A hard carbon negative electrode material modified by aqueous binder and a preparation method thereof

Abstract

This invention discloses a water-based binder-modified hard carbon anode material and its preparation method, belonging to the field of battery material technology. The raw materials of the hard carbon anode material include: active material, conductive carbon black, and binder. The active material is bamboo-based hard carbon material, prepared as follows: bamboo is washed, dried, and crushed; it is then soaked in an oxyacid solution for 12 hours, washed, dried, carbonized at 500°C under an inert atmosphere for 5 hours, pulverized, sieved, soaked in hydrochloric acid solution for 12 hours, and calcined at 1400°C under an inert atmosphere for 2 hours to obtain the bamboo-based hard carbon material. The binder is prepared by dissolving sodium alginate in water with sodium polyacrylate, sodium carboxymethyl cellulose, or polydopamine. The preparation method of the hard carbon anode material involves mixing and stirring the raw materials to form a slurry, coating it on copper foil, and drying. The prepared hard carbon anode material exhibits high initial coulombic efficiency and high initial specific capacity.

Description

Technical Field

[0001] This invention relates to the field of battery materials technology, and in particular to a water-based binder-modified hard carbon anode material and its preparation method. Background Technology

[0002] Hard carbon materials, due to their unique amorphous structure, large interlayer spacing, and abundant defect sites, are considered one of the most commercially promising anode materials for sodium-ion batteries. Among the many branches of the hard carbon family, biomass hard carbon is highly favored for its natural advantages of being "green, renewable, and environmentally friendly." Among various biomass precursors, bamboo, with its short growth cycle, high carbon content, high mechanical strength, and unique natural vascular bundle structure, has become an ideal raw material for preparing high-performance carbon materials.

[0003] Based on optimizing the bulk structure of carbon materials, the choice of binder during electrode fabrication also plays a decisive role in the initial coulombic efficiency. Traditional polyvinylidene fluoride (PVDF) binders have the following inherent drawbacks: First, PVDF requires the use of expensive and toxic N-methylpyrrolidone (NMP) solvent for dissolution, which is inconsistent with the development trend of green manufacturing; second, the bond between PVDF and the active material relies solely on weak van der Waals forces, making it difficult to adapt to the volume changes of hard carbon materials during charge and discharge, easily leading to electrode pulverization and interfacial contact failure, thereby increasing irreversible capacity and severely restricting the improvement of initial coulombic efficiency.

[0004] To overcome the aforementioned shortcomings of PVDF systems, environmentally friendly aqueous binder systems have gradually become a research hotspot. Novel aqueous binders such as sodium alginate (SA), sodium polyacrylate (PAAS), and sodium carboxymethyl cellulose (CMC) have shown great potential to replace traditional PVDF due to their good water solubility, abundant functional groups, and stronger interactions with active materials. However, a single aqueous binder often cannot simultaneously meet the multiple requirements of electrode structural stability, interfacial compatibility, and electrochemical performance. How to further improve the overall electrode performance through binder composite optimization strategies remains a pressing technical challenge.

[0005] In summary, developing a bamboo-based hard carbon anode material modified with an aqueous binder, controlling the carbon skeleton structure from the source and optimizing the electrode interface with advanced binder technology, is of great scientific significance and application value for achieving a breakthrough in both high initial coulombic efficiency and high capacity of bamboo-based hard carbon materials. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a water-based binder-modified hard carbon anode material and its preparation method. The binder is prepared by combining sodium alginate (SA) with sodium polyacrylate (PAAS), sodium carboxymethyl cellulose (CMC), or polydopamine (PDA), which effectively improves the coulombic efficiency and capacitance of the anode material prepared from bamboo-based hard carbon.

[0007] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a water-based binder-modified hard carbon anode material, comprising the following raw materials: active material, conductive carbon black, and binder; the binder is prepared by mixing and dissolving sodium alginate with sodium polyacrylate, sodium carboxymethyl cellulose, or polydopamine in water; the active material is bamboo-based hard carbon material.

