CN113809328A - Negative electrode material composition, slurry, lithium-carbon material negative electrode and lithium ion battery - Google Patents
Negative electrode material composition, slurry, lithium-carbon material negative electrode and lithium ion battery Download PDFInfo
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Abstract
The invention relates to a negative electrode material composition, slurry, a lithium-carbon material negative electrode and a lithium ion battery. The composition comprises the lithium-carbon material, the conductive agent and the binder, wherein a side chain polar group is introduced into the binder, so that the binder can form a hydrogen bond with hydrogen on an active material and/or a current collector, the binding property is enhanced, and the contact between a coating and the current collector is tighter, so that the battery capacity is slowly attenuated, and the cycle life of the battery is prolonged.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a material for a lithium ion battery, and a preparation method and application thereof.
Background
As petroleum resources are gradually depleted, fuel vehicles, which are large consumers of fuel, are gradually being replaced by electric vehicles. Along with the rapid rise of electric vehicles, batteries, which are important components of electric vehicles, have also been rapidly developed. The lithium ion battery is widely used for electric vehicles due to high energy density, large volume energy density and wide application temperature range. However, as the preparation process of the lithium ion battery is mature, the energy density of the lithium ion battery using the graphite material as the negative electrode is close to the limit. However, the rapid development of electric vehicles has increasingly raised the energy density requirement of batteries, and the existing lithium ion batteries cannot meet the development requirement of electric vehicles. The adoption of new cathode materials is one of the important methods for improving the energy density of the battery. The lithium metal cathode has high gram capacity (3860mAh/g, ten times of that of a graphite cathode) and the lowest electrode potential (-3.04V vs standard hydrogen potential), and is an ideal material for improving the energy density of the lithium ion battery.
However, the metallic lithium is active and can react with water and most organic solvents, and particularly, the granular metallic lithium material has a large specific surface and reacts more violently. Therefore, only nonpolar or less polar organic solvents can be used for slurry coating in the preparation process of the granular lithium metal negative electrode, and only nonpolar or less polar binders can be used for the slurry coating. For example, Chinese patent application (application No.: CN201380073237.6) relating to lithium powder anodes uses saturated polyolefins (e.g., polyethylene), polyolefin-copolymers (e.g., ethylene-propylene-copolymer), unsaturated diene polymers (e.g., butadiene rubber), or diene copolymers (e.g., styrene-butadiene rubber) as binders for lithium metal powder slurry coating. Chinese patent application (application No. CN 201710618561.1) relating to a lithium-containing electrode, a preparation method thereof and a lithium ion battery containing the electrode adopts styrene-butadiene rubber and polystyrene as a binder for the slurry coating of lithium-carbon composite particles.
Although the binder used by the metal lithium particle negative electrode material solves the problem of matching with a nonpolar or less polar organic solvent, the binding force between the binder and the metal lithium particle negative electrode material and a current collector is small, and a coating is easy to separate from the surface of the current collector, so that the electron transfer impedance is increased, even the electrochemical activity is lost, the battery capacity attenuation is accelerated, and the battery cycle life is shortened.
Disclosure of Invention
In order to solve the above problems, the present invention employs a novel binder obtained by subjecting an unsaturated diene polymer or an unsaturated diene copolymer to thermal oxidation treatment. Under the action of thermal oxygen, alpha-H of carbon-carbon double bonds is oxidized into hydroxyl and/or aldehyde groups, and polar groups such as side chain hydroxyl and/or aldehyde groups are introduced, so that hydrogen bonds can be formed between the binder and the active material and/or the current collector, the binding property is enhanced, the contact between the coating and the current collector is tighter, the capacity attenuation of the battery is slow, and the cycle life of the battery is prolonged.
