CN112125294B - Coal-based silicon-carbon composite negative electrode material and preparation method thereof - Google Patents

Coal-based silicon-carbon composite negative electrode material and preparation method thereof Download PDF

Info

Publication number
CN112125294B
CN112125294B CN202010997901.8A CN202010997901A CN112125294B CN 112125294 B CN112125294 B CN 112125294B CN 202010997901 A CN202010997901 A CN 202010997901A CN 112125294 B CN112125294 B CN 112125294B
Authority
CN
China
Prior art keywords
coal
porous
carbon
negative electrode
silicon
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
CN202010997901.8A
Other languages
Chinese (zh)
Other versions
CN112125294A (en
Inventor
王夏阳
曹新龙
田占元
张长安
曹国林
白杨芝
薛孟尧
胥鑫
霍林智
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.)
Shaanxi Coal and Chemical Technology Institute Co Ltd
Original Assignee
Shaanxi Coal and Chemical Technology Institute Co Ltd
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 Shaanxi Coal and Chemical Technology Institute Co Ltd filed Critical Shaanxi Coal and Chemical Technology Institute Co Ltd
Priority to CN202010997901.8A priority Critical patent/CN112125294B/en
Publication of CN112125294A publication Critical patent/CN112125294A/en
Application granted granted Critical
Publication of CN112125294B publication Critical patent/CN112125294B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

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
    • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/02—Silicon
    • C01B33/021—Preparation
    • C01B33/023—Preparation by reduction of silica or free silica-containing material
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/02—Silicon
    • C01B33/021—Preparation
    • C01B33/023—Preparation by reduction of silica or free silica-containing material
    • C01B33/025—Preparation by reduction of silica or free silica-containing material with carbon or a solid carbonaceous material, i.e. carbo-thermal process
    • 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
    • H01M4/362—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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
    • 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
    • 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
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Landscapes

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

Abstract

The invention discloses a coal-based silicon-carbon composite negative electrode material and a preparation method thereof, amorphous porous carbon obtained by low-temperature carbonization of anthracite by taking anthracite as a carbon source and diatomite as a silicon source can promote ordered deintercalation of lithium ions, improve the specific capacity of the material, realize the reserved expansion space of the porous structure of the diatomite, effectively improve the expansion problem of a silicon-based negative electrode, and simultaneously purify the diatomite to obtain porous SiO2Thermal reduction is carried out with metallic lithium to realize SiOxThe preparation and the pre-lithium treatment of the coal-based silicon-carbon composite negative electrode material further improve the cycle stability of the negative electrode material; the invention discloses a coal-based silicon-carbon composite negative electrode material and a preparation method thereof, aiming at solving the problem of expansion of the silicon-based negative electrode material, improving the first coulombic effect of the material on the basis of not reducing the conductivity, simultaneously reducing the preparation cost of the material by taking anthracite as a carbon source and diatomite as a silicon source, and being beneficial to realizing the industrial production of the silicon-based negative electrode material.

