CN115458715A - Silicon-carbon negative electrode material, preparation method thereof and lithium ion battery - Google Patents

Silicon-carbon negative electrode material, preparation method thereof and lithium ion battery Download PDF

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CN115458715A
CN115458715A CN202110637574.XA CN202110637574A CN115458715A CN 115458715 A CN115458715 A CN 115458715A CN 202110637574 A CN202110637574 A CN 202110637574A CN 115458715 A CN115458715 A CN 115458715A
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silicon
carbon
particles
negative electrode
composite
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孙伟航
李硕
张惠
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Evergrande New Energy Technology Shenzhen Co Ltd
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Evergrande New Energy Technology Shenzhen 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention discloses a silicon-carbon negative electrode material, a preparation method thereof and a lithium ion battery. The silicon-carbon anode material comprises carbon, composite silicon particles and a conductive agent, wherein the carbon, the composite silicon particles and the conductive agent form mixture particles, the composite silicon particles comprise a silicon-based core body and a carbon coating layer coating the silicon-based core body, and the carbon coating layer is doped with ceramic. Therefore, the silicon-carbon negative electrode material provided by the invention has the advantages that the mixture particles are formed by the carbon, the composite silicon particles and the conductive agent, so that the carbon, the composite silicon particles and the conductive agent have a synergistic effect, and the silicon-carbon negative electrode material is endowed with high charge-discharge efficiency, charge-discharge rate, specific capacity and cycle performance. The preparation method of the silicon-carbon cathode material can ensure that the prepared silicon-carbon cathode material has stable structure and electrochemical performance, is high in efficiency and saves the production cost. The lithium ion battery has excellent rate performance and cycle performance, long service life, strong quick charging capability and stable electrochemical performance.

Description

Silicon-carbon negative electrode material, preparation method thereof and lithium ion battery
Technical Field
The invention belongs to the field of lithium ion batteries, and particularly relates to a silicon-carbon negative electrode material, a preparation method thereof and a lithium ion battery.
Background
The development of lithium ion batteries with high energy density, long cycle life and certain rate characteristic is a technical development trend of 3C batteries and power and energy storage batteries, and as a next-generation cathode material of a pure graphite cathode material, a silicon material has an over-theoretical specific capacity of 4200mAh/g and a relatively suitable charge-discharge platform (0.4-0.5V); however, the method has disadvantages in that the volume expansion of up to 300% is generated and the conductivity is poor when the alloying reaction is performed, which may cause pulverization of the negative electrode material, separation of the negative electrode material from the current collector, rapid capacity fading, etc., thereby severely limiting the use in the lithium ion battery.
In view of this, it is a hot spot of current research to improve the performance of a silicon-based negative electrode material by means of carbon coating and the like, and reducing the volume expansion rate by sacrificing theoretical specific capacity for preparing a silicon-oxygen material, aiming at effectively relieving the great volume change of the silicon material in the charging and discharging process. Although there are reports that the modified silicon material is publicly reported at present, the energy density, the charge-discharge efficiency, the rate capability or/and the cycle performance of the modified silicon material disclosed at present are adversely affected, and many preparation methods cannot achieve the feasibility of industrialization, for example, in the publicly reported porous nuclear silicon and the preparation method thereof, the HF etching mode is adopted in Si/SiO etching 2 Formation of porous core silicon on the mixture, but this method does not guarantee all SiO 2 Etching and removing; in the disclosed silicon-carbon material, nano silicon particles are changed into nano silicon spheres through a series of treatments and then carbon coating is carried out, so that the production cost of the material is greatly increased; in another disclosed silicon-carbon material, siC is pyrolyzed into a silicon material at a high temperature of 2200-2400 ℃, and a vacuum environment is required, so that the cost is high. In one part of the disclosed nano silicon alloy material, the negative electrode material comprises 40-6 percent0% wt of the nano-silicon alloy material, the cost of the material is greatly increased.
Therefore, if the silicon carbon material is improved, the charging and discharging efficiency, the cycle life and the charging and discharging rate are considered and the economic cost is reduced on the premise of ensuring the energy density, the problem which is continuously overcome by the field is solved.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a silicon-carbon negative electrode material and a preparation method thereof, so as to solve the technical problems that the existing silicon-carbon material is not ideal in charge-discharge efficiency, rapid charge capacity and cycle performance or cannot give consideration to both, and is high in cost.
The invention also aims to provide a lithium ion battery to solve the technical problems of first efficiency, non-ideal quick charging capability and cycle performance and high cost of the conventional lithium ion battery containing the silicon-carbon material.
In order to achieve the above object, according to one aspect of the present invention, a silicon carbon anode material is provided. The silicon-carbon negative electrode material comprises carbon, composite silicon particles and a conductive agent, wherein the carbon, the composite silicon particles and the conductive agent form mixture particles, the composite silicon particles comprise a silicon-based core body and a carbon coating layer coating the silicon-based core body, and the carbon coating layer is doped with ceramic. In the mixture particles of the silicon-carbon negative electrode material in the embodiment of the invention, the composite silicon particles use the silicon-based material as the core body to endow the silicon-carbon negative electrode material with high specific capacity characteristic, and use the carbon material containing ceramic as the coating layer to endow the coating layer with excellent mechanical property to construct the anti-expansion functional layer with good mechanical property, so that the volume expansion effect of the silicon-based core body in the charge and discharge process can be effectively resisted, the composite silicon particles are endowed with excellent volume and structure stability performance, and the composite silicon particles are endowed with excellent cycle performance. The carbon and the conductive agent contained in the mixture particles and the carbon coating layer contained in the composite silicon particles construct a good conductive system, so that the silicon-carbon negative electrode material has low resistance and high conductivity, and the silicon-carbon negative electrode material has high charge-discharge efficiency and charge-discharge multiplying power. Therefore, the silicon-carbon negative electrode material provided by the embodiment of the invention has the advantages that the mixture particles are formed by the carbon, the composite silicon particles and the conductive agent, so that the carbon, the composite silicon particles and the conductive agent have a synergistic effect, and the silicon-carbon negative electrode material is endowed with high charge-discharge efficiency, charge-discharge rate, specific capacity and cycle performance.
