CN109167026B - Silicon-cobalt composite negative electrode material, preparation method thereof and lithium ion battery - Google Patents
Silicon-cobalt composite negative electrode material, preparation method thereof and lithium ion battery Download PDFInfo
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Abstract
The invention provides a silicon-cobalt composite cathode material, a preparation method thereof and a lithium ion battery, wherein the cathode material is a composite consisting of simple substance silicon and simple substance cobalt, and the content of the simple substance silicon is 20-80 wt%. The preparation method comprises the following steps: adding soluble cobalt salt into an alcohol solvent, heating, stirring and dissolving to obtain a cobalt salt alcohol solution; adding nano silicon powder into a cobalt salt alcohol solution, and performing ultrasonic dispersion to obtain a suspension solution; heating and stirring the suspension solution, and carrying out alcoholysis reaction to obtain a precipitate; and washing, drying and sintering the precipitate to obtain the silicon-cobalt composite cathode material. The silicon-cobalt composite negative electrode material is simple in synthesis process, and the corresponding lithium ion battery has the advantages of high coulombic efficiency and good cycle stability for the first time.
Description
Technical Field
The invention relates to the technical field of lithium ion battery cathode materials, in particular to a silicon-cobalt composite cathode material, a preparation method thereof and a lithium ion battery.
Background
Lithium ion batteries are receiving attention due to their characteristics such as high energy storage density and excellent cycle life, and have a large market share as low-power sources in portable electronic products such as mobile phones and notebooks. Meanwhile, the application of the lithium ion battery is gradually expanded to high-power electric vehicles, large energy storage devices and military equipment (such as unmanned aerial vehicles, satellites and the like) from low-power electronic products, so that higher requirements are provided for the energy storage density, the cycle life, the high-rate charge-discharge characteristic, the low-temperature performance and the safety of the lithium ion battery. The key factors determining the energy storage density, cycle life and other performances of the lithium ion battery are the anode material and the cathode material.
In the current lithium ion battery system, although the capacity of the graphite cathode material is about 1.5-2 times of the capacity of the existing anode material, the energy density of the whole battery is greatly changed by improving the capacity of the existing cathode material under the condition that the capacity of the cathode material does not exceed 1200mAh/g through simulation calculation. Currently, lithium ion battery cathode materials widely used in commercialization are mainly classified into the following two types: (1) artificial graphite and natural modified graphite (C) in hexagonal or rhombohedral layered structures; (2) lithium titanate (Li) of spinel structure4Ti5O12). The two types of materials have obvious advantages in cycle life and safety, but the theoretical specific capacities of the two types of materials are only 370mAh/g and 175mAh/g respectively, the further application of the lithium ion battery is restricted by the lower energy density, although hundreds of types of anode materials are explored at present, the types of the anode materials which can meet the commercial application are very few in practice.
At present, the research focus of the negative electrode material is mainly focused on silicon-based materials, tin-based alloy materials, layered lithium-containing negative electrode materials and transition metal oxide materials, and silicon is the research focus in the aspect of specific capacity so as to reach the ultrahigh specific capacity of 4200 mAh/g. However, the silicon negative electrode material has the following disadvantages in the practical use process: (1) the silicon negative electrode belongs to an alloying lithium intercalation mechanism and generates Li in electrochemical discharge reaction with lithium ions4.4Si, the volume expansion rate is more than 300%, and the volume is rapidly shrunk along with the extraction of lithium ions in the charging process, and the large volume change causes the internal stress of the silicon negative electrode material to be large, so that the material is pulverized and falls off, and the electrochemical performance is deteriorated; (2) the first coulombic efficiency of the silicon cathode is usually lower than 60% due to the formation and irreversible transformation of a large number of SEI films on the surface of the silicon cathode in the first discharging process, and the silicon cathode is difficult to be matched with a positive electrode material to form a full cell; (3) the electrochemical performance of the silicon negative electrode material can be obviously improved after the silicon negative electrode material is modified by the processes of fiberization, doping or carbon coating and the like, but the modification process flow is complex, the production cost is higher, and the silicon negative electrode material is difficult to be put into practical use. Therefore, the development of high-performance lithium ion battery silicon cathode material and the preparation method thereof are to improve the electrochemical performance of the silicon cathode materialChemical properties and the key to driving its application.
Disclosure of Invention
Based on the technical problems in the background art, the invention provides a silicon-cobalt composite negative electrode material, a preparation method thereof and a lithium ion battery.
