A silicon-oxygen anode material, its preparation method and uses

Abstract

The present invention provides a silicon-oxygen negative electrode material, a preparation method thereof, and uses thereof. The preparation method includes: mixing a silicon-oxygen material with nano lithium metal particles under an inert atmosphere, and successively performing normal temperature fluidization, primary temperature-raising fluidization, secondary temperature-raising fluidization, and tertiary temperature-raising fluidization. Carbon coating is performed during the secondary temperature-raising fluidization process, and the entire fluidization process is carried out under an inert atmosphere; thus obtaining the silicon-oxygen negative electrode material. By means of the fluidization method and combined with carbon coating, the present invention effectively controls the doping process of lithium metal and effectively controls the growth of the silicon crystal grain size inside the silicon-oxygen particles, thereby obtaining a silicon-oxygen negative electrode material with high initial efficiency and long cycle life.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium-ion batteries, and relates to a silicon-oxygen anode material, a preparation method thereof, and uses thereof. Background Art

[0002] Lithium-ion batteries have a wide range of applications in the new energy field. As the most widely used anode material in lithium-ion batteries, graphite has a stable voltage platform and long cycle stability characteristics. However, the theoretical capacity of the material is only 372 mAh / g, which cannot meet the needs of humans for high-energy density energy storage. Silicon-based anode materials have become one of the most promising anode materials in the future due to their ultra-high specific capacity. However, the volume expansion of pure silicon materials is relatively large, and silicon-oxygen materials can alleviate the volume expansion problem of the materials to a certain extent due to their special structural characteristics. The main structure of silicon-oxygen materials is silicon nanocrystals dispersed in silicon dioxide. During the first charge and discharge process, silicon dioxide will consume lithium salts, resulting in a decrease in the initial efficiency of the material. Therefore, how to improve the initial efficiency of silicon-oxygen materials is crucial. The technology of pre-doping lithium can, in the process of pretreatment, pre-react lithium with silicon dioxide materials in a pre-lithiation manner to form lithium silicate salts, thereby weakening the irreversible lithium salt consumption during the initial discharge process in the battery cycle. However, the doping of lithium is difficult, mainly because lithium metal has poor air stability and is easily oxidized in the air to form lithium oxide, lithium carbonate, etc.

[0003] High-initial-efficiency silicon-oxygen materials have important application prospects. However, the doping process of silicon-oxygen materials using lithium metal will cause local overheating of the materials, resulting in uneven doping inside the silicon-oxygen, an increase in the size of large silicon grains inside the silicon-oxygen particles, and a deterioration of the cycle performance of the materials.

[0004] CN106848270A discloses a lithium-supplementing slurry for an anode, an anode, and a lithium secondary battery. The lithium-supplementing slurry of the invention includes metallic lithium powder and a prepolymer. The prepolymer is used as a binder for lithium supplementation. Its production process is simple and the use cost is low; the lithium-supplementing method using the prepolymer is simple in operation, low in cost, and easy to control the amount of lithium supplementation. However, during the use of the battery, conditions such as ultraviolet light irradiation or heating are required to cause the prepolymer to undergo a polymerization reaction to play the role of the prepolymer, and the operation is complex. The first charge and discharge efficiency and discharge capacity of the lithium-ion battery after lithium supplementation need to be further improved.

[0005] CN102916165A discloses a method for supplementing lithium to a negative electrode sheet of a lithium-ion battery. By spraying or dropping an organolithium solution on the surface of the negative electrode sheet, lithium ions in the organolithium solution are reduced to obtain metallic lithium, thereby realizing negative electrode lithium supplementation. Organolithium reagents are relatively expensive, and substances with stronger reducibility than metallic lithium need to be added to reduce lithium ions to metallic lithium, increasing the cost, and the lithium-supplementing process route is complex.

[0006] CN104993098A discloses a lithium - supplemented negative electrode sheet, its preparation method, a lithium - ion supercapacitor, and a lithium - ion battery, belonging to the technical field of energy storage devices. Lithium powder is used as the lithium source for supplementing lithium in the negative electrode. The lithium powder particles are small, with a particle size in the micron range. During operation, there is a phenomenon that the particles fly everywhere, which requires a very strict operating environment and poses a safety hazard.