The invention can be realized by the following technical scheme:
1. a negative electrode material composition, the composition comprising: a lithium-carbon material, a conductive agent and a binder,
wherein the binder is a polymer having a molecular weight in the range of 104-106Has at least one of the following structures:
wherein X% represents the mass fraction of X structural units in the binder, Y% represents the mass fraction of Y structural units,
z% represents the mass fraction of Z structural units, and satisfies the following condition:
X％+Y％+Z％＝100％
0≤Z％≤33％
0≤X％≤35％
0≤Y％≤35％
X％+Y％≥Z％，
or
Wherein X '% represents the mass fraction of X' structural units in the binder, Y '% represents the mass fraction of Y' structural units,
z '% represents the mass fraction of the Z' structural unit, L '% represents the mass fraction of the L' structural unit in the binder, and the mass fractions satisfy:
X’％+Y’％+Z’％+L’％＝100％
0≤Z’％≤30％
0≤X’％≤40％
0≤Y’％≤40％
0≤L’％≤5％
X’％+Y’％≥Z’％
wherein: r0Is hydrogen or a hydrocarbyl or hydroxy group;
R1、R2、R3、R4、R5、R6、R7、R8、R9、R10is hydrogen or a hydrocarbyl group;
the constitutional units shown in parentheses may be arranged arbitrarily or in an ordered manner.
2. The negative electrode material composition as described above, wherein the binder has a viscosity of 500-5000 mPa.s in a 25% (mass fraction) toluene solution at 25 ℃.
3. The negative electrode material composition as described above, wherein the binder is contained in the negative electrode material composition in a mass percentage of 0.1 to 10%.
4. The negative electrode material composition as described above, wherein the lithium-carbon material is a composite material of carbon material microspheres and metallic lithium, wherein the carbon material microspheres are microspherical porous carbon skeletons formed by interlacing and agglomerating fibrous carbon nanomaterials, have D50 of 5-30 micrometers and pores of 5-50 nanometers, and the metallic lithium is filled in the pores and/or surfaces of the carbon material microspheres.
5. The negative electrode material composition as described above, wherein the carbon material microspheres further comprise amide organic additives modified on the surface of the fibrous carbon nanomaterial and uniformly distributed inside and on the surface of the microspherical porous carbon skeleton.
6. The negative electrode material composition as described above, wherein the fibrous carbon nanomaterial is selected from one or more of single-walled carbon nanotubes, multi-walled carbon nanotubes, aminated carbon nanotubes, carboxylated carbon nanotubes, hydroxylated carbon nanotubes, nitrogen-doped carbon nanotubes, phosphorus-doped carbon nanotubes, carbon nanofibers, and graphitized carbon nanofibers.
7. The anode material composition as described above, wherein the amide organic additive is one or more organic polymers selected from polyacrylamide, polyvinylpyrrolidone, water-soluble polyamide resin, urea resin, and water-soluble polyurethane, or one or more small molecule organic compounds selected from N-methylformamide, N-diethylformamide, N-methylacetamide, N' -tetramethylurea, and N-methylpyrrolidone.
8. The negative electrode material composition as described above, wherein the weight ratio of the carbon material microspheres and the metallic lithium in the lithium carbon material is 1:0.1 to 1: 4.
9. The negative electrode material composition as described above, wherein the lithium carbon material is contained in an amount of 80% to 95% by mass in the negative electrode material composition.
10. The negative electrode material composition as described above, wherein the conductive agent includes acetylene black, Ketjen Black (KB), conductive graphite, graphene, carbon nanotubes.
11. The negative electrode material composition as described above, wherein the conductive agent is contained in the negative electrode material composition in an amount of 0.1% to 10% by mass.
12. A slurry comprising the anode material composition as described above and a solvent, wherein the solid content of the slurry is 10 to 40 mass%.
13. The slurry as described above, wherein the solvent is a non-polar or weakly polar solvent comprising at least one of xylene, p-xylene, m-xylene, o-xylene, benzene, pentane, isopentane, n-hexane, cyclohexane, petroleum ether, n-heptane, octane, nonane, decane, tetrahydrofuran.
14. A lithium carbon material negative electrode comprising a current collector and a coating layer on a surface of the current collector, the coating layer being formed by coating and drying the slurry as above.
15. The lithium carbon material negative electrode as described above, wherein the current collector includes: copper foil, carbon-coated copper foil, punched copper foil and copper mesh.
