Multi-cavity mesoporous carbon nanosphere battery material as well as preparation method and application thereof

Abstract

The invention discloses a multi-cavity mesoporous carbon nanosphere battery material and a preparation method and application thereof, and belongs to the technical field of ion batteries, the method comprises the following steps: mixing a cosolvent and a surfactant, and stirring until the cosolvent and the surfactant are dissolved; adding a carbon source monomer, and stirring until dissolving; adding a pore-foaming agent, and stirring to form a suspension; and finally, adding a hydrogen bond catalyst, and after the stirring reaction is finished, washing, freeze-drying and carbonizing to obtain the multi-cavity mesoporous carbon nanosphere battery material. The problems of poor micelle stability and low repeatability of a traditional soft template method are solved through cooperative regulation and control of catalysis of the hydrogen bond catalyst and precise assembly time. By simply controlling the reaction time, a product with the multi-cavity structure reaching 65.3%-92.5% is stably and repeatedly prepared and far exceeds 31.7% of that of a non-catalytic system, and precise customization of the microstructure of the material is achieved. The multi-cavity structure can better buffer the volume change caused by sodium ion intercalation / deintercalation in the charging and discharging process, and is beneficial to maintaining the structural integrity of the electrode material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ion batteries, and particularly relates to a multi-cavity mesoporous carbon nanosphere battery material and a preparation method and application thereof. BACKGROUND

[0002] In the field of electrochemical energy storage, ion batteries occupy a dominant position, and the performance of the negative electrode material, as a core component of the battery, directly determines the energy density, cycle life and safety of the battery. At present, the negative electrode materials used in sodium ion batteries (SIBs) and lithium ion batteries (LIBs) mainly cover two categories: carbon-based materials and metal oxide materials. Metal oxide negative electrodes (such as transition metal oxides) have the advantages of high theoretical specific capacity, abundant resources, low cost and environmental friendliness, but they often undergo large volume changes during charging and discharging, leading to material structure collapse, accelerating material aging, and triggering irreversible side reactions, which seriously restricts their cycle stability. In contrast, carbon-based materials have become one of the most widely researched and applied negative electrode materials due to their wide range of raw materials (obtainable through plant carbonization or organic synthesis), relatively green preparation process, excellent structural stability and other characteristics. The controllability of the microcrystalline / amorphous structure and surface chemical properties of carbon materials also enables them to adapt to the embedding / extraction and surface storage behavior of alkali metal ions (such as Na + , Li + ) of different sizes, thus showing broad application prospects in SIBs and LIBs.

[0003] Among the numerous carbon-based negative electrode materials, mesoporous carbon nanospheres (MCS) have attracted much attention due to their unique structural advantages. MCS have high specific surface area, rich controllable pore size distribution, highly ordered pore structure, short ion diffusion path and good active material loading capacity, which are beneficial to electrolyte infiltration and rapid ion transport, thus improving the rate performance and reversible capacity of the battery. In recent years, researchers have been committed to optimizing the synthesis path of MCS, and significant progress has been made in morphology control. Various structurally regular MCS materials have been successfully applied to sodium ion battery negative electrodes and have shown excellent electrochemical potential.

[0004] However, the synthesis and application of MCS still face several challenges. In terms of material preparation, the widely used soft template method (based on micellar self-assembly) can achieve precise control over pore size and surface morphology, but this route is usually cumbersome, the template system has poor stability, and reproducibility is low, limiting its feasibility for large-scale preparation. In terms of battery applications, most reported MCS materials are of high specific surface area. These materials are prone to triggering more side reactions such as electrolyte decomposition during sodium storage, leading to instability of the solid electrolyte interface (SEI), which in turn affects the structural integrity and long-term cycling performance of the material. In contrast, low specific surface area MCS shows significant potential in suppressing side reactions, improving initial coulombic efficiency, and cycling stability, but related synthesis strategies and research on actual sodium storage performance are still relatively lacking. Therefore, systematically conducting research on the structural control of MCS, developing simple and controllable synthesis methods, and deeply exploring its structure-property relationship in energy storage systems such as SIBs are of great significance for promoting the practical application of high-performance carbon-based anode materials. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a multi-cavity mesoporous carbon nanosphere battery material, its preparation method and application, so as to solve the technical problems of poor structural controllability, harsh reaction conditions and insufficient electrochemical performance in the preparation of existing multi-cavity mesoporous carbon nanospheres.

