A hard carbon material, a preparation method and application thereof, and a sodium ion battery negative electrode material

Abstract

The application relates to the technical field of energy storage, and discloses a hard carbon material, a preparation method and application thereof, and a sodium ion battery negative electrode material, which comprises the following steps: (1) heating and melting a textile material to obtain a molten coating precursor; (2) performing first calcination treatment on the molten coating precursor in the presence of a protective atmosphere I to obtain a pre-carbonized material; (3) performing acid immersion treatment on the pre-carbonized material to obtain an acid-washed material; and (4) performing second calcination treatment on the acid-washed material in the presence of a protective atmosphere II to obtain a hard carbon material. The preparation method provided by the application has high hard carbon material yield, and the hard carbon material has more excellent conductivity and stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, in particular to a hard carbon material, a preparation method and application thereof, and a sodium ion battery negative electrode material. BACKGROUND

[0002] Sodium ion batteries are similar to lithium ion batteries, and are a rocking chair type battery. Thanks to the abundant reserves of sodium resources and the high safety and excellent low-temperature performance of sodium ion batteries, sodium ion batteries are considered a good supplement to lithium ion batteries. Sodium ion batteries have thus ushered in unprecedented development, and hard carbon is considered an effective negative electrode active material for sodium ion batteries. However, the hard carbon process route is long, the product index is strict, the structure-activity relationship is complex, and the performance of the hard carbon material is largely dependent on the properties of the precursor itself. Currently, no precursor and preparation method that meets industrialization has been found, which greatly affects the industrialization of sodium ion batteries.

[0003] Worldwide, about 150 million tons of waste textiles are generated annually, and the waste textiles in China can reach more than 26 million tons. The stock of waste textiles in China has already exceeded 200 million tons. However, most of them are either burned or buried, seriously polluting the atmosphere, surface water and groundwater. This is a great waste of resources.

[0004] Textiles are mainly woven from various fibers, including cotton, hemp, wool, silk, chemical fibers, etc. Chemical fibers include polyester fibers, nylon, acrylic, acrylonitrile, polyimide, flax, and polyester. They are all high molecular materials, and most of them contain N elements, which are good raw materials for preparing hard carbon materials. And the price of each ton of waste textiles is around 800 yuan, which is comparable to cheap biomass. Using waste textiles to prepare high-performance hard carbon meets the requirements of sustainable development and has the prospect of industrialization.

[0005] CN116705999A discloses a preparation method of a hard carbon-based negative electrode material for sodium ion batteries based on waste fabric reutilization. The hard carbon is prepared from waste fabric, including: (1) waste fabric pretreatment; (2) waste fabric pre-pyrolysis; (3) pyrolysis of waste fabric; and then the prepared hard carbon material is used as a negative electrode material for sodium ion batteries. Although this method also uses waste textiles to prepare hard carbon materials, the textile material of the prior art has a high loss on ignition, the yield of the hard carbon material is low, and the conductivity and stability of the hard carbon material itself need to be further improved. SUMMARY

[0006] The purpose of the present application is to provide a hard carbon material with excellent conductivity and stability and a hard carbon material preparation method with higher product yield.

[0007] In order to achieve the above object, the first aspect of the present application provides a method for preparing a hard carbon material, comprising the following steps:

[0008] (1) heating and melting a textile material to obtain a melt-coated precursor; the content of hetero-elements in the textile material is 1-10 wt%; the size of the textile material meets the requirement of passing through a 100-mesh Chinese standard sieve but not passing through a 500-mesh Chinese standard sieve;

[0009] (2) performing a first calcination treatment on the melt-coated precursor in the presence of a protective atmosphere I to obtain a pre-carbonized material;

[0010] (3) performing an acid immersion treatment on the pre-carbonized material to obtain an acid-washed material;

[0011] (4) performing a second calcination treatment on the acid-washed material in the presence of a protective atmosphere II to obtain a hard carbon material;

[0012] In step (1), the textile material comprises component A and component B, and the content mass ratio of the component A and the component B is 1:0.05-19;

[0013] The component A is selected from at least one of polyester fiber, polyamide fiber, polyacrylonitrile fiber, polyvinyl acetal fiber, polypropylene fiber, polyethylene fiber, polyurethane fiber, polybutyrolactone fiber, polyether fiber, and polyimide fiber;

[0014] The component B is selected from at least one of pure cotton fabric, hemp fabric, wool fabric, and silk fabric.