Description

Coal-based silicon-carbon composite negative electrode material and preparation method thereof
Technical Field
The invention belongs to the technical field of lithium ion battery cathode materials, and particularly relates to a coal-based silicon-carbon composite cathode material and a preparation method thereof.
Background
The improvement of energy density is always the main melody of the technical development of the lithium ion battery, and one is to optimize the battery structure, such as the concepts of Ningde time CPT technology, BYD 'blade battery' and the like; another effort is to break through the technical barriers of high capacity materials, which is also the mainstream approach currently taken by battery manufacturers. The anode and cathode materials are the key for improving the energy density of the lithium ion battery, although the anode material occupies a core position in the battery, the theoretical gram capacity of the graphite cathode material is 372mAh/g, which becomes a limiting condition for further improving the energy of the lithium ion battery, the theoretical gram capacity of silicon as the cathode material of the lithium battery is 4200mAh/g, and the silicon-based composite material has higher specific capacity and lower de-intercalation lithium potential and is considered as the most potential new generation cathode material of the lithium battery.
In order to improve the cycling stability of the silicon-based negative electrode material, the silicon material is generally nanocrystallized or compounded with a carbon material, the requirements on a carbon source and a silicon source material are high, and the manufacturing cost is high.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a coal-based silicon-carbon composite negative electrode material and a preparation method thereof, aiming at solving the expansion of the silicon-based negative electrode material, improving the first coulombic effect of the material on the basis of not reducing the conductivity, reducing the preparation cost of the material by taking anthracite as a carbon source and diatomite as a silicon source and being beneficial to realizing the industrial production of the silicon-based negative electrode material.
In order to achieve the purpose, the invention provides the following technical scheme: a preparation method of a coal-based silicon-carbon composite negative electrode material comprises the following steps:
firstly, pretreating anthracite to obtain amorphous porous carbon, and pretreating diatomite to obtain purified porous SiO2 powder;
step two, mixing lithium powder with the porous SiO2 powder obtained in the step one, and reacting in a protective atmosphere to obtain a porous SiOx/Si/Li2SiOy compound;
dispersing a dispersing agent, the amorphous porous carbon obtained in the step one and the porous SiOx/Si/Li2SiOy compound obtained in the step two in a solvent, and then grinding to obtain precursor slurry;
and step four, performing spray drying, fusion and granulation on the precursor slurry obtained in the step three, and then performing high-temperature carbonization and gas phase coating to obtain the coal-based silicon-carbon composite negative electrode material.
Further, in the step one, the anthracite coal pretreatment comprises the following specific steps: firstly, carrying out first heat treatment on anthracite, carrying out second heat treatment after crushing, acid washing, water washing or alcohol washing and drying on the anthracite subjected to the first heat treatment, and then crushing to obtain amorphous porous carbon; the diatomite pretreatment comprises the following specific steps: and (3) carrying out third heat treatment on the diatomite, crushing, acid washing, water washing, drying and crushing to obtain purified porous SiO2 powder.
Further, sulfuric acid with the mass fraction of more than 70% is adopted during acid cleaning, and the acid cleaning is carried out for 1h-4h under the conditions that the temperature is 70-100 ℃, and the liquid-solid ratio is (2-5): 1; the acid washing and the water washing or the alcohol washing are alternately carried out for a plurality of times until the pH value of the washing liquid is between 6 and 8; the first heat treatment temperature is 600-800 ℃, the second heat treatment temperature is 800-1200 ℃, the third heat treatment temperature is 400-750 ℃, and the heat preservation time of the first heat treatment, the second heat treatment and the third heat treatment is 1-4 h.
Further, in the second step, the mass ratio of the lithium powder to the porous SiO2 powder is 1 (0.5-3), and the lithium powder and the porous SiO2 powder are thermally reduced under the reaction condition that the temperature is 600-900 ℃.
Further, in the third step, the mass ratio of the porous SiOx/Si/Li2SiOy compound to the amorphous porous carbon is 1 (1-4); the solvent is at least one of alcohols, ketones, alkanes and lipids, and the grinding adopts wet grinding for 1-12 h.
