CN109599546B - Asphalt carbon-coated natural mixed graphite material and method for preparing lithium ion battery cathode by using same - Google Patents

Asphalt carbon-coated natural mixed graphite material and method for preparing lithium ion battery cathode by using same Download PDF

Info

Publication number
CN109599546B
CN109599546B CN201811477232.0A CN201811477232A CN109599546B CN 109599546 B CN109599546 B CN 109599546B CN 201811477232 A CN201811477232 A CN 201811477232A CN 109599546 B CN109599546 B CN 109599546B
Authority
CN
China
Prior art keywords
graphite
asphalt
carbon
mixed
mixed graphite
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201811477232.0A
Other languages
Chinese (zh)
Other versions
CN109599546A (en
Inventor
张治安
谢杨洋
尹盟
胡均贤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Guangxi Chenyu New Material Co ltd
Original Assignee
Central South University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Central South University filed Critical Central South University
Priority to CN201811477232.0A priority Critical patent/CN109599546B/en
Publication of CN109599546A publication Critical patent/CN109599546A/en
Application granted granted Critical
Publication of CN109599546B publication Critical patent/CN109599546B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Carbon And Carbon Compounds (AREA)

Abstract

The invention discloses an asphalt carbon-coated natural mixed graphite material and a method for preparing a lithium ion battery cathode by using the same. The preparation process of the asphalt carbon-coated natural mixed graphite material comprises the following steps: ball-milling and mixing microcrystalline graphite and crystalline flake graphite to obtain mixed graphite powder; carrying out solvothermal reaction on the mixed graphite powder, asphalt liquid and an organic solvent to obtain a precursor material; and (3) performing pre-carbonization and carbonization treatment on the precursor material, and purifying by adopting acid to obtain the material. The method is simple, low in cost and suitable for large-scale production; the prepared asphalt carbon-coated natural mixed graphite material has the advantages of large average interlayer spacing, moderate specific surface area, good conductivity and the like, is used as a negative electrode material for preparing a lithium ion battery, shows good cycle stability and high specific capacity, and has a large-scale application prospect.

