Method for preparing a cellular spherical porous carbon and applications thereof

Abstract

The application provides a preparation method of a honeycomb spherical porous carbon, which comprises the following steps: resin synthesis reaction, spray drying, pre-carbonization, water vapor activation and carbon dioxide activation in sequence to obtain the honeycomb spherical porous carbon; wherein in the resin synthesis reaction, polymer monomers, a pore forming agent, a crosslinking agent, an initiator, a dispersing agent, a modifier and a solvent are mixed to react to form a honeycomb spherical resin.

Description

Technical Field

[0001] This application belongs to the field of battery materials application, specifically involving a method for preparing honeycomb spherical porous carbon and its application. Background Technology

[0002] Silicon-carbon anode materials are considered ideal for next-generation lithium-ion batteries due to their high specific capacity (up to 4200 mAh / g), but their high volume expansion rate (>300%) and poor cycle stability hinder their practical application. Chemical vapor deposition (CVD), which deposits nano-silicon in a porous carbon matrix and coats it with a carbon layer, has become a key technological approach to solving these problems. CVD silicon-carbon anode materials use porous carbon as a substrate, performing vapor deposition in an atmosphere containing a silicon source to deposit nano-silicon into the porous carbon channels. Then, in an atmosphere containing a carbon source, a carbon layer is coated onto the material surface. The resulting silicon-carbon composite material, used as a battery anode material, achieves high capacity and long cycle life while effectively improving the high expansion and low rate capability drawbacks of silicon-based anode materials.

[0003] Currently, porous carbon used in vapor-phase silicon carbide deposition is classified into biomass-based and resin-based types according to the type of raw materials. Biomass-based porous carbon mainly refers to porous carbon obtained by activating and pore-forming coconut shell carbon, characterized by low cost and simple process. Resin-based porous carbon is represented by porous carbon obtained by activating and pore-forming phenolic resin carbonization, which has stable quality and better performance than coconut shell carbon.

[0004] Silicon-carbon materials prepared from porous coconut shell carbon exhibit better rate performance compared to resin-based silicon-carbon materials, due to the natural macropores and mesopores in the porous carbon substrate, which facilitate lithium-ion transport on the material surface. However, the numerous natural macropores and mesopores result in lower particle strength of the coconut shell porous carbon, making it more prone to breakage and pulverization during charge-discharge cycles, leading to poorer cycle performance. Summary of the Invention

[0005] The applicant discovered that the precursor resin of resin-based porous carbon, through curing and cross-linking, can achieve a stable and uniform material structure with high particle strength, maintaining structural stability during charge and discharge processes and achieving a long cycle life. However, due to the lack of channels above mesopores, lithium-ion transfer on the material surface is not conducive, resulting in relatively poor rate performance.

[0006] To address the problems in the prior art, this application provides a honeycomb spherical carbon, a method for preparing silicon-carbon anode materials using this honeycomb spherical carbon, and its application. The silicon-carbon anode material prepared by this method exhibits significantly improved rate performance and cycle life, making it an ideal lithium-ion battery anode material. The technical solution of this application is as follows: 1. A method for preparing honeycomb spherical porous carbon, comprising the following steps: It is successively subjected to resin synthesis reaction, spray drying, pre-carbonization, steam activation and carbon dioxide activation to obtain honeycomb spherical porous carbon; In the synthesis reaction, polymeric monomers, pore-forming agents, crosslinking agents, initiators, dispersants, modifiers, and solvents are mixed and reacted to form honeycomb spherical resins.

[0007] 2. According to the method described in item 1, wherein, The polymer monomer is selected from resorcinol; The pore-forming agent is selected from polyvinyl alcohol; The crosslinking agent is selected from formaldehyde; The initiator is selected from ammonium persulfate; The dispersant is selected from polyacrylamide. The modifier is selected from ammonium fluoride; The solvent is selected from water.

[0008] 3. According to the method described in item 1, wherein, Relative to 1 part by weight of polymer monomer, the crosslinking agent is 0.05-1.25 parts by weight; the pore-forming agent is 0.01-1 parts by weight; the initiator is 0.005-0.5 parts by weight; the dispersant is 0.01-0.5 parts by weight; the modifier is 0.001-0.1 parts by weight; and the solvent is 0.1-10 parts by weight.

[0009] 4. According to the method described in item 1, wherein, The temperature for resin synthesis reaction is 100-200℃.

[0010] 5. According to the method described in item 1, wherein, The spray drying temperature is 100-150℃.

[0011] 6. According to the method described in item 1, wherein, Pre-carbonization, steam activation, and carbon dioxide activation are carried out in a region where a protective gas is formed, and the region where the protective gas is formed is respectively provided with a third temperature region, a second temperature region, and a first temperature region from top to bottom. Preferably, the protective gas is selected from one or both of nitrogen and argon.

[0012] 7. According to the method described in item 6, wherein, In the pre-carbonization step, the temperature is gradually increased from 400℃ to 900℃; Preferably, in the pre-carbonization step, The temperature in the first temperature zone is 400℃-450℃, the temperature in the second temperature zone is 450℃-600℃, and the temperature in the third temperature zone is 600℃-900℃.

[0013] 8. According to the method described in item 6, wherein, In the steam activation step, a mixture of steam and protective gas is introduced for activation; Preferably, in the steam activation step, the temperature of the first temperature zone is 700℃-800℃, the temperature of the second temperature zone is 800℃-850℃, and the temperature of the third temperature zone is 850℃-950℃. More preferably, The ratio of water vapor volumetric flow rate to protective gas volumetric flow rate is 1:0.1-20.

