CN113013390B - Negative plate and lithium ion battery - Google Patents

Negative plate and lithium ion battery Download PDF

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CN113013390B
CN113013390B CN202110191633.5A CN202110191633A CN113013390B CN 113013390 B CN113013390 B CN 113013390B CN 202110191633 A CN202110191633 A CN 202110191633A CN 113013390 B CN113013390 B CN 113013390B
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silicon
based material
negative electrode
graphite particles
coating layer
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CN113013390A (en
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薛佳宸
刘春洋
李素丽
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Zhuhai Cosmx Battery Co Ltd
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Zhuhai Cosmx Battery 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
    • H01M4/38—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
    • 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
    • H01M4/58—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
    • 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

Abstract

The invention provides a negative plate and a lithium ion battery. The negative electrode active layer of the negative electrode plate comprises a silicon-based material and graphite particles, wherein the silicon-based material comprises a functional silicon-based material, at least 3 graphite particles are arranged around the functional silicon-based material, and the distance between the graphite particles and the functional silicon-based material is 0.5-2 mu m. The lithium ion battery has high energy density, good cycle performance and safety performance, and is suitable for large-scale commercial application.

Description

Negative plate and lithium ion battery
Technical Field
The invention relates to a negative plate and a lithium ion battery, and belongs to the technical field of lithium ion batteries.
Background
With the rapid development of lithium ion batteries, the energy density of lithium ion batteries prepared by matching traditional Lithium Cobaltate (LCO), lithium iron phosphate (LFP), Nickel Cobalt Manganese (NCM) and Nickel Cobalt Aluminum (NCA) cathode materials with graphite cathode materials is far from meeting the market demand, so that it is necessary to develop a new cathode and anode system capable of improving the energy density of the lithium ion batteries.
The silicon-based negative electrode material has excellent performances of high specific capacity, low cost, easy processing and the like, so the silicon-based negative electrode material can replace a graphite negative electrode to obviously improve the energy density of a battery, and is a next-generation negative electrode material with a good application prospect.
However, the lithium intercalation mechanism of the silicon-based negative electrode material is different from that of an anisotropic graphite negative electrode material, the alloying process of the silicon-based negative electrode material is accompanied by very large isotropic expansion, and the silicon-based negative electrode material after the expansion in actual use can generate larger in-plane expansion of a pole piece, so that the internal stress of the negative pole piece is increased, the silicon-based negative electrode material is distorted and even tears a copper foil substrate, the cycle performance of a lithium ion battery is poor, and even the failure of a battery cell can be caused to cause a safety problem.
Disclosure of Invention
In view of the above drawbacks, the present invention provides a negative electrode sheet having low expansion performance and good cycle performance while having high energy density.
The invention also provides a lithium ion battery which has good cycle performance and safety performance under the condition of high energy density.
The first aspect of the embodiments of the present invention provides a negative electrode sheet, where the negative electrode sheet includes a current collector and a negative electrode active layer disposed on a functional surface of the current collector, and the negative electrode active layer includes a silicon-based material and graphite particles;
the silicon-based material comprises a functional silicon-based material, at least 3 graphite particles are arranged around the functional silicon-based material, and the distance between the graphite particles and the functional silicon-based material is 0.5-2 mu m.
The negative electrode tab as described above, wherein the silicon-based material comprises at least 50% of functional silicon-based material based on the total amount of the silicon-based material.
The negative electrode sheet as described above, wherein the number of graphite particles having a distance of 0.5 to 2 μm from the functional silicon-based material is 3 to 7.
The negative electrode plate as described above, wherein the silicon-based material comprises Li-SiOxA core, a carbon coating layer and an oxygen-containing salt coating layer, the Li-SiOxAt least part of the surface of the inner core is covered by the carbon coating layer, and at least part of the surface of the carbon coating layer is covered by the oxygen-containing salt coating layer, wherein 1.2 > X > 0.8.
The negative electrode sheet as described above, wherein the oxygen-containing salt coating layer further comprises a fluoride.
The negative electrode sheet as described above, wherein,in the silicon-based material, the mass percent of the carbon coating layer is 0.5-5%; the mass percentage of the oxygen-containing salt coating layer is 0.05-5%; the Li-SiOxThe mass percentage of the inner core is 90-99.45%.
The negative electrode sheet as described above, wherein the carbon coating layer has a thickness of 0.01 to 1 μm, and/or,
the thickness of the oxygen-containing salt coating layer is 0.01-1 μm.
The negative electrode sheet as described above, wherein the silicon-based material is 0.1 to 55% by mass and the graphite particles are 45 to 99.9% by mass, based on the total mass of the silicon-based material and the graphite particles.
The negative electrode sheet as described above, wherein the silicon-based material has a median particle diameter Dv50SiIs 2-15 μm, and/or,
the median particle diameter D of the graphite particlesv50GrIs 5-20 μm.
The negative electrode sheet as described above, wherein the graphite particles have a median particle diameter Dv50GrAnd a median particle diameter D of said silicon-based materialv50SiThe ratio of (A) to (B) is Dv50Gr/Dv50Si，1μm≤Dv50Gr/Dv50Si≤10μm。
The negative electrode sheet as described above, wherein the silicon-based material has a median particle diameter Dv90SiMedian particle diameter D of said silicon-based materialv10SiThe ratio of (A) to (B) is Dv90Si/Dv10Si，2μm≤Dv90Si/Dv10Si≤6μm。
The negative electrode sheet as described above, wherein the Li-SiOxThe inner core has a first characteristic peak in an X-ray diffraction pattern at 2 theta in a range of 26.5 DEG to 27.5 DEG, a second characteristic peak in a range of 18.5 DEG to 19.5 DEG, and a third characteristic peak in a range of 32.5 DEG to 33.5 deg.
