A preparation method of aerogel spherical porous carbon, a preparation method of aerogel spherical silicon-carbon negative electrode material and a battery

Abstract

The application provides a preparation method of aerogel spherical porous carbon, a preparation method of aerogel spherical silicon-carbon negative electrode material and a battery. The aerogel microsphere porous carbon is prepared through a precursor synthesis step, a solvent replacement step, a drying and dehydration step, an alkali activation pore-forming step, a gas-phase deashing step and a physical activation step, and the aerogel microsphere porous carbon is further subjected to a silicon gas-phase deposition step and a carbon gas-phase coating step to prepare the aerogel spherical silicon-carbon negative electrode material, and the battery is prepared from the aerogel spherical silicon-carbon negative electrode material. The porous carbon prepared in the application has high pore volume, suitable and uniform pore size, regular spherical shape, low ash content, suitable and concentrated particle size distribution and high single-particle strength. The negative electrode material prepared in the application has lower resistivity, higher capacity, longer cycle life and stronger limiting capacity for internal silicon lithium intercalation expansion. The battery prepared in the application has higher discharge capacity, charging capacity and initial efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of biomass refining comprehensive utilization, and particularly relates to a preparation method of aerogel spherical porous carbon, a preparation method of aerogel spherical silicon-carbon negative electrode material and a battery. BACKGROUND

[0002] The theoretical capacity of a lithium ion battery graphite negative electrode is 375 mAh / g, and the high lithium intercalation capacity of silicon can meet the requirements of future high-capacity lithium battery negative electrodes. At present, most new silicon-carbon negative electrode materials use porous carbon as a substrate, and perform gas phase deposition in a silicon source-containing atmosphere to deposit nano-silicon into the porous carbon channels, and then perform gas phase coating in a carbon source-containing atmosphere to wrap a carbon layer on the surface of the material, so that the obtained silicon-carbon composite material can be used as a battery negative electrode material, achieving high capacity and long cycle life, and effectively improving the high expansion and low rate of the silicon-based negative electrode material.

[0003] On the one hand, the pore structure of the porous carbon needs to have good adsorption capacity for the silicon source gas to ensure that the reaction process of cracking the silicon source gas into nano-silicon occurs inside the porous carbon channels, which puts high requirements on the structural parameters of the porous carbon. If the structure of the porous carbon is not ideal, the silicon will be deposited on the surface of the material, resulting in floating silicon, and causing poor processability and cycle life of the material. On the other hand, the silicon source-containing gas needs to have sufficient gas-solid contact with the porous carbon, which has high requirements on the flowability of the porous carbon material. If the flowability of the material is poor, it is easy to agglomerate and clog in the equipment, resulting in uneven reaction during the silicon gas phase deposition and carbon gas phase coating, and poor product performance.

[0004] At present, coconut shell carbon, resin and the like are mostly used as precursors for the preparation of porous carbon, and the activation methods include steam activation, CO2 activation and alkali activation. The equipment used during activation includes roller kiln, rotary kiln and the like. The porous carbon prepared by different processes has different disadvantages. For example, the porous carbon prepared from coconut shell carbon has low structural strength and poor consistency of pore structure, and the new type of silicon-carbon negative electrode prepared therefrom has high expansion rate and poor electrochemical performance. The pore structure formed by using only steam and CO2 for activation is uncontrollable, the average pore size of the prepared porous carbon is large, and the proportion of micropores is low, which can result in poor cycle performance of the prepared new type of silicon-carbon negative electrode. The pore forming process by alkali activation is complex, the product has high ash content, and the wastewater is difficult to treat.

[0005] In addition, since the silicon gas phase deposition and carbon gas phase coating need to be performed at a certain gas flow rate, the particle size distribution of the porous carbon has strict requirements. If the difference between Dv90 and Dv10 of the porous carbon is too large, and the particle size distribution is too wide, there are too many fine powders compared with Dv50, which can significantly affect the effect of silicon deposition and carbon coating, resulting in poor product performance. Therefore, after the preparation of the porous carbon, necessary crushing and classification screening need to be performed before the silicon gas phase deposition, which causes a lot of cost waste. Summary of the Invention

[0006] To address the problems in the prior art, this application provides a method for preparing aerogel spherical porous carbon, a method for preparing aerogel spherical silicon-carbon anode material, and a battery. The technical solution of this application is as follows:

[0007] 1. A method for preparing aerogel spherical porous carbon, comprising:

[0008] Precursor synthesis steps: Add the polymerizable monomer, crosslinking agent, catalyst, and dispersant to water and stir. Obtain the synthesis mother liquor containing spherical aerogel precursors by sol-gel method.

[0009] Solvent replacement step: The synthesis mother liquor is centrifuged and filtered to obtain a filter cake. The filter cake is mixed with an alkaline pore-forming agent, an organic solvent is added, and the mixture is stirred to form the slurry.

[0010] Drying and dehydration step: The slurry is dried and dehydrated under a protective atmosphere to obtain a dried and dehydrated spherical aerogel precursor;

[0011] Alkali activation pore-forming step: Under a protective atmosphere and activation temperature, the dried and dehydrated spherical aerogel precursor is activated by alkali using its own rich alkaline pore-forming agent.

[0012] Gas-phase deashing step: Add acidic gas under a protective atmosphere to generate salt from the acidic gas and impurities and remove it by vaporization, to obtain a spherical aerogel precursor after gas-phase deashing;

[0013] Physical activation step: The spherical aerogel precursor after gas-phase deashing is physically activated to obtain porous carbon aerogel microspheres.

[0014] 2. The preparation method as described in item 1, wherein,

[0015] The polymer monomer is selected from any one or a combination of two or more of phenol, resorcinol, hydroquinone, catechol, melamine, cresol, and 2,4-dihydroxybenzoic acid;

[0016] The crosslinking agent is selected from any one or a combination of two or more of formaldehyde, paraformaldehyde, glutaraldehyde, hexamethylenetetramine, p-divinylbenzene, azobisisobutyronitrile, and furfural;

[0017] The catalyst is selected from any one or a combination of two or more of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, potassium hydroxide, calcium hydroxide, and sodium hydroxide; and / or,

[0018] The dispersing agent is selected from any one or more than two of gelatin, polyvinyl alcohol, polyethylene glycol, white oil, hydroxypropyl methyl cellulose, polyvinyl pyrrolidone, sodium polyacrylate, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sorbitan oleate, polyacrylamide, cyclohexane.