Further, in the fourth step, the high-temperature carbonization is carried out by two-stage temperature rise under inert atmosphere, the temperature is firstly preserved for 1-4h at the temperature of 200-450 ℃, and then is raised to the temperature of 750-950 ℃, and the temperature is preserved for 1-6 h.
Further, the gas phase coating is to introduce organic carbon source gas at the temperature of 750-950 ℃ for reaction for 1-6 h; the organic carbon source gas is at least one of methane, acetylene and natural gas or the combination of at least one of methane, acetylene and natural gas and hydrogen.
And further, crushing, screening and demagnetizing the coal-based silicon-carbon composite negative electrode material obtained in the fourth step.
Further, the composite material comprises an inner core (1) and an outer shell (3) and a porous intermediate layer (2) between the inner core (1) and the outer shell (3), so that the inner core (1) is amorphous porous carbon, and the porous intermediate layer (2) is a porous SiOx/Si/Li2SiOy composite.
The invention also provides a coal-based silicon-carbon composite negative electrode material, amorphous porous carbon is obtained by low-temperature carbonization of anthracite, the porous intermediate layer (2) takes diatomite as a silicon source, and the shell (3) is a carbon coating layer.
Compared with the prior art, the invention has at least the following beneficial effects:
according to the invention, anthracite is used as a carbon source, diatomite is used as a silicon source, and amorphous porous carbon obtained by low-temperature carbonization of the anthracite can promote ordered deintercalation of lithium ions and improve the specific capacity of the material; the invention adopts anthracite as carbon source, and provides the technical proposal of taking graphite as carbon source in the prior art, because the price of the anthracite is far lower than that of the graphite, the cost of the raw materials is reduced by adopting the carbon source of the anthracite crops; furthermore, the invention realizes the reserved expansion space by utilizing the porous structure of the diatomite, thereby effectively improving the expansion problem of the silicon-based cathode; the diatomite is subjected to a series of treatments to obtain porous SiO2Obtaining porous SiO2The reaction is carried out with metallic lithium which is a reducing agent, and the reaction degree is reasonableControl, under the condition of not introducing other impurities, the SiO is realizedxThe preparation and the pre-lithium treatment of the coal-based silicon-carbon composite negative electrode material further improve the cycle stability of the negative electrode material; the invention adopts diatomite to purify and obtain porous SiO2Further reducing the cost of raw materials.
Furthermore, the coal-based silicon-carbon composite negative electrode material obtained by the invention is subjected to high-temperature carbonization before gas-phase carbon coating, impurities in a carbon matrix and reaction substances added in the preparation process can be carbonized through the high-temperature carbonization, and the physical coating structure of the core and the shell can be more stable; the invention adopts the gas phase to coat the porous intermediate layer and the carbon coating layer, which is beneficial to improving the mechanical processing performance, the conductivity and the cycling stability of the material in the charging and discharging process.
The coal-based silicon-carbon composite negative electrode material comprises an inner core, a porous intermediate layer and a shell, wherein the inner core is amorphous porous carbon, so that lithium ion transmission is facilitated, and the specific capacity of the material is improved; the porous intermediate layer is porous SiOx/Si/Li2SiOyComposite of Si-SiOxThe specific capacity and the first effect of the negative electrode material can be improved, meanwhile, the Li is introduced into the negative electrode material to improve the cycling stability of the material, and the porous structure of the porous intermediate layer reserves an expansion space for the silicon material; the shell is a carbon coating layer, so that the machining performance and the conductivity of the material are improved.
Drawings
FIG. 1 is a schematic structural diagram of a coal-based silicon-carbon composite negative electrode material of the invention.
In the drawings: 1 is an inner core; 2 is a porous intermediate layer; and 3 is a shell.
Detailed Description
The invention is further described with reference to the following figures and detailed description.
The following examples are intended to further illustrate the present disclosure, but not to limit the scope of the claims.
Example 1