[0015] The second aspect of the present application provides a hard carbon material prepared by the method of the first aspect.

[0016] The third aspect of the present application provides an application of the hard carbon material of the second aspect in the field of sodium ion batteries.

[0017] The fourth aspect of the present application provides a sodium ion battery negative electrode material, which comprises a conductive agent, sodium carboxymethyl cellulose, styrene-butadiene rubber, and the hard carbon material of the second aspect.

[0018] The technical solution provided by the present application has at least the following advantages:

[0019] (1) The technical solution provided by the present application makes full use of the advantages of different types of textile materials, uses hetero-elements to make the hard carbon material have better conductivity, and uses a melt-coating method to make the hard carbon material have a more stable surface after carbonization, which is conducive to improving the overall cycle stability of the material and even the battery.

[0020] (2) After obtaining the pre-carbonized material, the present invention also uses acid treatment to remove the metals and impurities therein, which can significantly improve the product yield and product quality.

[0021] (3) The technical solution provided by this invention preferably uses waste textile materials as raw materials, which are green and environmentally friendly, widely available, and low in cost, and can meet the needs of large-scale industrial production. Ultimately, it realizes the low-cost, large-scale preparation of high-performance hard carbon materials, which can be used to make sodium-ion battery anode materials, thus helping to promote the industrialization of sodium-ion batteries. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the classification methods for textile materials;

[0023] Figure 2 This is the XRD pattern of the hard carbon material prepared in Example 2 of this invention;

[0024] Figure 3 This is a high-magnification transmission image of the hard carbon material prepared in Example 2 of this invention;

[0025] Figure 4 This is the first charge-discharge curve of the sodium-ion battery prepared using the hard carbon material of Example 2 according to the present invention. Detailed Implementation

[0026] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0027] As previously described, a first aspect of the present invention provides a method for preparing hard carbon materials, comprising the following steps:

[0028] (1) The textile material is heated and melted to obtain a melt-coated precursor; the content of impurity elements in the textile material is 1-10 wt%; the size of the textile material is such that it can pass through a 100-mesh Chinese standard sieve but cannot pass through a 500-mesh Chinese standard sieve.

[0029] (2) Under the presence of a protective atmosphere I, the molten coated precursor is subjected to a first calcination treatment to obtain a pre-carbonized material;

[0030] (3) The pre-carbonized material is subjected to acid immersion treatment to obtain pickled material;

[0031] (4) Under the presence of protective atmosphere II, the pickled material is subjected to a second calcination treatment to obtain hard carbon material;

[0032] wherein, in step (1), the textile material comprises component A and component B, and the content mass ratio of the component A and the component B is 1:0.05-19;

[0033] The component A is selected from at least one of polyester fiber, polyamide fiber, polyacrylonitrile fiber, polyvinyl acetal fiber, polypropylene fiber, polyethylene fiber, polyurethane fiber, polybutyrolactone fiber, polyether fiber, and polyimide fiber.

[0034] The component B is selected from at least one of pure cotton fabric, hemp fabric, wool fabric, and silk fabric.

[0035] Preferably, the size of the textile material meets the requirement of being able to pass through a 200-mesh Chinese standard sieve but not a 400-mesh Chinese standard sieve.

[0036] The high molecular material in the component A can be converted into a flowable liquid state by heating, and is a meltable fiber.

[0037] Preferably, the method further comprises, before step (1), classifying and crushing the textile to be treated to obtain a textile material precursor, then mixing different kinds of the textile material precursor to obtain the textile material, and then performing the heating and melting treatment on the textile material.

