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

Abstract

The application discloses a silicon-carbon negative electrode material, a preparation method, application and a battery. The preparation method of the silicon-carbon negative electrode material comprises the following steps: performing methane gas phase carbon coating on a silicon source to obtain the silicon-carbon negative electrode material; wherein, when the methane gas phase carbon coating is performed, the vacuum degree of the system is 300-5000 Pa; and the mass-volume ratio of the silicon source and methane is 1 kg:(10-150) L. The uniformity and coverage of the coating layer on the surface of the silicon source of the silicon-carbon negative electrode material are better, the carbon deposition layer has a special surface structure, the volume change of the negative electrode material in the charging and discharging process can be buffered, and the negative electrode material can realize better electrochemical performance.

Description

Technical Field

[0001] This invention relates to a silicon-carbon anode material, its preparation method, its application, and its battery. Background Technology

[0002] Lithium-ion batteries, as efficient and environmentally friendly energy storage devices, are widely used in electric vehicles, mobile devices, and other fields. In lithium-ion batteries, the anode material is one of the key factors affecting battery performance. Silicon suboxide, as a novel anode material, possesses high capacity, good electrochemical performance, and stability, and is considered an ideal anode material for next-generation lithium-ion batteries. However, silicon suboxide anode materials exhibit severe volume effects during charge and discharge, leading to a decrease in battery cycle stability and rate performance. Therefore, surface modification is a common improvement measure.

[0003] CN116995202A discloses a method for preparing a non-metallic element-doped carbon-coated silicon-oxygen composite anode material. This method uses sodium carboxymethyl cellulose and thiourea to form a tight cross-linked structure on the surface of silicon oxide through an organic cross-linking reaction. After heat treatment, a uniformly distributed and stable nitrogen and sulfur-doped carbon coating layer is formed, which can prevent the silicon oxide from undergoing large volume expansion. However, the uniformity and coverage of the structure formed by organic polymer cross-linking on the SiOx surface may be limited, and a large amount of organic polymer needs to be used in the production process, which may increase costs and environmental burden.

[0004] Carbon coating of silicon suboxide anodes can improve their capacity and first-cycle efficiency. Currently, the mainstream coating gas sources are methane or acetylene. Methane coating can effectively improve lithium-ion intercalation / deintercalation performance; however, methane cracking requires high temperatures, and excessively high temperatures can degrade material properties and limit the maximum operating temperature of equipment, resulting in low methane utilization. Acetylene coating has a lower cracking temperature, but the carbon layer structure formed by acetylene cracking is relatively dense, which restricts the lithium-ion intercalation / deintercalation process, leading to poor cycle performance. Summary of the Invention

[0005] The technical problem to be solved by this invention is to overcome the defect of poor electrochemical performance of silicon-carbon anode materials in the prior art, and to provide a silicon-carbon anode material, preparation method, application, and battery. The silicon-carbon anode material of this invention has better uniformity and coverage of the coating layer on the surface of the silicon source, and the carbon deposition layer has a special surface structure that can buffer the volume change of the anode material during charging and discharging, thus enabling the anode material to achieve better electrochemical performance.

[0006] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0007] This invention provides a method for preparing a silicon-carbon anode material, which includes the following steps: coating a silicon source with methane gas phase carbon to obtain the silicon-carbon anode material;

[0008] When the methane gas phase is carbon coated, the vacuum degree of the system is 300-5000 Pa; the mass-to-volume ratio of the silicon source and the methane is 1 kg:(10-150) L.

[0009] In this invention, the silicon source can be a silicon-containing particulate material conventional in the art, such as silicon and / or silicon suboxide.

[0010] In this invention, the D50 particle size of the silicon source can be 3-10 μm, for example 5 μm.

[0011] In this invention, the equipment for methane gas-phase carbon coating can be a rotary kiln. Preferably, before performing the methane gas-phase carbon coating, the silicon source is generally placed in the rotary kiln for gas replacement. The gas used for gas replacement is preferably nitrogen. The nitrogen gas flow rate can be 3-10 L / min, for example, 5 L / min. The nitrogen introduction time can be 1-3 hours. The endpoint of the gas replacement can be when the oxygen content in the rotary kiln is lower than 300 ppm.

