A high-performance resin-based hard carbon negative electrode material and its preparation method and application

Abstract

The present invention belongs to the technical field of sodium ion battery electrode materials, and specifically relates to a high-performance resin-based hard carbon negative electrode material, a preparation method thereof, and an application thereof. The particle matrix in the hard carbon negative electrode material prepared by the present invention has a relatively large porous structure. When the resin-based hard carbon negative electrode material is used for the negative electrode of a sodium ion battery, it has a large number of porous structures and a fixed chemical composition, and can improve the diffusion kinetics and storage capacity of sodium ions in the hard carbon in the battery, thereby improving the rate performance and power density of the sodium ion battery. The method of the present invention has cheap raw materials, a simple and safe manufacturing process, and high commercial value. The hard carbon negative electrode material prepared by the present invention, when used as the negative electrode of a sodium ion battery, has low raw material cost and is pollution-free. The obtained negative electrode specific capacity and rate performance are improved, and can be used for high-performance sodium ion batteries.

Description

Technical Field

[0001] The present invention belongs to the technical field of sodium ion battery electrode materials, and specifically relates to a high-performance resin-based hard carbon negative electrode material and a preparation method and application thereof. Background Art

[0002] Fossil fuels have brought tremendous progress to civilized society, but their excessive use has also led to serious energy crises and environmental pollution. With the global overconsumption of fossil fuels and the growing severity of environmental problems, energy storage technologies have rapidly developed in recent years. Chemical energy storage technologies, in particular, have gained widespread adoption due to their advantages such as short construction cycles, flexibility, ease of use, and adjustable capacity. With the widespread use of lithium-ion batteries in various electronic products, such as electric vehicles, mobile phones, and computers, the demand for lithium has increased year by year. However, global lithium reserves are extremely limited, unevenly distributed, and costly, severely restricting the development of low-cost, high-performance energy storage devices.

[0003] Sodium and lithium are elements of the same family. Sodium has similar electrochemical properties to lithium, and is abundant in reserves and low in cost. Therefore, sodium-ion batteries (SIBs) are the next generation of commercially available secondary batteries after lithium-ion batteries (LIBs), and are considered to be the best energy storage devices to replace lead-acid batteries and supplement lithium-ion batteries. These advantages make sodium-ion batteries have extremely high application prospects in fields such as large-scale energy storage, and are an important technology for solving the "bottleneck" problem of resources and achieving the "dual carbon" goals.

[0004] Traditional carbon negative electrode materials mainly include artificial graphite, natural graphite, mesophase carbon microspheres, soft carbon, hard carbon, etc. Among them, hard carbon is difficult to graphitize carbon, which has the advantages of random order, cheap raw materials, wide source of raw materials, stable structure, long charge and discharge cycle life, and better safety performance. However, the hard carbon negative electrode materials in the existing technology still have the capacity (200-300mAh g -1 ), poor rate performance, low rapid sodium insertion / extraction ability, and poor charging performance of hard carbon negative electrode materials.

[0005] Common sodium-ion batteries use hard carbon materials, transition metals and their alloy compounds as negative electrodes, and polyanions, Prussian blue, layered oxides and other materials as positive electrodes.

[0006] Currently, hard carbon anode materials for sodium-ion batteries are primarily prepared using biomass precursors, such as coconut shells, straw, pollen, and bamboo. Specifically, biomass is often used as the carbon source. However, due to the lack of qualitative raw material analysis, chemical composition differences between different raw materials, and the instability of the raw material's chemical composition, stable, large-scale mass production is difficult, and the subsequent impurity removal process is also complex.

[0007] In related research, although some scholars have used hard carbon precursors with fixed chemical compositions such as glucose, the prepared hard carbon materials have a single microstructure and cannot achieve high reversible storage of sodium ions. In addition, the diffusion kinetics of sodium ions in such hard carbons are slow, that is, the ion transport path is long and the transport speed is slow, resulting in poor rate performance and short cycle life of the assembled battery. In addition, a Chinese patent with publication number CN116873898A discloses a hard carbon negative electrode material for sodium ion batteries, which is obtained by reacting resorcinol, a template, an ethanol aqueous solution, and a formaldehyde solution to obtain a resin gel, which is then calcined and mixed with g-C3N4 and ground to obtain a hard carbon negative electrode material. Although rich microporous structure, high reversible capacity and good cyclability can also be obtained, the alkali metal or alkaline earth metal used will cause greater pollution to the environment and is not conducive to recycling.