Further, the mass ratio of carbon, composite silicon particles and the conductive agent contained in the silicon-carbon negative electrode material is 85-70: (10): (5-20). By controlling and adjusting the proportion of the carbon, the composite silicon particles and the conductive agent, the conductivity and the specific capacity of the silicon-carbon negative electrode material are improved, so that the silicon-carbon negative electrode material has high charge-discharge efficiency, charge-discharge rate, specific capacity and other performances.
Further, carbon is used as a carrier, and the composite silicon particles and the conductive agent are dispersed in the carrier. The composite silicon particles and the conductive agent are dispersed in the carbon carrier, so that the composite silicon particles and the conductive agent can be dispersed more uniformly, and the contact area of the composite silicon particles and carbon can be increased, thereby improving the conductivity of the silicon-carbon cathode material.
Further, the carbon is cracked carbon. Thus, the structural stability of the mixture particle including carbon, composite silicon particles and the conductive agent can be improved.
Further, the particle size of the composite silicon particles is in the nanometer range. By controlling the particle size of the composite silicon particles, the dispersibility of the composite silicon particles in the mixture particles can be improved, and the particle size of the silicon-carbon negative electrode material can be controlled.
Further, the conductive agent includes at least one of carbon nanotubes, super p, graphene, and graphite fine powder. The conductive agents have excellent conductive performance, and when the conductive agents are carbon nano tubes, a three-dimensional conductive network structure can be formed in the mixed particles or secondary particles constructed by the mixed particles by one-position structures of the conductive agents, so that the conductive performance is improved, the structural stability of silicon-carbon negative electrode material particles is improved, and the cycle performance of the silicon-carbon negative electrode material is improved.
Further, the silicon nucleus is elemental silicon. The elemental silicon is used as a core body, the first effect is improved, the volume expansion is low, and the first effect performance and the cycle performance of the silicon-carbon cathode material can be improved.
Further, the ceramic includes at least one of alumina, silicon carbide, and titanium dioxide. These a little pottery have good mechanical properties, improve the anti silicon base nuclear body volume expansion effect of carbon coating, can improve the effect of the isolated electrolyte of carbon coating moreover, avoid electrolyte direct and silicon base nuclear body contact, improve silicon carbon negative electrode material's electrochemical properties.
Further, the thickness of the carbon coating layer is 5-8nm. The carbon coating layer with the thickness has relatively excellent mechanical property and the performance of preventing the electrolyte from contacting with the silicon core body.
Further, the silicon carbon anode material also comprises a capacity extender, and the capacity extender is mixed with the carbon, the composite silicon particles and the conductive agent. The existence of the capacity replenisher can effectively fill up micropores possibly existing in carbon, so that the silicon-based core body is assisted to improve the capacity of the silicon-carbon negative electrode material, the specific capacity of the silicon-carbon negative electrode material is improved, meanwhile, the carbon and the conductive agent are assisted to construct a three-dimensional conductive system, the conductive performance of the silicon-carbon negative electrode material is improved, and the quick charging capacity of the silicon-carbon negative electrode material is improved.
Further, the content of the capacity extender in the silicon-carbon anode material is 5% -10%.
Still further, the capacity extender includes graphite.
The content and the type of the capacity extender are controlled, so that the function of the capacity extender is improved, the conductivity of the silicon-carbon negative electrode material is improved, and the quick charging capability of the silicon-carbon negative electrode material is improved.
In another aspect of the invention, a preparation method of the silicon-carbon negative electrode material is provided. The preparation method of the silicon-carbon negative electrode material comprises the following steps:
providing composite silicon particles; the composite silicon particles comprise a silicon-based core body and a carbon coating layer coating the silicon-based core body, and the carbon coating layer is doped with ceramic;
mixing the composite silicon particles with a conductive agent and a first carbon source to obtain a mixed material;
and carrying out first carbonization treatment on the mixed material.
Thus, the preparation method of the silicon-carbon negative electrode material can effectively ensure that the composite silicon particles, the conductive agent and the carbon generated by carbonization are uniformly dispersed, thereby ensuring that the carbon, the composite silicon particles and the conductive agent contained in the prepared silicon-carbon negative electrode material play a role in synergism, endowing the prepared silicon-carbon negative electrode material with high charge-discharge efficiency, charge-discharge rate, specific capacity and cycle performance, and simultaneously ensuring that the material particle structure has good mechanical properties. In addition, the preparation method of the silicon-carbon cathode material can ensure that the prepared silicon-carbon cathode material has stable structure and electrochemical performance, is high in efficiency and saves the production cost.
Further, the composite silicon particles, the conductive agent and the first carbon source are mixed according to the mass ratio of 10: (5-20): (85-70) mixing treatment. By controlling and optimizing the mixing proportion of the three components, the mass proportion of the composite silicon particles, the conductive agent and the carbon contained in the generated silicon-carbon negative electrode material is controlled, and the charge-discharge efficiency, the charge-discharge rate, the specific capacity and other performances of the prepared silicon-carbon negative electrode material are improved.
Further, before the step of carrying out first carbonization treatment on the mixed material, preparing the mixed material into a mixture dispersion liquid; then carrying out spray drying granulation on the mixture dispersion liquid to obtain mixture particles; the mixture particles are then subjected to a first carbonization treatment. By carrying out spray granulation on the mixed material, on one hand, raw materials of all components can be uniformly mixed, and the particle size of the formed precursor particles is complete and uniform.