The silicon-cobalt composite cathode material provided by the invention is a composite consisting of simple substance silicon and simple substance cobalt, wherein the content of the simple substance silicon is 20-80 wt%.
The invention also provides a preparation method of the silicon-cobalt composite cathode material, which comprises the following steps:
s1, adding soluble cobalt salt into the alcohol solvent, heating, stirring and dissolving to obtain a cobalt salt alcohol solution;
s2, adding the nano silicon powder into the cobalt salt alcohol solution obtained in the S1, and performing ultrasonic dispersion to obtain a suspension solution;
s3, heating and stirring the suspension solution obtained in the step S2 to perform alcoholysis reaction to obtain a precipitate;
and S4, washing, drying and sintering the precipitate obtained in the S3 to obtain the silicon-cobalt composite negative electrode material.
The soluble cobalt salt is selected from any one or at least two of cobalt nitrate, cobalt acetate, cobalt acetylacetonate and cobalt chloride; preferably, the alcohol solvent is selected from any one or at least two of ethylene glycol, 1, 2-propylene glycol and glycerol
Preferably, in S1, the concentration of the cobalt salt alcohol solution is 0.1-0.5mol/L, and the heating and stirring temperature is 45-65 ℃.
Preferably, the concentration of the cobalt element in the cobalt salt alcohol solution is 0.1-0.5mol/L, and the heating and stirring temperature is 45-65 ℃.
Preferably, in S2, the nano silicon powder has a particle size of 10-200nm and a purity of more than 99.9%.
Preferably, in S2, the addition amount of the nano silicon powder is 0.25-4 times of the weight of the cobalt element in the cobalt salt.
Preferably, in S2, the ultrasonic dispersion time is 30-60min, and the power of ultrasonic dispersion is preferably 300-800W.
Preferably, in S3, the suspension solution obtained in S2 is heated and stirred under the condition of oil bath to carry out alcoholysis reaction; preferably, the oil bath temperature is 160-240 ℃, the stirring speed is 200-400r/min, and the reaction time is 4-8 h.
Preferably, in S4, the sintering is performed under a reducing atmosphere, preferably, the sintering temperature is 400-600 ℃, and the sintering time is 3-6h, and more preferably, the reducing atmosphere is an atmosphere containing hydrogen and/or carbon monoxide.
The invention further provides a lithium ion battery containing the silicon-cobalt composite negative electrode material.
Preferably, the silicon-cobalt composite negative electrode material is used as an active component of a lithium ion battery negative electrode material, acetylene black is used as a conductive agent, polyvinylidene chloride is used as a binder, the mass ratio of the silicon-cobalt composite negative electrode material to the acetylene black is 7:2:1, and the electrolyte is 1M LiPF6The solution and the metallic lithium are used as counter electrodes.
Compared with the prior art, the invention has the following advantages:
(1) according to the silicon-cobalt composite cathode material, simple cobalt salt and nano silicon powder are subjected to alcoholysis reaction and subsequent heat treatment, a cobalt simple substance with good conductivity is compounded with the nano silicon powder, and the cobalt simple substance and lithium ions do not generate electrochemical reaction, so that the cobalt simple substance is a conductive additive in the charge and discharge process, the electronic conductivity of the electrode material is enhanced, the cobalt simple substance is also a structural support body, the volume change of a silicon cathode in the lithium ion de-intercalation process is relieved, the integrity of the electrode structure is ensured, and better electrochemical performance is obtained.
(2) The preparation method of the silicon-cobalt composite cathode material is simple, the obtained silicon-cobalt composite material is good in consistency, the silicon and cobalt components are uniformly distributed, the component adjustment range is large, and the silicon-cobalt composite cathode material is suitable for batch production. The lithium ion battery cathode material has the advantages of first coulombic efficiency and good cycle stability.
Drawings
FIG. 1 is an XRD pattern of a silicon-cobalt composite anode material obtained in example 1 of the present invention;
FIG. 2 is an SEM image of a silicon-cobalt composite anode material obtained in example 1 of the present invention;
FIG. 3 is a charge-discharge curve diagram of the Si-Co composite anode material obtained in example 1 of the present invention at 0.01-3.0V, 0.1C;
FIG. 4 is a graph showing the cycle performance of the silicon-cobalt composite anode material obtained in example 1 of the present invention;
FIG. 5 is an SEM image of a silicon-cobalt composite anode material obtained in example 2 of the present invention;
FIG. 6 is a charge-discharge curve diagram of the Si-Co composite anode material obtained in example 2 of the present invention at 0.01-3.0V, 0.1C;
fig. 7 is an SEM image of the silicon-cobalt composite negative electrode material obtained in example 3 of the present invention.