The negative electrode plate as described above, wherein the highest intensity value of the first characteristic peak is I1The highest intensity value of the second characteristic peak is I2The maximum intensity value of the third characteristic peak is I3In which I1＞I2＞I3。
The negative plate as described above, wherein the silicon-based material has a specific surface area of 0.5-1m2(ii)/g; and/or the presence of a gas in the atmosphere,
the specific surface area of the graphite particles is 0.5-1.5m2/g。
A second aspect of the embodiments of the present invention provides a lithium ion battery, wherein the negative electrode sheet of the lithium ion battery is the above negative electrode sheet.
The negative electrode active layer of the negative electrode plate comprises a silicon-based material and graphite particles, wherein the silicon-based material comprises a functional silicon-based material, at least 3 graphite particles are arranged around the functional silicon-based material, and the distance between the graphite particles and the functional silicon-based material is 0.5-2 mu m. In the negative plate, because enough space is reserved between the functional silicon-based material and the graphite particles, when the functional silicon-based material expands, the expansion part can preferentially fill the space, so that the possibility of the silicon-based material expanding and extruding the graphite particles is reduced, the possibility of deformation of the negative plate is reduced, and the cycle stability and the safety performance of the lithium ion battery are improved.
The lithium ion battery provided by the invention has high energy density, first effect and quick charge capacity, has good cycle performance and safety performance, and is suitable for large-scale commercial application due to the negative plate.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the related art, the drawings used in the description of the embodiments of the present invention or the related art are briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
FIG. 1 is a surface Scanning Electron Microscope (SEM) photograph of a silicon-based material in example 1 of the present invention;
fig. 2 is a cross-sectional SEM picture of the negative electrode sheet in example 1 of the present invention;
fig. 3 is a cross-sectional SEM picture of the negative electrode sheet in comparative example 1 of the present invention;
FIG. 4 is an X-ray diffraction (XRD) spectrum of Li-SiOx in example 1 of the present invention;
FIG. 5 is a graph comparing the capacity retention after cycling of the lithium ion batteries in example 1 of the present invention and comparative example 5;
fig. 6 is a schematic view of a negative electrode sheet cycled 600 times in example 2 of the present invention;
fig. 7 is a schematic view of the negative electrode sheet according to comparative example 2 of the present invention, which was cycled 600 times.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
The first aspect of the invention provides a negative plate, which comprises a current collector and a negative active layer arranged on the functional surface of the current collector, wherein the negative active layer comprises a silicon-based material and graphite particles;
the silicon-based material comprises a functional silicon-based material, at least 3 graphite particles are arranged around the functional silicon-based material, and the distance between the graphite particles and the functional silicon-based material is 0.5-2 mu m.
It is understood that the functional silicon-based material of the present invention means a silicon-based material having a distance of 0.5 to 2 μm from the graphite particles and a distance of 0.5 to 2 μm from at least 3 graphite particles.
It should be noted that the distance in the present invention refers to the minimum distance between the graphite particles and the silicon-based material measured in at least three directions around the silicon-based material in the SEM image of the cross section of the negative electrode plate, and the angle between any two adjacent measurement directions is greater than 30 ° so as to ensure that the silicon-based material has sufficient expansion space in both the transverse and longitudinal directions. The number of graphite particles herein refers to the number of individual graphite particles, i.e., the number of primary graphite particles. If the graphite particles form agglomerates, calculatedThe number of graphite particles is the number of individual graphite particles in the agglomerate that meet the above requirements, rather than treating the agglomerate as one particle. In the present invention, if the silicon-based material having the agglomeration is used, the agglomeration of the silicon-based material having a distance of 0.5 to 2 μm from the graphite particle may be considered as the functional silicon-based material. And the compacted density of the anode active layer of the invention is not more than 2.0g/cm3。
When the silicon-based material expands in the process of pre-embedding lithium, because the distance between the functional silicon-based material and the graphite particles is 0.5-2 mu m, enough space is reserved between the functional silicon-based material and the graphite particles due to the arrangement of the distance, when the functional silicon-based material expands, the expansion part of the functional silicon-based material can firstly fill the space, and cannot directly extrude the graphite, so that the possibility of deformation of a negative plate caused by extrusion of the silicon-based material and the graphite is reduced, and the cycle stability and the safety performance of the lithium ion battery are improved. And at least 3 graphite particles are arranged at a distance of 0.5-2 mu m from the functional silicon-based material, and a distance is reserved between enough graphite particles and the functional silicon-based material, so that the expansion of the silicon-based material can be better relieved, and the safety performance of the lithium ion battery is improved.
In some embodiments of the invention, the silicon-based material comprises at least 50% functional silicon-based material based on the total amount of silicon-based material. Enough functional silicon-based materials can better lighten the internal stress of the negative plate when the silicon-based materials expand, and the cycle stability and the safety performance of the lithium ion battery are improved.
In some embodiments of the present invention, the number of graphite particles having a distance of 0.5 to 2 μm from the functional silicon-based material is 3 to 7.
It is understood that the distance between 3 to 7 graphite particles and the functional silicon-based material is 0.5 to 2 μm. When the silicon-based material expands in the process of pre-embedding lithium, only 3-7 graphite particles are arranged at the position of 0.5-2 mu m around the functional silicon-based material, and a small amount of graphite particles can not block the expansion of the functional silicon-based material, so that the possibility of the increase of the internal stress of the negative plate caused by the expansion of the silicon-based material can be reduced, the possibility of the deformation of the negative plate is reduced, and the cycle stability and the safety performance of the lithium ion battery are further improved.
In some embodiments of the invention, the silicon-based material comprises Li-SiOxCore, carbon coating layer and oxygen-containing salt coating layer, Li-SiOxAt least part of the surface of the inner core is covered by a carbon coating layer, and at least part of the surface of the carbon coating layer is covered by an oxygen salt-containing coating layer, wherein 1.2 > X > 0.8.