Further, the composite silicon particles are prepared according to a method comprising the following steps:
mixing the silicon-based particles with a second carbon source containing a ceramic precursor to form a coating layer on the surface of the silicon-based particles by the second carbon source containing the ceramic precursor to obtain a composite silicon particle precursor;
and carrying out second carbonization treatment on the composite silicon particle precursor to obtain the composite silicon particles.
The composite silicon particles prepared by the method have complete carbon coating layers, strong mechanical property and uniform particles.
Still further, the silicon-based particles include at least one of elemental silicon, silicon carbide, and silica.
Still further, the second carbon source comprises at least one of an organic aluminum source and an organic titanium source.
Further, the temperature of the second carbonization treatment is 600 to 900 ℃.
Through the selection of raw materials of the composite silicon particles and the control of the carbonization temperature, ceramic components are uniformly dispersed in the generated carbon coating layer, and the generated carbon coating layer is endowed with good mechanical property and electrolyte isolation property, so that the prepared composite silicon particles have high specific capacity and good particle mechanical property.
Further, the first carbon source comprises at least one of asphalt, biomass charcoal, polyethylene glycol, PVP, citric acid and phenolic resin; and/or
Further, the temperature of the first carbonization treatment is 600 to 900 ℃.
And the related electrochemical performance of the silicon-carbon negative electrode material is improved by controlling the type of the first carbon source and the carbonization treatment temperature.
In another aspect of the present invention, a lithium ion battery is provided, which includes a negative electrode, the negative electrode includes a current collector and a negative electrode active layer bonded on the surface of the current collector, and the negative electrode active layer contains the above silicon carbon negative electrode material or the silicon carbon negative electrode material prepared by the above preparation method of the silicon carbon negative electrode material. Therefore, the lithium ion battery contains the silicon-carbon negative electrode material, so that the negative electrode has good cycle performance and low internal resistance, and the lithium ion battery has excellent rate performance and cycle performance, long service life, strong quick charging capability and stable electrochemical performance.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic structural diagram of a silicon-carbon negative electrode material according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of composite silicon particles contained in a silicon-carbon negative electrode material according to an embodiment of the present invention;
fig. 3 is a schematic flow chart of a method for preparing a silicon-carbon negative electrode material according to an embodiment of the invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application more clearly apparent, the present application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of and not restrictive on the broad application.
In this application, the term "and/or" describes an association relationship of associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a is present alone, A and B are present simultaneously, and B is present alone. Wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.
In this application, "at least one" means one or more, "a plurality" means two or more. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, "at least one (one) of a, b, or c," or "at least one (one) of a, b, and c," may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, and c may be single or plural, respectively.
It should be understood that, in various embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, some or all of the steps may be executed in parallel or executed sequentially, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.
The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the examples of this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
The weight of the related components mentioned in the description of the embodiments of the present application may not only refer to the specific content of each component, but also represent the proportional relationship of the weight among the components, and therefore, the content of the related components is scaled up or down within the scope disclosed in the description of the embodiments of the present application as long as it is scaled up or down according to the description of the embodiments of the present application. Specifically, the mass described in the specification of the embodiments of the present application may be a mass unit known in the chemical industry field such as μ g, mg, g, kg, etc.
The terms "first" and "second" are used for descriptive purposes only and are used for distinguishing purposes such as substances from one another, and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. For example, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX, without departing from the scope of embodiments of the present application. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.
In one aspect, embodiments of the present invention provide a silicon carbon negative electrode material. As shown in fig. 1 and 2, the silicon-carbon negative electrode material according to the embodiment of the present invention includes carbon 10, composite silicon particles 20, and a conductive agent 30, and the carbon 10, the composite silicon particles 20, and the conductive agent 30 form mixture particles.
The carbon 10 and the conductive agent 30 contained in the silicon-carbon negative electrode material in the embodiment of the invention are communicated to construct a good conductive system, and the composite silicon particles 20 are dispersed in the conductive system, so that the conductive performance of the composite silicon particles 20 is effectively improved, the silicon-carbon negative electrode material is endowed with low resistance and high conductive performance, and the silicon-carbon negative electrode material is endowed with high charge-discharge efficiency and charge-discharge rate.
In the embodiment, the carbon 10 is a carrier, that is, the content of the carbon 10 is controlled so that it constitutes a carrier component of the mixture particles, so that the composite silicon particles 20 and the conductive agent 30 are dispersed in the carrier. The carbon 10 is used as a carrier, and the composite silicon particles 20 and the conductive agent 30 are dispersed in the carbon 10 carrier, so that on one hand, the composite silicon particles 20 and the conductive agent 30 can be more uniformly dispersed, and the contact area of the composite silicon particles 20 and the carbon can be increased, so that the conductive performance of the silicon-carbon negative electrode material is improved, and the carbon carrier can also improve the mechanical property of the mixture particles.
In the examples, carbon 10 is cracked carbon. Thus, the cracking carbon can be fully filled between the composite silicon particles 20 and the conductive agent 30 to play a role of carrier and conductive bonding, thereby improving the conductive performance of the silicon-carbon negative electrode material and improving the structural stability of the mixture particles.
In an embodiment, the conductive agent 30 includes at least one of carbon nanotubes, super p, graphene, and graphite micro powder. The conductive agents have excellent conductive properties. And when the conductive agent 30 is a carbon nanotube, a three-dimensional conductive network structure can be formed in the mixed particles or the secondary particles constructed by the mixed particles in one-dimensional structure, so that the conductive performance is improved, the structural stability of the silicon-carbon negative electrode material particles is improved, and the cycle performance of the silicon-carbon negative electrode material is improved.
