CN117154043A - Negative electrode material and preparation method and application thereof - Google Patents

Negative electrode material and preparation method and application thereof Download PDF

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Publication number
CN117154043A
CN117154043A CN202311123964.0A CN202311123964A CN117154043A CN 117154043 A CN117154043 A CN 117154043A CN 202311123964 A CN202311123964 A CN 202311123964A CN 117154043 A CN117154043 A CN 117154043A
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negative electrode
fraction
colloid
coating
aromatic
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张�浩
金钊
唐文
刘娇
江柯成
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Jiangsu Zenio New Energy Battery Technologies Co Ltd
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Jiangsu Zenio New Energy Battery Technologies Co Ltd
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    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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

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

Abstract

The invention relates to a negative electrode material, and a preparation method and application thereof. The negative electrode material is of a core-shell structure, a negative electrode active material is taken as an inner core, and a coating layer coated on the surface of the negative electrode active material is taken as a shell layer; the coating agent in the coating layer comprises a saturation fraction Sa1, an aromatic fraction Ar1, colloid Re1 and asphaltene As1; the contents of the saturation fraction Sa1, the aromatic fraction Ar1, the colloid Re1 and the asphaltene As1 are As follows, and the contents are counted in percentage by mass: w is more than or equal to 0.02 Sa1 ≤0.18，0.05≤W Ar1 ≤0.31，0.32≤W Re1 Less than or equal to 0.62, the balance of W As1 Is contained in the composition; w (W) Sa1 +W Ar1 +W Re1 +W As1 =1; the molecular weight of the components in the coating agent is 50-10000. The invention provides a preparation method of a negative electrode coating material by optimizing and customizing coating reagents, mainly by optimizing components of a saturated component Sa1, an aromatic component Ar1 and a colloid Re1, so that the prepared negative electrode coating material has good consistency, good charge-discharge multiplying power and cycle life, and relatively low cost.

Description

Negative electrode material and preparation method and application thereof
Technical Field
The invention relates to the technical field of batteries, in particular to a negative electrode material and a preparation method and application thereof.
Background
Along with the popularization of new energy automobiles, lithium ion batteries are widely applied to electric automobiles, and how to improve the charging capacity and the cruising ability of the lithium ion batteries is a key to winning market competition. At present, the main stream lithium ion battery cathode material is a graphite material, and the improvement of the quick charge performance of the graphite cathode material has an important influence on the improvement of the charge capacity of the lithium ion battery. The current graphite negative electrode material generally improves the quick charge capacity by a coating method, and coats a layer of soft carbon or hard carbon material with an amorphous structure on the surface of graphite to obtain a core-shell structure which takes graphite as an inner core and takes the soft carbon or hard carbon material with the amorphous structure as an outer shell, so that the interface impedance of the graphite negative electrode material is reduced, and the charge performance is improved. The raw materials of the coating reagent are the conventional coating reagent, and the conventional coating reagent is a typical mixture, has complex components and wide source range, and is prepared from crude oil or coal in different production places, so that the consistency of components is difficult to ensure and the consistency of the structure after the subsequent coating process and the coating carbonization is difficult to control. In view of this, in order to ensure the uniformity and stability of the coating materials, it is necessary to provide a solution to the above-mentioned problems.
The conventional coating reagent is asphalt and tar type coating reagent, the components of the asphalt and tar type coating reagent are complex, the asphalt and tar type coating reagent consists of hydrocarbons and aromatic compounds with different molecular weights, wherein the light components with relatively smaller molecular weights have good fluidity, the coating wettability of the graphite inner core is strong, the good fluidity is favorable for forming uniform surface coating layers in the coating process, but the content of fixed carbon is low, after coating, the yield of the fixed carbon of a formed coating layer is low after high-temperature carbonization, the volatilization of the coating reagent is obvious, the coating layer is too thin, the graphite material is difficult to obtain a complete coating thickness, the part with larger molecular weight is high in the content of the fixed carbon, the yield of the fixed carbon after carbonization is high, and the main structural part of the amorphous carbon layer coated on the graphite surface after high-temperature carbonization is poor in fluidity of the components, so that the coating layer has poor wettability to the graphite inner core, the uniformity of the coating is poor, and the uniform and stable coating layer is difficult to obtain.
