CN113540426A - Negative electrode material, and electrochemical device and electronic device comprising same - Google Patents

Abstract

The present application relates to an anode material, and an electrochemical device and an electronic device including the same. The negative electrode material comprises silicon-based particles and graphite particles, wherein the average sphericity of the graphite particles is A, the average sphericity of the silicon-based particles is B, and A and B satisfy the following conditions: B-A is more than 0 and less than or equal to 0.3. The cathode material has good cycle performance, and meanwhile, a battery prepared from the cathode material has good rate performance and low deformation rate.

Description

Negative electrode material, and electrochemical device and electronic device comprising same

The present application is a divisional application of an invention patent application having an application date of 2019, 11/28, and an application number of 201911194865.5, entitled "anode material and electrochemical device and electronic device including the same".

Technical Field

The application relates to the field of energy storage, in particular to a negative electrode material, an electrochemical device and an electronic device comprising the same, and particularly relates to a lithium ion battery.

Background

With the popularization of consumer electronics products such as notebook computers, mobile phones, tablet computers, mobile power sources, unmanned aerial vehicles and the like, the requirements on electrochemical devices therein are becoming stricter. For example, batteries are required not only to be lightweight but also to have high capacity and long operating life. Lithium ion batteries have already occupied a mainstream status in the market by virtue of their outstanding advantages of high energy density, high safety, no memory effect, long operating life, and the like.

Disclosure of Invention

Embodiments of the present application provide an anode material in an attempt to solve at least some of the problems presented in the related art. The embodiment of the application also provides an electrochemical device and an electronic device using the cathode.

In one embodiment, the present application provides an anode material comprising silicon-based particles and graphite particles, wherein the graphite particles have an average sphericity of a, the silicon-based particles have an average sphericity of B, a and B satisfy: B-A is more than 0 and less than or equal to 0.3.

In another embodiment, the present application provides an anode comprising an anode material according to embodiments of the present application.

In another embodiment, the present application provides an electrochemical device comprising an anode according to embodiments of the present application.

In another embodiment, the present application provides an electronic device comprising an electrochemical device according to an embodiment of the present application.

The battery obviously improves the cycle performance and the deformation rate of the battery by limiting the sphericity of the silicon-based particles and the graphite particles from the basis of reasonable matching between the silicon-based materials and the graphite materials.

Additional aspects and advantages of embodiments of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of embodiments of the present application.

Drawings

Drawings necessary for describing embodiments of the present application or the prior art will be briefly described below in order to describe the embodiments of the present application. It is to be understood that the drawings in the following description are only some of the embodiments of the present application. It will be apparent to those skilled in the art that other embodiments of the drawings can be obtained from the structures illustrated in these drawings without the need for inventive work.

FIG. 1A shows silicon oxide SiO in example 1_xScanning Electron Microscope (SEM) pictures of (a); fig. 1B shows an SEM picture of the graphite particles in example 1; fig. 1C shows an SEM picture of a partial cross section of the anode in example 1.

FIG. 2A shows silicon oxide SiO in example 1_xThe particle size distribution curve of (a); and fig. 2B shows a particle size distribution curve of graphite in example 1.

Fig. 3A is a cycle decay curve for the lithium ion batteries of example 1 and comparative example 1; fig. 3B is a deformation curve of the batteries of example 1 and comparative example 1; fig. 3C is an X-ray diffraction (XRD) pattern of the negative active material in example 10; and fig. 3D is an X-ray diffraction pattern of the negative electrode active material in comparative example 4.

Fig. 4 shows a schematic structural view of an anode active material according to an embodiment of the present application.

Fig. 5 shows a schematic view of the structure of a negative active material according to another embodiment of the present application.

Detailed Description

Embodiments of the present application will be described in detail below. The embodiments of the present application should not be construed as limiting the present application.

As used in this application, the term "about" is used to describe and illustrate minor variations. When used in conjunction with an event or circumstance, the terms can refer to instances where the event or circumstance occurs precisely as well as instances where the event or circumstance occurs in close proximity. For example, when used in conjunction with numerical values, the term can refer to a range of variation that is less than or equal to ± 10% of the stated numerical value, such as less than or equal to ± 5%, less than or equal to ± 4%, less than or equal to ± 3%, less than or equal to ± 2%, less than or equal to ± 1%, less than or equal to ± 0.5%, less than or equal to ± 0.1%, or less than or equal to ± 0.05%.

In the present application, Dv50 is the particle diameter corresponding to 50% of the cumulative volume percentage of the negative electrode active material, and is expressed in μm.

In the present application, Dn10 is a particle diameter in μm corresponding to the cumulative percentage of the amount of the negative electrode active material of 10%.

In the present application, the silicon compound contains elemental silicon, a silicon compound, a mixture of elemental silicon and a silicon compound, or a mixture of different silicides.

In this application, sphericity refers to the ratio of the shortest diameter to the longest diameter of a particle.

In the present application, the "gram capacity of the anode" refers to the gram capacity of the anode active material used to prepare the anode. For example, if the negative active material of the embodiment of the present application is a mixture of graphite and a silicon-based negative active material, the "negative gram capacity" refers to the gram capacity of the mixture.

Additionally, amounts, ratios, and other numerical values are sometimes presented herein in a range format. It is to be understood that such range format is used for convenience and brevity, and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited.

In the detailed description and claims, a list of items connected by the terms "one of," "one of," or other similar terms may mean any one of the listed items. For example, if items a and B are listed, the phrase "one of a and B" means a alone or B alone. In another example, if items A, B and C are listed, the phrase "one of A, B and C" means only a; only B; or only C. Item a may comprise a single element or multiple elements. Item B may comprise a single element or multiple elements. Item C may comprise a single element or multiple elements.

In the detailed description and claims, a list of items linked by the term "at least one of," "at least one of," or other similar terms may mean any combination of the listed items. For example, if items a and B are listed, the phrase "at least one of a and B" means a only; only B; or A and B. In another example, if items A, B and C are listed, the phrase "at least one of A, B and C" means a only; or only B; only C; a and B (excluding C); a and C (excluding B); b and C (excluding A); or A, B and C. Item a may comprise a single element or multiple elements. Item B may comprise a single element or multiple elements. Item C may comprise a single element or multiple elements.

First, negative electrode material

The embodiment of the application provides a negative electrode material, which comprises silicon-based particles and graphite particles, wherein the average sphericity of the graphite particles is A, the average sphericity of the silicon-based particles is B, and A and B satisfy the following conditions: about 0.1. ltoreq. B-A. ltoreq.0.3.

In some embodiments, B-a has a value of about 0.1, about 0.15, about 0.18, about 0.20, about 0.22, about 0.25, or about 0.28.

In some embodiments, the silicon-based particles have an average sphericity of about 0.8 to 1.0. In some embodiments, the silicon-based particles have an average sphericity of about 0.85, about 0.88, about 0.90, about 0.92, or about 0.95.

In some embodiments, the number of silicon-based particles having a sphericity of less than about 0.8 as a percentage of the total number of silicon-based particles is less than or equal to about 10%. In some embodiments, the number of silicon-based particles having a sphericity of less than about 0.8 as a percentage of the total number of silicon-based particles is less than or equal to about 9%, about 8%, about 7%, about 6%, about 5%, or about 4%.

In some embodiments, the graphite particles have an average sphericity of about 0.5 to 0.8. In some embodiments, the graphite particles have an average sphericity of about 0.53, about 0.55, about 0.58, about 0.60, about 0.62, about 0.65, or about 0.75.

In some embodiments, the percentage of the number of graphite particles having a sphericity of about 0.5 to 0.75 to the total number of graphite particles is greater than or equal to about 90%. In some embodiments, the percentage of the number of graphite particles having a sphericity of about 0.5 to 0.8 to the total number of graphite particles is greater than or equal to about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, or about 98%.

In some embodiments, the silicon-based particles have a maximum intensity value, I, in the range of about 28.0 ° to 29.5 ° for 2 θ in the X-ray diffraction pattern₂The highest intensity value assigned to the range of about 20.0-22.0 is I₁Wherein is about 0<I₂/I₁Less than or equal to about 1.

In some embodiments, the silicon-based particles have a 2 θ attributed to a maximum intensity value of I about 28.4 ° in the X-ray diffraction pattern₂The highest intensity value assigned to the range of about 21.0 is I₁Wherein is about 0<I₂/I₁Less than or equal to about 1. In some embodiments, I₂/I₁Is about 0.2, about 0.4, about 0.6, or about 0.8.

In some embodiments, D of the silicon-based particles _V50 is in the range of about 2.0 μm to 15 μm. In some embodiments, D of the silicon-based particles _V50 is in the range of about 4 μm to 10 μm. In some embodiments, D of the silicon-based particles _V50 is in the range of about 5 μm to 8 μm. In some embodiments, D of the silicon-based particles _V50 is in the range of about 3 μm, about 6 μm, about 7 μm, about 9 μm, about 12 μm, or about 14 μm.

In some embodiments, the silicon-based particles have a particle size distribution that satisfies: about 0.3. ltoreq. Dn10/Dv 50. ltoreq.about 0.6. In some embodiments, the silicon-based particles have a particle size distribution satisfying about 0.4. ltoreq. Dn10/Dv 50. ltoreq.0.5. In some embodiments, the silicon-based particles have a particle size distribution of about 0.35, about 0.45, or about 0.55.