16. A lithium ion battery comprises the lithium-carbon material negative electrode.
The invention has at least one of the following advantages:
(1) the binder introduces polar groups (hydroxyl and/or aldehyde groups) so that hydrogen bonds can be formed between the binder and the active material and/or the current collector, and the binding property is enhanced.
(2) The battery capacity decays slowly and the battery cycle life increases.
(3) The improved process of the binder is simple and easy to amplify.
Drawings
FIG. 1 is a discharge capacity cycling chart of the cells of the test group and the control group in the example of the present invention.
Detailed Description
The negative electrode material composition, slurry, lithium carbon material negative electrode, and lithium ion battery of the present invention are described in detail below.
1 negative electrode material composition
1.1 the anode material composition of the present invention comprises: a lithium carbon material, a conductive agent and a binder, these components being in solid form.
1.2 Binders
1.2.1 Binder structures
1.2.1.1 the binder is a polymeric material having at least one of the following structures:
wherein X% represents the mass fraction of the X structural units in the binder, Y% represents the mass fraction of the Y structural units, and Z% represents the mass fraction of the Z structural units, satisfying:
X％+Y％+Z％＝100％
0≤Z％≤33％
0≤X％≤35％
0≤Y％≤35％
X％+Y％≥Z％，
or
Wherein X '% represents the mass fraction of X' structural units in the binder, Y '% represents the mass fraction of Y' structural units, Z '% represents the mass fraction of Z' structural units, and L '% represents the mass fraction of L' structural units in the binder, satisfying:
X’％+Y’％+Z’％+L’％＝100％
0≤Z’％≤30％
0≤X’％≤40％
0≤Y’％≤40％
0≤L’％≤5％
X’％+Y’％≥Z’％
wherein: r0Is hydrogen or a hydrocarbyl or hydroxy group;
R1、R2、R3、R4、R5、R6、R7、R8、R9、R10is hydrogen or a hydrocarbon radical, e.g.
C1-C10 aliphatic hydrocarbon groups or C6-C20 aromatic hydrocarbon groups;
the constitutional units shown in parentheses may be arranged arbitrarily or in an ordered manner. .
1.2.2 the molecular weight range of the binder is 104-106。
1.2.3 viscosity of the binder at 25% by mass in a toluene solution at 25 ℃ of 500-5000 mPa.s
1.2.4 the binder can be obtained by:
1.2.4.1 heating the binder material in air at a certain temperature for a certain time.
1.2.4.2 the binder material is a polymer having the following structure:
wherein: r1、R2、R3、R4、R5、R6Is hydrogen or a hydrocarbon group.
Wherein: a is more than 0 and b is more than or equal to 0.
Wherein: the structural units can be arranged randomly or orderly.
1.2.4.3 the binder material may be at least one of diene polymers and copolymers thereof including natural rubber, butadiene rubber, polyisoprene rubber, butyl rubber, polyisobutylene isoprene rubber, SBR (butadiene-styrene random copolymer), SBS (styrene-butadiene-styrene block copolymer), SIS (styrene-isoprene-styrene block copolymer).
1.2.4.4 the temperature range for heating the feedstock is 60-200 deg.C, preferably 140-180 deg.C.
The heating time is in the range of 6 hours to 24 hours, preferably in the range of 8 to 12 hours, 1.2.4.5.
1.2.4.6 under the action of heat and oxygen, the double bonds α -H of the binder raw material are oxidized to hydroxyl groups, some of which are further dehydrated to form aldehydes. These polar side chain groups can form hydrogen bonds with the hydrogen on the lithium carbon material or the current collector, thereby providing stronger binding power.
1.2.5 Binder content
1.2.5.1 in the negative electrode material composition, the binder content is 0.1 to 10% (mass fraction), and preferably in the range of 1 to 5% (mass fraction).
1.3 lithium carbon Material
1.3.1 the lithium carbon powder of the present invention is a composite material of carbon material microspheres and metallic lithium, wherein the metallic lithium is filled in the pores and/or the surface of the carbon material microspheres.