Detailed Description
Example 1
The silicon-cobalt composite cathode material is a composite consisting of simple substance silicon and simple substance cobalt, wherein the content of the simple substance silicon is 60 wt%, and the content of the simple substance cobalt is 40 wt%. The preparation method of the silicon-cobalt composite negative electrode material comprises the following steps:
s1, adding cobalt acetate into ethylene glycol, and stirring and dissolving at 50 ℃ to obtain a cobalt salt alcohol solution, wherein the concentration of cobalt element in the cobalt salt alcohol solution is 0.2 mol/L;
s2, adding nano silicon powder with the particle size of 50nm and the purity of more than 99.9% into the cobalt salt alcohol solution obtained in the step S1, wherein the adding amount of the nano silicon powder is 1.25 times of the weight of cobalt elements in the cobalt salt, and performing ultrasonic dispersion for 45min to obtain a suspension solution;
s3, transferring the suspension solution obtained in the step S2 into an oil bath pot, stirring and reacting for 4 hours at the oil bath temperature of 200 ℃, wherein the stirring speed is 300r/min, and carrying out alcoholysis reaction on cobalt acetate to obtain a precipitate;
s4, washing the precipitate obtained in the step S3, drying to obtain a precursor, putting the precursor into a tubular furnace, and performing Ar/H reaction on the precursor2And sintering in a reducing atmosphere at the sintering temperature of 400 ℃ for 4h to obtain the silicon-cobalt composite cathode material.
The silicon-cobalt composite negative electrode material prepared in the embodiment is subjected to phase analysis by using an X-ray diffractometer (Rigaku TTR-iii, Cu ka), the 2 θ scanning range (2 θ) is from 10 ° to 70 °, as shown in fig. 1, the final component of the negative electrode material is a silicon-cobalt simple substance complex, each diffraction peak has high intensity, and good crystallinity is shown. The electron microscope (SEM) of the silicon-cobalt composite negative electrode material prepared in this example was used to perform electron microscope scanning to observe morphology, and the electron microscope (SEM) used was JSM-6390LA, JEOL, manufactured by japan ltd, as shown in fig. 2, the average particle size of the material powder was about 80 to 100nm, the particle size distribution was uniform, and a large number of pores were present, which is advantageous for improving electrochemical performance.
The silicon-cobalt composite anode material prepared in the embodiment was subjected to electrochemical performance test: weighing the positive electrode material, acetylene black and polyvinylidene chloride according to the mass ratio of 7:2:1, adding a proper amount of N-methyl pyrrolidone serving as a size mixing agent, uniformly mixing, coating on a copper foil current collector, drying for 10 hours at 80 ℃ in a vacuum oven, and rolling and punching to obtain the electrode plate. The electrode plate is used as a working electrode, the metal lithium is used as a counter electrode, the Celgard-2400 membrane is used as an isolating membrane, and 1M LiPF6The solution (dissolved in a mixed solution of DEC, EC and 1: 1) is used as an electrolyte, a 2032 type button cell is assembled in a Braun glove box with the water/oxygen content less than 0.1ppm, and then a Shenzhen New Willeber BTS4008 battery test system is used for carrying out charge and discharge test in the voltage range of 0.01-3.0V. Fig. 3 shows the first two charge-discharge curves of the silicon-cobalt composite negative electrode material in the embodiment at 0.01-3.0V and 0.1C, the first discharge specific capacity is 2519.0mAh/g, the first coulombic efficiency is 80.5%, and the high discharge specific capacity and the first coulombic efficiency are exhibited. Fig. 4 is a cycle performance curve of the silicon-cobalt composite negative electrode material at 0.25C (current of the previous three cycles is 0.1C), and it can be found that the negative electrode material has better cycle stability, and the reversible discharge specific capacity of the negative electrode material is still up to 1759mAh/g after 57 cycles.
