Method for recycling high-carbon content silicon monoxide negative electrode material in industrial production

Abstract

The present application relates to the technical field of high-carbon material recycling, and in particular to a method for recycling high-carbon silicon monoxide negative electrode material in industrial production. The method comprises the following steps: 1) carbon-coating silicon monoxide material to provide first silicon monoxide-carbon-coated negative electrode material and high-carbon material; 2) performing carbon-burning treatment on the high-carbon material provided in step 1) to provide carbon-burned material; and 3) carbon-coating the carbon-burned material provided in step 2) to provide second silicon monoxide-carbon-coated negative electrode material. Compared with the prior art, the present application can recycle solid waste high-carbon material and achieve the specific capacity of the original silicon monoxide negative electrode material; at the same time, the low expansion coefficient and safety performance make the application range involve the fields of consumer electronics and electric vehicles; and the recycling method is simple, easy to control and easy to realize large-scale recycling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-carbon material recycling, in particular to a method for recycling high-carbon silicon monoxide negative material in industrial production. BACKGROUND

[0002] Silicon monoxide (SiOx) as a lithium ion battery negative material has a high theoretical specific capacity (~2043 mAh / g) and a suitable delithiation potential (~<0.5V), and is abundant in raw materials, low in manufacturing cost, and friendly to the environment, and is considered to be a potential candidate material for the next generation of high-energy-density lithium ion battery negative electrodes.

[0003] However, SiOx has a serious volume effect (~200%) during the delithiation and lithium intercalation process, which easily leads to material particle pulverization and shedding, seriously affecting the interface stability and electrochemical performance of the SiOx negative electrode. Carbon coating on the surface of SiOx is a common method to improve the interface properties of the electrode material. The carbon layer can protect the material surface well and act as a buffer layer for the volume effect of SiO during delithiation and lithium intercalation, which can effectively avoid the continuous reaction of the fresh surface of the electrode with the electrolyte to generate SEI film during the charging and discharging process; on the other hand, it can improve the electrical conductivity of the electrode material.

[0004] Currently, the carbon-coated silicon monoxide negative material in industrial production is being optimized in terms of capacity, initial efficiency and other performance parameters, but during the production process, some high-carbon materials are produced that do not meet market demand and become derivative materials. If not recycled, this part of the material becomes solid waste, wasting production resources. However, in actual production, after CVD carbon coating of silicon monoxide, 4-6% of high-carbon material is produced, which has a low capacity (≤1400 mAh / g) and does not meet the negative material use standard. Therefore, how to fully utilize these high-carbon materials for the production of lithium ion battery negative materials has not been truly solved. Therefore, how to efficiently utilize high-carbon materials to meet the electrochemical performance requirements of silicon oxygen negative materials is still the focus of current research. SUMMARY

[0005] The present application is to solve the above problems, and in view of the technical problem that the high-carbon silicon oxygen material cannot be fully utilized in the prior art, the present application aims to provide a method for recycling high-carbon silicon monoxide negative material in industrial production, by carbonizing the high-carbon material to reduce the carbon content to below 1%, and then carbon-coating the carbonized material again, the obtained silicon oxygen negative material can achieve the capacity of standard products and meet the basic electrochemical performance requirements of silicon oxygen negative materials, realizing the recycling of high-carbon materials.

[0006] The first aspect of the present application provides a method for recycling high-carbon content silicon monoxide negative electrode material in industrial production, the method comprising the following steps:

[0007] 1) carbon-coating the silicon monoxide material to provide a first silicon monoxide carbon-coated negative electrode material and high-carbon material;

[0008] 2) performing carbon-burning treatment on the high-carbon material provided in step 1) to provide carbon-burned material;

[0009] 3) carbon-coating the carbon-burned material provided in step 2) to provide a second silicon monoxide carbon-coated negative electrode material.

[0010] The second aspect of the present application provides a silicon monoxide carbon-coated negative electrode material, which is prepared by the method according to the first aspect of the present application.

