Carbon-silicon material, method of making and use thereof

Abstract

The application provides a silicon-carbon material, a preparation method and application thereof, the silicon-carbon material comprises a carbon skeleton and elemental silicon deposited on the carbon skeleton; the Raman spectrum of the silicon-carbon material has D peaks and G peaks in the wave number range of 1350cm ‑1 -1650cm ‑1 , and ID / IG is 1.0-1.5; the spectrum peak of the elemental silicon has a wave number in the range of 460cm ‑1 -480cm ‑1 . The silicon-carbon material provided by the application is a structure in which elemental silicon is deposited on a carbon skeleton, the thickness of the thin-film silicon in the Z-axis direction is far less than the critical size of 150nm, the silicon can resist the stress caused by volume expansion through its Young's modulus, the volume expansion rate of the silicon can be effectively inhibited, and the full-electricity expansion rate of the obtained silicon-carbon material is less than 30%.

Description

Technical Field

[0001] This invention relates to silicon carbide materials, their preparation methods, and applications. Background Technology

[0002] In today's rapidly developing new energy industry, improving the specific capacity of anode materials is of great significance for increasing the energy density of lithium batteries. Currently, the mainstream commercial anode material is graphite-based, with a specific capacity that has reached the theoretical upper limit of 372 mAh / g. In contrast, silicon materials, which belong to the same group, have a theoretical specific capacity as high as 4200 mAh / g, making them the anode material with the highest known specific capacity and extremely promising application prospects and market value.

[0003] However, silicon anodes experience severe volume deformation during charging and discharging, with an expansion rate as high as 300%, directly leading to structural damage and mechanical breakage of the battery electrode, severely limiting their commercial application. To address these issues, silicon nanostructuring and compounding with graphite-based materials are two mainstream approaches. Graphene, as a "star material," has been widely introduced into silicon-carbon anode systems in recent years, significantly buffering the volume expansion of silicon and improving the material's cycle performance.

[0004] CN106941169B reports a porous graphene / silicon composite anode material. By introducing flexible graphene, the material's conductivity and cycle stability are improved, while the obstruction of ion transport by the planar two-dimensional structure of the graphite sheets is minimized. However, this process still requires subsequent spray granulation using pitch and graphite, and the initial coulombic efficiency and electrode full-charge expansion rate of the product are not reported.

[0005] CN111498829B reports a graphene-based silicon-carbon anode material, which is prepared by electrostatic adsorption between a gel coating layer and graphene oxide. However, the specific capacity of the material is relatively low (<700 mAh / g), making it difficult to meet the future demand for high-capacity silicon-carbon anodes. Summary of the Invention

[0006] The purpose of this invention is to overcome the technical defects of existing silicon-carbon materials and to provide a new type of silicon-carbon material with advantages such as high specific capacity, small volume expansion, and long cycle life.

[0007] According to a first aspect of the present invention, a silicon-carbon material is provided, comprising a carbon framework and elemental silicon deposited on the carbon framework; the Raman spectrum of the silicon-carbon material is at a wavenumber of 1350 cm⁻¹. -1 -1650cm -1 It exhibits both D and G peaks within the range, and the ID / IG ratio is 1.0–1.5; at 460 cm⁻¹ -1 -480cm -1 It contains spectral peaks of elemental silicon within the range.

[0008] According to a second aspect of the present invention, the present invention provides a method for preparing the silicon-carbon material of the present invention, the method comprising the following steps:

[0009] Silicon was deposited on a carbon framework material using vapor deposition; the Raman spectrum of the carbon framework material was observed at a wavenumber of 1350 cm⁻¹. -1 -1650cm -1 It exhibits both D and G peaks within the range, with an ID / IG ratio of 1.0–1.5 and a specific surface area of ​​300–500 m². 2 / g.

[0010] According to a third aspect of the present invention, the present invention provides the application of the silicon-carbon material described herein as a battery anode material; preferably, its application as a lithium battery anode material.

[0011] Compared with the prior art, the superior effects of the present invention are as follows:

[0012] 1) The silicon-carbon material provided by this invention is a silicon-deposited carbon skeleton structure, which can resist the stress caused by volume expansion through its own Young's modulus, and can effectively suppress the volume expansion rate of silicon. The full charge expansion rate of the obtained silicon-carbon material is <30%.

