High-capacity sodium ion battery carbon negative electrode material as well as preparation method and application thereof

Abstract

The invention relates to a high-capacity sodium-ion battery carbon negative electrode material and a preparation method and application thereof.The high-capacity sodium-ion battery carbon negative electrode material is prepared through the following steps that S1, petroleum coke is smashed to the target particle size, then mixed with hydrochloric acid and stirred at the constant temperature for t1, then a certain mass of a sodium tripolyphosphate aqueous solution x is added, constant-temperature stirring is continued for t2, filtering and washing are conducted, and precursor powder is obtained; and S2, mixing the precursor powder with a sodium tripolyphosphate aqueous solution y containing glucose, carrying out spray drying, mixing with high-softening-point asphalt, carrying out fusion granulation, carrying out gradient heating treatment in an inert atmosphere, and carrying out depolymerization and demagnetization on the obtained material to obtain the carbon negative electrode material. Compared with the prior art, the sodium ion battery carbon negative electrode material with high capacity and long cycle life is obtained.

Description

Technical Field

[0001] This invention relates to the field of sodium-ion battery technology, specifically to a high-capacity sodium-ion battery carbon anode material, its preparation method, and its application. Background Technology

[0002] The large-scale commercial application of sodium-ion batteries is hampered by the lack of low-cost, high-performance carbon anode materials. Petroleum coke is an excellent raw material for preparing carbon materials, with advantages such as low cost and simple carbonization process. Applying it to sodium-ion battery anode materials can greatly leverage the low-cost advantage of sodium-ion batteries. However, its high content of metallic impurities such as iron, nickel, and vanadium leads to problems such as poor cycle life and low cell energy density in sodium-ion batteries. Current technologies for removing metallic impurities include acid treatment and alkali treatment processes. While these can effectively remove metallic impurities, they both cause drastic changes to the structure of the petroleum coke material, resulting in carbon materials with extremely large specific surface areas. This leads to extremely low first-cycle coulombic efficiency, poor cycle performance, and low energy density in sodium-ion batteries. Furthermore, the poor wettability of petroleum coke with water means that acid or alkali treatment processes consume large amounts of water, causing wastewater treatment problems.

[0003] Chinese patent CN117923459A uses hydrochloric acid and other methods to treat petroleum coke, followed by high-temperature treatment to obtain a porous carbon anode material with a large specific surface area. However, due to the excessively large specific surface area and 002 diffraction peak spacing of the final carbon material (less than 0.36 nm), this material exhibits extremely low first-cycle coulombic efficiency, poor cycle performance, and a specific capacity below 280 mAh / g when used as an anode material for sodium-ion batteries, failing to meet commercialization requirements.

[0004] Chinese patent CN 114956037 describes the treatment of petroleum coke with potassium hydroxide and borax, followed by high-temperature treatment to obtain carbon materials. The interlayer spacing of the 002 diffraction peaks is only 0.35 nm, and the specific capacity of the material is less than 280 mAh / g.

[0005] Chinese patent CN 117776147 addresses the problem of excessively large specific surface area of ​​petroleum coke after alkali treatment by using asphalt as a filling operation to obtain carbon materials with a 002 diffraction peak interlayer spacing exceeding 0.38 nm, but with a specific capacity lower than 250 mAh / g.

[0006] Chinese patent CN116119643B discloses a method for preparing pyrolytic carbon anode materials for high-rate, long-cycle sodium storage. The method involves: 1) pulverizing carbon-based precursor materials such as coke or char to obtain a primary carbon-based precursor with a specified particle size; 2) pre-treating the primary precursor with acid-alkali washing or alkali activation to obtain a pre-treated secondary precursor; 3) granulating / pyrolyzing the primary precursor to obtain the finished carbon-based anode material; and 4) further modifying the surface of the carbon-based anode material to achieve an optimized pyrolytic carbon anode material. The prepared carbon-based anode material exhibits advantages such as large reversible capacity, high initial charge-discharge coulombic efficiency, and good cycle performance in sodium-ion batteries. However, the maximum reversible specific capacity of the carbon material prepared by this method is only 255 mAh / g, which cannot meet the requirements of commercial sodium-ion batteries for anode materials. Furthermore, the alkali activation and pore-forming operation reduces the tap density of the carbon material, further affecting the energy density of the sodium-ion battery. Therefore, this method still needs improvement. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art and provide a high-capacity sodium-ion battery carbon anode material with high thermal stability, its preparation method and application. While solving the problem of metal impurities in petroleum coke, it maintains the stability of the carbon skeleton structure of petroleum coke, and prepares a sodium-ion battery carbon anode material that takes into account both high capacity and long cycle life.