Description

Asphalt carbon-coated natural mixed graphite material and method for preparing lithium ion battery cathode by using same
Technical Field
The invention relates to a carbon material, in particular to a composite carbon material formed by coating mixed natural graphite with asphalt carbon, a preparation method of the asphalt carbon-coated natural mixed graphite material and application of the asphalt carbon-coated natural mixed graphite material as a lithium ion battery cathode material, and belongs to the technical field of batteries.
Background
Microcrystalline graphite is one of the natural graphites. The microcrystalline graphite is a compact aggregate formed by tiny natural graphite crystals, and has the characteristics of high temperature resistance, heat transfer, electric conduction, acid and alkali resistance, good plasticity and the like. The microcrystalline graphite in China is abundant in resources, and the found resource reserves reach 3,458.1 ten thousand tons. The reserves of Hunan province are first in China, account for 74.7 percent of China, and the mineral products have excellent quality. However, because of less development and utilization research, a great deal of microcrystalline graphite is used as middle and low-end carbon materials such as casting materials, refractory materials, pencils, dyes and the like for a long time, and the resource utilization degree is not high overall. Wherein the output of the microcrystalline graphite is about 50 percent and is used as fuel in the form of coal, which causes great waste to natural resources.
Graphite materials are always the first choice of negative electrode materials for lithium secondary batteries, and at present, natural flake graphite or artificial graphite is generally adopted as the negative electrode material for commercial lithium secondary batteries. However, unmodified graphite has the disadvantages of low specific capacity, poor rate capability, excessively low discharge plateau and the like. The microcrystalline graphite has the characteristics of small crystal grain, orientation dispersion and near isotropy, is favorable for the rapid migration of ions, has a disordered layer structure to form a large number of defects, can obtain a large number of active sites as a negative electrode material, but has the defects of overlarge specific surface area, easy generation of larger irreversible capacity and low coulombic efficiency in the first circle. Therefore, it is difficult to directly apply the microcrystalline graphite to a power battery negative electrode material.
Disclosure of Invention
Aiming at the defects of microcrystalline graphite in the use process as a lithium ion battery cathode material in the prior art, the invention aims to provide an asphalt carbon-coated natural mixed graphite material with high porosity, proper specific surface area and good conductivity, which can be used for preparing the lithium ion battery cathode material with good cycling stability and long service life.
The invention also aims to provide a method for preparing the asphalt carbon-coated natural mixed graphite material, which has the advantages of low raw material cost, environmental protection, high controllability, good repeatability and easy realization of industrial preparation.
The third purpose of the invention is to provide an application of the asphalt carbon-coated natural mixed graphite material in a lithium ion battery, wherein the asphalt carbon-coated natural mixed graphite material has the advantages of high porosity, proper specific surface area, good conductivity and the like, and the prepared lithium ion battery has the advantages of high specific capacity, good cycle stability, long service life and the like.
In order to achieve the technical purpose, the invention provides a preparation method of an asphalt carbon-coated natural mixed graphite material, which comprises the following steps:
1) ball-milling and mixing microcrystalline graphite and crystalline flake graphite to obtain mixed graphite powder;
2) carrying out solvothermal reaction on the mixed graphite powder, asphalt liquid and an organic solvent to obtain a precursor material;
3) and (3) performing pre-carbonization and carbonization treatment on the precursor material, and purifying by adopting acid to obtain the material.
According to the technical scheme, the microcrystalline graphite and the crystalline flake graphite are subjected to ball milling crushing and mixing together, so that the two natural graphites are fully mixed, and part of the microcrystalline graphite is embedded between the crystalline flake graphite layers and coated on the surfaces of the crystalline flake graphite. And then mixing the mixed graphite with asphalt and an organic solvent, carrying out solvothermal reaction, and guiding the asphalt carbon to coat the mixed graphite to form a uniform and stable coating layer by utilizing the isotropy of natural microcrystalline graphite, wherein part of asphalt is carbonized in the solvothermal reaction process to generate the asphalt carbon coating layer on the surface of the mixed graphite, and the mixed graphite is formed into a mixed graphite kernel by connecting disordered microcrystalline graphite between ordered flake graphite sheets, and the structure of the microcrystalline graphite between the flake graphite is more favorable for conduction among electrons and storage of lithium ions. The carbonization degree is improved through two-step carbonization reaction. After two-step carbonization reaction, mixed acid purification treatment is carried out, the porosity of the mixed graphite can be improved by the treatment step, if purification is carried out before carbonization, the asphalt liquid is easy to fill the inner hole of the mixed graphite in the coating process, the porosity is reduced, purification is carried out after carbonization, the effect of a micropore template is achieved by ash in natural graphite, the original inner micropores of the mixed graphite can be reserved after acid purification, and the pore structure of the mixed graphite is increased. Therefore, the asphalt carbon-coated natural mixed graphite material has good conductivity, high porosity, proper specific surface area, mutual cross-linking of pore channels and rich pore channels, can provide rich channels for the transmission of lithium ions and electrolyte, and can also provide a certain buffer effect on the problem of volume expansion and shrinkage caused by the desorption of the lithium ions.
In the preferred scheme, the mass ratio of the microcrystalline graphite to the crystalline flake graphite is 1: 5-5: 1; the microcrystalline graphite and the crystalline flake graphite are crushed to the granularity of below 100 meshes.
In a preferred embodiment, the ball milling conditions are as follows: the mass ratio of the ball material is 20-40: 1, the rotating speed is 300-500 rpm, and the time is 2-12 h.
The asphalt liquid of the present invention refers to liquid asphalt.
In the preferable scheme, the mass ratio of the mixed graphite powder to the asphalt liquid is 1: 10-10: 1.
In a preferred embodiment, the organic solvent includes at least one of formic acid, acetic acid, methanol, ethanol, ethylene glycol, isopropanol, butanol, acetonitrile, dichloromethane, chloroform, N-dimethylformamide, N-dimethylacetamide, and N-methylpyrrolidone. Preferably at least one of ethanol, isopropanol and N-methylpyrrolidone.
In a preferred embodiment, the solvothermal reaction conditions are as follows: the temperature is 80-400 ℃, and the time is 2-6 hours.
In the preferred scheme, the precursor material is pre-carbonized at 350-750 ℃ for 2-12 hours in a protective atmosphere and then carbonized at 800-1200 ℃ for 2-12 hours. In a preferred scheme, the precursor material is placed in a protective atmosphere, pre-carbonized at 450-750 ℃ for 4-8 hours, and carbonized at 900-1100 ℃ for 4-8 hours.
In a preferred scheme, the acid purification process adopts HCl/HF mixed acid. The ash content in the mixed graphite can be deeply removed by adopting HCl/HF mixed acid, so that the carbon content reaches more than 99 percent.
In a preferable scheme, the HCl/HF mixed acid is obtained by mixing concentrated hydrochloric acid, concentrated hydrofluoric acid and water according to a volume ratio of 0.8-1.5: 1: 0.5-1. Concentrated hydrochloric acid and concentrated hydrofluoric acid are commercially available commercial grade conventional acids.
