CN117976844A - Negative electrode material, preparation method thereof and battery - Google Patents

Negative electrode material, preparation method thereof and battery Download PDF

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Publication number
CN117976844A
CN117976844A CN202311799936.0A CN202311799936A CN117976844A CN 117976844 A CN117976844 A CN 117976844A CN 202311799936 A CN202311799936 A CN 202311799936A CN 117976844 A CN117976844 A CN 117976844A
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precursor
silicon
anode material
carbon
negative electrode
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车宗洲
肖称茂
何鹏
任建国
贺雪琴
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BTR New Material Group Co Ltd
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BTR New Material Group Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Materials Engineering (AREA)
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  • Battery Electrode And Active Subsutance (AREA)

Abstract

The application provides a negative electrode material, a preparation method thereof and a battery, wherein the negative electrode material comprises a carbon material and an active substance, the carbon material is provided with holes, and the active substance is positioned in the carbon material and/or between the carbon material particles; the active material comprises crystalline silicon and an amorphous silicon layer positioned on at least part of the surface of the crystalline silicon. The negative electrode material provided by the application can effectively inhibit the volume expansion of the negative electrode material and improve the cycle performance of the battery.

Description

Negative electrode material, preparation method thereof and battery
Technical Field
The application relates to the technical field of negative electrode materials, in particular to a negative electrode material, a preparation method thereof and a battery.
Background
The lithium ion battery has the advantages of high energy density, long cycle life, little environmental pollution, no memory effect and the like, and is widely applied to electric automobiles and consumer electronic products. In recent years, the rapid development of electric automobiles has increased the demand for lithium ion batteries with higher energy density, which has prompted researchers to search for battery materials with higher energy density and better cycle performance. The positive and negative electrode materials are the core of the battery, which determines the working efficiency of the battery. Currently, the commercial anode material is graphite, the capacity of which is close to the theoretical upper limit, and the further improvement range is limited, so that development of a new generation of anode material with high energy density is urgently needed. The silicon-based negative electrode material is widely regarded as a next-generation battery negative electrode material, and has the advantages of high capacity, abundant sources, relative safety and the like.
Silicon cathodes are widely regarded as the cathode materials of the next generation batteries, and have the advantages of high capacity, abundant sources, relative safety and the like. However, the silicon cathode has a severe volume expansion effect in the circulation process, so that the material is pulverized and crushed, and the circulation attenuation of the material is rapid. Silicon-carbon composite mode is generally adopted to inhibit the volume expansion of silicon, silicon particles are firstly ground and dispersed to obtain nano silicon, and then the nano silicon is compounded with carbon to prepare the silicon-carbon composite material. Or the carbon matrix is adopted for vapor deposition of silicon, and the prepared anode material has good cycle performance, but the vapor deposition has higher cost and energy consumption and low utilization rate of raw materials.
Disclosure of Invention
The application provides a negative electrode material, a preparation method thereof and a battery, which can realize uniform mixing of amorphous silicon, crystalline silicon and carbon materials, can effectively inhibit volume expansion of the negative electrode material, and can also improve the utilization rate of raw materials and reduce cost.
In a first aspect, the present application provides a negative electrode material comprising a carbon material and an active substance, the active substance being located inside and/or between particles of the carbon material;
the active material comprises crystalline silicon and an amorphous silicon layer positioned on at least part of the surface of the crystalline silicon.
In some embodiments, the negative electrode material has a first characteristic peak at 521cm -1±1cm-1 in a raman spectrum of the negative electrode material, the first characteristic peak having a peak intensity of I 1; the peak intensity of the second characteristic peak at 480cm < -1 > +/-1 cm -1 > is I 2, and I 1/I2 is more than or equal to 0.5 and less than or equal to 2.0.
In some embodiments, the crystalline silicon has a particle size D max. Ltoreq.90 nm.
In some embodiments, the crystalline silicon has a silicon grain size of < 30nm.
In some embodiments, the amorphous silicon layer has a thickness of 5nm to 40nm.
In some embodiments, the carbon material comprises at least one of amorphous carbon and graphitized carbon.
In some embodiments, the active substance further comprises amorphous silicon located inside and/or between the particles of the carbon material.
In some embodiments, the median particle diameter of the negative electrode material is from 1 μm to 50 μm.
In some embodiments, the specific surface area of the negative electrode material is 1m 2/g～4m2/g.
In some embodiments, the negative electrode material has a tap density of 0.9g/cm 3～1.3g/cm3.
In some embodiments, the mass content of the crystalline silicon in the anode material is 10wt% to 50wt%.
In some embodiments, the mass content of the amorphous silicon in the anode material is 10wt% to 40wt%.
In some embodiments, the mass content of the carbon material in the anode material is 20wt% to 70wt%.
In a second aspect, the present application provides a method for preparing a negative electrode material, comprising the steps of:
Performing primary sintering treatment on the mixture of the silicon dioxide and the metal reducing agent to obtain a primary sintering product;
Mixing the primary sintering product with a carbon source precursor, and carbonizing to obtain a first precursor, wherein the first precursor comprises a carbon material, crystalline silicon, a metal simple substance and a metal oxide;
Removing metal simple substance and metal oxide in the first precursor to obtain a second precursor with holes;
and under the negative pressure condition, carrying out vapor deposition on the second precursor by utilizing silicon source gas to obtain the negative electrode material.
In some embodiments, the mass ratio of the silica to the metal reducing agent is 1: (1-1.5).
In some embodiments, the metal reducing agent comprises at least one of magnesium, aluminum, calcium, and zinc.
In some embodiments, the temperature of the primary sintering process is 600 ℃ to 850 ℃.
In some embodiments, the time of the one sintering process is 3 hours to 6 hours.
In some embodiments, the temperature rise rate of the primary sintering process is from 1 ℃/min to 5 ℃/min.
In some embodiments, the primary sintering process is performed under a protective atmosphere comprising at least one of nitrogen, helium, neon, argon, and krypton.