[0008] The objective of this invention can be achieved through the following technical solution: a method for preparing a high-capacity sodium-ion battery carbon anode material, comprising the following steps:

[0009] S1. Crush the petroleum coke to the target particle size, then mix it with hydrochloric acid, stir at a constant temperature for t1, then add a certain mass of sodium tripolyphosphate aqueous solution x, continue stirring at a constant temperature for t2, filter and wash to obtain precursor powder.

[0010] S2. The precursor powder is mixed with an aqueous solution of sodium tripolyphosphate containing glucose, spray-dried, and then mixed with high softening point asphalt for fusion granulation. Finally, it is subjected to gradient heating treatment under an inert atmosphere. The resulting material is depolymerized and demagnetized to obtain carbon anode material.

[0011] Furthermore, the petroleum coke mentioned in step S1 is black solid coke produced by a coking unit from vacuum residue of petroleum; the target particle size of the petroleum coke is D50 = 2-5 μm.

[0012] Further, the ratio of petroleum coke to hydrochloric acid used in step S1 is (400-600) g : (0.5-2) L;

[0013] The hydrochloric acid has a pH of 1 and a concentration of 0.05–0.15 mol / L, preferably 0.1 mol / L.

[0014] Sodium tripolyphosphate is classified into α-type and β-type according to its crystal structure. In step S1, the sodium tripolyphosphate aqueous solution x is a mixture of α-type sodium tripolyphosphate and water at a mass ratio of 6 to 13:100; the mass ratio of α-type sodium tripolyphosphate to petroleum coke is 5 to 10:100.

[0015] Furthermore, the conditions for constant temperature stirring t1 in step S1 are: in a sealed reaction vessel, under an oxygen atmosphere, at 20-40℃, with a stirring rate of 50-200 r / min and a stirring time of 1-3 h;

[0016] The conditions for constant temperature stirring t2 are: in a closed reaction vessel, under an oxygen atmosphere, at 40-100℃, with a stirring rate of 50-200 r / min and a stirring time of 1-4 h; preferably 40-70℃, with a stirring rate of 50-100 r / min and a stirring time of 2-4 h.

[0017] Further, step S1, filtration and washing, involves washing the filter multiple times with deionized water until the pH of the filtrate is ≤10.

[0018] Furthermore, the sodium tripolyphosphate aqueous solution y containing glucose in step S2 is a mixture of glucose, sodium β-tripolyphosphate, and deionized water in a mass ratio of 1-5:3-13:100.

[0019] Further, in step S2, the precursor powder and the sodium tripolyphosphate aqueous solution y containing glucose are uniformly mixed at a mass ratio of 100:150-250 to form mixture A.

[0020] Further, in step S2, the spray drying process yields mixture A, which is spray dried at an inlet temperature of 200-250℃ and an outlet temperature of <105℃ to obtain powder particles. These particles are then uniformly mixed with high softening point asphalt at a mass ratio of 100:10-20 to obtain mixture B. Mixture B is then loaded into a graphite sagger and subjected to gradient heating treatment at a heating rate of 2℃ / min-10℃ / min, heating to 650℃ (T1), holding at that temperature for 2-6 hours, and then heating at 2-5℃ / min to 900-1200℃ (T2), holding at that temperature for 4-12 hours.

[0021] This invention also provides an application of a high-capacity sodium-ion battery carbon anode material, in which the carbon anode material is used as the anode material for a sodium-ion secondary battery.

[0022] In a preferred application, the negative electrode material is combined with a conductive agent and a binder to prepare a negative electrode slurry. Both the conductive agent and the binder are materials known in the industry. The negative electrode slurry is then loaded onto the surface of a conductive current collector to obtain a negative electrode sheet. Conventional methods, such as coating methods, can be used to coat the negative electrode material of this invention onto the conductive current collector to form the negative electrode sheet. The coating method and the conductive current collector are methods and materials known in the industry.