[0007] Therefore, how to improve the electrochemical performance of the silicon - oxygen negative electrode material by doping lithium is a technical problem to be urgently solved. Summary of the Invention

[0008] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a silicon - oxygen negative electrode material, its preparation method and uses. By the fluidization method and combined with carbon coating, the doping process of lithium metal is effectively controlled, and the growth of the silicon crystal grain size inside the silicon - oxygen particles is effectively controlled, thereby obtaining a silicon - oxygen negative electrode material with high initial efficiency and long cycle life.

[0009] To achieve this purpose, the present invention adopts the following technical solutions:

[0010] In the first aspect, the present invention provides a preparation method of a silicon - oxygen negative electrode material, and the preparation method includes:

[0011] Mix the silicon - oxygen material with nano - lithium metal particles in an inert atmosphere, and successively carry out normal - temperature fluidization, first - stage temperature - rising fluidization, second - stage temperature - rising fluidization, and third - stage temperature - rising fluidization. Carbon coating is carried out during the second - stage temperature - rising fluidization process, and the whole process of fluidization is carried out in an inert atmosphere; thus obtaining the silicon - oxygen negative electrode material.

[0012] The normal temperature in the normal - temperature fluidization referred to in the present invention is in the range of 20 - 40 °C, such as 20 °C, 25 °C, 30 °C, 35 °C or 40 °C, etc.

[0013] By the fluidization method of the present invention, the doping process of lithium metal is effectively controlled, and the growth of the silicon crystal grain size inside the silicon - oxygen particles is effectively controlled, thereby obtaining a silicon - oxygen negative electrode material with high initial efficiency and long cycle life.

[0014] In the present invention, through normal-temperature fluidization, metal lithium particles with nano-sized particles are in continuous motion and constantly contact with silicon-oxygen particles, thereby ensuring that the lithium metal particles are effectively and uniformly adsorbed on the surface of the silicon-oxygen particles through electrostatic adsorption. Through primary temperature-raising fluidization, the nano-lithium metal particles adsorbed on the surface of the silicon-oxygen particles will gradually melt, forming a thin lithium metal film layer structure on the surface of the silicon-oxygen particles, increasing the contact area between the lithium metal and the silicon-oxygen particles. On this basis, while further raising the temperature for fluidization, carbon coating is carried out. In this process, the lithium metal and the silicon-oxygen particle materials can effectively promote the deposition process of the carbon layer. Such a catalytic process can fully ensure the effective deposition of the carbon layer and obtain a uniform carbon coating layer. Finally, the temperature is continuously raised for fluidization. In this process, the lithium metal particles and the silicon-oxygen materials are uniformly doped. Since the contact between the metal lithium and the silicon-oxygen particles is in a uniform state, it can effectively prevent the local overheating problem in the reaction between the lithium metal and the silicon-oxygen particles, effectively realizing the doping of the lithium metal. Moreover, the effective protection of the carbon layer material can effectively ensure the stability of the particles in the air, and finally obtain a silicon-oxygen negative electrode material with high initial efficiency, high capacity and long cycle life.

[0015] In the present invention, the main structure of the silicon-oxygen material is that silicon nanocrystals are dispersed in silicon dioxide. The silicon nanocrystals are obtained by disproportionation of silicon monoxide material during the heating process of the silicon-oxygen material. The stronger the thermal effect, the more severe the disproportionation effect, which will lead to a larger grain size of the silicon nanoparticles.

[0016] In the present invention, if the median particle size of the lithium metal particles is not in the nano range, it will cause incomplete reaction of the large-particle lithium metal particles during the later material reaction process, resulting in waste of the lithium metal material. At the same time, the use of nano-lithium metal can ensure the controllability of the thermal reaction during the later disproportionation process of the lithium metal and the silicon-oxygen material, and will not cause local overheating phenomena, thereby ensuring the effectiveness of the doping of the silicon-oxygen material.

[0017] In the present invention, both the mixing process and the fluidization process should be carried out in an inert atmosphere, such as a helium atmosphere, a neon atmosphere, an argon atmosphere, a krypton atmosphere or a xenon atmosphere, etc. If it is a non-inert atmosphere, such as a nitrogen atmosphere, it will react with lithium and cause material consumption.

[0018] Preferably, the median particle size of the silicon-oxygen material is 3-15 μm, such as 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or 15 μm, etc.

[0019] Preferably, the median particle size of the nano-lithium metal particles is 5-50 nm, such as 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm or 50 nm, etc.

