling to room temperature to obtain a carbonized material (CKL-C);
and (5): mixing s-h-XKL and asphalt according to the mass ratio of 100:2, placing the mixture in a fusion machine for granulation treatment, and then placing the mixture in a vacuum furnace for vacuum carbonization treatment in the same way as the step (4)) to obtain a carbonized material (XKL-C/C);
and (6): mixing CKL-C and XKL-C/C according to the mass ratio of 1:1, pressing and molding in an isostatic pressing machine under the pressure of 150MPa to obtain an isostatic pressing block, then placing the isostatic pressing block in a graphitization furnace for graphitization treatment, keeping the temperature at 2900 ℃ for 12h, and finally performing conventional depolymerization, demagnetization and screening to obtain the artificial graphite cathode material.
According to GB/T243358-2009, the graphite electrode is taken as a working electrode, metal lithium is taken as a negative electrode, and 1mol/L LiPF 6 The EC/EMC (volume ratio 1:1) is electrolyte, the PE-PP composite membrane is a diaphragm, and the CR2025 button cell is assembled in a dry glove box filled with argon, and electrochemical performance detection is carried out in a voltage range of 0.001-2.0V at room temperature.
Example 2
Compared with the embodiment 1, the difference is only that in the step (2), the gaseous water atmosphere is replaced by the gaseous water-oxygen composite gas, and the heat preservation pretreatment process is carried out, wherein in the composite gas, the volume ratio of the gaseous water to the gaseous oxygen is 8:2.
Example 3
Compared with example 1, the difference is only that the temperature of T1 is changed to 350 ℃; the other operations and parameters were the same as in example 1.
Example 4
Compared with example 1, the only difference is that the temperature of T1 is changed to 500 ℃; the other operations and parameters were the same as in example 1.
Example 5
Compared with the example 1, the difference is only that in the step (3), the solution is an aqueous solution of cobalt nitrate and ammonium nitrate, wherein the concentration of the cobalt nitrate is 2g/L, the concentration of the ammonium nitrate is 5g/L, and the weight ratio of the pretreatment material to the cobalt nitrate in the solution is 100;
example 6
The only difference compared to example 1 is that in step (3), the pressurized gas is air. The other operations and parameters were the same as in example 1.
Example 7
The only difference compared with example 1 is that in step (3), P1 is at a pressure of 10MPa and a temperature of 80 ℃.
Example 8
The only difference compared to example 1 is that in step (3), the pressure of P1 is 20MPa and the temperature is 90 ℃.
Example 9
The only difference compared with example 1 is that in step (4), the temperature of T3 is 900 ℃, and in (5), the mass ratio of s-h-XKL to asphalt is 100:8; and (6): mixing CKL-C and XKL-C/C according to the mass ratio of 1:5; the temperature for graphitization is 3000 ℃ and the time is 10h.
Example 10
Compared with the example 1, the difference is only that in the step (2), the gaseous water atmosphere is replaced by the gaseous water-oxygen composite gas, the heat preservation pretreatment process is carried out, wherein the volume ratio of the gaseous water to the gaseous oxygen in the composite gas is 9:1, and the temperature of T1 is 450 ℃. In the step (3), the pressurized gas is air.
Comparative example 1
The only difference compared to example 1 is that in step (2) nitrogen is used instead of said gaseous water, and the other operations and parameters are the same as in example 1.
Comparative example 2
The only difference compared with example 1 is that in step (2), the temperature of T1 is 700 ℃ and the other operations and parameters are the same as in example 1.
Comparative example 3
Compared with example 1, the only difference is that the process of step (2) is replaced, and the step (2) is different: and (2) respectively and uniformly mixing the coarse particles and the fine particles obtained in the step (1) with 0.5M potassium hydroxide (the mass ratio of the potassium hydroxide to the coarse particles/the fine particles is 3:1), placing the mixture into an atmosphere furnace, heating the mixture to 550 ℃ (marked as T1) under the protection of nitrogen, and carrying out heat preservation treatment for 2 hours to respectively obtain two pretreatment materials (h-CKL and h-XKL).
Comparative example 4
Compared with the example 1, the difference is only that in the step (3), nickel acetate is not added into the solution, the solid-to-liquid ratio of the pretreatment material and the solution is the same as that of the example 1, and other operations and parameters are the same as those of the example 1.
Comparative example 5
The only difference compared to example 1 is that in step (3), no ammonium oxalate is added to the solution and the other operations and parameters are the same as in example 1.
Comparative example 6
The only difference from example 1 is that in step (3), no pressurized gas is introduced for pressurization, and the other operations and parameters are the same as those of example 1.
Comparative example 7
The only difference compared to example 1 is that in step (3), the temperature of T2 is 180 ℃ and the other operations and parameters are the same as in example 1.
Comparative example 8
The only difference compared to example 1 is that in step (6), only CKL-C is used for pressing and graphitization.
Comparative example 9
Compared with the embodiment 1, the difference is only that in the step (6), only XKL-C/C is used for pressing and graphitizing.
The results of the tests on the materials obtained in the above examples and comparative examples are as follows:
therefore, the coke raw material is innovatively subjected to gas-state underwater heat treatment, and is matched with the pressurization treatment of a transition metal source and an ammonium source solution under the assistance of gas, the grading treatment of the large coke raw material and the small coke raw material, and the control of process parameters, so that the process and parameter cooperation can be realized, the graphitization difficulty can be effectively reduced, the artificial graphite cathode active material can be obtained with low energy consumption, and more importantly, the prepared material has unexpected advantages in performance. On the basis, the electrochemical performance, especially the rate capability, of the material can be further improved in a synergistic manner by further matching with the combination of parameters such as modified atmosphere, pressurized gas and the like.