[0012] In this invention, when methane is coated with carbon in the gas phase, the vacuum degree of the system represents the value of the system's absolute pressure being lower than atmospheric pressure, i.e., vacuum degree = atmospheric pressure - absolute pressure. The atmospheric pressure refers to standard atmospheric pressure, which is 101.325 kPa at 0°C.

[0013] In this invention, when the methane gas phase is carbon coated, the vacuum degree of the system is preferably 500-3000 Pa, for example 800 Pa, 1000 Pa or 2000 Pa.

[0014] In this invention, the inventors discovered during the research and development process that low-pressure gas phase (vacuum degree of 300-5000Pa) deposition not only enables methane to achieve a better cracking rate, but also helps to improve the purity of the carbon coating layer.

[0015] In this invention, during the methane gas-phase carbon coating, the system temperature can be 500-1200℃, preferably 600-1000℃, for example 800 or 900℃. The system temperature indicates that during the methane gas-phase carbon coating, the system temperature remains within the above range.

[0016] In this invention, the time for methane gas phase carbon coating can be 2-8 hours, preferably 3-6 hours, for example 5 hours.

[0017] In this invention, the gas flow rate of methane can be 0.5-2 L / min, preferably 0.7-1.5 L / min, for example 1 L / min.

[0018] In this invention, a carrier gas is generally introduced during the methane gas phase carbon coating process. The purpose of the carrier gas is to maintain a constant vacuum level in the system. The carrier gas can be nitrogen. The flow rate of the carrier gas can be 0.1-1 L / min, preferably 0.3-0.8 L / min.

[0019] In this invention, the mass-to-volume ratio of the silicon source and the methane is preferably 1 kg:(30-120) L, for example 1 kg:60 L.

[0020] In this invention, preferably, boron deposition is performed before the silicon source is coated with methane vapor phase carbon, for example, including the following steps: sequentially performing boron source vapor phase deposition and methane vapor phase carbon coating on the silicon source.

[0021] The boron source can be a conventional boron-containing gas in the art. Preferably, the boron source is diborane (B₂H₄) or butorane (B₄H₂O). 10 ) and hexaborides (B6H 10 One or more of the following, such as diborane (B2H4).

[0022] During the boron source vapor deposition, the vacuum degree of the system refers to the value of the system's absolute pressure being lower than the atmospheric pressure, i.e., vacuum degree = atmospheric pressure - absolute pressure. The atmospheric pressure refers to standard atmospheric pressure, which is 101.325 kPa at 0°C.

[0023] During the boron source vapor deposition, the vacuum level of the system is preferably 300-5000 Pa, more preferably 500-3000 Pa, such as 800 Pa, 1000 Pa or 2000 Pa.

[0024] During the research and development process, the inventors discovered that borane can achieve a better cracking rate under low-pressure gas phase (vacuum degree of 300-5000Pa) deposition.

[0025] During the boron source vapor deposition, the system temperature is preferably 300-900℃, for example, 600 or 800℃. This system temperature indicates that the system temperature remains within the above range during methane vapor-phase carbon coating.

[0026] During the research and development process, the inventors discovered that when a boron source is introduced at 300-900℃, the formed boron deposition layer can be an amorphous boron structure, and the amorphous boron structure is conducive to the deposition of methane on the surface of the boron deposition layer.

[0027] The preferred time for the boron source vapor deposition is 1-5 hours, for example, 2 or 3 hours.

[0028] The flow rate of the gas introduced from the boron source is preferably 1-8 L / min, more preferably 2-6 L / min, for example 3 L / min or 5 L / min.

[0029] When the boron source is introduced, a carrier gas is generally also introduced. The purpose of the carrier gas is to maintain a constant vacuum level in the system. The carrier gas can be nitrogen. The flow rate of the carrier gas can be 0.1-1 L / min, preferably 0.3-0.8 L / min.