[0020] In the present invention, if the median particle size of the nano lithium metal particles is too large, it is not conducive to the slow doping of lithium metal. Otherwise, the reaction rate of the material will be too fast, resulting in the growth of silicon grains.

[0021] Preferably, the mass ratio of the silicon-oxygen material to the nano lithium metal particles is 100:(1-20), such as 100:1, 100:5, 100:10, 100:15 or 100:20, etc.

[0022] In the present invention, if there are too many nano lithium metal particles, it will cause excessive reaction of lithium metal, resulting in violent doping reaction of the silicon-oxygen material. At the same time, the price of lithium metal material is relatively expensive, and excessive addition of lithium metal will lead to too much residual unreacted lithium metal.

[0023] Preferably, the time of normal temperature fluidization is 1-5 h, such as 1 h, 2 h, 3 h, 4 h or 5 h, etc.

[0024] Preferably, the temperature of the first-stage temperature-raising fluidization is 150-300 °C, such as 150 °C, 200 °C, 250 °C or 300 °C, etc.

[0025] Preferably, the time of the first-stage temperature-raising fluidization is 1-5 h, such as 1 h, 2 h, 3 h, 4 h or 5 h, etc.

[0026] Preferably, the temperature of the second-stage temperature-raising fluidization is 500-800 °C, such as 500 °C, 550 °C, 600 °C, 650 °C, 700 °C, 750 °C or 800 °C, etc.

[0027] Preferably, the time of the second-stage temperature-raising fluidization is 1-10 h, such as 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h, etc.

[0028] Preferably, based on the mass of the silicon-oxygen material being 100%, the mass of the carbon coating layer after carbon coating is 3-5%, such as 3%, 3.5%, 4%, 4.5% or 5%, etc.

[0029] Preferably, the carbon coating in the second-stage temperature-raising fluidization process includes gas-phase carbon coating and / or liquid-phase carbon coating.

[0030] Preferably, the carbon source in the gas-phase carbon coating includes any one or a combination of at least two of acetylene, ethylene, propylene, propane, ethane or methane.

[0031] Preferably, the carbon source in the liquid-phase carbon coating includes any one or a combination of at least two of benzene, toluene or acetonitrile.

[0032] Preferably, the temperature of the three-stage temperature-raising fluidization is 900-1200 °C, such as 900 °C, 950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C or 1200 °C, etc.

[0033] In the present invention, if the temperature of the three-stage temperature-raising fluidization is too low, effective doping of lithium metal and silicon-oxygen material cannot be achieved, while if the temperature is too high, the doping reaction will be too intense, resulting in a decline in the cycling performance of the material.

[0034] Preferably, the time of the three-stage temperature-raising fluidization is 1-5 h, such as 1 h, 2 h, 3 h, 4 h or 5 h, etc.

[0035] Preferably, the product after the three-stage temperature-raising fluidization is washed with water and / or pickled with acid to remove a small amount of unreacted lithium or lithium oxide substances.

[0036] As a preferred technical solution, the preparation method includes:

[0037] Mix the silicon-oxygen material and nano lithium metal in an inert atmosphere at a mass ratio of 100:(1-20), and successively carry out normal-temperature fluidization for 1-5 h, first heat up to 150-300 °C for fluidization for 1-5 h, second heat up to 500-800 °C for fluidization for 1-10 h, and third heat up to 900-1200 °C for fluidization for 1-5 h. Carbon coating and pickling are carried out during the second-stage temperature-raising fluidization process to obtain the silicon-oxygen negative electrode material;

[0038] Among them, the whole process of fluidization is carried out in an inert atmosphere. The median particle size of the silicon-oxygen material is 3-15 μm; the median particle size of the lithium metal is 5-5 nm; based on the mass of the silicon-oxygen material being 100%, the mass of the carbon coating layer after carbon coating is 3-5%.

[0039] In the second aspect, the present invention provides a silicon-oxygen negative electrode material, which is prepared by the preparation method of the silicon-oxygen negative electrode material as described in the first aspect. The silicon-oxygen negative electrode material includes a core and a carbon coating layer coated on the surface of the core, and the core is a silicon-oxygen material doped with lithium metal.