[0006] To achieve the above objectives, the present invention employs the following technical solution: This invention discloses a method for preparing a multi-cavity mesoporous carbon nanosphere battery material, comprising: The cosolvent and surfactant were mixed and stirred until dissolved; the carbon source monomer was added and stirred until dissolved; the pore-forming agent was added and stirred until a suspension was formed; finally, the hydrogen bonding catalyst was added, and after the reaction was completed, the mixture was washed, freeze-dried, and carbonized to obtain a multi-cavity mesoporous carbon nanosphere battery material.

[0007] Preferably, the co-solvent is prepared by mixing 20-30 mL of anhydrous ethanol with 70-80 mL of deionized water; The surfactant was prepared by compounding 0.7-0.8g of P123 and 0.2-0.3g of F127.

[0008] Preferably, the carbon source monomer is anhydrous phloroglucinol; the porogen is mesitylene, and the addition rate of the porogen is 1-2 drops / second; the hydrogen bonding catalyst is ethylenediamine monohydrate.

[0009] Preferably, the ratio of cosolvent, surfactant, carbon source monomer, porogen and hydrogen bonding catalyst is (90-110) mL: (0.9-1.1) g: (0.5-0.6) g: (2-3) mL: (260-270) μL.

[0010] Preferably, the stirring speed is 400-600 rpm and the stirring time is 10-20 min.

[0011] Preferably, the stirring reaction conditions include: stirring at a speed of 400-600 rpm at room temperature for 12-36 hours.

[0012] Preferably, the washing conditions include: centrifuging at 8000-10000 rpm for 10-15 min, discarding the supernatant, and then washing the precipitate 3-5 times alternately with anhydrous ethanol and deionized water. The freeze-drying conditions include: freeze-vacuum drying at -60℃ and a vacuum degree ≤10Pa for 12-24 h.

[0013] Preferably, the carbonization conditions include: introducing high-purity nitrogen as a protective gas with a flow rate of 40-60 mL / min; heating from room temperature to 700-900℃ at a heating rate of 1-5℃ / min; and holding the temperature for carbonization for 2-3 hours.

[0014] This invention also discloses a multi-cavity mesoporous carbon nanosphere battery material, prepared using the above-described method; the specific surface area of ​​the multi-cavity mesoporous carbon nanosphere battery material is 98-1215 m². 2 ·g -1 The total pore volume is 1.45-1.82 cm³. 3 ·g -1 The average mesopore size is 14.1–15.8 nm; the multi-structure ratio is 65.3%–92.5%; the specific capacitance at a current density of 1 A / g is 228–315 F / g; and the capacity retention after 5000 cycles is 85.7%–92.3%.