[0013] 2) In the silicon-carbon material provided by the present invention, carbon is the framework structure and silicon is deposited on its surface by vapor deposition, which avoids the problem of carbon and silicon dispersion in traditional processes, solves the problem of lithium ion transport obstruction caused by carbon materials, and avoids excessive local expansion caused by uneven dispersion of silicon on the surface of carbon materials.

[0014] 3) The silicon-carbon material provided by the present invention avoids the processing difficulties caused by the large specific surface area of ​​traditional composite materials based on porous carbon due to the use of vapor deposition process. Attached Figure Description

[0015] Figure 1 SEM image of the silicon-carbon anode obtained in Example 1;

[0016] Figure 2 These are TEM and HRTEM images of the silicon-carbon anode obtained in Example 1;

[0017] Figure 3 The BET curve of the silicon-carbon anode obtained in Example 1;

[0018] Figure 4 The image shows the Raman spectrum of the silicon-carbon anode obtained in Example 1. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] This invention provides a silicon-carbon material comprising a carbon framework and elemental silicon deposited on the carbon framework; the Raman spectrum of the silicon-carbon material is at a wavenumber of 1350 cm⁻¹. -1 -1650cm -1 It exhibits both D and G peaks within the range, and the ID / IG ratio is 1.0–1.5; at 460 cm⁻¹ -1 -480cm -1 The spectrum contains spectral peaks characteristic of elemental silicon. Silicon-carbon materials possessing the aforementioned structural features of this invention have the advantages of low volume expansion at full charge and low silicon loading for the same specific capacity.

[0021] According to a preferred embodiment of the present invention, the specific capacity of the silicon-carbon material is ≥1500 mAh g. -1 Further optimization of ≥1800mAh g -1 The initial coulombic efficiency is ≥85%. This demonstrates that the silicon-carbon material of the present invention has the advantages of high initial efficiency and high specific capacity.

[0022] In this invention, there are no special requirements for the composition of the silicon-carbon material, and its composition content can be selected from a wide range. According to a preferred embodiment of the present invention, based on the silicon-carbon material, the mass percentage content of the carbon skeleton is 30wt% to 70wt%, preferably 40wt% to 60wt%; the mass percentage content of elemental silicon is 30wt% to 70wt%, preferably 40wt% to 60wt%.

[0023] According to a preferred embodiment of the present invention, the tap density of the silicon-carbon material is 0.6 g / cm³. 3 ~1.0g / cm 3 0.8g / cm 3 ~0.9g / cm 3 This demonstrates that the silicon-carbon material of the present invention has the advantage of higher bulk density.

[0024] According to a preferred embodiment of the present invention, the particle size D10 of the silicon-carbon material is 1 μm to 3 μm, D50 is 5 μm to 8 μm, and D90 is 12 μm to 16 μm. This demonstrates that the silicon-carbon material of the present invention has the advantages of a narrower particle size distribution and a higher compaction density.

[0025] According to a preferred embodiment of the present invention, the elemental silicon in the silicon-carbon material is deposited on the carbon framework in the form of a thin film or a bulk; this demonstrates that the silicon-carbon material of the present invention has the advantages of smaller volume expansion rate and better cycle stability.

[0026] According to a preferred embodiment of the present invention, the specific surface area of ​​the silicon-carbon material is 1 m². 2 / g~5m 2 / g, pore volume 0.3cm 3 / g~1.2cm 3 / g; This demonstrates that the silicon-carbon material of the present invention has the advantages of lower liquid absorption rate and superior processing performance.

[0027] According to a preferred embodiment of the present invention, the specific capacity of the blend of silicon-carbon material and graphite is greater than or equal to 600 mAh g. -1 The volume expansion rate under full charge is ≤30%. This demonstrates that the silicon-carbon material of the present invention has the advantage of a lower volume expansion rate for the same specific capacity.

[0028] Silicon-carbon materials possessing the aforementioned features of this invention can achieve the objectives of this invention. There are no special requirements regarding their source and preparation method. The following is an illustrative description of a preparation method, but it should not be construed as limiting the invention to the following method only.

[0029] According to one embodiment of the present invention, the method for preparing the silicon-carbon material includes the following steps:

[0030] Silicon was deposited on a carbon framework material using vapor deposition; the Raman spectrum of the carbon framework material was observed at a wavenumber of 1350 cm⁻¹. -1 -1650cm -1 It exhibits both D and G peaks within the range, with an ID / IG ratio of 1.0–1.5 and a specific surface area of ​​300–500 m². 2 / g.