[0014] 9. According to the method described in item 6, wherein, In the carbon dioxide activation step, a mixture of carbon dioxide and protective gas is introduced for activation. Preferably, in the carbon dioxide activation step, the temperature of the first temperature zone is 850℃-900℃, the temperature of the second temperature zone is 900℃-950℃, and the temperature of the third temperature zone is 950℃-1000℃.

[0015] More preferably, The ratio of carbon dioxide volumetric flow rate to protective gas volumetric flow rate is 1:0.1-10.

[0016] 10. The preparation method according to item 6, wherein, The heights of the third, second, and first temperature zones are determined based on the reaction inner diameter D0, as follows: The height of the third temperature zone is 1.0D0-2.5D0; The height of the second temperature zone is 1.0D0-2.5D0; The height of the first temperature zone is 1.0D0-2.5D0.

[0017] 11. A honeycomb spherical resin, prepared by the method described in any one of items 1-10.

[0018] 12. An apparatus for implementing the preparation method described in any one of items 1-10, wherein a third temperature region, a second temperature region, and a first temperature region are respectively arranged from top to bottom.

[0019] 13. The device according to item 12, wherein, The heights of the third, second, and first temperature zones are determined based on the reaction inner diameter D0, as follows: The height of the third temperature zone is 1.0D0-2.5D0; The height of the second temperature zone is 1.0D0-2.5D0; The height of the first temperature zone is 1.0D0-2.5D0.

[0020] 14. The device according to item 12, wherein, The equipment is selected from fluidized bed reactors.

[0021] 15. A method for preparing silicon-carbon anode materials using the honeycomb spherical porous carbon prepared by any one of the preparation methods described in items 1-10, the honeycomb spherical porous carbon described in item 11, or the honeycomb spherical porous carbon prepared by any one of the apparatuses described in items 12-14, comprising: Silicon source gas is introduced under a protective atmosphere, and silicon vapor deposition is performed on the porous carbon. Subsequently, a carbon source gas is introduced under a protective atmosphere to perform carbon coating, thereby obtaining silicon-carbon anode material.

[0022] 16. The method according to item 15, wherein, The silicon source gas is selected from silanes and / or chlorosilanes; The carbon source gas is selected from one or more of alkanes, alkenes, and alkynes.

[0023] 17. A battery, characterized in that it comprises a silicon-carbon anode material prepared by the method described in item 15 or 16.

[0024] Technical effects: Improving the rate performance of silicon-carbon anode materials: This application introduces a pore-forming agent and a special resin synthesis process to form a micron-scale honeycomb pore structure on the porous carbon surface, thereby increasing the electrolyte contact area and improving ion transport efficiency.

[0025] Improving the cycle stability of silicon-carbon anode materials: The resin-based porous carbon prepared in this application has high single-particle strength and stable structure, which can effectively buffer the volume expansion of silicon during lithium intercalation. Cyclic tests show that the capacity decay of this material is significantly slowed down during long cycles, which is better than coconut shell carbon-based and some traditional resin-based materials.

[0026] Achieving a balance between rate performance and cycle life: This application optimizes the formulation and process to introduce an open pore structure similar to coconut shell charcoal while maintaining the high strength of the resin-based material.

[0027] The process offers high controllability and is suitable for large-scale production: This application employs a continuous process of resin synthesis + spray drying + multi-stage activation, with clearly defined conditions and adjustable parameters. The equipment can utilize a fluidized bed reactor to achieve zoned temperature control, making it suitable for continuous industrial production.

[0028] The material structure is adjustable to meet different application requirements: This application allows for the control of the pore size distribution, specific surface area, and surface properties of porous carbon by adjusting the proportions of polymer monomers, pore-forming agents, and modifiers. For example, the addition of ammonium fluoride can introduce defects in the carbon layer, further improving lithium-ion transport efficiency.

[0029] Suitable for high-performance lithium-ion batteries: The silicon-carbon anode material prepared using this porous carbon exhibits high specific capacity, high initial efficiency, and good cycle stability in both coin cells and pouch cells. It is suitable for next-generation lithium-ion battery systems with high energy density and long cycle life. Attached Figure Description

[0030] Figure 1 SEM images of the precursor in Example 1 are shown; Figure 2 SEM images of the precursor in Comparative Example 1 are shown; Figure 3 SEM images of the precursor in Comparative Example 2 are shown; Figure 4 SEM images of the precursor in Comparative Example 3 are shown; Figure 5 SEM images of the precursors in Comparative Example 4 are shown; Figure 6 SEM images of the precursors in Comparative Example 5 are shown; Figure 7 SEM images of the precursors in Comparative Example 6 are shown; Figure 8 SEM images of the precursors in Comparative Example 7 are shown; Figure 9 SEM images of the precursors in Comparative Example 8 are shown; Figure 10 SEM images of the precursors in Comparative Example 9 are shown; Figure 11 A comparison chart of sample cycle performance is shown; Figure 12 A schematic diagram of a honeycomb spherical carbon production device is shown. Detailed Implementation

[0031] The best mode of the invention will be shown 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 invention pertains. In the event of any inconsistency, this application (including the definitions) takes precedence.

[0032] The following appropriately explains the definitions of terms and / or basic technical content used in particular in this specification.

[0033] In this application, "polymer monomer" refers to an aromatic derivative containing hydroxyl groups that can polymerize into a network or / and chain polymer under certain conditions. Examples of polymer monomers include phenol, resorcinol, hydroquinone, methylphenol, etc.

