A sodium-ion battery pitch-based anode material and its preparation method

Abstract

This invention discloses a sodium-ion battery asphalt-based anode material and its preparation method, relating to the field of electrode material preparation technology. The sodium-ion battery asphalt-based anode material is composed of a porous hard carbon-based ternary composite material and a modified asphalt material. The porous hard carbon-based ternary composite material and the modified asphalt material are combined, with the porous hard carbon-based ternary composite material as the active core and the modified asphalt material forming a derived carbon shell. The pore structure between the active core and the carbon shell is tightly and stably filled, forming an asphalt-based anode material with rich multi-level pore structure characteristics. This significantly improves the sodium storage capacity, rate performance, and cycle stability of the asphalt material, thus optimizing battery performance.

Description

Technical Field

[0001] This invention belongs to the field of electrode material preparation technology, specifically referring to a sodium-ion battery pitch-based negative electrode material and its preparation method. Background Technology

[0002] With the development of energy storage technology, lithium-ion batteries have been widely used. However, the scarcity and uneven distribution of lithium resources in the Earth's crust hinders their application in large-scale energy storage systems. Compared to lithium resources, sodium resources are widely distributed and have similar physical and chemical properties to lithium. Therefore, sodium-ion batteries are considered an effective alternative to lithium-ion batteries. However, due to kinetic limitations, sodium ions cannot be embedded in graphite layers, making graphite anodes, which are widely used in lithium-ion batteries, unsuitable for sodium-ion batteries. Therefore, finding suitable anode materials is currently the key to the commercialization of sodium-ion batteries.

[0003] Among numerous sodium-ion battery anode materials, hard carbon is considered the most commercially promising material due to its unique disordered structure and large interlayer spacing, which result in high reversible sodium storage capacity and cycle stability. Hard carbon precursors are widely available, mainly including biomass, resins, coal, and bitumen. Biomass, as a green resource, has been extensively studied, but its high dependence on seasons and geographical locations, as well as its low carbon yield, limit its development as a hard carbon precursor. Phenolic resins have a high carbon yield, but their toxicity and cost hinder their large-scale application in sodium-ion batteries. Bitumen, as a byproduct of the coal and petroleum industries, has abundant reserves, an economical price, and a high carbon yield, making it the most promising hard carbon precursor.

[0004] The existing technology currently has the following main problems:

[0005] Graphitization easily occurs during the high-temperature carbonization of asphalt, resulting in excessively small interlayer spacing, which is not conducive to the insertion and extraction of sodium ions. This leads to low sodium storage capacity and poor rate performance, greatly reducing battery performance. Summary of the Invention

[0006] In view of the above situation and to overcome the defects of the prior art, the present invention proposes a sodium-ion battery asphalt-based negative electrode material, comprising the following components in parts by weight: 50-60 parts of porous hard carbon-based ternary composite material and 40-50 parts of modified asphalt material.

[0007] The porous hard carbon-based ternary composite material comprises the following components in parts by weight: 10-15 parts of molybdenum disulfide precursor powder, 60-70 parts of boron-doped porous hard carbon material, 8-10 parts of iron nitrate nonahydrate, 3-5 parts of cobalt nitrate hexahydrate, 8-10 parts of sodium thiosulfate, and 8-10 parts of glucose.

[0008] The modified asphalt material comprises the following components in parts by weight: 10-20 parts asphalt, 10-30 parts diethoxymethane, 30-80 parts aluminum chloride, 10-20 parts thiourea, and 10-20 parts zinc chloride.

[0009] The preparation method of the porous hard carbon-based ternary composite material specifically includes the following steps:

[0010] (1) Hydroxyethyl ethylenediamine triacetic acid and 2.0-2.5g ammonium molybdate are dissolved in 20mL of deionized water. During magnetic stirring, 28% ammonia water is added to adjust the pH to 7.0-8.0. Then, 9.5-11.5g ammonium sulfide is added and stirred evenly. Then, it is transferred to a high-pressure reactor and heated at 180-200℃ for 6-12h. After centrifugation, the precipitate is washed with deionized water and ethanol solution 3-5 times in sequence. Finally, it is vacuum dried at 60-80℃. In this process, the long-chain molecular structure of hydroxyethyl ethylenediamine triacetic acid can be adsorbed on specific crystal planes of molybdenum disulfide crystals, inhibiting vertical stacking and promoting lateral growth, thus forming ultrathin nanosheets with a three-layer sandwich structure of S-Mo-S. This ultrathin layered structure and sulfur vacancies provide more sodium ion insertion sites and adsorption sites, which improves the sodium storage capacity. At the same time, the diffusion path of fewer layers can accelerate the transport of sodium ions and enhance the rate performance, thus obtaining molybdenum disulfide precursor powder.

[0011] (2) 1.0-2.0 g of perylene-3,4,9,10-tetracarboxylic dianhydride and 1.0-2.0 g of phenolic resin were ultrasonically dispersed uniformly in 15 mL of ethanol solution. Boric acid was added, and the uniformly mixed solution was dried in an oven at 80 °C for 16-20 h. The resulting red powder was placed in a tube furnace and pyrolyzed at 900-1100 °C for 0.5-1 h under an argon atmosphere. After cooling to room temperature, the perylene-3,4,9,10-tetracarboxylic dianhydride underwent high-temperature pyrolysis, and its aromatic ring structure was... During carbonization, carbon monoxide and carbon dioxide are released, forming uniform micropores. The pyrolysis of phenolic resin contributes to the mesopores, thus forming a pore structure that stores sodium in micropores and transfers mass in mesopores, resulting in high capacity and excellent rate performance. Boric acid decomposes into B2O3 at high temperature, and some B atoms replace C in the carbon skeleton to form BC bonds. Boron doping can not only expand the carbon interlayer spacing, which is beneficial to the insertion and extraction of sodium ions, but also enhance the stability of the carbon skeleton and suppress the volume expansion during cycling, thus obtaining boron-doped porous hard carbon materials.

[0012] (3) Ferric nitrate nonahydrate, cobalt nitrate hexahydrate, sodium thiosulfate, the molybdenum disulfide precursor powder described in step (1), and the boron-doped porous hard carbon material described in step (2) are ground and mixed. After thorough grinding and uniform mixing, glucose is added. The mixture is first purified at 280-300℃ for 0.5-1h under an argon flow, then sulfided at 500-600℃ for 1-2h. After cooling to room temperature, the powder is evenly spread on the sample stage and subjected to argon plasma treatment for 10-15min at a power of 60-80W and a pressure of 10-30Pa. Through the pyrolysis composite process, a core structure is formed with boron-doped porous hard carbon material as the skeleton, loaded with FeS, Co9S8 and MoS2 nanoparticles, and coated with a conductive carbon layer. The three-dimensional conductive network constructed from hard carbon materials provides a fast electron transport channel. Its pore structure effectively buffers the volumetric strain of sodium ion insertion and extraction. FeS, Co9S8, and MoS2 serve as active phases, synergistically enhancing sodium storage capacity. The carbon coating layer reduces direct contact between the active material and the electrolyte, inhibits the volume expansion of nanoparticles, and improves cycle stability. Plasma treatment directionally introduces sulfur vacancies into MoS2. The uncoordinated Mo atoms around the sulfur vacancies become new adsorption sites for sodium ions, which is beneficial to improving capacity. Sulfur vacancies introduce intermediate energy levels into the band gap of MoS2, narrowing the band gap, promoting electron transition and enhancing conductivity. It can also graphitize part of the carbon layer, reducing charge transfer impedance and improving rate performance, resulting in a porous hard carbon-based ternary composite material.

[0013] Preferably, in step (1), the amount of hydroxyethyl ethylenediamine triacetic acid added is 3.8-4.2g. Hydroxyethyl ethylenediamine triacetic acid partially decomposes under high temperature hydrothermal conditions, and its residual oxygen- and nitrogen-containing groups will compete with sulfur in molybdenum disulfide for coordination, induce the formation of sulfur vacancies, and improve the electrochemical activity and electronic conductivity of the material.

