Silicon-carbon negative electrode material, preparation method and application in lithium ion battery

Abstract

This invention relates to a silicon-carbon anode material, its preparation method, and its application in lithium-ion batteries. The silicon-carbon anode material comprises an elastic cage-like carbon material core with deposited nano-silicon particles and a disordered carbon layer shell. The carbon material framework of the elastic cage-like carbon material core specifically includes fullerene C. 60 C 70 Or C 80 One of the formed spherical carbon molecular core structures has nano-silicon particles embedded in it; disordered carbon atoms surround the core to form a disordered carbon layer shell; the average thickness of the disordered carbon layer shell is not less than 10 nm.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery anode material technology, and in particular to a silicon-carbon anode material, its preparation method, and its application in lithium-ion batteries. Background Technology

[0002] Lithium-ion batteries have attracted much attention due to their high energy density, lack of memory effect, and ability to be used multiple times by charging and discharging. Among them, the anode material is a crucial component of lithium-ion batteries, and the development of new high-capacity, long-cycle-life lithium-ion battery anode materials is urgently needed.

[0003] Carbon materials have been extensively studied as anode materials for lithium-ion batteries, especially graphite anode materials, which are favored by the industry due to their good conductivity and stable cycle life. However, the theoretical specific capacity of graphite anode is only 372 mAh / g, which severely limits the energy density of lithium-ion batteries.

[0004] Silicon, as an element in the same group as carbon, has attracted attention as a negative electrode material for lithium-ion batteries due to its extremely high theoretical specific capacity (4200 mAh / g). Furthermore, silicon is abundant on Earth and holds promise for gradually replacing graphite as the mainstream material in lithium-ion batteries. However, silicon materials expand in volume during charging and discharging due to alloy formation, which significantly limits their large-scale production and application in lithium-ion batteries.

[0005] Therefore, there is an urgent need to develop a silicon-carbon composite anode material with low expansion, high capacity, and high initial efficiency to solve the problem of silicon volume expansion during lithium-ion charging and discharging, thereby improving the cycle life of lithium-ion batteries. Summary of the Invention

[0006] The purpose of this invention is to provide a silicon-carbon anode material, its preparation method, and its application in lithium-ion batteries. By depositing an elastic cage-like carbon material core with nano-silicon particles and a disordered carbon layer shell, the volume expansion of silicon during charging and discharging can be effectively suppressed, further improving the cycle stability of lithium-ion batteries. This allows the low-expansion silicon-carbon anode material to exhibit a higher specific capacity, which is beneficial for improving the energy density of lithium-ion batteries.

[0007] Therefore, in a first aspect, embodiments of the present invention provide a silicon-carbon anode material, which is composed of an elastic cage-like carbon material core with deposited nano-silicon particles and a disordered carbon layer shell.

[0008] The carbon material framework of the elastic cage-like carbon material core specifically includes fullerene C. 60 C 70 Or C 80One of the formed spherical carbon molecular core structures has nano-silicon particles embedded in it; disordered carbon atoms surround the core to form a disordered carbon layer shell; the average thickness of the disordered carbon layer shell is not less than 10 nm.

[0009] In a second aspect, embodiments of the present invention provide a method for preparing the silicon-carbon anode material described in the first aspect above, the method comprising: performing high-temperature vapor deposition and high-temperature vapor coating sequentially under an inert atmosphere;

[0010] The high-temperature vapor deposition process includes: placing the carbon material skeleton raw material in a high-temperature furnace, introducing silicon source gas to deposit nano-silicon particles in the carbon material skeleton, and obtaining an elastic cage-like carbon material core with deposited nano-silicon particles.

[0011] The high-temperature gas phase coating process includes: shutting off the silicon source gas, introducing a carbon source gas, and coating the surface of the elastic cage-like carbon material core with deposited nano-silicon particles to form a disordered carbon layer shell.

[0012] Preferably, the silicon source gas used in the high-temperature vapor deposition process is silane and / or silane; the temperature of the high-temperature vapor deposition is 400℃-1000℃, and the time of the high-temperature vapor deposition is 2h-10h.

[0013] Preferably, the carbon source gas used in the high-temperature gas phase coating process is one or more of acetylene, ethylene, or propylene; the temperature of the high-temperature gas phase coating is 400℃-1000℃, and the time of the high-temperature gas phase coating is 2h-10h.