The silicon-based material of the invention is of a coating structure, wherein the inner core is Li-SiOx，Li-SiOxThe core has the advantage of long cycle life, and can be improved by including the Li-SiOxThe cycle performance of the silica-based material of the core further improves the cycle life of the lithium ion battery. Li-SiOxAt least part of the surface of the inner core is covered by the carbon coating layer, and the carbon material in the carbon coating layer can improve the conductivity of the silicon-based material, so that the quick charging capability of the lithium ion battery is improved. At least part of the surface of the carbon coating layer is coated by the oxysalt coating layer, the oxysalt coating layer can effectively improve the stability of the silicon-based material in water system slurry, reduce the affinity of the silicon-based material and water and reduce the water in the cathode slurry from entering Li-SiOxThe possibility of an inner core reduces the phenomenon of excessive gas production caused by the reaction of silicon-based materials and water, and water in the slurry of the negative electrode does not enter Li-SiOxAnd when the negative plate is dried, water in the negative slurry can be quickly volatilized, so that the water content of the negative plate is reduced, and the circulation stability of the lithium ion battery is improved. It is worth mentioning that Li-SiOxThe core not only has the advantages of long cycle life, but also has the advantages of high energy density and high first efficiency, so the Li-SiO-based composite material can be improvedxThe energy density and the first effect of the silicon-based material of the core are improved.
In the invention, the carbon coating layer can be coated on Li-SiOxThe whole outer surface of the inner core can be coated with Li-SiOxA portion of the outer surface of the inner core. The oxygen-containing salt coating layer can be coated on the whole outer surface of the carbon coating layer and can also be coated on part of the outer surface of the carbon coating layer. Wherein the thickness of the carbon coating layer and the oxy-salt coating layer may be uniform or non-uniform.
Specifically, the carbon coating layerThe carbon material in (3) may be selected from amorphous carbon or multilayer graphene. The oxysalt of the oxysalt coating layer may be LiSO4、LiCO3、ROCO2Li (R is selected from alkyl, such as C)1-6Alkyl group of (2), Al (PO)3)3、Y(PO3)3、La(PO3)3Or LiPO3At least one of (1). The graphite particles may be artificial graphite or natural graphite.
The negative active layer of the negative plate comprises the silicon-based material and the graphite particles, the silicon-based material comprises the functional silicon-based material, the number of the graphite particles around the functional silicon-based material is small, a certain distance is reserved between the functional silicon-based material and the graphite particles, and the functional silicon-based material is enough, so that the influence of expansion of the silicon-based material on the internal stress of the negative plate in the lithium pre-embedding process can be reduced, the condition that the negative substrate is distorted, deformed and even torn due to the increase of the internal stress of the negative plate is greatly avoided, and the cycle stability and the safety performance of the lithium ion battery are improved. In addition, when the coated silicon-based material is used for a lithium ion battery, the energy density, the first effect, the quick charge capacity and the cycle stability of the lithium ion battery can be improved.
In some embodiments of the present invention, the above-described oxy-salt coating may further comprise fluoride. Fluoride in the oxygen-containing salt coating layer is beneficial to the corrosion of the silicon-based material to HF in the electrolyte, the service life of the silicon-based material is further prolonged, and the cycle stability of the lithium ion battery is improved.
In particular, the above fluorides may be selected from LiF, LixPOyFz、LiaPFbWherein x, y and z satisfy the valence equilibrium of the compound, and a and b satisfy the valence equilibrium of the compound.
In some embodiments of the present invention, the carbon coating layer is 0.5 to 5% by mass in the silicon-based material; the mass percentage of the oxygen-containing salt coating layer is 0.05-5%; Li-SiOxThe mass percentage of the inner core is 90-99.45%.
In silicon-based materials, too high a mass percentage of the oxygen-containing salt coating may decreaseThe energy density of the lithium ion battery is low, the mass percentage of the oxygen-containing salt is too low, the stability of the silicon-based material in water system slurry is difficult to effectively improve, and the cycle stability of the lithium ion battery is not facilitated; similarly, the energy density of the lithium ion battery can be reduced due to the excessively high mass percentage of the carbon coating layer, and the conductivity of the carbon material cannot be fully exerted due to the excessively low mass percentage of the carbon coating layer, so that the quick charge performance of the lithium ion battery is not facilitated; furthermore, although in the silicon-based material, Li-SiOxThe mass percentage of the inner core is high, the energy density and the first effect of the lithium ion battery can be improved, but the Li-SiO brought with the energy density and the first effectxThe swelling phenomenon of the inner core is very serious, and the cycle performance and the safety performance of the lithium ion battery are reduced. Therefore, the invention reasonably arranges the carbon coating layer, the oxygen-containing salt coating layer and the Li-SiOxThe mass percentage of the inner core ensures that the prepared silicon-based material can be balanced by a carbon coating layer, an oxygen-containing salt coating layer and Li-SiOxThe positive influence and the negative influence brought by the inner core simultaneously ensure the energy density and the first effect of the lithium ion battery and improve the cycle performance, the quick charge capacity and the safety performance of the lithium ion battery.
Further, the thickness of the carbon coating layer is 0.01 to 1 μm, and the thickness of the oxygen salt-containing coating layer is 0.01 to 1 μm. In the silicon-based material, the carbon coating layer is too thin, so that the conductivity of the carbon material is difficult to fully play, and the quick charge performance of the lithium ion battery is not facilitated; similarly, the thickness of the oxygen-containing salt coating layer is too thin, so that the stability of a silicon-based material in water-based slurry is difficult to effectively improve, the cycle performance of the lithium ion battery is influenced, the thickness of the oxygen-containing salt is too thick, and the energy density of the prepared lithium ion battery is low.
The preparation method of the silicon-based material comprises the following steps:
1) coating carbon with Li-SiOxMaterial, organic solution containing oxysaltsMixing the agents, and dispersing to form a suspension solution;
2) drying the mixed solution in the step 1) to obtain the silicon-based material.
Specifically, carbon-coated Li-SiO in step 1)xThe material may be commercially available as long as the carbon material in the carbon coating layer satisfies the definition of the carbon material described above.
The organic solvent in step 1) can be N-methylpyrrolidone (NMP), ethanol, acetone or toluene.