[0014] Preferably, in step (2), the amount of boric acid added is 0.1-0.5g. As a crosslinking agent, boric acid can enhance the thermal stability of phenolic resin, promote the formation of more closed-cell structures, and improve the first-cycle coulombic efficiency.

[0015] Preferably, in step (3), the amount of glucose added is 0.8-1.0g. The pyrolysis of glucose can form an amorphous carbon shell coating layer, which inhibits the volume expansion of FeS / Co9S8 during charging and discharging, reduces the dissolution of polysulfides in the electrolyte, and improves cycle stability.

[0016] This invention also provides a method for preparing a sodium-ion battery pitch-based anode material, specifically including the following steps:

[0017] S1. Dissolve 1.0-2.0g of asphalt powder with a softening point of 80-100℃ in 75mL of o-dichlorobenzene solvent, add 1.0-3.0g of diethoxymethane and 3.0-8.0g of aluminum chloride, then add thiourea and zinc chloride. Reflux the mixture at 100-120℃ for 6-8 hours, centrifuge, collect the precipitate in a Soxhlet extractor, wash with methanol for 8-12 hours, boil in 3.6% hydrochloric acid solution for 1-2 hours, dry, wash with 1,2-dichloroethane solvent for 2-3 hours, dry in a vacuum oven at 80℃ for 12 hours, then transfer to a tube furnace and heat to 200-300℃. The mixture is kept at 00℃ for 0.5-1h, then heated to 500-800℃ for 0.5-1h, and finally heated to 800-1000℃ for 1-2h for carbonization. Under the catalysis of aluminum chloride, diethoxymethane condenses with asphalt to form a three-dimensional cross-linked network, which reduces the risk of structural collapse in the graphitized region of the asphalt and improves its stability. Further N / S doping and pore-forming treatment of the cross-linked network improves the graphitic microcrystalline structure of the asphalt, widens the interlayer spacing, enriches the active sites, facilitates the insertion and extraction of sodium ions, alleviates volume strain, and effectively enhances the specific capacity, rate performance and cycle stability of the material, thus obtaining modified asphalt material.

[0018] S2. Disperse the porous hard carbon-based ternary composite material in 200 mL of N-methylpyrrolidone solvent and sonicate for 20-30 min to form a porous hard carbon-based ternary composite material dispersion. Set aside. Add the modified asphalt material from step S1 to 100 mL of N-methylpyrrolidone solvent and heat to 60-80℃ to promote dissolution, forming a modified asphalt material solution. Set aside. Then mix the porous hard carbon-based ternary composite material dispersion and the modified asphalt material solution, magnetically stir for 2-4 h, sonicate for 0.5-1 h, and dry at 60℃ to evaporate the solvent. The resulting solid mixture is carbonized at 600-800℃ for 1-3 h under an argon flow. This process combines the porous hard carbon-based ternary composite material with the modified asphalt material. The combination of these elements forms a core-shell-pore three-level structure anode material. The porous hard carbon-based ternary composite material serves as the active core, while the modified asphalt material generates a derived carbon shell. The pore structure between the active core and the carbon shell is tightly and stably filled, exhibiting abundant hierarchical channels. The active core and pore structure provide sufficient sodium ion adsorption sites, the three-dimensional conductive network and hierarchical channels optimize the rate performance, the core-shell structure provides a buffer space for sodium ion insertion, and the outer cross-linked asphalt network inhibits carbon layer peeling, thereby effectively alleviating volume expansion and enhancing structural stability. This significantly improves the sodium storage capacity, rate performance and cycle stability of the asphalt material, optimizes battery performance, and yields a sodium-ion battery asphalt-based anode material.

[0019] Preferably, in step S1, the amount of thiourea and zinc chloride added is 1.0-2.0 g each. The amino group of thiourea condenses with the aromatic ring of pitch to form an N / S co-doped structure, which stabilizes the carbon skeleton and increases the active sites, thereby improving the specific capacity and cycle stability. Zinc chloride acts as a template agent and pore-forming agent, forming microporous and mesoporous structures, optimizing the transport path, and is beneficial to enhancing rate performance.

[0020] The beneficial effects achieved by this invention are as follows:

[0021] This invention combines a porous hard carbon-based ternary composite material with modified asphalt material. The porous hard carbon-based ternary composite material serves as the active core, while the modified asphalt material forms a derived carbon shell. The pore structure between the active core and the carbon shell is tightly and stably filled, forming an asphalt-based anode material with a rich hierarchical pore structure. This significantly improves the sodium storage capacity, rate performance, and cycle stability of the asphalt material, optimizing battery performance. In the porous hard carbon-based ternary composite material, boron-doped porous hard carbon material forms the framework, loading FeS, Co9S8, and MoS2 nanoparticles and coating them with a conductive carbon layer formed by glucose pyrolysis. The three-dimensional conductive network constructed by the boron-doped porous hard carbon material provides a fast electron transport channel, and its hierarchical pores effectively buffer the volume expansion during sodium ion insertion and extraction. FeS, Co9S8, and MoS2 act as the active phase, synergistically enhancing the sodium storage capacity. The carbon coating layer reduces direct contact between the active material and the electrolyte, inhibits the volume expansion and aggregation of nanoparticles, and optimizes the overall performance. The ion diffusion pathway improves cycle stability. Plasma treatment directionally introduces sulfur vacancies into MoS2, increasing sodium ion adsorption sites and improving capacity. Sulfur vacancies introduce intermediate energy levels into the MoS2 band gap, narrowing the band gap, promoting electronic transitions and enhancing conductivity. It can also graphitize some carbon layers, reducing charge transfer impedance and improving rate performance. In the modified asphalt material, diethoxymethane condenses with asphalt to form a three-dimensional cross-linked network, reducing the risk of structural collapse in the graphitized asphalt region and improving structural stability. Furthermore, N / S doping sites and pore-forming treatment are introduced into the cross-linked network, widening the interlayer spacing, enriching active sites, which is beneficial for sodium ion insertion and extraction, and can also alleviate volume strain, thereby enhancing the specific capacity, rate performance, and cycle stability of the material. This invention uses porous hard carbon-based ternary composite materials and modified asphalt materials to prepare a sodium-ion battery asphalt-based anode material, improving the sodium storage capacity, rate performance, and cycle stability of the asphalt material, and optimizing battery performance and lifespan. Attached Figure Description

[0022] Figure 1 This is a scanning electron microscope image of the sodium-ion battery pitch-based negative electrode material prepared in Example 1 of the present invention;

[0023] Figure 2The specific capacity results are shown in the figures for Examples 1-4 and Comparative Examples 1-3 of the present invention.

[0024] Figure 3 The graph shows the discharge specific capacity retention results of Examples 1-4 and Comparative Examples 1-3 of the present invention;

[0025] Figure 4 The graph shows the capacity retention results after 1000 cycles for Examples 1-4 and Comparative Examples 1-3 of the present invention. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0028] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; unless otherwise specified, the experimental materials used in the following embodiments are all purchased from commercial channels.

[0029] Example 1

[0030] This embodiment proposes a sodium-ion battery asphalt-based anode material, comprising the following components by weight: 60 parts of porous hard carbon-based ternary composite material and 40 parts of modified asphalt material.

[0031] The porous hard carbon-based ternary composite material comprises the following components in parts by weight: 15 parts of molybdenum disulfide precursor powder, 70 parts of boron-doped porous hard carbon material, 10 parts of iron nitrate nonahydrate, 5 parts of cobalt nitrate hexahydrate, 10 parts of sodium thiosulfate, and 8-10 parts of glucose.

[0032] Modified asphalt material, comprising the following components in parts by weight: 20 parts asphalt, 30 parts diethoxymethane, 80 parts aluminum chloride, 20 parts thiourea, and 20 parts zinc chloride.