[0030] The mass-to-volume ratio of the silicon source and the boron source is preferably 1 kg:(12-480) L, more preferably 1 kg:(20-144) L, for example 1 kg:24 L, 1 kg:72 L or 1 kg:120 L.

[0031] The present invention also provides a silicon-carbon anode material, which is prepared by the preparation method described above.

[0032] The present invention also provides a silicon-carbon anode material, comprising a silicon source and a carbon deposition layer covering the surface of the silicon source; the carbon deposition layer is a disordered carbon scaly spike structure;

[0033] The silicon-carbon anode material contains 1%-5% carbon.

[0034] In this invention, the carbon disordered scaly spike structure is a structure formed after the cracking of methane, as shown in the schematic diagram below. Figure 1 As shown.

[0035] In this invention, the carbon content in the silicon-carbon anode material is preferably 1.5%-4%, for example 1.75%, 3.01%, 3.26%, 3.32%, 3.55%, 3.75%, 3.76%, or 3.87%.

[0036] In this invention, the silicon-carbon anode material preferably also contains a boron deposition layer. The boron deposition layer may be an amorphous boron structure.

[0037] The boron content in the silicon-carbon anode material can be 1%-3%, preferably 1.3%-2.5%, for example 1.55%, 1.56%, 1.57%, 1.86%, 2.03%, 2.14% or 2.23%.

[0038] In the silicon-carbon anode material, the thickness of the boron deposition layer can be 5-10 nm, preferably 6-9 nm, such as 6.7, 7.0, 7.3, 7.4, 7.8, 8.4 or 8.6 nm.

[0039] In a preferred embodiment, the silicon-carbon anode material includes a silicon source, a boron deposition layer covering the surface of the silicon source, and a carbon deposition layer covering the surface of the boron deposition layer.

[0040] The boron deposition layer has an amorphous boron structure; the carbon deposition layer has a disordered carbon scaly spike structure.

[0041] In the silicon-boron-carbon anode material, the boron content is 1%-3% and the carbon content is 1%-5%.

[0042] In this invention, the D50 particle size of the silicon-carbon anode material can be 3-10 μm, preferably 4-6 μm, for example 5.1, 5.3, 5.4 or 5.5 μm.

[0043] In this invention, the specific surface area of ​​the silicon-carbon anode material can be 1.2-2 m². 2 / g, preferably 1.4-1.8m 2 / g, for example 1.41, 1.49, 1.55, 1.6, 1.62, 1.63, 1.65, 1.68 or 1.71m 2 / g.

[0044] In this invention, the tap density of the silicon-carbon anode material can be 0.8-1.2 g / cm³. 3 The preferred concentration is 0.9-1 g / cm³. 3 For example, 0.96, 0.97, 0.98, or 0.99 g / cm³ 3 .

[0045] In this invention, the moisture content of the silicon-carbon anode material can be ≤0.05%, for example, 0.01%, 0.02%, or 0.03%.

[0046] The present invention also provides an application of the silicon-carbon anode material as described above in a battery.

[0047] The present invention also provides a battery comprising the silicon-carbon anode material as described above.

[0048] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0049] The reagents and raw materials used in this invention are all commercially available.

[0050] The positive and progressive effects of this invention are as follows:

[0051] (1) In this invention, methane can achieve a better cracking rate under low-pressure deposition. The silicon-carbon anode material obtained has better uniformity and coverage of the coating layer on the surface of the silicon source, and has better electrochemical performance, such as higher initial efficiency.

[0052] (2) In a preferred embodiment, the boron deposition layer in the silicon-carbon anode material can increase the carrier concentration of silicon suboxide, promote electron migration in the material, and improve the conductivity of the anode material. The carbon deposition layer has a special surface structure, which can buffer the volume change of the anode material during charging and discharging, so that the anode material can achieve better electrochemical performance. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the structure of the silicon-carbon anode materials prepared in Examples 1-8.

[0054] Figure 2 This is a schematic diagram of the silicon-carbon anode material prepared in Example 9.

[0055] Figure 3 This is a TEM image of the silicon-carbon anode material prepared in Comparative Example 1.