[0019] 3. The preparation method of item 1, wherein,

[0020] The precursor synthesis step is performed in a closed reactor under a protective atmosphere; the reaction temperature is 0-30°C, preferably 0-25°C; the reaction time is 24-96h, preferably 48-72h.

[0021] 4. The preparation method of item 1, wherein,

[0022] The alkaline pore-forming agent is selected from any one or a combination of more than two of potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate;

[0023] The organic solvent is selected from any one or a combination of more than two of isoamyl alcohol, ethanol, methanol, acetone, cyclohexane, n-dodecane, dimethyl carbonate, diethyl carbonate, ethylene carbonate; and / or,

[0024] The stirring mixing in the solvent replacement step is performed at 25-40°C, and the time used is 12-96h, preferably 48-72h.

[0025] 5. The preparation method of item 1, wherein,

[0026] The drying and dehydrating step is performed in an activated fluidized bed; the drying and dehydrating step comprises a drying sub-step and a dehydrating sub-step performed after the drying sub-step; wherein,

[0027] In the drying sub-step, the slurry is sprayed into the activated fluidized bed through a two-fluid atomizing nozzle under a protective atmosphere; the drying temperature is 40-80°C; the drying time after the slurry enters the activated fluidized bed completely is 0.5-12h;

[0028] The dehydrating temperature of the dehydrating sub-step is 200-800°C, preferably 300-600°C; the dehydrating time is 0.5-6h.

[0029] 6. The preparation method of item 1, wherein,

[0030] The alkali activation and pore-forming step is performed in an activated fluidized bed;

[0031] The activation temperature is set to 600-1000°C, preferably 750-950°C;

[0032] The activation time is 0.5-24h.

[0033] 7. The method of claim 6, wherein,

[0034] In the alkali activation step, the gas atmosphere protecting gas is continuously fed from the bottom of the gas activated fluidized bed.

[0035] 8. The method of claim 1, wherein,

[0036] The gas phase deliming step is carried out in an activated fluidized bed;

[0037] The gas phase deliming temperature is 600-1100 °C, preferably 650-950 °C;

[0038] The deliming time is 0.5-6 h.

[0039] 9. The method of claim 1, wherein,

[0040] The acidic gas is from a halogen element and / or a halogen compound; wherein,

[0041] The halogen element is selected from any one or a combination of two or more of fluorine, chlorine, bromine and iodine, preferably chlorine;

[0042] The halogen compound is selected from any one or a combination of two or more of hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, chlorine fluoride, iodine chloride, iodine bromide, bromine chloride, an acidic precursor compound, preferably hydrogen chloride; wherein the acidic precursor compound can be decomposed to produce at least one of hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, chlorine fluoride, iodine chloride, iodine bromide, bromine chloride under the heat of the alkali activation step.

[0043] 10. The method of claim 1, wherein,

[0044] The physical activation step is carried out in an activated fluidized bed, a mixed gas of a gas atmosphere protecting gas and an activating agent gas is fed from the bottom of the fluidized bed, the activating gas includes air and / or carbon dioxide; and / or,

[0045] The physical activation temperature is 300-900 °C, preferably 400-800 °C; the physical activation time is 0.5-6 h.

[0046] 11. A method for preparing a spherical silica-carbon negative electrode material aerogel, which uses the spherical porous carbon aerogel prepared by any one of the methods for preparing a spherical porous carbon aerogel of claims 1-10, comprising:

[0047] A silicon vapor deposition step: a silicon source gas is fed under a protective atmosphere to deposit silicon on the spherical porous carbon aerogel, to obtain a silicon-deposited spherical porous carbon aerogel;

[0048] The carbon gas phase coating step: under a protective atmosphere, a carbon source gas is introduced to coat the nano-silicon deposited aerogel spherical porous carbon with carbon, thereby obtaining the aerogel spherical silicon-carbon negative electrode material.

[0049] 12. The production method according to claim 11, wherein

[0050] The silicon gas phase deposition step is performed in a deposition fluidized bed.

[0051] The silicon source gas introduced under a protective atmosphere is:

[0052] A mixture gas of the protective atmosphere gas and the silicon source gas is introduced from the bottom of the deposition fluidized bed; the volume ratio of the protective atmosphere gas to the silicon source gas in the mixture gas is 10:(0.1-10).

[0053] 13. The production method according to claim 11, wherein

[0054] The carbon gas phase coating step is performed in a deposition fluidized bed.

[0055] The carbon source gas introduced under a protective atmosphere is:

[0056] A mixture gas of the protective atmosphere gas and the carbon source gas is introduced from the bottom of the deposition fluidized bed; the volume ratio of the protective atmosphere gas to the carbon source gas in the mixture gas is 10:(0.1-10).

[0057] 14. The production method according to claim 11, wherein

[0058] The silicon source gas is selected from silane and / or chlorosilane; and / or,

[0059] The carbon source gas is selected from one or a combination of two or more of alkanes, alkenes, alkynes, carbon oxides.

[0060] 15. A battery comprising:

[0061] The aerogel spherical silicon-carbon negative electrode material produced by the production method according to any one of claims 11-14.

[0062] The application provides a preparation method of aerogel spherical porous carbon. Compared with the preparation of porous carbon by taking coconut shell carbon and resin as precursors in the prior art, the aerogel spherical porous carbon prepared by the preparation method has the advantages of high pore volume, appropriate and uniform pore size, regular spherical shape (good fluidity), low ash content, appropriate and concentrated particle size distribution (without crushing and grading), and high single-particle strength. A preparation method of aerogel spherical silicon-carbon negative electrode material by using the aerogel spherical porous carbon prepared by the above method is further provided. The negative electrode material prepared by the preparation method has the advantages of lower resistivity, higher capacity, higher cycle life, stronger restriction capability (lower expansion rate) for internal silicon lithium intercalation expansion, and the like. The battery prepared by the application has higher discharge capacity, charge capacity and initial efficiency.