Example 2
A silicon-cobalt composite cathode material is a composite consisting of simple substance silicon and simple substance cobalt, wherein the content of the simple substance silicon is 40 wt%, and the content of the simple substance cobalt is 60 wt%. The preparation method of the silicon-cobalt composite negative electrode material comprises the following steps:
s1, adding cobalt acetate into an ethylene glycol solvent, and stirring and dissolving at 50 ℃ to obtain a cobalt salt alcohol solution, wherein the concentration of cobalt element in the cobalt salt alcohol solution is 0.2 mol/L;
s2, adding nano silicon powder with the particle size of 50nm and the purity of more than 99.9% into the cobalt salt alcohol solution obtained in the step S1, wherein the adding amount of the nano silicon powder is 0.67 times of the weight of cobalt elements in the cobalt salt, and performing ultrasonic dispersion for 40min to obtain a suspension solution;
s3, transferring the suspension solution obtained in the step S2 into an oil bath pot, stirring and reacting for 6 hours at the oil bath temperature of 220 ℃, wherein the stirring speed is 200r/min, and cobalt acetate undergoes alcoholysis reaction to obtain a precipitate;
s4, washing the precipitate obtained in the step S3, drying to obtain a precursor, putting the precursor into a tubular furnace, and performing Ar/H reaction on the precursor2And sintering in a reducing atmosphere at the sintering temperature of 400 ℃ for 4h to obtain the silicon-cobalt composite cathode material.
The silicon-cobalt composite anode material prepared in this example was subjected to electron microscope scanning for microstructure characterization, and the equipment used was the same as in example 1, as shown in fig. 5, the particle size of the material was increased to about 100-120nm, but the porosity was still high.
The electrochemical performance test of the silicon-cobalt composite negative electrode material prepared in the embodiment is carried out, the electrode preparation method, the battery assembly and the test system of the silicon-cobalt composite negative electrode material are the same as those in the embodiment 1, the previous two-time charging and discharging curves of the silicon-cobalt composite negative electrode material under the conditions of 0.01-3.0V and 0.1C in the embodiment are shown in fig. 6, and as the silicon content in the silicon-cobalt composite negative electrode material in the embodiment is reduced compared with that in the embodiment 1, the first specific discharge capacity is less than 2000mAh/g within the voltage range of 0.01-3.0V, but the first coulombic efficiency is still kept about 80%.
Example 3
A silicon-cobalt composite cathode material is a composite consisting of simple substance silicon and simple substance cobalt, wherein the content of the simple substance silicon is 80wt%, and the content of the simple substance cobalt is 20 wt%. The preparation method of the silicon-cobalt composite negative electrode material comprises the following steps:
s1, adding cobalt acetate into ethylene glycol, and stirring and dissolving at 50 ℃ to obtain a cobalt salt alcohol solution, wherein the concentration of cobalt element in the cobalt salt alcohol solution is 0.1 mol/L;
s2, adding nano silicon powder with the particle size of 50nm and the purity of more than 99.9% into the cobalt salt alcohol solution obtained in the step S1, wherein the adding amount of the nano silicon powder is 4 times of the weight of cobalt elements in the cobalt salt, performing ultrasonic dispersion for 60min, and the power of the ultrasonic dispersion is 500W to obtain a suspension solution;
s3, transferring the suspension solution obtained in the step S2 into an oil bath pot, stirring and reacting for 8 hours at the oil bath temperature of 240 ℃, wherein the stirring speed is 400r/min, and carrying out alcoholysis reaction on cobalt salt to obtain a precipitate;
s4, washing the precipitate obtained in the step S3, drying to obtain a precursor, putting the precursor into a tubular furnace, and performing Ar/H reaction on the precursor2And sintering in a reducing atmosphere at the sintering temperature of 400 ℃ for 4h to obtain the silicon-cobalt composite cathode material.
The silicon-cobalt composite negative electrode material prepared in the embodiment is subjected to electron microscope scanning so as to perform microscopic morphology characterization, the used equipment is the same as that in the embodiment 1, as shown in fig. 7, compared with the embodiment 1 and the embodiment 2, the structural morphology of the composite material is obviously influenced by the large increase of the silicon content in the composite negative electrode material, the particle agglomeration is obvious, large secondary agglomerated particles are generated, the particles are not uniform, and a certain porosity is still maintained.
The electrochemical performance test of the silicon-cobalt composite negative electrode material prepared in the embodiment is carried out, the electrode preparation method, the battery assembly and the test system of the silicon-cobalt composite negative electrode material are the same as those in the embodiment 1, and according to the first two charge-discharge curves of the silicon-cobalt composite negative electrode material under the conditions of 0.01-3.0V and 0.1C, the first discharge specific capacity is 2669.0mAh/g, and the first coulombic efficiency is 75.8%.