[0014] Preferably, the carbon material framework raw material includes fullerene C. 60 C 70 Or C 80 The specific process of introducing silicon source gas to deposit nano-silicon particles into the carbon material framework is as follows:

[0015] By introducing a silicon source gas, nano-silicon particles are deposited on fullerene C. 60 C 70 Or C 80 In the cage-like structure.

[0016] Thirdly, embodiments of the present invention provide a lithium-ion battery, the lithium-ion battery comprising the silicon-carbon anode material described in the first aspect above.

[0017] Preferably, during the charging process of the lithium-ion battery, the silicon-carbon anode material is lithium-intercalated, and the nano-silicon particles in the silicon-carbon anode material are lithium-intercalated to form a silicon-lithium alloy; during the discharging process of the lithium-ion battery, the silicon-carbon anode material is delithiated, and the silicon-lithium alloy is delithiated and reduced to nano-silicon particles.

[0018] The silicon-carbon anode material provided in this invention, through its core structure of embedded nano-silicon particles within an elastic cage-like carbon material, helps improve the specific capacity of the battery. This structure contributes to higher energy storage capacity and enhances the energy density of lithium-ion batteries. The silicon-carbon anode material, employing an elastic cage-like carbon core and a disordered carbon layer shell, effectively suppresses silicon volume expansion, achieving low expansion and thus improving the cycle stability of lithium-ion batteries. Due to its high specific capacity and ability to suppress silicon volume expansion, this material significantly improves the performance of lithium-ion batteries, making them more stable during charge and discharge processes and extending battery life. The silicon-carbon anode material provided by this invention has promising application prospects. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the preparation method of silicon-carbon anode material provided in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the structure of the silicon-carbon anode material provided in an embodiment of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0022] This invention provides a silicon-carbon anode material, which consists of an elastic cage-like carbon material core with deposited nano-silicon particles and a disordered carbon layer shell.

[0023] The carbon material framework of the elastic cage-like carbon material core specifically includes fullerene C. 60 C 70 Or C 80 One of the formations is a spherical carbon molecule core structure, in which nano-silicon particles are embedded;

[0024] The disordered carbon atoms surround the core to form a disordered carbon shell; the disordered carbon atoms in the disordered carbon shell form a thick coating with an average thickness of not less than 10 nm. The preferred coating thickness is 10 nm to 20 nm.

[0025] The silicon-carbon anode material of this invention is obtained by sequentially performing high-temperature vapor deposition and high-temperature vapor coating on carbon material framework raw materials under an inert atmosphere. The main method steps are as follows: Figure 1 As shown. The main steps include:

[0026] Step 110: Place the carbon material skeleton raw material in a high-temperature furnace, introduce silicon source gas to deposit nano-silicon particles in the carbon material skeleton, and obtain an elastic cage-like carbon material core with deposited nano-silicon particles.

[0027] Carbon material framework raw materials include fullerene (C).60 C 70 Or C 80 Fullerenes have a cage-like (also called spherical) structure, with C1 as the main component. 60 For example, a fullerene consists of 60 carbon atoms, each connected to its neighboring carbon atoms by carbon-carbon bonds, forming a spherical structure similar to a soccer ball. These carbon atoms are arranged in hexagonal and pentagonal shapes, linked together by carbon-carbon bonds, forming a highly symmetrical and stable fullerene molecular structure. Fullerene C 60 C 70 Or C 80 It has a certain degree of elasticity. Although it is a substructure composed of carbon atoms, at the microscopic scale, due to the flexibility of its molecular structure and the elastic properties of carbon-carbon bonds, it still has some elasticity to a certain extent.

[0028] The carbon source gas used in the high-temperature gas phase coating process is one or more of acetylene, ethylene or propylene; the temperature of the high-temperature gas phase coating is 400℃-1000℃, and the time of the high-temperature gas phase coating is 2h-10h.

[0029] The high-temperature vapor phase coating process involves depositing nano-silicon particles onto fullerene C by introducing a silicon source gas. 60 C 70 Or C 80 In the cage-like structure.

[0030] Step 120: Turn off the silicon source gas and introduce the carbon source gas to coat the surface of the elastic cage-like carbon material core with deposited nano-silicon particles, forming a disordered carbon layer shell.