[0008] Therefore, it is urgent to develop new hard carbon negative electrode materials with high specific capacity, high rate, high safety and suitable for sodium ion batteries. Summary of the Invention

[0009] The present invention addresses the shortcomings of existing technologies by providing a high-performance resin-based hard carbon anode material and its preparation method. The particle matrix of the hard carbon anode material prepared by the present invention has a relatively porous structure. When used as the anode of a sodium-ion battery, this resin-based hard carbon anode material exhibits a large amount of pores and a fixed chemical composition. This material can enhance the diffusion kinetics and storage capacity of sodium ions in the hard carbon, improving the rate capability and power density of the battery.

[0010] Furthermore, the present invention also provides the use of the high-performance resin-based hard carbon negative electrode material as a negative electrode for lithium-ion batteries or sodium-ion batteries.

[0011] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0012] A method for preparing a high-performance resin-based hard carbon negative electrode material comprises the following steps:

[0013] 1) Preparation of precursor solution: Mix the phenol monomer and urotropine, add them to solvent I, and stir and dissolve them for 10-30 minutes to obtain a clear and transparent solution;

[0014] 2) Preparation of precursor: The solution obtained in step 1) is allowed to stand for 8 to 36 hours to obtain a reddish-brown liquid, which is dried once to obtain a reddish-brown solid, which is washed and dried twice to obtain a solid which is the precursor;

[0015] 3) Preliminary grinding and pulverization: Preliminary grinding and pulverization of the precursor solid obtained in step 2) for 30 to 40 minutes;

[0016] 4) Precursor carbonization: The ground precursor solid is placed in a high-temperature furnace for high-temperature carbonization treatment to obtain a product, which is a hard carbon anode material;

[0017] 5) Secondary grinding and crushing: The carbonized hard carbon negative electrode material is subjected to secondary grinding and post-processing to obtain the final product.

[0018] Furthermore, in step 1), the phenol monomer is one or more of hydroquinone, phloroglucinol, and phenol.

[0019] Furthermore, in step 1), the mass ratio of the phenol monomer to the urotropine is (1-6):1.

[0020] Furthermore, in step 1), solvent I is water, ethanol or a mixed solvent of the two; specifically, the volume ratio of water to ethanol in the mixed solvent is (3-4):1; ethanol in the mixed solvent is used as a pore-forming agent and dispersant.

[0021] Further preferably, in step 1), the mass ratio of the phenol monomer, hexamethylenetetramine and solvent I is (1-6) g: 1 g: (25-35) mL.

[0022] Furthermore, in step 2), the first drying is drying in an oven at 70-90° C. overnight (8-16 h); the second drying is drying in an oven at 70-90° C. for 18-24 h.

[0023] Furthermore, in step 4), the high temperature carbonization treatment is carried out at 2-5°C min under a protective atmosphere. -1 The temperature is raised to 700-800℃ at a rate of 1-2℃ min, and kept at this temperature for 20-30min for pre-carbonization treatment; then the temperature is further raised to 700-800℃ at a rate of 1-2℃ min -1 The temperature is raised to 1100℃~1500℃ at a rate of 1~2℃min, and carbonization treatment is carried out under protective atmosphere for 1~2 hours. -1 The temperature is lowered to 700-800℃ at a rate of 2-5℃min -1 The temperature was lowered to 400-500°C at a rapid rate, and finally naturally cooled to room temperature.

[0024] More preferably, the protective atmosphere during the carbonization process is an inert gas such as nitrogen or argon.

[0025] Furthermore, the secondary grinding post-processing in step 5) is: the carbonized hard carbon negative electrode material is first manually ground for 20 to 30 minutes, and then placed in a ball mill and ball milled at a speed of 800 to 1000 r / min for 30 to 60 minutes to crush it into smaller particles.

[0026] Furthermore, the present invention also provides a high-performance resin-based hard carbon negative electrode material prepared by the above method. The particle size distribution of the hard carbon product is 2μm to 38μm, with an average particle size of 11.6μm. It has good capacitance and charge-discharge performance, and can be used as a negative electrode material for the preparation of lithium-ion batteries or sodium-ion batteries.