1.3.2 lithium carbon material has a D50 of between 5-30 microns, preferably has a D90 of between 15-35 microns; and/or the weight ratio of the carbon material microspheres to the metal lithium is 1: 0.1-1: 4, preferably 1: 2-1: 3.
1.3.3 carbon material microspheres have a D50 of between 5 and 15 microns, preferably have a D90 of between 15 and 20 microns.
1.3.4 carbon material microspheres have a total pore volume of 0.1 to 5.0ml/g, preferably 0.5 to 2.5 ml/g: and/or the pores in the carbon material microspheres have an average pore diameter of 10 to 50 nm, preferably 15 to 30 nm.
1.3.5 the carbon material microsphere is a microspherical porous carbon skeleton formed by mutually intertwining and agglomerating fibrous carbon nano materials.
1.3.6 the carbon material microsphere can also be a carbon material microsphere modified by an amide organic additive,
which comprises a microspherical porous carbon skeleton composed of fibrous carbon nanomaterials which are staggered with each other, and an amide organic additive which is modified on the surface of the fibrous carbon nanomaterials and is uniformly distributed in and on the microspherical porous carbon skeleton, wherein,
the fibrous carbon nano material is selected from one or more of single-walled carbon nano tube, multi-walled carbon nano tube, aminated carbon nano tube, carboxylated carbon nano tube, hydroxylated carbon nano tube, nitrogen-doped carbon nano tube, phosphorus-doped carbon nano tube, carbon nano fiber and graphitized carbon nano fiber;
the amide organic additive is one or more organic polymers selected from polyacrylamide, polyvinylpyrrolidone, water-soluble polyamide resin, urea-formaldehyde resin and water-soluble polyurethane, or one or more small-molecule organic compounds selected from N-methylformamide, N, N-diethylformamide, N-methylacetamide, N, N, N ', N' -tetramethylurea and N-methylpyrrolidone.
The mass ratio of the fibrous carbon nano material to the amide organic additive in the carbon material microsphere is 2:1 to 20:1, preferably 5:1 to 15: 1.
1.3.7 in the negative electrode material composition, the content of the lithium carbon material is 80% to 95%, and preferably in the range of 80% to 85% (mass fraction).
1.4 conductive Agents
1.4.1 the negative electrode material composition further comprises a conductive agent, including acetylene black, Ketjen Black (KB), conductive graphite, graphene, carbon nanotubes, and the like.
1.4.2 the content of the conductive agent in the negative electrode material composition is 0.1-10%, and the preferable range is 1-5% (mass fraction).
2 slurry containing negative electrode material composition
2.1 the negative electrode material composition of the present invention can be applied to a current collector as a slurry to form a negative electrode. The slurry may include a negative electrode material composition and a solvent.
2.2 the solids content of the slurry is in the range of 10 to 40%, preferably in the range of 20 to 30%. Wherein the solid content is (binder mass + conductive agent mass + active substance mass)/(solvent mass + binder mass + conductive agent mass + active substance mass) × 100%.
2.3 the solvent in the slurry is a non-polar or weakly polar solvent, including at least one of xylene, m-xylene, o-xylene, p-xylene, benzene, pentane, isopentane, n-hexane, cyclohexane, petroleum ether, n-heptane, octane, nonane, decane, tetrahydrofuran.
3 lithium carbon material negative electrode
3.1 the lithium carbon material negative electrode of the present invention comprises a current collector and a coating layer on the surface of the current collector, the coating layer being formed by coating or drying the above slurry.
3.2 the current collector here can be a copper foil, a carbon-coated copper foil or a punched copper foil.
3.3 in the dried coating, the content of the binder is 0.1-10%, preferably 1-5% (mass fraction); the content of the lithium-carbon material is 80-95%, preferably 80-85% (mass fraction); the content of the conductive agent is 0.1-10%, preferably 1-5% (mass fraction).