[0038] Preferably, the textile to be treated is classified in the manner shown in the table. Figure 1 The textile to be treated is first classified into textile containing meltable fiber (named as ZR, such as cotton-polyamide fiber mixed fabric and polyamide fiber-polyimide fiber mixed fabric) and textile not containing meltable fiber (named as ZB, such as pure cotton fabric, hemp fabric, and silk fabric); then the ZR is classified into textile containing meltable fiber and containing impurities (named as ZRZ, such as polyamide fiber-polyimide fiber mixed fabric) and textile containing meltable fiber but not containing impurities (named as ZRB, such as polyester fiber fabric); and the ZB is classified into textile not containing meltable fiber but containing impurities (named as ZBZ, such as wool fabric) and textile not containing meltable fiber and not containing impurities (named as ZBB, such as pure cotton fabric).

[0039] Preferably, in step (1), the textile material is a combination of polyimide fibers and pure cotton fabric, and the content weight ratio of the polyimide fibers and the pure cotton fabric is 1:1-9, more preferably 1:2-5. The inventors of the present application have found in research that the hard carbon material prepared by using the textile material under the more preferred conditions as raw material has more excellent conductivity and stability, and can significantly improve the cycle stability of the battery when used in the battery.

[0040] Preferably, in step (1), the temperature of the heating and melting is 150-330℃.

[0041] More preferably, in step (1), the temperature of the heating and melting is 220-300℃, and the time is 1-3h. The inventors of the present application have found in research that under the more preferred conditions, the present application can prepare a hard carbon material with better conductivity and stability.

[0042] By using the processing conditions of the heating and melting provided by the present application, the effect of the high molecular material being melted under the action of heating and coated on the surface of the high molecular material that cannot be melted can be achieved, so that the high molecular material is crosslinked to obtain the melt-coated precursor.

[0043] Preferably, in step (2), the conditions of the first calcination treatment include: the temperature is 350-600℃, the time is 0.5-2h, and the temperature rising rate is 5-20℃ / min.

[0044] Preferably, in step (2), the protective atmosphere I is nitrogen and / or argon, and the flow rate of the protective atmosphere I is 10-50mL / min.

[0045] According to one preferred specific embodiment, in step (3), the acid solution used for the acid immersion treatment is a hydrochloric acid solution and / or a sulfuric acid solution, and the concentration of hydrogen ions in the acid solution is 1-6mol / L, preferably 1-3mol / L.

[0046] According to another preferred specific embodiment, the method of step (3) of the present application further comprises: after the acid immersion treatment of the pre-carbonized material, an acid immersion material is obtained, and then the acid immersion material is sequentially subjected to washing, filtering and drying treatment to obtain the acid washing material.

[0047] Preferably, the acid immersion material is washed by using deionized water until the ion conductivity of the filtered water obtained by filtering is less than 0.1μS / cm, and then the drying treatment is performed.

[0048] More preferably, the drying treatment is vacuum drying and / or spray drying.

[0049] The acid leaching and washing operation provided by the present application can remove impurity elements such as metal elements, and can avoid the increase of macropores and interconnected pores, reduce the corrosion of metal elements to carbon in the subsequent carbonization process, reduce the formation of monatomic metal complexes (reduce electrocatalytic reaction, improve the stability of the electrochemical window), not only can improve the yield of hard carbon material, but also can significantly improve the quality of hard carbon material.

[0050] Preferably, in step (4), the conditions of the second calcination treatment include: temperature of 700-1700℃, more preferably 1100-1400℃; time of 1-4h, more preferably 2-3h; heating rate of 1-5℃ / min.

[0051] Preferably, in step (4), the protective atmosphere II is nitrogen and / or argon, and the flow rate of the protective atmosphere II is 10-30mL / min.