In some embodiments, the silicon-based particles comprise a silicon composite matrix and an oxide MeO_yLayer of said oxide MeO_yA layer coating at least a portion of the silicon composite matrix, wherein Me comprises at least one of Al, Si, Ti, Mn, V, Cr, Co, or Zr, wherein y is 0.5 to 3;and wherein the oxide MeO_yThe layer comprises a carbon material.

In some embodiments, the oxide MeO_yIncluding Al₂O₃、TiO₂、ZrO、MnO、Mn₂O₃、Mn₃O₄、Co₃O₄、Cr₂O₃、SiO₂Or any combination thereof

In some embodiments, the oxide MeO_yThe carbon material in the layer comprises amorphous carbon, carbon nanotubes, carbon nanoparticles, carbon fibers, graphene, or any combination thereof. In some embodiments, the amorphous carbon is a carbon material obtained by sintering a carbon precursor at a high temperature. In some embodiments, the carbon precursor comprises polyvinylpyrrolidone, sodium carboxymethylcellulose, polyvinyl alcohol, polypropylene, acid phenolic resin, polyester resin, polyamide resin, epoxy resin, polyurethane, polyacrylic resin, or any combination thereof.

In some embodiments, the silicon-based particles further comprise a polymer layer coating at least a portion of the oxide MeOy layer, and the polymer layer comprises a carbon material. In some embodiments, the polymer layer may be coated directly on the surface of the silicon composite substrate. That is, the silicon-based particles comprise only a silicon composite matrix and a polymer layer.

In some embodiments, the polymer layer comprises polyvinylidene fluoride and derivatives thereof, carboxymethylcellulose and derivatives thereof, sodium carboxymethylcellulose and derivatives thereof, polyvinylpyrrolidone and derivatives thereof, polyacrylic acid and derivatives thereof, poly (styrene-butadiene rubber), polyacrylamide, polyimide, polyamideimide, or any combination thereof.

In some embodiments, the silicon composite matrix comprises particles capable of intercalating and deintercalating lithium ions. In some embodiments, the silicon composite matrix comprises a silicon-containing species, wherein the silicon-containing species in the silicon composite matrix and one or more of the other species in the anode material other than the silicon-containing species may form a composite.

In some casesIn an embodiment, the silicon composite substrate comprises SiO_xAnd x is greater than or equal to about 0.6 and less than or equal to about 1.5.

In some embodiments, the silicon composite matrix comprises nano-Si grains, SiO₂Or any combination thereof.

In some embodiments, the nano-Si grains are less than about 100nm in size. In some embodiments, the nano-Si grains are less than about 50nm in size. In some embodiments, the nano-Si grains are less than about 20nm in size. In some embodiments, the nano-Si grains are less than about 5nm in size. In some embodiments, the nano-Si grains are less than about 2nm in size.

In some embodiments, the oxide MeO_yThe thickness of the layer is about 0.5nm to 900 nm. In some embodiments, the oxide MeO_yThe thickness of the layer is about 1nm to 800 nm. In some embodiments, the oxide MeO_yThe thickness of the layer is about 1nm to 100 nm. In some embodiments, the oxide MeO_yThe thickness of the layer is about 1nm to 20 nm. In some embodiments, the oxide MeO_yThe thickness of the layer is about 2nm, about 10nm, about 20nm, about 50nm, about 60nm, about 70nm, about 80nm, about 90nm, or about 100 nm.

In some embodiments, the weight percentage of Me element is about 0.005 wt% to 1.5 wt% based on the total weight of the silicon-based particles. In some embodiments, the weight percentage of Me element is about 0.01 wt% to 1.2 wt% based on the total weight of the silicon-based particles. In some embodiments, the weight percentage of Me element is about 0.02 wt% to 1.0 wt% based on the total weight of the silicon-based particles. In some embodiments, the weight percentage of Me element is about 0.05 wt%, about 0.1 wt%, about 0.2 wt%, about 0.3 wt%, about 0.4 wt%, about 0.5 wt%, about 0.6 wt%, about 0.7 wt%, about 0.8 wt%, or about 0.9 wt%, based on the total weight of the silicon-based particles.

In some embodiments, the oxide MeO is based on the total weight of the silicon-based particles_yThe weight percent of carbon material in the layer is between about 0.01 wt% and 1.5 wt%. In some embodiments, the oxide is based on the total weight of the silicon-based particlesMeO_yThe weight percent of carbon material in the layer is between about 0.1 wt% and 1.0 wt%. In some embodiments, the oxide MeO is based on the total weight of the silicon-based particles_yThe weight percent of carbon material in the layer is between about 0.2 wt% and 0.9 wt%. In some embodiments, the oxide MeO is based on the total weight of the silicon-based particles_yThe weight percent of carbon material in the layer is about 0.3 wt%, about 0.4 wt%, about 0.5 wt%, about 0.6 wt%, about 0.7 wt%, or about 0.8 wt%.

In some embodiments, the carbon material in the polymer layer comprises carbon nanotubes, carbon nanoparticles, carbon fibers, graphene, or any combination thereof.

In some embodiments, the weight percent of the polymer layer is about 0.05 to 6 wt% based on the total weight of the silicon-based particles. In some embodiments, the weight percent of the polymer layer is about 0.1 to 5 wt% based on the total weight of the silicon-based particles. In some embodiments, the weight percent of the polymer layer is about 0.5 to 4 wt% based on the total weight of the silicon-based particles. In some embodiments, the weight percentage of the polymer layer is about 1 wt%, about 1.5 wt%, about 2 wt%, about 2.5 wt%, or about 3.0 wt%, based on the total weight of the silicon-based particles.

In some embodiments, the polymer layer has a thickness of about 1nm to 150 nm. In some embodiments, the polymer layer has a thickness of about 5nm to 120 nm. In some embodiments, the polymer layer has a thickness of about 10nm to 100 nm. In some embodiments, the polymer layer has a thickness of about 15nm, about 20nm, about 30nm, about 40nm, about 50nm, about 60nm, about 70nm, about 80nm, or about 90 nm.

In some embodiments, the anode material has a specific surface area of about 1-50m²(ii) in terms of/g. In some embodiments, the anode material has a specific surface area of about 5-40m²(ii) in terms of/g. In some embodiments, the anode material has a specific surface area of about 10-30m²(ii) in terms of/g. In some embodiments, the anode material has a specific surface area of about 1m²G, about 5m²In the range of/g or about 10m²/g。

In some embodiments, the stoneAbout 1330cm of ink particles in Raman spectroscopic analysis^-1Having a scattering peak I₁₃₃₀And at about 1580cm^-1Has a scattering peak I₁₅₈₀，I₁₃₃₀/I₁₅₈₀Satisfies a ratio of about 0.7 < I₁₃₃₀/I₁₅₈₀< about 2.0.

In some embodiments, I₁₃₃₀/I₁₅₈₀The ratio of (A) satisfies about 0.8 < I₁₃₃₀/I₁₅₈₀< about 1.8. In some embodiments, I₁₃₃₀/I₁₅₈₀Satisfies a ratio of about 1 < I₁₃₃₀/I₁₅₈₀< about 1.5.

In some embodiments, the graphite particles have a particle size Dv50 of about 0.01-90 μm. In some embodiments, the graphite particles have a particle size Dv50 of about 1-80 μm. In some embodiments, the graphite particles have a particle size Dv50 of about 5-70 μm. In some embodiments, the graphite particles have a particle size Dv50 of about 10-60 μm. In some embodiments, the graphite particles have a particle size Dv50 of about 15 μm, about 20 μm, about 25 μm, about 30 μm, about 35 μm, about 40 μm, or about 45 μm.

In some embodiments, the graphite particles have a specific surface area of less than or equal to about 30m²(ii) in terms of/g. In some embodiments, the graphite particles have a specific surface area of less than or equal to about 25m²(ii) in terms of/g. In some embodiments, the graphite particles have a specific surface area of less than or equal to about 20m²(ii) in terms of/g. In some embodiments, the graphite particles have a specific surface area of less than or equal to about 15m²/g。

In some embodiments, the graphite particles have an X-ray diffraction pattern comprising a 004 diffraction pattern and a 110 diffraction pattern, wherein C004 for a unit cell length is obtained from the 004 diffraction pattern, C110 for a unit cell length is obtained from the 110 diffraction pattern, the ratio of C004/C110 is an Orientation Index (OI) of the graphite particles, and the OI value of the graphite particles is about 1-30.

In some embodiments, the graphite particles have an OI value of about 1 to 20. In some embodiments, the graphite particles have an OI value of about 5, about 10, or about 15.

In some embodiments, about 0 is satisfied<I₂/I₁A method of making silicon-based particles of up to about 1 comprises:

(1) mixing silicon dioxide and metal silicon powder in a molar ratio of about 1:5-5:1 to obtain a mixed material;

(2) at about 10^-4-10^-1Heating the mixed material at a temperature of about 1100-;

(3) condensing the gas obtained to obtain a solid;

(4) pulverizing and sieving the solid to obtain the silicon-based particles; and

(5) heat treating the solid in the range of about 400 ℃ and 1500 ℃ for about 1-20h, and cooling the heat treated solid to obtain the silicon-based particles.