[0027] Furthermore, based on a general inventive concept, the present invention also provides a method for preparing a composite electrode slurry containing the high-performance resin-based hard carbon negative electrode material, comprising the following steps:

[0028] (1) Weigh a certain amount of active material, conductive agent, and binder, and place them in a container in sequence to obtain a mixed powder;

[0029] (2) Solvent II is added to the mixed powder of step (1), and ultrasonic dispersion is performed at a power of 80 to 100 W for 8 to 12 minutes. Then, a polytetrafluoroethylene magnet is placed in a container and stirred at a speed of 300 to 400 r / min for 8 to 12 hours to uniformly disperse the active material and the conductive agent to obtain a composite electrode slurry.

[0030] Specifically, the active material in step (1) is the high-performance resin-based hard carbon negative electrode material prepared by the above method; the conductive agent is carbon black (Super-P); and the binder is PVDF.

[0031] Specifically, the solvent II is selected from one of deionized water, ethanol and NMP.

[0032] Specifically, the mass of solvent II is 1 to 1.5 times the mass of the mixed powder.

[0033] Specifically, in the composite electrode slurry obtained in step (2), the weight ratio of the active material, the conductive agent, and the binder is (6-8):1:(1-2).

[0034] Furthermore, based on a general inventive concept, the present invention also provides the use of the high-performance resin-based hard carbon negative electrode material or the composite electrode slurry in the preparation of a sodium ion battery.

[0035] Furthermore, the present invention also provides a method for preparing a sodium ion battery using the high-performance resin-based hard carbon negative electrode material or the composite electrode slurry, wherein the high-performance resin-based hard carbon negative electrode material or the composite electrode slurry is prepared into a sodium ion battery negative electrode, specifically comprising the following steps:

[0036] a) Preparation of electrode sheets: The composite electrode slurry prepared by the above method was coated on copper foil (current collector), dried at 60-80°C for 8-12 hours, and then formed into button-type electrode sheets with a diameter of 12 mm.

[0037] b) Button cell assembly: A button cell was assembled using a sodium metal sheet as the counter electrode. The battery model was a CR2032 button cell.

[0038] Specifically, in step b), the diaphragm type is Whatman GF / D, and the main component of the electrolyte used in the battery is sodium salt (sodium hexafluorophosphate); preferably, the electrolyte is NaPF6 in DME with a concentration of 1M.

[0039] Furthermore, based on a general inventive concept, the present invention also provides a sodium ion battery prepared using the high-performance resin-based hard carbon material or the composite electrode slurry.

[0040] Compared with the prior art, the advantages of the present invention are:

[0041] 1. The hard carbon negative electrode materials in the prior art still have low capacity (200-300mAh g -1 ), poor rate performance, low rapid sodium insertion / extraction capabilities, and poor charging performance of hard carbon negative electrode materials. The hard carbon negative electrode material prepared by the present invention has a particle matrix with a relatively large porosity structure, high specific capacity, and good rate performance. When used as the negative electrode of a sodium ion battery, this resin-based hard carbon negative electrode material has a large porosity structure and a fixed chemical composition. It can also improve the diffusion kinetics and storage capacity of sodium ions in the hard carbon in the battery, thereby improving the rate performance and power density of the sodium ion battery.

[0042] 2. The method of the present invention has cheap raw materials, simple and safe production process, and high commercial value.

[0043] 3. The hard carbon negative electrode material prepared by the present invention, when used as the negative electrode of a sodium ion battery, has low raw material cost and is pollution-free. The obtained negative electrode has improved specific capacity and rate performance, and can be used in high-performance sodium ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a flow chart of the method for preparing the high-performance resin-based hard carbon negative electrode material of the present invention;

[0045] Figure 2 This is an SEM image of the high-performance resin-based hard carbon negative electrode material prepared in Example 1;

[0046] Figure 3 The sodium ion battery made of the hard carbon negative electrode material of Examples 1, 2, 3, 4, and 5 is subjected to a current density of 0.1Ag. -1 Cycle performance diagram;

[0047] Figure 4 The hard carbon negative electrode material of Example 1 is -1 The cycling performance diagram of lithium-ion batteries. DETAILED DESCRIPTION

[0048] The following examples will further illustrate the present invention with reference to the accompanying drawings. This embodiment is implemented based on the technical solution of the present invention and provides detailed implementation methods and processes, but the protection scope of the present invention is not limited to the following examples.

[0049] The experimental methods in the following examples without specific conditions are generally based on conventional conditions, and the raw materials and reagents used are conventional commercial products unless otherwise specified.

[0050] The specification of resorcinol is 99% (AR); the manufacturer is Shanghai Aladdin Reagent Co., Ltd.