[0034] In this application, "porous carbon" refers to porous carbon materials prepared by physical or chemical activation using biomass or resin as a substrate. These materials have the characteristics of high pore volume, high specific surface area, and high micropore ratio, making them suitable as substrate materials for preparing novel silicon-carbon anode materials by vapor deposition.

[0035] In this application, "protective gas" refers to nitrogen and / or rare gases. Those skilled in the art will know that rare gases include, for example, helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe). From an economic perspective, nitrogen is preferred as the protective gas in this application.

[0036] In this application, "fluidized bed" refers to a low-speed stirred fluidized bed in which a high-speed gas flow is introduced through a gas distributor at the bottom of the fluidized bed, and the dispersion effect of the stirring paddle at the bottom causes solid particles to enter a fluidized state and make full contact with the gas.

[0037] In this application, "carbon source gas" refers to one or more of alkanes, alkenes, alkynes, and carbon oxides, which can perform carbon vapor deposition on materials at high temperatures.

[0038] In this application, "silicon source gas" refers to gaseous silicon-containing compounds such as silanes (e.g., silane, disilane) and / or chlorosilanes (e.g., silanes), which can be decomposed at high temperatures to generate nano-silicon, allowing for vapor-phase silicon deposition within a carbon framework. This application preferably uses silane as the silicon source gas.

[0039] This application provides a method for preparing honeycomb spherical porous carbon, which includes the following steps: the carbon is sequentially subjected to a resin synthesis reaction, spray drying, pre-carbonization, steam activation and carbon dioxide activation to obtain honeycomb spherical porous carbon; wherein, in the resin synthesis reaction, polymeric monomers, pore-forming agents, crosslinking agents, initiators, dispersants, modifiers and solvents are mixed and reacted to form honeycomb spherical resin.

[0040] In some embodiments of this application, the polymeric monomer is selected from resorcinol.

[0041] In some embodiments of this application, the pore-forming agent is selected from polyvinyl alcohol.

[0042] In some embodiments of this application, the crosslinking agent is selected from formaldehyde.

[0043] In some embodiments of this application, the initiator is selected from ammonium persulfate.

[0044] In some embodiments of this application, the dispersant is selected from polyacrylamide.

[0045] In some embodiments of this application, the modifier is selected from ammonium fluoride.

[0046] In some embodiments of this application, the solvent is selected from water.

[0047] In some embodiments of this application, the crosslinking agent is 0.05-1.25 parts by weight relative to 1 part by weight of polymer monomer; for example, the crosslinking agent can be 0.05 parts by weight, 0.10 parts by weight, 0.15 parts by weight, 0.20 parts by weight, 0.25 parts by weight or any range therebetween.

[0048] In some embodiments of this application, the pore-forming agent is 0.01-1 parts by weight relative to 1 part by weight of the polymer monomer; for example, the pore-forming agent can be 0.01 parts by weight, 0.05 parts by weight, 0.10 parts by weight, 0.15 parts by weight, 0.20 parts by weight, 0.25 parts by weight, 0.30 parts by weight, 0.35 parts by weight, 0.40 parts by weight, 0.45 parts by weight, 0.50 parts by weight, 0.55 parts by weight, 0.60 parts by weight, 0.65 parts by weight, 0.70 parts by weight, 0.75 parts by weight, 0.80 parts by weight, 0.85 parts by weight, 0.90 parts by weight, 0.95 parts by weight, 1 part by weight, or any range between these values.

[0049] In some embodiments of this application, the initiator is 0.005-0.5 parts by mass relative to 1 part by mass of polymer monomer; for example, the initiator can be 0.005 parts by mass, 0.01 parts by mass, 0.05 parts by mass, 0.1 parts by mass, 0.15 parts by mass, 0.2 parts by mass, 0.25 parts by mass, 0.3 parts by mass, 0.35 parts by mass, 0.4 parts by mass, 0.45 parts by mass, 0.5 parts by mass, or any range thereof.

[0050] In some embodiments of this application, the dispersant is 0.01-0.5 parts by mass relative to 1 part by mass of polymer monomer; the dispersant can be 0.01 parts by mass, 0.05 parts by mass, 0.1 parts by mass, 0.15 parts by mass, 0.2 parts by mass, 0.25 parts by mass, 0.3 parts by mass, 0.35 parts by mass, 0.4 parts by mass, 0.45 parts by mass, 0.5 parts by mass, or any range thereof.

[0051] In some embodiments of this application, the modifier is 0.001-0.1 parts by mass relative to 1 part by mass of polymer monomer; the modifier can be 0.001 parts by mass, 0.005 parts by mass, 0.01 parts by mass, 0.02 parts by mass, 0.03 parts by mass, 0.04 parts by mass, 0.05 parts by mass, 0.06 parts by mass, 0.07 parts by mass, 0.08 parts by mass, 0.09 parts by mass, 0.1 parts by mass, or any range thereof.

[0052] In some embodiments of this application, the solvent is 0.1-10 parts by weight relative to 1 part by weight of the polymer monomer. The solvent can be 0.1 parts by weight, 0.5 parts by weight, 1.0 parts by weight, 1.5 parts by weight, 2.0 parts by weight, 2.5 parts by weight, 3.0 parts by weight, 3.5 parts by weight, 4.0 parts by weight, 4.5 parts by weight, 5.0 parts by weight, 5.5 parts by weight, 6.0 parts by weight, 6.5 parts by weight, 7.0 parts by weight, 7.5 parts by weight, 8.0 parts by weight, 8.5 parts by weight, 9.0 parts by weight, 9.5 parts by weight, 10 parts by weight, or any range between them.

[0053] In some embodiments of this application, the temperature of the resin synthesis reaction is 100-200°C; for example, the temperature of the resin synthesis reaction can be 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C or any range thereof.