In some embodiments, the silica to metal silicon powder molar ratio is about 1:4 to 4: 1. In some embodiments, the silica to metal silicon powder molar ratio is about 1:3 to 3: 1. In some embodiments, the silica to metal silicon powder molar ratio is about 1:2 to 2: 1. In some embodiments, the silica to metal silicon powder molar ratio is about 1: 1.

In some embodiments, the pressure range is about 10^-4-10^-1kPa. In some embodiments, the pressure is about 1Pa, about 10Pa, about 20Pa, about 30Pa, about 40Pa, about 50Pa, about 60Pa, about 70Pa, about 80Pa, about 90Pa, or about 100 Pa.

In some embodiments, the heating temperature is about 1100-. In some embodiments, the heating temperature is about 1200 ℃, about 1250 ℃, about 1300 ℃, or about 1400 ℃.

In some embodiments, the heating time is about 1-20 hours. In some embodiments, the heating time is about 5-16 h. In some embodiments, the heating time is about 2h, about 4h, about 6h, about 8h, about 10h, about 12h, about 14h, about 15h, or about 18 h.

In some embodiments, the mixing is performed by a ball mill, a V-blender, a three-dimensional blender, an air blender, or a horizontal blender.

In some embodiments, the heating is performed under an inert gas blanket. In some embodiments, the inert gas comprises nitrogen, argon, helium, or a combination thereof.

In some embodiments, the temperature of the heat treatment is about 400-1200 ℃. In some embodiments, the temperature of the heat treatment is about 500 ℃, about 600 ℃, about 700 ℃, about 800 ℃, about 900 ℃, or about 1000 ℃.

In some embodiments, the heat treatment time is about 1-18 hours. In some embodiments, the heat treatment time is about 2-12 hours. In some embodiments, the time of the heat treatment is about 3 hours, about 5 hours, about 8 hours, about 10 hours, about 12 hours, or about 15 hours.

In some embodiments, the surface has an oxide MeO_yThe preparation method of the coated silicon-based particles comprises the following steps:

(1) the solid or commercial silicon oxide SiO obtained after the classification_xCarbon precursor and oxide precursor MeT_nForming a mixed solution in the presence of an organic solvent and deionized water;

(2) drying the mixed solution to obtain powder; and

(3) sintering the powder at about 250 ℃ and 1000 ℃ for about 0.5-20h to obtain the powder with the oxide MeO on the surface_ySilicon-based particles of the layer;

wherein x is from about 0.5 to 1.5;

y is in the range of about 0.5 to 3,

wherein Me comprises at least one of Al, Si, Ti, Mn, Cr, V, Co or Zr,

wherein T comprises at least one of methoxy, ethoxy, isopropoxy, or halogen, and

wherein n is 1, 2, 3 or 4.

In some embodiments, the oxide precursor MeT_nIncluding isopropyl titanate, aluminum isopropoxide, or combinations thereof.

In some embodiments, the carbon material comprises amorphous carbon, carbon nanotubes, carbon nanoparticles, carbon fibers, graphene, or any combination thereof. In some embodiments, the amorphous carbon is a carbon material obtained by sintering a carbon precursor at a high temperature. In some embodiments, the carbon precursor comprises polyvinylpyrrolidone, sodium carboxymethylcellulose, polyvinyl alcohol, polypropylene, acid phenolic resin, polyester resin, polyamide resin, epoxy resin, polyurethane, polyacrylic resin, or any combination thereof.

In some embodiments, the sintering temperature is about 300-. In some embodiments, the sintering temperature is about 350-. In some embodiments, the sintering temperature is about 400-650 ℃. In some embodiments, the sintering temperature is about 450 ℃, about 500 ℃, about 600 ℃, about 750 ℃, or about 800 ℃.

In some embodiments, the sintering time is about 1-20 hours. In some embodiments, the sintering time is about 1-15 hours. In some embodiments, the sintering time is about 1-10 hours. In some embodiments, the sintering time is about 1-5 hours. In some embodiments, the sintering time is about 2 hours, about 3 hours, about 4 hours, about 6 hours, about 8 hours, or about 12 hours.

In some embodiments, the organic solvent comprises at least one of: ethanol, methanol, N-hexane, N-dimethylformamide, pyrrolidone, acetone, toluene, isopropanol or N-propanol. In some embodiments, the organic solvent is ethanol.

In some embodiments, the halogen comprises F, Cl, Br, or a combination thereof.

In some embodiments, the sintering is performed under an inert gas blanket. In some embodiments, the inert gas comprises nitrogen, argon, or a combination thereof.

In some embodiments, the drying is spray drying, with a drying temperature of about 100-.

In some embodiments, a method of making a silicon-based particle having a polymer coating on a surface thereof comprises:

(1) the solid, commercial silica compound SiO obtained after crushing and sieving_xOr having oxide MeO on the surface_yDispersing the silicon-based particles, the carbon material and the polymer in the solvent at a high speed for 1-15h to obtain a suspension; and

(2) the solvent in the suspension is removed and,

wherein x is from about 0.5 to about 1.5.

In some embodiments, the dispersion time is about 2 hours, about 3 hours, about 4 hours, about 5 hours, about 6 hours, about 7 hours, about 8 hours, or about 10 hours.

In some embodiments, the polymer comprises polyvinylidene fluoride and derivatives thereof, carboxymethylcellulose and derivatives thereof, sodium carboxymethylcellulose and derivatives thereof, polyvinylpyrrolidone and derivatives thereof, polyacrylic acid and derivatives thereof, poly (styrene-butadiene rubber), polyacrylamide, polyimide, polyamideimide, or any combination thereof.

In some embodiments, the carbon material comprises carbon nanotubes, carbon nanoparticles, carbon fibers, graphene, or any combination thereof.

In some embodiments, the solvent comprises water, ethanol, methanol, tetrahydrofuran, acetone, chloroform, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, toluene, xylene, or any combination thereof.

Fig. 1A shows an SEM picture of silicon oxide SiOx in example 1; fig. 1B shows an SEM picture of the graphite particles in example 1; and fig. 1C shows an SEM picture of a portion of the negative electrode in example 1. Fig. 2A shows a particle size distribution curve of silicon oxide SiOx in example 1; and fig. 2B shows a particle size distribution curve of graphite in example 1.

Industry commonly mixes silica materials with graphite materials in certain proportions to produce negative electrodes. The prior art generally only focuses on improvements to the silica material to improve the performance of the negative electrode, and neglects the effect of reasonable matching between the silica material particles and the graphite particles on the performance of the negative electrode. The silica material particles and graphite particles do not expand in volume in the lithium intercalation process. The application finds that the silicon-oxygen material particles in the negative electrode can be matched with the graphite particles reasonably to uniformly disperse the overall expansion stress of the negative electrode, so that the silicon-oxygen material particles are filled in gaps among the graphite and are embedded together like gears, and the compaction density of the negative electrode is increased. And can inhibit the displacement of particles caused by expansion, reduce the deformation of the negative electrode and prolong the cycle life of the battery. Therefore, the reasonable matching of the silica material particles and the graphite particles has important significance for improving the performance of the battery.

Fig. 3A is a cycle decay curve for the lithium ion batteries in example 1 and comparative example 1; fig. 3B is a deformation curve of the lithium ion batteries in example 1 and comparative example 1.

As can be seen from fig. 3A, the capacity retention of example 1 is higher than that of comparative example 1. As can be seen from fig. 3B, the deformation ratio of the battery in example 1 was smaller than that of the battery in comparative example 1.

Fig. 3C shows an X-ray diffraction (XRD) pattern of the negative active material of example 10 of the present application. As can be seen from FIG. 3C, the anode active material has a maximum intensity value I in the range of about 28.0-29.0 in terms of 2 θ in the X-ray diffraction pattern₂The highest intensity value is assigned to I in the range of about 20.5 DEG to 21.5 DEG₁Wherein is about 0<I₂/I₁Less than or equal to about 1. I is₂/I₁The magnitude of the value reflects the degree of influence of material disproportionation. I is₂/I₁The larger the value, the larger the size of the nano silicon crystal grains inside the negative electrode active material. When I is₂/I₁At values greater than about 1, the negative active material can cause a sharp increase in localized stress during intercalation, resulting in structural degradation of the negative active material during cycling. In addition, the ability of the grain boundaries to diffuse during ion diffusion can be affected by the creation of nanocrystalline distributions. The inventor of the present application finds that when I₂/I₁The value satisfies about 0<I₂/I₁When the content is less than or equal to about 1, the negative electrode active material has good cycle performance, and the lithium ion battery prepared from the negative electrode active material has good expansion resistance.

Fig. 3D shows an X-ray diffraction (XRD) pattern of the negative active material of comparative example 4 of the present application. As can be seen from FIG. 3D, I of the negative active material of comparative example 4₂/I₁Significantly greater than 1. The negative active material of comparative example 4 had inferior cycle performance, and the lithium ion battery prepared therefrom had high expansion rate and inferior rate performance, compared to the negative active material of example 1.

FIG. 4 shows a negative of one embodiment of the present applicationSchematic of the structure of the pole active material. Wherein the inner layer 1 is a silicon composite matrix and the outer layer 2 is an oxide MeO comprising a carbon material_yAnd (3) a layer.