[0051] The specification of methenamine is 99.5% (AR); the manufacturer is Beijing Yinuokai Technology Co., Ltd.

[0052] Example 1

[0053] Example 1 provides a method for preparing a high-performance resin-based hard carbon negative electrode material, as shown in the flow chart. Figure 1 As shown, the specific steps are:

[0054] 1) Preparation of a precursor solution: 1.16 g of resorcinol and 0.432 g of hexamethylenetetramine were mixed and added to 12.85 mL of a mixed solvent of water and ethanol (purity >99.5%, AR) and stirred for 30 minutes to obtain a clear solution; the volume ratio of water to ethanol in the mixed solvent was 7:2; the ethanol served as a pore-forming agent and dispersant;

[0055] 2) Preparation of Precursor: The solution obtained in step 1) was placed in a Petri dish and allowed to stand for 24 hours to obtain a reddish-brown liquid. The liquid was then placed in an oven at 80°C overnight to obtain a reddish-brown solid. The solid was washed several times with ethanol and then dried in an oven at 80°C for 24 hours. The resulting solid was the precursor.

[0056] 3) Preliminary grinding and pulverization: The precursor solid obtained in step 2) is preliminarily manually ground and pulverized for 30 minutes;

[0057] 4) Precursor carbonization: Place the ground precursor solid into a high-temperature furnace and heat it at 5°C min -1 The temperature was raised to 800℃ at a rate of 1000℃ and kept at that temperature for 30min for pre-carbonization treatment; then the temperature was further raised to 800℃ at a rate of 2℃min -1 The temperature was raised to 1300℃ at a rate of 2℃ min-1 and carbonized for 2 hours under protective atmosphere. -1 The temperature was lowered to 800℃ at a rate of 5℃min -1The temperature is lowered to 500°C at a high speed and then naturally lowered to room temperature to obtain a hard carbon negative electrode material; the protective atmosphere during the carbonization process is nitrogen;

[0058] 5) Secondary grinding and crushing (post-grinding treatment of the carbonized hard carbon negative electrode material): The carbonized hard carbon negative electrode material is manually ground for about 30 minutes, and then placed in a ball mill and ball milled at a speed of 1000r / min to crush the hard carbon in the ball mill. The ball milling time is 60 minutes and the material is crushed into smaller particles, which is the final product.

[0059] Figure 2 The SEM image of the product prepared in Example 1 is shown in FIG. Figure 2 It can be seen from the figure that the particle size of the hard carbon product is distributed in the range of 2 μm to 38 μm, with an average particle size of 11.6 μm.

[0060] At the same time, it can be concluded from Example 1 that when the volume ratio of the mixed solvent is ethanol: water = 7:2 (12.85 mL), and the particle size of the product prepared in Example 1 is distributed in the range of 2 μm to 38 μm (the average particle size is 11.6 μm), the specific surface area is 68 m 2 / g, with an average pore size of 0.9nm and a mass specific capacity of ≥420mAh g -1 , the first efficiency is ≥70% (for the test method, see patent document CN116454252A A sodium ion battery negative electrode material and its preparation method).

[0061] Example 2

[0062] Example 2 provides a method for preparing a high-performance resin-based hard carbon negative electrode material. The difference between Example 2 and Example 1 is that in step 2), the solution obtained in step 1) is placed in a culture dish and allowed to stand for 8 hours.

[0063] Example 3

[0064] The difference between Example 3 and Example 1 is that in step 1), the mixed solvent is replaced by water.

[0065] Example 4

[0066] The difference between Example 4 and Example 1 is that the carbonization process in step 4) is as follows: the ground precursor solid is placed in a high-temperature furnace and heated at 5°C min -1 The temperature was raised to 800℃ at a rate of 1000℃ and kept at that temperature for 30min for pre-carbonization treatment; then the temperature was further raised to 800℃ at a rate of 2℃min -1 The temperature was raised to 1100 °C at a rate of 2 °C min-1 and carbonized for 2 h under a protective atmosphere. -1 The temperature was lowered to 800℃ at a rate of 5℃min -1The temperature was then decreased to 500°C at a rate of 0.5 °C and then naturally cooled to room temperature.