[0008] Furthermore, the mass ratio of sodium alginate to sodium polyacrylate, sodium carboxymethyl cellulose, or polydopamine is 1:1, and the ratio of solute to solvent in the binder is 1g:40mL.

[0009] Furthermore, the preparation method of the active substance is as follows: bamboo is washed, dried, and crushed, then soaked in an oxyacid solution for 12 hours, washed, dried, and carbonized at 500°C under an argon atmosphere for 5 hours to obtain bamboo charcoal. The charcoal is then ground, sieved, soaked in an HCl solution for 12 hours, washed, dried, and calcined at 1400°C under an argon atmosphere for 2 hours to obtain bamboo-based hard carbon material.

[0010] Furthermore, the oxyacid solution includes one of nitric acid, phosphoric acid, oxalic acid, carbonic acid, silicic acid, boric acid, and permanganic acid solutions, and the concentration of the oxyacid solution is 1M.

[0011] Furthermore, the concentration of the HCl solution is 10 wt%, and the mass ratio of the bamboo charcoal to the HCl solution is 1:10.

[0012] Furthermore, the sieving is performed through a 300-mesh sieve, and the heating rate under an argon atmosphere is 5°C / min.

[0013] The present invention also provides a method for preparing a water-based binder modified hard carbon anode material, comprising the following steps: mixing active material, conductive carbon black and binder in a mass ratio of 8:1:1, stirring into a uniform and non-agglomerated black slurry, uniformly coating it onto copper foil, and drying it at 80°C for 12 hours to obtain the anode material.

[0014] Furthermore, the thickness of the wet film coated on the copper foil is 150 μm.

[0015] Furthermore, the method for preparing the negative electrode material also includes cutting the negative electrode material into circular electrode sheets with a diameter of 12 mm.

[0016] This invention also discloses the application of a water-based binder-modified hard carbon anode material in the preparation of sodium-ion batteries.

[0017] Compared with the prior art, the present invention has at least the following technical advantages and beneficial effects: This invention achieves excellent structural stability and interfacial compatibility in anode materials by controlling the carbon framework structure of bamboo-based hard carbon materials from the source and combining it with an aqueous binder system composited with sodium alginate. The initial coulombic efficiency of bamboo-based hard carbon anode materials prepared using this composite aqueous binder is significantly higher than that prepared with sodium alginate alone. Among them, the SA@PDA anode material exhibits the best performance, achieving an initial coulombic efficiency of 86.57% and a reversible capacity of 345.64 mAh / g.

[0018] The binder described in this invention is prepared by dissolving sodium alginate in water with sodium polyacrylate, sodium carboxymethyl cellulose, or polydopamine. Sodium alginate is rich in carboxyl and hydroxyl functional groups, which can form a strong interfacial bond with the surface of bamboo-based hard carbon through hydrogen bonding and coordination. Sodium polyacrylate, sodium carboxymethyl cellulose, or polydopamine, with their excellent adhesion and self-polymerization properties, construct a three-dimensional network structure inside the electrode. The synergistic effect of the two significantly enhances the interfacial bonding force between the active material, conductive carbon black, and current collector, effectively mitigating the volume expansion and contraction of the hard carbon material during charging and discharging, inhibiting electrode pulverization and interfacial contact failure, thereby reducing irreversible capacity loss caused by structural damage. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 The charge-discharge curve of SA@PAAS negative electrode material in Example 1 as a negative electrode material for sodium-ion batteries is shown. Figure 2 The charge-discharge curve of SA@CMC anode material in Example 2 as a sodium-ion battery anode material is shown. Figure 3 The charge-discharge curve of the SA@PDA negative electrode material in Example 3 as a negative electrode material for a sodium-ion battery is shown. Figure 4 The charge-discharge curves of SA negative electrode material as a negative electrode material in sodium-ion battery are shown in Comparative Example 1. Figure 5Rate performance graphs of sodium-ion batteries prepared using the negative electrode materials of Examples 1-3 and Comparative Example 1; Figure 6 Long-cycle performance graphs of sodium-ion batteries prepared using the negative electrode materials prepared in Examples 1-3 and Comparative Example 1. Detailed Implementation

[0021] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0022] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0023] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0024] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0025] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0026] This invention provides a water-based binder-modified hard carbon anode material, comprising the following raw materials: active material, conductive carbon black, and binder; the binder is prepared by mixing and dissolving sodium alginate with sodium polyacrylate, sodium carboxymethyl cellulose, or polydopamine in water; the active material is bamboo-based hard carbon material.