(1) Anthracite carbonization: the anthracite is kept at 600 ℃ for 4h, and then is crushed, acid-washed, water-washed and dried, wherein the acid-washed adopts sulfuric acid with the mass fraction larger than 70%, the acid-washed is carried out for 2h at 70 ℃ and the liquid-solid ratio of 5:1, the acid-washed and the water-washed are alternately carried out for many times, and the cleaning is stopped when the pH value of the washing liquid is between 6 and 8; and then drying, crushing, keeping the temperature at 800 ℃ for 4h, annealing and crushing to obtain the amorphous porous carbon.
(2) And (3) purifying the diatomite: keeping the temperature of the diatomite at 400 ℃ for 4h, and removing organic matters; then crushing, acid washing and water washing, wherein the acid washing adopts concentrated sulfuric acid with the mass fraction larger than 70%, the acid washing is carried out for 2 hours at the temperature of 70 ℃ and the liquid-solid ratio of 5:1, the acid washing and the water washing are alternately carried out for many times, and the cleaning is stopped when the pH value of the washing liquid is between 6 and 8; then drying and crushing are carried out to obtain purified porous SiO2And (3) powder.
(3)SiOx/Si/Li2SiOyPreparing a compound: lithium powder and porous SiO with the mass ratio of 1:0.52The powders are evenly mixed and are subjected to thermal reduction reaction at 750 ℃ in the nitrogen atmosphere to obtain porous SiOx/Si/Li2SiOyComposite, SiOx/Si/Li obtained by incomplete reaction of lithium powder and porous SiO2 powder2In the SiOy compound, x is more than or equal to 1 and less than or equal to 2, and y is more than or equal to 3 and less than or equal to 5.
(4) Preparing precursor slurry: porous SiOx/Si/Li2SiOyAdding the composite, the amorphous porous carbon and the dispersing agent into acetone respectively, and carrying out wet grinding for 6h to obtain uniformly dispersed precursor slurry, wherein the porous SiO isx/Si/Li2SiOyThe mass ratio of the composite to the amorphous porous carbon is 1: 4.
(5) Preparing a negative electrode material: carrying out spray drying, fusion and granulation on the obtained precursor slurry, then carrying out high-temperature carbonization, firstly, keeping the temperature at 450 ℃ for 1h, then, raising the temperature to 750 ℃, and keeping the temperature for 6 h; and then carrying out gas phase coating, introducing mixed gas of methane and acetylene at the temperature of 750 ℃, and reacting for 6 hours to obtain the coal-based silicon-carbon composite cathode material.
Example 2
(1) Anthracite carbonization: the anthracite is kept at 800 ℃ for 1h, and then is crushed, acid-washed, alcohol-washed and dried, wherein the acid-washed adopts sulfuric acid with the mass fraction larger than 70%, the acid-washed is carried out for 1h at 100 ℃ and the liquid-solid ratio of 2:1, the acid-washed and the alcohol-washed are carried out alternately, and the cleaning is stopped when the pH value of the washing liquid is between 6 and 8; and then drying, crushing, keeping the temperature at 1200 ℃ for 1h, annealing and crushing to obtain the amorphous porous carbon.
(2) And (3) purifying the diatomite: keeping the temperature of the diatomite at 750 ℃ for 1h, and removing organic matters; then crushing, acid washing and water washing, wherein the acid washing adopts sulfuric acid with the mass fraction of more than 70%, the acid washing is carried out for 1h at the temperature of 100 ℃ and the liquid-solid ratio of 2:1, the acid washing and the water washing are alternated, and the cleaning is stopped when the pH value of the washing liquid is between 6 and 8; then drying and crushing are carried out to obtain purified porous SiO2And (3) powder.
(3)SiOx/Si/Li2SiOyPreparing a compound: lithium powder and porous SiO with the mass ratio of 1:32The powders are evenly mixed and are subjected to thermal reduction reaction at 600 ℃ in the nitrogen atmosphere to obtain porous SiOx/Si/Li2SiOyComposite, SiOx/Si/Li obtained by incomplete reaction of lithium powder and porous SiO2 powder2In the SiOy compound, x is more than or equal to 1 and less than or equal to 2, and y is more than or equal to 3 and less than or equal to 5.
(4) Preparing precursor slurry: porous SiOx/Si/Li2SiOyAdding the compound, the amorphous porous carbon and soft carbon compound and the dispersing agent into a mixture of isopropanol and acetone for wet grinding for 12h to obtain uniformly dispersed precursor slurry, wherein porous SiO isx/Si/Li2SiOyThe mass ratio of the composite to the amorphous porous carbon is 1: 1.
(5) Preparing a negative electrode material: carrying out spray drying, fusion and granulation on the obtained precursor slurry, then carrying out high-temperature carbonization, firstly, keeping the temperature at 200 ℃ for 4h, then, heating to 950 ℃, and keeping the temperature for 1 h; then carrying out gas phase coating, introducing acetylene and hydrogen mixed gas at 950 ℃, and reacting for 2h to obtain the coal-based silicon-carbon composite cathode material.
Example 3