[0052] Preferably, the temperature of the second calcination treatment is 500-800℃ higher than the temperature of the first calcination treatment. The inventors of the present application found in the research that the hard carbon material prepared under the preferred conditions has more excellent conductivity and stability, and can significantly improve the cycle stability of the battery when used in the battery.

[0053] The time of the first calcination treatment and the second calcination treatment of the present application is counted from the temperature rising to the specified temperature, and does not include the temperature rising time.

[0054] The present application does not have special restrictions on the equipment used for the first calcination treatment and the second calcination treatment, and those skilled in the art can select according to the equipment known in the art, for example, a tubular furnace, which will not be described here again, and those skilled in the art should not be understood as a limitation of the present application.

[0055] As described above, the second aspect of the present application provides a hard carbon material prepared by the method of the first aspect.

[0056] Preferably, the hard carbon material contains 0.1-3wt% of impurity elements in terms of elements, and the impurity elements are the remaining elements in the hard carbon material except for carbon elements.

[0057] Preferably, the impurity elements are selected from at least one of N, F, P, S, Cl, Se.

[0058] The technical scheme provided by the application realizes pre-coating by a melting method, the outer edge structure of the hard carbon material is regulated in a subsequent pyrolysis process, electrolyte activity of the hard carbon material is reduced, side reactions are reduced, the cycle performance of the material is improved, metal elements such as dyeing agents are removed in advance by acid treatment, carbon corrosion is reduced, water is passed to reduce the specific surface area of the material, thereby improving the purity and yield of the hard carbon material, and finally high specific capacity and initial efficiency are realized.

[0059] As described above, the third aspect of the application provides an application of the hard carbon material of the foregoing second aspect in the field of sodium ion batteries.

[0060] As described above, the fourth aspect of the application provides a sodium ion battery negative material, which contains: a conductive agent, sodium carboxymethyl cellulose, styrene-butadiene rubber, and the hard carbon material of the foregoing second aspect.

[0061] Preferably, the mass ratio of the hard carbon material, the conductive agent, the sodium carboxymethyl cellulose, and the styrene-butadiene rubber is 90:3-5:2-4:2-4.

[0062] The application will be described in detail below by way of examples. In the following examples, the raw materials are all commercially available products, and the room temperature refers to 25±2℃, unless otherwise specified.

[0063] Before performing each example, the polyimide fiber waste fabric is first crushed, sieved, and materials with a size capable of passing through a 200-mesh Chinese standard sieve but not capable of passing through a 400-mesh Chinese standard sieve are obtained; the pure cotton fabric is crushed, sieved, and materials with a size capable of passing through a 200-mesh Chinese standard sieve but not capable of passing through a 400-mesh Chinese standard sieve are obtained; then, the required amount is weighed and the following example is operated.

[0064] Preparation Example 1

[0065] (1) 2 g of the crushed polyimide fiber waste fabric and 18 g of the crushed pure cotton fabric are stirred and mixed to obtain a textile material, and then the textile material is placed in an oven and heated and melted at 280℃ for 2 h to obtain a melt-coated precursor;

[0066] (2) After the melt-coated precursor is cooled to room temperature, it is transferred to a tube furnace and subjected to a first calcination treatment (temperature: 550℃, time: 2 h, and heating rate: 5℃ / min) under an argon atmosphere (flow rate: 40 mL / min) to obtain a pre-carbonized material;

[0067] (3) After the pre-carbonized material is cooled to room temperature, it is soaked in a 1 mol / L hydrochloric acid solution for 12 h, washed with deionized water until the filtered water ion conductivity is lower than 0.1 μS / cm, and then transferred to a vacuum drying oven for drying at 105°C for 12 h to obtain an acid-washed material;

[0068] (4) The acid-washed material is transferred to a tube furnace for a second calcination treatment under an argon atmosphere (flow rate: 20 mL / min) at a temperature of 1300°C for 3 h and a heating rate of 3°C / min, and then cooled to room temperature to obtain a hard carbon material.