[0040] In the third aspect, the present invention provides a lithium-ion battery, which includes the silicon-oxygen negative electrode material as described in the third aspect.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] By means of the segmented fluidization method and in combination with carbon coating, the present invention effectively controls the doping process of lithium metal and effectively controls the growth of the silicon crystal grain size inside the silicon-oxygen particles, thereby obtaining a silicon-oxygen negative electrode material with high initial efficiency and long cycle life. In the silicon-oxygen negative electrode material provided by the present invention, the size of the silicon nanocrystals is within 5.5 - 8.8 nm, the discharge specific capacity at 0.1C can reach more than 1360 mAh / g, the initial efficiency can reach more than 85%, and the capacity retention rate can reach more than 89.3% after 100 cycles at 1C. Detailed implementation manners

[0043] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0044] Example 1

[0045] This example provides a silicon-oxygen negative electrode material, which includes a core and a carbon coating layer coated on the surface of the core, and the core is a silicon-oxygen material doped with lithium metal.

[0046] The preparation method of the silicon-oxygen negative electrode material is as follows:

[0047] Mix silicon-oxygen material with a median particle size of 5 μm and nano lithium metal with a median particle size of 10 nm in a helium atmosphere at a mass ratio of 100:5. Transfer the mixture to a fluidized bed device through a material transfer tank, and then in an argon atmosphere, perform fluidization at room temperature (25°C) for 4 h, then heat the fluidized bed device to 200°C for fluidization for 2 h, and then continue to heat the fluidized bed device to 800°C for fluidization for 6 h. During this period, introduce methane for gas-phase carbon coating. Finally, further heat the fluidized bed device to 1000°C for fluidization for 3 h, and perform pickling with 0.1 mol / L hydrochloric acid solution to obtain the silicon-oxygen negative electrode material;

[0048] Based on the mass of the silicon-oxygen material being 100%, the mass of the carbon coating layer after carbon coating is 3%.

[0049] Example 2

[0050] This example provides a silicon-oxygen negative electrode material, which includes a core and a carbon coating layer coated on the surface of the core, and the core is a silicon-oxygen material doped with lithium metal.

[0051] The preparation method of the silicon-oxygen negative electrode material is as follows:

[0052] Mix silicon oxide material with a median particle size of 8 μm and nano lithium metal with a median particle size of 50 nm in a helium atmosphere at a mass ratio of 100:20. Transfer the mixture to a fluidized bed device through a material transfer tank. Then, in a neon atmosphere, perform fluidization at room temperature (30 °C) for 1 h, then heat the fluidization device to 300 °C for fluidization for 1 h, and then continuously heat the fluidization device to 750 °C for fluidization for 10 h. During this period, add toluene for liquid-phase carbon coating. Finally, further heat the fluidization device to 900 °C for fluidization for 1 h, and perform pickling with a 0.5 mol / L hydrochloric acid solution to obtain the silicon oxide negative electrode material;

[0053] Based on the mass of the silicon oxide material being 100%, the mass of the carbon coating layer after carbon coating is 5%.

[0054] Example 3

[0055] This example provides a silicon oxide negative electrode material, which includes a core and a carbon coating layer coated on the surface of the core. The core is a silicon oxide material doped with lithium metal.

[0056] The preparation method of the silicon oxide negative electrode material is as follows:

[0057] Mix silicon oxide material with a median particle size of 3 μm and nano lithium metal with a median particle size of 5 nm in a helium atmosphere at a mass ratio of 100:1. Transfer the mixture to a fluidized bed device through a material transfer tank. Then, in an argon atmosphere, perform fluidization at room temperature (35 °C) for 5 h, then heat the fluidization device to 150 °C for fluidization for 5 h, and then continuously heat the fluidization device to 650 °C for fluidization for 1 h. During this period, introduce acetylene for gas-phase carbon coating. Finally, further heat the fluidization device to 1100 °C for fluidization for 5 h, and perform water washing to obtain the silicon oxide negative electrode material;

[0058] Based on the mass of the silicon oxide material being 100%, the mass of the carbon coating layer after carbon coating is 4%.

[0059] Example 4

[0060] The difference between this example and Example 1 is that the median particle size of the nano lithium metal particles in this example is 100 nm.

[0061] The remaining preparation methods and parameters are the same as those in Example 1.

[0062] Example 5

[0063] The difference between this example and Example 1 is that the mass ratio of the silicon oxide material to the nano lithium metal particles in this example is 100:30.