Oxide MeO coating the silicon composite matrix_yThe oxide can react with HF in the electrolyte to reduce the content of HF in the electrolyte in the circulating process and reduce the etching of HF on the surface of the silicon material, so that the circulating performance of the material is further improved. Oxide MeO_yThe layer is doped with a certain amount of carbon to enhance the conductivity of the negative active material and reduce polarization during cycling.

Fig. 5 shows a schematic view of the structure of a negative active material according to another embodiment of the present application. Wherein the inner layer 1 is a silicon composite matrix and the intermediate layer 2 is an oxide MeO comprising a carbon material_yThe outer layer 3 is a polymer layer containing a carbon material. The negative active material of the present application may also have only a silicon composite matrix and a polymer layer without MeO_yAnd (3) a layer. That is, the polymer layer of the present application may be coated directly on the surface of the silicon composite substrate.

The polymer layer containing the Carbon Nano Tube (CNT) is coated on the surface of the negative active material, and the CNT can be bound on the surface of the negative active material by using the polymer, so that the interface stability of the surface of the negative active material is improved, and the silicon-based particle deviation is bound, thereby improving the cycle performance and improving the deformation.

Second, negative pole

In some embodiments, the negative electrode includes a current collector and a negative active material layer on the current collector. The negative active material layer includes a negative electrode material according to an embodiment of the present application.

In some embodiments, the negative active material layer includes a binder. In some embodiments, the adhesive includes, but is not limited to: polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene 1, 1-difluoroethylene, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, or nylon.

In some embodiments, the negative active material layer includes a conductive material. In some embodiments, the conductive material includes, but is not limited to: natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, metal powder, metal fiber, copper, nickel, aluminum, silver, or polyphenylene derivative.

In some embodiments, the current collector includes, but is not limited to: copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, or a polymer substrate coated with a conductive metal.

In some embodiments, the negative electrode may be obtained by: the active material, the conductive material, and the binder are mixed in a solvent to prepare an active material composition, and the active material composition is coated on a current collector.

In some embodiments, the solvent may include, but is not limited to: n-methyl pyrrolidone.

III, positive electrode

Materials, compositions, and methods of making positive electrodes useful in embodiments of the present application include any of the techniques disclosed in the prior art. In some embodiments, the positive electrode is the positive electrode described in U.S. patent application No. US9812739B, which is incorporated by reference herein in its entirety.

In some embodiments, the positive electrode includes a current collector and a positive active material layer on the current collector.

In some embodiments, the positive active material includes, but is not limited to: lithium cobaltate (LiCoO2), lithium Nickel Cobalt Manganese (NCM) ternary materials, lithium iron phosphate (LiFePO4) or lithium manganate (LiMn2O 4).

In some embodiments, the positive active material layer further includes a binder, and optionally a conductive material. The binder improves the binding of the positive electrode active material particles to each other, and also improves the binding of the positive electrode active material to the current collector.

In some embodiments, the adhesive includes, but is not limited to: polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene 1, 1-difluoroethylene, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, or the like.

In some embodiments, the conductive material includes, but is not limited to: carbon-based materials, metal-based materials, conductive polymers, and mixtures thereof. In some embodiments, the carbon-based material is selected from natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, or any combination thereof. In some embodiments, the metal-based material is selected from metal powder, metal fiber, copper, nickel, aluminum, or silver. In some embodiments, the conductive polymer is a polyphenylene derivative.

In some embodiments, the current collector may include, but is not limited to: aluminum.

The positive electrode may be prepared by a preparation method well known in the art. For example, the positive electrode can be obtained by: the active material, the conductive material, and the binder are mixed in a solvent to prepare an active material composition, and the active material composition is coated on a current collector. In some embodiments, the solvent may include, but is not limited to: n-methyl pyrrolidone.

IV, electrolyte

The electrolyte that may be used in the embodiments of the present application may be an electrolyte known in the art.

In some embodiments, the electrolyte includes an organic solvent, a lithium salt, and an additive. The organic solvent of the electrolyte according to the present application may be any organic solvent known in the art that can be used as a solvent of the electrolyte. The electrolyte used in the electrolyte according to the present application is not limited, and may be any electrolyte known in the art. The additive of the electrolyte according to the present application may be any additive known in the art as an additive of electrolytes.

In some embodiments, the organic solvent includes, but is not limited to: ethylene Carbonate (EC), Propylene Carbonate (PC), diethyl carbonate (DEC), Ethyl Methyl Carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate or ethyl propionate.

In some embodiments, the lithium salt comprises at least one of an organic lithium salt or an inorganic lithium salt.

In some embodiments, the lithium salt includes, but is not limited to: lithium hexafluorophosphate (LiPF)₆) Lithium tetrafluoroborate (LiBF)₄) Lithium difluorophosphate (LiPO)₂F₂) Lithium bis (trifluoromethanesulfonylimide) LiN (CF)₃SO₂)₂(LiTFSI), lithium bis (fluorosulfonyl) imide Li (N (SO)₂F)₂) (LiFSI), lithium bis (oxalato) borate LiB (C)₂O₄)₂(LiBOB) or lithium difluorooxalato borate LiBF₂(C₂O₄)(LiDFOB)。

In some embodiments, the concentration of lithium salt in the electrolyte is: about 0.5 to 3mol/L, about 0.5 to 2mol/L, or about 0.8 to 1.5 mol/L.

Five, isolating film

In some embodiments, a separator is provided between the positive and negative electrodes to prevent short circuits. The material and shape of the separation film that can be used for the embodiment of the present application are not particularly limited, and may be any of the techniques disclosed in the prior art. In some embodiments, the separator includes a polymer or inorganic substance or the like formed of a material stable to the electrolyte of the present application.

For example, the release film may include a substrate layer and a surface treatment layer. The substrate layer is a non-woven fabric, a film or a composite film with a porous structure, and the material of the substrate layer is at least one selected from polyethylene, polypropylene, polyethylene terephthalate and polyimide. Specifically, a polypropylene porous film, a polyethylene porous film, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric, or a polypropylene-polyethylene-polypropylene porous composite film can be used.

At least one surface of the substrate layer is provided with a surface treatment layer, and the surface treatment layer can be a polymer layer or an inorganic layer, or a layer formed by mixing a polymer and an inorganic substance.

The inorganic layer comprises inorganic particles and a binder, wherein the inorganic particles are selected from one or more of aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium oxide, tin oxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide and barium sulfate. The binder is selected from one or a combination of more of polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene and polyhexafluoropropylene.

The polymer layer comprises a polymer, and the material of the polymer is selected from at least one of polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride or poly (vinylidene fluoride-hexafluoropropylene).

Sixth, electrochemical device

Embodiments of the present application provide an electrochemical device including any device in which an electrochemical reaction occurs.

In some embodiments, the electrochemical device of the present application includes a positive electrode having a positive electrode active material capable of occluding and releasing metal ions; a negative electrode according to an embodiment of the present application; an electrolyte; and a separator interposed between the positive electrode and the negative electrode.

In some embodiments, the electrochemical devices of the present application include, but are not limited to: all kinds of primary batteries, secondary batteries, fuel cells, solar cells or capacitors.

In some embodiments, the electrochemical device is a lithium secondary battery.

In some embodiments, the lithium secondary battery includes, but is not limited to: a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery.

Seventh, electronic device

The electronic device of the present application may be any device using the electrochemical device according to the embodiment of the present application.

In some embodiments, the electronic devices include, but are not limited to: a notebook computer, a pen-input computer, a mobile computer, an electronic book player, a cellular phone, a portable facsimile machine, a portable copier, a portable printer, a headphone, a video recorder, a liquid crystal television, a portable cleaner, a portable CD player, a mini-disc, a transceiver, an electronic organizer, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, an automobile, a motorcycle, a power-assisted bicycle, a lighting apparatus, a toy, a game machine, a clock, an electric tool, a flashlight, a camera, a large-sized household battery or a lithium ion capacitor, and the like.

Taking a lithium ion battery as an example and describing the preparation of the lithium ion battery with reference to specific examples, those skilled in the art will understand that the preparation method described in the present application is only an example, and any other suitable preparation method is within the scope of the present application.

Examples

The following describes performance evaluation according to examples and comparative examples of lithium ion batteries of the present application.

Method for evaluating performance of negative electrode active material

1. Method for testing powder property of negative electrode active material

(1) And (3) observing the micro-morphology of the powder particles: observing the microscopic morphology of the powder by using a scanning electron microscope to represent the surface coating condition of the material, wherein the selected test instruments are as follows: OxFORD EDS (X-max-20 mm)²) And the accelerating voltage is 15KV, the focal length is adjusted, the observation multiple is observed at high power from 50K, and the particle agglomeration condition is mainly observed at low power of 500-2000.