[0031] According to one embodiment of the present invention, preferably, the surface of the product obtained after depositing elemental silicon is coated with carbon.

[0032] In this invention, there are no special requirements for the conditions of vapor deposition, etc. The following is an illustrative description, but it does not limit the scope of the invention.

[0033] According to one embodiment of the present invention, the temperature of vapor deposition is 800°C to 1200°C.

[0034] According to one embodiment of the present invention, the vapor deposition time is 2h to 8h.

[0035] In this invention, a wide range of silicon sources can be selected for deposition. The following is an illustrative example, but it does not limit the scope of this invention.

[0036] According to one embodiment of the present invention, the silicon source is silane, preferably silane, silane, or chlorosilane, and more preferably one or more of silane, silicon tetrachloride, and silicon trichloride.

[0037] In this invention, a carrier may be added as needed. For example, when using silicon trichloride, hydrogen is used as a carrier gas to provide a reducing atmosphere. Alternatively, an inert gas may be added as a carrier depending on the actual operation.

[0038] In this invention, the amount of silicon source used is selected according to the actual need for elemental silicon, which will not be repeated here.

[0039] Carbon framework materials possessing the aforementioned features of this invention can achieve the objectives of this invention. There are no special requirements regarding their source and preparation method. The following is an illustrative description of a preparation method, but it should not be construed as limiting the invention to the following method only.

[0040] According to one embodiment of the present invention, the preparation method of the carbon framework material includes: heat treatment of graphene using steam. The present invention develops a suitable preparation process that fully utilizes the excellent conductivity and flexibility of graphene to solve the problems of volume expansion and poor conductivity in the application of silicon-carbon anodes, thus solving a problem that urgently needs to be addressed in this field.

[0041] In this invention, the purpose of steam heat treatment is etching. For example, a steam generator is usually installed at the inlet of a tube furnace, and an inert gas is used as a carrier to heat up and perform etching. The carrier gas flow rate can be selected in a wide range, generally 100-200 sccm.

[0042] There are no special requirements for the rate of heating to the heat treatment temperature; it can generally be 1-10℃ / min, for example, 5℃ / min.

[0043] In this invention, various types of graphene can be used. The following is an illustrative description, but it does not limit the scope of the invention.

[0044] According to one embodiment of the present invention, preferably, the median particle size D50 of the graphene is 10 μm to 16 μm. This results in a carbon framework material with the advantages of moderate framework size and high silicon loading.

[0045] According to one embodiment of the present invention, preferably, the carbon content of the graphene is ≥90%; thereby having the advantage of high electrical conductivity.

[0046] According to one embodiment of the present invention, preferably, the specific surface area of ​​the graphene is 30 m². 2 / g~80m 2 / g.

[0047] In this invention, the heat treatment conditions can be selected from a wide range. According to a preferred embodiment of this invention, the heat treatment conditions include: a temperature of 600℃ to 900℃, and the heat treatment time can be adjusted as needed. For this invention, the preferred heat treatment time is 0.5h to 2h.

[0048] In this invention, after heat treatment, vacuum drying is performed to obtain a carbon skeleton material.

[0049] This invention provides the application of the silicon-carbon material described herein as a battery anode material; preferably, its application as a lithium battery anode material.

[0050] The present invention does not particularly limit the specific composition of the cathode material, and it can be a cathode material containing lithium element that is commonly used in the field.

[0051] According to the lithium-ion battery provided by the present invention, the separator can be selected from various separators used in lithium-ion batteries known to those skilled in the art, such as polypropylene microporous membrane, polyethylene felt, glass fiber felt or ultrafine glass fiber paper.

[0052] According to the lithium-ion battery provided by the present invention, the electrolyte can be various conventional electrolytes, such as non-aqueous electrolytes. The non-aqueous electrolyte is a solution of an electrolyte lithium salt in a non-aqueous solvent, and conventional non-aqueous electrolytes known to those skilled in the art can be used. For example, the electrolyte can be selected from at least one of lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), and lithium hexafluorosilicate (LiSiF6). The non-aqueous solvent can be selected from a mixed solution of chain esters and cyclic esters, wherein the chain ester can be at least one of dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), methyl propyl carbonate (MPC), and dipropyl carbonate (DPC). The cyclic ester can be at least one of ethylene carbonate (EC), propylene carbonate (PC), and vinylene carbonate (VC).