[0056] Figure 4 This is a schematic diagram of the carbon deposition layer formed after acetylene cracking.

[0057] Figure 5 This is a TEM image of the silicon-carbon anode material prepared in Example 2.

[0058] Figure 6 This is a schematic diagram of the carbon deposit layer formed after methane cracking.

[0059] Explanation of reference numerals in the attached figures:

[0060] 1-Silicon source; 2-Carbon deposition layer; 3-Boron deposition layer. Detailed Implementation

[0061] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0062] Example 1

[0063] (1) Weigh 5 kg of silicon suboxide material (D50 is 5 μm), put the material into the rotary heating furnace, and purge with nitrogen at a flow rate of 5 L / min for about 1 hour for gas replacement. When the oxygen content is less than 300 ppm, adjust the nitrogen flow rate to 0.1 L / min. The rotary furnace starts heating and rises to 900 ℃. Then close the gas inlet valve.

[0064] (2) Open the vacuum pump and the evacuation valve to evacuate. When the vacuum level reaches 1000Pa, introduce the reaction gas diborane and the carrier gas nitrogen. The flow rate of diborane is 1L / min and the flow rate of carrier gas is 0.8L / min. Keep the temperature constant at 900℃ for 2 hours. The vacuum pump interlock pressure control keeps the vacuum level within 1000Pa.

[0065] (3) After the reaction is completed, the borane supply is turned off, and the vacuum pump interlock pressure control is used to control the vacuum level within 1000 Pa. The rotary kiln is heated to 1000°C, and the reaction gas methane and the carrier gas nitrogen are introduced. The flow rate of methane is 1 L / min, and the flow rate of the carrier gas is 0.8 L / min. The temperature is kept constant at 1000°C for 5 hours. After the reaction is completed, the temperature is allowed to drop naturally. After the equipment temperature drops to 60°C, the equipment is opened to discharge the material and carbon-coated composite material is obtained.

[0066] Example 2

[0067] The only difference from Example 1 is that the vacuum degree in step (2) is 800 Pa.

[0068] Example 3

[0069] The only difference from Example 1 is that the vacuum degree in step (2) is 500 Pa.

[0070] Example 4

[0071] The only difference from Example 1 is that the temperature at which methane is introduced in step (3) is 800°C.

[0072] Example 5

[0073] The only difference from Example 1 is that the flow rate of methane introduced in step (3) is 0.5 L / min.

[0074] Example 6

[0075] The only difference from Example 1 is that the flow rate of methane introduced in step (3) is 2 L / min.

[0076] Example 7

[0077] The only difference from Example 1 is that the flow rate of borane in step (2) is 3 L / min.

[0078] Example 8

[0079] The only difference from Example 1 is that the flow rate of borane in step (2) is 5 L / min.

[0080] Example 9

[0081] The only difference from Example 1 is that step (2) is omitted and borane is not added.

[0082] Comparative Example 1

[0083] The only difference from Example 5 is that step (2) is omitted and methane in step (3) is replaced with acetylene.

[0084] Comparative Example 2

[0085] The only difference from Example 1 is that the absolute pressure of the system in steps (2) and (3) is atmospheric pressure, that is, the vacuum degree is 0 Pa. Atmospheric pressure is standard atmospheric pressure, that is, 101.325 kPa at 0 °C.

[0086] Comparative Example 3

[0087] The only difference from Example 1 is that the vacuum degree in step (2) is 100 Pa.

[0088] Example 1

[0089] The silicon-carbon anode materials prepared in the above examples and comparative examples were tested for TEM, D50 particle size, specific surface area, tap density, and moisture content. The results are shown in Table 1 and... Figure 2-3 As shown.

[0090] The D50 particle size was measured using a Mastersizer 2000 laser particle size analyzer with a range of 0.02 μm to 2000 μm and a light-blocking degree of 5-15%. The specific surface area was measured using a NOVATouch fully automated specific surface area and pore size analyzer with a specific surface area measurement range as low as 0.01 μm. 2 / g; the tap density was tested using a AUTO TAP tap density meter with an amplitude of 3 mm (0.125 inches) and a vibration frequency of 260 / min.