[0015] The present invention also discloses the application of the multi-cavity mesoporous carbon nanosphere battery material prepared by the above-mentioned method in sodium-ion batteries.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for preparing multi-cavity mesoporous carbon nanosphere battery materials. First, a co-solvent and surfactant are mixed and dissolved. Then, a carbon source monomer is added and dissolved, followed by the introduction of a pore-forming agent to form a suspension. Finally, a hydrogen-bonding catalyst is added to initiate the reaction. The mixture is then washed, freeze-dried, and carbonized to obtain multi-cavity mesoporous carbon nanospheres. The co-solvent and surfactant form a homogeneous solution, and the addition of the carbon source monomer provides a precursor for subsequent carbon framework construction. The pore-forming agent is introduced into the system at a controllable rate, forming a pore template within the micelles through intermolecular forces. The addition of the hydrogen-bonding catalyst induces the formation of a directional hydrogen bond network between the surfactant and the carbon source monomer, achieving precise micelle assembly within a predetermined time. Subsequent processing removes the template agent and carbonizes the material, ultimately forming mesoporous carbon nanospheres with a multi-cavity structure. The synergistic effect between these steps effectively solves the technical challenges of poor micelle stability and uncontrollable multi-cavity structure. This method achieves controllable preparation of multi-cavity mesoporous carbon nanospheres, and the resulting material possesses a stable hierarchical pore structure, effectively mitigating the volume expansion problem during sodium ion insertion / extraction. The preparation process requires no complex equipment or highly corrosive reagents, reducing energy consumption and avoiding environmental pollution. This method provides a feasible technical path for the large-scale production of high-performance sodium-ion battery anode materials.

[0017] Furthermore, the cosolvent is prepared by mixing 20-30 mL of anhydrous ethanol with 70-80 mL of deionized water, and the surfactant is prepared by compounding 0.7-0.8 g of P123 and 0.2-0.3 g of F127. The mixing of anhydrous ethanol and deionized water in a specific ratio creates a polar gradient environment, allowing the polyoxyethylene segments in P123 and F127 molecules to fully interact with the aqueous phase, while the polypropylene oxide segments moderately combine with the ethanol phase, thus forming a uniformly dispersed micelle solution. When P123 and F127 are compounded in a ratio of 0.7-0.8 g and 0.2-0.3 g respectively, the hydrophilic-hydrophobic balance values ​​of the two surfactants are complementary, ensuring the stability of the micelle structure and regulating the micelle size and arrangement through the synergistic effect of block copolymers with different chain lengths, providing an ordered template for the subsequent directional polymerization of carbon source monomers. Stable construction and precise control of micelle templates were achieved, solving the problem of disordered pore structure caused by uneven surfactant dispersion in existing technologies, and providing key support conditions for morphology control of multi-cavity mesoporous carbon nanospheres.

[0018] Furthermore, the carbon source monomer is anhydrous phloroglucinol; the porogen is mesitylene, added at a rate of 1-2 drops / second; the hydrogen bonding catalyst is ethylenediamine monohydrate. After anhydrous phloroglucinol dissolves in the co-solvent, its phenolic hydroxyl groups form pre-assemblies with the polyoxyethylene chains of the surfactant through hydrogen bonding. When mesitylene is added slowly, it can be uniformly dispersed in the solution and inserted into the micelle core through hydrophobic interactions, controlling the expansion size of the micelles. The addition of ethylenediamine monohydrate catalyzes the hydrogen bond formation rate between the phenolic hydroxyl groups and the surfactant, enabling the micelles to complete ordered assembly within a specific time, forming a mesoporous carbon precursor with a multi-cavity structure. In this process, the synergistic effect of the porogen's addition rate and the catalyst ensures the uniformity and stability of the pore structure. This achieves the efficient and controllable synthesis of multi-cavity mesoporous carbon nanospheres. The hydrogen bonding catalyst accelerates the formation of intermolecular forces, ensuring that the micelles complete directional assembly within a predetermined time; the slow addition of the porogen avoids local supersaturation, resulting in a more uniform pore distribution. This technical solution effectively solves the problems of poor micelle stability and low proportion of multi-cavity structures in traditional methods, providing a reliable way to prepare high-performance sodium-ion battery anode materials.