[0053] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0054] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0055] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0056] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0057] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0058] In the following examples and comparative examples, the electrochemical performance of the assembled lithium-ion batteries was tested using the Wuhan Landian Battery Testing System (CT2001B). Test conditions included: voltage range of 0.005V-1.5V and current range of 0.05A-2A. Ten coin cells were assembled for each sample, and battery performance was tested under the same voltage and current, with the average value taken.

[0059] In this invention, scanning electron microscopy (SEM) is used to characterize the morphology of the electrode material. Specifically, the scanning electron microscope is a TECNALG2F20 (200kV) model from FEI Corporation, USA. The test conditions are as follows: the sample is directly pressed onto a sample stage containing conductive tape, and then the microscope is inserted for observation. The observation is performed at a magnification of 8000x.

[0060] In this invention, the morphology of the electrode material was characterized using a JEM-2100 transmission electron microscope (TEM, HR-TEM) from Nippon Electron Ltd. Test conditions: The sample was placed on a copper support grid and then inserted into the electron microscope for observation. The observations were performed at magnifications of 17,000x and 380,000x.

[0061] In this invention, the specific surface area was measured using an ASAP2010 specific surface area and pore size distribution analyzer from Micromeritics, USA. Test conditions: temperature 77K, nitrogen atmosphere.

[0062] In this invention, Raman spectroscopy was performed using a 785nm wavelength laser as the excitation source and an Invia / Reflrx Laser Micro-Raman spectrometer. All samples were tested on clean glass slides. Specifically, the spectral density was measured in the 1250-1450 cm⁻¹ range. -1 The highest peak height I of the D peak (defect peak) within the wavelength range D 1500-1700cm -1 G peak (sp) in the wavelength range 2 The highest peak height (of hybrid carbon atom vibration peak) is I. G .

[0063] Example 1

[0064] (1) Take 100g of powdered graphene (parameters shown in Table 4) and place it in a tube furnace. Add a steam generator at the inlet of the tube furnace, and use nitrogen as the carrier gas for the entire system. Heat the tube furnace to 750℃ at 5℃ / min, then adjust the carrier gas flow rate to 100 sccm. Etching is performed at this temperature for 1 hour. After etching, the obtained graphene is vacuum dried to obtain a carbon framework material (properties shown in Table 1).

[0065] (2) The graphene obtained in step (1) is placed in a silane vapor deposition furnace, with silane as the silicon source, a flow rate of 220 sccm, a deposition time of 4 h, and a deposition temperature of 950 °C. After the reaction is completed, the obtained material is carefully taken out, which is the silicon-carbon material described in this invention (properties are shown in Table 2).

[0066] Figure 1 The image shows a SEM image of the silicon-carbon material described in the embodiment. As can be seen from the image, unlike conventional porous silicon-carbon or nanoparticle-supported silicon-carbon, the material obtained in this invention is a dense bulk at the magnification used for detection. Figure 2 TEM and HRTEM showed that there were no obvious grain boundaries between amorphous carbon and silicon, indicating that silicon was uniformly distributed on the surface of amorphous carbon and completely covered the carbon. Figure 3 The BET curve of the obtained material is shown; the BET value of the obtained material is 4.27m. 2 / g, similar to traditional graphite materials, does not present any processing difficulties. Figure 4 The image shows the Raman spectrum of the obtained material. It can be seen from the image that the obtained material exhibits high Raman performance at 1350 cm⁻¹. -1 -1650cm -1 The presence of D and G peaks within the range, along with an ID / IG ratio of 1.22, indicates that the silicon-carbon material exhibits numerous defects, providing more sites for supporting silicon as a porous carbon framework. At 470 cm⁻¹... -1 At the same location, a scattering vibration peak of amorphous silicon also appeared. Unlike previous observations of elemental silicon, this scattering vibration peak appeared at 12 cm⁻¹.-1 The blue shift indicates that silicon and carbon have achieved a uniform dispersion at the nanoscale, and the carbon surrounding silicon has altered its electron cloud distribution, causing the blue shift.

[0067] The electrical properties of the material obtained in Example 1 were then measured using a Blue Electric Battery testing system. The results showed that the silicon-carbon anode obtained in Example 1 had a specific capacity of 1870 mAh / g, an initial coulombic efficiency of 88.5%, and a capacity retention of 95% after 200 charge-discharge cycles at 0.2C / 0.2C rates. When compounded with natural graphite, the specific capacity was increased to 650 mAh / g. -1 The silicon-carbon anode was used, and the electrode expansion rate under full charge was measured using a coin cell. The surface electrode expansion rate was 22%, as shown in Table 3.