[0063] The above description is only a summary of the technical scheme of the application. In order to make the technical means of the application more clear and understandable, and to enable those skilled in the art to implement the content of the description, and to make the above and other purposes, features and advantages of the application more obvious and easy to understand, the specific embodiments of the application are described below. BRIEF DESCRIPTION OF DRAWINGS

[0064] Figure 1 : Electron microscope image of aerogel microspherical porous carbon in Example 1;

[0065] Figure 2 : Electron microscope image of aerogel microspherical porous carbon in Example 1;

[0066] Figure 3 : Electron microscope image of aerogel microspherical porous carbon in Example 1;

[0067] Figure 4 : Electron microscope image of aerogel microspherical porous carbon in Example 2;

[0068] Figure 5 : Electron microscope image of aerogel microspherical porous carbon in Example 2;

[0069] Figure 6 : Electron microscope image of aerogel microspherical porous carbon in Example 3;

[0070] Figure 7 : Electron microscope image of aerogel microspherical porous carbon in Example 3;

[0071] Figure 8 : Electron microscope image of porous carbon in Comparative Example 3;

[0072] Figure 9 : Electron microscope image of porous carbon in Comparative Example 3;

[0073] Figure 10 : Electron microscope image of porous carbon in Comparative Example 4;

[0074] Figure 11 : TEM image of the porous carbon in Comparative Example 4;

[0075] Figure 12 : TEM image of the aerogel precursor in Comparative Example 5. DETAILED DESCRIPTION

[0076] The best mode for carrying out the present application will be illustrated and described below. Unless otherwise defined, all terms and scientific and technical terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In case of conflict, the present application, including definitions, prevails.

[0077] The following appropriately explains the definition of the terms used particularly in the present specification and / or the basic technical content.

[0078] In the present application, "sol-gel method" refers to using a compound containing a highly chemically active component as a precursor, uniformly mixing these raw materials in a liquid phase, and performing hydrolysis and condensation chemical reactions, and in a specific solvent system, the precursor forms a three-dimensional network structure gel, and under the action of reverse phase, it is aggregated into a spherical shape to form a gel microsphere.

[0079] In the present application, "drying" refers to evaporation of water, and "dehydration" refers to removal of crystal water in the structure of alkali salt at high temperature.

[0080] In the present application, "alkaline pore-forming agent" refers to an additive that forms a pore structure by adding an alkaline substance that can be decomposed or lost on burning under high temperature or specific conditions during the preparation of the material. Specific examples can include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, etc.

[0081] In the present application, "protective atmosphere" refers to protection using nitrogen and / or a noble gas. Among them, those skilled in the art know that noble gases can include, for example, helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), etc. From an economic point of view, the present application preferably uses nitrogen as the gas for the protective atmosphere.

[0082] In the present application, "physical activation" is a material preparation process that removes part of the carbon atoms by high-temperature reaction of an activating agent gas (such as an oxidizing gas (such as air) and / or a weak oxidizing gas (such as carbon dioxide)) with a carbon-based material, increasing the porosity and specific surface area of the material.

[0083] In the present application, "activated fluidized bed" refers to a low-speed fluidized bed that makes solid particles enter a fluidized state while being in full contact with the gas by passing a high-speed gas stream through the gas distributor at the bottom of the fluidized bed

[0084] In the present application, the "deposition fluidized bed" refers to a low-speed stirring fluidized bed, in which the solid particles are brought into a fluidized state and fully contacted with the gas by passing a high-speed gas stream through a gas distributor at the bottom of the fluidized bed and the dispersion effect of the stirring paddle at the bottom.

[0085] The following embodiments are provided for better understanding of the present application, and the scope of the present application should not be limited to the following description. Therefore, it is obvious that those skilled in the art can make appropriate changes within the scope of the present application with reference to the description in the present specification. In addition, the following embodiments of the present application can be used alone or in combination.

[0086] In one aspect of the present application, a preparation method of aerogel spherical porous carbon is provided, comprising: a precursor synthesis step of stirring a polymerization monomer and a crosslinking agent, a catalyst, and a dispersing agent in water to obtain a synthesis mother liquor containing a spherical aerogel precursor by a sol-gel method; a solvent replacement step of centrifugally filtering the synthesis mother liquor to obtain a filter cake, mixing the filter cake and an alkaline pore former, adding an organic solvent, and stirring and mixing to form a slurry; a drying and dehydration step of drying and dehydrating the slurry under a protective atmosphere to obtain a dried and dehydrated spherical aerogel precursor; an alkaline activation and pore forming step of allowing the dried and dehydrated spherical aerogel precursor to be subjected to alkaline activation using the alkaline pore former rich therein under a protective atmosphere and an activation temperature; a gas-phase deashing step of adding an acidic gas under a protective atmosphere to allow the acidic gas and impurities to generate a salt and be gasified and removed to obtain a gas-phase deashed spherical aerogel precursor; and a physical activation step of physically activating the gas-phase deashed spherical aerogel precursor to obtain an aerogel microspherical porous carbon.

[0087] Compared with the prior art in which porous carbon is prepared by using coconut shell carbon, resin, etc. as a precursor and further obtaining a silicon-carbon negative electrode material, the above technical solution of the present embodiment utilizes the sol-gel method to prepare a spherical aerogel precursor rich in alkaline substances, regular in morphology (spherical), concentrated in particle size distribution, and high in single-particle strength, and utilizes the rich pore structure generated during the synthesis of the spherical aerogel precursor to further replace the solvent, activate the pores by alkaline activation, then remove a large amount of impurities including alkaline metals in the spherical aerogel precursor by a gas-phase deashing process, and then finely tune the pore structure by physical activation to prepare an aerogel microspherical porous carbon having high pore volume, appropriate and uniform pore size, regular spherical shape (good flowability), low ash content, appropriate and concentrated particle size distribution (without the need for crushing and classification), and high single-particle strength, which is used to prepare a new type of silicon-carbon negative electrode material having lower resistivity, higher capacity, longer cycle life, and stronger restriction capability (lower expansion rate) for internal silicon lithium intercalation expansion.

[0088] In one embodiment, the polymerized monomer prepared above is the main raw material in the precursor synthesis step, wherein the polymerized monomer is selected from any one or a combination of two or more of phenol, resorcinol, hydroquinone, catechol, melamine, cresol, 2,4-dihydroxybenzoic acid.

[0089] In one embodiment, the cross-linking agent is selected from any one or a combination of two or more of formaldehyde, paraformaldehyde, glutaraldehyde, hexamethylenetetramine, p-divinylbenzene, azobis isobutyronitrile, furfural, so as to ensure that the polymerized monomer is cross-linked and polymerized into a macromolecular resin through active sites.