(1) Anthracite carbonization: the anthracite is kept at 700 ℃ for 2h, and then is crushed, acid-washed, alcohol-washed and dried, wherein the acid-washed adopts sulfuric acid with the mass fraction larger than 70%, the acid-washed is carried out for 4h at 85 ℃ and the liquid-solid ratio of 3:1, the acid-washed and the alcohol-washed are alternately carried out for a plurality of times, and the cleaning is stopped when the pH value of the washing liquid is between 6 and 8; and then drying, crushing, keeping the temperature for 2 hours at 1000 ℃, annealing and crushing to obtain the amorphous porous carbon.
(2) And (3) purifying the diatomite: keeping the temperature of the diatomite at 600 ℃ for 2h, and removing organic matters; then crushing, acid washing and water washing, wherein the acid washing adopts concentrated sulfuric acid with the mass fraction of more than 70%, the acid washing is carried out for 4 hours at the temperature of 85 ℃ and the liquid-solid ratio of 3:1, the acid washing and the water washing are alternately carried out for multiple times, and the cleaning is stopped when the pH value of the washing liquid is between 6 and 8; then drying and crushing are carried out to obtain purified porous SiO2And (3) powder.
(3)SiOx/Si/Li2SiOyPreparing a compound: lithium powder and porous SiO with the mass ratio of 1:12The powders are evenly mixed and are subjected to thermal reduction reaction at 900 ℃ in the nitrogen atmosphere to obtain porous SiOx/Si/Li2SiOyComposite, SiOx/Si/Li obtained by incomplete reaction of lithium powder and porous SiO2 powder2In the SiOy compound, x is more than or equal to 1 and less than or equal to 2, and y is more than or equal to 3 and less than or equal to 5.
(4) Preparing precursor slurry: porous SiOx/Si/Li2SiOyAdding the composite, the amorphous porous carbon and the dispersing agent into ethanol respectively to carry out wet grinding for 1h to obtain uniformly dispersed precursor slurry, wherein the porous SiO isx/Si/Li2SiOyThe mass ratio of the composite to the amorphous porous carbon is 1: 2.
(5) Preparing a negative electrode material: carrying out spray drying, fusion and granulation on the obtained precursor slurry, then carrying out high-temperature carbonization, firstly, keeping the temperature at 350 ℃ for 2h, then, heating to 850 ℃, and keeping the temperature for 2 h; and then carrying out gas phase coating, introducing mixed gas of natural gas and hydrogen at 850 ℃, reacting for 1h to obtain the coal-based silicon-carbon composite anode material, and crushing, screening and demagnetizing the obtained coal-based silicon-carbon composite anode material.
The silicon-based negative electrode material obtained in the above examples 1 to 3 is used as a negative electrode to be subjected to slurry preparation, coating and drying to obtain a negative electrode plate, and a metal lithium plate is used as a counter electrode to assemble a battery and perform electrochemical test, wherein the specific test method comprises the following steps: 1mol/L LiPF6And the electrolyte of/EC + DMC + EMC (V/V is 1:1:1) and a Celgard2400 diaphragm are assembled into the 2025 button cell. Adopts the Land of Wuhanjinnuo electronic Co LtdTesting the battery testing system at normal temperature, wherein the testing conditions are as follows: the first charge and discharge I is 0.1C, the cycle I is 0.1C, the voltage range is 0.005-2.0V, and the test results are shown in Table 1.
TABLE 1 test results of electrochemical properties of negative electrode materials
Technical index First reversible capacity/mAh.g-1 First effect/%) 200thCapacity retention ratio/%)
Example 1 1158 92.7 91.4
Example 2 1873 91.2 88.5
Example 3 1520 92.0 90.3
From the test results shown in table 1, it can be seen that anthracite coal subjected to low-temperature carbonization is used as a porous carbon matrix, diatomite is purified and used as a silicon source, and the prepared coal-based silicon-carbon composite negative electrode material shows good first specific capacity under different Si and C ratios, the first efficiency is above 90%, and the capacity retention rate of 100 cycles of 1C cycle is above 90%, which indicates that the silicon-carbon composite material of the present invention can still maintain good electrochemical performance under the condition of selecting low-quality raw materials.
As shown in FIG. 1, which is a specific structural schematic diagram of the coal-based silicon-carbon composite negative electrode material prepared by the invention, the inner core is amorphous porous carbon, the amorphous porous carbon is obtained by low-temperature carbonization of anthracite, and the porous intermediate layer is porous SiO prepared by taking diatomite as a silicon sourcex/Si/Li2SiOyThe shell of the composite is a carbon coating layer, and the structure of the coal-based silicon-carbon composite cathode material can well inhibit the expansion of a silicon-based material.