[0069] Preparation Example 2-10

[0070] A similar procedure to Preparation Example 1 is used, except that the textile material, the temperature for heating and melting, the temperature for the first calcination treatment, and the temperature for the second calcination treatment are different, as listed in Table 1.

[0071] A hard carbon material is prepared.

[0072] Comparative Preparation Example 1

[0073] A similar procedure to Preparation Example 2 is used, except that the type of textile material is changed, and 4 g of polyimide fiber waste fabric and 16 g of pure cotton fabric are replaced by 20 g of pure cotton fabric.

[0074] A hard carbon material is prepared.

[0075] Comparative Preparation Example 2

[0076] A similar procedure to Preparation Example 2 is used, except that the heating and melting treatment is not performed, and the textile material is directly subjected to the first calcination treatment. Specifically:

[0077] (1) 4 g of crushed polyimide fiber waste fabric and 16 g of broken pure cotton fabric are stirred and mixed to obtain a textile material.

[0078] (2) The textile material is transferred to a tube furnace for a first calcination treatment under an argon atmosphere at a temperature of 550°C for 2 h and a heating rate of 5°C / min to obtain a pre-carbonized material.

[0079] (3) After the pre-carbonized material is cooled to room temperature, it is soaked in a 1 mol / L hydrochloric acid solution for 12 h, washed with deionized water until the filtered water ion conductivity is lower than 0.1 μS / cm, and then transferred to a vacuum drying oven for drying at 105°C for 12 h to obtain an acid-washed material.

[0080] (4) The acid-washed material was transferred to a tube furnace and subjected to a second calcination treatment (temperature of 1300 °C, time of 3 h, and heating rate of 3 °C / min) under an argon atmosphere, and after being cooled to room temperature, a hard carbon material was obtained.

[0081] Comparative Preparation Example 3

[0082] A similar procedure to that of Preparation Example 2 was used, except that the first calcination treatment was not performed, and the melt-coated precursor was directly subjected to a second calcination treatment; specifically:

[0083] (1) 4 g of a pulverized polyimide fiber waste fabric and 16 g of a broken pure cotton fabric were stirred and mixed to obtain a textile material, and then the textile material was heated and melted in an oven at 280 °C for 2 h to obtain a melt-coated precursor;

[0084] (2) After the melt-coated precursor was cooled to room temperature, it was immersed in a 1 mol / L hydrochloric acid solution for 12 h, washed with deionized water until the ion conductivity of the filtered water was less than 0.1 μS / cm, and then transferred to a vacuum drying oven and dried at 105 °C for 12 h to obtain an acid-washed material;

[0085] (3) The acid-washed material was transferred to a tube furnace and subjected to a second calcination treatment (temperature of 1300 °C, time of 3 h, and heating rate of 3 °C / min) under an argon atmosphere, and after being cooled to room temperature, a hard carbon material was obtained.

[0086] Comparative Preparation Example 4

[0087] A similar procedure to that of Preparation Example 2 was used, except that the acid immersion treatment was not performed, and the pre-carbonized material was directly subjected to a second calcination treatment; specifically:

[0088] (1) 4 g of a pulverized polyimide fiber waste fabric and 16 g of a broken pure cotton fabric were stirred and mixed to obtain a textile material, and then the textile material was heated and melted in an oven at 280 °C for 2 h to obtain a melt-coated precursor;

[0089] (2) After the melt-coated precursor was cooled to room temperature, it was transferred to a tube furnace and subjected to a first calcination treatment (temperature of 550 °C, time of 2 h, and heating rate of 5 °C / min) under an argon atmosphere to obtain a pre-carbonized material;

[0090] (3) The pre-carbonized material was subjected to a second calcination treatment (temperature of 1300 °C, time of 3 h, and heating rate of 3 °C / min) under an argon atmosphere, and after being cooled to room temperature, a hard carbon material was obtained.