[0011] The third aspect of the present application provides the use of the silicon monoxide carbon-coated negative electrode material according to the second aspect of the present application in the fields of consumer electronics and electric vehicles.

[0012] The present application has the following beneficial effects:

[0013] In large-scale commercial production, the generation of high-carbon material is essential. The present application re-performs decarburization on the high-carbon material produced in industrial production and performs secondary carbon-coating, thereby achieving solid waste recycling and providing a good recycling method for industrial production.

[0014] Compared with the prior art, the present application can recycle the solid waste high-carbon material and achieve the same specific capacity as the original silicon monoxide negative electrode material. At the same time, the low expansion coefficient and safety performance make it applicable to the fields of consumer electronics and electric vehicles. After carbon-burning, the increased silicon dioxide content is less than 3%, which has little effect on the specific capacity and improves the cycle stability. The recycling method of the present application is simple, easy to control, and easy to realize large-scale recycling. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The electron microscope picture of the first silicon monoxide carbon-coated negative electrode material;

[0016] Figure 2 The electron microscope picture of the carbon-burned material;

[0017] Figure 3 The electron microscope picture of the second silicon monoxide carbon-coated negative electrode material obtained by re-carbon-coating the carbon-burned material. DETAILED DESCRIPTION

[0018] Hereinafter, the embodiments of the specifically disclosed method for recycling high-carbon content silicon monoxide negative electrode material in industrial production will be described in detail.

[0019] The application can achieve the gram capacity of the standard product, meet the basic electrochemical performance requirements of the silicon-oxygen negative electrode material, realize the recycling of high-carbon materials, and increase the silicon dioxide content by less than 3% after the carbonization is completed, which has little effect on the gram capacity and improves the cycle stability. Although silicon monoxide itself will react to form silicon dioxide during heating, this silicon dioxide is essentially not intended to be obtained by the application because the increase in silicon dioxide will affect the gram capacity and the initial coulomb efficiency of the material, so the applicant hopes to remove this part of the silicon dioxide by pickling, but the overall performance of the material decreases after pickling, so the applicant further controls the reaction temperature and time to make the silicon dioxide generated in the subsequent carbonization process less than 3%, and through the control of the amount, it is ensured that the part of the silicon dioxide has little effect on the electrochemical performance. It is found that although it will have a certain effect on the electrochemical performance (which can be ignored), but this part of the silicon dioxide has high mechanical strength and good stability, which improves the cycle stability of the target negative electrode material to some extent. On this basis, the application is completed.

[0020] Method for recycling high carbon content silicon monoxide negative electrode material in industrial production

[0021] The application provides a method for recycling high-carbon silicon monoxide negative electrode material in industrial production, which comprises the following steps:

[0022] 1) carbon-coating the silicon monoxide material to provide a first silicon monoxide carbon-coated negative electrode material and high-carbon material;

[0023] 2) carbonizing the high-carbon material provided in step 1) to provide carbonized material;

[0024] 3) carbon-coating the carbonized material provided in step 2) to provide a second silicon monoxide carbon-coated negative electrode material.

[0025] The method for recycling high-carbon silicon monoxide negative electrode material in industrial production provided by the application comprises the following steps:

[0026] In step 1) of the application, the Dv50 of the silicon monoxide (SiOx) material is 7-8 μm. The Dv50 is the particle size corresponding to 50% of the volume distribution. Alternatively, the Dv50 of the silicon monoxide (SiOx) material may, for example, be 7-7.5 μm or 7.5-8 μm.

[0027] In step 1) of the application, the silicon monoxide material is put into a coating furnace for carbon coating.

[0028] In step 1) of the present application, the feeding speed of the silicon monoxide material is 10 kg / h to 100 kg / h. Alternatively, the feeding speed of the silicon monoxide material may, for example, be 10 kg / h to 40 kg / h, 40 kg / h to 60 kg / h, or 60 kg / h to 100 kg / h, etc. Preferably, the feeding speed of the silicon monoxide material may, for example, be 40 kg / h to 60 kg / h.