[0031] The carbon source gas used in the high-temperature gas phase coating process is one or more of acetylene, ethylene or propylene; the temperature of the high-temperature gas phase coating is 400℃-1000℃, and the time of the high-temperature gas phase coating is 2h-10h.

[0032] The silicon-carbon anode material prepared by this invention is used in lithium-ion batteries. During the charging process of the lithium-ion battery, lithium is intercalated into the silicon-carbon anode material, and the nano-silicon particles in the silicon-carbon anode material form a silicon-lithium alloy. During the discharging process of the lithium-ion battery, lithium is delithilated into the silicon-carbon anode material, and the silicon-lithium alloy is reduced back to nano-silicon particles. (The last sentence appears to be incomplete and possibly refers to a different process.) 60 The specific process of creating a carbon material framework is illustrated as follows: Figure 2 As shown.

[0033] The silicon-carbon anode material provided in this invention, through the embedding of nano-silicon particles within a core structure of an elastic cage-like carbon material, helps improve the specific capacity of the battery. This structure contributes to higher energy storage capacity and enhances the energy density of lithium-ion batteries. The silicon-carbon anode material, employing a core of elastic cage-like carbon material and a disordered carbon layer shell, effectively suppresses silicon volume expansion, thereby improving the cycle stability of lithium-ion batteries. Due to its high specific capacity and ability to suppress silicon volume expansion, this material significantly improves the performance of lithium-ion batteries, making them more stable during charge and discharge processes and extending battery life. The low-expansion silicon-carbon anode material provided by this invention has promising application prospects.

[0034] To more clearly illustrate the purpose and advantages of the present invention, the following description, in conjunction with embodiments, further elaborates on the invention. Furthermore, the embodiments described herein are only some examples; all other embodiments obtained by those skilled in the art based on the embodiments described herein without inventive effort are within the scope of protection of the present invention. Additionally, it should be understood that these embodiments are merely for more detailed explanation and should not be construed as limiting the invention in any way, i.e., they are not intended to limit the scope of protection of the present invention.

[0035] Example 1

[0036] This embodiment provides a method for preparing a low-expansion silicon-carbon anode material.

[0037] Step 1, High-Temperature Vapor Deposition: Add 5 kg of C to the deposition furnace. 60 Carbon-based raw materials were used. Nitrogen gas was introduced at a flow rate of 30 L / min to purge the furnace and create an inert protective atmosphere. After 30 hours of purging, the temperature was increased to 600°C at a rate of 3°C / min and held for 30 minutes to stabilize the furnace temperature. Then, silane was introduced while nitrogen was continuously introduced, maintaining a silane-nitrogen gas flow rate ratio of 20 L / min:30 L / min. The holding time was 5 hours. During this process, the silane underwent decomposition, breaking the SiH bonds and releasing hydrogen and silicon atoms. The resulting nano-silicon particles were deposited on the C substrate. 60 Within the carbon material framework, an elastic cage-like carbon material core with deposited nano-silicon particles is obtained.

[0038] Step 2, High-temperature vapor phase coating: The C nano-silicon deposited on the substrate is coated with the substrate... 60 The conductive carbon substrate remained in the deposition furnace. The silane was shut off, and propylene was introduced. The nitrogen flow rate was adjusted to a nitrogen-to-propylene flow rate ratio of 8 L / min:8 L / min. The holding temperature was 600℃ for 8 hours. Propylene decomposed, depositing nano-silicon onto the C substrate. 60A disordered carbon layer shell is formed on the surface of a conductive carbon substrate to obtain a low-expansion silicon-carbon anode material.

[0039] Anode sheets were prepared using low-expansion silicon-carbon anode material obtained in a deposition furnace, and coin-type half-cells were assembled and tested, as detailed below:

[0040] The obtained low-expansion silicon-carbon anode material, conductive agent Super P, and binder carboxymethyl cellulose (CMC) were thoroughly ground in a mortar at a mass ratio of 8:1:1. Deionized water was then added to form a slurry, which was coated onto a copper foil current collector and dried in a vacuum oven at 80°C for 12 hours. The dried electrode was then cut into 12mm diameter discs to serve as the anode plates for lithium-ion batteries.