In some embodiments, the carbon source precursor comprises at least one of sucrose, glucose, polyethylene, polyvinyl alcohol, polyethylene glycol, polyaniline, epoxy resin, phenolic resin, furfural resin, acrylic resin, polyethylene oxide, polyvinylidene fluoride, polyacrylonitrile, polyvinyl chloride, and pitch.
In some embodiments, the mass ratio of the primary sintered product to the carbon source precursor is 100 (40-100).
In some embodiments, the carbonization treatment is at a temperature of 700 ℃ to 1000 ℃.
In some embodiments, the carbonization treatment is for a period of time ranging from 3 hours to 8 hours.
In some embodiments, the carbonization treatment has a heating rate of 3 ℃/min to 5 ℃/min.
In some embodiments, the carbonization treatment is performed under a protective atmosphere comprising at least one of nitrogen, helium, neon, argon, and krypton.
In some embodiments, the step of removing the metal simple substance and the metal oxide in the first precursor includes adding the first precursor into an acid solution for acid washing treatment and drying treatment.
In some embodiments, the acid solution comprises at least one of hydrochloric acid, nitric acid, and sulfuric acid.
In some embodiments, the molar ratio of the acid solution added to the metal in the precursor is (1-3): 1.
In some embodiments, the acid solution has a mass concentration of 5wt% to 30wt%.
In some embodiments, the temperature of the drying process is from 70 ℃ to 90 ℃.
In some embodiments, the drying process is for a period of time ranging from 1h to 5h.
In some embodiments, the vapor deposition has a deposition temperature of 400 ℃ to 800 ℃.
In some embodiments, the vapor deposition is performed for a deposition time of 0.5h to 5h.
In some embodiments, the vapor deposition pressure is from 0.1kPa to 10kPa.
In some embodiments, the feedstock of the silicon source gas comprises at least one of monosilane, disilane, monochlorosilane, dichlorosilane, trichlorosilane, and tetrachlorosilane.
In some embodiments, the flow rate of the silicon source gas is 1L/min to 3L/min.
In a third aspect, the present application provides a battery comprising the above negative electrode material or a negative electrode material produced according to the above production method.
The technical scheme of the application has at least the following beneficial effects:
The negative electrode material provided by the application comprises a carbon material and an active substance, wherein the active substance is positioned in the particles of the carbon material and/or among the particles of the carbon material; the active material comprises crystalline silicon and an amorphous silicon layer positioned on the surface of the crystalline silicon. The carbon material in the anode material can serve as an active substance which is connected and distributed in the carbon material through a framework structure, the electron conduction and ion diffusion efficiency of the anode material is enhanced, an amorphous silicon layer is arranged on the surface of crystalline silicon, the volume expansion effect of amorphous silicon energy is low, and the amorphous silicon layer can serve as a buffer material in the volume expansion process of crystalline silicon, so that the volume expansion effect of crystalline silicon is relieved. Therefore, the crystalline silicon with the amorphous silicon layer on the surface is dispersed in the particles of the carbon material and/or among the particles of the carbon material, so that the structural stability of the anode material can be improved, collapse and cracking of the material structure caused by volume expansion in the lithium intercalation and deintercalation process can be reduced, the occurrence of side reaction is effectively reduced, and the cycle performance of the material is improved.
According to the preparation method of the negative electrode material, firstly, the mixture of the silicon dioxide and the metal reducing agent is subjected to primary sintering treatment, the silicon dioxide is used as a raw material, so that the production cost of the negative electrode material can be effectively reduced, and the metal reducing agent can reduce silicon in the silicon dioxide to form crystalline silicon; and then mixing and carbonizing the primary sintering product and the carbon source precursor to obtain a first precursor containing carbon materials, crystalline silicon, metal simple substances and metal oxides. Then, removing the metal simple substance and the metal oxide in the first precursor to obtain a second precursor with holes; and carrying out vapor deposition on the second precursor by utilizing silicon source gas under the negative pressure condition to obtain the negative electrode material. In the vapor deposition process, the crystalline silicon in the second precursor can provide a growth attachment point for amorphous silicon, so that the amorphous silicon can be induced to grow on the surface of the crystalline silicon, the deposition efficiency of silicon source gas is improved, the utilization rate of raw materials is improved, and the production cost is reduced. The cathode material prepared by the preparation method can improve the structural stability, can also reduce collapse and rupture of a material structure caused by volume expansion in the lithium intercalation and deintercalation process, and effectively reduces side reaction, thereby improving the cycle performance of the material.
Drawings
Fig. 1 is a process flow chart of a preparation method of a negative electrode material provided by the application.
Fig. 2 is an XRD pattern of the negative electrode material prepared in example 1 of the present invention.
Fig. 3 is an SEM image of the negative electrode material prepared in example 1 of the present invention.
Fig. 4 is a raman spectrum of the negative electrode material prepared in example 1 of the present invention.
Detailed Description
For better illustrating the present application, the technical scheme of the present application is convenient to understand, and the present application is further described in detail below. The following examples are merely illustrative of the present application and are not intended to represent or limit the scope of the application as defined in the claims.
In a first aspect, the present application provides a method for preparing a negative electrode material, the method comprising the steps of:
step S10, performing primary sintering treatment on the mixture of the silicon dioxide and the metal reducing agent to obtain a primary sintering product;
step S20, mixing and carbonizing the primary sintering product and a carbon source precursor to obtain a first precursor, wherein the first precursor comprises a carbon material, crystalline silicon, a metal simple substance and a metal oxide;
step S30, removing metal simple substance and metal oxide in the first precursor to obtain a second precursor with holes;
And step S40, carrying out vapor deposition on the second precursor by utilizing silicon source gas under the negative pressure condition to obtain the negative electrode material.