[0029] In step 1) of the present application, the temperature of the carbon coating is 850℃ to 1050℃. Alternatively, the temperature of the carbon coating is 850℃ to 900℃, 900℃ to 1000℃, or 1000℃ to 1050℃, etc. Preferably, the temperature of the carbon coating is 900℃ to 1000℃.

[0030] In step 1) of the present application, the gas for carbon coating is a hydrocarbon small molecule gas; wherein the hydrocarbon small molecule gas is selected from methane and / or acetylene. The gas source flow rate is 10 L / min to 100 L / min. Alternatively, the gas source flow rate is 10 L / min to 40 L / min, 40 L / min to 75 L / min, or 75 L / min to 100 L / min, etc. Preferably, the gas source flow rate is 40 L / min to 75 L / min.

[0031] In step 1) of the present application, the carbon coating time is 60 min to 300 min. Alternatively, the carbon coating time is 60 min to 80 min, 80 min to 160 min, or 160 min to 300 min, etc. Preferably, the carbon coating time is 80 min to 160 min.

[0032] In step 1) of the present application, the gram capacity of the high-carbon material obtained is ≤1400 mAh / g. The mass ratio of the first silicon monoxide carbon-coated negative electrode material to the high-carbon material is (94-96):(6-4), i.e. 4% to 6% of high-carbon material is produced. The carbon content in the high-carbon material is greater than or equal to 18.5%, for example, 18.5% to 32.6%.

[0033] The first silicon monoxide carbon-coated negative electrode material meets the following conditions: gram capacity ≥1600 mAh / g; first efficiency ≥75.5%.

[0034] In the method for recycling high-carbon content silicon monoxide negative electrode material in industrial production provided by the present application, step 2) is to perform carbon burning treatment on the high-carbon material provided in step 1) to provide a carbon-burned material. Specifically:

[0035] In step 2) of the present application, the carbon-burning temperature is 300-500℃. Alternatively, the carbon-burning temperature can be 300-350℃, 350-450℃, 450-500℃, 300-400℃ or 400-500℃, etc. Preferably, the carbon-burning temperature is 350-450℃. Within the above carbon-burning temperature range, the temperature is favorable for the completion of carbon burning and does not excessively oxidize the material, so that the obtained carbon-burning material can obtain high gravimetric capacity and initial efficiency after further carbon-coating. Outside the carbon-burning temperature range of the present application, the gravimetric capacity and initial efficiency are significantly reduced, because the temperature is insufficient or leads to excessive oxidation of the product.

[0036] Further, the heating rate of the carbon burning is 5 min / ℃.

[0037] In step 2) of the present application, the carbon-burning time is 3-7h. Alternatively, the carbon-burning time can be 3-4h, 4-7h, 3-5h, 5-6h or 6-7h, etc. Preferably, the carbon-burning time is 5-6h. Within the above carbon-burning time range, the carbon-burning time can reduce the carbon content and does not excessively oxidize the material, so that the obtained carbon-burning material can obtain high gravimetric capacity and initial efficiency after further carbon-coating. Outside the carbon-burning time range of the present application, the gravimetric capacity and initial efficiency are significantly reduced, because the carbon-burning time is too short and the high-carbon material is not completely decarburized, or the carbon-burning time is too long and the material is excessively oxidized.

[0038] In step 2) of the present application, the carbon burning is carried out in a batch furnace without gas protection and in air. This advantage reduces resource waste and consumes oxygen in air.

[0039] In step 2) of the present application, the carbon content in the obtained carbon-burning material is reduced to below 1%, and can be as low as 0%.

[0040] In the method for recycling high-carbon silicon monoxide negative electrode material in industrial production provided by the present application, step 3) is carbon-coating the carbon-burning material provided in step 2) to provide a second silicon monoxide carbon-coated negative electrode material. Specifically:

[0041] In step 3) of the present application, the carbon-burning material is put into a coating furnace for carbon-coating.