[0054] In some embodiments of this application, the spray drying temperature is 100-150°C; for example, the spray drying temperature can be 100°C, 110°C, 120°C, 130°C, 140°C, 150°C or any range thereof.

[0055] In some embodiments of this application, pre-carbonization, steam activation, and carbon dioxide activation are carried out in a region where a protective gas is formed, and the region where the protective gas is formed is respectively provided with a third temperature region, a second temperature region, and a first temperature region from top to bottom.

[0056] In some embodiments of this application, the protective gas is selected from one or both of nitrogen and argon.

[0057] In some embodiments of this application, the temperature is gradually increased from 400°C to 900°C during the pre-carbonization step.

[0058] In some embodiments of this application, the temperature of the first temperature region is 400℃-450℃, for example, the temperature of the first temperature region can be 400℃, 410℃, 420℃, 430℃, 440℃, 450℃ or any range therebetween; the temperature of the second temperature region is 450℃-600℃, for example, the temperature of the second temperature region can be 450℃, 460℃, 470℃, 480℃, 490℃, 500℃, 510℃, 520℃, 530℃, 540℃, 550℃, 560℃, 570℃, 580℃, 590℃, 600℃ or any range therebetween. The temperature of the third temperature region is 600℃-900℃. For example, the temperature of the third temperature region can be 600℃, 610℃, 620℃, 630℃, 640℃, 650℃, 660℃, 670℃, 680℃, 690℃, 700℃, 710℃, 720℃, 730℃, 740℃, 750℃, 760℃, 770℃, 780℃, 790℃, 800℃, 810℃, 820℃, 830℃, 840℃, 850℃, 860℃, 870℃, 880℃, 890℃, 900℃ or any range between them.

[0059] In some embodiments of this application, the steam activation step involves introducing a mixture of steam and protective gas for activation.

[0060] In some embodiments of this application, in the steam activation step, the temperature of the first temperature region is 700℃-800℃, for example, the temperature of the first temperature region can be 700℃, 710℃, 720℃, 730℃, 740℃, 750℃, 760℃, 770℃, 780℃, 790℃, 800℃ or any range therebetween; the temperature of the second temperature region is 800℃-850℃, for example, the temperature of the second temperature region can be 800℃, 810℃, 820℃, 830℃, 840℃, 850℃ or any range therebetween; the temperature of the third temperature region is 850℃-950℃, for example, the temperature of the third temperature region can be 850℃, 860℃, 870℃, 880℃, 890℃, 900℃, 910℃, 920℃, 930℃, 940℃, 950℃ or any range therebetween.

[0061] In some embodiments of this application, the ratio of water vapor volume flow rate to protective gas volume flow rate is 1:0.1-20. For example, the ratio of water vapor volume flow rate to protective gas volume flow rate can be 1:0.1, 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20 or any range therebetween.

[0062] In some embodiments of this application, the carbon dioxide activation step involves introducing a mixture of carbon dioxide and a protective gas for activation.

[0063] In some embodiments of this application, during the carbon dioxide activation step, the temperature of the first temperature region is 850℃-900℃, for example, the temperature of the first temperature region can be 850℃-900℃, 850℃, 860℃, 870℃, 880℃, 890℃, 900℃ or any range thereof; the temperature of the second temperature region is 900℃-950℃, for example, the temperature of the second temperature region can be 900℃, 910℃, 920℃, 930℃, 940℃, 950℃ or any range thereof; the temperature of the third temperature region is 950℃-1000℃, for example, the temperature of the third temperature region can be 950℃, 960℃, 970℃, 980℃, 990℃, 1000℃ or any range thereof.

[0064] In some embodiments of this application, the volumetric flow rate of carbon dioxide and the volumetric flow rate of protective gas are 1:0.1-10. For example, the volumetric flow rate of carbon dioxide and the volumetric flow rate of protective gas can be 1:0.1, 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 or any range thereof.

[0065] In some embodiments of this application, the heights of the third temperature region, the second temperature region, and the first temperature region are determined according to the reaction inner diameter D0.

[0066] In some embodiments of this application, the height of the third temperature region is 1.0D0-2.5D0; the height of the second temperature region is 1.0D0-2.5D0; and the height of the first temperature region is 1.0D0-2.5D0. For example, the height of the third temperature region can be 1.0D0, 1.1D0, 1.2D0, 1.3D0, 1.4D0, 1.5D0, 1.6D0, 1.7D0, 1.8D0, 1.9D0, 2.0D0, 2.1D0, 2.2D0, 2.3D0, 2.4D0, 2.5D0, or any range thereof; the height of the second temperature region can be 1.0D0, 1.1D0, 1.2D0, 1.3D0, 1.4D0, 1.5D0, 1.6D0, 1.7D0, or any range thereof. The values ​​of D0, 1.8D0, 1.9D0, 2.0D0, 2.1D0, 2.2D0, 2.3D0, 2.4D0, 2.5D0 or any range thereof; the height of the first temperature region can be 1.0D0, 1.1D0, 1.2D0, 1.3D0, 1.4D0, 1.5D0, 1.6D0, 1.7D0, 1.8D0, 1.9D0, 2.0D0, 2.1D0, 2.2D0, 2.3D0, 2.4D0, 2.5D0 or any range thereof.

[0067] In some embodiments of this application, the device is selected from a fluidized bed, where the reaction inner diameter D0 is the inner diameter of the fluidized bed.

[0068] This application provides a honeycomb spherical resin prepared by the above method.