As described above, the pitch and tar compound components are complex, and are divided into components, and the components having a small molecular weight are defined from the molecular weight level, and are generally defined As a saturated component Sa1 and an aromatic component Ar1 due to their high saturation, and the components having a large molecular weight are generally referred to As colloidal Re1, and the components having the largest molecular weight are generally referred to As asphaltenes As1.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to overcome the common coating agent such as tar and other mixtures in the prior art, wherein the saturated fraction and the aromatic fraction with small molecular weight have low boiling points generally, and the high-temperature distillation is easy to volatilize.
In order to solve the technical problems, the invention provides a negative electrode material, and a preparation method and application thereof. The invention provides a preparation method of a negative electrode coating material by optimizing and customizing coating reagents, mainly by optimizing components of a saturated component Sa1, an aromatic component Ar1 and a colloid Re1, so that the prepared negative electrode coating material has good consistency, good charge-discharge multiplying power and cycle life, and relatively low cost. The colloid and the asphaltene have large molecular weight and can be extracted and separated through hexane or butane, so that the tar, asphalt and other coating reagents are optimized and treated in a distillation and extraction mixing mode, the proportion of the saturated component Sa1, the aromatic component Ar1 and the colloid Re1 is regulated and controlled, the purpose of regulating and controlling the components of the coating reagent is further achieved, and the components of the coating reagent are obtained, so that the anode material with excellent performance is obtained.
The first object of the present invention is to provide a negative electrode material, wherein the negative electrode material has a core-shell structure, a negative electrode active material is used as an inner core, and a coating layer coated on the surface of the negative electrode active material is used as a shell layer; the coating agent in the coating layer comprises a saturation fraction Sa1, an aromatic fraction Ar1, colloid Re1 and asphaltene As1;
the mass ratio relationship of the saturation fraction Sa1, the aromatic fraction Ar1, the colloid Re1 and the asphaltene As1 is As follows: w is more than or equal to 0.02 Sa1 ≤0.18，0.05≤W Ar1 ≤0.31，0.32≤W Re1 Less than or equal to 0.62, the balance of W As1 Is contained in the composition; w (W) Sa1 +W Ar1 +W Re1 +W As1 ＝1；
The total molecular weight of each raw material component in the coating agent is 50-10000; the molecular weight of the saturated fraction Sa1 is 150-300, the aromatic fraction Ar1 is 300-500, the colloid Re1 is 500-1500, and the asphaltene As1 is more than 1500.
In one embodiment of the invention, the thickness of the coating layer is 5-2000nm. Further, it is preferably about 60 nm.
In one embodiment of the present invention, the mass ratio relationship of the saturation fraction Sa1, the aromatic fraction Ar1, the colloid Re1, and the asphaltene As1 is: w is more than or equal to 0.04 Sa1 ≤0.14，0.08≤W Ar1 ≤0.27；0.35≤W Re1 Less than or equal to 0.58, the balance of W As1 Is contained in the composition.
In one embodiment of the present invention, the mass ratio relationship of the saturation fraction Sa1, the aromatic fraction Ar1, the colloid Re1, and the asphaltene As1 is: w is more than or equal to 0.05 Sa1 ≤0.12，0.1≤W Ar1 ≤0.25；0.4≤W Re1 Less than or equal to 0.56, the balance of W As1 Is contained in the composition.
The second object of the present invention is to provide a method for preparing the negative electrode material, comprising the steps of: and mixing a carbon precursor containing a saturated component Sa1, an aromatic component Ar1, colloid Re1 and asphaltene As1 with a negative electrode active material, and carbonizing at a high temperature, wherein a coating layer is formed on the surface of the negative electrode active material to obtain the negative electrode material.
In one embodiment of the present invention, the carbon precursor accounts for 1wt% to 10wt% of the total mass of the anode active material and the carbon precursor. Further, it is preferably 5wt%.