[0041] The counter electrode of the coin cell was a lithium sheet, and the electrolyte used was an aqueous electrolyte, specifically 1M LiPF6@ethylene carbonate (EC) / dimethyl carbonate (DMC) / diethyl carbonate (DEC) with a volume ratio v / v / v = 1:1:1. The coin cells were assembled in a glove box. Finally, the electrochemical performance was evaluated using a Blue Battery testing system. The half-cell was tested in constant current charge-discharge mode, with a discharge cutoff voltage of 0.005V and a charge cutoff voltage of 2V. The capacity retention and initial coulombic efficiency after 500 cycles at 0.5C are shown in Table 1.

[0042] Example 2

[0043] Step 1, High-Temperature Vapor Deposition: Add 5 kg of C to the deposition furnace. 70 Carbon-based raw materials were used. Nitrogen gas was introduced at a flow rate of 30 L / min to purge the furnace and create an inert protective atmosphere. After 30 hours of purging, the temperature was increased to 600°C at a rate of 3°C / min and held for 30 minutes to stabilize the furnace temperature. Then, silane was introduced while nitrogen was continuously introduced, maintaining a silane-nitrogen gas flow rate ratio of 20 L / min:30 L / min. The holding time was 5 hours. During this process, the silane underwent decomposition, breaking the SiH bonds and releasing hydrogen and silicon atoms. The resulting nano-silicon particles were deposited on the C substrate. 70 Within the carbon material framework, an elastic cage-like carbon material core with deposited nano-silicon particles is obtained.

[0044] Step 2, High-temperature vapor phase coating: The C nano-silicon deposited on the substrate is coated with the substrate... 70 The conductive carbon substrate remained in the deposition furnace. The silane was shut off, and propylene was introduced. The nitrogen flow rate was adjusted to a nitrogen-to-propylene flow rate ratio of 8 L / min:8 L / min. The holding temperature was 600℃ for 8 hours. Propylene decomposed, depositing nano-silicon onto the C substrate. 70A disordered carbon layer shell is formed on the surface of a conductive carbon substrate to obtain a low-expansion silicon-carbon anode material.

[0045] Anode sheets were prepared using the low-expansion silicon-carbon anode material obtained in the deposition furnace, and coin cells were assembled for testing, using the same method as in Example 1. Test data are shown in Table 1.

[0046] Example 3

[0047] Step 1, High-Temperature Vapor Deposition: Add 5 kg of C to the deposition furnace. 80 Carbon-based raw materials were used. Nitrogen gas was introduced at a flow rate of 30 L / min to purge the furnace and create an inert protective atmosphere. After 30 hours of purging, the temperature was increased to 600°C at a rate of 3°C / min and held for 30 minutes to stabilize the furnace temperature. Then, silane was introduced while nitrogen was continuously introduced, maintaining a silane-nitrogen gas flow rate ratio of 20 L / min:30 L / min. The holding time was 5 hours. During this process, the silane underwent decomposition, breaking the SiH bonds and releasing hydrogen and silicon atoms. The resulting nano-silicon particles were deposited on the C substrate. 80 Within the carbon material framework, an elastic cage-like carbon material core with deposited nano-silicon particles is obtained.

[0048] Step 2, High-temperature vapor phase coating: The C nano-silicon deposited on the substrate is coated with the substrate... 80 The conductive carbon substrate remained in the deposition furnace. The silane was shut off, and propylene was introduced. The nitrogen flow rate was adjusted to a nitrogen-to-propylene flow rate ratio of 8 L / min:8 L / min. The holding temperature was 600℃ for 8 hours. Propylene decomposed, depositing nano-silicon onto the C substrate. 80 A disordered carbon layer shell is formed on the surface of a conductive carbon substrate to obtain a low-expansion silicon-carbon anode material.

[0049] Anode sheets were prepared using the low-expansion silicon-carbon anode material obtained in the deposition furnace, and coin cells were assembled for testing, using the same method as in Example 1. Test data are shown in Table 1.

[0050] Example 4

[0051] Step 1, High-Temperature Vapor Deposition: Add 5 kg of C to the deposition furnace. 60 Carbon-based raw materials were used. Nitrogen gas was introduced at a flow rate of 20 L / min to purge the furnace and create an inert protective atmosphere. After 30 hours of purging, the temperature was increased to 900°C at a rate of 5°C / min and held for 30 minutes to stabilize the furnace temperature. Then, silane was introduced while nitrogen was continuously introduced, maintaining a silane:nitrogen gas flow rate ratio of 20 L / min:20 L / min. The holding time was 5 hours. During this process, the silane underwent decomposition, breaking the SiH bonds and releasing hydrogen and silicon atoms. The resulting nano-silicon particles were deposited on the C substrate.60 Within the carbon material framework, an elastic cage-like carbon material core with deposited nano-silicon particles is obtained.