[0019] Furthermore, the ratio of cosolvent, surfactant, carbon source monomer, porogen, and hydrogen-bonding catalyst was (90-110) mL : (0.9-1.1) g : (0.5-0.6) g : (2-3) mL : (260-270) μL; this achieved precise and synergistic control of the proportions of each component during micelle assembly, solving the problems of poor micelle stability and low proportion of multi-cavity structures caused by imbalanced ratios in existing technologies. The optimized cosolvent ratio ensured the full dissolution of the surfactant, the fixed ratio of the composite surfactant enhanced the strength of the micelle structure, the matching of the amounts of carbon source and porogen ensured uniform pore expansion, and the trace addition of the hydrogen-bonding catalyst directionally induced the formation of multi-cavity mesoporous structures.

[0020] Furthermore, the stirring speed was consistently 400-600 rpm, and the stirring time was consistently 10-20 min. This ensured that the surfactant molecules were fully dispersed and formed uniform micelles. During the carbon source monomer dissolution stage, the same stirring speed and time were maintained to promote the interaction between the monomer molecules and the micelle system. During the porogen addition stage, stirring for 10-20 min ensured that the porogen droplets were uniformly dispersed in the system, forming a stable suspension. This combination of parameters, through precise control of fluid dynamics, ensured that all components were uniformly mixed at the molecular scale, providing a stable precursor environment for subsequent hydrogen bond catalytic self-assembly.

[0021] Furthermore, the reaction conditions include: stirring at 400-600 rpm at room temperature for 12-36 hours; after the addition of the hydrogen-bonding catalyst, the stirrer is kept running at a constant speed within the 400-600 rpm range to maintain the reaction system in dynamic equilibrium. During this process, the surfactant micelles align under hydrogen bonding, and the carbon source monomer and porogen undergo ordered assembly at the micelle interface. The continuous stirring period of 12-36 hours provides a sufficient time window for micelle recombination and mesoporous structure stabilization, preventing incomplete assembly due to short reaction times and avoiding structural collapse caused by excessively long reaction times. This achieves efficient construction of multi-cavity structures of mesoporous carbon nanospheres, effectively improving the structural uniformity and electrochemical stability of the material. This technical solution optimizes the matching relationship between fluid dynamics conditions and reaction time window, enabling the micelle template to arrange in an orderly manner and form a stable hierarchical pore structure, providing an ideal precursor morphology basis for subsequent carbonization treatment.

[0022] Furthermore, the centrifugal washing stage controls the rotation speed and time to ensure separation efficiency while avoiding material agglomeration caused by excessive centrifugation. During alternating washing, ethanol preferentially dissolves organic residues, while deionized water removes inorganic impurities; the two work synergistically to improve material purity. The freeze-drying stage uses a low-temperature environment to inhibit ice crystal growth, combined with vacuum conditions to accelerate water sublimation, thereby preserving the material's multi-level porous structure. These three steps form a complete post-processing chain, ensuring that the product possesses high specific surface area and stable pore characteristics. This achieves efficient purification and structural protection of multi-cavity mesoporous carbon nanospheres, providing an ideal precursor for subsequent carbonization processing and ensuring that the final product has a uniform pore size distribution and a stable multi-cavity structure, thereby improving its cycle stability and specific capacitance performance in sodium-ion batteries.

[0023] Furthermore, the carbonization process is carried out in a closed tube furnace, with high-purity nitrogen gas introduced into the reaction chamber at a constant flow rate to create an oxygen-free environment. The temperature is then slowly increased using a programmed heating method, allowing the carbon precursor to gradually remove volatile components and complete the graphitization transformation. After reaching the target temperature, a constant temperature is maintained to promote the orderly recombination of the carbon framework and fix the multi-cavity mesoporous structure. This method solves the problems of material oxidation and decomposition, pore structure collapse, and insufficient graphitization during carbonization, achieving efficient preparation of multi-cavity mesoporous carbon nanospheres. The products possess uniform pore size distribution, high conductivity, and excellent structural stability.