According to the preparation method of the negative electrode material, firstly, the mixture of the silicon dioxide and the metal reducing agent is subjected to primary sintering treatment, the silicon dioxide is used as a raw material, so that the production cost of the negative electrode material can be effectively reduced, and the metal reducing agent can reduce silicon in the silicon dioxide to form crystalline silicon; and then mixing and carbonizing the primary sintering product and the carbon source precursor to obtain a first precursor containing carbon materials, crystalline silicon, metal simple substances and metal oxides. Then, removing the metal simple substance and the metal oxide in the first precursor to obtain a second precursor with holes; and then carrying out vapor deposition on the second precursor by utilizing silicon source gas under the negative pressure condition to obtain the negative electrode material. In the vapor deposition process, the crystalline silicon in the second precursor can provide a growth attachment point for amorphous silicon, so that the amorphous silicon can be induced to grow on the surface of the crystalline silicon, the deposition efficiency of silicon source gas is improved, the utilization rate of raw materials is improved, and the production cost is reduced. The negative electrode material prepared by the preparation method can improve the structural stability, can reduce collapse and rupture of the structure of the negative electrode material caused by volume expansion in the lithium intercalation and deintercalation process, and effectively reduces side reaction, thereby improving the cycle performance of the negative electrode material.
The following details the technical scheme of the application:
and step S10, performing primary sintering treatment on the mixture of the silicon dioxide and the metal reducing agent to obtain a primary sintering product.
In some embodiments, the mass ratio of silica to metal reducing agent is 1: (1 to 1.5), specifically, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, or 1:1.5, etc., but other values within the above range are also possible, and the present invention is not limited thereto. A suitable excess of metal reducing agent may ensure that the silica is sufficiently reduced.
In some embodiments, the primary sintered product further comprises a silicon oxide having the formula SiO x, wherein 0.5.ltoreq.x < 2. Specifically, siO x may be SiO 0.5、SiO0.7、SiO0.9、SiO、SiO1.2、SiO1.5、SiO1.8、SiO1.9 or the like, and is not limited herein. The silicon oxygen material may be a material in which silicon particles are dispersed in SiO 2, or a material having a tetrahedral structural unit in which silicon atoms are located at the center of the tetrahedral structural unit and oxygen atoms are located at the four vertices of the tetrahedral structural unit. It is understood that when the content of silica is excessive, it may cause a part of silica to be not completely reduced, resulting in a decrease in the specific capacity of the anode material and a decrease in the energy density.
In some embodiments, the metal reducing agent includes at least one of magnesium, aluminum, calcium, and zinc.
In some embodiments, the median particle diameter of the metal reducing agent is 5 μm to 50 μm, specifically 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, or the like, but other values within the above range are also possible, and the metal reducing agent is not limited thereto.
In some embodiments, the temperature of the primary sintering treatment is 600 to 850 ℃, specifically 600 ℃, 650 ℃, 680 ℃, 700 ℃, 730 ℃, 750 ℃, 780 ℃, 800 ℃, 830 ℃, 850 ℃, or the like, but may be other values within the above range, and the present invention is not limited thereto. It is understood that the silica reacts with the metal reducing agent in a redox reaction at a high temperature, wherein the silica is reduced to form crystalline silicon and the metal reducing agent is oxidized to metal oxide, and a part of the excess metal reducing agent remains in a metal simple substance state.
In some embodiments, the time of the primary sintering treatment is 3h to 6h, specifically, 3h, 4h, 4.5h, 5h, 5.5h, or 6h, or the like, and of course, other values within the above range are also possible, and the present invention is not limited thereto.
In some embodiments, the temperature rising rate of the primary sintering treatment is 1 to 5 ℃ per minute, specifically, 1,2, 3, 4, 4.5, or 5 ℃ per minute, but other values within the above range are also possible, and the present invention is not limited thereto.
In some embodiments, the primary sintering process is performed in a protective atmosphere, the protective gas comprising at least one of nitrogen, helium, neon, argon, and krypton. The reduction is carried out in a protective atmosphere, so that the secondary oxidation of the crystalline silicon obtained by the reduction can be reduced, and the full progress of the oxidation-reduction reaction can be ensured.
Step S20, mixing and carbonizing the primary sintering product and a carbon source precursor to obtain a first precursor, wherein the first precursor comprises a carbon material, crystalline silicon, a metal M simple substance and an oxide of the metal M.
In some embodiments, the mixing process is performed under agitation.
In some embodiments, the mixing time is 0.5h to 3h, specifically, 0.5h, 1h, 1.5h, 2h, 2.5h, or 3h, or the like, but other values within the above range are also possible, and the method is not limited thereto.
In some embodiments, the carbon source precursor comprises at least one of sucrose, glucose, polyethylene, polyvinyl alcohol, polyethylene glycol, polyaniline, epoxy resin, phenolic resin, furfural resin, acrylic resin, polyethylene oxide, polyvinylidene fluoride, polyacrylonitrile, polyvinyl chloride, and pitch.
In some embodiments, the mass ratio of the primary sintered product to the carbon source precursor is 100 (40-100), specifically may be 100:40, 100:50, 100:60, 100:70, 100:80, 100:90 or 100:100, etc., but may also be other values within the above range, and is not limited thereto. It is understood that the mass ratio of the primary sintered product to the carbon source precursor may be adjusted according to the specific capacity required for the anode material, and is not limited herein.
In some embodiments, the carbonization treatment is performed at a temperature of 700 ℃ to 1000 ℃, and the carbonization treatment may be performed at a temperature of 700 ℃, 720 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, 920 ℃, 950 ℃, 970 ℃, 1000 ℃, or the like, without being limited thereto.
In some embodiments, the carbonization time is 3h to 8h, specifically, 3h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, or 8h, etc., without limitation.
In some embodiments, the heating rate of the carbonization treatment is 3 to 5 ℃ per minute, specifically, 3, 3.5, 4, 4.5, or 5 ℃ per minute, or the like, but other values within the above range are also possible, and the present invention is not limited thereto.
In some embodiments, the carbonization treatment is performed under a protective atmosphere, the protective gas comprising at least one of nitrogen, helium, neon, argon, and krypton.
The mass ratio, carbonization temperature, time, heating rate and the like of the carbon source precursor and the primary sintering product are controlled, so that the carbon source precursor and the primary sintering product are fully mixed, the carbon source precursor is coated on the surface of the primary sintering product, the carbon material on the surface of the active substance is beneficial to improving the rate capability of the anode material, and the volume expansion of the anode material is reduced.