Example 4
A silicon-cobalt composite cathode material is a composite consisting of simple substance silicon and simple substance cobalt, wherein the content of the simple substance silicon is 20 wt%, and the content of the simple substance cobalt is 80 wt%. The preparation method of the silicon-cobalt composite negative electrode material comprises the following steps:
s1, adding cobalt nitrate into 1, 2-propylene glycol, and stirring and dissolving at 45 ℃ to obtain a cobalt salt alcohol solution, wherein the concentration of cobalt element in the cobalt salt alcohol solution is 0.5 mol/L;
s2, adding nano silicon powder with the particle size of 10nm and the purity of more than 99.9% into the cobalt salt alcohol solution obtained in the step S1, wherein the addition amount of the nano silicon powder is 0.25 times of the weight of cobalt elements in the cobalt salt, carrying out ultrasonic dispersion for 30min, and the power of the ultrasonic dispersion is 800W to obtain a suspension solution;
s3, transferring the suspension solution obtained in the step S2 into an oil bath pot, stirring for 8 hours at the oil bath temperature of 160 ℃, wherein the stirring speed is 200r/min, and carrying out alcoholysis reaction on cobalt salt to obtain a precipitate;
and S4, washing and drying the precipitate obtained in the step S3 to obtain a precursor, and sintering the precursor in a tubular furnace in an Ar/CO reducing atmosphere at the sintering temperature of 600 ℃ for 3h to obtain the silicon-cobalt composite cathode material.
The electrochemical performance test of the silicon-cobalt composite negative electrode material prepared in the embodiment is carried out, the electrode preparation method, the battery assembly and the test system of the silicon-cobalt composite negative electrode material are the same as those in the embodiment 1, and according to the previous two-time charging and discharging curves of the silicon-cobalt composite negative electrode material under the conditions of 0.01-3.0V and 0.1C, the first discharging specific capacity is 1885.0mAh/g, and the first coulombic efficiency is 83.2%.
Example 5
The silicon-cobalt composite cathode material is a composite consisting of simple substance silicon and simple substance cobalt, wherein the content of the simple substance silicon is 60 wt%, and the content of the simple substance cobalt is 40 wt%. The preparation method of the silicon-cobalt composite negative electrode material comprises the following steps:
s1, adding cobalt chloride into glycerol, and stirring and dissolving at 50 ℃ to obtain a cobalt salt alcohol solution, wherein the concentration of cobalt element in the cobalt salt alcohol solution is 0.3 mol/L;
s2, adding nano silicon powder with the particle size of 100nm and the purity of more than 99.9% into the cobalt salt alcohol solution obtained in the step S1, wherein the addition amount of the nano silicon powder is 1.25 times of the weight of cobalt elements in the cobalt salt, carrying out ultrasonic dispersion for 50min, and the power of the ultrasonic dispersion is 300W to obtain a suspension solution;
s3, transferring the suspension solution obtained in the step S2 into an oil bath pot, stirring for 6 hours at the oil bath temperature of 180 ℃, wherein the stirring speed is 300r/min, and carrying out alcoholysis reaction on cobalt salt to obtain a precipitate;
and S4, washing and drying the precipitate obtained in the step S3 to obtain a precursor, and sintering the precursor in a tubular furnace in an Ar/CO reducing atmosphere at the sintering temperature of 600 ℃ for 3h to obtain the silicon-cobalt composite cathode material.
The electrochemical performance test of the silicon-cobalt composite negative electrode material prepared in the embodiment is carried out, the electrode preparation method, the battery assembly and the test system of the silicon-cobalt composite negative electrode material are the same as those in the embodiment 1, and according to the first two-time charging and discharging curves of the silicon-cobalt composite negative electrode material under the conditions of 0.01-3.0V and 0.1C, the first discharging specific capacity is 2583.0mAh/g, and the first coulombic efficiency is 77.9%.