[0090] In one embodiment, the catalyst is selected from any one or a combination of two or more of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, potassium hydroxide, calcium hydroxide, sodium hydroxide, so as to increase the cross-linking speed of the polymerized monomer and adjust the particle size and internal pore structure.

[0091] In one embodiment, the dispersant is selected from any one or a combination of two or more of gelatin, polyvinyl alcohol, polyethylene glycol, white oil, hydroxypropyl methyl cellulose, polyvinyl pyrrolidone, sodium polyacrylate, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sorbitan oleate, polyacrylamide, cyclohexane, so as to change the interfacial properties during cross-linking of the polymer, enable independent ball formation in the solvent, and prevent mutual adhesion.

[0092] In one embodiment, the precursor synthesis step is performed in a closed reactor under a protective atmosphere; the reaction temperature is 0-30°C (specifically, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C), preferably 0-25°C; and the reaction time is 24-96h (specifically, 25h, 30h, 35h, 40h, 45h, 50h, 55h, 60h, 65h, 70h, 75h, 80h, 85h, 90h, 95h), preferably 48-72h.

[0093] In one embodiment, the basic pore-forming agent is selected from any one or a combination of two or more of potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate, so as to introduce a basic pore-forming agent into the spherical aerogel precursor, facilitating subsequent alkali activation and pore formation.

[0094] In one embodiment, the organic solvent is selected from any one or a combination of two or more of isoamyl alcohol, ethanol, methanol, acetone, cyclohexane, n-dodecane, dimethyl carbonate, diethyl carbonate, ethylene carbonate.

[0095] In one embodiment, the stirring in the solvent replacement step is carried out at 25-40°C (specifically, 25°C, 30°C, 35°C, 40°C), for 12-96h (specifically, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 50h, 55h, 60h, 65h, 70h, 75h, 80h, 85h, 90h, 95h), preferably 48-72h.

[0096] In one embodiment, the drying and dehydrating step is carried out in an activated fluidized bed; the drying and dehydrating step comprises a drying sub-step and a dehydrating sub-step after the drying sub-step; in the drying sub-step, the slurry is sprayed into the activated fluidized bed through a two-fluid atomizing nozzle under a protective atmosphere; the drying temperature is 40-80°C (specifically, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C); the drying time after the slurry enters the activated fluidized bed is 0.5-12h (specifically, 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h); the dehydrating temperature in the dehydrating sub-step is 200-800°C (specifically, 200°C, 300°C, 400°C, 500°C, 600°C, 700°C, 800°C), preferably 300-600°C; the dehydrating time is 0.5-6h (specifically, 1h, 2h, 3h, 4h, 5h, 6h).

[0097] In one embodiment, the alkali activation and pore-forming step is carried out in an activated fluidized bed; the activation temperature is set to 600-1000°C (specifically, 600°C, 700°C, 800°C, 900°C, 1000°C), preferably 750-950°C; the activation time is 0.5-24h (specifically, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h).

[0098] In one embodiment, in the alkali activation and pore-forming step, a protective atmosphere gas is continuously introduced from the bottom of the gas-activated fluidized bed.

[0099] In one embodiment, the gas-phase deliming step is carried out in an activated fluidized bed; the gas-phase deliming temperature is 600-1100°C (specifically, 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C), preferably 650-950°C; the deliming time is 0.5-6h (specifically, 1h, 2h, 3h, 4h, 5h, 6h).

[0100] In one embodiment, the acid gas is from halogen element and / or halogen compound; wherein the halogen element is selected from any one or more than two combinations of fluorine, chlorine, bromine and iodine element, preferably chlorine; the halogen compound is selected from any one or more than two combinations of hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, chlorofluoride, iodine chloride, iodine bromide, bromine chloride, acid precursor compound, preferably hydrogen chloride; wherein the acid precursor compound can be decomposed to produce at least one of hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, chlorofluoride, iodine chloride, iodine bromide, bromine chloride under heat in the alkali activation pore-forming step.

[0101] In one aspect of the present application, a preparation method of aerogel spherical silicon-carbon negative electrode material is provided, which uses the aerogel spherical porous carbon prepared by any one of the above embodiments, and comprises: a silicon vapor deposition step of introducing a silicon source gas under a protective atmosphere to perform silicon deposition on the aerogel spherical porous carbon to obtain nanosilicon-deposited aerogel spherical porous carbon; and a carbon vapor coating step of introducing a carbon source gas under a protective atmosphere to perform carbon coating on the nanosilicon-deposited aerogel spherical porous carbon to obtain the aerogel spherical silicon-carbon negative electrode material.

[0102] Based on the aerogel spherical porous carbon provided by the above embodiments, the present embodiment further performs silicon vapor deposition and carbon vapor coating, so that the aerogel spherical silicon-carbon negative electrode material can be obtained. Since the aerogel spherical porous carbon obtained by the above embodiments has the characteristics of high pore volume, appropriate and uniform pore size, regular spherical shape (good fluidity), low ash content, appropriate and concentrated particle size distribution (without the need for crushing and classification), and high single-particle strength, the aerogel spherical silicon-carbon negative electrode material obtained by the present embodiment has the excellent effects of lower resistivity, high capacity, high cycle life, and stronger restriction capability (low expansion rate) for internal silicon lithium intercalation expansion, so as to be capable of being used to obtain a battery with better performance.

[0103] In one embodiment, the silicon vapor deposition step is performed in a deposition fluidized bed; the introduction of the silicon source gas under a protective atmosphere is that a mixed gas of the protective atmosphere gas and the silicon source gas is introduced from the bottom of the fluidized bed; and the volume ratio of the protective atmosphere gas to the silicon source gas in the mixed gas is 10:(0.1-10) (specifically, 10:1, 10:2, 10:3, 10:4, 10:5, 10:6, 10:7, 10:8, 10:9, 10:10).

[0104] In one embodiment, the carbon gas phase coating step is performed in a deposition fluidized bed; the carbon source gas is introduced in a protective atmosphere, which is a mixture of a protective atmosphere gas and the carbon source gas introduced from the bottom of the fluidized bed; the volume ratio of the protective atmosphere gas to the carbon source gas in the mixture is 10:(0.1-10) (specifically, 10:1, 10:2, 10:3, 10:4, 10:5, 10:6, 10:7, 10:8, 10:9, 10:10).

[0105] In one embodiment, the silicon source gas is selected from silane and / or chlorosilane.