In a preferred embodiment, the acid purification process comprises: and (3) placing the carbonized product in HCl/HF mixed acid, and soaking for 12-36 hours at the temperature of 80-100 ℃. The ash in the mixed graphite can be fully removed through mixed acid purification, and the main component of the ash is SiO2、Al2O3、Fe2O3And metal oxides such as MgO. After acid purification, the asphalt carbon-coated natural mixed graphite is washed by conventional water and alcohol, and ultrasonic assistance can be performed in the washing process.
The invention also provides a natural mixed graphite material coated with the asphalt carbon, which is prepared by the preparation method.
Preferred embodiment, theThe asphalt carbon-coated natural mixed graphite material has a core-shell structure, wherein the shell is an asphalt carbon layer, the core is natural mixed graphite, and the specific surface area of the asphalt carbon-coated natural mixed graphite material is 1-50 m2/g。
The invention also provides an application of the asphalt carbon-coated natural mixed graphite material as a negative electrode material of a lithium ion battery.
The preparation method of the lithium ion battery negative electrode can adopt the existing method, for example, the pitch carbon-coated natural mixed graphite material obtained by the invention is mixed with a conductive agent and a binder, and is coated on a copper foil current collector by a coating method to prepare the lithium ion battery negative electrode.
The invention discloses a method for preparing a lithium ion battery by using a pitch carbon-coated natural mixed graphite material as a negative electrode material and a performance detection method, wherein the method comprises the following steps: weighing the asphalt carbon-coated natural mixed graphite material, adding 10 wt.% of Super P as a conductive agent, 10 wt.% of polyvinylidene fluoride (PVDF) as a binder, fully grinding, adding less N-methylpyrrolidone (NMP), mixing to form uniform black pasty slurry, coating the slurry on a copper foil current collector to serve as a test electrode, assembling a button cell by taking a metal lithium sheet as a contrast electrode, and adopting an electrolytic liquid system of 1M LiPF6DEC (1: 1). The charge-discharge current density used for testing the cycle performance is 100 mA/g.
Compared with the prior art, the invention has the following advantages:
1. the asphalt carbon-coated natural mixed graphite material is prepared by taking asphalt, microcrystalline graphite and crystalline flake graphite as raw materials and adopting the processes of solvothermal reaction combined with low-temperature pre-carbonization, high-temperature carbonization and the like, and has the advantages of simple process, low raw material cost and contribution to industrial production.
2. The asphalt carbon-coated natural mixed graphite material has the advantages that the asphalt carbon layer of the shell has good mechanical strength, the problem of volume expansion of lithium ions in the process of embedding and removing lithium ions between mixed graphite can be solved, the circulation stability of the graphite material is improved, the inner core is formed by connecting ordered-disordered-layer-structured microcrystalline graphite among ordered flake graphite sheets, and the structure of the ordered-disordered-layer-structured microcrystalline graphite among the flake graphite is more favorable for conduction among electrons and storage of lithium ions, so that the mixed graphite has good electrical conductivity and high lithium storage property. Meanwhile, the mixed graphite has defects formed by a disordered layer structure, and can provide a large number of active sites for lithium ion storage.
3. The asphalt carbon of the invention coats a large number of micropores formed by the ordered-disordered layer structure of the microcrystalline graphite in the natural mixed graphite material, and the ash content and the original internal micropores of the mixed graphite are reserved by a method of coating asphalt firstly and then pickling and purifying, and the abundant micropores jointly form a lithium ion and electrolyte transmission channel. The carbon-coated mixed graphite of the asphalt reduces the specific surface area of the mixed graphite, reduces the irreversible capacity loss and improves the coulombic efficiency of the first circle.
4. The asphalt carbon-coated natural mixed graphite material disclosed by the invention is applied to lithium ion batteries, and has the advantages of high cycle stability, long cycle life and the like.
Detailed Description
The present invention is further described in detail below with reference to specific embodiments, but the scope of the present invention is not limited by the claims.
Example 1
10g of natural microcrystalline graphite and 5g of crystalline flake graphite are taken and sieved by a 100-mesh sieve through ball milling, the mass ratio of ball materials in the ball milling process is 30:1, the rotating speed is 400rpm, the time is 6 hours, and the tap density of the obtained powder is 0.98g/cm3(ii) a Putting the dried asphalt-coated mixed graphite composite material into a porcelain boat, introducing nitrogen into a quartz tube furnace for protection, pre-carbonizing at the low temperature of 450 ℃ for 4 hours, and then carbonizing at the high temperature of 900 ℃ for 4 hours; cooling to room temperature, washing the obtained mixed graphite carbon material with deionized water for 3 times, drying in vacuum at 80 ℃ for 6 hours, preparing 100ml of mixed acid solution by using concentrated hydrochloric acid, concentrated hydrofluoric acid and deionized water in a ratio of 5:3:2, pouring the mixed acid solution into the asphalt-coated mixed graphite composite material, heating and stirring by using a magnetic stirrer at the stirring temperature of 80 ℃, and treating the mixed acid for 12 hoursWhen the current is over; filtering and washing for 3 times by using deionized water, and then performing ultrasonic oscillation cleaning by using 100ml of absolute ethyl alcohol to remove ash impurities remained in micropores, wherein the ultrasonic oscillation time is 2 hours; then filtering and washing the mixture for 3 times by using deionized water again; putting the mixture into an oven, and keeping the temperature at 60 ℃ for 6 hours; thus obtaining the asphalt carbon-coated natural mixed graphite carbon negative electrode material.
Weighing 80 wt% of the asphalt carbon-coated natural mixed graphite material prepared in the embodiment, adding 10 wt% of Super P as a conductive agent, 10 wt% of polyvinylidene fluoride (PVDF) as a binder, fully grinding, adding less N-methyl pyrrolidone (NMP), mixing to form uniform black paste slurry, coating the slurry on a copper foil current collector to serve as a test electrode, and assembling a metal lithium sheet serving as a contrast electrode to form an R2025 button cell, wherein an electrolytic liquid system is 1M LiPF6DEC (1: 1). Testing the cycle performance under the current density of 500 mA/g; the rate performance of the battery is tested under different current densities of 1000mA/g, 2000mA/g and the like. The obtained test results show that the lithium battery cathode prepared in the embodiment has good electrochemical performance: under the current density of 500mA/g, after circulating for 300 circles, the specific capacity of 348mA/g can still be kept, and after circulating for 2000 circles, the capacity of 97 percent can still be kept; the specific capacities of 336mAh/g and 319mAh/g can be respectively maintained under the discharge densities of 1000mA/g and 2000 mA/g.
Example 2
10g of natural microcrystalline graphite and 5g of crystalline flake graphite are taken and sieved by a 100-mesh sieve through ball milling, the mass ratio of ball materials in the ball milling process is 40:1, the rotating speed is 300rpm, the time is 8 hours, and the tap density of the obtained powder is 0.98g/cm3(ii) a Putting the dried asphalt-coated mixed graphite composite material into a porcelain boat, introducing nitrogen into a quartz tube furnace for protection, pre-carbonizing at the low temperature of 450 ℃ for 6 hours, and then carbonizing at the high temperature of 900 ℃ for 4 hours; cooling to room temperature, washing the obtained mixed graphite carbon material with deionized water for 3 times, vacuum drying at 80 deg.C for 6 hr, preparing 100ml mixed acid solution with concentrated hydrochloric acid, concentrated hydrofluoric acid and deionized water at ratio of 5:3:2, pouring the mixed acid solution into the asphalt coating mixtureHeating and stirring the graphite composite material by using a magnetic stirrer, wherein the stirring temperature is 80 ℃, and the treatment time of mixed acid is 12 hours; filtering and washing for 3 times by using deionized water, and then performing ultrasonic oscillation cleaning by using 100ml of absolute ethyl alcohol to remove ash impurities remained in micropores, wherein the ultrasonic oscillation time is 2 hours; then filtering and washing the mixture for 3 times by using deionized water again; putting the mixture into an oven, and keeping the temperature at 60 ℃ for 6 hours; thus obtaining the asphalt carbon-coated natural mixed graphite carbon negative electrode material.