Claims (10)

1. The preparation method of the coal-based silicon-carbon composite negative electrode material is characterized by comprising the following steps of:
firstly, pretreating anthracite to obtain amorphous porous carbon, and pretreating diatomite to obtain purified porous SiO2 powder;
step two, mixing lithium powder with the porous SiO2 powder obtained in the step one, and reacting in a protective atmosphere to obtain a porous SiOx/Si/Li2SiOy compound;
dispersing a dispersing agent, the amorphous porous carbon obtained in the step one and the porous SiOx/Si/Li2SiOy compound obtained in the step two in a solvent, and then grinding to obtain precursor slurry;
and step four, performing spray drying, fusion and granulation on the precursor slurry obtained in the step three, and then performing high-temperature carbonization and gas phase coating to obtain the coal-based silicon-carbon composite negative electrode material.
2. The preparation method of the coal-based silicon-carbon composite anode material according to claim 1, wherein in the first step, the anthracite coal is pretreated by the following specific steps: firstly, carrying out first heat treatment on anthracite, carrying out second heat treatment after crushing, acid washing, water washing or alcohol washing and drying on the anthracite subjected to the first heat treatment, and then crushing to obtain amorphous porous carbon; the diatomite pretreatment comprises the following specific steps: and (3) carrying out third heat treatment on the diatomite, crushing, acid washing, water washing, drying and crushing to obtain purified porous SiO2 powder.
3. The preparation method of the coal-based silicon-carbon composite anode material according to claim 2, characterized in that sulfuric acid with the mass fraction of more than 70% is adopted during acid washing, and the acid washing is carried out for 1h to 4h at the temperature of 70 ℃ to 100 ℃ and the liquid-solid ratio of (2-5): 1; the acid washing and the water washing or the alcohol washing are alternately carried out for a plurality of times until the pH value of the washing liquid is between 6 and 8; the first heat treatment temperature is 600-800 ℃, the second heat treatment temperature is 800-1200 ℃, the third heat treatment temperature is 400-750 ℃, and the heat preservation time of the first heat treatment, the second heat treatment and the third heat treatment is 1-4 h.
4. The preparation method of the coal-based silicon-carbon composite negative electrode material as claimed in claim 1, wherein in the second step, the mass ratio of the lithium powder to the porous SiO2 powder is 1 (0.5-3), and the lithium powder and the porous SiO2 powder are thermally reduced under the reaction condition that the temperature is 600-900 ℃.
5. The method for preparing the coal-based silicon-carbon composite anode material according to claim 1, wherein in the third step, the mass ratio of the porous SiOx/Si/Li2SiOy composite to the amorphous porous carbon is 1 (1-4); the solvent is at least one of alcohols, ketones, alkanes and lipids, and the grinding adopts wet grinding for 1-12 h.
6. The method for preparing the coal-based silicon-carbon composite anode material as claimed in claim 1, wherein in the fourth step, the high temperature carbonization is a two-stage temperature rise under an inert atmosphere, and the temperature is first maintained at 200-450 ℃ for 1-4h, then increased to 750-950 ℃ and maintained for 1-6 h.
7. The method for preparing a coal-based silicon-carbon composite anode material as claimed in claim 1, wherein the gas phase coating is performed by introducing an organic carbon source gas at 750-950 ℃ for reaction for 1-6 h; the organic carbon source gas is at least one of methane, acetylene and natural gas or the combination of at least one of methane, acetylene and natural gas and hydrogen.
8. The preparation method of the coal-based silicon-carbon composite negative electrode material according to claim 1, wherein the coal-based silicon-carbon composite negative electrode material obtained in the fourth step is crushed, sieved and demagnetized.
9. The coal-based silicon-carbon composite anode material obtained by the preparation method according to any one of claims 1 to 8, comprising an inner core (1) and an outer shell (3) and a porous intermediate layer (2) between the inner core (1) and the outer shell (3), wherein the inner core (1) is amorphous porous carbon, and the porous intermediate layer (2) is a porous SiOx/Si/Li2SiOy composite.
10. The coal-based silicon-carbon composite negative electrode material as claimed in claim 9, wherein the amorphous porous carbon is obtained by low-temperature carbonization of anthracite, the porous intermediate layer (2) uses diatomite as a silicon source, and the shell (3) is a carbon coating layer.
CN202010997901.8A 2020-09-21 2020-09-21 Coal-based silicon-carbon composite negative electrode material and preparation method thereof Active CN112125294B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010997901.8A CN112125294B (en) 2020-09-21 2020-09-21 Coal-based silicon-carbon composite negative electrode material and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010997901.8A CN112125294B (en) 2020-09-21 2020-09-21 Coal-based silicon-carbon composite negative electrode material and preparation method thereof