[0106] In one embodiment, the carbon source gas is selected from one or a combination of two or more of alkanes, alkenes, alkynes, and carbon oxides.

[0107] In addition, in the silicon gas phase deposition step, the silicon gas phase deposition temperature can be 450-650°C (specifically, 450°C, 500°C, 550°C, 600°C, 650°C), preferably 500-550°C; in the carbon gas phase coating step, the carbon coating temperature can be 450-700°C (specifically, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C), preferably 500-650°C.

[0108] In one aspect of the present application, a battery is provided, which comprises the aerogel spherical silicon-carbon negative electrode material prepared by any of the above-mentioned methods for preparing aerogel spherical silicon-carbon negative electrode materials. As can be seen from the comparison of the following examples and comparative examples, the battery has higher discharge capacity, charge capacity, and initial efficiency.

[0109] Examples

[0110] The experimental methods used in the following are conventional methods unless otherwise specified.

[0111] The materials, reagents, etc. used in the following are commercially available unless otherwise specified.

[0112] Example 1

[0113] Into a jacketed reaction kettle, 19 kg of resorcinol, 1 kg of phenol, 12 kg of formaldehyde, 1 kg of sodium carbonate, 100 kg of deionized water, 50 L of sorbitan oleate, and 450 L of cyclohexane were put, 25°C cold water was introduced into the jacket of the reaction kettle for insulation, and high-purity nitrogen was used to replace the air in the reaction kettle three times to ensure that the reaction was carried out in a nitrogen atmosphere.

[0114] After stirring the reaction liquid at 25℃ for 72h, the solid material was discharged from the bottom of the reactor and centrifuged to separate the solid material. The wet solid material was mixed with 60kg of industrial potassium hydroxide and then put into 200L of acetone for solvent replacement. The mixture was stirred at 25℃ for 72h;

[0115] The slurry was transported to an activated fluidized bed heated to 40℃ by pressure. The slurry was sprayed into the fluidized bed cavity through a two-fluid atomizing nozzle under the protection of nitrogen. After the slurry was completely sprayed into the fluidized bed, the powder was dried at 40℃ for 12h. Then the activated fluidized bed was heated to 500℃ at a rate of 8℃ / min and maintained for 2h to dehydrate the powder. Nitrogen was continuously introduced into the bottom of the activated fluidized bed to purge the powder during drying and dehydration.

[0116] After dehydration was completed, the activated fluidized bed was heated to 700℃ at a rate of 2℃ / min and maintained for 12h while nitrogen was introduced into the bottom of the activated fluidized bed to alkali-activate the powder. After alkali activation was completed, the temperature was increased to 800℃ at a rate of 2℃ / min. A mixture of HCl and nitrogen was introduced into the bottom of the activated fluidized bed at a volume ratio of 1.5:8.5. The gas-phase deliming was completed after 4h;

[0117] After gas-phase deliming was completed, a mixture of nitrogen and air was introduced into the bottom of the fluidized bed at a volume ratio of 10:1. Physical activation was performed at 800℃ for 30min. Then the physical activation was completed and the temperature was allowed to decrease naturally.

[0118] The heating of the activated fluidized bed was turned off and the temperature in the activated fluidized bed was reduced to below 100℃ to obtain the aerogel spherical porous carbon. The aerogel spherical porous carbon was transported from the activated fluidized bed to the deposition fluidized bed by gas transport. The fluidized bed was heated under the protection of a nitrogen atmosphere.

[0119] When the deposition fluidized bed was heated to 520℃, the temperature was maintained constant. A mixture of monosilane and nitrogen was introduced into the bottom of the deposition fluidized bed at a volume ratio of 2:8. Silicon vapor deposition was performed for 360min. Then the monosilane was stopped and the fluidized bed was heated to 600℃ under a nitrogen atmosphere. A mixture of acetylene and nitrogen was introduced into the fluidized bed at a volume ratio of 2:8. Carbon vapor coating was performed for 360min. Then the acetylene was stopped and the heating of the fluidized bed was turned off. The fluidized bed was cooled under a nitrogen atmosphere. When the temperature of the fluidized bed was reduced to below 100℃, the reactor was discharged to obtain the aerogel spherical silicon-carbon negative electrode material.

[0120] Example 2

[0121] Into a jacketed reactor, 15 kg of resorcinol, 5 kg of melamine, 12 kg of formaldehyde, 1 kg of sodium hydroxide, 100 kg of deionized water, 50 L of sorbitan oleate, and 450 L of cyclohexane were added. The reactor jacket was cooled to 25°C to maintain the temperature, and high-purity nitrogen was used to replace the air in the reactor three times to ensure that the reaction was carried out in a nitrogen atmosphere.

[0122] After stirring the reaction solution at 25°C for 48 h, the solid material was discharged from the bottom of the reactor and centrifuged. The wet solid material was mixed with 60 kg of industrial potassium hydroxide and then added to 200 L of acetone for solvent replacement. The mixture was stirred at 25°C for 72 h.

[0123] The subsequent steps were the same as in Example 1.

[0124] Example 3

[0125] Into a jacketed reactor, 12 kg of resorcinol, 8 kg of 2,4-dihydroxybenzoic acid, 12 kg of formaldehyde, 1 kg of potassium hydroxide, 100 kg of deionized water, 50 L of sorbitan oleate, and 450 L of white oil were added. The reactor jacket was cooled to 25°C to maintain the temperature, and high-purity nitrogen was used to replace the air in the reactor three times to ensure that the reaction was carried out in a nitrogen atmosphere.

[0126] After stirring the reaction solution at 25°C for 24 h, the solid material was discharged from the bottom of the reactor and centrifuged. The wet solid material was mixed with 60 kg of industrial potassium hydroxide and then added to 200 L of acetone for solvent replacement. The mixture was stirred at 25°C for 72 h.

[0127] The subsequent steps were the same as in Example 1.

[0128] Comparative Example 1 (only basic pore-forming agent was introduced, without solvent replacement)

[0129] Into a jacketed reactor, 19 kg of resorcinol, 1 kg of phenol, 12 kg of formaldehyde, 1 kg of sodium carbonate, 100 kg of deionized water, 50 L of sorbitan oleate, and 450 L of cyclohexane were added. The reactor jacket was cooled to 25°C to maintain the temperature, and high-purity nitrogen was used to replace the air in the reactor three times to ensure that the reaction was carried out in a nitrogen atmosphere.