Weighing 80 wt% of the asphalt carbon-coated natural mixed graphite material prepared in the embodiment, adding 10 wt% of Super P as a conductive agent, 10 wt% of polyvinylidene fluoride (PVDF) as a binder, fully grinding, adding less N-methyl pyrrolidone (NMP), mixing to form uniform black paste slurry, coating the slurry on a copper foil current collector to serve as a test electrode, and assembling a metal lithium sheet serving as a contrast electrode to form an R2025 button cell, wherein an electrolytic liquid system is 1M LiPF6DEC (1:1), at a current density of 500mA/g, to test the cycling performance; the rate performance of the battery is tested under different current densities of 1000mA/g, 2000mA/g and the like. The obtained test results show that the lithium battery cathode prepared in the embodiment has good electrochemical performance: under the current density of 500mA/g, after circulating for 300 circles, the specific capacity of 349mA/g can still be kept, and after circulating for 2000 circles, the capacity of 96% can still be kept; under the discharge densities of 1000mA/g and 2000mA/g, the specific capacities of 331mAh/g and 314mAh/g can be still respectively maintained.
Example 3
Ball-milling 10g of natural microcrystalline graphite and 10g of crystalline flake graphite, sieving the materials through a 100-mesh sieve, wherein the mass ratio of the materials in the ball-milling process is 20:1, the rotating speed is 300rpm, the time is 4 hours, and the tap density of the obtained powder is 1.00g/cm3(ii) a Putting the dried asphalt-coated microcrystalline graphite composite material into a porcelain boat, introducing nitrogen into a quartz tube furnace for protection, pre-carbonizing at a low temperature of 400 ℃ for 4 hours, and then carbonizing at a high temperature of 900 ℃ for 6 hours; cooling to room temperature, washing the obtained microcrystalline graphite carbon material with deionized water for 3 times, and vacuum drying at 80 deg.C for 6 hrPreparing 100ml of mixed acid solution by concentrated hydrochloric acid, concentrated hydrofluoric acid and deionized water in a ratio of 5:4:1, pouring the mixed acid solution into the asphalt-coated mixed graphite composite material, heating and stirring by using a magnetic stirrer, wherein the stirring temperature is 80 ℃, and the mixed acid treatment time is 12 hours; filtering and washing for 3 times by using deionized water, and then performing ultrasonic oscillation cleaning by using 100ml of absolute ethyl alcohol to remove ash impurities remained in micropores, wherein the ultrasonic oscillation time is 2 hours; then filtering and washing the mixture for 3 times by using deionized water again; putting the mixture into an oven, and keeping the temperature at 60 ℃ for 6 hours; thus obtaining the asphalt carbon-coated natural mixed graphite carbon negative electrode material.
Weighing 80 wt% of the asphalt carbon-coated natural mixed graphite material prepared in the embodiment, adding 10 wt% of Super P as a conductive agent, 10 wt% of polyvinylidene fluoride (PVDF) as a binder, fully grinding, adding less N-methyl pyrrolidone (NMP), mixing to form uniform black paste slurry, coating the slurry on a copper foil current collector to serve as a test electrode, and assembling a metal lithium sheet serving as a contrast electrode to form an R2025 button cell, wherein an electrolytic liquid system is 1M LiPF6DEC (1:1), at a current density of 500mA/g, to test the cycling performance; the rate performance of the battery is tested under different current densities of 1000mA/g, 2000mA/g and the like. The obtained test results show that the lithium battery cathode prepared in the embodiment has good electrochemical performance: under the current density of 500mA/g, after circulating for 300 circles, the specific capacity of 345mA/g can still be kept, and after circulating for 2000 circles, the capacity of 96% can still be kept; under the discharge densities of 1000mA/g and 2000mA/g, the specific capacities of 332mAh/g and 317mAh/g can be still respectively maintained.
Comparative example 1
Taking 15g of natural crystalline flake graphite, ball-milling and screening the natural crystalline flake graphite by a 100-mesh screen, wherein the mass ratio of balls to materials in the ball-milling process is 30:1, the rotating speed is 400rpm, the time is 6 hours, and the tap density of the obtained powder is 1.01g/cm3(ii) a Putting 6g of asphalt liquid and the mixture into a porcelain boat, introducing nitrogen into a quartz tube furnace for protection, pre-carbonizing at the low temperature of 450 ℃ for 4 hours, and then carbonizing at the high temperature of 900 ℃ for 4 hours; cooling to room temperature, washing the obtained graphite carbon material with deionized water for 3 times, vacuum drying at 80 ℃ for 6 hours, and preparing 1 from concentrated hydrochloric acid, concentrated hydrofluoric acid and deionized water in a ratio of 5:3:200ml of mixed acid solution, pouring the mixed acid solution into the asphalt-coated mixed graphite composite material, and heating and stirring the mixed acid solution by using a magnetic stirrer, wherein the stirring temperature is 80 ℃, and the mixed acid treatment time is 12 hours; filtering and washing for 3 times by using deionized water, and then performing ultrasonic oscillation cleaning by using 100ml of absolute ethyl alcohol to remove ash impurities remained in micropores, wherein the ultrasonic oscillation time is 2 hours; then filtering and washing the mixture for 3 times by using deionized water again; putting the mixture into an oven, and keeping the temperature at 60 ℃ for 6 hours; and obtaining the pitch carbon coated graphite carbon cathode material.
Weighing 80 wt% of the asphalt carbon-coated graphite material prepared in the embodiment, adding 10 wt% of Super P as a conductive agent, 10 wt% of polyvinylidene fluoride (PVDF) as a binder, fully grinding, adding less N-methyl pyrrolidone (NMP), mixing to form uniform black paste slurry, coating the slurry on a copper foil current collector to serve as a test electrode, and assembling into an R2025 button cell by taking a metal lithium sheet as a contrast electrode, wherein an electrolytic liquid system is 1M LiPF6DEC (1:1), at a current density of 500mA/g, to test the cycling performance; the rate performance of the battery is tested under different current densities of 1000mA/g, 2000mA/g and the like. The test results obtained show that: under the current density of 500mA/g, after circulating for 300 circles, the specific capacity of 327mA/g can be kept, and after circulating for 2000 circles, the capacity of 87% can be kept; specific capacities of 318mAh/g and 289mAh/g can be respectively maintained under the discharge densities of 1000mA/g and 2000 mA/g. Compared with the example 1, the material prepared by the comparative example has no microcrystalline graphite, reduces the active sites of the graphite cathode coated with the asphalt carbon, and has poor cycle performance and rate capability.
Comparative example 2