(2) And (3) testing the sphericity: utilizing a Malvern automatic image particle size analyzer to capture and process a certain number (more than 5000) of dispersed particles, then accurately analyzing the microstructure and the morphology of the particles by an image-guided Raman spectroscopy (MDRS) technology to obtain the longest diameter and the shortest diameter of all the particles, calculating the ratio of the shortest diameter and the longest diameter of each particle to obtain the sphericity of each particle, and averaging the sphericity of all the particles to obtain the average sphericity;

(3) specific surface area test: after the adsorption amount of the gas on the solid surface at different relative pressures is measured at constant temperature and low temperature, the adsorption amount of the monolayer of the sample is obtained based on the Bronuore-Eltt-Taylor adsorption theory and the formula (BET formula) thereof, and the specific surface area of the solid is calculated.

About 1.5-3.5g of the powder sample was weighed into a test sample tube of TriStar II 3020, degassed at about 200 ℃ for 120min and tested.

(4) And (3) testing the granularity: about 0.02g of the powder sample was added to a 50ml clean beaker, about 20ml of deionized water was added, a few drops of 1% surfactant were added dropwise to completely disperse the powder in water, sonicated in a 120W ultrasonic cleaner for 5 minutes, and the particle size distribution was measured using a MasterSizer 2000.

(5) And (3) testing the carbon content: the sample is heated and combusted at high temperature by a high-frequency furnace under the condition of oxygen enrichment to respectively oxidize carbon and sulfur into carbon dioxide and sulfur dioxide, the gas enters a corresponding absorption cell after being treated, corresponding infrared radiation is absorbed, and then the infrared radiation is converted into corresponding signals by a detector. The signal is sampled by a computer, is converted into a numerical value in direct proportion to the concentration of carbon dioxide and sulfur dioxide after linear correction, then the value of the whole analysis process is accumulated, after the analysis is finished, the accumulated value is divided by a weight value in the computer, and then multiplied by a correction coefficient, and blank is deducted, thus the percentage content of carbon and sulfur in the sample can be obtained. The sample was tested using a high frequency infrared carbon sulfur analyzer (Shanghai DE Ky HCS-140).

(6) XRD test: weighing 1.0-2.0g of sample, pouring the sample into a groove of a glass sample rack, compacting and grinding the sample by using a glass sheet, testing by using an X-ray diffractometer (Bruk, D8) according to JJS K0131-₂And the highest intensity I attributed to 21.0 DEG₁Thereby calculating I₂/I₁The ratio of (a) to (b).

(7) And (3) testing metal elements: weighing a certain amount of sample, adding a certain amount of concentrated nitric acid into the sample, performing microwave digestion to obtain a solution, washing the obtained solution and filter residue for multiple times, fixing the volume to a certain volume, testing the plasma intensity of metal elements in the solution through ICP-OES, and calculating the metal content in the solution according to a standard curve of the measured metal, thereby calculating the amount of the metal elements contained in the material.

(8) And (3) testing the porosity of the negative electrode: the negative electrode was punched into small 13mm disks with a punch, and the thickness of the disks was measured using a ten-thousandth ruler. Placing a certain number of small wafers into a sample cabin of an AccuPyc 1340 instrument, purging a sample for 30 times by using helium gas, introducing the helium gas according to a program, and calculating the true volume in the sample cabin by testing the pressure in the sample cabin and utilizing the Bohr's law PV-nRT. And counting the number of the small discs after the test is finished, and calculating the apparent volume of the sample. 1-true volume/apparent volume, giving the porosity of the sample.

The weight percentages of each material in the following tables are calculated based on the total weight of the anode active material.

Second, electrical property test method of negative electrode active material

1. The button cell testing method comprises the following steps:

under dry argon atmosphere, LiPF is added into a solvent formed by mixing Propylene Carbonate (PC), Ethylene Carbonate (EC) and diethyl carbonate (DEC) (the weight ratio is about 1: 1: 1)₆Mixing uniformly, wherein LiPF₆Was added with about 7.5 wt% of fluoroethylene carbonate (FEC), and mixed uniformly to obtain an electrolyte solution.

The negative electrode active materials, conductive carbon black, and a binder PAA (modified polyacrylic acid, PAA) obtained in examples and comparative examples were mixed in a weight ratio of about 80: 10: 10 adding the mixture into deionized water, stirring to form slurry, coating by using a scraper to form a coating with the thickness of about 100 mu m, drying at about 85 ℃ for about 12 hours in a vacuum drying oven, cutting into round pieces with the diameter of about 1cm by using a punch in a drying environment, taking a metal lithium piece as a counter electrode in a glove box, selecting a ceglard composite film as an isolating film, and adding electrolyte to assemble the button cell. The battery was subjected to a charge-discharge test using a blue electricity (LAND) series battery test, and its charge-discharge capacity was tested.

Firstly, discharging to 0.005V by adopting 0.05C, discharging to 0.005V by using 50 muA after standing for 5 minutes, and discharging to 0.005V by using 10 muA after standing for 5 minutes to obtain the first lithium intercalation capacity of the material; then charged to 2V with 0.1C to obtain the first delithiation capacity. Finally, the first lithium insertion capacity is the first efficiency of the material according to the first lithium removal capacity ratio.

2. Full battery test

(1) Preparation of lithium ion battery

Preparation of the Positive electrode

Subjecting LiCoO to condensation₂The conductive carbon black and polyvinylidene fluoride (PVDF) are fully stirred and uniformly mixed in an N-methyl pyrrolidone solvent system according to the weight ratio of about 95 percent to 2.5 percent to prepare the anode slurry. And coating the prepared anode slurry on an anode current collector aluminum foil, drying and cold pressing to obtain the anode.

Preparation of the negative electrode

Graphite, the silicon-based negative active materials prepared according to examples and comparative examples, a conductive agent (conductive carbon black,

) And binder PAA in a weight ratio of about 95%: 1.2%: 5%: 3.8%, an appropriate amount of water was added and kneaded at a solid content of about 30 wt% to 60 wt%. Adding a proper amount of water, and adjusting the viscosity of the slurry to about 2000-3000 Pa.s to prepare the cathode slurry.

And coating the prepared negative electrode slurry on a negative electrode current collector copper foil, drying and cold pressing to obtain a negative electrode.

Preparation of the electrolyte

Under dry argon atmosphere, LiPF is added into a solvent formed by mixing Propylene Carbonate (PC), Ethylene Carbonate (EC) and diethyl carbonate (DEC) (the weight ratio is about 1: 1: 1)₆Mixing uniformly, wherein LiPF₆Is about 1.15mol/L, and then addingAbout 7.5 wt% fluoroethylene carbonate (FEC) was then mixed uniformly to obtain an electrolyte.

Preparation of the separator

The PE porous polymer film is used as a separation film.

Preparation of lithium ion battery

The anode, the isolating film and the cathode are sequentially stacked, and the isolating film is positioned between the anode and the cathode to play a role in isolation. And winding to obtain the naked electric core. And arranging the bare cell in an external package, injecting electrolyte and packaging. The lithium ion battery is obtained through the technological processes of formation, degassing, edge cutting and the like.

(2) And (3) testing the cycle performance:

the test temperature was 25/45 ℃, and the test temperature was constant current charged to 4.4V at 0.7C, constant voltage charged to 0.025C, and discharged to 3.0V at 0.5C after standing for 5 minutes. And taking the capacity obtained in the step as the initial capacity, carrying out a cyclic test of 0.7C charging/0.5C discharging, and taking the ratio of the capacity of each step to the initial capacity to obtain a capacity fading curve. The cycle number of the battery with the capacity retention rate of 90% after the cycle at 25 ℃ is recorded as the room-temperature cycle performance of the battery, the cycle number of the battery with the capacity retention rate of 80% after the cycle at 45 ℃ is recorded as the high-temperature cycle performance of the battery, and the cycle performance of the materials is compared by comparing the cycle number of the two cases.

(3) And (3) testing discharge rate:

discharging to 3.0V at 0.2C at 25 ℃, standing for 5min, charging to 4.45V at 0.5C, charging to 0.05C at constant voltage, standing for 5min, adjusting discharge rate, performing discharge tests at 0.2C, 0.5C, 1C, 1.5C and 2.0C respectively to obtain discharge capacity, comparing the capacity obtained at each rate with the capacity obtained at 0.2C, and comparing rate performance by comparing the ratio of 2C to 0.2C.

(4) And (3) testing the full-charge deformation rate of the battery:

and (3) testing the thickness of the fresh battery in the half-charging (50% charging State (SOC)) by using a spiral micrometer, circulating to 400 circles, and testing the thickness of the battery at the moment by using the spiral micrometer when the battery is in the full-charging (100% SOC) state, and comparing the thickness of the battery with the thickness of the fresh battery in the initial half-charging (50% SOC) state to obtain the deformation rate of the full-charging (100% SOC) battery at the moment.

Thirdly, composition and performance test results of the negative electrode

1. Selection of commercial silicon oxide SiO_x(0.5<x<1.5，D _V50 ═ about 5.3 μm) and graphite particles (D)_V50 ═ about 14.0 μm) negative electrodes of examples 1 to 3 and comparative example 1 were prepared in accordance with the above-described method.

Table 1-1 shows the compositions of the anodes in examples 1-5 and comparative example 1.

TABLE 1-1

Gram capacity here is the capacity obtained by delithiation to a voltage of 2.0V (same below).

Tables 1 to 2 show the results of performance tests of the lithium ion batteries in the negative electrodes of examples 1 to 5 and comparative example 1.