[0064] The remaining preparation methods and parameters are the same as those in Example 1.

[0065] Comparative Example 1

[0066] The difference between this comparative example and Example 1 is that in this example, there is no first temperature-raising fluidization. After normal-temperature temperature-raising fluidization, the second temperature-raising fluidization is directly carried out.

[0067] The remaining preparation methods and parameters are the same as those in Example 1.

[0068] Comparative Example 2

[0069] The difference between this comparative example and Example 1 is that this comparative example does not carry out the second temperature-raising fluidization process, that is, the carbon coating process is not carried out.

[0070] The remaining preparation methods and parameters remain the same.

[0071] Comparative Example 3

[0072] The difference between this comparative example and Example 1 is that the median particle size of the lithium metal particles in this comparative example is 1 μm.

[0073] The remaining preparation methods and parameters remain the same.

[0074] Experimental tests:

[0075] (1) Test of material capacity and initial efficiency: The negative electrode materials obtained in Examples 1-5 and Comparative Examples 1-3 were mixed evenly with SBR, CMC, and SP in a ratio of 85:3.2:1.8:10, coated on a copper foil, and prepared into a pole piece with a diameter of 12 mm through drying, rolling, and cutting. It was assembled into a button cell with a lithium metal sheet. The electrolyte was a conventional lithium-ion battery electrolyte, and the separator was a PP separator. The electrochemical performance test was carried out for conventional battery charge and discharge on a Blue Electric Tester. The capacity of the negative electrode material was the mass specific capacity of the half-cell de-lithiation measured at a rate of 0.1C.

[0076] (2) The test scheme for the cycle performance of the material is as follows: First, the obtained negative electrode material was mixed with a commercial graphite negative electrode material with a capacity of 350 mAh / g to form a silicon oxide / graphite composite negative electrode material with a capacity of 500 mAh / g. Subsequently, this composite material was mixed evenly with SBR, CMC, and SP in a ratio of 94.5:2.5:1.5:1.5, coated on a copper foil, and prepared into a pole piece with a diameter of 12 mm through drying, rolling, and cutting. It was assembled into a button cell with a lithium metal sheet. The electrolyte was a conventional lithium-ion battery electrolyte, and the separator was a PP separator. The electrochemical performance test was carried out for conventional battery charge and discharge on a Blue Electric Tester.

[0077] (3) Measurement of the size of silicon nanocrystals: The structure of the material was analyzed using an XRD device, and then the grain size of the silicon particles in the material was calculated using the Scherrer formula. The instrument used in this experiment was a DX2700B diffractometer with a Cu target Kα radiation source and a wavelength of 0.154056 nm.

[0078] The results of the above tests are all shown in Table 1.

[0079] Table 1

[0080]

[0081]

[0082] From the data results of Example 1 and Example 4, it can be seen that if the median particle size of the nano lithium metal particles is too large, it will lead to insufficient reaction of the lithium metal and affect the doping effect of the material, resulting in a lower initial efficiency of the material and poor cycling performance of the material.

[0083] From the data results of Example 1 and Example 5, it can be seen that although an excessive amount of nano lithium metal particles can improve the initial efficiency of the material, too much lithium metal will lead to a weakened doping effect of the material, thus affecting the cycling performance of the material.

[0084] From the data results of Example 1 and Comparative Example 1, it can be seen that if the one-time temperature-raising fluidization process is not carried out and the carbon coating is directly carried out by the secondary temperature-raising fluidization after the temperature is raised from room temperature to fluidization, it will seriously affect the doping effect of the material and lead to a poor doping effect of the material.

[0085] From the data results of Example 1 and Comparative Example 2, it can be seen that if carbon coating is not carried out, it will affect the lithium doping effect of the material, resulting in a violent doping reaction and affecting the cycling performance of the material.

[0086] From the data results of Example 1 and Comparative Example 3, it can be seen that it is difficult to achieve effective doping of lithium metal when the lithium metal particles are within the non-nano level range.

[0087] Through the method of segmented fluidization and combined with carbon coating, the present invention effectively controls the doping process of lithium metal and effectively controls the growth of the silicon crystal grains inside the silicon-oxygen particles, thereby obtaining a silicon-oxygen negative electrode material with high initial efficiency and long cycle life. For the battery provided by the present invention, the size of the silicon nanocrystals in the silicon-oxygen negative electrode material is within 5.5 - 8.8 nm, the discharge specific capacity at 0.1C can reach more than 1360 mAh / g, the initial efficiency can reach more than 85%, and the capacity retention rate can reach more than 89.3% after 100 cycles at 1C.