[0067] Example 5

[0068] The difference between Example 5 and Example 1 is that the carbonization process in step 4) is as follows: the ground precursor solid is placed in a high-temperature furnace and heated at 5°C min -1 The temperature was raised to 800℃ at a rate of 1000℃ and kept at that temperature for 30min for pre-carbonization treatment; then the temperature was further raised to 800℃ at a rate of 2℃min -1 The temperature was raised to 1500℃ at a rate of 2℃ min-1 and carbonized for 2 hours under protective atmosphere. -1 The temperature was lowered to 800℃ at a rate of 5℃min -1 The temperature was then decreased to 500°C at a rate of 0.5 °C and then naturally cooled to room temperature.

[0069] Example 6

[0070] Example 6 provides a method for preparing a composite electrode slurry containing a high-performance resin-based hard carbon negative electrode material, the specific steps of which are:

[0071] (1) Weigh a certain amount of the hard carbon negative electrode material (active material) of Examples 1, 2, 3, 4, and 5, a certain amount of carbon black (Super-P, conductive agent, Shenzhen Kejing Zhida Technology Co., Ltd., CAS1333-86-4), and a certain amount of binder PVDF, and place the three in a container in sequence to obtain a mixed powder;

[0072] (2) Add a solvent (NMP) to the mixed powder of step (1), the mass of the solvent being 1.5 times the mass of the mixed powder, and ultrasonically disperse the mixture at a power of 100 W for 8 minutes. Then, place a polytetrafluoroethylene magnet in the container and stir at a speed of 400 r / min for 10 hours to uniformly disperse the hard carbon negative electrode material and carbon black (Super-P) to obtain a composite electrode slurry, wherein the mass ratio of the active material, the conductive agent, and the binder is 8:1:1 (specifically 400 mg, 50 mg, and 50 mg, respectively).

[0073] Application Example 1

[0074] The hard carbon negative electrode materials of Examples 1, 2, 3, 4, and 5 were prepared into composite electrode slurries using the method of Example 6, and CR2032 button batteries (sodium ion batteries) were prepared. The specific steps were as follows:

[0075] a) Preparation of electrode sheets: The composite electrode slurry prepared in Example 6 was evenly coated on a copper foil (current collector), dried at 80°C for 10 h, and punched into button-type electrode discs with a diameter of 12 mm.

[0076] b) Button cell assembly: A button cell was assembled using a sodium metal sheet as the counter electrode. The battery model was a CR2032 button cell. The separator type was Whatman GF / D. The main component of the electrolyte used in the battery was sodium salt (sodium hexafluorophosphate); specifically, the electrolyte was 1M NaPF6 in DME.

[0077] Comparative Application Example 1

[0078] The hard carbon composite material of Example 1 was used as the negative electrode material to prepare a composite electrode slurry using the method of Example 6, and a CR2032 button cell (lithium ion battery) was prepared. The specific steps were as follows:

[0079] a) Preparation of electrode sheet: The composite electrode slurry prepared in Example 6 was evenly coated on a copper foil and dried at 80°C for 10 h to form a button-type electrode sheet;

[0080] b) Button cell assembly: A button cell was assembled using a lithium metal sheet as the counter electrode. The battery model was a CR2032 button cell.

[0081] The diameter of the copper foil in step a) is 12 mm.

[0082] In step b), the separator type is PP (polypropylene), and the main component of the electrolyte used in the battery is lithium salt (lithium hexafluorophosphate); preferably, the electrolyte is 1M LiPF6 in EC:DEC=1:1 with 5% FEC.

[0083] Performance Test 1

[0084] The battery performance test of the CR2032 button battery prepared with the hard carbon negative electrode materials of Examples 1, 2, 3, 4, and 5 in Example 1 is carried out. The test results are shown in Table 1 (the test method is shown in Patent Document CN116565147A, a method for preparing a sodium battery hard carbon negative electrode sheet) and Figure 3 At the same time, the battery performance in comparative application example 1 was tested, and the results are shown in Figure 4 .

[0085] The test charge and discharge current is 0.1Ag -1 The charge / discharge cut-off voltage is 0.01 V-2.5 V. The initial capacity and coulombic efficiency of the button cell were tested, and the battery was subjected to a charge / discharge test for 50 cycles.

[0086] Table 1. Test results of charge / discharge performance of Examples 1-5

[0087]

[0088] As can be seen from Table 1, the hard carbon negative electrode material prepared in Example 1 has the highest mass specific capacity and the best capacity retention rate after 50 cycles. In addition, the first coulombic efficiency of Example 4 is relatively high. Figure 3 It can be seen that the sodium ion batteries prepared in Examples 1, 2, 3, 4, and 5 of the present invention have a higher charge capacity.