[0023] In a further preferred application, the negative electrode plate, positive electrode plate, separator, and electrolyte are assembled into a sodium-ion secondary battery.

[0024] The present invention also provides a sodium-ion secondary battery anode comprising the carbon anode material obtained by the preparation method described above.

[0025] The present invention also provides a sodium-ion secondary battery comprising a carbon anode material based on high-sulfur petroleum coke prepared by the aforementioned preparation method.

[0026] The sodium-ion secondary battery wherein the negative electrode sheet comprises the carbon negative electrode material.

[0027] Preferably, the sodium-ion secondary battery is a sodium-ion battery.

[0028] Sodium tripolyphosphate (STP), as a surfactant, significantly improves the wettability of petroleum coke with water through emulsification, allowing it to penetrate the interior of petroleum coke particles. Under alkaline conditions, STP can complex with metal ions such as iron, nickel, zinc, vanadium, and calcium, thereby removing impurity metal elements from the petroleum coke. Compared to conventional treatments using sodium hydroxide, nitric acid, and hydrochloric acid, STP has minimal impact on the molecular structure of petroleum coke. Simultaneously, at certain temperatures, STP can act as a crosslinking agent and phosphorus source, forming carbon-phosphorus, sulfur-phosphorus, and oxygen-phosphorus chemical bonds with the carbon chains in petroleum coke. The crosslinked petroleum coke forms a three-dimensional macromolecular structure, inhibiting the graphitization process at high temperatures, thus yielding carbon materials with larger 002 diffraction peak interlayer spacing. The adsorption of alkali metal ions by carbon-phosphorus and oxygen-phosphorus bonds, and the reversible redox process of carbon-phosphorus and sulfur-phosphorus bonds during cycling, improve the specific capacity and long-cycle performance of petroleum coke-based carbon materials treated with STP.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1. This invention innovatively utilizes sodium tripolyphosphate under mild reaction conditions to remove metallic impurities from petroleum coke. Simultaneously, the cross-linking reaction between phosphorus atoms and petroleum coke inhibits the graphitization process of petroleum coke during high-temperature processing, thereby expanding the interlayer spacing of the petroleum coke-based carbon material d002. Glucose effectively reduces the volume of pores within the petroleum coke to accommodate more sodium ions and also reduces side reactions between the material and the electrolyte. The carbon material prepared using petroleum coke as a raw material, when used as a negative electrode in a sodium-ion battery, achieves a reversible specific capacity of 318.6 mAh / g and a first-week coulombic efficiency of 87.7%; while the first-week coulombic efficiency of sodium-ion battery carbon negative electrode materials obtained by conventional processing methods is <80%.

[0031] 2. This invention solves the problem of metallic impurities in petroleum coke while preventing the formation of numerous pores and defects inside the petroleum coke, thus maintaining the stability of the carbon skeleton structure of the petroleum coke and preparing a sodium-ion battery carbon anode material that combines high capacity and long cycle life.

[0032] 3. The preparation method of the material of the present invention has the characteristics of short process, simple operation, low cost and environmental friendliness. Attached Figure Description

[0033] Figure 1 The images show the Raman spectra of the carbon materials in Example 1 and Comparative Example 6. Detailed Implementation

[0034] The following examples illustrate the specific steps of the present invention. It should be understood that these examples are merely illustrative and not intended to limit the scope of the invention in any way. Various processes and methods not described in detail in this invention are conventional methods known in the art.

[0035] All raw materials involved in this invention are commercially available products in the field. In the following embodiments, the petroleum coke has an ash content of <1%, sodium α-tripolyphosphate has a purity of >99%, and sodium β-tripolyphosphate has a purity of >99%.

[0036] Example 1

[0037] A high-capacity sodium-ion battery carbon anode material is prepared by the following method:

[0038] S1. Crush petroleum coke into primary particles with a particle size D50 = 3 μm, then take 1000 g and mix it with 2 L of hydrochloric acid (pH = 1, 0.1 mol / L) in a sealed reactor. Under an oxygen atmosphere, stir at 25℃ (t1) and a stirring rate of 60 r / min for 2 h. Then add 1000 g of 10% sodium α-tripolyphosphate aqueous solution and mix. Heat to 60℃ (t2) and stir at 60 r / min for 2 h. Filter and wash the filter cake several times with deionized water until the pH of the filtrate is ≤10 to obtain the precursor powder.