10g of natural microcrystalline graphite and 5g of crystalline flake graphite are taken to be ball-milled and screened by a 100-mesh screen, the mass ratio of ball materials in the ball-milling process is 30:1, the rotating speed is 400rpm, the time is 6 hours, and the tap density of the obtained powder is 0.99g/cm3(ii) a Heating and stirring together with 6g of pitch liquid and a proper amount of ethanol in a closed container at 350 ℃, drying after 4 hours, washing the obtained mixed graphite carbon material with deionized water for 3 times, drying in vacuum at 80 ℃ for 6 hours, preparing 100ml of mixed acid solution with concentrated hydrochloric acid, concentrated hydrofluoric acid and deionized water in a ratio of 5:3:2, and mixing the mixed acid solutionPouring the acid solution into the asphalt-coated mixed graphite composite material, and heating and stirring by using a magnetic stirrer, wherein the stirring temperature is 80 ℃, and the treatment time of the mixed acid is 12 hours; filtering and washing for 3 times by using deionized water, and then performing ultrasonic oscillation cleaning by using 100ml of absolute ethyl alcohol to remove ash impurities remained in micropores, wherein the ultrasonic oscillation time is 2 hours; then filtering and washing the mixture for 3 times by using deionized water again; putting the mixture into an oven, and keeping the temperature at 60 ℃ for 6 hours. Putting the dried asphalt-coated mixed graphite composite material into a porcelain boat, introducing nitrogen into a quartz tube furnace for protection, pre-carbonizing at the low temperature of 450 ℃ for 4 hours, and then carbonizing at the high temperature of 900 ℃ for 4 hours; cooling to room temperature; thus obtaining the asphalt carbon-coated natural mixed graphite carbon negative electrode material.
Weighing 80 wt% of the asphalt carbon-coated natural mixed graphite material prepared in the embodiment, adding 10 wt% of Super P as a conductive agent, 10 wt% of polyvinylidene fluoride (PVDF) as a binder, fully grinding, adding less N-methyl pyrrolidone (NMP), mixing to form uniform black paste slurry, coating the slurry on a copper foil current collector to serve as a test electrode, and assembling a metal lithium sheet serving as a contrast electrode to form an R2025 button cell, wherein an electrolytic liquid system is 1M LiPF6DEC (1:1), at a current density of 500mA/g, to test the cycling performance; the rate performance of the battery is tested under different current densities of 1000mA/g, 2000mA/g and the like. The test results obtained show that: under the current density of 500mA/g, after circulating for 300 circles, the specific capacity of 368mA/g is kept, and after circulating for 2000 circles, the capacity of 84 percent can be kept; specific capacities of 267mAh/g and 190mAh/g can be respectively maintained under the discharge densities of 1000mA/g and 2000 mA/g. Compared with example 1, the material prepared by the comparative example has reduced porosity and a reduced microporous structure, and the cycle performance and rate performance of the material are both poor.
Comparative example 3
10g of natural microcrystalline graphite is taken and sieved by a 100-mesh sieve through ball milling, the mass ratio of balls to materials in the ball milling process is 30:1, the rotating speed is 400rpm, the time is 6 hours, and the tap density of the obtained powder is 0.98g/cm3(ii) a Putting the mixture and 10g of asphalt liquid into a porcelain boat, introducing nitrogen into a quartz tube furnace for protection, pre-carbonizing at the low temperature of 450 ℃ for 4 hours, and then addingCarbonizing at 900 deg.C for 4 hr; cooling to room temperature, washing the obtained microcrystalline graphite carbon material with deionized water for 3 times, carrying out vacuum drying at 80 ℃ for 6 hours, preparing 100ml of mixed acid solution by using concentrated hydrochloric acid, concentrated hydrofluoric acid and deionized water in a ratio of 5:3:2, pouring the mixed acid solution into the asphalt-coated microcrystalline graphite material, heating and stirring by using a magnetic stirrer at the stirring temperature of 80 ℃, and carrying out mixed acid treatment for 12 hours; filtering and washing for 3 times by using deionized water, and then performing ultrasonic oscillation cleaning by using 100ml of absolute ethyl alcohol to remove ash impurities remained in micropores, wherein the ultrasonic oscillation time is 2 hours; then filtering and washing the mixture for 3 times by using deionized water again; putting the mixture into an oven, and keeping the temperature at 60 ℃ for 6 hours; thus obtaining the asphalt carbon coated microcrystalline graphite carbon cathode material.
The asphalt carbon-coated microcrystalline graphite carbon negative electrode material prepared by the embodiment is used as a working electrode, lithium is used as a counter electrode, and an R2025 button cell is assembled and tested for cycle performance under the current density of 500 mA/g; the rate performance of the battery is tested under different current densities of 1000mA/g, 2000mA/g and the like. The obtained test results show that the lithium battery cathode prepared in the embodiment has good electrochemical performance: under the current density of 500mA/g, after circulating for 300 circles, the specific capacity of 335mA/g can be kept, and after circulating for 2000 circles, the capacity of 87% can be kept; under the discharge densities of 1000mA/g and 2000mA/g, the specific capacities of 320mAh/g and 299mAh/g can be respectively maintained. Compared with example 1, the material prepared by the comparative example has overlarge specific surface area, excessively high disorder degree, excessively rich microporous structure and poor cycle performance and rate capability.
Comparative example 4
Ball-milling 10g of natural microcrystalline graphite and 10g of crystalline flake graphite, sieving the materials through a 100-mesh sieve, wherein the mass ratio of the materials in the ball-milling process is 30:1, the rotating speed is 400rpm, the time is 6 hours, and the tap density of the obtained powder is 1.00g/cm3(ii) a Putting the dried asphalt-coated microcrystalline graphite composite material into a porcelain boat, introducing nitrogen into a quartz tube furnace for protection, and carbonizing at 900 ℃ for 6 hours; after cooling to room temperature, the obtained microcrystalline graphite carbon material is washed with deionized water3 times, drying in vacuum at 80 ℃ for 6 hours, preparing 100ml of mixed acid solution by concentrated hydrochloric acid, concentrated hydrofluoric acid and deionized water in a ratio of 5:4:1, pouring the mixed acid solution into the asphalt-coated mixed graphite composite material, heating and stirring by using a magnetic stirrer, wherein the stirring temperature is 80 ℃, and the mixed acid treatment time is 12 hours; filtering and washing for 3 times by using deionized water, and then performing ultrasonic oscillation cleaning by using 100ml of absolute ethyl alcohol to remove ash impurities remained in micropores, wherein the ultrasonic oscillation time is 2 hours; then filtering and washing the mixture for 3 times by using deionized water again; putting the mixture into an oven, and keeping the temperature at 60 ℃ for 6 hours; thus obtaining the asphalt carbon-coated natural mixed graphite carbon negative electrode material.
Weighing 80 wt% of the asphalt carbon-coated natural mixed graphite material prepared in the embodiment, adding 10 wt% of Super P as a conductive agent, 10 wt% of polyvinylidene fluoride (PVDF) as a binder, fully grinding, adding less N-methyl pyrrolidone (NMP), mixing to form uniform black paste slurry, coating the slurry on a copper foil current collector to serve as a test electrode, and assembling a metal lithium sheet serving as a contrast electrode to form an R2025 button cell, wherein an electrolytic liquid system is 1M LiPF6DEC (1:1), at a current density of 500mA/g, to test the cycling performance; the rate performance of the battery is tested under different current densities of 1000mA/g, 2000mA/g and the like. The obtained test results show that the lithium battery cathode prepared in the embodiment has good electrochemical performance: under the current density of 500mA/g, after circulating for 300 circles, the specific capacity of 331mA/g can still be kept, and after circulating for 2000 circles, the capacity of 85 percent can still be kept; under the discharge densities of 1000mA/g and 2000mA/g, the specific capacities of 312mAh/g and 292mAh/g can be respectively maintained. Compared with example 3, comparative example 4 lacks a low-temperature pre-carbonization process, the mixed graphite and the asphalt cannot be sufficiently fused and coated at a low temperature, the void ratio and the microporous structure are reduced, and the cycle performance and the rate capability of the mixed graphite are poor.
While the preferred embodiments of the present invention have been illustrated and described in detail, it is not intended that the scope of the appended claims be limited to the described embodiments.