Preparation method of 4 lithium carbon material negative electrode
4.1 method for preparing negative electrode
4.1.1 preparing glue, adding the thermally treated binder into a nonpolar or weakly polar solvent in an argon glove box, and stirring to completely dissolve the binder;
4.1.2 adding a conductive agent and a lithium-carbon material into the glue, and continuously stirring;
4.1.3 coating the slurry after mixing the slurry on a copper foil;
4.1.4 drying and evaporating the solvent after coating to obtain the lithium-carbon material negative electrode.
4.1.5 the solids content of the slurry is in the range of 10 to 40%, preferably in the range of 20 to 30%.
5 lithium ion battery using lithium carbon material negative electrode.
5.1 the active material adopted by the anode of the lithium ion battery is lithium cobaltate, lithium manganate, lithium iron phosphate, lithium iron manganese phosphate, lithium nickel manganese oxide, lithium manganese rich base, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminate, elemental sulfur and sulfur carbon composite material.
5.2 the electrolyte of the lithium ion battery consists of lithium salt and solvent, wherein the concentration of the lithium salt is 0.1-10 mol/L, and the preferable concentration is 0.8-1.5 mol/L; wherein the lithium salt comprises lithium hexafluorophosphate (LiPF)6) Lithium perchlorate (LiClO)4) Lithium bis (oxalato) borate (LiBOB), lithium difluoro (oxalato) borate (lidob), lithium trifluoro (CF3 CO)3Li), lithium bistrifluoromethylsulfonyl imide (LiTFSI), lithium bistrifluorosulfonimide (LiFSI); wherein the solvent comprises: at least one of ethylene carbonate, propylene carbonate, fluoroethylene carbonate, vinylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, 1, 3-dioxolane, 4-methyl-1, 3-dioxolane, 2-methyl-1, 3-dioxolane and ethylene glycol dimethyl ether.
5.3 the diaphragm of the lithium ion battery can be a single-layer diaphragm, including a polyethylene diaphragm, a polypropylene diaphragm, a polyvinylidene fluoride diaphragm, a polytetrafluoroethylene diaphragm, a polyimide diaphragm, a polyethylene terephthalate diaphragm, a polyester diaphragm, a polyamide diaphragm and cellulose; or a composite diaphragm, which is formed by compounding at least two single-layer diaphragms; the surface of the diaphragm can be coated with a coating, and the coating can be an aluminum oxide coating, a silicon dioxide coating, a titanium dioxide coating, a barium titanate coating, a boehmite coating, a poly-melamine coating, a polyacrylonitrile coating and a polyaniline coating.
6 examples
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Further, the following examples are exemplary in terms of various product structure parameters, various reaction participants and process conditions, but through a lot of experiments, the inventors of the present invention have verified that other different structure parameters, other types of reaction participants and other process conditions listed above are applicable and can achieve the claimed technical effects.
The test materials and equipment used in the examples were as follows:
6.1 preparation of carbon Material microspheres
Weighing 50g of carbon nano tube, adding 5L of deionized water, adding 4.5g of polyvinylpyrrolidone, and continuously stirring for 3 hours at the stirring speed of 1500 r/min. Then, adding the stirred carbon nano tube slurry into spray drying equipment for spray drying, wherein the parameters of the spray drying equipment are as follows: the air inlet temperature is 200 ℃, the spraying pressure is 40MPa, and the sample injection amount is 250 ml/h. The above process was repeated to obtain carbon powder meeting the experimental requirements.
6.2 preparation of lithium carbon powder
And transferring the carbon nanotube balls obtained by spray drying into an argon glove box (the water content is less than or equal to 1ppm, and the oxygen content is less than or equal to 1 ppm). Weighing 100g of carbon nanotube microspheres and 250g of metal lithium, sequentially adding the carbon nanotube microspheres and the metal lithium into a reaction kettle, setting the temperature at 210 ℃, stirring for 60min at the stirring speed of 2500r/min, and then cooling to room temperature to obtain the lithium carbon powder.
6.3 treatment of styrene butadiene rubber
6.3.1 test group treatment of styrene butadiene rubber
2 g of styrene-butadiene rubber is weighed and placed in a constant temperature box, and thermal oxidation is carried out for 12 hours under the condition of keeping the temperature at 140 ℃.