[0042] In step 3) of the present application, the feeding speed of the carbon-burning material is 10-100 kg / h. Alternatively, the feeding speed of the carbon-burning material can be, for example, 10-40 kg / h, 40-60 kg / h or 60-100 kg / h, etc. Preferably, the feeding speed of the carbon-burning material can be, for example, 40-60 kg / h.

[0043] In step 3) of the present application, the temperature of the carbon coating is 850-1050℃. Alternatively, the temperature of the carbon coating is 850-900℃, 900-1000℃ or 1000-1050℃, etc. Preferably, the temperature of the carbon coating is 900-1000℃.

[0044] In step 3) of the present application, the gas for carbon coating is a hydrocarbon small molecule gas; wherein the hydrocarbon small molecule gas is selected from methane and / or acetylene. The flow rate of the gas source is 10-100 L / min. Alternatively, the flow rate of the gas source is 10-40 L / min, 40-75 L / min or 75-100 L / min, etc. Preferably, the flow rate of the gas source is 40-75 L / min.

[0045] In step 3) of the present application, the carbon coating time is 60-300 min. Alternatively, the carbon coating time is 60-80 min, 80-160 min or 160-300 min, etc. Preferably, the carbon coating time is 80-160 min.

[0046] In step 3) of the present application, the carbon content of the second silicon monoxide carbon-coated negative electrode material prepared is 3-8%. Alternatively, the carbon content of the second silicon monoxide carbon-coated negative electrode material may, for example, be 3-5%, 5-8%, 3-4%, 4-5%, 5-6%, 6-7% or 7-8%, etc.

[0047] In step 3) of the present application, the second silicon monoxide carbon-coated negative electrode material contains silicon dioxide. Alternatively, the content of silicon dioxide in the second silicon monoxide carbon-coated negative electrode material is less than 3%. Further alternatively, the content of silicon dioxide in the second silicon monoxide carbon-coated negative electrode material may, for example, be less than 2.5%, less than 2.0%, less than 1.5%, less than 1%, etc.

[0048] Silicon monoxide carbon-coated negative electrode material

[0049] The present application also provides a silicon monoxide carbon-coated negative electrode material prepared by the method for recycling and utilizing high-carbon-content silicon monoxide negative electrode material in industrial production provided in the first aspect of the present application. The silicon monoxide carbon-coated negative electrode material can achieve the specific capacity of the original silicon monoxide negative electrode material; at the same time, the low expansion coefficient and safety performance make its application range involve consumer electronics and electric vehicle fields.

[0050] Application

[0051] The present application also provides the application of the silicon monoxide carbon-coated negative electrode material, which can be applied in the consumer electronics and electric vehicle fields.

[0052] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application is specifically described below in conjunction with examples and drawings.

[0053] In the following examples, each of the reaction raw materials is a commercially available product unless otherwise specified.

[0054] Unless otherwise specified, the purity of each product of each embodiment of the present application is more than 98%.

[0055] Example 1

[0056] (1) 1500 kg of silicon suboxide (SiOx) material, DV(50): 7-8 μm, was continuously carbon-coated at a feeding speed of 50 kg / h, the coating temperature of this furnace was 900 ℃, the carbon source gas for coating was acetylene, the gas source flow rate was 55 L / min, and the coating time was 120 min.

[0057] After the carbon coating was completed, high-frequency infrared carbon and sulfur analyzer (detection means) was used for detection, and the proportion of high-carbon material was 4%-6%, the carbon content of the high-carbon material was 18.5%, and the specific capacity of the high-carbon material was 1376.68 mAh / g.

[0058] (2) 3 kg of high-carbon material with a carbon content of 18.5% was subjected to carbon burning treatment, the temperature rising rate was set to 5 min / ℃, the temperature was raised to 400 ℃, and the temperature was maintained for 6 h, the calcination was carried out in air without gas protection.

[0059] After testing, the carbon content of the carbon-burned material was 0.

[0060] (3) The carbon-burned material obtained in step (2) was subjected to carbon coating again, the feeding speed was 40 kg / h-60 kg / h, the carbon coating temperature was 900 ℃-1000 ℃, the hydrocarbon small molecule gas was selected from methane and / or acetylene, the gas source flow rate was 40 L / min-75 L / min, and the carbon coating time was 80 min-160 min. After detection, the carbon content of the carbon-coated product was 4.25%.