The structure of the composite silicon particle 20 contained in the silicon-carbon anode material according to the embodiment of the present invention is shown in fig. 2, where the composite silicon particle 20 includes a silicon-based core body 21 and a carbon coating layer 22 coating the silicon-based core body 21, and the carbon coating layer 22 is doped with ceramic. Thus, the composite silicon particle 20 uses a silicon-based material as a core body to endow the silicon-carbon negative electrode material with high specific capacity characteristic, uses a carbon material containing ceramic as a coating layer to endow the coating layer 22 with excellent mechanical property, and constructs an anti-expansion functional layer with good mechanical property, so that the volume expansion effect of the silicon-based core body 21 in the charge and discharge process can be effectively resisted, the composite silicon particle is endowed with excellent volume and structure stability performance, and the composite silicon particle is endowed with excellent cycle performance. The carbon contained in the carbon coating layer 22 imparts excellent electrical conductivity to the carbon coating layer 22. And a good conductive system is constructed by the silicon carbon negative electrode material, the carbon 10 and the conductive agent 30 contained in the silicon carbon negative electrode material, so that the effect of conductivity enhancement is achieved, the silicon carbon negative electrode material is endowed with low resistance and high conductivity, and the silicon carbon negative electrode material is endowed with high charge and discharge efficiency and charge and discharge multiplying power. Therefore, the silicon-carbon negative electrode material provided by the embodiment of the invention comprises the carbon 10, the composite silicon particles 20 and the conductive agent 30 to form mixture particles, so that the carbon 10, the composite silicon particles 20 and the conductive agent 30 have a synergistic effect, and the silicon-carbon negative electrode material is endowed with high charge-discharge efficiency, charge-discharge rate, specific capacity and cycle performance.
The silicon-based core body 21 is used as a main material of the silicon-carbon negative electrode material with a main specific capacity, and the silicon-carbon negative electrode material is endowed with a high specific capacity characteristic, the material of the silicon-based core body 21 can be a conventional silicon-based material, such as at least one of silicon monoxide, silicon carbide and elemental silicon, and in the embodiment of the invention, elemental silicon is ideally selected. The silicon-based materials have high specific capacity, wherein the simple substance silicon has high specific capacity, can improve the first effect, has low volume expansion, and can improve the first effect performance and the cycle performance of the silicon-carbon cathode material.
In the examples, the particle size of the silicon core body 21 is in the micrometer range, and D90 is not less than 100nm. In addition, the silicon-based core body 21 may be a primary particle or a secondary particle formed of the primary particle.
In the embodiment, the thickness of the carbon coating layer 22 is 5-8nm, and in the specific embodiment, the thickness of the carbon coating layer 22 is 5nm, 5.5nm, 6nm, 6.5nm, 7nm, 7.5nm, 8nm, and other typical and non-limiting thicknesses. The carbon coating layer 22 of this thickness has relatively excellent mechanical properties and a property of blocking the contact of the electrolyte with the silicon core body.
In some embodiments, the ceramic distributed in the carbon coating 22 includes at least one of alumina, silicon carbide, and titanium dioxide, and further includes silicon oxide. These some pottery have good mechanical properties, improve the anti silicon base nuclear body 21 volume expansion effect of carbon coating 22, can improve the effect of the isolated electrolyte of carbon coating 22 moreover, avoid electrolyte direct and silicon base nuclear body 21 contact, improve silicon carbon negative electrode material's electrochemical performance.
In the examples, the particle size of the composite silicon particle 20 is in the nanometer range, for example, the D50 is 80-300nm, and in the specific examples, the D50 is a typical and non-limiting particle size of 80nm, 100nm, 120nm, 140nm, 160nm, 180nm, 200nm, 220nm, 240nm, 260nm, 280nm, 300nm, and the like. By controlling the particle size of the composite silicon particles 20, the dispersibility thereof in the mixture particles can be improved and the particle size of the silicon carbon anode material can be controlled.
The composite silicon particles 20 may be primary particles or secondary particles formed of primary particles.
Based on the interaction relationship and action of the carbon 10, the composite silicon particles 20 and the conductive agent 30 contained in the silicon-carbon negative electrode material, in the embodiment, the mass ratio of the carbon 10, the composite silicon particles 20 and the conductive agent 30 is 10: (5-20): (85-70), and carrying out carbonization treatment, specifically the following mixing ratio in the preparation method of the silicon-carbon negative electrode material. By controlling and adjusting the proportion of the carbon 10, the composite silicon particles 20 and the conductive agent 30, the conductivity and the specific capacity of the silicon-carbon negative electrode material are improved, so that the silicon-carbon negative electrode material has high charge-discharge efficiency, charge-discharge rate, specific capacity and other performances.
Based on the silicon carbon anode material in each of the above embodiments, in the embodiment, the silicon carbon anode material further includes a capacity extender, as shown in fig. 1, the capacity extender 40 is mixed with the carbon 10, the composite silicon particles 20 and the conductive agent 30, that is, the capacity extender 40 is mixed with the carbon 10, the composite silicon particles 20 and the conductive agent 30. The existence of the capacity extender 40 can effectively fill up micropores which may exist in the carbon 10, especially when the carbon 10 is sintered carbon, the capacity extender 40 can effectively fill up micropores which exist in the sintered carbon, so as to assist the silicon core body 21 to improve the capacity of the silicon-carbon negative electrode material, improve the specific capacity of the silicon-carbon negative electrode material, and simultaneously assist the carbon 10 and the conductive agent 30 to construct a three-dimensional conductive system, improve the conductive performance of the silicon-carbon negative electrode material, and improve the rapid charging capability of the silicon-carbon negative electrode material.