[0091] Comparative Preparation Example 5

[0092] The similar procedure of Preparation Example 2 was adopted, except that the pure cotton fabric was replaced by cotton of the same mass, to prepare the hard carbon material.

[0093] Since the cotton is a material that has not been spun after twisting, the cotton fiber is extremely fine, and the particle size after crushing cannot meet the requirements of the present application. In the preparation of the hard carbon material, the coating effect of the molten coating precursor is poor, thus the loss on ignition of the textile material is high, the yield of the hard carbon material product is low, and the specific surface area of the hard carbon material is also too large, thereby affecting the electrical conductivity and stability of the material.

[0094] Comparative Preparation Example 6

[0095] The similar procedure of Preparation Example 2 was adopted, except that the type of textile material was changed, and the combination of 4 g of polyimide fiber waste fabric and 16 g of pure cotton fabric was replaced by 20 g of polyamide fiber fabric; to prepare the hard carbon material.

[0096] Comparative Preparation Example 7

[0097] The similar procedure of Preparation Example 2 was adopted, except that the type of textile material was changed, and the combination of 4 g of polyimide fiber waste fabric and 16 g of pure cotton fabric was replaced by 20 g of wool fabric; to prepare the hard carbon material.

[0098] The content of the meltable fiber in the textile material and the parameters and yield of the prepared hard carbon material are shown in Table 2.

[0099] The yield of the hard carbon material η (%) = the mass of the obtained hard carbon material (m1) / the mass of the textile material input (m2) x 100%.

[0100] Figure 2 is the X-ray diffraction (XRD) spectrum of the hard carbon material obtained in Preparation Example 2 of the present application, from which it can be seen that there is a broad graphitization crystallization peak corresponding to the hard carbon material.

[0101] Figure 3 is the high-magnification transmission electron micrograph of the hard carbon material obtained in Preparation Example 2 of the present application, in which d = 0.38 nm refers to the lattice spacing of the graphitized microcrystal, which mainly affects the sodium storage capacity of the hard carbon material. This lattice spacing is conducive to the reversible embedding and extraction of Na + From the figure, it can be seen that the hard carbon obtained in Preparation Example 2 has abundant graphitized microcrystals, and the lattice spacing is suitable, which is conducive to improving the specific capacity of the hard carbon material.

[0102] Table 1

[0103]

[0104]

[0105] Table 2

[0106]

[0107] Example 1

[0108] The hard carbon material prepared in Preparation Example 1 was used to prepare a negative electrode material:

[0109] According to the mass ratio of hard carbon material: conductive agent: sodium carboxymethyl cellulose: butadiene rubber = 90:4:3:3, a negative electrode slurry was prepared with deionized water, and the coating thickness was controlled at 150 μm. The negative electrode slurry was coated on an aluminum foil, and then dried in an oven at 100°C for 2 h. Then, the negative electrode sheet was cut using a sheet cutter.

[0110] Examples 2-10

[0111] The same process as in Example 1 was used, except that the hard carbon material of Preparation Example 1 was replaced with an equal amount of the hard carbon material of Preparation Examples 2-10 in sequence, to prepare a negative electrode sheet. See Table 3 for details.

[0112] Comparative Examples 1-7

[0113] The same process as in Example 1 was used, except that the hard carbon material of Preparation Example 1 was replaced with an equal amount of the hard carbon material of Comparative Preparation Examples 1-7 in sequence, to prepare a negative electrode sheet. See Table 3 for details.

[0114] Test Example 1

[0115] NaPF6: sodium hexafluorophosphate; EC: ethylene carbonate; DMC: dimethyl carbonate

[0116] The negative electrode sheets prepared in the foregoing examples and comparative examples were used as the negative electrode sheets of sodium ion batteries, and metal sodium sheets were used as the positive electrode sheets. The electrolyte was 1 mol / L NaPF6-EC / DMC (solvent EC: DMC = 1:1, volume ratio), and CR2032 button cells were assembled in a glove box. Then, the discharge program was 0.1C to 0V, and the cell was rested for 10 min. The charge program was 0.1C to 2.0V, and the sodium ion battery was subjected to charge and discharge tests.