[0069] This application provides an apparatus for implementing the above-described preparation method, which has a third temperature region, a second temperature region, and a first temperature region arranged from top to bottom.

[0070] In some embodiments of this application, the heights of the third temperature region, the second temperature region, and the first temperature region are determined according to the reaction inner diameter D0, specifically as follows: the height of the third temperature region is 1.0D0-2.5D0; the height of the second temperature region is 1.0D0-2.5D0; and the height of the first temperature region is 1.0D0-2.5D0. For example, the height of the third temperature region can be 1.0D0, 1.1D0, 1.2D0, 1.3D0, 1.4D0, 1.5D0, 1.6D0, 1.7D0, 1.8D0, 1.9D0, 2.0D0, 2.1D0, 2.2D0, 2.3D0, 2.4D0, 2.5D0, or any range thereof; the height of the second temperature region can be 1.0D0, 1.1D0, 1.2D0, 1.3D0, 1.4D0, 1.5D0, 1.6D0, 1.7D0, or any range thereof. The values ​​of D0, 1.8D0, 1.9D0, 2.0D0, 2.1D0, 2.2D0, 2.3D0, 2.4D0, 2.5D0 or any range thereof; the height of the first temperature region can be 1.0D0, 1.1D0, 1.2D0, 1.3D0, 1.4D0, 1.5D0, 1.6D0, 1.7D0, 1.8D0, 1.9D0, 2.0D0, 2.1D0, 2.2D0, 2.3D0, 2.4D0, 2.5D0 or any range thereof.

[0071] In some embodiments of this application, the device is selected from fluidized beds.

[0072] This application provides a method for preparing silicon-carbon anode materials using the honeycomb spherical porous carbon prepared by the above-described preparation method, the honeycomb spherical porous carbon prepared by the above-described equipment, and the honeycomb spherical porous carbon prepared by the above-described preparation method. The method includes: introducing a silicon source gas under a protective atmosphere and performing silicon vapor deposition on the porous carbon; subsequently introducing a carbon source gas under a protective atmosphere to perform carbon coating to obtain silicon-carbon anode materials.

[0073] In some embodiments of this application, the silicon source gas is selected from silanes and / or chlorosilanes.

[0074] In some embodiments of this application, the carbon source gas is selected from one or more of alkanes, alkenes, and alkynes.

[0075] This application provides a battery comprising a silicon-carbon anode material prepared by the above method.

[0076] The embodiments provided below are provided to better understand the present invention, and the scope of this application should not be limited to the following description. Therefore, it is apparent to those skilled in the art that appropriate modifications can be made within the scope of the present invention with reference to the description herein. Furthermore, the following embodiments of the present invention can be used alone or in combination.

[0077] Example 1 40 kg of resorcinol monomer, 1 kg of polyvinyl alcohol (PVA2299) pore-forming agent, 20 kg of formaldehyde (40%) crosslinking agent, 0.6 kg of ammonium persulfate (98.5%) initiator, 3 kg of polyacrylamide (P1108) dispersant, and 242 kg of water solvent were added to a homogeneous reactor. The reactor was stirred and the synthesis reaction was carried out at 140°C for 24 hours.

[0078] After 24 hours of reaction, feed is introduced into the reactor with a mixed solution containing 0.24 kg of ammonium fluoride and 10 kg of water. The reaction is continued for another 6 hours before being terminated.

[0079] After the synthesis reaction is complete, stop stirring the reactor and allow the solution to settle and separate into layers.

[0080] After settling for 24 hours, solid-liquid stratification was observed through the manhole. Then, the bottom discharge valve was opened to allow the solid slurry to enter the spray drying tower at a certain flow rate for spray drying. The temperature of the spray drying tower was set at 130℃.

[0081] After drying, the material is collected and fed into an activated fluidized bed for pre-carbonization treatment. Based on the inner diameter D0 of the fluidized bed reaction zone, the heights of the first temperature zone (1.0D0), the second temperature zone (1.0~2.0D0), and the third temperature zone (2.0~5.5D0) are set. Temperature zone 1 is set at 450℃, temperature zone 2 at 550℃, and temperature zone 3 at 700℃. Protective nitrogen gas enters the fluidized bed from the bottom at a flow rate of 6 L / min. A screw propeller at the bottom of the fluidized bed continuously transports the material from the first temperature zone to the second temperature zone, and then circulates it along the inner wall to the bottom. In the high-temperature environment of the first and second temperature zones, the volatile substances contained in the material turn into gases and enter the higher-temperature third temperature zone with the nitrogen gas, preventing solidification into tar and ensuring it is discharged from the fluidized bed with the exhaust gas.

[0082] After the dry distillation is completed, the material is activated by steam. The material in the fluidized bed is kept mixed with the screw propeller. The first temperature zone is set to 750℃, the second temperature zone to 850℃, and the third temperature zone to 950℃. The volume flow rate of the protective gas nitrogen is reduced to 2 L / min. Steam is introduced at a rate of 0.045 kg / min and introduced for 8 hours before stopping, thus completing the steam activation.

[0083] After steam activation is complete, CO2 activation begins. Temperature zones 1 are set to 850℃, 2 to 950℃, and 3 to 1000℃. Nitrogen flow rate is maintained at 2 L / min, and CO2 is introduced at a flow rate of 0.2 L / min for 60 min. Then, CO2 is introduced at a flow rate of 0.8 L / min for 30 min before the process ends.

[0084] After activation, 2.4 kg of honeycomb spherical porous carbon was obtained, which was used for vapor deposition of silicon to prepare a novel silicon-carbon anode material.