6.3.2 treatment of styrene butadiene rubber as control
The styrene-butadiene rubber of the control group is not treated.
6.4 characterization of the infrared spectrum of the styrene butadiene rubber of the test group and the control group.
As can be seen from the infrared spectrum, the SBR of the experimental group and the control group has the same peak comprising 3024cm-1Peak is carbon-carbon double bond (-CH ═ CH)2) Stretching and contracting vibration of the upper C-H bond; 2915cm-1And 2843cm-1The peak is methylene-CH2-a stretching vibration peak of the C-H bond on; 1449cm-1The peak is methylene-CH2-C-H bond scissor vibration peak on; 963cm-1And 910cm-1Peak is carbon-carbon double bond (-CH ═ CH)2) An out-of-plane bending vibration peak of the upper C-H bond; 758cm-1And 698cm-1The peak is the characteristic peak of the single benzene.
The difference between the two is also seen in the infrared spectrum, and the SBR of the experimental group has a new spectral peak, wherein 1710cm-1The peak is the stretching vibration peak of carbonyl group, 3418cm-1The peak is the stretching vibration peak of hydroxyl, 1200cm-1The peak is the deformation vibration peak of the C-O bond. This suggests that polar hydroxyl and aldehyde groups can be introduced into the SBR chain by the action of thermal oxygen.
6.5 lithium carbon powder coating test
In an argon atmosphere, 0.5g of experimental group SBR0 and 20g of p-xylene are mixed and stirred for 1 hour, then 4g of lithium carbon material and 1g of acetylene black are added, and stirring is continued for 3 hours after mixing. And (3) coating the stirred slurry on the surface of copper foil, wherein the thickness of a coating scraper is 200 microns, and drying the slurry for 12 hours at the temperature of 60 ℃ to obtain the experimental group negative pole piece.
The control SBR adopts the same proportion and preparation flow as the test SBR to prepare the negative pole piece.
6.6 test of 180-degree peel strength of pole pieces of experimental group and control group
The 3M adhesive tape was adhered to a test group of pole pieces with an adhesion length of 30mm and an adhesion width of 25mm, the coating of the pole pieces was peeled off from the pole pieces with a peeling speed of 10mm/s, the change in the peeling tension was recorded using a universal tester, and then the magnitude of the tension at 20mm peeling was compared as shown in Table 1.
And testing the peel strength of the pole piece of the control group by adopting the same testing method as the testing group.
As can be seen from the table, the peel strength of the pole piece of the test group is 2.4 times that of the pole piece of the control group, which indicates that the polar hydroxyl group and aldehyde group introduced into the SBR chain by the action of thermal oxygen play a role in enhancing the adhesion between the pole piece and the negative electrode.
| Group of | 180 DEG peel strength gf/mm |
| Test group pole piece | 0.24 |
| Control group pole piece | 0.58 |
Table 1: comparison of the peel force of the test and control electrode
6.7 Experimental and control Battery Assembly test
And punching the dried test group pole piece and the dried control group pole piece into a wafer with the diameter of 15mm, and taking the wafer as a button cell pole piece for later use. And similarly, the lithium iron phosphate positive plate is also punched into a round plate with the same size.
And (3) sequentially placing the negative plate, the diaphragm, the positive plate, the gasket and the elastic sheet of the test group into a CR2025 type button battery shell in an argon glove box (the water content is less than or equal to 1ppm and the oxygen content is less than or equal to 1ppm), adding electrolyte, and packaging to form the button battery.
The button cell charging and discharging test is completed on a cell tester, the charging and discharging current is 0.1C (1C is 170mAh/g), and the charging and discharging test voltage range is 4.1V-2.5V.
Fig. 1 is a discharge capacity cycling chart of the cells of the test group and the control group. As can be seen from the figure, the capacity of the cells in the experimental group decayed more slowly because the experimental group used the SBR treated with thermal oxidation and contained polar groups (hydroxyl and aldehyde groups) so that the adhesion of the negative electrode coating to the current collector was better, and the negative electrode did not detach during the cycling, and thus the capacity decreased more slowly than that of the control group.