[0068] Example 2

[0069] (1) Take 100g of powdered graphene and place it in a tube furnace. Add a steam generator at the inlet of the tube furnace, and use nitrogen as the carrier gas for the entire system. Heat the tube furnace to 600℃ at 5℃ / min, and then adjust the carrier gas flow rate to 100sccm. Etching is performed at this temperature for 2 hours. After etching is completed, the obtained graphene is vacuum dried to obtain a carbon framework material.

[0070] (2) The graphene obtained in step (1) is placed in a silane vapor deposition furnace, with silane as the silicon source, a gas flow rate of 350 sccm, a deposition time of 6 h, and a deposition temperature of 1100 °C. After the reaction is completed, the obtained material is carefully taken out, which is the silicon-carbon material described in this invention.

[0071] The properties of the carbon skeleton materials are shown in Table 1;

[0072] The properties of silicon-carbon materials are shown in Table 2;

[0073] The electrical properties of the material are shown in Table 3.

[0074] Example 3

[0075] (1) Take 100g of powdered graphene and place it in a tube furnace. Add a steam generator at the inlet of the tube furnace, and use nitrogen as the carrier gas for the entire system. Heat the tube furnace to 900℃ at 5℃ / min, and then adjust the carrier gas flow rate to 120sccm. Etching is performed at this temperature for 2 hours. After etching is completed, the obtained graphene is vacuum dried to obtain a carbon framework material.

[0076] (2) The graphene obtained in step (1) is placed in a silane vapor deposition furnace with 40% by volume silicon tetrachloride and 60% by volume mixed gas as raw materials. The gas flow rate is 300 sccm, the deposition time is 6 h, and the deposition temperature is 1050 °C. After the reaction is completed, the obtained material is carefully taken out, which is the silicon-carbon material described in this invention.

[0077] The properties of the carbon skeleton materials are shown in Table 1;

[0078] The properties of silicon-carbon materials are shown in Table 2;

[0079] The electrical properties of the material are shown in Table 3.

[0080] Example 4

[0081] Water vapor etching was performed according to the method in Example 1, except that the median particle size of the graphene was 3 μm. The results are shown in Table 1.

[0082] The properties of the carbon skeleton materials are shown in Table 1;

[0083] The properties of silicon-carbon materials are shown in Table 2;

[0084] The electrical properties of the material are shown in Table 3.

[0085] Example 5

[0086] Water vapor etching was performed according to the method in Example 1, except that the median particle size of the graphene was 25 μm. The results are shown in Table 1.

[0087] The properties of the carbon skeleton materials are shown in Table 1;

[0088] The properties of silicon-carbon materials are shown in Table 2;

[0089] The electrical properties of the material are shown in Table 3.

[0090] Example 6

[0091] Vapor deposition was performed according to the method in Example 1, except that the deposition temperature was 550°C. The results are shown in Table 1.

[0092] Example 7

[0093] Graphene was subjected to steam treatment according to the method in Example 1, except that the steam treatment temperature was 720°C, the heating rate was 10°C / min, and steam was introduced after the furnace temperature reached the treatment temperature. The carrier gas flow rate was 100 sccm, and the etching time was 45 min. The results are shown in Table 1.

[0094] The properties of the carbon skeleton materials are shown in Table 1;

[0095] The properties of silicon-carbon materials are shown in Table 2;

[0096] The electrical properties of the material are shown in Table 3.

[0097] Comparative Example 1

[0098] Water vapor treatment was performed according to the method in Example 3, followed by mechanical mixing of nano-silicon with a D50 of 120 nm with a carbon framework. The results are shown in Table 1.

[0099] Table 1

[0100] Carbon skeleton materials ID / IG <![CDATA[Specific surface area m 2 / g]]> Example 1 1.22 390 Example 2 1.08 305 Example 3 1.5 500 Example 4 1.42 460 Example 5 1.1 323 Example 6 1.22 390 Example 7 1.35 420 Comparative Example 1 1.22 390

[0101] As can be seen from the results in Table 1, the carbon skeleton material of the present invention has a large number of defect sites.