In the examples, the content of the capacity extender 40 in the silicon-carbon anode material is 5-10%, and in the specific examples, the content of the capacity extender 40 in the silicon-carbon anode material is 5%, 6%, 7%, 8%, 9%, 10%, and the like, which are typical and non-limiting contents. In other embodiments, the capacity extender 40 includes graphite. By controlling the content and the type of the capacity extender 40, the above-mentioned function of the capacity extender is improved, so that the conductivity of the silicon-carbon negative electrode material is improved, and the quick charging capability of the silicon-carbon negative electrode material is improved.
Based on the above, the silicon-carbon negative electrode material provided by the embodiment of the invention has a synergistic effect by forming the mixture particles including the carbon 10, the composite silicon particles 20 and the conductive agent 30, and the silicon-carbon negative electrode material has high charge and discharge efficiency, charge and discharge rate, specific capacity and cycle performance.
On the other hand, the embodiment of the invention provides a preparation method of the silicon-carbon anode material in the embodiment of the invention. The preparation method of the silicon-carbon anode material of the embodiment of the invention has the process flow as shown in fig. 3, and comprises the following steps:
s01: providing composite silicon particles;
s02: mixing the composite silicon particles with a conductive agent and a first carbon source to obtain a mixed material;
s03: and carrying out first carbonization treatment on the mixed material.
Wherein, in step S01, the composite silicon particles are the composite silicon particles 20 described above and shown in fig. 2. Therefore, the composite silicon particle in step S01 includes the silicon-based core body 21 and the carbon coating layer 22 coating the silicon-based core body 21, and the carbon coating layer 22 is doped with ceramic. For economy of disclosure, the structure and composition of the composite silicon particles in step S01 will not be described in detail herein.
In the examples, the composite silicon particles were prepared according to a method comprising the steps of:
s011: mixing the silicon-based particles with a second carbon source containing a ceramic precursor to form a coating layer on the surface of the silicon-based particles by the second carbon source containing the ceramic precursor to obtain a composite silicon particle precursor;
s012: and carrying out second carbonization treatment on the composite silicon particle precursor to obtain the composite silicon particles.
In step S011, the silicon-based particles may be the silicon-based core bodies 21 contained in the composite silicon particles 20, and in the embodiment, the silicon-based particles may be conventional silicon-based materials with a nano-particle size range, such as at least one of elemental silicon, silicon carbide, and silicon monoxide, and further elemental silicon particles.
The second carbon source containing the ceramic precursor may be a mixture of the ceramic precursor and a carbon source, or a carbon-containing ceramic precursor, and in an embodiment, when the second carbon source containing the ceramic precursor is a mixture of the ceramic precursor and a carbon source, the ceramic precursor includes at least one ceramic precursor of aluminum oxide, silicon carbide, and titanium dioxide. The second carbon source comprises at least one of an organic aluminum source and an organic titanium source.
When the second carbon source containing the ceramic precursor is a carbon-containing ceramic precursor, the carbon-containing ceramic precursor includes at least one of an organic aluminum source and an organic titanium source. Wherein the organic aluminum source includes, but is not limited to, at least one of aluminum ethoxide, aluminum isopropoxide, aluminum alkoxide, and the like.
The mixing treatment in step S011 may be any mixing manner as long as it can achieve coating of the second carbon source containing the ceramic precursor on the surface of the silicon-based particles, for example, the second carbon source containing the ceramic precursor and the silicon-based particles are prepared into a dispersion liquid, and the dispersion liquid is subjected to mixing treatment, such as ball milling or sand milling, so that the second carbon source containing the ceramic precursor forms a coating layer on the surface of the silicon-based particles, thereby obtaining the composite silicon particle precursor.
In addition, the mixing ratio of the silicon-based particles and the second carbon source containing the ceramic precursor can control the thickness of the carbon coating layer contained in the composite silicon particles, for example, the thickness of the carbon coating layer is controlled to be the thickness of the carbon coating layer 22 contained in the composite silicon particles 20 by the mixing ratio of the silicon-based particles and the second carbon source containing the ceramic precursor.
The second carbonization treatment in step S012 is to subject the composite silicon particle precursor prepared in step S011 to a carbonization treatment so that a second carbon source is carbonized and the ceramic precursor forms a ceramic, thereby forming the above composite silicon particles 20. In the examples, the temperature of the second carbonization treatment is 600 to 900 ℃, and in the specific examples, the temperature of the second carbonization treatment is 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃ and other typical and non-limiting temperatures. The temperature of the second carbonization treatment can be flexibly adjusted and controlled according to the types of the second carbon source and the ceramic precursor. In addition, the second carbonization treatment should be sufficient, at least to ensure that the second carbon source is fully carbonized and the ceramic precursor is sufficiently formed into a ceramic. Therefore, on the basis of the component types in step S011, the ceramic components are uniformly dispersed in the generated carbon coating (i.e., the carbon coating 22 contained in the composite silicon particle 20) by controlling the carbonization temperature, and the generated carbon coating has good mechanical properties and electrolyte isolation properties, so that the prepared composite silicon particle has high specific capacity, a complete carbon coating and good mechanical properties.
In step S02, a mixed material obtained by mixing the composite silicon particles, the conductive agent and the first carbon source in step S01 is a precursor of the above silicon-carbon negative electrode material. In the embodiment, the composite silicon particles, the conductive agent and the first carbon source are mixed according to a mass ratio of 10: (5-20): (85-70) mixing treatment. In a specific embodiment, the mass ratio of the composite silicon particles, the conductive agent and the first carbon source is 10:20: 85. 10:15: 80. 10:5:70, etc. in typical and non-limiting proportions. The mass ratio of the composite silicon particles, the conductive agent and the carbon contained in the generated silicon-carbon negative electrode material is controlled by controlling and optimizing the mixing ratio of the composite silicon particles, the conductive agent and the carbon, so that the charge-discharge efficiency, the charge-discharge rate, the specific capacity and other performances of the prepared silicon-carbon negative electrode material are improved.