Claims (6)

1. A preparation method of a natural mixed graphite material coated by asphalt carbon is characterized by comprising the following steps: the method comprises the following steps:
1) ball-milling and mixing microcrystalline graphite and crystalline flake graphite to obtain mixed graphite powder; the mass ratio of the microcrystalline graphite to the crystalline flake graphite is 1: 5-5: 1; ball-milling microcrystalline graphite and crystalline graphite powder until the granularity is below 100 meshes; the ball milling conditions are as follows: the ball material mass ratio is 20-40: 1, the rotating speed is 300-500 rpm, and the time is 2-12 h;
2) carrying out solvothermal reaction on the mixed graphite powder, asphalt liquid and an organic solvent to obtain a precursor material; the mass ratio of the mixed graphite powder to the asphalt liquid is 1: 10-10: 1; the organic solvent comprises at least one of formic acid, acetic acid, methanol, ethanol, ethylene glycol, isopropanol, butanol, acetonitrile, dichloromethane, chloroform, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone;
the conditions of the solvothermal reaction are as follows: the temperature is 80-400 ℃, and the time is 2-6 hours;
3) the precursor material is subjected to pre-carbonization and carbonization treatment, and then is purified by acid to obtain the material;
the precursor material is placed in a protective atmosphere, pre-carbonized at 350-750 ℃ for 2-12 hours, and carbonized at 800-1200 ℃ for 2-12 hours.
2. The method for preparing the asphalt carbon-coated natural mixed graphite material according to claim 1, wherein the method comprises the following steps: the acid purification process adopts HCl/HF mixed acid; the HCl/HF mixed acid is obtained by mixing concentrated hydrochloric acid, concentrated hydrofluoric acid and water according to the volume ratio of 0.8-1.5: 1: 0.5-1.
3. The method for preparing the asphalt-carbon-coated natural mixed graphite material according to claim 1 or 2, wherein: the acid purification process comprises the following steps: and (3) placing the carbonized product in HCl/HF mixed acid, and soaking for 12-36 hours at the temperature of 80-100 ℃.
4. A natural mixed graphite material coated by asphalt carbon is characterized in that: the preparation method of any one of claims 1 to 3.
5. The bituminous carbon-coated natural mixed graphite material according to claim 4, wherein: the asphalt carbon-coated natural mixed graphite material has a core-shell structure, the shell is an asphalt carbon layer, the core is natural mixed graphite, and the specific surface area of the asphalt carbon-coated natural mixed graphite material is 1-50 m2/g。
6. The use of the pitch carbon-coated natural mixed graphite material according to claim 4 or 5, wherein: the material is applied as a negative electrode material of a lithium ion battery.
CN201811477232.0A 2018-12-05 2018-12-05 Asphalt carbon-coated natural mixed graphite material and method for preparing lithium ion battery cathode by using same Active CN109599546B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201811477232.0A CN109599546B (en) 2018-12-05 2018-12-05 Asphalt carbon-coated natural mixed graphite material and method for preparing lithium ion battery cathode by using same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201811477232.0A CN109599546B (en) 2018-12-05 2018-12-05 Asphalt carbon-coated natural mixed graphite material and method for preparing lithium ion battery cathode by using same