[0039] S2. Weigh 1000g of the dried precursor powder, 20g of glucose, 60g of sodium β-tripolyphosphate, and 2000g of deionized water, mix them evenly, and spray dry them at an inlet temperature of 210℃ and an outlet temperature of 100℃. The collected particles are mixed with asphalt with a softening point >210℃ at a mass ratio of 100:10, granulated, and placed in a graphite mortar. The temperature is increased to 650℃ (T1) at 5℃ / min and held for 2 hours, then increased to 1050℃ (T2) at 5℃ / min and held for 6 hours to obtain black agglomerated powder. After depolymerization and demagnetization, carbon anode material is obtained. Depolymerization and demagnetization are conventional operations in the field, and the equipment used is also common equipment in the field. For example, in this embodiment, depolymerization is performed by airflow crushing and grading equipment (common equipment in the industry), and the particle size D90 of the material is <30 micrometers, and D50 is 6-8 micrometers.

[0040] S3. The obtained carbon anode material is mixed with conductive agent Super P, dispersant NaCMC, binder SBR, and ultrapure water (18 MΩ / cm, 25℃) at a mass ratio of 8:1:0.4:0.6:15. The mixture is thoroughly mixed using a dual planetary mixer to obtain anode slurry. The obtained anode material is then coated onto conductive current collector aluminum foil and dried to form anode electrode sheet with an areal density of 6-10 mg / cm³. 2 ;

[0041] S4. In accordance with T / DCB 010—2024 "Technical Requirements for Hard Carbon Anode Materials for Sodium-ion Batteries", CR2032 coin cells were assembled in a dry glove box filled with argon gas, using the carbon anode electrode as the working electrode, metallic sodium as the counter electrode, 1 mol / L NaPF6 EC / DEC (volume ratio 1:1) as the electrolyte, and glass fiber as the separator. Electrochemical performance tests were conducted at room temperature in the voltage range of 0.001-2.0V, and the charge / discharge test current density was 0.1C.

[0042] Example 2

[0043] Compared with Example 1, the only difference is that D50 = 5μm, and the other operations and parameters are the same as in Example 1.

[0044] Example 3

[0045] Compared with Example 1, the only difference is that T2 is changed to 950°C, and the other operations and parameters are the same as in Example 1.

[0046] Example 4

[0047] Compared with Example 1, the only difference is that the isothermal time of T2 is changed to 4 hours, while other operations and parameters are the same as in Example 1.

[0048] Example 5

[0049] Compared with Example 1, the only difference is that the stirring time of 2 hours at 60°C (t2) and 60 r / min is changed to stirring time of 1 hour at 70°C and 100 r / min. All other operations and parameters are the same as in Example 1.

[0050] Example 6

[0051] Compared with Example 1, the only difference is that instead of raising the temperature at 5℃ / min to 650℃ (T1), holding it at that temperature for 2 hours, and then raising it at 5℃ / min to 1050℃ (T2) and holding it at that temperature for 6 hours, the temperature is raised at 2℃ / min to 650℃ (T1), held at that temperature for 1 hour, and then raised it at 2℃ / min to 1050℃ (T2) and held it at that temperature for 3 hours. All other operations and parameters are the same as in Example 1.

[0052] Comparative Example 1

[0053] Compared with Example 1, the only difference is that sodium β-tripolyphosphate is not added; all other operations and parameters are the same as in Example 1.

[0054] Comparative Example 2

[0055] Compared with Example 1, the only difference is that sodium α-tripolyphosphate is not added; all other operations and parameters are the same as in Example 1.

[0056] Comparative Example 3

[0057] Compared with Example 1, the only difference is that glucose is not added; all other operations and parameters are the same as in Example 1.

[0058] Comparative Example 4

[0059] Compared with Example 1, the only difference is that sodium α- and β-type tripolyphosphate are not added; all other operations and parameters are the same as in Example 1.