In one embodiment of the invention, the carbon precursor is derived from one or more of coal pitch, petroleum pitch, coal tar, petroleum tar, aromatic hydrocarbon, and pitch.
In one embodiment of the invention, high temperature carbonization conditions: the carbonization temperature is 900-1200 ℃, and the reaction time is 1-3h.
A third object of the present invention is to provide a negative electrode sheet comprising the negative electrode material described in the first object, and the negative electrode material obtained by the production method described in the second object.
The fourth object of the invention is to provide an electrochemical device, which comprises a positive plate, a diaphragm, electrolyte and a negative plate, wherein the diaphragm is used for separating the positive plate from the negative plate, and the positive plate is the positive plate.
The invention skillfully utilizes the characteristics of two components of asphalt and tar, and in the coating process, the coating layer has the characteristics of easy uniform coating of small molecular weight components, high carbon content of macromolecules and proper coating thickness, thereby obtaining the uniformly coated quick-filling material. The method specifically comprises the following steps: the saturated component Sa1 and the aromatic component Ar1 have small molecular weight, are favorable for improving the fluidity of a coating reagent and the uniform coating effect, but have low carbonization yield, and the colloid Re1 and asphaltene As1 components have large molecular weight, generally have weaker fluidity, but have high carbonization yield, are main structural components forming a coating layer, and realize good synergistic and complementary effects.
Compared with the prior art, the technical scheme of the invention has the following advantages:
according to the preparation method of the negative electrode material, one, two or more than two different carbonaceous raw materials are matched, coated and carbonized through reasonable optimization of materials, so that the prepared negative electrode material has good charge and discharge first effect, good consistency and relatively low cost.
Drawings
In order that the invention may be more readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings, in which,
fig. 1 is an SEM of the negative electrode material coated with the coating agent obtained in example 1 of the present invention.
Fig. 2 is an SEM of the negative electrode material coated with the coating agent obtained in comparative example 3 of the present invention.
Detailed Description
In order to solve the technical problems in the prior art pointed out in the background art, a negative electrode material and a preparation method thereof are provided.
The first object of the present invention is to provide a negative electrode material, wherein the negative electrode material has a core-shell structure, a negative electrode active material is used as an inner core, and a coating layer coated on the surface of the negative electrode active material is used as a shell layer; the coating agent in the coating layer comprises a saturation fraction Sa1, an aromatic fraction Ar1, colloid Re1 and asphaltene As1;
the mass ratio relationship of the saturation fraction Sa1, the aromatic fraction Ar1, the colloid Re1 and the asphaltene As1 is As follows: w is more than or equal to 0.02 Sa1 ≤0.18，0.05≤W Ar1 ≤0.31，0.32≤W Re1 Less than or equal to 0.62, the balance of W As1 Is contained in the composition; w (W) Sa1 +W Ar1 +W Re1 +W As1 ＝1；
The total molecular weight of each raw material component in the coating agent is 50-10000; the molecular weight of the saturated fraction Sa1 is 150-300, the aromatic fraction Ar1 is 300-500, the colloid Re1 is 500-1500, and the asphaltene As1 is more than 1500.
In a specific embodiment, the thickness of the coating layer is 5-2000nm. Further, it is preferably about 60 nm.
In a specific embodiment, the mass ratio relationship of the saturation fraction Sa1, the aromatic fraction Ar1, the colloid Re1 and the asphaltene As1 is: w is more than or equal to 0.04 Sa1 ≤0.14，0.08≤W Ar1 ≤0.27；0.35≤W Re1 Less than or equal to 0.58, the balance of W As1 Is contained in the composition.
In a specific embodiment, the mass ratio relationship of the saturation fraction Sa1, the aromatic fraction Ar1, the colloid Re1 and the asphaltene As1 is: w is more than or equal to 0.05 Sa1 ≤0.12，0.1≤W Ar1 ≤0.25；0.4≤W Re1 Less than or equal to 0.56, the balance of W As1 Is contained in the composition.