[0033] The preparation method of porous hard carbon-based ternary composite materials specifically includes the following steps:

[0034] (1) Dissolve hydroxyethyl ethylenediamine triacetic acid (HEDTA) and 2.5 g ammonium molybdate in 20 mL of deionized water. The amount of HEDTA added is 4.2 g. HEDTA partially decomposes under high temperature hydrothermal conditions. Its residual oxygen- and nitrogen-containing groups will compete with sulfur in molybdenum disulfide for coordination, inducing the formation of sulfur vacancies and improving the electrochemical activity and electronic conductivity of the material. During magnetic stirring, 28% ammonia water is added to adjust the pH to 8.0. Then, 11.5 g ammonium sulfide is added and stirred evenly. Then, it is transferred to a high-pressure reactor and heated at 200 °C. After heating for 12 hours and centrifuging, the precipitate was washed five times with deionized water and ethanol solution, and finally dried under vacuum at 80°C. In this process, the long-chain molecular structure of hydroxyethyl ethylenediamine triacetic acid can be adsorbed on specific crystal planes of molybdenum disulfide crystals, inhibiting vertical stacking and promoting lateral growth, thereby forming ultrathin nanosheets with an S-Mo-S three-layer sandwich structure. This ultrathin layered structure and sulfur vacancies provide more sodium ion insertion sites and adsorption sites, improving sodium storage capacity. At the same time, the few-layer diffusion path can accelerate the transport of sodium ions and enhance rate performance, resulting in molybdenum disulfide precursor powder.

[0035] (2) 2.0 g of perylene-3,4,9,10-tetracarboxylic dianhydride and 2.0 g of phenolic resin were ultrasonically dispersed uniformly in 15 mL of ethanol solution. Boric acid was added at a rate of 0.5 g. Boric acid, as a crosslinking agent, can enhance the thermal stability of phenolic resin, promote the formation of more closed-cell structures, and improve the first-cycle coulombic efficiency. The uniformly mixed solution was then dried in an oven at 80 °C for 20 h. The resulting red powder was placed in a tube furnace and pyrolyzed at 1100 °C for 1 h under an argon atmosphere. After cooling to room temperature, perylene-3,4,9,10- The high-temperature pyrolysis of tetracarboxylic acid dianhydride releases carbon monoxide and carbon dioxide during carbonization, forming uniform micropores. The pyrolysis of phenolic resin contributes to the mesopores, thus forming a pore structure that stores sodium in micropores and transfers mass in mesopores, exhibiting high capacity and excellent rate performance. Meanwhile, boric acid decomposes into B2O3 at high temperature, with some B atoms replacing C in the carbon skeleton to form BC bonds. Boron doping not only expands the carbon interlayer spacing, which is beneficial for the insertion and extraction of sodium ions, but also enhances the stability of the carbon skeleton and suppresses volume expansion during cycling, resulting in boron-doped porous hard carbon materials.

[0036] (3) Ferric nitrate nonahydrate, cobalt nitrate hexahydrate, sodium thiosulfate, the molybdenum disulfide precursor powder mentioned in step (1), and the boron-doped porous hard carbon material mentioned in step (2) are ground and mixed. After being ground evenly, glucose is added. The amount of glucose added is 1.0g. The pyrolysis of glucose can form an amorphous carbon shell coating layer, which inhibits the volume expansion of FeS / Co9S8 during charging and discharging, reduces the dissolution of polysulfides in the electrolyte, and improves cycle stability. Under an argon flow, the powder is first removed at 300℃ for 1h, then sulfided at 600℃ for 2h, cooled to room temperature, and finally the powder is evenly spread on the sample stage. It is then treated with argon plasma for 15min at a power of 80W and a pressure of 30Pa. Through the pyrolysis composite process, a structure is formed with boron-doped porous hard carbon material as the skeleton and FeS, Co9S8 and M The core structure consists of oS2 nanoparticles coated with a conductive carbon layer. The three-dimensional conductive network constructed from boron-doped porous hard carbon material provides a fast electron transport channel. Its pore structure effectively buffers the volume strain of sodium ion insertion and extraction. FeS, Co9S8, and MoS2 serve as active phases, synergistically enhancing sodium storage capacity. The carbon coating reduces direct contact between the active material and the electrolyte, inhibits the volume expansion of nanoparticles, and improves cycle stability. Plasma treatment directionally introduces sulfur vacancies into MoS2. The uncoordinated Mo atoms around the sulfur vacancies become new adsorption sites for sodium ions, which is beneficial to improving capacity. Sulfur vacancies introduce intermediate energy levels into the band gap of MoS2, narrowing the band gap, promoting electron transitions and enhancing conductivity. It can also graphitize part of the carbon layer, reducing charge transfer impedance and improving rate performance, resulting in a porous hard carbon-based ternary composite material.

[0037] This embodiment provides a method for preparing a sodium-ion battery pitch-based anode material, specifically including the following steps:

[0038] S1. Dissolve 2.0 g of asphalt powder with a softening point of 100 °C in 75 mL of o-dichlorobenzene solvent. Add 3.0 g of diethoxymethane and 8.0 g of aluminum chloride, then add 2.0 g each of thiourea and zinc chloride. The amino groups of thiourea condense with the aromatic rings of the asphalt to form an N / S co-doped structure, which stabilizes the carbon skeleton and increases the active sites, thereby improving the specific capacity and cycling stability. Zinc chloride acts as a template and pore-forming agent, forming microporous and mesoporous structures, optimizing the transport path, and enhancing rate performance. Then, reflux the reaction at 120 °C for 8 h, centrifuge, collect the precipitate and place it in a Soxhlet extractor. Wash with methanol for 12 h and place in a 3.6% hydrochloric acid solution. After boiling for 2 hours and drying, the material was washed with 1,2-dichloroethane solvent for 3 hours and dried in a vacuum oven at 80°C for 12 hours. Then, it was transferred to a tube furnace, heated to 300°C for 1 hour, then heated to 800°C for 1 hour, and finally heated to 1000°C for 2 hours for carbonization. Under the catalysis of aluminum chloride, diethoxymethane condensed with asphalt to form a three-dimensional cross-linked network, which reduced the risk of structural collapse in the graphitized region of the asphalt and improved its stability. Further N / S doping and pore-forming treatment of the cross-linked network improved the graphitic microcrystalline structure of the asphalt, widened the interlayer spacing, enriched the active sites, facilitated the insertion and extraction of sodium ions, and alleviated volume strain. This effectively enhanced the specific capacity, rate performance and cycle stability of the material, resulting in modified asphalt material.

[0039] S2. Disperse the porous hard carbon-based ternary composite material in 200 mL of N-methylpyrrolidone solvent and sonicate for 30 min to form a porous hard carbon-based ternary composite material dispersion. Set aside. Add the modified asphalt material from step S1 to 100 mL of N-methylpyrrolidone solvent and heat to 80 °C to promote dissolution, forming a modified asphalt material solution. Set aside. Then mix the porous hard carbon-based ternary composite material dispersion and the modified asphalt material solution, magnetically stir for 4 h, sonicate for 1 h, and dry at 60 °C to evaporate the solvent. The resulting solid mixture is carbonized at 800 °C for 3 h under an argon flow. Through the combination of the porous hard carbon-based ternary composite material and the modified asphalt material, a core- A three-level shell-pore anode material is developed, with a porous hard carbon-based ternary composite material as the active core and modified bitumen material generating a derived carbon shell. The pore structure between the active core and the carbon shell is tightly and stably filled, exhibiting abundant hierarchical channels. The active core and pore structure provide sufficient sodium ion adsorption sites, while the three-dimensional conductive network and hierarchical channels optimize rate performance. The core-shell structure provides a buffer space for sodium ion insertion, and the outer cross-linked bitumen network inhibits carbon layer stripping, thereby effectively mitigating volume expansion and enhancing structural stability. This significantly improves the sodium storage capacity, rate performance, and cycle stability of the bitumen material, optimizing battery performance and yielding a bitumen-based anode material for sodium-ion batteries.

[0040] In this embodiment, the prepared sodium-ion battery pitch-based anode material was subjected to scanning electron microscopy to observe its microstructure. Figure 1 The image shows a 10,000x magnified SEM image of the sodium-ion battery pitch-based anode material prepared in Example 1. As shown in the figure, the sodium-ion battery pitch-based anode material prepared in this example exhibits a filled multi-level pore structure.

[0041] Example 2

[0042] This embodiment proposes a sodium-ion battery asphalt-based anode material, comprising the following components by weight: 50 parts of porous hard carbon-based ternary composite material and 50 parts of modified asphalt material.