The mass percentage of the oxy-salt in step 1) is 0.05-5% based on the total mass of the silicon-based material.
The drying method in step 2) is not particularly limited, and all methods that can dry the mixed solution in step 1) are within the scope of the present invention, and in a specific embodiment, the drying method in step 2) is a spray drying method.
The preparation method of the silicon-based material can further comprise the following steps: 3) the silicon-based material coated with the oxygen-containing salt is contacted with fluorine-containing electrolyte after being formed, and the silicon-based material with the oxygen-containing salt layer and fluoride is prepared and obtained after reaction.
In some embodiments of the invention, the mass percent of the silicon-based material is 0.1-55% and the mass percent of the graphite particles is 45-99.9%, based on the total mass of the silicon-based material and the graphite particles. It can be understood that the mass percentages of both the silicon-based material and the graphite particles in the total mass of the silicon-based material and the graphite particles show opposite tendencies, i.e., as the mass percentage of the silicon-based material in the total mass of the silicon-based material and the graphite particles decreases, the mass percentage of the graphite particles in the total mass of the silicon-based material and the graphite particles increases; when the mass percentage content of the silicon-based material in the total mass of the silicon-based material and the graphite particles increases, the mass percentage content of the graphite particles in the total mass of the silicon-based material and the graphite particles decreases. Although the larger the mass percentage content of the silicon-based material is, the better the first effect and the energy density of the lithium ion battery are improved, the expansion phenomenon and the agglomeration phenomenon of the silicon-based material brought along with the mass percentage content of the silicon-based material are also very serious, and the cycle performance and the safety performance of the lithium ion battery are not facilitated. Therefore, the mass percentage of the silicon-based material and the graphite particles in the total mass of the silicon-based material and the graphite particles is reasonably set, more functional silicon-based materials are formed in the negative electrode active layer, the possibility of the increase of the internal stress of the negative electrode plate caused by the expansion of the silicon-based material in the lithium intercalation process can be effectively improved on the premise that the energy density and the first effect of the lithium ion battery are satisfactory, and the cycle performance and the safety performance of the lithium ion battery are improved.
Further, the median particle diameter D of the above silicon-based materialv50Si2-15 μm, the median particle diameter D of the graphite particlesv50GrIs 5-20 μm.
In the present invention, Dv50SiThe particle diameter corresponding to 50% of the cumulative volume percentage of the silicon-based material, Dv50GrThe particle size is the particle size corresponding to the cumulative volume percentage of the graphite particles reaching 50%. According to the invention, the proper median particle size of the silicon-based material and the proper median particle size of the graphite particles are selected, so that more functional silicon-based materials can be formed in the negative electrode active layer, and the more the functional silicon-based materials are, the more the influence of the expansion of the silicon-based materials in the lithium pre-intercalation process on the negative electrode plate can be overcome, and the cycle performance and the safety performance of the lithium ion battery can be improved.
In some embodiments of the present invention, the median particle diameter D of the graphite particles may be further set for more formation of the functional silicon-based materialv50GrAnd median particle diameter D of silicon-based materialv50SiThe proportional relationship between them. Specifically, the median diameter D of the graphite particlesv50GrAnd median particle diameter D of silicon-based materialv50SiThe ratio of D to Dv50Gr/Dv50Si，1μm≤Dv50Gr/Dv50Si≤10μm。
In some embodiments of the invention, the silicon-based material has a particle size Dv90SiParticle size D with silicon-based materialsv10SiThe ratio of (A) to (B) is Dv90Si/Dv10Si，2μm≤Dv90Si/Dv10Si≤6μm。
In the present invention, Dv90SiThe grain diameter corresponding to the silicon-based material when the cumulative volume percentage reaches 90 percent; dv10SiCumulative volume percent for silicon-based materialsThe particle size corresponding to 10% is obtained. According to the invention, the particle size of the silicon-based material is further controlled, so that more functional silicon-based materials can be formed in the negative electrode active layer, the influence of the expansion of the silicon-based materials in the pre-lithium-embedding process on the negative electrode piece can be overcome, and the cycle performance and the safety performance of the lithium ion battery can be improved.
In some embodiments of the invention, the Li-SiOxThe inner core has a first characteristic peak in an X-ray diffraction pattern at 2 theta within a range of 26.5 DEG to 27.5 DEG, a second characteristic peak in a range of 18.5 DEG to 19.5 DEG and a third characteristic peak in a range of 32.5 DEG to 33.5 deg.
In some embodiments of the invention, the first characteristic peak maximum intensity value is I1The maximum intensity value of the second characteristic peak is I2The maximum intensity value of the third characteristic peak is I3In which I1＞I2＞I3。
In some embodiments of the present invention, the silicon-based material has a specific surface area of 0.5 to 1m in order to form more functional silicon-based materials2(iv) g; the specific surface area of the graphite particles is 0.5-1.5m2/g。
The preparation method of the negative plate comprises the following steps:
1) mixing a silicon-based material with graphite particles, a negative electrode binder, a negative electrode conductive agent and an additive, adding deionized water into the mixed system, and stirring at the temperature of 20-45 ℃ for 6-18h to prepare negative electrode slurry with the solid content of 30-50%;
2) and coating the prepared negative slurry on at least one functional surface of a negative current collector, drying and rolling to form a negative active layer on the surface of the negative current collector, thus preparing a negative plate.
The invention is not limited to the stirring mode in step 1), and any mode capable of stirring the mixed system falls within the protection scope of the invention, and in a specific embodiment, the stirring mode of the invention can be at least one of stirring by using a stirring kettle or stirring by using a vacuum stirrer.
Specifically, step 2)The coating thickness of the negative electrode slurry on the surface of the negative electrode current collector is 20-100 mu m; the compacted density of the negative electrode active layer is not more than 2.0g/cm3(ii) a The negative electrode current collector may be a copper foil or a porous copper foil.