[0085] 1.2 kg of porous carbon was added to a fluidized bed, and a mixture of nitrogen and silane was introduced at 520 °C for 800 min to perform silicon vapor deposition. Then, a mixture of nitrogen and acetylene was introduced for 240 min to perform carbon coating at high temperature.

[0086] After carbon coating, the fluidized bed is cooled to room temperature before discharge, and the material is characterized and analyzed.

[0087] Comparative Example 1 (without pore-forming agent polyvinyl alcohol (PVA2299)) Based on Example 1, a porous carbon sample was obtained without adding the pore-forming agent polyvinyl alcohol.

[0088] Comparative Example 2 (without initiator ammonium persulfate (98.5%)) Based on Example 1, a porous carbon sample was obtained without adding the initiator ammonium persulfate.

[0089] Comparative Example 3 (without dispersant polyacrylamide (P1108)) Based on Example 1, a porous carbon sample was obtained without the addition of polyacrylamide.

[0090] Comparative Example 4 (without formaldehyde crosslinking agent) Based on Example 1, a porous carbon sample was obtained without the addition of the crosslinking agent formaldehyde. Comparative Example 5 (Excessive formaldehyde added as a crosslinking agent) Based on Example 1, the amount of formaldehyde added was increased from 40% to 50 kg, resulting in a porous carbon sample.

[0091] Comparative Example 6 (without the modifier ammonium fluoride) Add 40 kg resorcinol, 1 kg polyvinyl alcohol (PVA2299), 30 kg formaldehyde (40%), 0.6 kg ammonium persulfate (98.5%), 3 kg polyacrylamide (P1108), and 236 kg water to a homogenized reactor. Start the reactor and stir. The synthesis reaction is carried out at 140°C for 30 hours.

[0092] After the resin synthesis reaction is complete, stop stirring the reactor and allow the solution to settle and separate into layers.

[0093] After settling for 24 hours, solid-liquid stratification was observed through the manhole. Then, the bottom discharge valve was opened to allow the solid slurry to enter the spray drying tower at a certain flow rate for spray drying. The temperature of the spray drying tower was set at 130℃.

[0094] After drying, the material is collected and fed into an activated fluidized bed for pre-carbonization treatment. Based on the inner diameter D0 of the fluidized bed reaction zone, the heights of the first temperature zone (1.0D0), the second temperature zone (1.0~2.0D0), and the third temperature zone (2.0~5.5D0) are set. Temperature zone 1 is set at 450℃, temperature zone 2 at 550℃, and temperature zone 3 at 700℃. Protective nitrogen gas enters the fluidized bed from the bottom at a flow rate of 6 L / min. A screw propeller at the bottom of the fluidized bed continuously transports the material from the first temperature zone to the second temperature zone, and then circulates it along the inner wall to the bottom. In the high-temperature environment of the first and second temperature zones, the volatile substances contained in the material turn into gases and enter the higher-temperature third temperature zone with the nitrogen gas, preventing solidification into tar and ensuring it is discharged from the fluidized bed with the exhaust gas.

[0095] After the dry distillation is completed, the material is activated by steam. The material in the fluidized bed is kept mixed with the screw propeller. The first temperature zone is set to 750℃, the second temperature zone to 850℃, and the third temperature zone to 950℃. The volume flow rate of the protective gas nitrogen is reduced to 2 L / min. Steam is introduced at a rate of 0.045 kg / min and introduced for 8 hours before stopping, thus completing the steam activation.

[0096] After steam activation is complete, CO2 activation begins. Temperature zones 1 are set to 850℃, 2 to 950℃, and 3 to 1000℃. Nitrogen flow rate is maintained at 2 L / min, and CO2 is introduced at a flow rate of 0.2 L / min for 60 min. Then, CO2 is introduced at a flow rate of 0.8 L / min for 30 min before the process ends.

[0097] After activation, 2.4 kg of honeycomb spherical porous carbon was obtained, which was used for vapor deposition of silicon to prepare a novel silicon-carbon anode material.

[0098] 1.2 kg of porous carbon was added to a fluidized bed, and a mixture of nitrogen and silane was introduced at 520 °C for 800 min to perform silicon vapor deposition. Then, a mixture of nitrogen and acetylene was introduced for 240 min to perform carbon coating at high temperature.

[0099] After carbon coating, the fluidized bed is cooled to room temperature before discharge, and the material is characterized and analyzed.

[0100] Comparative Example 7 (Coconut Shell-Based Comparative Sample) A novel silicon-carbon anode sample was prepared using coconut shell-based porous carbon produced by Shandong Shengquan New Energy Technology Co., Ltd. as raw material.

[0101] 1.2 kg of porous carbon was added to a fluidized bed, and a mixture of nitrogen and silane was introduced at 520 °C for 800 min to perform silicon vapor deposition. Then, a mixture of nitrogen and acetylene was introduced for 240 min to perform carbon coating at high temperature.

[0102] After carbon coating, the fluidized bed is cooled to room temperature before discharge, and the material is characterized and analyzed.

[0103] Comparative Example 8 (Spherical Resin Comparison Sample) A novel silicon-carbon anode sample was prepared using ZLQ-2 porous carbon produced by Shandong Shengquan New Energy Technology Co., Ltd. as raw material.

[0104] 1.2 kg of porous carbon was added to a fluidized bed, and a mixture of nitrogen and silane was introduced at 520 °C for 800 min to perform silicon vapor deposition. Then, a mixture of nitrogen and acetylene was introduced for 240 min to perform carbon coating at high temperature.

[0105] After carbon coating, the fluidized bed is cooled to room temperature before discharge, and the material is characterized and analyzed.