[0117] The results are shown in Table 3.

[0118] Table 3

[0119]

[0120]

[0121] Figure 4It is the first charge-discharge curve of the sodium ion battery prepared by using the hard carbon material of the preparation example 2 of the application, and it can be seen from the figure that the hard carbon material has high discharge specific capacity and first charge-discharge efficiency.

[0122] It can be seen from the above results that the hard carbon preparation method disclosed by the application has wide raw material source range, high yield, and more excellent conductivity and stability, and the hard carbon material has the characteristics of high first efficiency, excellent rate performance and good cycle stability when applied to a sodium ion battery. The technical scheme disclosed by the application has good commercial application prospect.

[0123] The preferred embodiments of the application are described in detail above, but the application is not limited thereto. Within the technical concept of the application, various simple modifications can be made to the technical scheme of the application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the application and belong to the protection scope of the application.

Claims

1. A method of producing a hard carbon material, characterized by, Comprising the following steps: (1) heating and melting a textile material to obtain a melt-coated precursor; the content of impurity elements in the textile material is 1-10 wt%; the size of the textile material meets the requirement of passing through a 100-mesh Chinese standard sieve but not a 500-mesh Chinese standard sieve; (2) subjecting the melt-coated precursor to a first calcination treatment in the presence of a protective atmosphere I to obtain a pre-carbonized material; (3) subjecting the pre-carbonized material to an acid immersion treatment to obtain an acid-washed material; (4) subjecting the acid-washed material to a second calcination treatment in the presence of a protective atmosphere II to obtain a hard carbon material; In step (1), the textile material comprises component A and component B, and the content mass ratio of the component A to the component B is 1:0.05-19; The component A is at least one selected from polyester fiber, polyamide fiber, polyacrylonitrile fiber, polyvinyl acetal fiber, polypropylene fiber, polyethylene fiber, polyurethane fiber, polybutyrolactone fiber, polyether fiber, and polyimide fiber; The component B is at least one selected from pure cotton fabric, hemp fabric, wool fabric, and silk fabric.

2. The method of claim 1, wherein, In step (1), the textile material is a combination of polyimide fiber and pure cotton fabric, and the content weight ratio of the polyimide fiber to the pure cotton fabric is 1:1-9.

3. The method according to claim 1 or 2, characterized in that, In step (1), the temperature of the heating and melting is 150-330℃.

4. The method according to claim 1 or 2, characterized in that, In step (2), the first calcination treatment is performed under conditions including a temperature of 350-600℃, a time of 0.5-2h, and a temperature rising rate of 5-20℃ / min. In step (2), the protective atmosphere I is nitrogen and / or argon, and the flow rate of the protective atmosphere I is 10-50 mL / min.

5. The method according to claim 1 or 2, characterized in that, In step (3), the acid solution used for the acid immersion treatment is a hydrochloric acid solution and / or a sulfuric acid solution, and the concentration of hydrogen ions in the acid solution is 1-6 mol / L.

6. The method of claim 1 or 2, wherein, In step (4), the second calcination treatment is performed under conditions including a temperature of 700-1700℃, a time of 1-4h, and a temperature rising rate of 1-5℃ / min. In step (4), the protective atmosphere II is nitrogen and / or argon, and the flow rate of the protective atmosphere II is 10-30 mL / min.

7. The method according to claim 1 or 2, characterized in that, The temperature of the second calcination treatment is 500-800℃ higher than that of the first calcination treatment.

8. A hard carbon material prepared by the method of any one of claims 1-7.

9. Use of the hard carbon material of claim 8 in the field of sodium ion batteries.

10. A sodium-ion battery anode material, characterized in that, The sodium ion battery anode material comprises a conductive agent, sodium carboxymethyl cellulose, butadiene-styrene rubber, and the hard carbon material of claim 8.

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