[0043] The porous hard carbon-based ternary composite material comprises the following components in parts by weight: 10 parts of molybdenum disulfide precursor powder, 60 parts of boron-doped porous hard carbon material, 8 parts of iron nitrate nonahydrate, 3 parts of cobalt nitrate hexahydrate, 8 parts of sodium thiosulfate, and 8 parts of glucose.

[0044] Modified bitumen material, comprising the following components in parts by weight: 10 parts bitumen, 10 parts diethoxymethane, 30 parts aluminum chloride, 10 parts thiourea, and 10 parts zinc chloride.

[0045] The preparation method of porous hard carbon-based ternary composite materials specifically includes the following steps:

[0046] (1) Dissolve hydroxyethyl ethylenediamine triacetic acid (HEDTA) and 2.0 g ammonium molybdate in 20 mL of deionized water. The amount of HEDTA added is 3.8 g. HEDTA partially decomposes under high temperature hydrothermal conditions. Its residual oxygen- and nitrogen-containing groups will compete with sulfur in molybdenum disulfide for coordination, inducing the formation of sulfur vacancies and improving the electrochemical activity and electronic conductivity of the material. During magnetic stirring, 28% ammonia water is added to adjust the pH to 7.0. Then, 9.5 g ammonium sulfide is added and stirred evenly. Then, it is transferred to a high-pressure reactor and heated at 180°C. After heating for 6 hours and centrifuging, the precipitate was washed three times with deionized water and ethanol solution, and finally dried under vacuum at 60°C. In this process, the long-chain molecular structure of hydroxyethyl ethylenediamine triacetic acid can be adsorbed on specific crystal planes of molybdenum disulfide crystals, inhibiting vertical stacking and promoting lateral growth, thereby forming ultrathin nanosheets with an S-Mo-S three-layer sandwich structure. This ultrathin layered structure and sulfur vacancies provide more sodium ion insertion sites and adsorption sites, improving sodium storage capacity. At the same time, the few-layer diffusion path can accelerate the transport of sodium ions and enhance rate performance, resulting in molybdenum disulfide precursor powder.

[0047] (2) 1.0 g of perylene-3,4,9,10-tetracarboxylic dianhydride and 1.0 g of phenolic resin were ultrasonically dispersed uniformly in 15 mL of ethanol solution. Boric acid was added at a rate of 0.1 g. Boric acid, as a crosslinking agent, can enhance the thermal stability of phenolic resin, promote the formation of more closed-cell structures, and improve the first-cycle coulombic efficiency. The uniformly mixed solution was then dried in an oven at 80 °C for 16 h. The resulting red powder was placed in a tube furnace and pyrolyzed at 900 °C for 0.5 h under an argon atmosphere. After cooling to room temperature, perylene-3,4,9,10- The high-temperature pyrolysis of tetracarboxylic acid dianhydride releases carbon monoxide and carbon dioxide during carbonization, forming uniform micropores. The pyrolysis of phenolic resin contributes to the mesopores, thus forming a pore structure that stores sodium in micropores and transfers mass in mesopores, exhibiting high capacity and excellent rate performance. Meanwhile, boric acid decomposes into B2O3 at high temperature, with some B atoms replacing C in the carbon skeleton to form BC bonds. Boron doping not only expands the carbon interlayer spacing, which is beneficial for the insertion and extraction of sodium ions, but also enhances the stability of the carbon skeleton and suppresses volume expansion during cycling, resulting in boron-doped porous hard carbon materials.

[0048] (3) Ferric nitrate nonahydrate, cobalt nitrate hexahydrate, sodium thiosulfate, the molybdenum disulfide precursor powder mentioned in step (1), and the boron-doped porous hard carbon material mentioned in step (2) are ground and mixed. After thorough grinding and uniform mixing, glucose is added. The amount of glucose added is 0.8g. The pyrolysis of glucose can form an amorphous carbon shell coating layer, which inhibits the volume expansion of FeS / Co9S8 during charging and discharging, reduces the dissolution of polysulfides in the electrolyte, and improves cycle stability. Under an argon flow, the powder is first removed at 280℃ for 0.5h, then sulfided at 500℃ for 1h, cooled to room temperature, and finally the powder is evenly spread on the sample stage. It is then subjected to argon plasma treatment for 10min at a power of 60W and a pressure of 10Pa. Through the pyrolysis composite process, a structure is formed with boron-doped porous hard carbon material as the skeleton and FeS, Co9S8 and... The core structure of MoS2 nanoparticles coated with a conductive carbon layer, along with the three-dimensional conductive network constructed from boron-doped porous hard carbon material, provides a fast electron transport channel. Its pore structure effectively buffers the volume strain of sodium ion insertion and extraction. FeS, Co9S8, and MoS2 serve as active phases, synergistically enhancing sodium storage capacity. The carbon coating reduces direct contact between the active material and the electrolyte, inhibits the volume expansion of the nanoparticles, and improves cycle stability. Plasma treatment directionally introduces sulfur vacancies into MoS2, and the uncoordinated Mo atoms around the sulfur vacancies become new adsorption sites for sodium ions, which is beneficial to improving capacity. Sulfur vacancies introduce intermediate energy levels into the band gap of MoS2, narrowing the band gap, promoting electron transitions and enhancing conductivity. It can also graphitize part of the carbon layer, reducing charge transfer impedance and improving rate performance, resulting in a porous hard carbon-based ternary composite material.

[0049] This embodiment provides a method for preparing a sodium-ion battery pitch-based anode material, specifically including the following steps:

[0050] S1. Dissolve 1.0 g of asphalt powder with a softening point of 80 °C in 75 mL of o-dichlorobenzene solvent, add 1.0 g of diethoxymethane and 3.0 g of aluminum chloride, then add thiourea and zinc chloride, each added in 1.0 g amounts. The amino groups of thiourea condense with the aromatic rings of the asphalt to form an N / S co-doped structure, which stabilizes the carbon skeleton and increases active sites, thereby improving specific capacity and cycling stability. Zinc chloride acts as a template and pore-forming agent, forming microporous and mesoporous structures, optimizing transport paths, and enhancing rate performance. Then, reflux the reaction at 100 °C for 6 h, centrifuge, collect the precipitate and place it in a Soxhlet extractor, wash with methanol for 8 h, and boil in a 3.6% hydrochloric acid solution. After drying for 1 hour, the material was washed with 1,2-dichloroethane solvent for 2 hours, dried in a vacuum oven at 80°C for 12 hours, and then transferred to a tube furnace. The furnace was first heated to 200°C and held at that temperature for 0.5 hours, then heated to 500°C and held at that temperature for 0.5 hours, and finally heated to 800°C for 1 hour of carbonization treatment. Under the catalysis of aluminum chloride, diethoxymethane condensed with asphalt to form a three-dimensional cross-linked network, which reduced the risk of structural collapse in the graphitized region of the asphalt and improved its stability. Further N / S doping and pore-forming treatment of the cross-linked network improved the graphitic microcrystalline structure of the asphalt, widened the interlayer spacing, enriched the active sites, facilitated the insertion and extraction of sodium ions, and also alleviated volume strain. This effectively enhanced the specific capacity, rate performance and cycle stability of the material, resulting in modified asphalt material.

[0051] S2. Disperse the porous hard carbon-based ternary composite material in 200 mL of N-methylpyrrolidone solvent and sonicate for 20 min to form a porous hard carbon-based ternary composite material dispersion, set aside. Add the modified asphalt material from step S1 to 100 mL of N-methylpyrrolidone solvent and heat to 60 °C to promote dissolution, forming a modified asphalt material solution, set aside. Then mix the porous hard carbon-based ternary composite material dispersion and the modified asphalt material solution, magnetically stir for 2 h, sonicate for 0.5 h, and dry at 60 °C to evaporate the solvent. The resulting solid mixture is carbonized at 600 °C for 1 h under an argon flow. Through the combination of the porous hard carbon-based ternary composite material and the modified asphalt material, a core is formed. The anode material features a three-tiered shell-pore structure. A porous hard carbon-based ternary composite material serves as the active core, while modified bitumen material generates a derived carbon shell. The pore structure between the active core and the carbon shell is tightly and stably filled, exhibiting abundant hierarchical channels. The active core and pore structure provide ample sodium ion adsorption sites. The three-dimensional conductive network and hierarchical channels optimize rate performance. The core-shell structure provides a buffer space for sodium ion insertion, and the outer cross-linked bitumen network inhibits carbon layer stripping, effectively mitigating volume expansion and enhancing structural stability. This significantly improves the sodium storage capacity, rate performance, and cycle stability of the bitumen material, optimizing battery performance and yielding a bitumen-based anode material for sodium-ion batteries.