[0102] Table 2

[0103]

[0104] Table 3

[0105]

[0106] Table 4

[0107] graphene Median particle size, μm <![CDATA[Specific surface area, m 2 / g]]> Carbon content, wt% Example 1 15 38 99.90％ Example 2 15 38 99.90％ Example 3 15 38 99.90％ Example 4 3 115 98.50％ Example 5 25 12 99.90％ Example 6 15 38 99.90％ Example 7 15 38 99.90％

[0108] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A silicon-carbon material, characterized in that, The silicon-carbon material includes a carbon skeleton and elemental silicon deposited on the carbon skeleton; a Raman spectrum of the silicon-carbon material has a D peak and a G peak in a wave number range of 1350 cm -1 -1650 cm -1 , and ID / IG is 1.0-1.5; the silicon-carbon material has a spectrum peak of elemental silicon in a wave number range of 460 cm -1 -480 cm -1 , and a blend of the silicon-carbon material and graphite has a specific capacity of greater than or equal to 600 mAh / g, and a volume expansion rate at a full charge state of less than or equal to 30%.

2. The silicon-carbon material of claim 1, wherein, The gram capacity of the silicon-carbon material is ≥ 1500 mAh / g; and / or the first coulombic efficiency is ≥ 85%.

3. The silicon-carbon material of claim 2, wherein, The gram capacity of the silicon-carbon material is ≥ 1800 mAh / g.

4. The silicon-carbon material of claim 1, wherein, The mass percentage content of the carbon skeleton is 30 wt% to 70 wt% based on the silicon-carbon material; and the mass percentage content of the silicon element is 30 wt% to 70 wt% based on the silicon-carbon material.

5. The silicon-carbon material of claim 4, wherein, The mass percentage content of the carbon skeleton is 40 wt% to 60 wt% based on the silicon-carbon material; and the mass percentage content of the silicon element is 40 wt% to 60 wt% based on the silicon-carbon material.

6. The silicon-carbon material of claim 1, wherein, The tap density of the silicon-carbon material is 0.6 g / cm 3 1.0 g / cm 3 ; and / or The particle size D10 of the silicon-carbon material is 1 μm to 3 μm, the particle size D50 is 5 μm to 8 μm, and the particle size D90 is 12 μm to 16 μm.

7. The silicon-carbon material of claim 6, wherein, The tap density of the silicon-carbon material is 0.8 g / cm 3 0.98 g / cm 3 .

8. The silicon-carbon material of claim 1, wherein, The silicon element in the silicon-carbon material is deposited on the carbon skeleton in the form of a thin film or a bulk; and / or The silicon-carbon material has a specific surface area of 1 m 2 / g ~ 5 m 2 / g, a pore volume of 0.3 cm 3 / g ~ 1.2 cm 3 / g.

9. A method of making the silicon-carbon material of any one of claims 1-8, wherein, The method comprises the following steps: Silicon element is deposited on the carbon skeleton material by vapor deposition method; the Raman spectrum of the carbon skeleton material has D peak and G peak in the wave number range of 1350 cm -1 -1650 cm -1 , and ID / IG is 1.0-1.5, and the specific surface area is 300-500 m 2 / g.

10. The preparation method of claim 9, wherein, The temperature of the vapor deposition is 800℃ to 1200℃; and / or The vapor deposition time is 2h to 8h; and / or The gas flow rate is 200sccm to 350sccm.

11. The production method according to claim 9, wherein The deposition silicon source is silane.

12. The method of making according to claim 11, wherein, The deposition silicon source is one or more of monosilane, disilane, chlorosilane.

13. The method of making according to claim 12, wherein, The deposition silicon source is one or more of monosilane, silicon tetrachloride, trichlorosilane.

14. The method of making according to claim 9, wherein, The preparation method of the carbon skeleton material comprises: heat treating graphene using water vapor, and then performing vacuum drying.

15. The preparation method of claim 14, wherein, The median particle size D50 of the graphene is 10 μm ~ 16 μm, the carbon content of the graphene is ≥ 90%, the specific surface area of the graphene is 30 m 2 / g ~ 80 m 2 / g.

16. The preparation method of claim 15, wherein, The heat treatment conditions comprise: a temperature of 600℃ to 900℃, and / or a time of 0.5h to 2h.

17. Use of the silicon-carbon material of any one of claims 1-8 as a battery negative electrode material.

18. Use of the silicon-carbon material of any one of claims 1-8 as a lithium battery negative electrode material.

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