Further, before the step of carrying out first carbonization treatment on the mixed material, preparing the mixed material into a mixture dispersion liquid; then carrying out spray drying granulation on the mixture dispersion liquid to obtain mixture particles; the mixture particles are then subjected to a first carbonization treatment. By carrying out spray granulation on the mixed material, on one hand, raw materials of each component can be uniformly mixed, and the particle size of the formed precursor particles is complete and uniform.
The mixed material obtained in the step S02 is a precursor of the silicon-carbon negative electrode material. Thus, the conductive agent is then the conductive agent 30 contained in forming the above silicon carbon anode material. In an embodiment, the first carbon source in step S02 is a precursor for forming carbon 10 contained in the above silicon-carbon negative electrode material, and includes at least one of pitch, biomass carbon, polyethylene glycol, PVP, citric acid, and phenolic resin.
In step S03, after the mixed material obtained in step S02 is subjected to the first carbonization treatment, the first carbon source in the mixed material is cracked to form carbon, that is, carbon 10 contained in the above silicon-carbon negative electrode material, and the material generated after cracking is the above silicon-carbon negative electrode material. In the examples, the temperature of the first carbonization treatment is 600 to 900 ℃, and in the specific examples, the temperature of the first carbonization treatment is 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, and other typical and non-limiting temperatures. The temperature of the first carbonization treatment can be flexibly adjusted and controlled depending on the kind of the first carbon source. In addition, the first carbonization treatment should be sufficient, at least to ensure complete carbonization of the first carbon source, and the temperature of the carbonization treatment should be controlled to improve the electrochemical properties associated with the silicon-carbon anode material.
By the preparation method of the silicon-carbon negative electrode material in each embodiment, the preparation method of the silicon-carbon negative electrode material in the embodiment of the invention can effectively ensure that the composite silicon particles, the conductive agent and the carbon generated by carbonization are uniformly dispersed, thereby ensuring that the carbon, the composite silicon particles and the conductive agent contained in the prepared silicon-carbon negative electrode material play a role in synergism, endowing the prepared silicon-carbon negative electrode material with high charge-discharge efficiency, charge-discharge rate, specific capacity and cycle performance, and simultaneously ensuring that the material particle structure has good mechanical properties. In addition, the preparation method of the silicon-carbon cathode material can ensure that the prepared silicon-carbon cathode material has stable structure and electrochemical performance, is high in efficiency and saves the production cost.
In another aspect, the embodiment of the invention also provides a negative electrode and a lithium ion battery containing the negative electrode.
The negative electrode may be a conventional negative electrode of a lithium ion battery, such as including a current collector and a negative active layer bonded to a surface of the current collector. The negative active layer contains the silicon-carbon negative electrode material disclosed by the invention.
The lithium ion battery provided by the embodiment of the invention comprises the negative electrode. Of course, the lithium ion battery according to the embodiment of the present invention also includes necessary components such as a positive electrode, a separator, and an electrolyte, which are necessary for the lithium ion battery.
Because the lithium ion battery provided by the embodiment of the invention contains the silicon-carbon negative electrode material, the negative electrode has good cycle performance and low internal resistance, so that the lithium ion battery provided by the embodiment of the invention has excellent rate performance and cycle performance, long service life, strong quick charging capability and stable electrochemical performance.
The silicon-carbon anode material, the preparation method and the application thereof according to the embodiments of the present invention are illustrated by a plurality of specific examples.
1. The silicon-carbon negative electrode material and the preparation method thereof are as follows:
example 1
The embodiment provides a silicon-carbon anode material and a preparation method thereof. The silicon-carbon negative electrode material is a granular material shown in fig. 1 and fig. 2, and comprises mixture granules formed by sintering carbon, graphite, composite silicon granules and a CNT conductive agent, wherein the mass ratio of the sintering carbon, the composite silicon granules and the CNT conductive agent is that the composite silicon granules, the conductive agent and asphalt are mixed according to the mass ratio of 10:10:80, and the content of the graphite is 8 percent of the total weight of the silicon-carbon negative electrode material. The composite silicon particles comprise a nano silicon core body with the D90 being less than or equal to 100nm and a carbon coating layer coated on the nano silicon core body and containing alumina, wherein the content of the alumina and the carbon in the carbon coating layer is the content formed by carbonizing aluminum ethoxide.
Through detection, the D90 of the silicon-carbon cathode material is less than or equal to 25 micrometers, and the D90 of the composite silicon particles is less than or equal to 300nm.
The preparation method of the silicon-carbon anode material comprises the following steps:
s1, preparing composite silicon particles: grinding the silicon with the diameter of D90 being less than or equal to 100 mu m in an absolute ethyl alcohol solvent in a sanding mode, adding aluminum ethoxide in the sanding process to coat a carbon coating layer containing aluminum oxide on the surface of the nano silicon powder with the nano micro powder size of D90 being less than or equal to 100nm, and carbonizing at the high temperature of 500 ℃ to obtain nano composite silicon particles;
s2, preparing silicon-carbon secondary particles: uniformly mixing the prepared composite silicon particles, graphite micro powder with the diameter of D90 being less than or equal to 20 microns, asphalt and CNT conductive agent in absolute ethyl alcohol according to a certain proportion (the mass ratio of the composite silicon particles, the CNT conductive agent and the asphalt is 10.
Example 2
The embodiment provides a silicon-carbon negative electrode material and a preparation method thereof. The structure of the silicon carbon negative electrode material was as in example 1. The content of the graphite is 5 percent of the total weight of the silicon-carbon negative electrode material. The composite silicon particles comprise a nano silicon core body with the D90 being less than or equal to 100nm and a carbon coating layer coated on the nano silicon core body and containing alumina, wherein the content of the alumina and the carbon in the carbon coating layer is the content formed by carbonizing aluminum isopropoxide.