In some embodiments, the method further comprises: shaping and screening the carbonized product to obtain a first precursor, wherein the shaping treatment comprises at least one of crushing, grinding, ball milling and air crushing.
And S30, removing the metal simple substance and the metal oxide in the first precursor to obtain a second precursor with holes.
In some embodiments, the step of removing the metal element and the metal oxide in the first precursor includes adding the first precursor to an acid solution for an acid washing treatment and a drying treatment.
It can be understood that, through the acid washing treatment, the oxide of the metal and the metal simple substance in the first precursor are dissolved in the acid solution, at this time, pores are formed around the crystalline silicon of the carbon material, the pore volume of the pores of part of the carbon material is also increased, and the pores can reserve a deposition space for amorphous silicon formed by vapor deposition, so that the specific capacity of the anode material is improved, the expansion effect of the anode material is reduced, and the cycling stability of the anode material is improved.
In some embodiments, the acid solution comprises at least one of hydrochloric acid, nitric acid, and sulfuric acid.
In some embodiments, the molar ratio of the acid solution added to the metal in the precursor is (1-3): 1, a step of; specifically, the ratio of the components can be 1:1, 1.5:1 and 1.8: 1. 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, etc., although the values within the above ranges are also possible and are not limited thereto.
In some embodiments, the mass concentration of the acid solution is 5wt% to 30wt%, specifically, 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, 25wt% or 30wt%, etc., but it is also possible to have a value within the above range, and the present invention is not limited thereto.
After the pickling, the pickling product needs to be continuously ultrasonically washed by deionized water until the washing water is neutral.
In some embodiments, the drying process is for a period of time ranging from 1 hour to 5 hours. Specifically, the drying treatment time may be 1h, 2h, 3h, 4h, 5h, or the like, and is not limited herein.
In some embodiments, the temperature of the drying treatment is 70 to 90 ℃, specifically, 70 ℃,75 ℃, 80 ℃, 81 ℃, 83 ℃,84 ℃, 85 ℃, 86 ℃, 87 ℃, 88 ℃, 89 ℃, or 90 ℃, but may also be other values between the above ranges, and the drying treatment is not limited thereto.
In some embodiments, the manner of drying includes at least one of drying, freeze drying, vacuum drying.
And step S40, carrying out vapor deposition on the second precursor by utilizing silicon source gas under the negative pressure condition to obtain the negative electrode material.
In some embodiments, the deposition temperature of the vapor deposition is 400 to 800 ℃, specifically 400 ℃, 450 ℃, 500 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, or the like, but may be any other value between the above ranges, and the deposition temperature is not limited herein.
In some embodiments, the deposition time of vapor deposition is from 0.5h to 5h; specifically, the reaction time may be 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, or 5h, etc., and is not limited herein.
In some embodiments, the pressure of the vapor deposition is 0.1kPa to 10kPa, specifically, 0.1kPa, 0.5kPa, 1kPa, 2kPa, 3kPa, 4kPa, 5kPa, 6kPa, 8kPa or 10kPa, etc., but may be other values between the above ranges, and the present invention is not limited thereto. The pressure of vapor deposition is controlled within the range, so that the silicon source gas can permeate into the holes of the second precursor and is deposited in the holes, deposition of the silicon source gas on the surface of the second precursor is reduced, side reactions caused by direct contact of silicon particles and electrolyte are reduced, and the cycle performance of the anode material is improved.
In some embodiments, the feedstock of the silicon source gas comprises at least one of monosilane, disilane, monochlorosilane, dichlorosilane, trichlorosilane, and tetrachlorosilane;
In some embodiments, the flow rate of the silicon source gas is 1L/min to 3L/min, specifically, 1L/min, 1.2L/min, 1.5L/min, 1.8L/min, 2L/min, 2.2L/min, 2.5L/min, 2.8L/min, or 3L/min, or the like, but may also be other values between the above ranges, and the flow rate is not limited herein. .
In a second aspect, the present application provides a negative electrode material comprising a carbon material and an active substance, the active substance being located within and/or between particles of the carbon material; the active material comprises crystalline silicon and an amorphous silicon layer positioned on at least part of the surface of the crystalline silicon.
The negative electrode material provided by the application comprises a carbon material and an active substance, wherein the active substance is positioned in the particles of the carbon material and/or among the particles of the carbon material; the active material comprises crystalline silicon and an amorphous silicon layer positioned on the surface of the crystalline silicon. The carbon material in the anode material can serve as an active substance which is connected and distributed in the carbon material through a framework structure, the electron conduction and ion diffusion efficiency of the anode material is enhanced, an amorphous silicon layer is arranged on the surface of crystalline silicon, the volume expansion effect of the amorphous silicon is low, and the amorphous silicon layer can serve as a buffer material in the volume expansion process of the crystalline silicon, so that the volume expansion effect of the crystalline silicon is relieved. Therefore, the crystalline silicon with the amorphous silicon layer on the surface is dispersed in the particles of the carbon material and/or among the particles of the carbon material, so that the structural stability of the anode material can be improved, collapse and cracking of the material structure caused by volume expansion in the lithium intercalation and deintercalation process can be reduced, the occurrence of side reaction is effectively reduced, and the cycle performance of the material is improved.
In some embodiments, the negative electrode material has a first characteristic peak at 521cm -1±1cm-1 in a raman spectrum of the negative electrode material, the first characteristic peak having a peak intensity of I 1; the peak intensity of the second characteristic peak at 480cm < -1 > +/-1 cm -1 > is I 2, and I 1/I2 is more than or equal to 0.5 and less than or equal to 2.0. It can be understood that in the raman spectrum of the negative electrode material, the sharp peak at 521cm -1 is a characteristic peak of crystalline silicon, the wide raman peak at 480cm -1 is a characteristic peak of amorphous silicon, and the lower the ratio of I 1/I2 is, the higher the content of amorphous silicon is.