[0091] Figure 1 This is a schematic diagram of the structure of the silicon-carbon anode materials prepared in Examples 1-8. As shown in the figure, the silicon-carbon anode material includes a silicon source, a boron deposition layer coated on the surface of the silicon source, and a carbon deposition layer coated on the surface of the boron deposition layer;

[0092] The boron deposition layer has an amorphous boron structure, and the carbon deposition layer has a disordered carbon scaly spike structure.

[0093] Figure 2 This is a schematic diagram of the silicon-carbon anode material prepared in Example 9. As shown in the figure, the silicon-carbon anode material includes a silicon source and a carbon deposition layer covering the surface of the silicon source; the carbon deposition layer has a disordered, scaly, spike-like carbon structure.

[0094] Figure 3 This is a TEM image of the silicon-carbon anode material prepared in Comparative Example 1. Figure 4 This is a schematic diagram of the carbon deposition layer formed after acetylene cracking. Figure 3 and Figure 4 It can be seen that the carbon coating layer of the negative electrode material is an ordered layer, which is not conducive to the insertion and extraction of lithium ions during charging and discharging.

[0095] Figure 5This is a TEM image of the silicon-carbon anode material prepared in Example 2. Figure 6 This is a schematic diagram of the carbon deposition layer formed after methane cracking. Figure 5 and Figure 6 It can be seen that the carbon coating layer of this negative electrode material has a disordered scaly spike structure, which is more conducive to lithium ion insertion and extraction, thereby improving the cycle performance of lithium-ion battery materials.

[0096] Table 1

[0097]

[0098] The above cases demonstrate that depositing boron and carbon layers on the surface of silicon suboxide using low-pressure vapor deposition did not cause an increase in the size of the silicon crystals in the material core.

[0099] Example 2

[0100] The carbon and boron contents of the silicon-carbon anode materials prepared in the above examples and comparative examples were tested. The testing methods were as follows: the carbon content was measured using a CS-2800 high-frequency infrared carbon-sulfur analyzer with a sensitivity of 0.01 ppm and an analysis time of 30-40 seconds. The boron content was measured using an Avio analyzer. TM The 200 inductively coupled plasma atomic emission spectrometer had a precision of ≤1.0% and a stability RSD of ≤1.5%. The results are shown in Table 2.

[0101] Table 2

[0102] Serial Number Carbon content % Boron content % Boron deposition layer thickness nm Example 1 3.75 2.03 7.8 Example 2 3.32 1.86 7.3 Example 3 3.01 1.57 6.7 Example 4 3.55 1.56 7.0 Example 5 3.26 1.57 7.3 Example 6 3.87 1.55 7.4 Example 7 3.76 2.14 8.4 Example 8 3.75 2.23 8.6 Example 9 1.75 0 0 Comparative Example 1 0.96 0 0 Comparative Example 2 1.06 1.37 5.2 Comparative Example 3 1.58 1.63 5.6

[0103] Comparing carbon content revealed that the amorphous boron structure facilitates methane deposition on the material surface, further improving the material's conductivity.

[0104] Example 3

[0105] The silicon-carbon anode material prepared in the above embodiments and comparative examples was mixed with Super P conductive agent and polyacrylic acid binder LA-132 (15wt%) in a mass ratio of 7:2:1 to form a slurry. This slurry was then coated onto copper foil, and after vacuum drying, the copper foil was cut into electrode sheets with a diameter of 12 mm (electrode loading of 2.5 mg / cm²). 2 The 2032 coin cell half-cells were assembled in an argon-filled glove box and then tested. A lithium metal sheet was used as the counter electrode, and a Celgard 2400 separator was used. After the packaged coin cells were placed in the glove box for 12 hours, constant current charge-discharge cycle tests were performed at a voltage range of 0.01-2V and a current density of 50mA / g. The test results are shown in Table 3.