Publications (2)

Publication Number Publication Date
CN109599546A CN109599546A (en) 2019-04-09
CN109599546B true CN109599546B (en) 2020-12-04

Family

ID=65961121

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201811477232.0A Active CN109599546B (en) 2018-12-05 2018-12-05 Asphalt carbon-coated natural mixed graphite material and method for preparing lithium ion battery cathode by using same

Country Status (1)

Country Link
CN (1) CN109599546B (en)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110061237A (en) * 2019-04-25 2019-07-26 广东工业大学 A kind of amorphous carbon cell negative electrode material and its preparation method and application
KR20210040810A (en) * 2019-10-04 2021-04-14 주식회사 엘지화학 Globular Carbon type Anode Active Material, Method for preparing the same, Anode Comprising the same, and Lithium Secondary Battery Comprising the same
CN111354944B (en) * 2020-03-20 2021-03-26 宁德新能源科技有限公司 Negative electrode active material, and electrochemical device and electronic device using same
CN112670464B (en) * 2020-04-21 2022-02-18 宁波杉杉新材料科技有限公司 Graphite negative electrode material, lithium ion battery and preparation method and application of graphite negative electrode material
CN111613785A (en) * 2020-05-28 2020-09-01 贝特瑞新材料集团股份有限公司 Composite coated negative electrode material, preparation method thereof and lithium ion battery
CN112038603A (en) * 2020-09-03 2020-12-04 青海凯金新能源材料有限公司 Graphite negative electrode material and processing technology thereof
CN114373925A (en) * 2020-10-14 2022-04-19 天津工业大学 Preparation method and application of oxidation modified amorphous carbon material
CN114520328B (en) * 2020-11-20 2023-10-10 中国科学院大连化学物理研究所 Lithium ion battery negative electrode material, preparation method thereof, negative electrode and battery
CN112573517A (en) * 2020-12-03 2021-03-30 铜仁学院 Preparation method of asphalt-based hard carbon-coated natural graphite negative electrode material
CN113571684B (en) * 2021-09-26 2021-12-28 河南电池研究院有限公司 Aluminum-carbon double-coated natural graphite negative electrode material for lithium ion battery and preparation method thereof
CN114291814B (en) * 2021-12-24 2024-04-16 东北师范大学 Graphite negative electrode material and preparation method and application thereof
CN114843648A (en) * 2022-05-13 2022-08-02 南京工业大学 Regeneration method of waste graphite cathode material of lithium ion battery
CN117142457B (en) * 2023-11-01 2024-01-12 东北大学 Preparation method of asphalt-based hard carbon material and application of asphalt-based hard carbon material in negative electrode of sodium ion battery
CN117658103B (en) * 2023-12-07 2024-09-20 湖南科舰能源发展有限公司 Preparation method of soft carbon negative electrode material for lithium battery