In some embodiments, the particle diameter D max of the crystalline silicon is not more than 90nm, specifically, 90nm, 80nm, 70nm, 60nm, 50nm, 45nm, 30nm, 25nm, 20nm, 10nm or 5nm, but may be other values between the above ranges, and the present invention is not limited thereto. When the particle diameter of the crystalline silicon exceeds the above range, the volume expansion of the active material is increased, and the cycle performance of the negative electrode material is lowered.
In some embodiments, the average grain size of the crystalline silicon grains is less than 30nm, and may be 29nm, 28nm, 25nm, 23nm, 20nm, 15nm, 10nm, 8nm, 5nm, or 1nm, or other values between the above ranges, without limitation. The particle size of the silicon crystal grains exceeding the above range may increase the volume expansion of the active material and decrease the cycle performance of the negative electrode material.
In some embodiments, the amorphous silicon layer has a thickness of 5nm to 40nm; specifically, the wavelength may be 5nm, 8nm, 10nm, 13nm, 15nm, 20nm, 25nm, 30nm, 35nm, 38nm, 40nm, or the like, but may be any other value between the above ranges, and the present invention is not limited thereto. The thickness of the amorphous silicon layer is controlled in the range, the specific capacity and the first effect of the cathode material can be improved, and the volume expansion of the crystalline silicon can be relieved by the amorphous silicon layer on the surface of the crystalline silicon because the expansion effect of the amorphous silicon layer is lower than that of the crystalline silicon, so that the cycle performance of the cathode material is improved.
In some embodiments, the carbon material comprises at least one of amorphous carbon and graphitized carbon.
In some embodiments, the active material further comprises amorphous silicon located within and/or between the particles of carbon material.
In some embodiments, the median particle size of the anode material is from 1 μm to 50 μm; specifically, the thickness may be 1 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm or the like, but other values within the above range are also possible, and the present invention is not limited thereto. It is understood that the control of the median particle diameter of the anode material within the above range is advantageous for the improvement of the cycle performance of the anode material.
In some embodiments, the specific surface area of the anode material is 1m 2/g～4m2/g; specifically, 1m2/g、1.5m2/g、2m2/g、2.5m2/g、3m2/g、3.5m2/g、3.8m2/g, 4m 2/g, etc. are possible, and other values within the above range are also possible, and the present invention is not limited thereto. The specific surface area of the negative electrode material is controlled within the above range, which is advantageous for improving the initial efficiency and cycle performance of a lithium battery made of the negative electrode material.
In some embodiments, the tap density of the negative electrode material is 0.9g/cm 3～1.3g/cm3, specifically 0.9g/cm3、1.0g/cm3、1.1g/cm3、1.15g/cm3、1.2g/cm3、1.25g/cm3 or 1.3g/cm 3, but may be other values within the above range, and is not limited thereto. The control of the tap of the anode material within the above range is advantageous in improving the energy density of a lithium battery made of the anode material.
In some embodiments, the mass content of the crystalline silicon in the anode material is 10wt% to 50wt%, specifically, may be 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, or 50wt%, etc., without limitation.
In some embodiments, the mass content of amorphous silicon in the anode material is 10wt% to 40wt%; specifically, it may be 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt% or 40wt%, etc., without limitation.
In some embodiments, the mass content of the carbon material in the anode material is 20wt% to 70wt%, specifically may be 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt%, 65wt%, 68wt%, or 70wt%, etc., without limitation.
In a third aspect, the present application provides a battery comprising a negative electrode material as in the first aspect or comprising a negative electrode material as prepared by the method of preparing a negative electrode material as in the second aspect. The battery may be a lithium ion battery, a sodium ion battery, or the like.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.
Example 1
The preparation method of the anode material of the embodiment comprises the following steps:
(1) 400g of nano silicon dioxide powder and 330g of reducing agent (magnesium powder) are taken, placed in a VC mixer to be mixed for 30min, then transferred into a box furnace, ar protective gas is introduced, the temperature is raised to 650 ℃ at the heating rate of 3 ℃/min, and the mixture is naturally cooled after heat preservation for 4h, thus obtaining a primary sintering product.
(2) Uniformly mixing the primary sintering product and asphalt according to the weight ratio of 100:50, placing the mixture in a box furnace, heating to 800 ℃ at the heating rate of 3 ℃/min for carbonization treatment, preserving heat for 3 hours, and crushing to obtain a first precursor.
(3) Dispersing the first precursor in deionized water solution, controlling the solid content of the slurry to be 30%, stirring for 10min, slowly adding HCL solution (the mass concentration is 10 wt%) into the slurry, wherein the molar ratio of the added HCL solution to magnesium in the first precursor is 2:1, continuing stirring for 1h after the addition of the HCL solution is finished, centrifuging, and drying at 80 ℃ for 1h to obtain the second precursor.
(4) And (3) placing 500g of the second precursor in a CVD furnace, wherein the pressure in the CVD furnace is 0.5kPa, the temperature is increased to 600 ℃ at the heating rate of 3 ℃/min, silane gas is introduced, the gas flow is 1.5L/min, the reaction time is 2h, and the reaction is finished, naturally cooling and screening are carried out to obtain the anode material.
Fig. 2 is an XRD pattern of the anode material prepared in example 1 of the present invention, and fig. 3 is an SEM pattern of the anode material prepared in example 1 of the present invention, as shown in fig. 2 to 3, the anode material prepared in this example includes carbon materials and active materials, the active materials being located inside and/or between the particles of the carbon materials; the active material comprises crystalline silicon and an amorphous silicon layer positioned on at least part of the surface of the crystalline silicon.
Fig. 4 is a raman spectrum of the anode material prepared in example 1 of the present invention, as shown in fig. 4, in the raman spectrum of the anode material, the anode material has a first characteristic peak at 521cm -1±1cm-1, and the peak intensity of the first characteristic peak is I 1; there is a second characteristic peak at 480cm-1±1cm -1, the peak intensity of the second characteristic peak is I 2, and I 1/I2 =0.65.