The method for specifically controlling the component content comprises the following steps: selecting coal tar or petroleum tar as a coated carbon source, and detecting by using detection standard NB/SH1T 0509-2010 to obtain saturation fraction Sa1, aromatic fraction Ar1 and colloid Re1; according to the detected detection range of the saturation fraction Sa1, the aromatic fraction Ar1 and the colloid Re1, if the saturation fraction Sa1, the aromatic fraction Ar1 and the colloid Re1 are not in the required range, petroleum tar or coal tar is distilled at a high temperature of about 500 ℃, the volatilization rate of the saturation fraction Sa1 and the aromatic fraction Ar1 is controlled by controlling the distillation time, and the proportion of the saturation fraction Sa1, the aromatic fraction Ar1 and the colloid Re1 is controlled within the control range.
The second object of the present invention is to provide a method for preparing the negative electrode material, comprising the steps of: and mixing a carbon precursor containing a saturated component Sa1, an aromatic component Ar1, colloid Re1 and asphaltene As1 with a negative electrode active material, and carbonizing at a high temperature, wherein a coating layer is formed on the surface of the negative electrode active material to obtain the negative electrode material.
In a specific embodiment, the carbon precursor accounts for 1wt% to 10wt% of the total mass of the anode active material and the carbon precursor. Further, it is preferably 5wt%.
In particular embodiments, the carbon precursor is derived from at least one or more of coal pitch, petroleum pitch, coal tar, petroleum tar, aromatic hydrocarbon, and pitch.
In specific examples, high temperature carbonization conditions: the carbonization temperature is 900-1200 ℃, and the reaction time is 1-3h. Preferably, the carbonization temperature is 900 ℃, 950 ℃, 1000 ℃, 1050 ℃, 1100 ℃, 1150 ℃, 1200 ℃ and the like, and the reaction time is 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours. Or any value between any two values.
In a specific example, the overall yield of the carbonized carbon precursor is greater than or equal to 30wt% (the residual yield after carbonization of the coating reagent, i.e., the mass ratio of carbon formed after carbonization).
In specific embodiments, the negative electrode active material is a graphite material including, but not limited to, one or a combination of artificial graphite, natural graphite, mesophase carbon microbeads, composite graphite.
A third object of the present invention is to provide a negative electrode sheet comprising the negative electrode material described in the first object, and the negative electrode material obtained by the production method described in the second object.
The fourth object of the invention is to provide an electrochemical device, which comprises a positive plate, a diaphragm, electrolyte and a negative plate, wherein the diaphragm is used for separating the positive plate from the negative plate, and the positive plate is the positive plate.
In particular embodiments, the separator may be a variety of materials suitable for use in electrochemical device separators in the art, and may be, for example, a combination of one or more of polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester, natural fibers, and the like.
In a specific embodiment, the electrolyte includes an organic solvent, an electrolyte lithium salt, and an additive. Wherein the electrolyte lithium salt is selected from LiPF used in high-temperature electrolyte 6 And/or LiBOB, and can also be LiBF used in low-temperature electrolyte 4 、LiBOB、LiPF 6 At least one of (a) and (b); liBF used in the overcharge-preventing electrolyte may also be used 4 、LiBOB、LiPF 6 At least one of LiTFSI; liClO may also be 4 、LiAsF 6 、LiCF 3 SO 3 、LiN(CF 3 SO 2 ) 2 At least one of them. The organic solvent may be a cyclic carbonate, including PC, EC; chain carbonates, including DFC, DMC, or EMC; carboxylic esters, including MF, MA, EA, MP, and the like, are also contemplated. The additives include, but are not limited to, film forming additives, conductive additives, flame retardant additives, overcharge prevention additives, and control of H in the electrolyte 2 Additives for O and HF content,At least one of an additive for improving low temperature performance and a multifunctional additive.