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1885598A (en) * 2006-07-10 2006-12-27 深圳市贝特瑞电子材料有限公司 Composite carbon negative electrode material of lithium ion power battery and its preparation method
CN102659091A (en) * 2012-05-03 2012-09-12 天津市贝特瑞新能源科技有限公司 High-capacity graphite material and preparation method as well as application thereof
CN106532051A (en) * 2015-09-29 2017-03-22 宁波杉杉新材料科技有限公司 Method for preparing negative electrode material of power lithium-ion battery by using natural graphite
CN107403917A (en) * 2017-07-25 2017-11-28 中南钻石有限公司 A kind of preparation of asphalt grout and the method that graphite cathode is prepared using the slurry
CN108054024A (en) * 2017-12-22 2018-05-18 湖南工业大学 A kind of application of mixed expanded graphite as lithium-ion capacitor negative material

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103094536A (en) * 2013-02-05 2013-05-08 新乡远东电子科技有限公司 High-capacity lithium ion secondary battery cathode carbon material

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1885598A (en) * 2006-07-10 2006-12-27 深圳市贝特瑞电子材料有限公司 Composite carbon negative electrode material of lithium ion power battery and its preparation method
CN102659091A (en) * 2012-05-03 2012-09-12 天津市贝特瑞新能源科技有限公司 High-capacity graphite material and preparation method as well as application thereof
CN106532051A (en) * 2015-09-29 2017-03-22 宁波杉杉新材料科技有限公司 Method for preparing negative electrode material of power lithium-ion battery by using natural graphite
CN107403917A (en) * 2017-07-25 2017-11-28 中南钻石有限公司 A kind of preparation of asphalt grout and the method that graphite cathode is prepared using the slurry
CN108054024A (en) * 2017-12-22 2018-05-18 湖南工业大学 A kind of application of mixed expanded graphite as lithium-ion capacitor negative material

Also Published As

Publication number Publication date
CN109599546A (en) 2019-04-09

Similar Documents

Publication Publication Date Title
CN109599546B (en) Asphalt carbon-coated natural mixed graphite material and method for preparing lithium ion battery cathode by using same
CN111333064B (en) High-performance lithium ion battery graphite negative electrode material and preparation method thereof
CN109273680B (en) Porous silicon-carbon negative electrode material, preparation method thereof and lithium ion battery
CN106941167B (en) Porous composite negative electrode material of lithium ion battery and preparation method thereof
CN109004205B (en) Preparation method of lithium-sulfur battery positive electrode material
WO2022121136A1 (en) Artificial graphite negative electrode material for high-rate lithium ion battery and preparation method therefor
CN113044827A (en) Nano carbon material composite biomass hard carbon electrode material and preparation method and application thereof
CN107946553B (en) High-graphitization three-dimensional carbon nanotube graphene composite material and preparation and application thereof
CN114188511B (en) Nitrogen-doped carbon-coated graphite composite material and preparation method and application thereof
CN109616640B (en) Modified microcrystalline graphite, preparation thereof and application thereof in lithium ion battery
CN102916178A (en) Preparation method of carbon cladding modified lithium manganate anode material
CN115706230B (en) Composite graphite negative electrode material, negative electrode plate and lithium ion battery
CN114430038A (en) Fast-charging hard carbon negative electrode material and preparation method and application thereof
CN117658107A (en) Bamboo-based hard carbon negative electrode material, preparation method thereof and sodium ion battery negative electrode
CN110395728B (en) Preparation method of porous carbon sphere negative electrode material for lithium battery
CN115947336A (en) Sodium ion battery and modified hard carbon cathode thereof
CN117239101A (en) Nitrogen-doped carbon nanotube-coated polyanion type positive electrode material and preparation method thereof
Li et al. Preparation of biochar from different biomasses and their application in the Li-S battery
CN114388788A (en) Preparation method of flexible spinning hollow carbon self-supporting electrode
CN116885144B (en) Silicon-carbon composite material for lithium battery cathode material and preparation method thereof
CN113998700A (en) Method for preparing Si/SiC @ C anode material by using micro silicon powder as raw material
CN112397701A (en) Rice husk-based silicon oxide/carbon composite negative electrode material and preparation method and application thereof
CN109256561B (en) Hard carbon negative electrode material, manufacturing method thereof and method for manufacturing battery by using hard carbon negative electrode material
CN114590808B (en) Preparation method of three-dimensional hierarchical porous spherical active carbon material
TWI434453B (en) Modification of artificial graphite as a lithium battery anode material preparation method

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant
TR01 Transfer of patent right
TR01 Transfer of patent right

Effective date of registration: 20220510

Address after: 537000 No. 267, Renmin East Road, Yulin City, Guangxi Zhuang Autonomous Region

Patentee after: Guangxi Chenyu New Material Co.,Ltd.

Address before: Yuelu District City, Hunan province 410083 Changsha Lushan Road No. 932

Patentee before: CENTRAL SOUTH University