Tables 1 to 2

As can be seen from the test results of examples 1 to 5 and comparative example 1, when the difference in average sphericity between the silicon-based particles and the graphite particles is in the range of less than or equal to about 0.3, the cycle performance, the deformation resistance, and the rate capability of the lithium ion battery prepared therefrom are significantly superior to those of the lithium ion battery having an average sphericity difference of more than 0.3.

This is because when the difference between the average sphericities of the silicon-based particles and the graphite particles is in the range of 0.3 or less, the difference between the morphologies can be effectively utilized, the maximum compacted density of the negative electrode material is increased, and the energy density of the battery cell is increased. In addition, rearrangement in the expansion and contraction process of the particles is inhibited, pores among the particles are reduced, electric contact between the graphite particles and the silicon-based particles is enhanced, and the cycle performance and the deformation resistance of the battery core are improved.

2. Negative electrodes of examples 6 to 8 and comparative example 2 were prepared as follows:

(1) respectively carrying out mechanical dry mixing and ball milling mixing on silicon dioxide and metal silicon powder in a molar ratio of about 1:1 to obtain a mixed material;

(2) at Ar₂Under an atmosphere of about 10 deg.C^-3-10^-1Heating the mixed material at a temperature of about 1100-;

(3) condensing the gas obtained to obtain a solid;

(4) crushing and screening the solid;

(5) heat treating the solid at about 400-1500 ℃ for about 1-20h, cooling the heat treated solid to obtain the silica material SiO_xAs a silicon-based negative active material; and

(6) the negative electrodes of examples 6 to 8 and comparative example 2 were prepared in the above-described manner, and the average sphericities of the silicon-based particles and the graphite particles were about 0.92 and about 0.68, respectively.

Table 2-1 shows specific process parameters in steps (1) - (5).

TABLE 2-1

Tables 2 to 2 show performance parameters of the silicon-based negative active materials and graphite particles in examples 6 to 8 and comparative example 2.

Tables 2 to 2

Tables 2 to 3 show the results of the performance tests of the lithium ion batteries in examples 6 to 8 and comparative example 2.

Tables 2 to 3

As can be seen from the results of the performance tests of examples 6 to 8 and comparative example 2, the same applies toAnd B-A is less than or equal to about 0.3, about 0 is selected<I₂/I₁Silicon oxide SiO ≦ about 1_xThe prepared lithium ion battery has the cycle performance, the anti-deformation performance and the rate capability superior to about 1<I₂/I₁The lithium ion battery prepared from the silicon oxide.

3. Negative electrodes of examples 9 to 11 and comparative examples 3 and 4 were prepared as follows:

(1) by mixing commercial silicon oxide SiO_xScreening and classification treatments were performed to obtain silicon-based negative active materials of examples 9 to 11 and comparative examples 3 and 4;

(2) the negative electrodes of examples 9 to 11 and comparative examples 3 and 4 were prepared in the above-described manner, and the average sphericities of the silicon-based particles and the graphite particles, which were the same as those of the graphite particles in table 2-2, were about 0.92 and about 0.68, respectively.

Table 3-1 shows performance parameters of the silicon-based anode active materials in examples 9-11 and comparative examples 3 and 4.

TABLE 3-1

Table 3-2 shows the performance test results of the lithium ion batteries prepared from the negative electrodes of examples 9-11 and comparative examples 3 and 4.

TABLE 3-2

From the performance test results of examples 9-11 and comparative examples 3 and 4, it can be seen that the cycling performance, deformation resistance and rate capability of lithium ion batteries prepared with silicon oxides satisfying about 0.3. ltoreq. Dn10/Dv 50. ltoreq.0.6 are better than those prepared with silicon oxides Dn10/Dv50< about 0.3 or about 0.6< Dn10/Dv50 with the same satisfaction of B-A of less than or equal to about 0.3.

4. The anodes of examples 12-15 were prepared by the following method:

(1) commercial silicon oxide SiO_x(0.5<x<1.5，D_VAbout 5 μm) 50), a carbon precursor and an oxide precursor wet_nAdding to about 150mL of ethanol and about 1.47mL of deionized water, and stirring for about 4 hours until a homogeneous suspension is formed;

(2) spray drying (inlet temperature about 220 ℃, outlet temperature about 110 ℃) the suspension to obtain a powder;

(3) sintering the powder at about 250 ℃ and 1000 ℃ for about 0.5-20h to obtain the powder with the oxide MeO on the surface_yThe silicon oxide of the layer is used as a silicon-based negative electrode active material; and

(4) the negative electrodes of examples 12-15 were prepared according to the above-described method, and the average sphericities of the silicon-based particles and the graphite particles, which were the same as those of the graphite particles in table 2-2, were about 0.92 and about 0.68, respectively.

The MeO having the oxide in production examples 12 to 15 is shown in Table 4-1_ySilicon oxide SiO of coating layer_xThe process conditions of (1).

TABLE 4-1

Wherein "-" means that the substance was not added.

Table 4-2 shows the composition and performance parameters of the silicon-based anode active materials in example 1 and examples 12-15.

TABLE 4-2

Wherein "-" means that the substance was not added.

Tables 4 to 3 show the performance test results of the lithium ion batteries prepared from the negative electrodes in example 1 and examples 12 to 15.

Tables 4 to 3

From the test results of example 1 and examples 12 to 15, it can be seen that the silicon oxide is coated with the oxide MeO while also satisfying that B-A is less than or equal to about 0.3_yThe layer may further improve the cycling and/or rate capability and the deformation resistance of the lithium ion battery.

5. The negative electrodes of examples 16-21 were prepared by the following method:

(1) dispersing a carbon material (single-walled carbon nanotubes (SCNT) and/or multi-walled carbon nanotubes (MCNT)) and a polymer in water at a high speed for about 12 hours to obtain a uniformly mixed slurry;

(2) commercial silicon oxide SiOx (0.5)<x<1.5，D _V50 to about 5 μm) was added to the slurry uniformly mixed in (1) and stirred for about 4 hours to obtain a uniformly mixed dispersion;

(3) spray-drying (inlet temperature about 200 ℃ C., outlet temperature about 110 ℃ C.) the dispersion to obtain a powder as a silicon-based negative active material; and

(4) the negative electrodes of examples 16-21 were prepared as described above, and the average sphericities of the silicon-based particles and the graphite particles, which were the same as those of the graphite particles in table 2-2, were about 0.92 and about 0.68, respectively.

Table 5-1 shows the composition of the silicon oxide SiOx with polymer clad layers of examples 16-21.

TABLE 5-1

Wherein "-" means that the substance was not added.

The English abbreviations in Table 5-1 are all as follows:

SCNT: single-walled carbon nanotubes

MCNT: multiwalled carbon nanotube

CMC-Na: sodium carboxymethylcellulose

PVP: polyvinylpyrrolidone

PVDF: polyvinylidene fluoride

PAANa: polyacrylamide sodium salt

Tables 5-2 show the performance test results of the lithium ion batteries prepared from the negative electrodes of example 1 and examples 16-21.

TABLE 5-2

As can be seen from the test results of example 1 and examples 16-21, coating the silicon oxide with the carbon nanotube-containing polymer layer can further improve the cycle performance and/or rate capability and deformation resistance of the lithium ion battery, also satisfying that B-a is less than about 0.3.

6. Negative active materials of examples 22 to 24 and comparative examples 5 and 6 were prepared:

(1) preparation I₂/I₁A silicon-based negative active material having a value of about 0.5, which was prepared in a similar manner to that of example 7 except that the temperature of the post-classification heat treatment was 500 ℃ for 2 hours;

(2) further classification treatment was carried out to obtain silicon-based negative active materials of examples 22 to 24 and comparative examples 5 and 6; and

(3) negative electrodes of examples 22 to 24 and comparative examples 5 and 6, in which SiO was prepared according to the above-described method_xThe silicon-based particles having a number of graphite particles of 8 to 14 around the particles, which are the same as the graphite particles in tables 2 to 2, account for about 70% of the total number of the silicon-based particles, and the average sphericities of the silicon-based particles and the graphite particles are about 0.92 and about 0.68, respectively.

Table 6-1 shows performance parameters of the silicon-based anode active materials of examples 22-24 and comparative examples 5 and 6.

TABLE 6-1

Table 6-2 shows the performance test results of the lithium ion batteries prepared from the negative electrodes of examples 22-24 and comparative examples 5 and 6.

TABLE 6-2

As can be seen from the results of the performance tests of examples 22-24 and comparative examples 5 and 6, B-A is less than or equal to about 0.3 and about 0<I₂/I₁Under the condition of less than or equal to about 1, the cycle performance, the deformation resistance and the rate capability of the lithium ion battery of the negative electrode prepared by silicon oxide satisfying about 0.3 less than or equal to Dn10/Dv50 less than or equal to about 0.6 are better than those of Dn10/Dv50<About 0.3 or about 0.6<Dn10/Dv 50.

7. The negative electrodes of examples 25-28 were prepared by the following method:

(1) the silicon-based anode active material of example 7 was further coated with an oxide MeO_yCoating layer the silicon-based negative active materials of examples 25 to 28 were obtained, and the coating methods of examples 25 to 28 were the same as those of examples 12 to 15, respectively; and

(2) the negative electrodes of examples 25-28 were prepared as described above, and the average sphericities of the silicon-based particles and the graphite particles, which were the same as those of the graphite particles in table 2-2, were about 0.92 and about 0.68, respectively.