[0027] In some embodiments of the present invention, the mass ratio of sodium alginate to sodium polyacrylate or sodium carboxymethyl cellulose or polydopamine is 1:1, and the ratio of solute to solvent in the binder is 1g:40mL.

[0028] In some embodiments of the present invention, the preparation method of the active substance is as follows: bamboo is washed, dried and crushed, soaked in an oxyacid solution for 12 hours, washed and dried, heated to 500°C under an argon atmosphere for carbonization, and kept at that temperature for 5 hours to obtain bamboo charcoal, which is then ground, sieved, soaked in an HCl solution for 12 hours, washed and dried, and calcined at 1400°C under an argon atmosphere for 2 hours to obtain bamboo-based hard carbon material.

[0029] In some embodiments of the present invention, the oxyacid solution includes one of nitric acid, phosphoric acid, oxalic acid, carbonic acid, silicic acid, boric acid and permanganic acid solutions, the concentration of the oxyacid solution is 1M, the concentration of the HCl solution is 10wt%, and the mass ratio of bamboo charcoal to HCl solution is 1:10.

[0030] In some embodiments of the present invention, the sieving is performed through a 300-mesh sieve, and the heating rate under an argon atmosphere is 5°C / min.

[0031] This invention also provides a method for preparing a water-based binder-modified hard carbon anode material, comprising the following steps: mixing active material, conductive carbon black and binder in a mass ratio of 8:1:1, stirring to form a uniform and non-agglomerated black slurry, uniformly coating it onto copper foil, and drying it at 80°C for 12 hours to obtain the anode material.

[0032] In some embodiments of the present invention, the thickness of the wet film coated on the copper foil is 150 μm.

[0033] In some embodiments of the present invention, the method for preparing the negative electrode material further includes cutting the negative electrode material into circular electrode sheets with a diameter of 12 mm.

[0034] Example 1 A method for preparing a water-based binder-modified hard carbon anode material includes the following steps: 0.5 g of sodium alginate (SA) and 0.5 g of sodium polyacrylate (PAAS) were added to 40 mL of deionized water and stirred until the white solid was completely dissolved to obtain SA@PAAS adhesive. After washing and drying the bamboo, it was crushed and soaked in a 1 M H2SO4 solution for 12 hours. Then, it was washed with deionized water until neutral and dried in an oven. It was then placed in a tube furnace and heated to 500°C at a rate of 5°C / min under an argon atmosphere for carbonization treatment and held at that temperature for 5 hours. The resulting bamboo charcoal was then ground in a mortar and passed through a 300-mesh sieve. It was then soaked in a 10 wt% HCl solution at a solid-liquid ratio of 1:10 for another 12 hours. After washing with deionized water until neutral and drying, it was finally placed in a high-temperature furnace and heated to 1400°C at a rate of 5°C / min under an argon atmosphere and held at that temperature for 2 hours to obtain the active substance. Subsequently, the active material, conductive carbon black (Super P) and binder were mixed in a mass ratio of 8:1:1 and stirred for 5 hours until a uniform and agglomerated black slurry was formed. Then, the slurry was uniformly coated onto the copper foil using a scraper, and the wet film thickness was controlled to be 150 μm. The coated electrode was then transferred to a vacuum drying oven and dried at 80°C for 12 hours. Finally, the dried electrode sheets were cut into circular electrode sheets with a diameter of 12 mm using a cutting machine to obtain the SA@PAAS negative electrode material.