Through detection, the D90 of the silicon-carbon negative electrode material is less than or equal to 25 microns, and the D90 of the composite silicon particles is less than or equal to 300nm.
The preparation method of the silicon-carbon anode material comprises the following steps:
s1, preparing composite silicon particles: grinding micron silicon with the D90 being less than or equal to 100 mu m in isopropanol solvent in a sanding mode, adding aluminum isopropoxide in the sanding process, coating a layer of carbon-containing and aluminum-containing material on the surface of nano silicon powder with the nano micro powder size of D90 being less than or equal to 100nm, and carbonizing at the high temperature of 800 ℃ to obtain carbon-coated and aluminum oxide ceramic-coated nano silicon particles;
s2, preparing silicon-carbon secondary particles: the preparation of the prepared composite silicon particles, the graphite micropowder with the diameter of D90 being less than or equal to 300nm, the biomass carbon and the CNT conductive agent are uniformly mixed in absolute ethyl alcohol according to a proportion (the composite silicon particles, the CNT conductive agent and the asphalt are added according to the mass ratio of 10 to 75, and the graphite accounts for 5 percent of the total weight of the silicon carbon negative electrode material), spray granulation is carried out at 500 ℃ by adopting a spray drying mode, and the silicon carbon secondary particles with the D90 being less than or equal to 25 mu m and the three-dimensional conductive network are obtained after high-temperature carbonization at 800 ℃.
Example 3
The embodiment provides a silicon-carbon negative electrode material and a preparation method thereof. The structure of the silicon carbon negative electrode material was as in example 1. The content of the graphite is 10 percent of the total weight of the silicon-carbon negative electrode material. The composite silicon particles comprise a nano silicon core body with the D90 being less than or equal to 100nm and a carbon coating layer coated on the nano silicon core body and containing alumina, wherein the content of the alumina and the carbon in the carbon coating layer is the content formed by carbonizing aluminum alkoxide.
Through detection, the D90 of the silicon-carbon negative electrode material is less than or equal to 25 microns, and the D90 of the composite silicon particles is less than or equal to 300nm.
The preparation method of the silicon-carbon anode material comprises the following steps:
s1, preparing composite silicon particles: the micron silicon with the D90 being less than or equal to 100 mu m is ground in an ethanol solvent in a sanding mode, and aluminum alkoxide is added in the sanding process, so that the nano silicon powder with the nano micro powder size being less than or equal to D90 nm is coated with a layer of carbon-containing and aluminum-containing material on the surface, and then the nano silicon particles coated with carbon and aluminum oxide ceramics are obtained through high-temperature carbonization at the temperature of 600 ℃.
S2, preparing silicon-carbon secondary particles: the preparation of the prepared composite silicon particles, the graphite micro powder with the diameter of D90 being less than or equal to 20 microns, the polyethylene glycol and the CNT conductive agent are uniformly mixed in absolute ethyl alcohol according to a proportion (the composite silicon particles, the CNT conductive agent and the asphalt are added according to the mass ratio of 10 to 85, and the graphite is added according to the proportion that the graphite accounts for 10 percent of the total weight of the silicon-carbon negative electrode material), spray granulation is carried out at 400 ℃ by adopting a spray drying mode, and the silicon-carbon secondary particles with the diameter of D90 being less than or equal to 25 microns and a three-dimensional conductive network are obtained after high-temperature carbonization at 600 ℃.
Example 4
The embodiment provides a silicon-carbon anode material and a preparation method thereof. The structure of the silicon carbon anode material is as in the silicon carbon anode material in example 1. Compared to example 1, no graphite was present.
The preparation method of the silicon-carbon anode material of the embodiment is prepared according to the method in the embodiment 1.
2. The lithium ion battery comprises the following embodiments:
the silicon-carbon negative electrode materials provided in the above examples 1 to 4 and the silicon-carbon negative electrode material provided in the comparative example were assembled into a negative electrode and a lithium ion battery, respectively, as follows:
negative electrode: the silicon-carbon anode materials provided in the above examples 1 to 4 and the silicon-carbon anode material provided in the comparative example were used as anodes, and anodes were prepared as follows;
negative electrode: the silicon-based negative electrode material provided in the above example and the silicon-based negative electrode material provided in the comparative example were used as negative electrode active materials, 96wt% of the silicon-based negative electrode active material, 1wt% of the Super P conductive material, and 1wt% of the carboxymethyl cellulose thickener and 2wt% of the styrene-butadiene rubber binder were mixed in a pure water solvent, and a negative electrode active material slurry was used in a paper cup and a size was coated on a Cu foil current collector, followed by drying, rolling, and cutting to manufacture a negative electrode.
And (3) positive electrode: 96wt% LiCoO 2 The positive electrode active material, 2wt% of Super P conductive material, and 2wt% of PVDF binder were mixed in N-methylpyrrolidone solvent to prepare a positive electrode active material slurry, and the slurry was coated on an Al foil current collector, followed by drying, rolling, and slitting to manufacture a positive electrode.
The positive electrode, the negative electrode and the non-aqueous electrolyte are used to manufacture a rechargeable lithium battery using a general process. As the nonaqueous electrolyte, 1.1MLiPF dissolved therein was used 6 A mixed solvent of ethylene carbonate and diethyl carbonate (containing various additives).
Assembling the lithium ion battery: and assembling the batteries in an inert atmosphere glove box according to the structural assembly sequence of the lithium ion batteries.