[0061] Example 2

[0062] The preparation process was basically the same as in Example 1, and the only difference was that the temperature in step (2) was adjusted to 300 ℃.

[0063] Example 3

[0064] The preparation process was basically the same as in Example 1, and the only difference was that the temperature in step (2) was adjusted to 500 ℃.

[0065] Comparative Example 1

[0066] The preparation process is basically the same as in Example 1, except that the temperature in step (2) is adjusted to 200°C.

[0067] Comparative Example 2

[0068] The preparation process is basically the same as in Example 1, except that the temperature in step (2) is adjusted to 600°C.

[0069] Example 4

[0070] The preparation process is basically the same as in Example 1, except that the holding time in step (2) is adjusted to 3h.

[0071] Example 5

[0072] The preparation process is basically the same as in Example 1, except that the holding time in step (2) is adjusted to 7h.

[0073] Comparative Example 3

[0074] The preparation process is basically the same as in Example 1, except that the holding time in step (2) is adjusted to 2h.

[0075] Comparative Example 4

[0076] The preparation process is basically the same as in Example 1, except that the holding time in step (2) is adjusted to 8h.

[0077] Example 6

[0078] The preparation process is basically the same as in Example 1, except that:

[0079] In step (2), 3kg of high-carbon material with a carbon content of 32.6% is subjected to carbon-burning treatment, with a temperature rising rate of 5min / °C, and the temperature is raised to 400°C and held for 6h, without gas protection, and calcination is performed in air.

[0080] Example 7

[0081] The preparation process is basically the same as in Example 1, except that:

[0082] In step (2), 3kg of high-carbon material with a carbon content of 29% is subjected to carbon-burning treatment, with a temperature rising rate of 5min / °C, and the temperature is raised to 400°C and held for 6h, without gas protection, and calcination is performed in air.

[0083] Comparative Example 5

[0084] The preparation process is basically the same as in Example 1, except that in step (2), 3kg of silicon monoxide raw material is subjected to heat treatment, and the heat-treated silicon monoxide obtained is selected.

[0085] Comparative Example 6

[0086] The preparation process is basically the same as that in Example 1, except that step (3) is removed.

[0087] Comparative Example 7

[0088] The preparation process is basically the same as that in Example 1, except that the carbonized material in step (2) is pickled with 5% HF for 12 h, then washed with water three times, and dried at 100°C under vacuum.

[0089] Table 1: Gravimetric capacity and initial efficiency of different carbon contents

[0090] Carbon content (%) Capacity (mAh / g) Initial efficiency (%) 3～5 ≥1600 ≥75.5 18.5 1376.68 75.49 29 1280.54 75.74 32.6 1146.21 75.89

[0091] Table 2: Gravimetric capacity and initial efficiency of experimental examples and comparative examples

[0092]

[0093]

[0094] From Table 2, it can be seen that:

[0095] From Examples 1-3 and Comparative Examples 1-2, it can be seen that when the carbonization temperature is in the range of 300-500°C, the gravimetric capacity is >1600 mAh / g, and the initial efficiency is >75.5%, which can meet the electrochemical performance requirements of silicon-oxygen negative electrode materials. When the carbonization temperature is 200°C or 600°C, the gravimetric capacity is <1600 mAh / g, and the initial efficiency is <75.5%, which cannot meet the electrochemical performance requirements of silicon-oxygen negative electrode materials.

[0096] From Examples 1, 4-5 and Comparative Examples 3-4, it can be seen that when the carbonization time is in the range of 3-7 h, the gravimetric capacity is >1600 mAh / g, and the initial efficiency is >75.5%, which can meet the electrochemical performance requirements of silicon-oxygen negative electrode materials. When the carbonization time is 2 h or 8 h, the gravimetric capacity is <1600 mAh / g, and the initial efficiency is <75.5%, which cannot meet the electrochemical performance requirements of silicon-oxygen negative electrode materials.