[0052] Example 3

[0053] This embodiment proposes a sodium-ion battery asphalt-based anode material, comprising the following components by weight: 55 parts of porous hard carbon-based ternary composite material and 45 parts of modified asphalt material.

[0054] The porous hard carbon-based ternary composite material comprises the following components in parts by weight: 12.5 parts of molybdenum disulfide precursor powder, 65 parts of boron-doped porous hard carbon material, 9 parts of iron nitrate nonahydrate, 4 parts of cobalt nitrate hexahydrate, 9 parts of sodium thiosulfate, and 9 parts of glucose.

[0055] Modified asphalt material, comprising the following components in parts by weight: 15 parts asphalt, 20 parts diethoxymethane, 55 parts aluminum chloride, 15 parts thiourea, and 15 parts zinc chloride.

[0056] The preparation method of porous hard carbon-based ternary composite materials specifically includes the following steps:

[0057] (1) Dissolve hydroxyethyl ethylenediamine triacetic acid (HEDTA) and 2.25 g ammonium molybdate in 20 mL of deionized water. The amount of HEDTA added is 4.0 g. HEDTA partially decomposes under high temperature hydrothermal conditions. Its residual oxygen- and nitrogen-containing groups will compete with sulfur in molybdenum disulfide for coordination, inducing the formation of sulfur vacancies and improving the electrochemical activity and electronic conductivity of the material. During magnetic stirring, 28% ammonia water is added to adjust the pH to 7.5. Then, 10.5 g ammonium sulfide is added and stirred evenly. Then, it is transferred to a high-pressure reactor and heated at 190 °C. After heating for 9 hours and centrifugation, the precipitate was washed four times with deionized water and ethanol solution, and finally dried under vacuum at 70°C. In this process, the long-chain molecular structure of hydroxyethyl ethylenediamine triacetic acid can be adsorbed on specific crystal faces of molybdenum disulfide crystals, inhibiting vertical stacking and promoting lateral growth, thereby forming ultrathin nanosheets with an S-Mo-S three-layer sandwich structure. This ultrathin layered structure and sulfur vacancies provide more sodium ion insertion sites and adsorption sites, improving sodium storage capacity. At the same time, the few-layer diffusion path can accelerate the transport of sodium ions and enhance rate performance, resulting in molybdenum disulfide precursor powder.

[0058] (2) 1.5g of perylene-3,4,9,10-tetracarboxylic dianhydride and 1.5g of phenolic resin were ultrasonically dispersed uniformly in 15mL of ethanol solution. Boric acid was added at a rate of 0.3g. Boric acid, as a crosslinking agent, can enhance the thermal stability of phenolic resin, promote the formation of more closed-cell structures, and improve the first-cycle coulombic efficiency. The uniformly mixed solution was then dried in an oven at 80℃ for 18h. The resulting red powder was placed in a tube furnace and pyrolyzed at 1000℃ for 0.75h under an argon atmosphere. After cooling to room temperature, perylene-3,4,9,10-tetracarboxylic dianhydride was obtained. - The high-temperature pyrolysis of tetracarboxylic acid dianhydride releases carbon monoxide and carbon dioxide during carbonization, forming uniform micropores. The pyrolysis of phenolic resin contributes to the mesopores, thus forming a pore structure that stores sodium in micropores and transfers mass in mesopores, resulting in high capacity and excellent rate performance. Meanwhile, boric acid decomposes into B2O3 at high temperature, with some B atoms replacing C in the carbon skeleton to form BC bonds. Boron doping not only expands the carbon interlayer spacing, which is beneficial for the insertion and extraction of sodium ions, but also enhances the stability of the carbon skeleton and suppresses volume expansion during cycling, resulting in boron-doped porous hard carbon materials.

[0059] (3) Ferric nitrate nonahydrate, cobalt nitrate hexahydrate, sodium thiosulfate, the molybdenum disulfide precursor powder mentioned in step (1), and the boron-doped porous hard carbon material mentioned in step (2) are ground and mixed. After being ground evenly, glucose is added. The amount of glucose added is 0.9g. The pyrolysis of glucose can form an amorphous carbon shell coating layer, which inhibits the volume expansion of FeS / Co9S8 during charging and discharging, reduces the dissolution of polysulfides in the electrolyte, and improves cycle stability. Under an argon flow, the impurities are first removed at 290℃ for 0.75h, and then sulfurized at 550℃ for 1.5h. After cooling to room temperature, the powder is evenly spread on the sample stage and treated with argon plasma for 12.5min at a power of 70W and a pressure of 20Pa. Through the pyrolysis composite process, a boron-doped porous hard carbon material is formed as the skeleton, loaded with FeS and Co9S8. The core structure consists of 8 and MoS2 nanoparticles coated with a conductive carbon layer. The three-dimensional conductive network constructed from boron-doped porous hard carbon material provides a fast electron transport channel. Its pore structure effectively buffers the volume strain of sodium ion insertion and extraction. FeS, Co9S8, and MoS2 serve as active phases, synergistically enhancing sodium storage capacity. The carbon coating layer reduces direct contact between the active material and the electrolyte, inhibits the volume expansion of nanoparticles, and improves cycle stability. Plasma treatment directionally introduces sulfur vacancies into MoS2. The uncoordinated Mo atoms around the sulfur vacancies become new adsorption sites for sodium ions, which is beneficial to improving capacity. Sulfur vacancies introduce intermediate energy levels into the band gap of MoS2, narrowing the band gap, promoting electron transition and enhancing conductivity. It can also graphitize part of the carbon layer, reducing charge transfer impedance and improving rate performance, resulting in a porous hard carbon-based ternary composite material.

[0060] This embodiment provides a method for preparing a sodium-ion battery pitch-based anode material, specifically including the following steps:

[0061] S1. Dissolve 1.5g of asphalt powder with a softening point of 90℃ in 75mL of o-dichlorobenzene solvent, add 2.0g of diethoxymethane and 5.5g of aluminum chloride, then add thiourea and zinc chloride, each added in 1.5g amounts. The amino groups of thiourea condense with the aromatic rings of the asphalt to form an N / S co-doped structure, which stabilizes the carbon skeleton and increases active sites, thereby improving specific capacity and cycling stability. Zinc chloride acts as a template and pore-forming agent, forming microporous and mesoporous structures, optimizing transport paths, and enhancing rate performance. Then, reflux the reaction at 110℃ for 7h, centrifuge, collect the precipitate and place it in a Soxhlet extractor. Wash with methanol for 10h, then boil in a 3.6% hydrochloric acid solution for 1.5h. After drying, the asphalt was washed with 1,2-dichloroethane solvent for 2.5 hours, dried in a vacuum oven at 80°C for 12 hours, and then transferred to a tube furnace. The furnace was first heated to 250°C and held at that temperature for 0.75 hours, then heated to 650°C and held at that temperature for 0.75 hours, and finally heated to 900°C and carbonized for 1.5 hours. Under the catalysis of aluminum chloride, diethoxymethane condensed with asphalt to form a three-dimensional cross-linked network, which reduced the risk of structural collapse in the graphitized region of the asphalt and improved its stability. Further N / S doping and pore-forming treatment of the cross-linked network improved the graphitic microcrystalline structure of the asphalt, widened the interlayer spacing, enriched the active sites, facilitated the insertion and extraction of sodium ions, and also alleviated volume strain. This effectively enhanced the specific capacity, rate performance and cycle stability of the material, resulting in modified asphalt material.