In a specific embodiment, the positive electrode sheet includes a positive electrode current collector and an active material layer coated on the current collector, the active material layer may be of a chemical formula such as Li a Ni x Co y M z O 2-b N b (wherein 0.95.ltoreq.a.ltoreq.1.2, x)>0, y.gtoreq.0, z.gtoreq.0, and x+y+z.ltoreq.1, 0.ltoreq.b.ltoreq.1, M is selected from combinations of one or more of Mn, al, N is selected from combinations of one or more of F, P, S), the positive electrode active material may also be a combination of one or more of compounds including but not limited to LiCoO 2 、LiNiO 2 、LiVO 2 、LiCrO 2 、LiMn 2 O 4 、LiCoMnO 4 、Li 2 NiMn 3 O 8 、LiNi 0.5 Mn 1.5 O 4 、LiCoPO 4 、LiMnPO 4 、LiFePO 4 、LiNiPO 4 、LiCoFSO 4 、CuS 2 、FeS 2 、MoS 2 、NiS、TiS 2 And the like. The positive electrode active material may be further subjected to a modification treatment, and a method of modifying the positive electrode active material should be known to those skilled in the art, for example, the positive electrode active material may be modified by coating, doping, etc., and the material used for the modification treatment may be one or more combinations including but not limited to Al, B, P, zr, si, ti, ge, sn, mg, ce, W, etc. The positive current collector is typically a structure or part that collects current, and the positive current collector may be any of a variety of materials suitable in the art for use as a positive current collector for an electrochemical device, for example, the positive current collector may be a material including, but not limited to, a metal foil, etc., and more particularly may be a material including, but not limited to, aluminum foil, etc.
The present invention will be further described with reference to the accompanying drawings and specific examples, which are not intended to be limiting, so that those skilled in the art will better understand the invention and practice it.
Example 1
The embodiment provides an electrochemical device, which comprises a positive plate, a diaphragm, electrolyte and a negative plate, wherein the negative electrode comprises a negative current collector and a negative electrode material layer, and the negative electrode material layer is arranged on the surface of the negative current collector. The electrochemical device may be a lithium ion battery, a button cell battery, or the like. This embodiment is illustrated by a button cell.
(1) And (3) a positive electrode: a metallic lithium sheet was used as the positive electrode sheet.
(2) Preparation of negative electrode
2.1, a preparation method of a negative electrode material, comprising the following steps:
the low-temperature petroleum tar is selected as a coated carbon source, and the contents of the saturation fraction Sa1, the aromatic fraction Ar1 and the colloid Re1 are controlled by a high-temperature distillation mode and detection standards of NB/SH/T0509-2010: meets Sa1 = 0.11, ar1 = 0.19, re1 = 0.55, as1 = 0.15. Mixing the coated carbon source with graphite and adding N 2 Under the condition of high temperature of 900 ℃ for 8 hours, the anode material with the surface coated with the coating agent is obtained, the characterization result is shown in figure 1, and the obtained anode material is uniformly coated.
2.2, grinding the prepared cathode material into powder, controlling granularity by using a 400-mesh screen, taking N-methyl pyrrolidone as a solvent, mixing the cathode material, carbon black and PVDF according to a mass ratio of 85:5:10, preparing uniformly mixed slurry (with a viscosity of 3000 pcs), coating on a copper foil with a diameter of 8 mu m, and vacuum drying at 60 ℃ for 12 hours. After drying, rolling by a roller press, compacting to a density of 1.50g/cc, punching the pole piece to 12mm 2 The wafer of the negative electrode plate is obtained.
(3) A diaphragm: a porous polyethylene film having a thickness of 7 μm was selected as a separator.
(4) Preparation of electrolyte:
lithium hexafluorophosphate (LiPF) 6 ) Dissolved in a mixed solvent of dimethyl carbonate (DEC), ethylene Carbonate (EC) and methyl ethyl carbonate (EMC) (mass ratio of the three is 3:5: 2) And obtaining electrolyte.
(5) Preparation of the battery:
and winding the positive electrode plate, the diaphragm and the negative electrode plate into an electric core in a glove box, wherein the capacity of the electric core is about 5Ah. The diaphragm is positioned between the adjacent positive plate and the negative plate, the positive electrode is led out by spot welding of an aluminum tab, and the negative electrode is led out by spot welding of a nickel tab; then placing the battery core in an aluminum plastic packaging bag, baking, injecting the electrolyte, and finally manufacturing the button cell through the procedures of packaging, formation, capacity division and the like.