[0097] From Examples 1, 6 and 7, it can be seen that when the carbonized material with different carbon contents is treated, the gravimetric capacity is >1600 mAh / g, and the initial efficiency is >75.5%, which can meet the electrochemical performance requirements of silicon-oxygen negative electrode materials.

[0098] From Example 1 and Comparative Example 5, it can be seen that when the silicon monoxide raw material is heat-treated in Comparative Example 5, the gravimetric capacity is <1600 mAh / g, and the initial efficiency is <75.5%, which cannot meet the electrochemical performance requirements of silicon-oxygen negative electrode materials.

[0099] Combining Example 1 with Comparative Example 6, the Comparative Example 6 does not re-carbonize the calcined material, the gram capacity is <1600 mAh / g, the initial efficiency is <75.5%, and the electrochemical performance of the silicon-oxygen negative electrode material cannot meet the requirements.

[0100] Combining Example 1 with Comparative Example 7, the Comparative Example 7 acid-washes the calcined material, the gram capacity is <1600 mAh / g, the initial efficiency is <75.5%, and the electrochemical performance of the silicon-oxygen negative electrode material cannot meet the requirements, and the 100-cycle capacity retention rate is not as good as that of Example 1.

[0101] The products prepared in each of the examples and comparative examples are used as negative electrode materials to prepare button cells, and the specific steps are as follows: the silicon-oxygen composite material, the conductive agent SP, the dispersing agent CMC, and the binder AONE are mixed in a mass ratio of 70:15:5:10, and water is used as a solvent to prepare a negative electrode slurry; the negative electrode slurry is coated on a copper foil, and a lithium sheet is used as a counter electrode and a Celgard 2400 microporous polypropylene membrane is used as a separator to prepare a button cell.

[0102] The button cell prepared is subjected to charge-discharge cycling, and the charge-discharge conditions are as follows: the charge-discharge cutoff voltage is 0.005-1.5 V, the discharge rate is first 0.1 C to 0.005 V, then 0.02 C to 0.005 V to fully discharge, the charge rate is 0.1 C to 1.5 V, and the reversible capacity and the initial coulombic efficiency of the button cell are detected.

[0103] The battery cycle performance is tested on a Blue Battery Test System CT2001A device. At 25°C, the charge-discharge cycle characteristics of the button cell are detected using the above-mentioned Blue Test Cabinet. First, discharge at 0.1 C to 0.005 V, then discharge at 0.08 C to 0.001 V, discharge at 0.05 C to 0.001 V, discharge at 0.02 C to 0.001 V, and stand for 10 min. Then charge at 0.1 C to 1.5 V and stand for 10 min. Record the charge-discharge capacity after the first cycle, and calculate the initial coulombic efficiency. Cycle 100 times in the above-mentioned manner, record the charge-discharge capacity after 100 times, and calculate the capacity retention rate after 100 cycles.

[0104] The above-mentioned embodiments are preferred cases of the present application, and do not limit the protection scope of the present application.

[0105] The applicant declares that the present application is illustrated by the above-mentioned examples to recover and utilize the high-carbon-content silicon monoxide negative electrode material in industrial production, but the present application is not limited to the above-mentioned examples, i.e., it does not mean that the present application must rely on the above-mentioned examples to be implemented. It should be understood by those skilled in the art that any improvement on the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific modes, etc., all fall within the protection scope and disclosure scope of the present application.

[0106] The above embodiments are preferred cases of the present application and are not intended to limit the protection scope of the present application. However, the present application is not limited to the specific details in the above embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0107] In addition, it should be noted that various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, various possible combinations are not described again in the present application.

Claims

1. A method for recycling high-carbon-content silicon monoxide negative electrode material in industrial production, characterized in that, The method comprises the following steps: 1) carbon-coating silicon monoxide material to provide a first silicon monoxide-carbon negative electrode material and high-carbon material; 2) calcining the high-carbon material provided in step 1) to provide calcined carbon material; 3) carbon-coating the calcined carbon material provided in step 2) to provide a second silicon monoxide-carbon negative electrode material; In step 2), the calcining temperature is 300-500°C, and the calcining time is 3-7 hours.