Example 6
A silicon-cobalt composite cathode material is a composite consisting of simple substance silicon and simple substance cobalt, wherein the content of the simple substance silicon is 50 wt%, and the content of the simple substance cobalt is 50 wt%. The preparation method of the silicon-cobalt composite negative electrode material comprises the following steps:
s1, adding cobalt acetylacetonate into an alcohol solvent, and stirring and dissolving at 65 ℃ to obtain a cobalt salt alcohol solution, wherein the concentration of cobalt element in the cobalt salt alcohol solution is 0.3 mol/L;
s2, adding nano silicon powder with the particle size of 200nm and the purity of more than 99.9% into the cobalt salt alcohol solution obtained in the step S1, wherein the addition amount of the nano silicon powder is 1.25 times of the weight of cobalt elements in the cobalt salt, carrying out ultrasonic dispersion for 60min, and obtaining a suspension solution, wherein the power of the ultrasonic dispersion is 500W;
s3, transferring the suspension solution obtained in the step S2 into an oil bath pot, stirring for 4 hours at the oil bath temperature of 200 ℃, wherein the stirring speed is 300r/min, and carrying out alcoholysis reaction on cobalt salt to obtain a precipitate;
s4, washing the precipitate obtained in the step S3, drying to obtain a precursor, putting the precursor into a tubular furnace, and performing Ar/H reaction on the precursor2And sintering in a reducing atmosphere at the sintering temperature of 500 ℃ for 6h to obtain the silicon-cobalt composite cathode material.
The electrochemical performance test of the silicon-cobalt composite negative electrode material prepared in the embodiment is carried out, the electrode preparation method, the battery assembly and the test system of the silicon-cobalt composite negative electrode material are the same as those in the embodiment 1, and according to the previous two-time charging and discharging curves of the silicon-cobalt composite negative electrode material under the conditions of 0.01-3.0V and 0.1C, the first discharging specific capacity is 2390.0mAh/g, and the first coulombic efficiency is 80.1%.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered as the technical scope of the present invention, and equivalents and modifications thereof should be included in the technical scope of the present invention.
Claims (7)
1. The preparation method of the silicon-cobalt composite negative electrode material is characterized by comprising the following steps of:
s1, adding soluble cobalt salt into the alcohol solvent, heating, stirring and dissolving to obtain a cobalt salt alcohol solution;
s2, adding the nano silicon powder into the cobalt salt alcohol solution obtained in the S1, and performing ultrasonic dispersion to obtain a suspension solution;
s3, heating and stirring the suspension solution obtained in the step S2 to perform alcoholysis reaction to obtain a precipitate;
s4, washing, drying and sintering the precipitate obtained in the step S3 to obtain the silicon-cobalt composite negative electrode material;
the cathode material is a compound consisting of simple substance silicon and simple substance cobalt, wherein the content of the simple substance silicon is 20-80 wt%;
wherein, the sintering in S4 is carried out in a reducing atmosphere, the sintering temperature is 400-600 ℃, and the sintering time is 3-6 h.
2. The method for preparing the silicon-cobalt composite anode material according to claim 1, wherein the soluble cobalt salt is selected from any one or at least two of cobalt nitrate, cobalt acetate, cobalt acetylacetonate and cobalt chloride; the alcohol solvent is any one or at least two of ethylene glycol, 1, 2-propylene glycol and glycerol.
3. The method for preparing the silicon-cobalt composite anode material according to claim 1 or 2, wherein in S1, the concentration of cobalt element in the cobalt salt alcohol solution is 0.1-0.5 mol/L; the heating and stirring temperature is 45-65 ℃.
4. The preparation method of the silicon-cobalt composite anode material according to claim 1 or 2, wherein in S2, the particle size of the nano silicon powder is 10-200nm, and the purity is more than 99.9%; the adding amount of the nano silicon powder is 0.25-4 times of the weight of the cobalt element in the cobalt salt.
5. The preparation method of the silicon-cobalt composite anode material as claimed in claim 1 or 2, wherein in S2, the ultrasonic dispersion time is 30-60min, and the ultrasonic dispersion power is 300-800W.
6. The method for preparing the silicon-cobalt composite anode material as claimed in claim 1 or 2, wherein in S3, the suspension solution obtained in S2 is heated and stirred under the condition of oil bath to carry out alcoholysis reaction; the oil bath temperature is 160-240 ℃, the stirring speed is 200-400r/min, and the reaction time is 4-8 h.
7. The method for producing the silicon-cobalt composite anode material according to claim 1 or 2, wherein in S4, the reducing atmosphere is an atmosphere containing hydrogen and/or carbon monoxide.
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| CN113206231B (en) * | 2021-04-25 | 2022-06-10 | 浙江锂宸新材料科技有限公司 | Silicon-carbon-cobalt composite material and preparation method and application thereof |
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