Claims (10)
1. A preparation method of an artificial graphite negative electrode active material is characterized by comprising the following steps:
step (1):
carrying out heat treatment on the coke raw material in the atmosphere containing gaseous water to obtain a coke raw material A; wherein the temperature of the heat treatment is 300-600 ℃;
step (2):
dispersing a coke raw material A in a solution containing a transition metal source and an ammonium source, and pressurizing the system by using gas, wherein the pressure is 5-25 MPa, and the temperature is 50-160 ℃;
pressurizing, decompressing and collecting to obtain a coke raw material B;
and (3):
mixing the coke raw material B with small particle size and a carbon source, and then carbonizing to obtain carbon C;
carbonizing the coke raw material B with large particle size to prepare carbon D;
the D50 of the coke raw material B with small grain size is 5-12 mu m; the D50 of the coke raw material B with the large particle size is 1.5 times of the D50 of the coke raw material B with the small particle size;
and (4):
and pressing and molding the carbon C and the carbon D, and then carrying out graphitization treatment to obtain the artificial graphite negative electrode active material.
2. The method of preparing the artificial graphite negative active material of claim 1, wherein the coke raw material is at least one of petroleum coke, needle coke, and pitch coke.
3. The method for preparing the artificial graphite anode active material according to claim 1, wherein in the step (1), the atmosphere further contains an oxygen-containing gas;
preferably, the oxygen-containing gas is air or oxygen;
preferably, the volume content of the oxygen-containing atmosphere is 5-20%;
preferably, the atmosphere in step (1) further contains at least one atmosphere of nitrogen and inert gas;
preferably, the volume content of the gaseous water in the atmosphere is 20-50%.
4. The method for preparing the artificial graphite negative electrode active material according to claim 1 or 3, wherein, in the step (1), the temperature of the heat treatment is 450 to 550 ℃;
preferably, in the step (1), the heat treatment time is 0.5 to 6 hours.
5. The method for preparing the artificial graphite negative electrode active material according to claim 1, wherein the transition metal source is at least one of a salt, a hydroxide, and an oxide of a transition metal;
preferably, the transition metal element is nickel and/or cobalt;
preferably, the transition metal source is at least one of nickel nitrate, cobalt nitrate, nickel hydroxide, cobalt hydroxide, nickel oxide, cobalt oxide and nickel oxalate;
preferably, the ammonium source is at least one of ammonia water, ammonium chloride, nitrate, ammonium sulfate and ammonium acetate;
preferably, in the solution in the step (2), the concentration of the transition metal source is 0.1-5 g/L, and the concentration of the ammonium source is 0.5-20 g/L;
preferably, the weight ratio of the coke raw material A to the transition metal source of the solution is 100.
6. The method for preparing an artificial graphite negative electrode active material according to claim 1 or 5, wherein, in the step (2), the gas is at least one of nitrogen, an inert gas, and an oxygen-containing gas, preferably an oxygen-containing gas;
preferably, the temperature of the pressure treatment stage is 60 to 120 ℃;
preferably, the pressure for pressurization is 15 to 20MPa;
preferably, the pressure is maintained for 4 to 12 hours.
7. The method for preparing the artificial graphite negative active material according to claim 1 or the above, wherein the D50 of the small-particle-size coke raw material B is 6 to 10 μm;
the ratio of D50 of the large-particle-size coke raw material B to the small-particle-size coke raw material B is 1.5-2.5: 1;
preferably, the carbon source is a soft carbon source, preferably at least one of asphalt, needle coke, petroleum coke, mesocarbon microbeads and the like;
preferably, the weight ratio of the small-particle-size coke raw material B to the carbon source is 100:2 to 8 percent;
preferably, the carbonization process is carried out under negative pressure;
preferably, the negative pressure is 5 to 50Pa;
preferably, the temperature of carbonization is 800-1250 ℃;
preferably, the mass ratio of the carbon C to the carbon D is 1-9:1-9;
preferably, carbon C and carbon D are compacted by hot isostatic pressing, preferably at a pressure of 50 to 300MPa;
preferably, the temperature for graphitization is 2800-3200 ℃;
preferably, the graphitization time is 10-16 h.
8. An artificial graphite negative electrode active material produced by the production method according to any one of claims 1 to 7.
9. Use of the artificial graphite negative electrode active material according to claim 8 as a negative electrode active material;
preferably, it is used as an anode active material for the preparation of a lithium secondary battery.
10. A lithium secondary battery comprising the artificial graphite negative active material according to claim 8;
preferably, the artificial graphite negative electrode active material is contained in the negative electrode of the lithium secondary battery.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10255770A (en) * | 1997-03-14 | 1998-09-25 | Adokemuko Kk | Manufacture of graphite material for battery and battery |
| CN101882685A (en) * | 2010-03-31 | 2010-11-10 | 孙公权 | Magnesium-oxygen battery for seawater underwater |
| WO2022121136A1 (en) * | 2020-12-10 | 2022-06-16 | 广东凯金新能源科技股份有限公司 | Artificial graphite negative electrode material for high-rate lithium ion battery and preparation method therefor |
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10255770A (en) * | 1997-03-14 | 1998-09-25 | Adokemuko Kk | Manufacture of graphite material for battery and battery |
| CN101882685A (en) * | 2010-03-31 | 2010-11-10 | 孙公权 | Magnesium-oxygen battery for seawater underwater |
| WO2022121136A1 (en) * | 2020-12-10 | 2022-06-16 | 广东凯金新能源科技股份有限公司 | Artificial graphite negative electrode material for high-rate lithium ion battery and preparation method therefor |
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