Publications (2)

Publication Number Publication Date
CN112125294A CN112125294A (en) 2020-12-25
CN112125294B true CN112125294B (en) 2022-04-19

Family

ID=73842108

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010997901.8A Active CN112125294B (en) 2020-09-21 2020-09-21 Coal-based silicon-carbon composite negative electrode material and preparation method thereof

Country Status (1)

Country Link
CN (1) CN112125294B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113889605B (en) * 2021-09-11 2024-04-26 四川星耀新能源科技有限公司 Hard carbon-dopant coated anthracite composite anode material, preparation method thereof and lithium ion battery
CN115991473B (en) * 2022-12-12 2024-10-01 湖南钠方新能源科技有限责任公司 Modified amorphous material, preparation method thereof, negative plate and sodium ion battery
CN116462183A (en) * 2023-03-10 2023-07-21 中国科学院宁波材料技术与工程研究所 Soft carbon material with diatomite-like structure and preparation method and application thereof

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103022446A (en) * 2012-12-19 2013-04-03 深圳市贝特瑞新能源材料股份有限公司 Silicon oxide/carbon cathode material of lithium ion battery and preparation method of material
CN104979540A (en) * 2015-07-09 2015-10-14 东北师范大学 Preparation method and application of bicontinuous-structural nanocomposite material
CN108269979A (en) * 2017-12-28 2018-07-10 合肥国轩高科动力能源有限公司 Silicon monoxide/silicon/lithium metasilicate composite anode material and preparation method thereof
CN109835900A (en) * 2019-03-21 2019-06-04 哈尔滨工业大学 A kind of preparation method of the coal base porous carbon based on potassium carbonate cyclic activation and the preparation method of biomass-based porous carbon

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101710617B (en) * 2009-05-12 2011-10-26 大连丽昌新材料有限公司 High-energy silicon-carbon composite negative electrode material for lithium ion battery and manufacturing process thereof
CN102208636B (en) * 2011-05-12 2013-07-03 北京科技大学 Method for preparing porous silicon/carbon composite material by using diatomite as raw material and application
CN102903896B (en) * 2012-10-22 2015-07-29 深圳清华大学研究院 For the silicon-carbon composite cathode material of lithium ion battery, its preparation method and application
CN103337613B (en) * 2013-07-04 2015-08-12 奇瑞汽车股份有限公司 A kind of Si-C composite material and preparation method thereof, lithium ion battery
US20150162617A1 (en) * 2013-12-09 2015-06-11 Nano And Advanced Materials Institute Limited Si@C core/shell Nanomaterials for High Performance Anode of Lithium Ion Batteries
CN103730644B (en) * 2013-12-12 2016-03-09 天津巴莫科技股份有限公司 Silicon-silicon oxide-carbon composite negative pole material of lithium ion battery preparation method
CN105680026B (en) * 2016-04-21 2019-07-09 苏州协鑫集成科技工业应用研究院有限公司 Carbon composite and preparation method thereof and battery
JP2018152161A (en) * 2017-03-09 2018-09-27 株式会社豊田自動織機 Negative electrode material
CN111362269A (en) * 2020-03-09 2020-07-03 上海电气集团股份有限公司 Preparation method of SEI (solid electrolyte interphase) film of lithium ion battery cathode, lithium ion battery cathode material and application of lithium ion battery cathode material