Example 2
Unlike example 1, the following is:
(4) And (3) placing 500g of the second precursor in a CVD furnace, wherein the pressure in the CVD furnace is 0.5kPa, the temperature is increased to 600 ℃ at the heating rate of 3 ℃/min, silane gas is introduced, the gas flow is 1.5L/min, the reaction time is 1h, and the reaction is finished, naturally cooling and screening are carried out to obtain the anode material.
Example 3
Unlike example 1, the following is:
(4) And (3) placing 500g of the second precursor in a CVD furnace, wherein the pressure in the CVD furnace is 0.5kPa, the temperature is increased to 600 ℃ at the heating rate of 3 ℃/min, silane gas is introduced, the gas flow is 1.5L/min, the reaction time is 3h, and the reaction is finished, naturally cooling and screening are carried out to obtain the anode material.
Example 4
Unlike example 1, the following is:
(1) 360g of nano silicon dioxide powder and 366g of reducing agent (magnesium powder) are taken, placed in a VC mixer to be mixed for 30min, then transferred into a box furnace, ar protective gas is introduced, the temperature is raised to 650 ℃ at the heating rate of 3 ℃/min, and the mixture is naturally cooled after heat preservation for 4h, thus obtaining a primary sintering product.
Example 5
Unlike example 1, the following is:
(1) 400g of nano silicon dioxide powder and 270g of reducing agent (magnesium powder) are taken, placed in a VC mixer to be mixed for 30min, then transferred into a box furnace, ar protective gas is introduced, the temperature is raised to 650 ℃ at the heating rate of 3 ℃/min, and the mixture is naturally cooled after heat preservation for 4h, thus obtaining a primary sintering product.
Example 6
Unlike example 1, the following is:
(4) 500g of precursor is placed in a CVD furnace, the pressure in the CVD furnace is 0.1kPa, the temperature is raised to 600 ℃ at the heating rate of 3 ℃/min, silane gas is introduced, the gas flow is 1.5L/min, the reaction time is 0.5h, the reaction is finished, the temperature is naturally reduced, and the anode material is obtained through screening.
Example 7
Unlike example 1, the following is:
(3) Dispersing the first precursor in deionized water solution, controlling the solid content of the slurry to be 30%, stirring for 10min, slowly adding HCL solution (the mass concentration is 10 wt%) into the slurry, wherein the molar ratio of the added HCL solution to magnesium in the precursor is 3:1, continuously stirring for 1h after the addition of the HCL solution is finished, centrifuging, and drying at 75 ℃ for 100min to obtain a second precursor.
Example 8
Unlike example 1, the following is:
(2) Uniformly mixing the primary sintering product and asphalt according to the weight ratio of 100:50, placing the mixture in a box furnace, heating to 1000 ℃ at the heating rate of 3 ℃/min for carbonization treatment, preserving heat for 8 hours, and crushing to obtain a first precursor.
Example 9
Unlike example 1, the following is:
(1) 400g of nano silicon dioxide powder and 330g of reducing agent (aluminum powder) are taken, placed in a VC mixer to be mixed for 30min, then transferred into a box furnace, ar protective gas is introduced, the temperature is raised to 850 ℃ at the heating rate of 3 ℃/min, and the mixture is naturally cooled after heat preservation for 6h, so that a primary sintering product is obtained.
Comparative example 1
Unlike example 1, the following is:
Step (4) is not performed.
The negative electrode material prepared in this comparative example includes a carbon material and crystalline silicon dispersed in the carbon material.
Comparative example 2
Unlike example 1, the following is:
(4) And (3) placing 500g of the second precursor into a sodium hydroxide solution, stirring and reacting for 6-8 hours to dissolve the crystalline silicon, and centrifugally drying to obtain the porous carbon material.
(5) Placing porous carbon in a CVD furnace, wherein the pressure in the CVD furnace is 0.5kPa, heating to 600 ℃ at a heating rate of 3 ℃/min, introducing silane gas, wherein the gas flow is 1.5L/min, the reaction time is 2h, naturally cooling after the reaction is finished, and sieving to obtain the anode material.
The negative electrode material prepared in this comparative example includes a carbon material and amorphous silicon, and the amorphous silicon is located in and on the pores of the carbon material. The testing method comprises the following steps:
(1) The method for testing the specific surface area of the anode material comprises the following steps:
The specific surface area was measured using a microphone trisar 3000 specific surface area and pore size analyzer device.
(2) The granularity of the cathode material is tested in the following manner:
Using the malvern laser particle sizer MS3000, according to the principle that the scattered light intensity distribution generated by particles in each direction depends on the size of the particles, large particles are at a small scattering angle, and small particles are at a large scattering angle, whereby the particle size distribution of the particles is obtained using the scattered light intensity distribution of laser diffraction.
(3) SEM test mode of the negative electrode material:
the surface morphology and particle size of the samples were observed using a Hitachi S4800 scanning electron microscope.
(4) The silicon particle size test mode:
The nano silicon particles are observed through a field emission scanning electron microscope or a transmission electron microscope, the particle sizes of 5-10 nano silicon particles are directly measured through a scale, and the average value of the particle sizes is taken as the final particle size of the nano silicon particles.
(5) XRD test of the negative electrode material:
the model number Panac of Netherlands is adopted: the X' pert PRO equipment tests XRD of the sample and converts the XRD to obtain the grain size of the silicon crystal grains by using a Shelle formula.
(6) Mass content test of silicon element in the anode material:
Drying a sample overnight, placing the sample in a corundum crucible, placing the crucible in a muffle furnace (Nanyang Xinyu SA2-9-17 TP) at 1200 ℃ for 480 minutes, and completing the combustion of carbon and the oxidation reaction of silicon or silicon oxide to silicon dioxide; in the process, the weight m0 of the crucible, the weight m1 of the sample, the total weight m2 of the crucible and the product after firing are recorded, and the silicon content is calculated according to the following formula: si% = (m 2-m 0)/m1×28.09/60.09×100%.