[0106] Comparative Example 9 (Pure Resin Spherical Comparison Sample) A novel silicon-carbon anode sample was prepared using ZMC-2 porous carbon produced by Shandong Shengquan New Energy Technology Co., Ltd. as raw material.

[0107] 1.2 kg of porous carbon was added to a fluidized bed, and a mixture of nitrogen and silane was introduced at 520 °C for 800 min to perform silicon vapor deposition. Then, a mixture of nitrogen and acetylene was introduced for 240 min to perform carbon coating at high temperature.

[0108] After carbon coating, the fluidized bed is cooled to room temperature before discharge, and the material is characterized and analyzed.

[0109] Product characteristics: For the materials obtained in Example 1 and Comparative Examples 1-4, the specific surface area of ​​the negative electrode material was measured using a Micromeritics ASAP2460 multi-station extended fully automated specific surface area and porosity analyzer. The carbon content of the negative electrode material was measured using a NAK Carbon-Sulfur Analyzer (3500). XRD analysis was performed using a Rigaku SmartlabSE X-ray diffractometer. The powder resistivity of the material was measured using a Dandong Baite powder compaction density analyzer. The electrical performance of the prepared cells was tested using button cells made from the negative electrode material.

[0110] The preparation method of the soft-pack battery is as follows: The ternary cathode material, Ruixiang RL05-S3, was used. The cathode active material was configured with a ratio of PVDF:CNT:SP = 97.20:1.3:0.5:1. The silicon-carbon sample and graphite were configured with a ratio of 1:9 as the anode active material. The anode active material was configured with a ratio of CNT:SBR:CMC:PAA:SP = 95.71:0.09:1.7:1.2:0.3:1. After homogenization, coating, rolling, cutting, stacking, sealing, drying, liquid injection, pre-charging, and formation, the materials were subjected to cycle testing.

[0111] The preparation method of button batteries is as follows: Silicon-carbon anode material: SP:CMC:LA136D is mixed in a ratio of 75:10:2.5:12.5 to form a slurry (SP (Super carbon) is a conductive agent, CMC is carboxymethyl cellulose (CMC 2200), and LA136D is an aqueous silicon-carbon anode binder; all materials are commonly used in button battery manufacturing). The material is homogenized in an ITI-300SS vacuum mixer and degasser, and then coated onto 9μm copper foil using a coating machine to a thickness of 120μm. After drying the coated foil, it is cut into... The CR2032 battery uses circular electrodes, lithium plates, a ceramic PVDF separator, and LB-137 to assemble the cells. Lithium plate specifications: Membrane specifications: base membrane 9μm, PVDF coating 3μm, ceramic layer 1μm; electrolyte specifications: 1M LiPF6 in DMC:EC:EMC=1:1:1 Vol% with 5% FEC, 1% VC; dosage: 60μL.

[0112] Rate performance testing method: The prepared button cell battery was subjected to cyclic charge and discharge experiments at 0.1C, 0.2C, 0.5C and 1C to test its capacity decay.

[0113] The test results are detailed in Tables 1 and 2.

[0114] Table 1: Test Results of Sample Material Properties and Battery Performance

[0115] Table 2: Results of Rate Performance Tests for Sample Materials

[0116] Analysis of the scanning electron microscope (SEM) images of the porous carbon prepared in Example 1 and Comparative Examples 1-9 reveals significant differences in microstructure among the materials obtained under different synthesis conditions. The material prepared in Example 1 exhibits a regular spherical morphology with densely packed micron-sized pores on its surface. The spherical particles are well-dispersed and have a relatively uniform particle size distribution. Comparative Example 1, without the addition of the pore-forming agent polyvinyl alcohol, yielded a relatively smooth surface with no micron-sized pore structure. Comparative Example 2, without the addition of the initiator ammonium persulfate, failed to coagulate and form micron-sized spheres during in-situ polymerization, resulting in a loose resin aggregate composed of nano-sized resin particles. Comparative Example 3, without the addition of a dispersant, yielded a dense resin mass. Comparative Example 4, without the addition of the crosslinking agent formaldehyde, resulted in insufficient crosslinking of the cured resin, leading to weak micron-sized sphere structures formed by nano-sized resin particles that broke during drying. Comparative Example 5, due to the addition of excessive formaldehyde, resulted in a crosslinking and curing time exceeding the process window, forming micron-sized spheres with a dense surface. The morphological characteristics of Comparative Examples 1 to 5 do not meet the product requirements.

[0117] The materials from Examples 1 and Comparative Examples 6-9 were prepared into silicon-carbon composite materials by vapor deposition, and their electrochemical performance was characterized. Table 1 shows that the silicon-carbon composite materials obtained by vapor deposition of the above materials have similar reversible specific capacity and initial coulombic efficiency at the 0.8 V platform, and similar physicochemical properties. Among them, the silicon-carbon material obtained by Comparative Example 7 (prepared using coconut shell carbon) has the lowest single-particle strength, only 169 MPa. Examples 1, Comparative Examples 6, 8, and 9 all used resin-based porous carbon to prepare silicon-carbon materials, with Comparative Example 9 (prepared using smooth spherical porous carbon) having the highest single-particle strength (775 MPa). Compared to Comparative Example 9, Comparative Example 8 has slightly poorer particle dispersion and exhibits some adhesion, resulting in a corresponding decrease in its single-particle strength. Examples 1 and Comparative Example 6 are both micron-spherical structures formed by the polymerization of nanoparticles; although their single-particle strength is lower than that of the smooth spherical Comparative Example 9, it is significantly higher than that of Comparative Example 7. Single-particle strength is correlated with the cycling performance of a material. Higher single-particle strength can, to some extent, reflect the material's resistance to fracture during lithium-ion intercalation expansion, helping to maintain the structural integrity of the material during charge-discharge cycles and avoiding capacity decay due to pulverization. This is combined with the material's cycling performance curves ( Figure 11As can be seen, Comparative Example 7, with the lowest single-particle strength, exhibited significant capacity decay during cycling; Comparative Example 9, with the highest single-particle strength, showed a significantly improved capacity decay rate compared to Comparative Examples 7 and 8. The single-particle strength of Examples 1 and 6 was significantly higher than that of Comparative Example 7, and comparable to that of Comparative Example 8. However, thanks to their unique internal structure (i.e., microspheres composed of aggregated nanoparticles with abundant macroporous spaces), the expansion stress during lithium intercalation was effectively absorbed by the internal channels of the spheres, thus significantly reducing the volume expansion of the microspheres themselves and consequently significantly improving cycling performance.