[0052] Step 2, High-temperature vapor phase coating: The C nano-silicon deposited on the substrate is coated with the substrate... 60 The conductive carbon substrate remained in the deposition furnace. The silane was shut off, and acetylene was introduced. The nitrogen flow rate was adjusted to a nitrogen-to-acetylene flow rate ratio of 10 L / min:8 L / min. The holding temperature was 900℃ for 4 hours. The acetylene decomposed, depositing nano-silicon onto the C substrate. 60 A disordered carbon layer shell is formed on the surface of a conductive carbon substrate to obtain a low-expansion silicon-carbon anode material.

[0053] Example 5

[0054] Step 1, High-Temperature Vapor Deposition: Add 5 kg of C to the deposition furnace. 60 Carbon-based raw materials were used. Nitrogen gas was introduced at a flow rate of 20 L / min to purge the furnace and create an inert protective atmosphere. After 30 hours of purging, the temperature was increased to 800°C at a rate of 5°C / min and held for 30 minutes to stabilize the furnace temperature. Then, silane was introduced while nitrogen was continuously introduced, maintaining a silane:nitrogen gas flow rate ratio of 20 L / min:20 L / min. The holding time was 5 hours. During this process, the silane underwent decomposition, breaking the SiH bonds and releasing hydrogen and silicon atoms. The resulting nano-silicon particles were deposited on the C substrate. 60 Within the carbon material framework, an elastic cage-like carbon material core with deposited nano-silicon particles is obtained.

[0055] Step 2, High-temperature vapor phase coating: The C nano-silicon deposited on the substrate is coated with the substrate... 60 The conductive carbon substrate was kept in the deposition furnace, the silane was turned off, and the temperature was lowered to 600℃. It was held for 15 minutes, then ethylene was introduced. The nitrogen flow rate was adjusted to a nitrogen-to-ethylene flow rate ratio of 8 L / min:8 L / min. The holding temperature was 600℃ for 6 hours. Ethylene decomposed, and the carbon substrate was deposited with nano-silicon. 60 A disordered carbon layer shell is formed on the surface of a conductive carbon substrate to obtain a low-expansion silicon-carbon anode material.

[0056] Comparative Example 1

[0057] Step 1: 5 kg of conductive carbon black is added to the deposition furnace as the carbon substrate raw material, and nitrogen gas is introduced at a flow rate of 30 L / min to form a protective atmosphere. After half an hour of gas introduction, the temperature is raised to 600°C at a heating rate of 3°C / min and then maintained at the temperature for 30 min. Then, silane and nitrogen gas are introduced at a gas flow rate ratio of 20 L / min: 30 L / min, and the holding time is 5 h.

[0058] Step 2: The conductive carbon black substrate with deposited silicon is placed back into the deposition furnace. The silane is shut off, propylene is introduced, and the nitrogen flow rate is adjusted to a nitrogen to propylene flow rate ratio of 8 L / min:8 L / min. The holding temperature is 600℃, and the holding time is 8 hours. The negative electrode active material is obtained.

[0059] The active material obtained in the deposition furnace was used as the negative electrode material for lithium-ion batteries to assemble coin cells for testing, using the same method as in Example 1. The test data are shown in Table 1.

[0060] Comparative Example 2

[0061] Step 1: 5 kg of carbon nanotubes are added to the deposition furnace as carbon substrate raw material, and nitrogen gas is introduced at a flow rate of 30 L / min to form a protective atmosphere. After half an hour of gas introduction, the temperature is raised to 600°C at a heating rate of 3°C / min and then held for 30 min. Then, silane and nitrogen gas are introduced at a gas flow rate ratio of 20 L / min: 30 L / min, and the holding time is 5 h.

[0062] Step 2: The conductive carbon black substrate with deposited silicon is placed back into the deposition furnace. The silane is shut off, propylene is introduced, and the nitrogen flow rate is adjusted to a nitrogen to propylene flow rate ratio of 8 L / min:8 L / min. The holding temperature is 600℃, and the holding time is 8 hours. The negative electrode active material is obtained.