Table 7-1 shows the composition and performance parameters of the silicon-based anode active materials in example 7 and examples 25-28.

TABLE 7-1

Wherein "-" means that the substance was not added.

Table 7-2 shows the performance test results of the lithium ion batteries prepared from the negative electrodes in example 7 and examples 25-28.

TABLE 7-2

As can be seen from the test results of example 7 and examples 25-28, B-A is less than or equal to about 0.3 and about 0<I₂/I₁At less than or equal to about 1, the silicon oxide is coated with an oxide MeO_yThe layer may further improve the cycling and/or rate capability and the deformation resistance of the lithium ion battery.

8. The anodes of examples 29-36 were prepared by the following method:

(1) the silicon-based negative active material of example 7 was further coated with the polymer layer containing carbon nanotubes to obtain silicon-based negative active materials of examples 29 to 36, and the coating methods of examples 29 to 36 were the same as the coating methods of examples 16 to 21, respectively: and

(2) the negative electrodes of examples 29-36 were prepared as described above, and the average sphericities of the silicon-based particles and the graphite particles, which were the same as those of the graphite particles in table 2-2, were about 0.92 and about 0.68, respectively.

Table 8-1 shows the compositions of the silicon-based anode active materials with polymer coating layers of examples 29-36.

TABLE 8-1

Wherein "-" means that the substance was not added.

Table 8-2 shows the performance test results of the lithium ion batteries prepared from the negative electrodes of example 7 and examples 29-36.

TABLE 8-2

As can be seen from the test results of example 7 and examples 29-36, B-A is less than or equal to about 0.3 and about 0<I₂/I₁Under the condition of less than or equal to about 1, the cycle performance and/or rate capability and deformation resistance of the lithium ion battery can be further improved by coating the silicon oxide with the polymer layer containing the carbon nano tubes.

9. The negative electrodes of examples 37-41 were prepared by the following method:

(1) the silicon-based anode active material of example 10 was further coated with an oxide MeO_yCoating layer silicon-based negative active materials of examples 37 to 41 were obtained, and the coating methods of examples 37 to 41 were the same as those of examples 12 to 15, respectively; and

(2) the negative electrodes of examples 37-41 were prepared as described above, and the average sphericities of the silicon-based particles and the graphite particles, which were the same as those of the graphite particles in Table 2-2, were about 0.92 and about 0.68, respectively.

Table 9-1 shows the composition and performance parameters of the silicon-based anode active materials in example 10 and examples 37-41.

TABLE 9-1

Wherein "-" means that the substance was not added.

Table 9-2 shows the performance test results of the lithium ion batteries prepared from the negative electrodes in example 10 and examples 37-41.

TABLE 9-2

As can be seen from the results of the performance tests of example 10 and examples 37 to 41, the oxide MeO is coated on the silicon oxide in the same manner as in the case where B-A is less than or equal to about 0.3 and about 0.3. ltoreq. Dn10/Dv 50. ltoreq.0.6_yThe layer may further improve the cycling and/or rate capability and the deformation resistance of the lithium ion battery.

10. The anodes of examples 42-48 were prepared by the following method:

(1) the silicon-based negative active material of example 10 was further coated with a polymer layer containing carbon nanotubes to obtain silicon-based negative active materials of examples 42 to 48, the coating methods of examples 42 to 48 were the same as those of examples 16 to 21, respectively; and

(2) the negative electrodes of examples 42-48 were prepared as described above, and the average sphericities of the silicon-based particles and the graphite particles, which were the same as those of the graphite particles in Table 2-2, were about 0.92 and about 0.68, respectively.

Table 10-1 shows the compositions of the silicon-based anode active materials in example 10 and examples 42-48.

TABLE 10-1

Wherein "-" means that the substance was not added.

Table 10-2 shows the performance test results of the lithium ion batteries prepared from the negative active materials in example 10 and examples 42-48.

TABLE 10-2

From the test results of example 10 and examples 42-48, it can be seen that coating the silicon oxide with the polymer layer containing carbon nanotubes can further improve the cycle performance and/or rate capability and the deformation resistance of the lithium ion battery, while also satisfying that B-A is less than or equal to about 0.3 and about 0.3. ltoreq. Dn10/Dv50 is less than or equal to about 0.6.

11. The anodes of examples 49-58 were prepared by the following method:

(1) the silicon-based negative active materials of examples 49 to 58 were obtained by further coating the polymer layer containing carbon nanotubes with the silicon-based negative active material of example 12, and the coating methods of examples 49 to 58 were the same as those of examples 16 to 21, respectively; and

(2) the negative electrodes of examples 49-58 were prepared as described above, and the average sphericities of the silicon-based particles and the graphite particles, which were the same as those of the graphite particles in Table 2-2, were about 0.92 and about 0.68, respectively.

Table 11-1 shows the compositions of the silicon-based anode active materials in example 12 and examples 49-58.

TABLE 11-1

Wherein "-" means that the substance was not added.

Table 11-2 shows the performance test results of the lithium ion batteries prepared from the negative active materials in example 12 and examples 49-58.

TABLE 11-2

As can be seen from the test results of example 12 and examples 49-58, the surfaces having oxide MeO thereon also satisfied that B-A was less than or equal to about 0.3_yThe silicon oxide of the layer is further coated with a polymer layer containing the carbon nano tubes, so that the cycle performance and/or rate capability and deformation resistance of the lithium ion battery can be further improved.

12. The negative electrodes of examples 59-63 were prepared by the following method:

(1) the silicon-based anode active material of example 23 was further coated with an oxide MeO_yCoating layer silicon-based negative active materials of examples 59 to 63 were obtained, and the coating methods of examples 59 to 63 were the same as those of examples 12 to 15, respectively; and

(2) the negative electrodes of examples 59-63 were prepared as described above, and the average sphericities of the silicon-based particles and the graphite particles, which were the same as those of the graphite particles in Table 2-2, were about 0.92 and about 0.68, respectively.

Table 12-1 shows the composition and performance parameters of the silicon-based anode active materials in example 23 and examples 59-63.

TABLE 12-1

Wherein "-" means that the substance was not added.

Table 12-2 shows the performance test results of the lithium ion batteries prepared from the negative electrodes in example 23 and examples 59-63.

TABLE 12-2

As can be seen from the results of the performance tests of example 23 and examples 59-63, B-A is less than or equal to about 0.3 and about 0<I₂/I₁MeO is coated on the silicon oxide in the presence of not less than about 1 and not less than about 0.3. ltoreq. Dn10/Dv 50. ltoreq.0.6_yThe layer may further improve the cycling and/or rate capability and the deformation resistance of the lithium ion battery.

13. The negative electrodes of examples 64-73 were prepared by the following method:

(1) the silicon-based negative active material of example 23 was further coated with a polymer layer containing carbon nanotubes to obtain silicon-based negative active materials of examples 64 to 73, the coating methods of examples 64 to 73 were the same as those of examples 16 to 21, respectively; and

(2) the negative electrodes of examples 64-73 were prepared as described above, and the average sphericities of the silicon-based particles and the graphite particles, which were the same as those of the graphite particles in Table 2-2, were about 0.92 and about 0.68, respectively.

Table 13-1 shows the compositions of the silicon-based anode active materials in example 23 and examples 64-73.

TABLE 13-1

Wherein "-" means that the substance was not added.

Table 13-2 shows the performance test results of the lithium ion batteries prepared from the negative electrodes in example 23 and examples 64-73.

TABLE 13-2

As can be seen from the results of the performance tests of example 23 and examples 64 to 73, B-A is less than or equal to about 0.3 and about 0<I₂/I₁In the case of less than or equal to about 1 and about 0.3 less than or equal to Dn10/Dv50 less than or equal to about 0.6, coating the silicon oxide with the polymer layer containing carbon nanotubes can further improve the cycle performance and/or rate capability and deformation resistance of the lithium ion battery.

14. The anodes of examples 74-82 were prepared by the following method:

(1) the silicon-based negative active material of example 41 was further coated with a polymer layer containing carbon nanotubes to obtain silicon-based negative active materials of examples 74 to 82, the coating methods of examples 74 to 82 were the same as those of examples 16 to 21, respectively; and

(2) the negative electrodes of examples 74-82 were prepared as described above, and the average sphericities of the silicon-based particles and the graphite particles, which were the same as those of the graphite particles in Table 2-2, were about 0.92 and about 0.68, respectively.

Table 14-1 shows the compositions of the silicon-based anode active materials in example 41 and examples 74-82.

TABLE 14-1

Wherein "-" means that the substance was not added.

Table 14-2 shows the performance test results of the lithium ion batteries prepared from the negative active materials in example 41 and examples 74-82.

TABLE 14-2

As can be seen from the test results of example 41 and examples 74 to 82, in the case where B-A is also satisfied in the same manner as being less than or equal to about 0.3 and about 0.3. ltoreq. Dn10/Dv 50. ltoreq.0.6, the surface has oxide MeO thereon_yThe silicon oxide of the layer coats the polymer layer containing the carbon nano tube, so that the cycle performance and/or the rate capability of the lithium ion battery can be further improved, and the deformation rate of the battery is not obviously changed.