[0035] The electrochemical performance of this anode material was measured, and the charge-discharge curves for use as a sodium-ion battery anode material are shown below. Figure 1 : Depend on Figure 1 It can be seen that the initial specific capacity of the battery assembled with SA@PAAS anode material can reach 309.85 mAh g. -1 The first coulomb efficiency reached 86.45%.

[0036] Example 2 A method for preparing a water-based binder-modified hard carbon anode material includes the following steps: 0.5 g of sodium alginate (SA) and 0.5 g of sodium carboxymethyl cellulose (CMC) were added to 40 mL of deionized water and stirred until the white solid was completely dissolved to obtain SA@CMC binder; After washing and drying the bamboo, it was crushed and soaked in a 1 M hydrochloric acid solution for 12 hours. Then, it was washed with deionized water until neutral and dried in an oven. The bamboo was then placed in a tube furnace and heated to 500°C at a rate of 5°C / min under an argon atmosphere for carbonization treatment, which was held for 5 hours. The resulting bamboo charcoal was then ground in a mortar and passed through a 300-mesh sieve. It was then soaked in a 10 wt% HCl solution at a solid-liquid ratio of 1:10 for another 12 hours. After washing with deionized water until neutral and drying, it was finally placed in a high-temperature furnace and heated to 1400°C at a rate of 5°C / min under an argon atmosphere for 2 hours to obtain the active substance. Subsequently, the active material, conductive carbon black (Super P) and binder were mixed in a mass ratio of 8:1:1 and stirred for 5 hours until a uniform and agglomerated black slurry was formed. Then, the slurry was uniformly coated onto the copper foil using a scraper, and the wet film thickness was controlled to be 150 μm. The coated electrode was then transferred to a vacuum drying oven and dried at 80°C for 12 hours. Finally, the dried electrode sheets were cut into circular electrode sheets with a diameter of 12 mm using a cutting machine to obtain the SA@CMC anode material.

[0037] The electrochemical performance of this anode material was measured, and the charge-discharge curves for use as a sodium-ion battery anode material are shown below. Figure 2 ,Depend on Figure 2 It can be seen that the initial specific capacity of the battery assembled with SA@CMC anode material can reach 318.37 mAh g. -1 The first coulomb efficiency reached 84.27%.

[0038] Example 3 A method for preparing a water-based binder-modified hard carbon anode material includes the following steps: 0.25 g of dopamine hydrochloride (DA) was weighed and added to 40 ml of deionized water. The solution was stirred with a magnetic stirrer until dissolved to form a dopamine solution. Then, 0.25 g of tris(hydroxymethyl)aminomethane (Tris) was weighed and added to the dopamine solution, and stirring continued until dissolved. During this process, the solution gradually darkened in color, indicating the formation of a polydopamine (PDA) solution. Finally, 0.5 g of sodium alginate (SA) was weighed and added to the polydopamine solution, and stirring continued for 12 hours to obtain a viscous composite adhesive solution, named SA@PDA.

[0039] After washing and drying the bamboo, it was crushed and soaked in a 1 M phosphoric acid solution for 12 hours. Then, it was washed with deionized water until neutral and dried in an oven. The bamboo was then placed in a tube furnace and heated to 500°C at a rate of 5°C / min under an argon atmosphere for carbonization treatment, and held at that temperature for 5 hours. The resulting bamboo charcoal was then ground in a mortar and passed through a 300-mesh sieve. It was then soaked in a 10 wt% HCl solution at a solid-liquid ratio of 1:10 for another 12 hours. After washing with deionized water until neutral and drying, it was finally placed in a high-temperature furnace and heated to 1400°C at a rate of 5°C / min under an argon atmosphere and held at that temperature for 2 hours to obtain the active substance. Subsequently, the active material, conductive carbon black (Super P) and binder were mixed in a mass ratio of 8:1:1 and stirred for 5 hours until a uniform and agglomerated black slurry was formed. Then, the slurry was uniformly coated onto the copper foil using a scraper, and the wet film thickness was controlled to be 150 μm. The coated electrode was then transferred to a vacuum drying oven and dried at 80°C for 12 hours. Finally, the dried electrode sheets are cut into circular electrode sheets with a diameter of 12 mm using a cutting machine to obtain the SA@PDA negative electrode material.