[0106] Table 3

[0107] Serial Number Discharge capacity mAh / g First-time efficiency % % capacity retention after 10 weeks Example 1 1677.5 77.3 89 Example 2 1652.2 76.5 84 Example 3 1648.3 73.1 76 Example 4 1560.7 75.3 83 Example 5 1645.4 76.4 84 Example 6 1673.1 76.8 88 Example 7 1643.8 75.7 85 Example 8 1640.9 74.7 80 Example 9 1634.2 75.8 68 Comparative Example 1 1620.5 75.6 55 Comparative Example 2 1640.3 76.1 70 Comparative Example 3 1631.6 75.3 73

[0108] The above cases demonstrate that materials prepared under low pressure exhibit high capacity retention after 10 weeks, indicating good cycle stability.

[0109] By changing parameters such as gas source, gas flow rate, and pressure, it can be clearly seen that compared with acetylene cracking carbon coating, methane cracking carbon coating material has higher discharge capacity, initial coulombic efficiency, and capacity retention rate after 10 weeks.

Claims

1. A method for preparing a silicon-carbon negative electrode material, characterized by, It includes the following steps: sequentially performing boron source vapor deposition and methane vapor phase carbon coating on a silicon source to obtain the silicon-carbon anode material; Wherein, the vacuum degree of the system is 500-1000 Pa during the vapor deposition of the boron source; the vacuum degree of the system is 500-1000 Pa during the carbon coating of the methane vapor phase; the mass-to-volume ratio of the silicon source to the methane is 1 kg: (30-120) L; the type of the boron source is diborane; the mass-to-volume ratio of the silicon source to the boron source is 1 kg: (24-120) L.

2. The method for preparing a silicon-carbon negative material according to claim 1, characterized in that, The preparation method of the silicon-carbon anode material satisfies one or more of the following conditions: (1) The silicon source is silicon and / or silicon suboxide; (2) The D50 particle size of the silicon source is 3-10 μm; (3) When methane is coated with carbon in the gas phase, the vacuum degree of the system is 800-1000 Pa; (4) When methane gas phase carbon coating is used, the temperature of the system is 500-1200℃; (5) The time for carbon coating of the methane gas phase is 2-8 hours; (6) The gas flow rate of the methane is 0.5-2 L / min; and, (7) The mass-to-volume ratio of the silicon source and the methane is 1 kg: (30-60) L.

3. The method for preparing a silicon-carbon negative material according to claim 1, wherein, The preparation method of the silicon-carbon anode material satisfies one or more of the following conditions: (1) The D50 particle size of the silicon source is 5 μm; (2) When the methane gas phase is carbon coated, the vacuum degree of the system is 800 or 1000 Pa; (3) When methane gas phase carbon coating is used, the temperature of the system is 600-1000℃; (4) The time for carbon coating of the methane gas phase is 3-6 hours; (5) The gas flow rate of the methane is 0.7-1.5 L / min; (6) The mass-to-volume ratio of the silicon source and the methane is 1 kg: 60 L.

4. The method for preparing the silicon-carbon anode material as described in claim 3, characterized in that, The preparation method of the silicon-carbon anode material satisfies one or more of the following conditions: (1) When methane gas phase carbon coating is used, the temperature of the system is 800 or 900℃; (2) The time for carbon coating of the methane gas phase is 5 hours; (3) The gas flow rate of methane is 1 L / min.

5. The method for preparing a silicon-carbon negative material according to claim 1, wherein, The preparation method of the silicon-carbon anode material satisfies one or more of the following conditions: (1) The vacuum degree of the system during the boron source vapor deposition is 800-1000 Pa; (2) The temperature of the system during the boron source vapor deposition is 300-900℃; (3) The time for the boron source vapor deposition is 1-5 hours; (4) The flow rate of the gas introduced into the boron source is 1-8 L / min; and, (5) The mass-to-volume ratio of the silicon source and the boron source is 1 kg: 24 L, 1 kg: 72 L or 1 kg: 120 L.