[0063] The active material obtained in the deposition furnace was used as the negative electrode material for lithium-ion batteries to assemble coin cells for testing, using the same method as in Example 1. The test data are shown in Table 1.

[0064] Table 1 shows the comparison data of capacity retention and initial coulombic efficiency of lithium-ion coin cells prepared in Examples 1-3 and Comparative Examples 1-2 after 500 cycles at 0.5C rate.

[0065] Cycle retention rate 95.5％ 90.1％ 92.4％ 33.3％ 45.0％ First Coulomb efficiency 92.6％ 91.8％ 92.1％ 88.0％ 83.5％

[0066] Table 1

[0067] The comparison of capacity retention and initial coulombic efficiency of the lithium-ion coin cells prepared in the examples and comparative examples in Table 1 after 500 cycles at 0.5C rate shows that the silicon-carbon active materials in Examples 1-3, prepared through a one-step high-temperature vapor deposition and high-temperature vapor coating method, exhibit significantly better cycle stability than the silicon-carbon anode materials in Comparative Examples 1-2 when used as the negative electrode material for lithium-ion half-cells. Furthermore, the initial coulombic efficiency in Examples 1-3 is higher than that in Comparative Examples 1-2. This demonstrates that by selecting a cage-like conductive carbon substrate as the substrate for depositing nano-silicon, the volume expansion of silicon during charge and discharge can be effectively mitigated, thereby greatly improving the cycle stability and initial coulombic efficiency of lithium-ion batteries.

[0068] This invention provides a method for preparing silicon-carbon anode materials, selecting C... 60 C 70 and C 80 The core conductive substrate, represented by silicon nanoparticles, is deposited into the interior of an elastic cage-like substrate using a high-temperature vapor deposition method. This provides sufficient space for the volume expansion of silicon after alloying, effectively solving the problem of volume expansion of silicon during charging and discharging. Furthermore, by coating the cage-like substrate with a thicker disordered carbon shell, the cage-like substrate with deposited silicon nanoparticles can be closed, improving its first coulombic efficiency.

[0069] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A silicon-carbon negative electrode material, characterized in that, The silicon-carbon anode material consists of an elastic cage-like carbon material core with deposited nano-silicon particles and a disordered carbon layer shell. The carbon material framework of the elastic cage-like carbon material core specifically includes fullerene C. 60 C 70 Or C 80 One of the formed spherical carbon molecule core structures, wherein the nano-silicon particles are embedded in the core structure; The disordered carbon atoms wrap around the core to form the disordered carbon shell, which makes the elastic cage-like carbon material core complete the pore closure; the average thickness of the disordered carbon shell is 10nm-20nm.

2. A method of producing the silicon-carbon negative electrode material according to claim 1, characterized in that The preparation method includes: performing high-temperature vapor deposition and high-temperature vapor coating successively under an inert atmosphere; The high-temperature vapor deposition process includes: placing the carbon material skeleton raw material in a high-temperature furnace, introducing silicon source gas to deposit nano-silicon particles in the carbon material skeleton, and obtaining an elastic cage-like carbon material core with deposited nano-silicon particles. The high-temperature gas phase coating process includes: shutting off the silicon source gas, introducing a carbon source gas, and coating the surface of the elastic cage-like carbon material core with deposited nano-silicon particles to form a disordered carbon layer shell with an average thickness of 10nm-20nm, so that the elastic cage-like carbon material core completes the pore closing. The carbon material skeleton raw material includes fullerene C 60 , C 70 or C 80 The silicon source gas is introduced to deposit nano-silicon particles in the carbon material skeleton. The silicon nanoparticles are deposited in the cage structure of fullerene C 60 , C 70 or C 80 by introducing a silicon source gas.

3. The preparation method according to claim 2, characterized in that, The silicon source gas used in the high-temperature vapor deposition process is silane and / or silane; the temperature of the high-temperature vapor deposition is 400℃-1000℃, and the time of the high-temperature vapor deposition is 2h-10h.

4. The preparation method according to claim 2, characterized in that, The carbon source gas used in the high-temperature gas phase coating process is one or more of acetylene, ethylene or propylene; the temperature of the high-temperature gas phase coating is 400℃-1000℃, and the time of the high-temperature gas phase coating is 2h-10h.

5. A lithium-ion battery, characterized by The lithium-ion battery includes the silicon-carbon anode material as described in claim 1.

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