[0040] The electrochemical performance of this anode material was measured, and the charge-discharge curves for use as a sodium-ion battery anode material are shown below. Figure 3 ,Depend on Figure 3 It can be seen that the initial specific capacity of the battery after assembling the SA@PDA anode material can reach 345.64 mAh g. -1 The first coulomb efficiency reached 86.57%.

[0041] Comparative Example 1 A method for preparing a water-based binder-modified hard carbon anode material includes the following steps: Add 1 g of sodium alginate (SA) to 40 ml of deionized water and stir until the white solid is completely dissolved to obtain SA binder; After washing and drying the bamboo, it was crushed and soaked in a 1 M H2SO4 solution for 12 hours. Then, it was washed with deionized water until neutral and dried in an oven. It was then placed in a tube furnace and heated to 500°C at a rate of 5°C / min under an argon atmosphere for carbonization treatment and held at that temperature for 5 hours. The resulting bamboo charcoal was then ground in a mortar and passed through a 300-mesh sieve. It was then soaked in a 10% HCl solution at a solid-liquid ratio of 1:10 for another 12 hours. After washing with deionized water until neutral and drying, it was finally placed in a high-temperature furnace and heated to 1400°C at a rate of 5°C / min under an argon atmosphere and held at that temperature for 2 hours to obtain the active substance. The active material, conductive carbon black (Super P) and binder were then mixed in a mass ratio of 8:1:1, with water as the solvent, and stirred for 5 hours until a uniform black slurry without agglomeration was formed. Subsequently, the slurry was evenly coated onto the copper foil using a scraper, and the wet film thickness was controlled to be 150 μm. The coated electrode was then transferred to a vacuum drying oven and dried at 80°C for 12 hours. Finally, the dried electrode sheets are cut into circular electrode sheets with a diameter of 12 mm using a cutting machine to obtain the SA negative electrode material.

[0042] The electrochemical performance of this anode material was measured, and the charge-discharge curves for use as a sodium-ion battery anode material are shown below. Figure 4 ,Depend on Figure 4 It can be seen that the initial specific capacity of the battery after the SA anode material is assembled is 296.80 mAh g. -1 The initial Coulomb efficiency was 87.23%.

[0043] The rate performance of sodium-ion batteries prepared using the negative electrode materials of Examples 1-3 and Comparative Example 1 is shown in the figure. Figure 5 As shown, by Figure 5 It can be seen that: (1) The rate performance of the SA anode material: the capacity at 0.1C, 0.2C, 0.5C, 1C, 2C and back to 0.1C are 297.5, 278.27, 255.6, 234.55, 202.43 and 279.12 mAh / g, respectively; (2) The rate performance of the SA@PAAS anode material: the capacity at 0.1C, 0.2C, 0.5C, 1C, 2C and back to 0.1C are 296.8, 290.05, 273.76, 251.2, 205.28 and 292.78 mAh / g, respectively. mAh / g; (3) Rate performance of SA@CMC anode material: The capacities at 0.1C, 0.2C, 0.5C, 1C, 2C and back to 0.1C are 310.44, 297.84, 275.73, 248.71, 223.73 and 308.6 mAh / g, respectively; (4) Rate performance of SA@PDA anode material: The capacities at 0.1C, 0.2C, 0.5C, 1C, 2C and back to 0.1C are 325.51, 312.01, 294.38, 273.93, 251.87 and 315.66 mAh / g, respectively. It can be seen that the electrochemical performance of the anode material prepared by a composite aqueous binder of sodium alginate and sodium polyacrylate, sodium carboxymethyl cellulose and polydopamine is significantly higher than that of sodium alginate alone binder.