[0118] Compared to coconut shell carbon-based materials, resin-based porous carbon has a denser carbon layer structure and fewer defects, resulting in relatively poor rate performance of silicon-carbon composite materials. Table 2 shows that Comparative Example 7 exhibits the highest reversible specific capacity (683.87 mAh / g) at a current density of 1C.

[0119] Both Example 1 and Comparative Example 6 exhibit a macroporous channel structure on their surfaces. This structure increases the contact interface between the electrolyte and the material when used as an anode material, thereby promoting ion transport efficiency. Therefore, the rate performance of the two samples is significantly better than that of Comparative Examples 8 and 9. Comparative Example 6 did not add ammonium fluoride during preparation, but ammonium fluoride can increase the layered structural defects of carbon materials and improve the lithium-ion transport efficiency on the material surface. Therefore, compared with Example 1, the reversible specific capacity of Comparative Example 6 at 1C is significantly reduced (only 640.16 mAh / g). Example 1 effectively improved the high-current fast charging performance by introducing ammonium fluoride, with a 1C reversible specific capacity as high as 675.33 mAh / g and a capacity retention rate of 32.45%, which is similar to that of coconut shell carbon-based silicon-carbon material (Comparative Example 7, 32.97%). In summary, the silicon-carbon composite material prepared using the process of this application has both excellent fast charging performance and cycle stability, making it a silicon-carbon anode material with excellent comprehensive performance.

Claims

1. A method for preparing honeycomb spherical porous carbon, comprising the following steps: It is successively subjected to resin synthesis reaction, spray drying, pre-carbonization, steam activation and carbon dioxide activation to obtain honeycomb spherical porous carbon; In the resin synthesis reaction, polymeric monomers, pore-forming agents, crosslinking agents, initiators, dispersants, modifiers, and solvents are mixed and reacted to form honeycomb-shaped spherical resins.

2. The method according to claim 1, wherein, The polymer monomer is selected from resorcinol; The pore-forming agent is selected from polyvinyl alcohol; The crosslinking agent is selected from formaldehyde; The initiator is selected from ammonium persulfate; The dispersant is selected from polyacrylamide. The modifier is selected from ammonium fluoride; The solvent is selected from water.

3. The method according to claim 1, wherein, The crosslinking agent is 0.05-1.25 parts by weight relative to 1 part by weight of the polymer monomer; the pore-forming agent is 0.01-1 parts by weight. The initiator is 0.005-0.5 parts by weight; the dispersant is 0.01-0.5 parts by weight; the modifier is 0.001-0.1 parts by weight; and the solvent is 0.1-10 parts by weight.

4. The method according to claim 1, wherein, The temperature for resin synthesis reaction is 100-200℃.

5. The method according to claim 1, wherein, The spray drying temperature is 100-150℃.

6. The method according to claim 1, wherein, Pre-carbonization, steam activation, and carbon dioxide activation are carried out in a region where a protective gas is formed, and the region where the protective gas is formed is respectively provided with a third temperature region, a second temperature region, and a first temperature region from top to bottom. Preferably, the protective gas is selected from one or both of nitrogen and argon.

7. The method according to claim 6, wherein, In the pre-carbonization step, the temperature is gradually increased from 400℃ to 900℃; Preferably, in the pre-carbonization step, The temperature in the first temperature zone is 400℃-450℃, the temperature in the second temperature zone is 450℃-600℃, and the temperature in the third temperature zone is 600℃-900℃.

8. The method according to claim 6, wherein, In the steam activation step, a mixture of steam and protective gas is introduced for activation; Preferably, in the steam activation step, the temperature of the first temperature zone is 700℃-800℃, the temperature of the second temperature zone is 800℃-850℃, and the temperature of the third temperature zone is 850℃-950℃. More preferably, The ratio of water vapor volumetric flow rate to protective gas volumetric flow rate is 1:0.1-20.

9. The method according to claim 6, wherein, In the carbon dioxide activation step, a mixture of carbon dioxide and protective gas is introduced for activation. Preferably, in the carbon dioxide activation step, the temperature of the first temperature region is 850℃-900℃, the temperature of the second temperature region is 900℃-950℃, and the temperature of the third temperature region is 950℃-1000℃; More preferably, The ratio of carbon dioxide volumetric flow rate to protective gas volumetric flow rate is 1:0.1-10.

10. The preparation method according to claim 6, wherein, The heights of the third, second, and first temperature zones are determined based on the reaction inner diameter D0, as follows: The height of the third temperature zone is 1.0D0-2.5D0; The height of the second temperature zone is 1.0D0-2.5D0; The height of the first temperature zone is 1.0D0-2.5D0.

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