[0062] S2. Disperse the porous hard carbon-based ternary composite material in 200 mL of N-methylpyrrolidone solvent and sonicate for 25 min to form a porous hard carbon-based ternary composite material dispersion. Set aside. Add the modified asphalt material from step S1 to 100 mL of N-methylpyrrolidone solvent and heat to 70 °C to promote dissolution, forming a modified asphalt material solution. Set aside. Then mix the porous hard carbon-based ternary composite material dispersion and the modified asphalt material solution, magnetically stir for 3 h, sonicate for 0.75 h, and dry at 60 °C to evaporate the solvent. The resulting solid mixture is carbonized at 700 °C for 2 h under an argon flow. Through the combination of the porous hard carbon-based ternary composite material and the modified asphalt material, a composite material is formed. A core-shell-pore three-level structured anode material is developed, with a porous hard carbon-based ternary composite material as the active core and modified bitumen material generating a derived carbon shell. The pore structure between the active core and the carbon shell is tightly and stably filled, exhibiting abundant hierarchical channels. The active core and pore structure provide sufficient sodium ion adsorption sites, while the three-dimensional conductive network and hierarchical channels optimize rate performance. The core-shell structure provides a buffer space for sodium ion insertion, and the outer cross-linked bitumen network inhibits carbon layer stripping, thereby effectively mitigating volume expansion and enhancing structural stability. This significantly improves the sodium storage capacity, rate performance, and cycle stability of the bitumen material, optimizing battery performance and yielding a bitumen-based anode material for sodium-ion batteries.

[0063] Example 4

[0064] This embodiment proposes a sodium-ion battery asphalt-based anode material, comprising the following components by weight: 60 parts of porous hard carbon-based ternary composite material and 40 parts of modified asphalt material.

[0065] The porous hard carbon-based ternary composite material comprises the following components in parts by weight: 10 parts of molybdenum disulfide precursor powder, 70 parts of boron-doped porous hard carbon material, 8 parts of iron nitrate nonahydrate, 3 parts of cobalt nitrate hexahydrate, 10 parts of sodium thiosulfate, and 8 parts of glucose.

[0066] Modified bitumen material, comprising the following components in parts by weight: 20 parts bitumen, 10 parts diethoxymethane, 80 parts aluminum chloride, 10 parts thiourea, and 20 parts zinc chloride.

[0067] The preparation method of porous hard carbon-based ternary composite materials specifically includes the following steps:

[0068] (1) Dissolve hydroxyethyl ethylenediamine triacetic acid (HEAT) and 2.5 g ammonium molybdate in 20 mL of deionized water. The amount of HEAT added is 3.8 g. HEAT partially decomposes under high temperature hydrothermal conditions. Its residual oxygen- and nitrogen-containing groups will compete with sulfur in molybdenum disulfide for coordination, inducing the formation of sulfur vacancies and improving the electrochemical activity and electronic conductivity of the material. During magnetic stirring, 28% ammonia water is added to adjust the pH to 8.0. Then, 11.5 g ammonium sulfide is added and stirred evenly. Then, it is transferred to a high-pressure reactor and heated at 200 °C. After heating for 6 hours and centrifuging, the precipitate was washed five times with deionized water and ethanol solution, and finally dried under vacuum at 80°C. In this process, the long-chain molecular structure of hydroxyethyl ethylenediamine triacetic acid can be adsorbed on specific crystal planes of molybdenum disulfide crystals, inhibiting vertical stacking and promoting lateral growth, thereby forming ultrathin nanosheets with an S-Mo-S three-layer sandwich structure. This ultrathin layered structure and sulfur vacancies provide more sodium ion insertion sites and adsorption sites, improving sodium storage capacity. At the same time, the few-layer diffusion path can accelerate sodium ion transport and enhance rate performance, resulting in molybdenum disulfide precursor powder.

[0069] (2) 2.0 g of perylene-3,4,9,10-tetracarboxylic dianhydride and 1.0 g of phenolic resin were ultrasonically dispersed uniformly in 15 mL of ethanol solution. Boric acid was added at a rate of 0.1 g. Boric acid, as a crosslinking agent, can enhance the thermal stability of phenolic resin, promote the formation of more closed-cell structures, and improve the first-cycle coulombic efficiency. The uniformly mixed solution was then dried in an oven at 80 °C for 16 h. The resulting red powder was placed in a tube furnace and pyrolyzed at 1100 °C for 0.5 h under an argon atmosphere. After cooling to room temperature, perylene-3,4,9,10-tetracarboxylic dianhydride was obtained. - The high-temperature pyrolysis of tetracarboxylic acid dianhydride releases carbon monoxide and carbon dioxide during carbonization, forming uniform micropores. The pyrolysis of phenolic resin contributes to the mesopores, thus forming a pore structure that stores sodium in micropores and transfers mass in mesopores, resulting in high capacity and excellent rate performance. Meanwhile, boric acid decomposes into B2O3 at high temperature, with some B atoms replacing C in the carbon skeleton to form BC bonds. Boron doping not only expands the carbon interlayer spacing, which is beneficial for the insertion and extraction of sodium ions, but also enhances the stability of the carbon skeleton and suppresses volume expansion during cycling, resulting in boron-doped porous hard carbon materials.

[0070] (3) Ferric nitrate nonahydrate, cobalt nitrate hexahydrate, sodium thiosulfate, the molybdenum disulfide precursor powder mentioned in step (1), and the boron-doped porous hard carbon material mentioned in step (2) are ground and mixed. After thorough grinding and uniform mixing, glucose is added. The amount of glucose added is 0.8g. The pyrolysis of glucose can form an amorphous carbon shell coating layer, which inhibits the volume expansion of FeS / Co9S8 during charging and discharging, reduces the dissolution of polysulfides in the electrolyte, and improves cycle stability. Under an argon flow, the powder is first removed at 300℃ for 0.5h, then sulfided at 600℃ for 1h, cooled to room temperature, and finally the powder is evenly spread on the sample stage. It is then subjected to argon plasma treatment for 10min at a power of 80W and a pressure of 30Pa. Through the pyrolysis composite process, a composite material with boron-doped porous hard carbon material as the skeleton and loaded with FeS, Co9S8 and The core structure of MoS2 nanoparticles coated with a conductive carbon layer, along with the three-dimensional conductive network constructed from boron-doped porous hard carbon material, provides a fast electron transport channel. Its pore structure effectively buffers the volume strain of sodium ion insertion and extraction. FeS, Co9S8, and MoS2 serve as active phases, synergistically enhancing sodium storage capacity. The carbon coating reduces direct contact between the active material and the electrolyte, inhibits the volume expansion of the nanoparticles, and improves cycle stability. Plasma treatment directionally introduces sulfur vacancies into MoS2, and the uncoordinated Mo atoms around the sulfur vacancies become new adsorption sites for sodium ions, which is beneficial to improving capacity. Sulfur vacancies introduce intermediate energy levels into the band gap of MoS2, narrowing the band gap, promoting electron transitions and enhancing conductivity. It can also graphitize part of the carbon layer, reducing charge transfer impedance and improving rate performance, resulting in a porous hard carbon-based ternary composite material.

[0071] This embodiment provides a method for preparing a sodium-ion battery pitch-based anode material, specifically including the following steps:

[0072] S1. Dissolve 2.0 g of asphalt powder with a softening point of 100 °C in 75 mL of o-dichlorobenzene solvent, add 1.0 g of diethoxymethane and 8.0 g of aluminum chloride, then add thiourea and zinc chloride, with the amounts of thiourea and zinc chloride being 1.0 g and 2.0 g, respectively. The amino groups of thiourea condense with the aromatic rings of the asphalt to form an N / S co-doped structure, which stabilizes the carbon skeleton and increases the active sites, thereby improving the specific capacity and cycling stability. Zinc chloride acts as a template agent and pore-forming agent, forming microporous and mesoporous structures, optimizing the transport path, and is beneficial for enhancing rate performance. Then, reflux the reaction at 120 °C for 6 h, centrifuge, collect the precipitate and place it in a Soxhlet extractor, wash with methanol for 8 h, and place it in a 3.6% hydrochloric acid solution. After boiling for 1 hour and drying, the material was washed with 1,2-dichloroethane solvent for 2 hours and dried in a vacuum oven at 80°C for 12 hours. Then, it was transferred to a tube furnace, heated to 300°C for 0.5 hours, then heated to 800°C for 0.5 hours, and finally heated to 1000°C for 1 hour for carbonization. Under the catalysis of aluminum chloride, diethoxymethane condensed with asphalt to form a three-dimensional cross-linked network, which reduced the risk of structural collapse in the graphitized region of the asphalt and improved its stability. Further N / S doping and pore-forming treatment of the cross-linked network improved the graphitic microcrystalline structure of the asphalt, widened the interlayer spacing, enriched the active sites, facilitated the insertion and extraction of sodium ions, and alleviated volume strain. This effectively enhanced the specific capacity, rate performance and cycle stability of the material, resulting in modified asphalt material.