The negative electrode slurry comprises the following components in percentage by mass: 78-99.3% of silicon-based material and graphite particles, 0.1-10% of negative electrode conductive agent, 0.1-10% of negative electrode binder and 0.5-3% of additive. According to the invention, through reasonably setting the composition of the negative electrode slurry, the negative electrode plate containing more functional silicon-based materials can be prepared, so that the cycle performance of the negative electrode plate is better, and the cycle performance of the lithium ion battery is further improved.
In a specific embodiment, the negative electrode slurry comprises the following components in percentage by mass: 88-97% of silicon-based material and graphite particles, 1-5% of negative electrode conductive agent, 1-5% of negative electrode binder and 1-2% of additive.
The negative electrode conductive agent may be at least one selected from conductive carbon black, carbon fiber, activated carbon, acetylene black, graphene, and carbon nanotubes. The negative electrode binder may be at least one selected from styrene butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyurethane, polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, alginic acid, sodium alginate, sodium carboxymethylcellulose (CMC-Na), lithium carboxymethylcellulose (CMC-Li), and polyvinylpyrrolidone (PVP). The additive may be selected from at least one of EC, DEC or PEO.
Further, the additive includes ethylene carbonate. In the negative electrode slurry, the ethylene carbonate is coated on the surfaces of the silicon-based material and the graphite particles, and when the negative electrode plate is dried, an ethylene carbonate solvent coated on the surfaces of the silicon-based material and the graphite particles is volatilized, so that pores are formed between the silicon-based material and the graphite particles, more functional silicon-based materials are formed in the negative electrode active layer, the possibility of damaging the negative electrode plate due to expansion of the silicon-based material in the lithium pre-embedding process is reduced, and the cycle performance and the safety performance of the lithium ion battery are improved.
The particle size of the silicon-based material with the carbon coating layer and the oxygen-containing salt coating layer is regulated, and the particle size of graphite particles is regulated; and mixing the silicon-based material, the graphite particles, the negative binder, the negative conductive agent, the additive and deionized water to obtain negative slurry, and coating the negative slurry on the functional surface of the current collector to form a negative plate. The number of graphite particles which are 0.5 to 2 mu m away from the functional silicon-based material in the negative plate is at least 3.
In a second aspect of the present invention, a lithium ion battery is provided, where the negative electrode sheet of the lithium ion battery is the negative electrode sheet described above.
In a specific embodiment, the lithium ion battery further comprises a positive electrode sheet, a separator and an electrolyte. The positive active material in the positive plate can be at least one selected from lithium iron phosphate, lithium manganese phosphate, lithium vanadium phosphate, lithium iron silicate, lithium cobaltate, nickel cobalt manganese ternary material, nickel manganese/cobalt manganese/nickel cobalt binary raw material, lithium manganate or lithium-rich manganese-based material. The separator may be at least one selected from a polyethylene polymer, a polypropylene polymer, and a nonwoven fabric.
The electrolyte is a non-aqueous electrolyte, and the non-aqueous electrolyte comprises a carbonate solvent and a lithium salt, wherein the carbonate solvent can be at least one selected from Ethylene Carbonate (EC), Propylene Carbonate (PC), diethyl carbonate (DEC), fluoroethylene carbonate (FEC), dimethyl carbonate (DMC) or Ethyl Methyl Carbonate (EMC); the lithium salt may be selected from LiPF6、LiBF4、LiSbF6、LiClO4、LiCF3SO3、LiAlO4、LiAlCl4、Li(CF3SO2)2N, LiBOB or lithium difluoroborate (LiDFOB).
The lithium ion battery provided by the invention has good cycle performance and safety performance due to the negative plate.
The lithium ion battery of the present invention can be used as a driving source and/or an energy storage source for electronic equipment.
The electronic device may include, but is not limited to, a mobile or fixed terminal having a battery, such as a mobile phone, a tablet computer, a notebook computer, an ultra-mobile personal computer (UMPC), a handheld computer, an intercom, a netbook, a POS machine, a Personal Digital Assistant (PDA), a wearable device, a virtual reality device, and the like.
The electronic equipment of the invention takes the lithium ion battery as the driving source and/or the energy storage source, so the endurance and the service life are excellent, and the user satisfaction is high.
Hereinafter, the negative electrode sheet and the lithium ion battery of the present invention will be described in detail by specific examples.
Example 1
The preparation method of the negative plate of the embodiment comprises the following steps:
1) coating purchased carbon with Li-SiO1.07The material is put into Al (PO)3)3Stirring the nano suspension for 60min, drying the mixed system, and then filtering to obtain a silicon-based material;
wherein, 2.6 wt% of Al (PO)3)3The nanosuspensions were obtained commercially.
Respectively cladding carbon with Li-SiO1.07The material and the silicon-based material were weighed, and the difference was calculated to obtain a coating layer containing the above-mentioned oxygen-containing salt in an amount of 0.5% by mass based on the total mass of the silicon-based material. Particle diameter D of the above silicon-based materialv10Si5.8 μm, Dv50SiIs 9 μm, Dv90SiAnd was 15 μm.
The surface morphology of the silicon-based material was observed by SEM, and fig. 1 is a surface SEM image of the silicon-based material in example 1 of the present invention, and it can be seen from fig. 1 that the surface of the silicon-based material is a smooth surface with bright edges.
2) Mixing the silicon-based material and the graphite particles obtained in the step 1) according to a mass ratio of 10:90, and mixing the silicon-based material and the graphite particles, Styrene Butadiene Rubber (SBR), sodium carboxymethylcellulose (CMC-Na), conductive carbon black (SP), single-walled carbon nanotubes (SWCNTs) and Ethylene Carbonate (EC) according to the total mass of the silicon-based material and the graphite particles: SBR: CMC-Na: SP: mixing SWCNTs with the mass ratio of 95:1.5:1.5:0.45:0.05:1.5, adding deionized water, and stirring for 10 hours at 35 ℃ under the action of a vacuum stirrer to obtain negative electrode slurry with the solid content of 40%;
wherein the graphite particles have a median particle diameter Dv50GrAnd 15 μm.