15. The negative electrodes of examples 83-90 were prepared by the following method:

(1) the silicon-based active material of example 63 was further coated with the polymer layer containing carbon nanotubes to obtain silicon-based negative active materials of examples 83 to 90, the coating methods of examples 83 to 90 were the same as those of examples 16 to 21, respectively; and

(2) the negative electrodes of examples 83 to 90 were prepared according to the above-described method, and the average sphericities of the silicon-based particles and the graphite particles, which were the same as those of the graphite particles in table 2 to 2, were about 0.92 and about 0.68, respectively.

Table 15-1 shows the compositions of the silicon-based anode active materials in example 63 and examples 83-90.

TABLE 15-1

Wherein "-" means that the substance was not added.

Table 15-2 shows the performance test results of the lithium ion batteries prepared from the negative electrodes in example 63 and examples 83 to 90.

TABLE 15-2

As can be seen from the results of the performance tests of example 63 and examples 83 to 90, B-A is less than or equal to about 0.3 and about 0<I₂/I₁Less than or equal to about 1 and about 0.3 less than or equal to Dn10/Dv50 less than or equal to about 0.6, to a surface having oxide MeO thereon_yThe silicon oxide of the layer coats the polymer layer containing the carbon nano tube, so that the cycle performance and/or the rate capability of the lithium ion battery can be further improved, and the deformation rate of the battery is not obviously changed.

Reference throughout this specification to "some embodiments," "one embodiment," "another example," "an example," "a specific example," or "some examples" means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. Thus, throughout the specification, descriptions appear, for example: "in some embodiments," "in an embodiment," "in one embodiment," "in another example," "in one example," "in a particular example," or "by example," which do not necessarily refer to the same embodiment or example in this application. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

Although illustrative embodiments have been illustrated and described, it will be appreciated by those skilled in the art that the above embodiments are not to be construed as limiting the application and that changes, substitutions and alterations can be made to the embodiments without departing from the spirit, principles and scope of the application.

Claims (36)

1. An anode material comprising silicon-based particles and graphite particles, wherein the graphite particles have an average sphericity of a, the silicon-based particles have an average sphericity of B, a and B satisfying: B-A is more than 0 and less than or equal to 0.3, and the sphericity refers to the ratio of the shortest diameter to the longest diameter of the particles, wherein the silicon-based particles comprise a silicon composite matrix, the silicon composite matrix comprises nano Si grains, and the size of the nano Si grains is less than or equal to 100 nm.

2. The anode material of claim 1, wherein the silicon-based particles have a maximum intensity value, I, in an X-ray diffraction pattern in the range of 28.0 ° -29.0 ° 2 Θ₂The highest intensity value in the range of 20.5-21.5 is I₁Wherein 0 is<I₂/I₁≤1。

3. The anode material according to claim 1, wherein a particle size distribution of the silicon-based particles satisfies: dn10/Dv50 is more than or equal to 0.3 and less than or equal to 0.6.

4. The anode material of claim 1, wherein the silicon-based particles further comprise an oxide MeO_yLayer of said oxide MeO_yA layer coating at least a portion of the silicon composite matrix, wherein Me comprises at least one of Al, Si, Ti, Mn, V, Cr, Co, or Zr, wherein y is 0.5 to 3; and wherein the oxide MeO_yThe layer comprises a carbon material.

5. The anode material of claim 1, wherein the silicon-based particles further comprise a polymer layer that coats at least a portion of the silicon composite matrix, and the polymer layer comprises a carbon material.

6. The anode material according to claim 2, wherein the silicon-based particles have a particle size distribution satisfying: dn10/Dv50 is more than or equal to 0.3 and less than or equal to 0.6.

7. According to the rightThe anode material of claim 2, wherein the silicon-based particles further comprise an oxide MeO_yLayer of said oxide MeO_yA layer coating at least a portion of the silicon composite matrix, wherein Me comprises at least one of Al, Si, Ti, Mn, V, Cr, Co, or Zr, wherein y is 0.5 to 3; and wherein the oxide MeO_yThe layer comprises a carbon material.

8. The anode material of claim 2, wherein the silicon-based particles further comprise a polymer layer that coats at least a portion of the silicon composite matrix, and the polymer layer comprises a carbon material.

9. The anode material of claim 3, wherein the silicon-based particles further comprise an oxide MeO_yLayer of said oxide MeO_yA layer coating at least a portion of the silicon composite matrix, wherein Me comprises at least one of Al, Si, Ti, Mn, V, Cr, Co, or Zr, wherein y is 0.5 to 3; and wherein the oxide MeO_yThe layer comprises a carbon material.

10. The anode material of claim 3, wherein the silicon-based particles further comprise a polymer layer that coats at least a portion of the silicon composite matrix, and the polymer layer comprises a carbon material.

11. The anode material of claim 4, wherein the silicon-based particles further comprise a polymer layer coating the oxide MeO_yAt least a portion of a layer, and the polymer layer comprises a carbon material.

12. The anode material of claim 6, wherein the silicon-based particles further comprise an oxide MeO_yLayer of said oxide MeO_yA layer coating at least a portion of the silicon composite matrix, wherein Me comprises at least one of Al, Si, Ti, Mn, V, Cr, Co, or Zr, wherein y is 0.5 to 3; and it isThe oxide MeO of (1)_yThe layer comprises a carbon material.

13. The anode material of claim 6, wherein the silicon-based particles further comprise a polymer layer that coats at least a portion of the silicon composite matrix, and the polymer layer comprises a carbon material.

14. The anode material of claim 9, wherein the silicon-based particles further comprise a polymer layer coating the oxide MeO_yAt least a portion of a layer, and the polymer layer comprises a carbon material.

15. The anode material of claim 12, wherein the silicon-based particles further comprise a polymer layer coating the oxide MeO_yAt least a portion of a layer, and the polymer layer comprises a carbon material.

16. The anode material of any one of claims 1, 4, 5, and 7-15, wherein the silicon composite matrix further comprises SiO, SiO₂Or a combination thereof.

17. The anode material according to any one of claims 4, 7, 9, 11, 12, 14, and 15, wherein the oxide MeO_yThe thickness of the layer is 0.5nm to 1000 nm.

18. The anode material according to any one of claims 4, 7, 9, 11, 12, 14 and 15, wherein the weight percentage of Me element is 0.005 wt% to 1.5 wt%.

19. The negative electrode material of any of claims 5, 8, 10, 11, and 13-15, wherein the polymer layer comprises polyvinylidene fluoride and derivatives thereof, carboxymethyl cellulose and derivatives thereof, polyvinyl pyrrolidone and derivatives thereof, polyacrylic acid and derivatives thereof, poly styrene butadiene rubber, polyacrylamide, polyimide, polyamideimide, or any combination thereof.

20. The negative electrode material of any of claims 5, 8, 10, 11, and 13-15, the polymer layer having a weight percentage of 0.05-5 wt%.

21. The anode material according to any one of claims 5, 8, 10, 11, and 13 to 15, wherein the polymer layer has a thickness of 1nm to 150 nm.

22. The anode material of any one of claims 4, 5, and 7-15, wherein the carbon material comprises carbon nanotubes, carbon nanoparticles, carbon fibers, graphene, or any combination thereof.

23. The anode material according to any one of claims 1 to 15, wherein the silicon-based particles have a particle size Dv50 in the range of 2.0 μ ι η to 15 μ ι η.

24. The anode material of any of claims 1 to 15, wherein the silicon-based particles have a specific surface area of 1 to 50m²/g。

25. The anode material of any of claims 1 to 15, wherein the silicon-based particles have an average sphericity of 0.8 to 1.0.

26. The anode material of any of claims 1 to 15, wherein the percentage of the number of silicon-based particles having a sphericity below 0.8 to the total number of silicon-based particles is less than or equal to 10%.

27. The anode material according to any one of claims 1 to 15, wherein the graphite particles have an average sphericity of 0.5 to 0.8.

28. The negative electrode material of any of claims 1 to 15, wherein the percentage of the number of graphite particles having a sphericity of 0.5 to 0.8 to the total number of graphite particles is greater than or equal to 90%.

29. The negative electrode material of any of claims 1-15, wherein the graphite particles are 1330cm in raman spectroscopy analysis^-1Having a scattering peak I₁₃₃₀And at 1580cm^-1Has a scattering peak I₁₅₈₀，I₁₃₃₀/I₁₅₈₀The ratio of (A) to (B) satisfies 0.7 < I₁₃₃₀/I₁₅₈₀＜2.0。

30. The anode material according to any one of claims 1 to 15, wherein the graphite particles have a particle diameter Dv50 of 0.01 to 90 μm.

31. The negative electrode material of any of claims 1-15, wherein the graphite particles have a specific surface area of less than or equal to 30m²/g。

32. The anode material of any one of claims 1-15, wherein the graphite particles have an OI value of 1-30.

33. A negative electrode comprising the negative electrode material of any one of claims 1-32.

34. An electrochemical device comprising the anode of claim 33.

35. The electrochemical device of claim 34, which is a lithium ion battery.

36. An electronic device comprising the electrochemical device of claim 34 or 35.

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