[0044] The long-cycle performance of sodium-ion batteries prepared with the negative electrode materials of Examples 1-3 and Comparative Example 1 is shown in the figure. Figure 6 As shown, by Figure 6It can be seen that the long-cycle performance is as follows: the initial capacity at 0.1C (1 C=300 mA / g) is as follows: (1) SA anode material is 290.73 mAh / g; (2) SA@PAAS anode material is 305.54 mAh / g; (3) SA@CMC anode material is 314.72 mAh / g; (4) SA@PDA anode material is 345.64 mAh / g. The initial capacity of the anode material prepared by the composite binder is significantly higher than that of the anode material prepared by the single sodium alginate binder.

[0045] After three cycles, the capacities at a current density of 2 C were as follows: (1) SA anode material: 214.07 mAh / g; (2) SA@PAAS anode material: 202.6 mAh / g; (3) SA@CMC anode material: 222.18 mAh / g; (4) SA@PDA anode material: 269.21 mAh / g. The capacities at the 50th cycle were as follows: (1) SA anode material: 189.08 mAh / g; (2) SA@PAAS anode material: 178.6 mAh / g; (3) SA@CMC anode material: 185.99 mAh / g; (4) SA@PDA anode material: 227.4 mAh / g.

[0046] The above performance tests show that the anode material prepared from the binder-modified bamboo-based hard carbon material has high stability.

[0047] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A water-based binder-modified hard carbon anode material, characterized in that, It includes the following raw materials: active material, conductive carbon black and binder; the binder is prepared by mixing and dissolving one of sodium polyacrylate, sodium carboxymethyl cellulose and polydopamine with sodium alginate in water; the active material is bamboo-based hard carbon material.

2. The water-based binder-modified hard carbon anode material according to claim 1, characterized in that, The mass ratio of one of sodium polyacrylate, sodium carboxymethyl cellulose and polydopamine to sodium alginate is 1:1, and the ratio of solute to solvent in the binder is 1g:40mL.

3. The water-based binder-modified hard carbon anode material according to claim 1, characterized in that, The preparation method of the bamboo-based hard carbon material is as follows: bamboo is washed, dried, and crushed, then soaked in an oxyacid solution for 12 hours, washed, dried, and carbonized at 500°C under an argon atmosphere for 5 hours to obtain bamboo charcoal. The charcoal is then ground, sieved, soaked in an HCl solution for 12 hours, washed, dried, and calcined at 1400°C under an argon atmosphere for 2 hours to obtain the bamboo-based hard carbon material.

4. The water-based binder-modified hard carbon anode material according to claim 3, characterized in that, The oxyacid solution includes one of nitric acid, phosphoric acid, oxalic acid, carbonic acid, silicic acid, boric acid, and permanganic acid solutions, and the concentration of the oxyacid solution is 1M.

5. The water-based binder-modified hard carbon anode material according to claim 3, characterized in that, The concentration of the HCl solution is 10 wt%, and the mass ratio of the bamboo charcoal to the HCl solution is 1:

10.

6. The water-based binder-modified hard carbon anode material according to claim 3, characterized in that, The sieving process is a 300-mesh sieve.

7. The water-based binder-modified hard carbon anode material according to claim 3, characterized in that, The heating rate under argon atmosphere is 5°C / min.

8. A method for preparing a water-based binder-modified hard carbon anode material as described in claim 1, characterized in that, The process includes the following steps: mixing active material, conductive carbon black and binder in a mass ratio of 8:1:1, stirring to form a uniform and agglomerated black slurry, uniformly coating it onto copper foil, and drying it at 80°C for 12 hours to obtain the negative electrode material.

9. The method for preparing the water-based binder-modified hard carbon anode material according to claim 8, characterized in that, The thickness of the wet film coated on the copper foil is 150 μm.

10. The application of a water-based binder-modified hard carbon anode material as described in claims 1-6 in the preparation of sodium-ion batteries.

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