3) And uniformly coating the negative electrode slurry on a copper foil with the thickness of 8 micrometers, wherein the coating thickness of the negative electrode slurry on the surface of the copper foil is 50 micrometers, airing the copper foil coated with the negative electrode slurry at room temperature, transferring the copper foil to an oven with the temperature of 80 ℃ for drying for 10 hours, and then carrying out cold pressing and slitting to obtain the negative electrode plate.
And observing the cross section of the negative plate by adopting SEM to obtain the distance between the silicon-based material and the graphite particles, and determining the quantity percentage of the functional silicon-based material. Fig. 2 is a cross-sectional SEM image of the negative electrode sheet in example 1 of the present invention. As can be seen from FIG. 2, the number of graphite particles spaced 0.5 to 2 μm from the functional silicon-based material in the negative electrode sheet in example 1 was 3.
Example 2
The preparation method of the negative plate of the embodiment comprises the following steps:
1) coating purchased carbon with Li-SiO1.04The material being placed in La (PO)3)3Stirring the nano suspension for 60min, drying the mixed system, and then filtering to obtain a silicon-based material;
wherein, 3.1 wt% of La (PO)3)3The nanosuspensions were obtained commercially.
Respectively cladding carbon with Li-SiO1.04The material and the silicon-based material were weighed and the difference was calculated to obtain a coating layer containing the above-mentioned oxygen-containing salt in an amount of 0.5% by mass based on the total mass of the silicon-based material. Particle diameter D of the above silicon-based materialv10SiIs 4.2 μm, Dv50SiIs 5.9 μm, Dv90SiWas 10.4 μm.
2) Mixing the silicon-based material and the graphite particles in the step 1) according to a mass ratio of 15:85, and mixing the silicon-based material and the graphite particles, Styrene Butadiene Rubber (SBR), sodium carboxymethylcellulose (CMC-Na), conductive carbon black (SP), single-walled carbon nanotubes (SWCNTs) and EC according to the total mass of the silicon-based material and the graphite particles: SBR: CMC-Na: SP: mixing SWCNTs at a mass ratio of 94.5:1.5:1.5:0.45:0.05:2, adding deionized water, and stirring for 10 hours at 35 ℃ under the action of a vacuum stirrer to obtain negative electrode slurry with 42% of solid content;
wherein the graphite particles have a median particle diameter Dv50GrAnd 16 μm.
3) And uniformly coating the negative electrode slurry on a copper foil with the thickness of 8 micrometers, wherein the coating thickness of the negative electrode slurry on the surface of the copper foil is 40 micrometers, airing the copper foil coated with the negative electrode slurry at room temperature, transferring to an oven with the temperature of 80 ℃ for drying for 10 hours, and then cold-pressing and slitting to obtain the negative electrode sheet.
Comparative example 1
The preparation method of the negative electrode sheet in the present example is substantially the same as that in example 1, except that step 2) is different:
silicon-based materials, graphite particles, Styrene Butadiene Rubber (SBR), sodium carboxymethylcellulose (CMC-Na), conductive carbon black (SP) and single-walled carbon nanotubes (SWCNTs) are mixed according to the total mass of the silicon-based materials and the graphite particles: SBR: CMC-Na: SP: mixing SWCNTs with the mass ratio of 96.5:1.5:1.5:0.45:0.05, adding deionized water, and stirring at 35 ℃ for 10 hours under the action of a vacuum stirrer to obtain negative pole slurry with the solid content of 43.3%.
Fig. 3 is a cross-sectional SEM image of the negative electrode sheet in comparative example 1 of the present invention. As can be seen from fig. 3, the silicon-based material and the graphite particles in comparative example 1 are closely adjacent, and the silicon-based material has 1 graphite particle around it.
Comparative example 2
The preparation method of the negative electrode sheet in this example is substantially the same as that in example 2, the only difference being that step 2) is different:
silicon-based materials, graphite particles, Styrene Butadiene Rubber (SBR), sodium carboxymethylcellulose (CMC-Na), conductive carbon black (SP) and single-walled carbon nanotubes (SWCNTs) are mixed according to the total mass of the silicon-based materials and the graphite particles: SBR: CMC-Na: SP: mixing SWCNTs with the mass ratio of 96.5:1.5:1.5:0.45:0.05, adding deionized water, and stirring at 35 ℃ for 10 hours under the action of a vacuum stirrer to obtain negative pole slurry with the solid content of 42.3%.
Comparative example 3
The preparation method of the negative electrode sheet in this comparative example was substantially the same as that in example 1, except that step 2) was different:
coating purchased carbon with Li-SiO1.07Material and graphiteThe particles are mixed according to a mass ratio of 10: 90.
Comparative example 4
The preparation method of the negative electrode sheet in this comparative example was substantially the same as that in example 2, except that step 2) was different:
coating purchased carbon with Li-SiO1.04The matrix and the graphite particles are mixed according to the mass ratio of 15: 85.
Comparative example 5
The preparation method of the negative electrode sheet in this comparative example was substantially the same as that in example 1, except that step 2) was different: particle diameter D of silicon-based Materialv10Si0.3 μm, Dv50Si1.5 μm, Dv90SiIt was 3.7 μm.
Test examples
The negative electrode sheets of the above examples and comparative examples were respectively prepared into lithium ion batteries according to the following methods:
1) preparation of positive plate
According to the preparation method, the positive electrode active materials of Lithium Cobaltate (LCO), polyvinylidene fluoride (PVDF), conductive carbon black (SP) and Carbon Nano Tubes (CNTs) are prepared according to the following steps of: PVDF: SP: mixing CNTs according to the mass ratio of 96:2:1.5:0.5, adding N-methyl pyrrolidone (NMP), stirring under the action of a vacuum stirrer at the temperature of 25 ℃ for 6 hours, and mixing to obtain uniform and flowable anode active slurry;
uniformly coating the positive active slurry on an aluminum foil with the thickness of 12 mu m, baking the coated aluminum foil in 5 sections of baking ovens with different temperature gradients, drying the aluminum foil in a 120 ℃ baking oven for 8 hours, and then rolling and slitting to obtain a required positive plate;
and the size of the negative pole piece is larger than that of the positive pole piece, and the reversible capacity of the unit area is 6% higher than that of the positive pole.