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103022446A (en) * 2012-12-19 2013-04-03 深圳市贝特瑞新能源材料股份有限公司 Silicon oxide/carbon cathode material of lithium ion battery and preparation method of material
CN104979540A (en) * 2015-07-09 2015-10-14 东北师范大学 Preparation method and application of bicontinuous-structural nanocomposite material
CN108269979A (en) * 2017-12-28 2018-07-10 合肥国轩高科动力能源有限公司 Silicon monoxide/silicon/lithium metasilicate composite anode material and preparation method thereof
CN109835900A (en) * 2019-03-21 2019-06-04 哈尔滨工业大学 A kind of preparation method of the coal base porous carbon based on potassium carbonate cyclic activation and the preparation method of biomass-based porous carbon

Also Published As

Publication number Publication date
CN112125294A (en) 2020-12-25

Similar Documents

Publication Publication Date Title
CN112125294B (en) Coal-based silicon-carbon composite negative electrode material and preparation method thereof
CN109148847B (en) Boron-doped modified hard carbon-coated negative electrode material with high rate performance and liquid-phase preparation method thereof
CN104009210B (en) A kind of porous silicon/carbon composite material, Preparation method and use
CN112421048A (en) Method for preparing graphite-coated nano-silicon lithium battery negative electrode material at low cost
CN112234197B (en) Amorphous carbon-silicon-carbon nanofiber-graphite composite material and preparation method and application thereof
CN112652758B (en) Silicon oxide/carbon microsphere composite negative electrode material for lithium ion battery and preparation method thereof
CN102593415A (en) Preparation method for positive electrode of lithium ion battery
CN114639809B (en) Composite hard carbon negative electrode material, preparation method and application
CN102887504B (en) A kind of preparation method of carbon material for lithium ion battery cathode
CN114388738B (en) Silicon-based anode material and preparation method and application thereof
CN109698337B (en) Sulfur-spore carbon/niobium carbide composite electrode material and preparation method and application thereof
CN107910540B (en) Preparation method of carbon-silicon negative electrode material and lithium ion battery
CN112142060B (en) Coal-based silicon-carbon composite negative electrode material and preparation method thereof
CN117855434A (en) Pre-magnesium silicon oxide anode material of lithium ion battery and preparation method thereof
CN106684367B (en) Low-temperature petroleum coke negative electrode material coated with nitrogen-containing polymer pyrolytic carbon and preparation method thereof
CN110797516B (en) C-coated SiO-SnSiO4-Si super-particle material and preparation method and application thereof
CN112133898B (en) Silicon-based negative electrode material and preparation method thereof
CN112397701A (en) Rice husk-based silicon oxide/carbon composite negative electrode material and preparation method and application thereof
CN111554928A (en) Graphene-based composite material and preparation method and application thereof
CN114864888B (en) Lithium difluoro oxalate borate doped coated SiO/C composite material and preparation method and application thereof
CN111348685B (en) Graphene-based composite material and preparation method and application thereof
CN109860527B (en) Carbon-based composite material for preparing lithium battery cathode and preparation method thereof
CN115472832A (en) Method for preparing high-capacity lithium battery negative electrode material from natural graphite spherical tailings
CN110676444A (en) Method for preparing silicon/carbon nanotube composite material in situ by one-pot method
EP4439702A1 (en) Negative electrode material, electrochemical device and electronic device

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