[0130] After the precursor synthesis, 60 kg of potassium hydroxide was added to the reactor, and the stirring was continued at 25°C for 72 h. Then, the slurry was transported to an activated fluidized bed heated to 40°C using pressure. Through a two-fluid atomizing nozzle, the slurry was sprayed into the fluidized bed cavity under nitrogen protection. After the slurry was completely sprayed into the fluidized bed, the powder was dried at 40°C for 12 h. Then, the activated fluidized bed was heated to 500°C at a rate of 8°C / min and held for 2 h to dehydrate the powder. Nitrogen was continuously introduced into the bottom of the activated fluidized bed to purge the powder during drying and dehydration.

[0131] The subsequent steps are the same as in Example 1.

[0132] Comparative Example 2 (without physical activation)

[0133] A jacketed reactor was charged with 19 kg of resorcinol, 1 kg of phenol, 12 kg of formaldehyde, 1 kg of sodium carbonate, 100 kg of deionized water, 50 L of sorbitan oleate, and 450 L of cyclohexane. The reactor jacket was cooled to 25°C, and the reactor was purged with high-purity nitrogen three times to ensure that the reaction was carried out in a nitrogen atmosphere.

[0134] After the reaction solution was stirred at 25°C for 72 h, the solid material was discharged from the bottom of the reactor and centrifuged to separate the solid material. The wet solid material was mixed with 60 kg of industrial potassium hydroxide and then placed in 200 L of acetone for solvent replacement, and stirred at 25°C for 72 h.

[0135] The slurry was transported to an activated fluidized bed heated to 40°C by pressure, and was sprayed into the fluidized bed cavity through a two-fluid atomizing nozzle under the protection of nitrogen. When the slurry was completely sprayed into the fluidized bed, the powder was dried at 40°C for 12 h, and then the activated fluidized bed was heated to 500°C at a rate of 8°C / min and maintained for 2 h to dehydrate the powder. Nitrogen was continuously introduced into the bottom of the activated fluidized bed to blow the powder during drying and dehydration.

[0136] When the dehydration was completed, the activated fluidized bed was heated to 700°C at a rate of 2°C / min and maintained for 12 h, while nitrogen was introduced into the bottom of the activated fluidized bed to activate the powder. After the alkaline activation was completed, the temperature was increased to 800°C at a rate of 2°C / min, and a mixture of HCl and nitrogen was introduced into the bottom of the activated fluidized bed at a volume ratio of 1.5:8.5, and maintained for 4 h to complete the gas-phase deliming.

[0137] After the gas-phase deliming was completed, the physical activation was not performed, and the temperature was lowered. The subsequent steps were the same as in Example 1.

[0138] Comparative Example 3 (preparation of porous carbon using phenolic resin)

[0139] A PF4012 powder resin precursor from Shengquan Group was used to cure into a block resin at 120°C, and then was crushed once. The crushed resin block was subjected to dry distillation at 500°C to obtain a resin precursor block, which was crushed a second time. 15 kg of the crushed resin precursor powder was mixed with 60 kg of industrial potassium hydroxide and then placed in 200 L of acetone for solvent replacement, and stirred at 25°C for 72 h.

[0140] The subsequent steps were the same as in Example 1.

[0141] Comparative Example 4 (preparation of non-spherical porous carbon using coconut shell carbon)

[0142] Commercial coconut shell charcoal was crushed, and 15 kg of the obtained coconut shell charcoal powder and 60 kg of industrial potassium hydroxide were mixed and then put into 200 L of acetone for solvent replacement, and stirred at 25 °C for 72 h.

[0143] The subsequent steps were the same as in Example 1.

[0144] Comparative Example 5 (without dispersant)

[0145] Into a jacketed reaction kettle were put 15 kg of resorcinol, 5 kg of melamine, 12 kg of formaldehyde, 1 kg of sodium hydroxide, and 600 kg of deionized water, and cold water at 25 °C was passed through the jacket of the reaction kettle for temperature maintenance, and high-purity nitrogen was used to replace the air in the reactor three times to ensure that the reaction was carried out in a nitrogen atmosphere.

[0146] After the reaction liquid was stirred at 25 °C for 48 h, the solid material was discharged from the bottom of the reaction kettle and centrifuged to separate out the solid material.

[0147] The subsequent steps were the same as in Example 1.

[0148] Test Examples

[0149] Porous carbon performance detection

[0150] The porous carbons of Examples 1-3 and Comparative Examples 1-4 were detected for pore volume, specific surface area, and micropore ratio by using a micromeritics ASAP 2460 multi-station extended full-automatic specific surface and porosity analyzer, and the particle size distribution of the porous carbons was tested by using a Malvern laser particle size analyzer Mastersizer 3000E, and the detection results are shown in Table 1.

[0151] Table 1: Detection results of porous carbons

[0152]

[0153]

[0154] According to the performance comparison of the porous carbon prepared according to Examples 1-3 and Comparative Examples 3-4, it can be found that the aerogel spherical porous carbon prepared according to different formulations has certain difference in particle size distribution, but the difference between Dv90 and Dv10 is between 3.12-6.72, which is much smaller than that of Comparative Examples 3-4 (27.12-32.73). This is because the growth degree of the spherical aerogel precursor can be controlled in the precursor synthesis step in Examples 1-3 to regulate the size of the microspheres, but the resin and coconut shell carbon precursor of Comparative Examples 3-4 need to be crushed to adjust the particle size. The more narrow particle size distribution of the aerogel spherical porous carbon in Examples 1-3 is beneficial to the uniformity of the silicon vapor deposition, and the prepared silicon-carbon negative electrode material has better consistency and processing performance.

[0155] Comparative Example 1 does not perform solvent replacement, and the alkaline pore-forming agent is not fully mixed with the spherical aerogel precursor, resulting in poor alkali activation effect, and the pore volume and specific surface area of the prepared aerogel microsphere porous carbon are not as good as those of Example 1. In Comparative Example 2, the proportion of micropores is too high, indicating that there are less mesopores and macropores, and the average pore size is small. The precursors of Comparative Examples 3-4 are not aerogel microspheres, and after the same activation process, the pore volume is lower than that of Example 1, and the proportion of micropores is only about 90%. Although the existence of mesopores and macropores is a penetration channel for the silicon vapor deposition into the interior of the porous carbon, a large proportion of them will lead to poor adsorption capacity of the porous carbon for silane, and increase the difficulty of carbon coating, which is not conducive to the preparation of high-capacity silicon-carbon negative electrode materials.