2) Preparation of electrolyte
In a glove box filled with argon gas to a satisfactory water oxygen content, 13 wt% of fully dried lithium hexafluorophosphate (LiPF) was rapidly added to Ethylene Carbonate (EC)6) And uniformly stirring, and obtaining the required electrolyte after the water and free acid are detected to be qualified.
3) Diaphragm
An 8 μm thick polyethylene separator was selected, and supplied by Asahi Kasei corporation.
4) Preparation of lithium ion battery
Stacking the prepared positive plate, the diaphragm and the negative plates prepared in the embodiment and the comparative example in sequence, ensuring that the diaphragm plays a role in isolating the positive plate from the negative plate, and then winding to obtain a bare cell;
and (3) placing the bare cell in an outer packaging foil, injecting the prepared electrolyte into the outer packaging foil, and carrying out vacuum packaging, standing, formation, shaping and sorting to obtain the required lithium ion battery.
Correlation data characterization
1. For Li-SiO of example 1xXRD test was conducted
FIG. 4 shows Li-SiO in example 1 of the present inventionxAs shown in fig. 4, the silicon-based material of the present invention had characteristic peaks in the X-ray diffraction pattern assigned to 2 θ of 26.5 ° to 27.5 °, assigned to 18.5 ° to 19.5 °, assigned to 32.5 ° to 33.5 °, and assigned to 21.5 ° to 22.5 °. Wherein the highest intensity value of 2 theta in the X-ray diffraction pattern is I within the range of 26.5-27.5 DEG2The highest intensity value falling within the range of 18.5 DEG to 19.5 DEG is I3The highest intensity value falling within the range of 32.5 DEG to 33.5 DEG is I4，I2>I3>I4。
2. Determination of the number of graphite particles in the range of 0.5-2 μm of silicon-based material and the percentage of the number of functional silicon-based material
SEM was selected to perform SEM tests on the cross sections of the negative electrode sheets in the examples and comparative examples. The number of graphite particles in the range of 0.5 to 2 μm of the silicon-based material and the number percentage of the functional silicon-based material were calculated from the SEM images.
The test method is as follows:
polishing the section of the negative plate by Ar particles, then shooting at least 40 silicon-based materials which are 5 microns away from the current collector or the surface of the negative plate by adopting SEM (scanning electron microscope), respectively recording the number of graphite particles which are within a range of 0.5-2 microns away from the silicon-based materials, and calculating the percentage of the silicon-based materials which meet the graphite particle number of 3-7 in the at least 40 silicon-based materials, namely the percentage of the functional silicon-based materials.
3. Testing of water content of negative plate before liquid injection
The water content of the negative plate before liquid injection adopts a test method commonly used in the field. The test results are shown in Table 1.
4. Capacity retention after 0.5C cycle 600 times/300 times
The testing steps are as follows: at normal temperature, charging the lithium ion battery to 4.45V at a constant current and a constant voltage of 0.5C, cutting off 0.05C, discharging the lithium ion battery to 3.0V at 0.5C, cutting off the lithium ion battery, circulating for 600 times/300 times, calculating the capacity retention rate after 600 times/300 times of circulation, and calculating through the following formula, wherein the test result is shown in Table 1;
capacity retention ═ termination capacity/initial capacity 100%.
Fig. 5 is a graph comparing capacity retention rates after cycling of the lithium ion batteries in example 1 of the present invention and comparative example 5. As shown in fig. 5, the capacity retention rate after 600 cycles of the lithium ion battery of example 1 of the present invention is similar to the capacity retention rate after 300 cycles of the lithium ion battery of comparative example 5, which indicates that the cycle performance of the lithium ion battery of example 1 is better than that of the lithium ion battery of comparative example 5.
5. 0.5C cycle 600/300 post-expansion ratio
The testing steps are as follows: expansion ratio of (T)1-T0)/T 0100% of the total weight; 600g PPG initial 3.85V cell thickness T1Full-charged cell thickness T after 600 times/300 times0. The test results are shown in Table 1.
6. Morphology of negative electrode sheets in example 2 and comparative example 2 after 600 cycles
The negative electrode sheets of example 2 and comparative example 2 were photographed using a camera after 600 cycles to obtain the morphology of the negative electrode sheets of example 2 and comparative example 2.
Fig. 6 is a schematic view of a negative electrode sheet cycled 600 times in example 2 of the present invention; fig. 7 is a schematic diagram of the negative electrode sheet of comparative example 2 which is cycled 600 times, and as can be seen from fig. 6 and fig. 7, after the batteries of example 2 and comparative example 2 are disassembled, it is found that the negative electrode sheet of example 2 is kept complete, and the copper foil of the negative electrode sheet of comparative example 2 is torn, so that the invention can effectively reduce the stress in the plane of the negative electrode material in the cycle process, and reduce the safety risk of the battery.
TABLE 1
Figure BDA0002945370490000151
Figure BDA0002945370490000161
As can be seen from table 1, the cycle performance of the lithium ion battery prepared in the example of the present invention is superior to that of the lithium ion battery prepared in the comparative example, and the expansion rate of the negative electrode sheet prepared in the example of the present invention is lower than that of the negative electrode sheet prepared in the comparative example. Therefore, the negative plate prepared by the invention has low expansion rate and high cycle stability of the lithium ion battery because the functional silicon-based material in the negative plate has at least 3 graphite particles at the position with the distance of 0.5-2 mu m.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and these modifications or substitutions do not depart from the spirit of the corresponding technical solutions of the embodiments of the present invention.