Example 2
This embodiment differs from embodiment 1 in that: medium-low temperature petroleum tar is selected as a coated carbon source, and the saturation fraction Sa1, the aromatic fraction Ar1 and the colloid Re1 are controlled;
the conditions of Sa1 = 0.07, ar1 = 0.18, re1 = 0.52 are satisfied.
Example 3
This embodiment differs from embodiment 1 in that: medium and high temperature petroleum tar is selected as a coated carbon source, and the saturation fraction Sa1, the aromatic fraction Ar1 and the colloid Re1 are controlled;
the conditions of Sa1 = 0.08, ar1 = 0.22, re1 = 0.49 are satisfied.
Example 4
This embodiment differs from embodiment 1 in that: selecting medium-high temperature coal tar as a coated carbon source, and controlling saturation fraction Sa1, aromatic fraction Ar1 and colloid Re1;
meets Sa1 = 0.10, ar1 = 0.21; re1 = 0.53.
Comparative example 1:
the present comparative example differs from example 1 in that: selecting low-viscosity petroleum residuum as a coated carbon source, and controlling saturation fraction Sa1, aromatic fraction Ar1 and colloid Re1;
meets Sa1 = 0.01, ar1 = 0.24; re1 = 0.55.
Comparative example 2:
the present comparative example differs from example 1 in that: selecting high-temperature coal pitch as a coated carbon source, and controlling saturation fraction Sa1, aromatic fraction Ar1 and colloid Re1;
meets Sa1 = 0.08, ar1 = 0.39; re1 = 0.53.
Comparative example 3:
the present comparative example differs from example 1 in that: selecting petroleum asphalt to coat a carbon source, and controlling the saturation fraction Sa1, the aromatic fraction Ar1 and the colloid Re1; the structural characterization of the obtained wrapped-type anode material is shown in fig. 2, and the wrapping of the obtained anode material is uneven.
Meets Sa1 = 0.07, ar1 = 0.22; re1 = 0.67.
Comparative example 4:
the present comparative example differs from example 1 in that: selecting distilled wash oil as a coated carbon source, and controlling saturation fraction Sa1, aromatic fraction Ar1 and colloid Re1;
meets Sa1 = 0.01, ar1 = 0.04; re1 = 0.31.
Comparative example 5
This embodiment differs from embodiment 1 in that: selecting high Wen Danyou pitch to coat a carbon source, and controlling saturation fraction Sa1, aromatic fraction Ar1 and colloid Re1;
the conditions of Sa1 = 0.10, ar1 = 0.18, re1 = 0.52 are satisfied.
Comparative example 6
This embodiment differs from embodiment 1 in that: selecting medium-low temperature coal tar as a coated carbon source, and controlling saturation fraction Sa1, aromatic fraction Ar1 and colloid Re1;
the conditions of Sa1 = 0.06, ar1 = 0.22, re1 = 0.63 are satisfied.
Comparative example 7
This embodiment differs from embodiment 1 in that: medium-low temperature petroleum tar is selected as a coated carbon source, and the saturation fraction Sa1, the aromatic fraction Ar1 and the colloid Re1 are controlled;
the conditions of Sa1 = 0.05, ar1 = 0.33, re1 = 0.52 are satisfied.
Comparative example 8
This embodiment differs from embodiment 1 in that: selecting medium-low temperature coal tar as a coated carbon source, and controlling saturation fraction Sa1, aromatic fraction Ar1 and colloid Re1;
it satisfies Sa 1=0.01, ar1=0.43, re1=0.30.