[0156] Porous carbon electron micrograph

[0157] The appearance of the porous carbon obtained from Examples 1-3 and Comparative Examples 3-4 and Comparative Example 5 aerogel precursor was analyzed using field emission scanning electron microscopy, and the test results are shown in Table 2. Figures 1-12 .

[0158] It can be seen that the porous carbon obtained from Comparative Example 3 has many sharp edges and corners, which is not conducive to the fluidization of the porous carbon in the subsequent step of the deposition fluidized bed, and is also not conducive to the uniform distribution of the silicon vapor deposition. Comparative Example 4 uses coconut shell carbon as the precursor, and due to the characteristics of the biomass material, it has naturally formed mesopores and macropores, which is not conducive to the adsorption of silane by the porous carbon during the silicon vapor deposition. Comparative Example 5 does not add a dispersing agent during the synthesis of the aerogel microspheres, resulting in the adhesion of the microspheres to each other, which cannot be used for the production of porous carbon. The porous carbon (aerogel spherical porous carbon) prepared in Examples 1-3 has a suitable size and is spherical, which is easy to fluidize in the deposition fluidized bed, thereby facilitating the silicon vapor deposition and carbon vapor coating.

[0159] Negative electrode material and prepared battery performance detection

[0160] For the prepared negative electrode materials of Examples 1-3 and Comparative Examples 1-4, the specific surface area of the negative electrode material was detected by using the ASAP2460 multi-station extended full-automatic specific surface and porosity analyzer of micromeritics, the carbon content of the negative electrode material was detected by using the carbon sulfur instrument (3500) of stein nak, the single particle strength of the negative electrode material was detected by using the MCT-210 micro compression tester of Japan shimadzu, and the button cell prepared by using the negative electrode material was used to detect the electrical performance of the prepared battery.

[0161] The preparation method of the button cell was as follows: the silicon-carbon negative electrode material: SP: CMC: LA136D was proportioned into a slurry according to the ratio of 75:10:2.5:12.5 (SP (Super carbon) is a conductive agent, CMC is carboxymethyl cellulose (CMC 2200), and LA136D is a water-based silicon-carbon negative electrode binder, and the materials are common materials for making button cells), the material was uniformly slurried in the ITI-300SS vacuum stirring defoaming machine of Yingtaite, then a coating machine was used for coating on a 9 μm copper foil, the coating thickness was 120 μm, the foil coated with the slurry was dried, and then cut into a circular pole piece, a lithium sheet, a circular pole piece, a ceramic PVDF separator and LB-137 were used to assemble a CR2032 battery, and the specifications of the lithium sheet were as follows: The specifications of the separator were as follows: the base film was 9 μm, the PVDF coating layer was 3 μm, and the ceramic layer was 1 μm, the electrolyte specifications were as follows: 1M LiPF6 in DMC:EC:EMC=1:1:1 Vol% with 5% FEC, 1% VC, and the amount was 60 μL.

[0162] Table 2: Negative electrode material performance and battery performance test results

[0163]

[0164]

[0165] According to the performance comparison of the silicon-carbon negative electrode materials prepared according to Examples 1-3 and Comparative Examples 1-4, it can be found that in Comparative Example 1, no solvent replacement was performed during alkali activation, the pore volume of the prepared porous carbon was poor, and the capacity of the prepared silicon-carbon material was low; in Comparative Example 2, no physical activation was performed, the internal micropore content was high, the average pore diameter was small, the amorphous silicon generated after the silane was cracked was mainly amorphous silicon, and the silicon grains were less, which would affect the reversible capacity development and the first coulombic efficiency of the silicon-carbon material, resulting in poor reversible capacity development and reduced first efficiency of the material under the same silicon deposition amount, which was not conducive to the product quality.

[0166] The appropriate micropore ratio is important for the performance of the silicon-carbon material after silicon deposition, which is conducive to the adsorption of silane gas into the channel for cracking, but if the micropore ratio is too high (such as the above comparative example 2), too many fine micropore apertures cannot pass the silane gas molecules well, thus easily causing an increase in invalid micropores, which is not conducive to the electrochemical performance of the silicon-carbon material. Meanwhile, the silicon in the fine micropores mainly deposits in the form of amorphous silicon, which has a lower reversible capacity and initial efficiency than crystalline silicon. The embodiment of the present application appropriately reduces the micropore ratio by physically activating and expanding the micropores, which can appropriately expand the fine micropore apertures. On the premise of not significantly affecting the adsorption of silane gas, the silane can better pass through the channel into the deep porous carbon, and in addition, the increased mesopores and macropores can make the silicon deposit in the form of crystalline grains, better play the electrochemical performance, and improve the reversible capacity and initial efficiency of the silicon-carbon material.

[0167] Comparative examples 3 and 4 use phenolic resin and coconut shell carbon as precursors, respectively, to prepare porous carbon with a low pore volume, and the electrochemical performance of the silicon-carbon negative electrode material prepared therefrom is poor.

[0168] Comparative example 3 uses blocky phenolic resin as a porous carbon precursor, and the prepared porous carbon is non-spherical after crushing. The particle strength of the silicon-carbon material prepared by depositing silicon on the carrier is poorer than that of the aerogel microsphere porous carbon. Comparative example 4 uses biomass coconut shell carbon as a porous carbon precursor, and the particle strength is lower than that of the resin precursor. When the low particle strength silicon-carbon negative electrode material is used as the negative electrode material of the battery, the silicon will swell during lithium intercalation and deintercalation. If the binding ability of the porous carbon to the silicon swelling is low, it will lead to poor cycle performance of the battery, which cannot meet the requirements of long-term use.