[0073] S2. Disperse the porous hard carbon-based ternary composite material in 200 mL of N-methylpyrrolidone solvent and sonicate for 20 min to form a porous hard carbon-based ternary composite material dispersion, set aside. Add the modified asphalt material from step S1 to 100 mL of N-methylpyrrolidone solvent and heat to 80 °C to promote dissolution, forming a modified asphalt material solution, set aside. Then mix the porous hard carbon-based ternary composite material dispersion and the modified asphalt material solution, magnetically stir for 2 h, sonicate for 0.5 h, and dry at 60 °C to evaporate the solvent. The resulting solid mixture is carbonized at 800 °C for 1 h under an argon flow. Through the combination of the porous hard carbon-based ternary composite material and the modified asphalt material, a core is formed. The anode material features a three-tiered shell-pore structure. A porous hard carbon-based ternary composite material serves as the active core, while modified bitumen material generates a derived carbon shell. The pore structure between the active core and the carbon shell is tightly and stably filled, exhibiting abundant hierarchical channels. The active core and pore structure provide ample sodium ion adsorption sites. The three-dimensional conductive network and hierarchical channels optimize rate performance. The core-shell structure provides a buffer space for sodium ion insertion, and the outer cross-linked bitumen network inhibits carbon layer stripping, effectively mitigating volume expansion and enhancing structural stability. This significantly improves the sodium storage capacity, rate performance, and cycle stability of the bitumen material, optimizing battery performance and yielding a bitumen-based anode material for sodium-ion batteries.

[0074] Comparative Example 1

[0075] This comparative example provides a sodium-ion battery pitch-based anode material, which differs from Example 1 in that the porous hard carbon-based ternary composite material does not contain boron-doped porous hard carbon material; the preparation method of the porous hard carbon-based ternary composite material does not include step (2); the preparation method of the sodium-ion battery pitch-based anode material is the same as that of Example 1.

[0076] Comparative Example 2

[0077] This comparative example provides a sodium-ion battery pitch-based anode material, which differs from Example 1 in that the porous hard carbon-based ternary composite material does not contain molybdenum disulfide precursor powder or glucose; the preparation method of the porous hard carbon-based ternary composite material does not include step (1), and glucose is not added in step (3); the preparation method of the sodium-ion battery pitch-based anode material is the same as that of Example 1.

[0078] Comparative Example 3

[0079] This comparative example provides a sodium-ion battery asphalt-based anode material, which differs from Example 1 in that the modified asphalt material does not contain diethoxymethane, thiourea, and zinc chloride; the preparation method of the porous hard carbon-based ternary composite material is the same as that of Example 1; and diethoxymethane, thiourea, and zinc chloride are not added in step S1 of the preparation method of the sodium-ion battery asphalt-based anode material.

[0080] Experimental Example 1

[0081] Capacity Experiment

[0082] Test samples: Sodium-ion battery pitch-based anode materials prepared in Examples 1-4 and Comparative Examples 1-3.

[0083] Test Method: The test sample, PVDF, and Super-P conductive carbon black were mixed in NMP at a mass ratio of 8:1:1 to form a slurry, which was then coated onto copper foil. The mixture was then dried in a vacuum drying oven at 80°C for 1 hour, followed by drying at 100°C for 8 hours. The slurry was then cut into electrode sheets with a diameter of 12 mm. The coating mass was weighed and calculated, and 80% of this mass was used as the active material mass (g). The electrode sheets, glass fiber separator, sodium sheet, and 1 mol / L NaClO4 electrolyte (EC+DEC+FEC, EC:DEC volume ratio 1:1, FEC volume percentage 5%) were assembled into a button cell in that order. Charge-discharge tests were performed using a CT2001A blue battery testing system. The cells were first activated at 0.1C for 3 cycles, then tested at 0.2C for 5 cycles. The last 3 stable values ​​were recorded, and the discharge capacity (mAh) was recorded. The specific capacity (mAh / g) was calculated using the following formula:

[0084] Specific capacity (mAh / g) = Discharge capacity (mAh) / Mass of active material (g).

[0085] Figure 2 The figures show the specific capacity results for Examples 1-4 and Comparative Examples 1-3. As shown, the specific capacity of Examples 1-4 is 567-652 mAh / g, indicating a relatively high specific capacity; the specific capacity of Comparative Examples 1-3 is 372-473 mAh / g, indicating a relatively low specific capacity. The porous hard carbon-based ternary composite material of Comparative Example 1 does not contain boron-doped porous hard carbon material, thus failing to provide a high-capacity framework and hindering the loading of FeS, Co9S8, and MoS2 nanoparticles, resulting in a low specific capacity. The porous hard carbon-based ternary composite material of Comparative Example 2 does not contain molybdenum disulfide precursor powder or glucose, thus failing to increase sodium storage capacity through ultrathin nanosheets with an S-Mo-S three-layer sandwich structure, and also failing to form a conductive carbon layer, resulting in a low specific capacity. The modified asphalt material of Comparative Example 3 does not contain diethoxymethane, thiourea, or zinc chloride, thus failing to form a three-dimensional cross-linked network with asphalt, and also failing to introduce N / S doping and play a pore-forming role, which is detrimental to enriching active sites, resulting in a low specific capacity.

[0086] Experiment Example 2

[0087] Magnification Experiment

[0088] Test samples: Sodium-ion battery pitch-based anode materials prepared in Examples 1-4 and Comparative Examples 1-3.

[0089] Test method: The test sample, PVDF, and Super-P conductive carbon black were mixed in NMP at a mass ratio of 8:1:1 to form a slurry, which was then coated onto copper foil. The mixture was then dried in a vacuum drying oven at 80°C for 1 hour, followed by drying at 100°C for 8 hours. The resulting material was cut into electrode sheets with a diameter of 12 mm. The coating mass was weighed and calculated, and 80% of this mass was used as the active material mass (g). The electrode sheets, glass fiber separator, sodium sheet, and 1 mol / L NaClO4 electrolyte (EC+DEC+FEC, EC:DEC volume ratio of 1:1, FEC volume percentage of 5%) were then assembled into a button cell. Rate performance was tested at a current density of 0.1 and a 5C condition to obtain the discharge specific capacity (mAh / g). The discharge specific capacity retention rate (%) was then calculated based on the ratio of the two values.

[0090] Figure 3The figures show the discharge capacity retention rates of Examples 1-4 and Comparative Examples 1-3. As shown, the discharge capacity retention rate of Examples 1-4 is 80-85%, indicating good rate performance. The discharge capacity retention rate of Comparative Examples 1-3 is 63-71%, indicating poor rate performance. The porous hard carbon-based ternary composite material of Comparative Example 1 does not contain boron-doped porous hard carbon material, making it impossible to construct a three-dimensional conductive network, which is detrimental to providing fast electron transport channels, resulting in poor rate performance. The porous hard carbon-based ternary composite material of Comparative Example 2 does not contain molybdenum disulfide precursor powder or glucose, making it impossible to directionally introduce sulfur vacancies into MoS2 through plasma treatment to promote electron transitions, nor can it suppress nanoparticle aggregation through a carbon coating layer, which is detrimental to optimizing ion diffusion paths, resulting in poor rate performance. The modified bitumen material of Comparative Example 3 does not contain diethoxymethane, thiourea, or zinc chloride, making it impossible to form a three-dimensional conductive network and multi-level channels, resulting in poor rate performance.