Performance testing
The above examples and comparative examples were subjected to capacity retention and cycle life testing. Each set took 5EA cells to charge and discharge 0.05c 5 times, activating the material. Then 10 charge-discharge cycles are carried out at 1C to fix the volume. And (3) according to the constant volume capacity, three multiplying powers of 3C and 5C are designed for charge and discharge, each multiplying power circulates for 10 times, and the discharge capacity retention rate is calculated according to the average value of 10 times of circulation. And (3) carrying out cycle test, namely carrying out 3C full charge and 3C full discharge on the prepared lithium ion battery in a voltage interval of 2.8V-4.3V at 25 ℃, and recording the cycle number when the capacity is attenuated to 80% of the rated capacity, wherein the cycle number is recorded in the following table 1.
TABLE 1
As can be seen from table 1, when coal tar a or petroleum tar a is selected as a coated carbon source, the content of the saturated component Sa1, the aromatic component Ar1 and the content of the colloid Re1 are reasonably controlled, so that the coating has the characteristics of easy uniform coating of small molecular weight components, high carbon content of macromolecules and proper coating thickness, and further a uniformly coated quick charge material is obtained.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations and modifications of the present invention will be apparent to those of ordinary skill in the art in light of the foregoing description. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.

Claims (10)

1. The negative electrode material is characterized by being of a core-shell structure, taking a negative electrode active material as an inner core and taking a coating layer coated on the surface of the negative electrode active material as a shell layer; the coating agent in the coating layer comprises a saturation fraction Sa1, an aromatic fraction Ar1, colloid Re1 and asphaltene As1;
the contents of the saturation fraction Sa1, the aromatic fraction Ar1, the colloid Re1 and the asphaltene As1 are As follows, and the contents are counted in percentage by mass: w is more than or equal to 0.02 Sa1 ≤0.18，0.05≤W Ar1 ≤0.31，0.32≤W Re1 Less than or equal to 0.62, the balance of W As1 Is contained in the composition; w (W) Sa1 +W Ar1 +W Re1 +W As1 ＝1；
The total molecular weight of each component in the coating agent is 50-10000.
2. The anode material according to claim 1, wherein the thickness of the coating layer is 5 to 2000nm.
3. The negative electrode material according to claim 1, wherein the contents of the saturation fraction Sa1, the aromatic fraction Ar1, the colloid Re1, and the asphaltene As1 are: w is more than or equal to 0.04 Sa1 ≤0.14，0.08≤W Ar1 ≤0.27；0.35≤W Re1 Less than or equal to 0.58, the balance of W As1 Is contained in the composition.
4. The negative electrode material according to claim 1, wherein the contents of the saturation fraction Sa1, the aromatic fraction Ar1, the colloid Re1, and the asphaltene As1 are: w is more than or equal to 0.05 Sa1 ≤0.12，0.1≤W Ar1 ≤0.25；0.4≤W Re1 Less than or equal to 0.56, the balance of W As1 Is contained in the composition.
5. A method for producing the anode material according to any one of claims 1 to 4, comprising the steps of: and mixing a carbon precursor containing a saturated component Sa1, an aromatic component Ar1, colloid Re1 and asphaltene As1 with a negative electrode active material, and carbonizing at a high temperature, wherein a coating layer is formed on the surface of the negative electrode active material to obtain the negative electrode material.
6. The method according to claim 5, wherein the carbon precursor accounts for 1wt% to 10wt% of the total mass of the anode active material and the carbon precursor.
7. The method of claim 5, wherein the carbon precursor is derived from one or more of coal pitch, petroleum pitch, coal tar, petroleum tar, aromatic hydrocarbon, and pitch.
8. The method according to claim 5, wherein the high-temperature carbonization conditions: the carbonization temperature is 900-1200 ℃, and the reaction time is 1-3h.
9. A negative electrode sheet comprising the negative electrode material according to any one of claims 1 to 4, and the negative electrode material obtained by the production method according to any one of claims 5 to 8.
10. An electrochemical device comprising a positive electrode sheet, a separator, an electrolyte, and a negative electrode sheet, wherein the separator is used for separating the positive electrode sheet and the negative electrode sheet, and the negative electrode sheet is the negative electrode sheet according to claim 9.
CN202311123964.0A 2023-09-01 2023-09-01 Negative electrode material and preparation method and application thereof Pending CN117154043A (en)

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