Claims

1. A method for preparing aerogel spherical porous carbon, comprising: a precursor synthesis step: adding a polymerization monomer and a crosslinking agent, a catalyst, and a dispersing agent into water and stirring to obtain a synthesis mother liquor containing a spherical aerogel precursor by a sol-gel method; a solvent replacement step: centrifugally filtering the synthesis mother liquor to obtain a filter cake, mixing the filter cake and an alkaline pore-forming agent, adding an organic solvent, and stirring to form a slurry; a drying and dehydration step: drying and dehydrating the slurry in a protective atmosphere to obtain a dried and dehydrated spherical aerogel precursor; an alkaline activation and pore-forming step: allowing the dried and dehydrated spherical aerogel precursor to be subjected to alkaline activation by using the alkaline pore-forming agent contained therein under a protective atmosphere and at an activation temperature; a gas-phase deashing step: adding an acidic gas under a protective atmosphere, allowing the acidic gas and impurities to form a salt and be gasified and removed, and obtaining a gas-phase deashed spherical aerogel precursor; a physical activation step: physically activating the gas-phase deashed spherical aerogel precursor to obtain an aerogel microsphere porous carbon; wherein the polymerization monomer is selected from any one or a combination of two or more of phenol, resorcinol, hydroquinone, catechol, melamine, cresol, and 2,4-dihydroxybenzoic acid; the crosslinking agent is selected from any one or a combination of two or more of formaldehyde, paraformaldehyde, glutaraldehyde, hexamethylenetetramine, p-divinylbenzene, and azobis isobutyronitrile; the catalyst is selected from any one or a combination of two or more of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, potassium hydroxide, calcium hydroxide, and sodium hydroxide; the dispersing agent includes any one or a combination of two or more of sodium dodecylbenzenesulfonate, sodium dodecylsulfate, and sorbitan oleate, and any one or both of white oil and cyclohexane. 2.The method according to claim 1, wherein the precursor synthesis step is performed in a closed reactor under a protective atmosphere; the reaction temperature is 0-30 ℃; and the reaction time is 24-96 h. 3.The method according to claim 2, wherein the reaction temperature is 0-25 ℃. 4.The method according to claim 2, wherein the reaction time is 48-72 h. 5.The method according to claim 1, wherein the alkaline pore-forming agent is selected from any one or a combination of two or more of potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate; the organic solvent is selected from any one or a combination of two or more of isoamyl alcohol, ethanol, methanol, acetone, cyclohexane, n-dodecane, dimethyl carbonate, diethyl carbonate, and ethylene carbonate; and / or the stirring in the solvent replacement step is performed at 25-40 ℃ for 12-96 h. 6.The method according to claim 5, wherein the stirring is performed for 48-72 h. 7.The method according to claim 1, wherein the drying and dehydration step is performed in an activated fluidized bed; and the drying and dehydration step includes a drying sub-step and a dehydration sub-step performed after the drying sub-step; wherein In the drying sub-step, the slurry is sprayed into an activated fluidized bed through a two-fluid atomizing nozzle under a protective atmosphere; the drying temperature is 40-80℃; and the drying time after the slurry has entered the activated fluidized bed is 0.5-12h. The dehydrating temperature in the dehydrating sub-step is 200-800℃; and the dehydrating time is 0.5-6h.

8. The preparation method of claim 7, wherein, the dehydrating temperature is 300-600℃.

9. The preparation method of claim 1, wherein, the alkali activation pore-forming step is performed in an activated fluidized bed; the activation temperature is set to 600-1000℃; the activation time is 0.5-24h.

10. The preparation method of claim 9, wherein, the activation temperature is set to 750-950℃.

11. The preparation method of claim 9, wherein, in the alkali activation pore-forming step, a gas used as a protective atmosphere is continuously introduced from the bottom of the activated fluidized bed.

12. The preparation method of claim 1, wherein, the gas-phase deashing step is performed in an activated fluidized bed; the gas-phase deashing temperature is 600-1100℃; the deashing time is 0.5-6h.

13. The preparation method of claim 12, wherein, the gas-phase deashing temperature is 650-950℃.

14. The preparation method of claim 1, wherein, the acid gas is derived from a halogen element and / or a halogen compound; wherein, the halogen element is selected from any one or a combination of two or more of fluorine, chlorine, bromine, and iodine; the halogen compound is selected from any one or a combination of two or more of hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, fluorine chloride, chlorine iodide, bromine iodide, chlorine bromide, and an acid precursor compound; wherein the acid precursor compound can decompose to produce at least one of hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, fluorine chloride, chlorine iodide, bromine iodide, and chlorine bromide when heated in the alkali activation pore-forming step.

15. The preparation method of claim 14, wherein, the halogen element is chlorine gas; the halogen compound is hydrogen chloride.

16. The preparation method of claim 1, wherein, the physical activation step is performed in an activated fluidized bed, a mixed gas of a gas used as a protective atmosphere and an activator gas is introduced from the bottom of the fluidized bed, and the activator gas includes air and / or carbon dioxide; and / or, the temperature for physical activation is 300-900℃; and the physical activation time is 0.5-6h.

17. The preparation method of claim 16, wherein, the temperature for physical activation is 400-800℃.

18. A preparation method of aerogel spherical silicon-carbon negative electrode material, which uses the aerogel spherical porous carbon prepared by any one of the preparation methods of aerogel spherical porous carbon in claims 1-17, comprising: a silicon vapor deposition step: introducing a silicon source gas under a protective atmosphere to perform silicon deposition on the aerogel spherical porous carbon, to obtain nanosilicon-deposited aerogel spherical porous carbon. Carbon gas phase coating step: under a protective atmosphere, a carbon source gas is introduced to deposit a carbon coating on the nano-silicon deposited aerogel spherical porous carbon, to obtain the aerogel spherical silicon-carbon negative electrode material.

19. The production method according to claim 18, wherein, the silicon gas deposition step is performed in a deposition fluidized bed; the silicon source gas is introduced under a protective atmosphere by: introducing a mixed gas of the gas used as the protective atmosphere and the silicon source gas from the bottom of the deposition fluidized bed; the volume ratio of the gas used as the protective atmosphere to the silicon source gas in the mixed gas is 10: (0.1 to 10).

20. The production method according to claim 18, wherein, the carbon gas phase coating step is performed in a deposition fluidized bed; the carbon source gas is introduced under a protective atmosphere by: introducing a mixed gas of the gas used as the protective atmosphere and the carbon source gas from the bottom of the deposition fluidized bed; the volume ratio of the gas used as the protective atmosphere to the carbon source gas in the mixed gas is 10: (0.1 to 10).

21. The production method according to claim 18, wherein, the silicon source gas is selected from silane and / or chlorosilane; and / or, the carbon source gas is selected from one or a combination of two or more of an alkane, an alkene, an alkyne, and a carbon oxide.

22. A battery comprising: the aerogel spherical silicon-carbon negative electrode material produced by the production method of the aerogel spherical silicon-carbon negative electrode material according to any one of claims 18 to 21.

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