[0060] Comparative Example 5

[0061] 1000g of primary petroleum coke particles with a particle size of 3μm were crushed, mixed with 20g of glucose and 2000g of deionized water, and spray-dried at an inlet temperature of 210℃ and an outlet temperature of 100℃. The collected particles were mixed with asphalt with a softening point >210℃ at a mass ratio of 100:10, granulated, and placed in a graphite crucible. The temperature was increased to 650℃ (T1) at 5℃ / min and held for 2 hours, then increased to 1050℃ (T2) at 5℃ / min and held for 6 hours to obtain a black agglomerated powder. After deagglomeration and demagnetization, this powder became the carbon anode material. The obtained carbon anode material was mixed with conductive agent Super P, dispersant NaCMC, binder SBR, and ultrapure water (18 MΩ / cm, 25℃) at a mass ratio of 8:1:0.4:0.6:15. The mixture was thoroughly stirred using a dual planetary mixer to obtain an anode slurry. This anode material was then coated onto a conductive current collector aluminum foil and dried to form the anode electrode sheet. The areal density of the electrode sheet was 6-10 mg / cm³. 2 ;

[0062] According to T / DCB 010—2024 "Technical Requirements for Hard Carbon Anode Materials for Sodium-ion Batteries", CR2032 coin cells were assembled in a dry glove box filled with argon gas, using the aforementioned carbon anode electrode as the working electrode, metallic sodium as the counter electrode, 1 mol / L NaPF6 EC / DEC (volume ratio 1:1) as the electrolyte, and glass fiber as the separator. Electrochemical performance tests were conducted at room temperature in the voltage range of 0.001-2.0V, and the charge / discharge test current density was 0.1C.

[0063] Comparative Example 6

[0064] Petroleum coke particles with a crushed diameter of 3 μm were placed in a graphite crucible and heated to 650℃ (T1) at a rate of 5℃ / min, held at that temperature for 2 hours, and then heated to 1050℃ (T2) at a rate of 5℃ / min, held at that temperature for 6 hours, to obtain a black agglomerated powder. This powder, after deagglomeration and demagnetization, became the carbon anode material. The obtained carbon anode material was mixed with conductive agent Super P, dispersant NaCMC, binder SBR, and ultrapure water (18 MΩ / cm, 25℃) at a mass ratio of 8:1:0.4:0.6:15. The mixture was thoroughly mixed using a dual planetary mixer to obtain a negative electrode slurry. The obtained negative electrode material was then coated onto a conductive current collector aluminum foil, dried, and used to form a negative electrode sheet with an areal density of 6-10 mg / cm³. 2 ;

[0065] According to T / DCB 010—2024 "Technical Requirements for Hard Carbon Anode Materials for Sodium-ion Batteries", CR2032 coin cells were assembled in a dry glove box filled with argon gas, using the aforementioned carbon anode electrode as the working electrode, metallic sodium as the counter electrode, 1 mol / L NaPF6 EC / DEC (volume ratio 1:1) as the electrolyte, and glass fiber as the separator. Electrochemical performance tests were conducted at room temperature in the voltage range of 0.001-2.0V, and the charge / discharge test current density was 0.1C.

[0066] The performance of each embodiment and comparative example was tested as follows:

[0067] The physicochemical parameters of the materials were characterized, and the degree of disorder was characterized using Raman spectroscopy. The specific surface area was measured using ASAP2020. The specific surface areas of the carbon anode materials obtained in each embodiment and comparative example are shown in Table 1 below. It can be seen that the specific surface areas of Examples 1-6 are smaller. The Raman spectra of the carbon materials in Example 1 and Comparative Example 6 are shown below. Figure 1 As shown, from Figure 1 As can be seen from this, the introduction of sodium tripolyphosphate greatly improves the amorphous carbon structure in carbon materials (1580 cm⁻¹). -1 The disorder of the carbon diffraction peaks changes from a broad peak in Comparative Example 6 to a narrow peak, indicating a transformation from an amorphous carbon structure to a locally ordered structure. This facilitates the migration of sodium ions, reduces the specific surface area of ​​the material, and thus improves the first-cycle coulombic efficiency and specific capacity. Carbon materials have a smaller specific surface area and a 002 diffraction peak spacing exceeding 0.38 nm. Consequently, when used as a negative electrode material in sodium-ion batteries, these materials exhibit extremely high first-cycle coulombic efficiency but poor cycle performance.

[0068] The metal elements (mainly iron, chromium, nickel, zinc and cobalt) in the carbon anode materials obtained in each embodiment and comparative example were detected by inductively coupled plasma mass spectrometry.