3. Correlation characteristic test
Lithium ion battery electrochemical performance test
And (3) carrying out electrochemical lithium intercalation for three times (the charge-discharge multiplying power is 0.05C, and the charge-discharge cutoff voltage is 0.05-1.5V) on the negative electrode in the section 2, assembling the negative electrode into a lithium ion battery, and testing the first charge-discharge efficiency, multiplying power and cycle life of each lithium ion battery. The measured results are shown in the following table 1:
TABLE 1
First charge-discharge efficiency Maximum charge rate 0.5C cycle life
Example 1 92.3％ 2C 955 times
Example 2 90.7％ 2C 976 times
Example 3 91.0％ 2C 943 times
As can be seen from Table 1, the lithium ion battery containing the silicon-carbon negative electrode material provided by the embodiment of the invention has the first charge-discharge efficiency higher than 90%, the maximum charge multiplying factor up to 2C, the 0.5C cycle life up to 955 times, excellent first effect, multiplying factor performance and cycle performance, and good quick charge performance. Therefore, the silicon-carbon negative electrode material disclosed by the embodiment of the invention has the advantages of low resistance, high conductivity, stable particle structure in the charging process, high specific capacity, high charging and discharging efficiency and high charging and discharging rate performance.
The above description is intended to be illustrative of the preferred embodiment of the present invention and should not be taken as limiting the invention, but rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Claims (10)

1. A silicon-carbon negative electrode material is characterized in that: the composite silicon particles comprise a silicon-based core body and a carbon coating layer coating the silicon-based core body, and the carbon coating layer is doped with ceramic.
2. The silicon-carbon anode material according to claim 1, wherein: the mass ratio of the carbon to the composite silicon particles to the conductive agent is that the composite silicon particles, the conductive agent and the first carbon source are mixed according to the mass ratio of 10: (5-20): (85-70) ratio of carbonization treatment after mixing; and/or
The carbon is a carrier, and the composite silicon particles and the conductive agent are dispersed in the carrier; and/or
The particle size of the composite silicon particles is in a nanometer range; and/or
The conductive agent comprises at least one of carbon nano tube, super p, graphene and graphite micro powder; and/or
The carbon is a cracked carbon.
3. The silicon-carbon anode material according to claim 1, wherein: the silicon core body is simple substance silicon; and/or
The ceramic comprises at least one of alumina, silicon carbide and titanium dioxide; and/or
The thickness of the carbon coating layer is 5-8nm.
4. The silicon-carbon anode material according to any one of claims 1 to 3, wherein: the silicon carbon anode material further includes a capacity extender mixed with the carbon, the composite silicon particles, and the conductive agent.
5. The silicon-carbon anode material according to claim 4, wherein: the content of the capacity replenisher in the silicon-carbon negative electrode material is 5% -10%; and/or
The capacity extender includes graphite.
6. A preparation method of a silicon-carbon negative electrode material comprises the following steps:
providing composite silicon particles; the composite silicon particles comprise a silicon-based core body and a carbon coating layer coating the silicon-based core body, and the carbon coating layer is doped with ceramic;
mixing the composite silicon particles with a conductive agent and a first carbon source to obtain a mixed material;
and carrying out first carbonization treatment on the mixed material.
7. The production method according to claim 6, wherein the composite silicon particles, the conductive agent and the first carbon source are mixed in a mass ratio of 10: (5-20): (85-70) carrying out mixing treatment;
and/or
Preparing the mixed material into a mixture dispersion liquid before the step of performing the first carbonization treatment on the mixed material; then carrying out spray drying granulation on the mixture dispersion liquid to obtain mixture particles; then subjecting the mixture particles to the first carbonization treatment;
and/or
The composite silicon particles are prepared by the method comprising the following steps:
mixing silicon-based particles with a second carbon source containing a ceramic precursor to form a coating layer on the surface of the silicon-based particles by the second carbon source containing the ceramic precursor, thereby obtaining a composite silicon particle precursor;
and carrying out second carbonization treatment on the composite silicon particle precursor to obtain the composite silicon particles.
8. The method according to claim 7, wherein the silicon-based particles comprise at least one of elemental silicon, silicon carbide, and silicon monoxide; and/or
The second carbon source comprises at least one of an organic aluminum source and an organic titanium source; and/or
The temperature of the second carbonization treatment is 600-900 ℃.
9. The production method according to any one of claims 6 to 8, wherein the first carbon source includes at least one of pitch, biomass charcoal, polyethylene glycol, PVP, citric acid, and phenol resin; and/or
The temperature of the first carbonization treatment is 600-900 ℃.
10. A lithium ion battery comprises a negative electrode, wherein the negative electrode comprises a current collector and a negative active layer combined on the surface of the current collector, and is characterized in that: the negative electrode active layer contains the silicon-carbon negative electrode material according to any one of claims 1 to 5 or the silicon-carbon negative electrode material prepared by the preparation method according to any one of claims 6 to 9.
CN202110637574.XA 2021-06-08 2021-06-08 Silicon-carbon negative electrode material, preparation method thereof and lithium ion battery Pending CN115458715A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116854094A (en) * 2023-09-04 2023-10-10 琥崧智能装备(太仓)有限公司 Carbon-silicon negative electrode active material, and preparation method and application thereof
CN117594779A (en) * 2024-01-19 2024-02-23 湖南镕锂新材料科技有限公司 Carbon-silicon composite material and application thereof in lithium battery

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116854094A (en) * 2023-09-04 2023-10-10 琥崧智能装备(太仓)有限公司 Carbon-silicon negative electrode active material, and preparation method and application thereof
CN116854094B (en) * 2023-09-04 2023-12-05 琥崧智能装备(太仓)有限公司 Carbon-silicon negative electrode active material, and preparation method and application thereof
CN117594779A (en) * 2024-01-19 2024-02-23 湖南镕锂新材料科技有限公司 Carbon-silicon composite material and application thereof in lithium battery
CN117594779B (en) * 2024-01-19 2024-03-29 湖南镕锂新材料科技有限公司 Carbon-silicon composite material and application thereof in lithium battery

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