[0088] The specific embodiments described above further elaborate on the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a silicon-oxygen anode material, characterized in that, The preparation method includes: Mixing a silicon-oxygen material with nano lithium metal particles in an inert atmosphere, and successively performing normal-temperature fluidization, first-stage temperature-raising fluidization, second-stage temperature-raising fluidization, and third-stage temperature-raising fluidization. Carbon coating is performed during the second-stage temperature-raising fluidization process, and the entire fluidization process is carried out in an inert atmosphere; obtaining the silicon-oxygen negative electrode material; The median particle size of the nano lithium metal particles is 5 - 50 nm; The temperature of the first-stage temperature-raising fluidization is 150 - 300 °C; the time of the first-stage temperature-raising fluidization is 1 - 5 h; The temperature of the second-stage temperature-raising fluidization is 500 - 800 °C; the time of the second-stage temperature-raising fluidization is 1 - 10 h; The temperature of the third-stage temperature-raising fluidization is 900 - 1200 °C; the time of the third-stage temperature-raising fluidization is 1 - 5 h.

2. The preparation method of the silicon-oxygen negative electrode material according to claim 1, characterized in that, The median particle size of the silicon-oxygen material is 3 - 15 μm.

3. The preparation method of the silicon-oxygen negative electrode material according to claim 1, wherein, The mass ratio of the silicon-oxygen material to the nano lithium metal particles is 100:(1 - 20).

4. The preparation method of the silicon-oxygen anode material according to claim 1, characterized in that, The time of the normal-temperature fluidization is 1 - 5 h.

5. The preparation method of the silicon-oxygen negative electrode material according to claim 1, characterized in that, Based on the mass of the silicon-oxygen material being 100%, the mass of the carbon coating layer after carbon coating is 3 - 5%.

6. The preparation method of the silicon-oxygen negative electrode material according to claim 1, wherein, The carbon coating during the second-stage temperature-raising fluidization process includes gas-phase carbon coating and / or liquid-phase carbon coating.

7. The preparation method of the silicon-oxygen anode material according to claim 6, characterized in that, The carbon source in the gas-phase carbon coating includes any one or a combination of at least two of acetylene, ethylene, propylene, propane, ethane, or methane.

8. The preparation method of the silicon-oxygen anode material according to claim 6, characterized in that, The carbon source in the liquid-phase carbon coating includes any one or a combination of at least two of benzene, toluene, or acetonitrile.

9. The preparation method of the silicon-oxygen negative electrode material according to claim 1, wherein, The preparation method further includes washing and / or pickling the product after the third-stage temperature-raising fluidization.

10. The preparation method of the silicon-oxygen negative electrode material according to claim 1, characterized in that, The preparation method includes: Mixing a silicon-oxygen material with nano lithium metal in an inert atmosphere at a mass ratio of 100:(1 - 20), successively performing normal-temperature fluidization for 1 - 5 h, first-stage temperature-raising to 150 - 300 °C and fluidizing for 1 - 5 h, second-stage temperature-raising to 500 - 800 °C and fluidizing for 1 - 10 h, third-stage temperature-raising to 900 - 1200 °C and fluidizing for 1 - 5 h. Carbon coating is performed during the second-stage temperature-raising fluidization process, and pickling is carried out to obtain the silicon-oxygen negative electrode material; Wherein, the entire fluidization process is carried out in an inert atmosphere, the median particle size of the silicon-oxygen material is 3 - 15 μm; the median particle size of the lithium metal is 5 - 50 nm; based on the mass of the silicon-oxygen material being 100%, the mass of the carbon coating layer after carbon coating is 3 - 5%.

11. A silicon-oxygen anode material, characterized in that, The silicon-oxygen negative electrode material is prepared by the preparation method of the silicon-oxygen negative electrode material according to any one of claims 1 - 10. The silicon-oxygen negative electrode material includes a core and a carbon coating layer coated on the surface of the core, and the core is a silicon-oxygen material doped with lithium metal.

12. A lithium-ion battery, characterized in that, The lithium-ion battery includes the silicon-oxygen negative electrode material according to claim 11.

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