[0091] Experimental Example 3

[0092] Cyclic stability experiment

[0093] Test samples: Sodium-ion battery pitch-based anode materials prepared in Examples 1-4 and Comparative Examples 1-3.

[0094] Test method: The test sample, PVDF, and Super-P conductive carbon black were mixed in NMP at a mass ratio of 8:1:1 to form a slurry, which was then coated onto copper foil. The mixture was then dried in a vacuum drying oven at 80°C for 1 hour, followed by drying at 100°C for 8 hours. The slurry was then cut into electrode sheets with a diameter of 12 mm. The coating mass was weighed and calculated, and 80% of the coating mass was used as the active material mass (g). The electrode sheets, glass fiber separator, sodium sheet, and 1 mol / L NaClO4 electrolyte (EC+DEC+FEC, EC:DEC volume ratio of 1:1, FEC volume percentage of 5%) were assembled into a button cell in sequence. A constant current charge-discharge test was performed under a current density of 1C. The capacity retention rate (%) was calculated by the discharge specific capacity after 1000 cycles.

[0095] Figure 4The figures show the capacity retention rates after 1000 cycles for Examples 1-4 and Comparative Examples 1-3. As shown, the capacity retention rate after 1000 cycles for Examples 1-4 is 85-90%, indicating good cycle stability. The capacity retention rate after 1000 cycles for Comparative Examples 1-3 is 70-78%, indicating moderate cycle stability. The porous hard carbon-based ternary composite material in Comparative Example 1 does not contain boron-doped porous hard carbon material, making it impossible to enhance structural stability through a porous framework material. This also hinders buffering the volume expansion during sodium ion insertion and extraction, resulting in moderate cycle stability. Comparative Example 2... The porous hard carbon-based ternary composite material does not contain molybdenum disulfide precursor powder or glucose, so it cannot buffer the volume expansion stress through the layered structure of ultrathin nanosheets, nor can it suppress the volume expansion of nanoparticles through the carbon coating layer, resulting in mediocre cycle stability. The modified asphalt material in Comparative Example 3 does not contain diethoxymethane, thiourea, or zinc chloride, so it cannot condense with asphalt to form a three-dimensional cross-linked network, increasing the risk of structural collapse in the graphitized region of the asphalt. It also cannot introduce N / S doping sites or play a pore-forming role, which is not conducive to widening the interlayer spacing, and thus not conducive to alleviating volume strain, resulting in mediocre cycle stability.

[0096] The above experimental results show that the specific capacity, rate performance, and cycle stability of Examples 1-4 of the present invention are significantly better than those of Comparative Examples 1-3. Among them, Example 1, which uses porous hard carbon-based ternary composite material and modified asphalt material, has a higher specific capacity, better rate performance, and better cycle stability. Combining porous hard carbon-based ternary composite material with modified asphalt material forms an asphalt-based negative electrode material with porous hard carbon-based ternary composite material as the active core, modified asphalt material as the derived carbon shell, and rich multi-level pore structure, which significantly improves the sodium storage capacity, rate performance, and cycle stability of asphalt material.

[0097] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

[0098] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A sodium-ion battery pitch-based anode material, characterized in that: The sodium-ion battery asphalt-based anode material comprises the following components in parts by weight: 50-60 parts of porous hard carbon-based ternary composite material and 40-50 parts of modified asphalt material; the porous hard carbon-based ternary composite material comprises the following components in parts by weight: 10-15 parts of molybdenum disulfide precursor powder, 60-70 parts of boron-doped porous hard carbon material, 8-10 parts of iron nitrate nonahydrate, 3-5 parts of cobalt nitrate hexahydrate, 8-10 parts of sodium thiosulfate, and 8-10 parts of glucose; the modified asphalt material comprises the following components in parts by weight: 10-20 parts of asphalt, 10-30 parts of diethoxymethane, 30-80 parts of aluminum chloride, 10-20 parts of thiourea, and 10-20 parts of zinc chloride.

2. A method for preparing a sodium-ion battery pitch-based negative electrode material according to claim 1, characterized in that: Specifically, the following steps are included: S1. Dissolve 1.0-2.0g of asphalt powder with a softening point of 80-100℃ in 75mL of o-dichlorobenzene solvent, add 1.0-3.0g of diethoxymethane and 3.0-8.0g of aluminum chloride, then add thiourea and zinc chloride, and reflux at 100-120℃ for 6-8h. Centrifuge, collect the precipitate and place it in a Soxhlet extractor. Wash with methanol for 8-12h, boil in 3.6% hydrochloric acid solution for 1-2h, dry, wash with 1,2-dichloroethane solvent for 2-3h, dry in a vacuum oven at 80℃ for 12h, and then transfer to a tube furnace. First, raise the temperature to 200-300℃ and hold for 0.5-1h, then raise the temperature to 500-800℃ and hold for 0.5-1h, and finally raise the temperature to 800-1000℃ for carbonization treatment for 1-2h to obtain modified asphalt material. S2. Disperse the porous hard carbon-based ternary composite material in 200 mL of N-methylpyrrolidone solvent, and sonicate for 20-30 min to form a porous hard carbon-based ternary composite material dispersion, which is set aside. Add the modified asphalt material described in step S1 to 100 mL of N-methylpyrrolidone solvent, heat to 60-80℃ to promote dissolution, and form a modified asphalt material solution, which is set aside. Then mix the porous hard carbon-based ternary composite material dispersion and the modified asphalt material solution, stir magnetically for 2-4 h, sonicate for 0.5-1 h, and dry at 60℃ to evaporate the solvent. The resulting solid mixture is carbonized at 600-800℃ for 1-3 h under an argon flow to obtain the sodium-ion battery asphalt-based negative electrode material.

3. The method for preparing the sodium-ion battery pitch-based negative electrode material according to claim 2, characterized in that: In step S1, the amount of thiourea and zinc chloride added is 1.0-2.0 g each.

4. The method for preparing the sodium-ion battery pitch-based negative electrode material according to claim 3, characterized in that: The preparation method of the porous hard carbon-based ternary composite material specifically includes the following steps: (1) Dissolve hydroxyethyl ethylenediamine triacetic acid and 2.0-2.5g ammonium molybdate in 20mL of deionized water. During magnetic stirring, add 28% ammonia water to adjust the pH to 7.0-8.

0. Then add 9.5-11.5g ammonium sulfide, stir evenly, and then transfer to a high-pressure reactor. Heat at 180-200℃ for 6-12h, centrifuge, and wash the precipitate with deionized water and ethanol solution 3-5 times in sequence. Finally, vacuum dry at 60-80℃ to obtain molybdenum disulfide precursor powder. (2) 1.0-2.0g of perylene-3,4,9,10-tetracarboxylic acid dianhydride and 1.0-2.0g of phenolic resin were ultrasonically dispersed in 15mL of ethanol solution. Boric acid was added, and the uniformly mixed solution was placed in an oven at 80℃ and dried for 16-20h. The resulting red powder was placed in a tube furnace and pyrolyzed at 900-1100℃ for 0.5-1h under an argon flow. After cooling to room temperature, boron-doped porous hard carbon material was obtained. (3) The iron nitrate nonahydrate, cobalt nitrate hexahydrate, sodium thiosulfate, the molybdenum disulfide precursor powder described in step (1), and the boron-doped porous hard carbon material described in step (2) are ground and mixed. After being ground evenly, glucose is added. The mixture is first purified at 280-300℃ for 0.5-1h under an argon flow, then sulfurized at 500-600℃ for 1-2h. After cooling to room temperature, the powder is evenly spread on the sample stage and treated with argon plasma for 10-15min at a power of 60-80W and a pressure of 10-30Pa to obtain a porous hard carbon-based ternary composite material.

5. The method for preparing the sodium-ion battery pitch-based negative electrode material according to claim 4, characterized in that: In step (1), the amount of hydroxyethyl ethylenediamine triacetic acid added is 3.8-4.2g.

6. The method for preparing the sodium-ion battery pitch-based negative electrode material according to claim 5, characterized in that: In step (2), the amount of boric acid added is 0.1-0.5g.

7. The method for preparing the sodium-ion battery pitch-based negative electrode material according to claim 6, characterized in that: In step (3), the amount of glucose added is 0.8-1.0g.

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