[0069] Electrochemical performance testing: To test the performance of the sodium-ion battery anode material of the carbon anode material of the present invention, the method of Example 1 above was used to test each of Examples 1-6 and Comparative Examples 1-4, and the test results are shown in Table 1.

[0070] The test results are shown in Table 1 below:

[0071] Table 1 Test results of the examples and comparative examples

[0072]

[0073] As can be seen from the table above, the solution adopted in this invention can obtain carbon materials with low specific surface area while ensuring the reduction of magnetic metal impurities, thereby ensuring its high first-cycle coulombic efficiency and cycle stability.

[0074] The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0075] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0076] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing a high-capacity sodium-ion battery carbon anode material, characterized in that, Includes the following steps: S1. Crush the petroleum coke to the target particle size, then mix it with hydrochloric acid, stir at a constant temperature for t1, then add a certain mass of sodium tripolyphosphate aqueous solution x, continue stirring at a constant temperature for t2, filter and wash to obtain precursor powder. S2. The precursor powder is mixed with an aqueous solution of sodium tripolyphosphate containing glucose, spray-dried, and then mixed with high softening point asphalt for fusion granulation. Finally, it is subjected to gradient heating treatment under an inert atmosphere. The resulting material is depolymerized and demagnetized to obtain carbon anode material.

2. The method for preparing the high-capacity sodium-ion battery carbon anode material according to claim 1, characterized in that, The petroleum coke mentioned in step S1 is a black solid coke produced by a coking unit from vacuum residue of petroleum; the target particle size of the petroleum coke is D50 = 2-5 μm.

3. The method for preparing the high-capacity sodium-ion battery carbon anode material according to claim 1, characterized in that, The ratio of petroleum coke to hydrochloric acid used in step S1 is (400-600) g : (0.5-2) L; Hydrochloric acid has a pH of 1 and a concentration of 0.05–0.15 mol / L. Sodium tripolyphosphate aqueous solution x is a mixture of α-type sodium tripolyphosphate and water at a mass ratio of 6 to 13:100; the mass ratio of α-type sodium tripolyphosphate to petroleum coke is 5 to 10:

100.

4. The method for preparing the high-capacity sodium-ion battery carbon anode material according to claim 1, characterized in that, The conditions for constant temperature stirring t1 in step S1 are: in a closed reaction vessel, under an oxygen atmosphere, at 20-40℃, with a stirring rate of 50-200 r / min and a stirring time of 1-3 h; The conditions for constant temperature stirring t2 are: in a closed reaction vessel, under an oxygen atmosphere, at 40-100℃, with a stirring rate of 50-200 r / min and a stirring time of 1-4 h.

5. The method for preparing the high-capacity sodium-ion battery carbon anode material according to claim 1, characterized in that, Step S1, filtration and washing, involves washing the filter multiple times with deionized water until the pH of the filtrate is ≤10.

6. The method for preparing the high-capacity sodium-ion battery carbon anode material according to claim 1, characterized in that, The sodium tripolyphosphate aqueous solution y containing glucose in step S2 is a mixture of glucose, sodium β-tripolyphosphate and deionized water in a mass ratio of 1-5:3-13:

100.

7. The method for preparing the high-capacity sodium-ion battery carbon anode material according to claim 1, characterized in that, In step S2, the precursor powder and the sodium tripolyphosphate aqueous solution containing glucose are mixed uniformly at a mass ratio of 100:150-250 to form mixture A.

8. The method for preparing the high-capacity sodium-ion battery carbon anode material according to claim 1, characterized in that, In step S2, spray drying is performed on mixture A. Under the conditions of inlet temperature of 200-250℃ and outlet temperature <105℃, powder particles are obtained by spray drying. These particles are uniformly mixed with high softening point asphalt at a mass ratio of 100:10-20 to obtain mixture B. Mixture B is loaded into a graphite sagger and subjected to gradient heating treatment at a heating rate of 2℃ / min-10℃ / min, heated to 650℃ (T1), held at the temperature for 2-6 hours, and then heated to 900-1200℃ (T2) at a rate of 2-5℃ / min, held at the temperature for 4-12 hours.

9. A high-capacity sodium-ion battery carbon anode material prepared by the method described in any one of claims 1-8.

10. An application of the high-capacity sodium-ion battery carbon anode material as described in claim 9, characterized in that, The carbon anode material is used as the anode material for sodium-ion secondary batteries.

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