It should be understood that the above-mentioned embodiments are only some examples of the present invention, and are not intended to limit the present invention, and any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A negative electrode material composition, the composition comprising: a lithium-carbon material, a conductive agent and a binder,
wherein the binder is a polymer having a molecular weight in the range of 104-106Has at least one of the following structures:
wherein X% represents the mass fraction of X structural units in the binder, Y% represents the mass fraction of Y structural units,
z% represents the mass fraction of Z structural units, and satisfies the following condition:
X％+Y％+Z％＝100％
0≤Z％≤33％
0≤X％≤35％
0≤Y％≤35％
X％+Y％≥Z％，
or
Wherein X '% represents the mass fraction of X' structural units in the binder, Y '% represents the mass fraction of Y' structural units, Z '% represents the mass fraction of Z' structural units, and L '% represents the mass fraction of L' structural units in the binder, satisfying:
X’％+Y’％+Z’％+L’％＝100％
0≤Z’％≤30％
0≤X’％≤40％
0≤Y’％≤40％
0≤L’％≤5％
X’％+Y’％≥Z’％
wherein: r0Is hydrogen or a hydrocarbyl or hydroxy group;
R1、R2、R3、R4、R5、R6、R7、R8、R9、R10is hydrogen or a hydrocarbyl group;
the constitutional units shown in parentheses may be arranged arbitrarily or in an ordered manner.
2. The negative electrode material composition according to claim 1, wherein the binder is contained in the negative electrode material composition in an amount of 0.1 to 10% by mass; and/or the lithium carbon material accounts for 80-95% of the negative electrode material composition by mass; and/or the conductive agent accounts for 0.1-10% of the negative electrode material composition in percentage by mass.
3. The negative electrode material composition of claim 1, wherein the lithium-carbon material is a composite material of carbon material microspheres and metallic lithium, wherein the carbon material microspheres are microspherical porous carbon skeletons formed by interlacing and agglomerating fibrous carbon nanomaterials, have D50 of 5-30 microns and pores of 5-50 nanometers, and the metallic lithium is filled in the pores and/or surfaces of the carbon material microspheres.
4. The negative electrode material composition of claim 3, wherein the carbon material microspheres further comprise an amide-based organic additive that is modified on the surface of the fibrous carbon nanomaterial and uniformly distributed inside and on the surface of the microspherical porous carbon skeleton; preferably, the amide organic additive is one or more organic polymers selected from polyacrylamide, polyvinylpyrrolidone, water-soluble polyamide resin, urea-formaldehyde resin and water-soluble polyurethane, or one or more small-molecule organic compounds selected from N-methylformamide, N, N-diethylformamide, N-methylacetamide, N, N, N ', N' -tetramethylurea and N-methylpyrrolidone.
5. The negative electrode material composition of claim 3, wherein the fibrous carbon nanomaterial is selected from one or more of single-walled carbon nanotubes, multi-walled carbon nanotubes, aminated carbon nanotubes, carboxylated carbon nanotubes, hydroxylated carbon nanotubes, nitrogen-doped carbon nanotubes, phosphorus-doped carbon nanotubes, carbon nanofibers, and graphitized carbon nanofibers.
6. The negative electrode material composition of claim 3, wherein the weight ratio of the carbon material microspheres and the metallic lithium in the lithium-carbon material is 1:0.1 to 1: 4.
7. The negative electrode material composition of claim 1, wherein the conductive agent comprises acetylene black, conductive graphite, Ketjen Black (KB), graphene, carbon nanotubes.
8. A slurry comprising the anode material composition according to any one of claims 1 to 7, further comprising a solvent, wherein the solvent is a non-polar or weakly polar solvent, and the solid content of the slurry is 10 to 40 mass%.
9. A lithium carbon material negative electrode comprising a current collector and a coating layer on a surface of the current collector, the coating layer being formed by coating and drying the slurry of claim 8.
10. A lithium ion battery comprising the lithium carbon material negative electrode according to claim 9.
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