Claims (11)

1. The negative plate is characterized by comprising a current collector and a negative active layer arranged on the surface of the current collector, wherein the negative active layer comprises a silicon-based material and graphite particles;
the silicon-based material comprises a functional silicon-based material, at least 3 graphite particles are arranged around the functional silicon-based material, and the distance between the graphite particles and the functional silicon-based material is 0.5-2 mu m;
the silicon-based material comprises Li-SiOxA core, a carbon coating layer and an oxygen-containing salt coating layer, the Li-SiOxAt least part of the surface of the inner core is covered by the carbon coating layer, and at least part of the surface of the carbon coating layer is covered by the oxygen-containing salt coating layer, wherein 1.2 > X > 0.8;
particle diameter D of the silicon-based materialv90SiWith the particle diameter D of said silicon-based materialv10SiThe ratio of (A) to (B) is Dv90Si/Dv10Si，2≤Dv90Si/Dv10Si≤6；
The specific surface area of the silicon-based material is 0.5-1m2/g；
The specific surface area of the graphite particles is 0.5-1.5m2/g；
Median particle diameter D of the silicon-based materialv50SiIs 2-15 μm;
the median particle diameter D of the graphite particlesv50GrIs 5-20 μm;
the distance between the graphite particles and the functional silicon-based material is the minimum value of the distances between the graphite particles and the silicon-based material measured in at least three directions around the silicon-based material in a cross-sectional scanning electron microscope picture of the negative plate, and the angle between any two adjacent measuring directions is larger than 30 degrees.
2. The negative electrode sheet according to claim 1, wherein the silicon-based material comprises at least 50% of functional silicon-based material based on the total amount of the silicon-based material.
3. The negative electrode sheet according to claim 1, wherein the oxygen-containing salt coating layer further comprises a fluoride.
4. The negative electrode sheet according to any one of claims 1 to 3, wherein the carbon coating layer is present in the silicon-based material in an amount of 0.5 to 5% by mass; the mass percentage of the oxygen-containing salt coating layer is 0.05-5%; the Li-SiOxThe mass percentage of the inner core is 90-99.45%.
5. The negative electrode sheet according to any one of claims 1 to 3, wherein the carbon coating layer has a thickness of 0.01 to 1 μm; and/or the presence of a gas in the atmosphere,
the thickness of the oxygen-containing salt coating layer is 0.01-1 μm.
6. The negative electrode sheet according to claim 4, wherein the carbon coating layer has a thickness of 0.01 to 1 μm; and/or the presence of a gas in the gas,
the thickness of the oxygen-containing salt coating layer is 0.01-1 μm.
7. The negative electrode sheet according to any one of claims 1 to 3 and 6, wherein the mass percentage of the silicon-based material is 0.1 to 55% and the mass percentage of the graphite particles is 45 to 99.9%, based on the total mass of the silicon-based material and the graphite particles.
8. Negative electrode sheet according to claim 7, wherein the graphite particles have a median particle diameter Dv50GrAnd the median particle diameter D of said silicon-based materialv50SiThe ratio of (A) to (B) is Dv50Gr/Dv50Si，1≤Dv50Gr/Dv50Si≤10。
9. The negative electrode sheet according to any one of claims 1, 2, 3, 6 and 8, wherein the Li-SiO is presentxThe inner core has a first characteristic peak at 2 theta in the range of 26.5 to 27.5 degrees, a second characteristic peak at 2 theta in the range of 18.5 to 19.5 degrees, and a third characteristic peak at 2 theta in the range of 32.5 to 33.5 degrees in the X-ray diffraction pattern.
10. The negative electrode sheet of claim 9, wherein the first characteristic peak maximum intensity value is I1The maximum intensity value of the second characteristic peak is I2The maximum intensity value of the third characteristic peak is I3In which I1＞I2＞I3。
11. A lithium ion battery, characterized in that the negative electrode sheet of the lithium ion battery is the negative electrode sheet according to any one of claims 1 to 10.
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CN116885105A (en) * 2021-09-08 2023-10-13 珠海冠宇电池股份有限公司 Lithium ion battery and electronic device of silicon negative electrode system
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103618086A (en) * 2013-11-21 2014-03-05 封锡胜 Positive material of lithium ion battery
CN107749490A (en) * 2017-09-18 2018-03-02 深圳市沃特玛电池有限公司 A kind of lithium ion battery

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1913200B (en) * 2006-08-22 2010-05-26 深圳市贝特瑞电子材料有限公司 Silicon carbone compound negative polar material of lithium ion battery and its preparation method
CN106058181A (en) * 2016-07-06 2016-10-26 上海交通大学 Preparation method of graphene-supported carbon-coated silicone nanoparticle composite electrode material
KR102377948B1 (en) * 2018-05-18 2022-03-22 삼성에스디아이 주식회사 Negative active material for rechargeable lithium battery and rechargeable lithium battery including same
CN111146410B (en) * 2018-11-05 2021-03-02 宁德时代新能源科技股份有限公司 Negative electrode active material and battery
CN112349900A (en) * 2019-08-07 2021-02-09 珠海冠宇电池股份有限公司 Negative pole piece and lithium ion battery containing same
CN111029543B (en) * 2019-11-28 2022-02-15 宁德新能源科技有限公司 Negative electrode material, and electrochemical device and electronic device comprising same
CN110931742B (en) * 2019-11-28 2021-03-02 宁德新能源科技有限公司 Negative electrode, and electrochemical device and electronic device comprising same
CN111653738B (en) * 2020-04-20 2022-01-07 万向一二三股份公司 Silicon-carbon negative electrode material of lithium ion battery and preparation method thereof
CN111916662A (en) * 2020-09-10 2020-11-10 珠海冠宇电池股份有限公司 Negative active material, negative pole piece comprising negative active material and lithium ion battery

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103618086A (en) * 2013-11-21 2014-03-05 封锡胜 Positive material of lithium ion battery
CN107749490A (en) * 2017-09-18 2018-03-02 深圳市沃特玛电池有限公司 A kind of lithium ion battery

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
"粒径级配对石墨基负极材料电化学性能的影响";张鑫等;《电源技术》;20200320(第03期);第318-321页 *

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