2. The method for recycling high-carbon-content silicon monoxide negative electrode material in industrial production according to claim 1, characterized in that, One or more of the following features are also included: A1) the Dv50 of the silicon monoxide material is 7-8 μm; A2) the silicon monoxide material is fed into a coating furnace for carbon-coating; A3) the feeding speed of the silicon monoxide material is 10-100 kg / h; A4) the carbon-coating temperature is 850-1050°C; A5) the carbon-coating gas is a hydrocarbon small molecule gas; the gas source flow rate is 10-100 L / min; A6) the carbon-coating time is 60-300 minutes.

3. The method for recycling high-carbon-content silicon monoxide negative electrode material in industrial production according to claim 2, characterized in that, One or more of the following features are also included: A31) in A3), the feeding speed is 40-60 kg / h; A41) in A4), the carbon-coating temperature is 900-1000°C; A51) in A5), the hydrocarbon small molecule gas is selected from methane and / or acetylene; the gas source flow rate is 40-75 L / min; A61) in A6), the carbon-coating time is 80-160 minutes.

4. The method for recycling high-carbon-content silicon monoxide negative electrode material in industrial production according to claim 1, characterized in that, In step 1), any one or more of the following features are also included: B1) in step 1), the specific capacity of the high-carbon material is ≤1400 mAh / g; B2) in step 1), the mass ratio of the first silicon monoxide-carbon negative electrode material to high-carbon material is (94-96):(6-4).

5. The method for recycling high-carbon-content silicon monoxide negative electrode material in industrial production according to claim 1, characterized in that, In step 2), any one or more of the following features are also included: C1) in step 2), the calcining is performed in a batch furnace; C2) in step 2), the calcining is performed in air without gas protection; C3) in step 2), the carbon content in the calcined carbon material is reduced to ≤1%.

6. The method for recycling high-carbon-content silicon monoxide negative electrode material in industrial production according to claim 1, characterized in that, Any one or more of the following features are also included: C11) the calcining temperature is 350-450°C; C12) the heating rate of the calcining is 5 min / °C; C21) the calcining time is 5-6 hours.

7. The method for recycling high-carbon-content silicon monoxide negative electrode material in industrial production according to claim 1, characterized in that, In step 3), one or more of the following features are also included: D1) in step 3), the calcined carbon material is fed into a coating furnace for carbon-coating; D2) in step 3), the feeding speed of the calcined carbon material is 10-100 kg / h; D3) in step 3), the carbon-coating temperature is 850-1050°C; D4) in step 3), the carbon-coating gas is a hydrocarbon small molecule gas; the gas source flow rate is 10-100 L / min; D5) in step 3), the carbon-coating time is 60-300 minutes; D6) in step 3), the carbon content of the second silicon monoxide-carbon negative electrode material is 3-8%; D7) in step 3), the second silicon monoxide-carbon negative electrode material contains silicon dioxide.

8. The method for recycling high-carbon-content silicon monoxide negative electrode material in industrial production according to claim 7, characterized in that, In step 3), any one or more of the following features are also included: D21) In D2), the feeding speed is 40 kg / h to 60 kg / h; D31) In D3), the temperature of the carbon-coating is 900 °C to 1000 °C; D41) In D4), the hydrocarbon small molecule gas is selected from methane and / or acetylene; the gas source flow rate is 40 L / min to 75 L / min; D51) In D5), the time of the carbon-coating is 80 min to 160 min; D71) In D7), the content of silicon dioxide in the second silicon monoxide-coated carbon negative electrode material is less than 3%.

9. A silicon suboxide carbon-coated negative electrode material, characterized by The silicon monoxide-coated carbon negative electrode material is prepared by the method according to any one of claims 1 to 8.

10. Use of the silicon monoxide-coated carbon negative electrode material according to claim 9 in the field of consumer electronics and electric vehicles.

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