6. The method for preparing a silicon-carbon negative material according to claim 5, characterized in that, The preparation method of the silicon-carbon anode material satisfies one or more of the following conditions: (1) During the boron source vapor deposition, the vacuum degree of the system is 800 or 1000 Pa; (2) The temperature of the system during the boron source vapor deposition is 600 or 800℃; (3) The time for the boron source vapor deposition is 2 or 3 hours; (4) The flow rate of the gas introduced into the boron source is 2-6 L / min.

7. The method for preparing a silicon-carbon negative material according to claim 6, characterized in that, The flow rate of the gas introduced from the boron source is 3 L / min or 5 L / min.

8. A silicon-carbon negative electrode material, characterized by, It is prepared by any one of the preparation methods described in claims 1-7.

9. The silicon-carbon negative electrode material of claim 8, wherein, The silicon-carbon anode material includes a silicon source and a carbon deposition layer covering the surface of the silicon source; the carbon deposition layer has a disordered carbon scaly spike structure. The silicon-carbon anode material contains 1%-5% carbon.

10. The silicon-carbon negative electrode material of claim 8, wherein, The silicon-carbon anode material satisfies one or more of the following conditions: (1) The carbon content in the silicon-carbon anode material is 1.5%-4%; (2) The D50 particle size of the silicon-carbon anode material is 3-10 μm; (3) the specific surface area of the silicon-carbon negative electrode material is 1.2-2 m 2 / g; (4) the tap density of the silicon-carbon negative electrode material is 0.8-1.2 g / cm 3 .

11. The silicon-carbon negative electrode material of claim 10, wherein, The silicon-carbon anode material satisfies one or more of the following conditions: (1) The carbon content in the silicon-carbon anode material is 1.75%, 3.01%, 3.26%, 3.32%, 3.55%, 3.75%, 3.76% or 3.87%; (2) The D50 particle size of the silicon-carbon anode material is 4-6 μm; (3) the specific surface area of the silicon-carbon negative electrode material is 1.4-1.8 m 2 / g; (4) the tap density of the silicon-carbon negative electrode material is 0.9-1 g / cm 3 .

12. The silicon-carbon negative electrode material of claim 11, wherein, The silicon-carbon anode material satisfies one or more of the following conditions: (1) The D50 particle size of the silicon-carbon anode material is 5.1, 5.3, 5.4 or 5.5 μm; (2) The specific surface area of ​​the silicon-carbon anode material is 1.41, 1.49, 1.55, 1.6, 1.62, 1.63, 1.65, 1.68 or 1.71 m². 2 / g; (3) the tap density of the silicon-carbon negative electrode material is 0.96, 0.97, 0.98 or 0.99 g / cm 3 .

13. The silicon-carbon negative electrode material of claim 8, wherein, The silicon-carbon anode material also contains a boron deposition layer.

14. The silicon-carbon negative electrode material of claim 13, wherein, The silicon-carbon anode material satisfies one or more of the following conditions: (1) The boron deposition layer has an amorphous boron structure; (2) The boron content in the silicon-carbon anode material is 1%-3%; (3) In the silicon-carbon anode material, the thickness of the boron deposition layer is 5-10 nm.

15. The silicon-carbon negative electrode material of claim 14, wherein, The silicon-carbon anode material satisfies (1) and / or (2) of the following conditions: (1) The boron content in the silicon-carbon anode material is 1.3%-2.5%; (2) In the silicon-carbon anode material, the thickness of the boron deposition layer is 6-9 nm.

16. The silicon-carbon negative electrode material of claim 15, wherein, The silicon-carbon anode material satisfies (1) and / or (2) of the following conditions: (1) In the silicon-carbon anode material, the boron content is 1.55%, 1.56%, 1.57%, 1.86%, 2.03%, 2.14% or 2.23%; (2) In the silicon-carbon anode material, the thickness of the boron deposition layer is 6.7, 7.0, 7.3, 7.4, 7.8, 8.4 or 8.6 nm.

17. The application of a silicon-carbon anode material as described in any one of claims 8-16 in a battery.

18. A battery, characterized in that, It includes the silicon-carbon anode material as described in any one of claims 8-16.

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