(7) Mass content test of carbon element in the anode material:
The sample is burnt in a high temperature oxygen-enriched state by using a Blucker/Earthwork infrared carbon-sulfur analyzer G4 ICARUS HF/CS-i in Germany, the carbon element is oxidized into carbon dioxide, and enters an infrared detector along with carrier gas, and the content of the carbon element is calculated by quantitatively counting the change of the infrared absorption wavelength intensity of a carbon dioxide signal.
(8) Raman spectrum test:
Using an InVia model instrument test of Renisshaw manufacturer, wherein a first characteristic peak is arranged at 521cm -1±1cm-1 of a Raman spectrum test, and the peak intensity of the first characteristic peak is I 1; the intensity ratio of the first characteristic peak to the second characteristic peak is calculated with the second characteristic peak at 480cm-1 + -1 cm -1.
(9) Testing of the conversion of silane gas:
mass M1/(density ρ of silane gas x gas flow rate L x deposition time h x 28/32) of amorphous silicon in the anode material, mass of amorphous silicon=mass of anode material, mass percentage of amorphous silicon, silane gas density is 1.44g/L.
(10) Electrochemical performance test
Dissolving the anode materials prepared in the examples and the comparative examples in N-methyl pyrrolidone according to the mass ratio of 80:10:10, carboxymethyl cellulose and styrene-butadiene rubber respectively, controlling the solid content to be 50%, coating the anode materials on a copper foil current collector, and vacuum drying to prepare an anode pole piece; a CR2016 button cell is assembled by adopting a metal lithium sheet, 1mol/L lithium hexafluorophosphate LiPF 6/(ethylene carbonate EC+dimethyl carbonate DMC+ethylmethyl carbonate EMC) (v/v=1:1:1) electrolyte, celgard2400 diaphragm and a shell by adopting a conventional production process and a conventional process, wherein the electrochemical performance test current density 1C is equal to 1000mAh/g. Under the condition of 0.1C, the capacity and the first effect of 0.1C are tested, under the condition of 1C, the capacity and the first effect of 1C are tested, and under the condition of 0.1C, the retention rate of 50 charge and discharge cycles and the expansion of the pole piece are tested.
The cycle was repeated for 50 weeks, the thickness of the electrode sheet at this time was H1 measured using a micrometer, and the expansion ratio after 50 cycles was = (H1-H0)/h0×100%.
Repeating the cycle for 50 weeks, and recording the discharge capacity as the residual capacity of the lithium ion battery; capacity retention = remaining capacity/initial capacity 100%.
The results of the above performance tests are shown in table 1 and table 2:
TABLE 1 Performance parameters of the negative electrode materials prepared in examples and comparative examples
TABLE 2 Performance parameters of the batteries prepared in examples and comparative examples
As can be seen from the data in tables 1 and 2, the negative electrode materials prepared in examples 1 to 9 were prepared by subjecting a mixture of silica and a metal reducing agent to a primary sintering treatment, which uses silica as a raw material, so that the production cost of the negative electrode material could be effectively reduced, and the metal reducing agent could reduce silicon in the silica to form crystalline silicon; and then mixing and carbonizing the primary sintering product and the carbon source precursor to obtain a first precursor containing carbon materials, crystalline silicon, metal simple substances and metal oxides. Then, removing the metal simple substance and the metal oxide in the first precursor to obtain a second precursor with holes; and carrying out vapor deposition on the second precursor by utilizing silicon source gas under the negative pressure condition to obtain the negative electrode material. In the vapor deposition process, the crystalline silicon in the second precursor can provide a growth attachment point for amorphous silicon, so that the amorphous silicon can be induced to grow on the surface of the crystalline silicon, the deposition efficiency of silicon source gas is improved, the utilization rate of raw materials is improved, and the production cost is reduced. The cathode material prepared by the preparation method can improve the structural stability, can also reduce collapse and rupture of a material structure caused by volume expansion in the lithium intercalation and deintercalation process, and effectively reduces side reaction, thereby improving the cycle performance of the material.
According to the test data of examples 1 to 5, amorphous silicon is deposited and embedded in the second precursor, so that an amorphous silicon layer is formed on the surface of the crystalline silicon, the first coulombic efficiency and the capacity of the anode material are greatly improved, and the capacity, the first effect, the cycle retention rate and the volume expansion of the composite material can be effectively adjusted by optimizing the addition amount of the amorphous silicon. If the mass content of the amorphous silicon is increased, the expansion of the anode material is increased, and the cycle performance is deteriorated; if the mass content of amorphous silicon is reduced, the first coulombic efficiency of the anode material is reduced. Preferably, the mass content of amorphous silicon in the anode material is 10-32 wt%.
Compared with example 1, in example 4, the content of magnesium in the metal reducing agent is increased when the first precursor is prepared, the intensity of oxidation-reduction reaction is increased, the local reaction temperature is too high, the silicon grain size in crystalline silicon is increased, after magnesium and magnesium oxide are removed by pickling, the silicon grain size is still larger, the volume expansion of the silicon grain is improved, the volume expansion effect of the anode material is increased, and the cycle performance is slightly reduced. Example 5 the magnesium content of the metal reducing agent was reduced during the preparation of the first precursor, the intensity of the redox reaction was reduced, the local temperature was reduced so that the silicon grain size in the prepared crystalline silicon was reduced, but there was some unreduced silicon oxide, the volume expansion effect of the crystalline silicon was reduced during charge and discharge, the cycle performance of the anode material was improved, but the first coulombic efficiency of the anode material was slightly reduced.
The negative electrode material prepared in comparative example 1 does not contain an amorphous silicon layer, and the negative electrode material comprises a carbon material and crystalline silicon dispersed in the carbon material, and although the negative electrode material has good cycle stability and expansion performance, the capacity and first coulombic efficiency of the negative electrode material are obviously reduced.