[0089] Figure 4 The hard carbon negative electrode material of Example 1 is -1 The cycle performance diagram of lithium-ion batteries, from Figure 4 It can be seen that the prepared lithium-ion battery has good charge and discharge efficiency (the closer the charge and discharge efficiency is to 100%, the better) and a high charge specific capacity, indicating that the hard carbon negative electrode material of the present invention has good electrochemical properties.

[0090] The preparation method of the high-performance resin-based hard carbon negative electrode material of the present invention not only simplifies the preparation process of the sodium ion battery negative electrode material in the prior art, but also greatly improves the battery performance. It has good application value and is suitable for industrial promotion and application.

[0091] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-performance resin-based hard carbon negative electrode material, characterized in that: The following steps are involved: 1) Preparation of precursor solution: Mix the phenol monomer and urotropine, add them to solvent I, and stir and dissolve for 10-30 minutes to obtain a clear solution. 2) Preparation of precursor: The solution obtained in step 1) is allowed to stand for 8-36 hours to obtain a reddish-brown liquid, which is dried once to obtain a reddish-brown solid, which is washed and dried a second time to obtain the solid precursor. 3) Preliminary grinding and pulverization: The precursor solid obtained in step 2) is subjected to preliminary grinding and pulverization for 30 to 40 minutes; 4) Precursor carbonization: The ground precursor solid is subjected to high-temperature carbonization treatment to obtain a product, which is a hard carbon anode material; 5) Secondary grinding and crushing: The carbonized hard carbon negative electrode material is subjected to secondary grinding and post-processing to obtain the final product.

2. The preparation method according to claim 1, wherein In step 1), the phenol monomer is one or more of hydroquinone, phloroglucinol, and phenol; in step 1), the solvent I is water, ethanol, or a mixed solvent thereof; the volume ratio of water to ethanol in the mixed solvent is (3-4):

1.

3. The preparation method according to claim 1, wherein In step 1), the ratio of phenol monomer, hexamethylenetetramine and solvent I is (1-6) g:1 g:(25-35) mL.

4. The preparation method according to claim 1, wherein Step 4) Medium-high temperature carbonization treatment is to heat the mixture at 2-5℃ min under protective atmosphere. -1 The temperature was raised to 700-800℃ at a rate of 1-2℃ min, and kept at that temperature for 20-30 min for pre-carbonization treatment; then the temperature was further raised to 700-800℃ at a rate of 1-2℃ min -1 The temperature is raised to 1100℃~1500℃ at a rate of 1~2℃ min, and carbonization treatment is carried out under protective atmosphere for 1~2 hours. -1 The temperature is lowered to 700-800℃ at a rate of 2-5℃ min -1 The temperature was lowered to 400-500°C at a rapid rate, and finally naturally cooled to room temperature.

5. A high-performance resin-based hard carbon negative electrode material is prepared by the method according to any one of claims 1 to 4.

6. A method for preparing a composite electrode slurry comprising the high-performance resin-based hard carbon negative electrode material according to claim 5, characterized in that: The following steps are involved: (1) Weigh a certain amount of active material, conductive agent, and binder, and place them in a container in sequence to obtain a mixed powder; (2) Solvent II is added to the mixed powder of step (1), and ultrasonic dispersion is performed at a power of 80 to 100 W for 8 to 12 minutes, and then stirring is performed at a speed of 300 to 400 r / min for 8 to 12 hours to uniformly disperse the active material and the conductive agent to obtain a composite electrode slurry; the active material in step (1) is the high-performance resin-based hard carbon negative electrode material.

7. The method according to claim 6, wherein In step (1), the conductive agent is carbon black; the binder is PVDF; the solvent II is selected from one of deionized water, ethanol and NMP; and the mass of the solvent II is 1 to 1.5 times the mass of the mixed powder.

8. Use of the high-performance resin-based hard carbon negative electrode material according to claim 5 or the composite electrode slurry prepared according to claim 6 in the preparation of sodium ion batteries.

9. A method for preparing a sodium ion battery using the high-performance resin-based hard carbon negative electrode material according to claim 5 or the composite electrode slurry prepared according to claim 6, comprising the following steps: a) Preparation of electrode sheet: The composite electrode slurry is coated on copper foil and dried at 60-80°C for 8-12 hours to form a button-type electrode sheet; b) Button cell assembly: Use a sodium metal sheet as the counter electrode to assemble a button cell. The battery model is a CR2032 button cell.

10. A sodium ion battery prepared by the method according to claim 9.

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