In the negative electrode material prepared in comparative example 2, the crystalline silicon in the second precursor was removed with sodium hydroxide, the negative electrode material contained only amorphous silicon, amorphous silicon particles were dispersed inside particles of the carbon material and/or between particles of the carbon material, the amorphous silicon content was 26.5% under the same deposition conditions as in example 1, the mass content of amorphous silicon in the negative electrode material was lower, resulting in a lower initial coulombic efficiency of the negative electrode material, and the conversion rate of the silane gas in example 1 was 88% under the same conditions by calculating the conversion rate of the silane gas, indicating that the inclusion of crystalline silicon particles in the precursor could induce the growth of amorphous silicon, improving the efficiency of vapor deposition.
The applicant states that the detailed process equipment and process flows of the present invention are described by the above examples, but the present invention is not limited to, i.e., does not mean that the present invention must be practiced in dependence upon, the above detailed process equipment and process flows. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of raw materials for the product of the present invention, addition of auxiliary components, selection of specific modes, etc., falls within the scope of the present invention and the scope of disclosure.

Claims (10)

1. A negative electrode material, characterized in that the negative electrode material comprises a carbon material and an active substance, the active substance being located inside particles of the carbon material and/or between particles of the carbon material;
the active material comprises crystalline silicon and an amorphous silicon layer positioned on at least part of the surface of the crystalline silicon.
2. The anode material of claim 1, wherein in a raman spectrum of the anode material, the anode material has a first characteristic peak at 521cm -1±1cm-1, the peak intensity of the first characteristic peak being I 1; there is a second characteristic peak at 480cm -1±1cm-1, the peak intensity of which is I 2, and 0.5.ltoreq.I 1/I2.ltoreq.2.0.
3. The anode material according to claim 1, wherein the anode material satisfies at least one of the following characteristics:
(1) The grain diameter D max of the crystalline silicon is less than or equal to 90nm;
(2) The average grain diameter of silicon grains of the crystalline silicon is less than 30nm;
(3) The thickness of the amorphous silicon layer is 5 nm-40 nm;
(4) The carbon material comprises at least one of amorphous carbon and graphitized carbon;
(5) The active material further includes amorphous silicon located within and/or between the particles of the carbon material.
4. The anode material according to claim 1, wherein the anode material satisfies at least one of the following characteristics:
(1) The median particle diameter of the negative electrode material is 1-50 mu m;
(2) The specific surface area of the anode material is 1m 2/g～4m2/g;
(3) The tap density of the anode material is 0.9g/cm 3～1.3g/cm3;
(4) The mass content of the crystalline silicon in the anode material is 10-50 wt%;
(5) The mass content of the amorphous silicon in the anode material is 10-40 wt%;
(6) The mass content of the carbon material in the anode material is 20-70 wt%.
5. The preparation method of the anode material is characterized by comprising the following steps:
Performing primary sintering treatment on the mixture of the silicon dioxide and the metal reducing agent to obtain a primary sintering product;
Mixing the primary sintering product with a carbon source precursor, and carbonizing to obtain a first precursor, wherein the first precursor comprises a carbon material, crystalline silicon, a metal simple substance and a metal oxide;
Removing metal simple substance and metal oxide in the first precursor to obtain a second precursor with holes;
and under the negative pressure condition, carrying out vapor deposition on the second precursor by utilizing silicon source gas to obtain the negative electrode material.
6. The method of manufacture of claim 5, comprising at least one of the following features:
(1) The mass ratio of the silicon dioxide to the metal reducing agent is 1: (1-1.5);
(2) The metal reducing agent comprises at least one of magnesium, aluminum, calcium and zinc simple substances;
(3) The temperature of the primary sintering treatment is 600-850 ℃;
(4) The time of the primary sintering treatment is 3-6 hours;
(5) The heating rate of the primary sintering treatment is 1-5 ℃/min;
(6) The primary sintering treatment is performed under a protective atmosphere, and the protective gas comprises at least one of nitrogen, helium, neon, argon and krypton.
7. The method of manufacture according to claim 5, characterized in that it meets at least one of the following characteristics:
(1) The carbon source precursor comprises at least one of sucrose, glucose, polyethylene, polyvinyl alcohol, polyethylene glycol, polyaniline, epoxy resin, phenolic resin, furfural resin, acrylic resin, polyethylene oxide, polyvinylidene fluoride, polyacrylonitrile, polyvinyl chloride and asphalt;
(2) The mass ratio of the primary sintering product to the carbon source precursor is 100 (40-100);
(3) The carbonization temperature is 700-1000 ℃;
(4) The carbonization treatment time is 3-8 hours;
(5) The heating rate of the carbonization treatment is 3-5 ℃/min;
(6) The carbonization treatment is performed under a protective atmosphere, and the protective gas comprises at least one of nitrogen, helium, neon, argon and krypton.
8. The method according to claim 5, wherein the step of removing the metal element and the metal oxide in the first precursor comprises the steps of adding the first precursor to an acid solution for acid washing and drying; which satisfies at least one of the following characteristics:
(1) The acid solution comprises at least one of hydrochloric acid, nitric acid and sulfuric acid;
(2) The molar ratio of the addition amount of the acid solution to the metal in the precursor is (1 to 3): 1, a step of;
(3) The mass concentration of the acid solution is 5-30wt%;
(4) The temperature of the drying treatment is 70-90 ℃;
(5) The drying treatment time is 1-5 h.
9. The method of manufacture of claim 5, wherein the method meets at least one of the following characteristics:
(1) The deposition temperature of the vapor deposition is 400-800 ℃;
(2) The deposition time of the vapor deposition is 0.5 to 5 hours;
(3) The pressure of the vapor deposition is 0.1kPa to 10kPa;
(4) The raw materials of the silicon source gas comprise at least one of monosilane, disilane, monochloro silicon, dichlorosilane, trichlorosilane and tetrachlorosilane;
(5) The flow rate of the silicon source gas is 1L/min-3L/min.
10. A battery characterized in that the battery comprises the anode material according to any one of claims 1 to 4 or the anode material produced according to the production method of any one of claims 5 to 9.
CN202311799936.0A 2023-12-25 2023-12-25 Negative electrode material, preparation method thereof and battery Pending CN117976844A (en)

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