[0024] This invention discloses a multi-cavity mesoporous carbon nanosphere battery material; it is prepared by mixing a co-solvent and a surfactant, then sequentially adding a carbon source monomer, a pore-forming agent, and a hydrogen-bonding catalyst, followed by stirring, washing, freeze-drying, and carbonization. The specific surface area of ​​this material is 98-1215 m². 2 ·g -1 The total pore volume is 1.45-1.82 cm³.3 ·g -1 The average mesopore size is 14.1-15.8 nm; the multi-structure ratio is 65.3%-92.5%; the specific capacitance at a current density of 1 A / g is 228-315 F / g; and the capacity retention after 5000 cycles is 85.7% to 92.3%. Through the synergistic effect of hydrogen-bonded catalysts and surfactants, a directional intermolecular hydrogen bond network is formed during micelle assembly, guiding the carbon source monomers to arrange themselves orderly around the micelles, ultimately forming a mesoporous carbon framework with a multi-cavity structure. During the carbonization stage, the control of the protective atmosphere and heating rate effectively preserves the multi-cavity mesoporous structure and improves the conductivity of the carbon material. The freeze-drying process avoids pore collapse, ensuring the integrity of the material's pore structure. This method solves the problem of insufficient electrochemical performance caused by the uncontrollable structure of existing mesoporous carbon materials, achieving efficient preparation of multi-cavity mesoporous carbon nanospheres. This material significantly improves cycle stability while maintaining high specific capacitance, meeting the requirements of sodium-ion batteries for long lifespan and high capacity anode materials. The combination of directional hydrogen bonding catalysis and precise assembly timing ensures the uniform distribution of the multi-cavity structure, thereby enhancing the structural stability and ion diffusion dynamics of the material.

[0025] This invention discloses a method for preparing multi-cavity mesoporous carbon nanospheres for use in sodium-ion batteries. When these multi-cavity carbon nanospheres operate in sodium-ion batteries, their multi-cavity structure reduces volume changes in the electrode material during charge and discharge by dispersing stress, while the mesoporous channels accelerate electrolyte wetting and sodium ion transport. The directional molecular arrangement induced by the hydrogen-bonded catalyst ensures uniform channel distribution, preventing electrode cracking caused by localized stress concentration. The stable micelle template formed by the surfactant complex system ensures channel connectivity after carbonization, maintaining the integrity of the highly conductive network. The defect sites and functional groups generated during carbonization enhance sodium ion adsorption capacity, improving reversible capacity. This effectively improves the cycle stability and rate performance of sodium-ion battery anode materials. The synergistic effect of the multi-cavity mesoporous structure inhibits electrode structure degradation, the uniform channel distribution improves ion transport efficiency, and the optimized surface chemical properties enhance sodium storage capacity, providing a feasible solution for the development of high-energy-density, long-cycle-life sodium-ion batteries. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0028] Unless otherwise specified, all the technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0029] In this invention, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0030] Unless otherwise specified, the components or preferred components involved in this invention can be combined with each other to form new technical solutions.

[0031] In this invention, unless otherwise specified, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "6~22" indicates that all real numbers between "6~22" have been listed in this document, and "6~22" is simply a shortened representation of these numerical combinations.

[0032] The "scope" disclosed in this invention can be in the form of a lower limit and an upper limit, and can be one or more lower limits and one or more upper limits, respectively.

[0033] In this invention, the term "and / or" as used herein refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0034] In this invention, unless otherwise stated, the various reactions or operation steps may be performed sequentially or in a particular order. Preferably, the reaction methods described herein are performed sequentially.

[0035] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this invention.

[0036] This invention provides a method for preparing a multi-cavity mesoporous carbon nanosphere battery material, comprising: mixing 20-30 mL of anhydrous ethanol with 70-80 mL of deionized water to prepare a co-solvent; compounding 0.7-0.8 g of P123 and 0.2-0.3 g of F127 to prepare a surfactant; mixing 90-110 mL of the co-solvent and 0.9-1.1 g of the surfactant, and stirring at 400-600 rpm for 10-20 min until dissolved; adding 0.5-0.6 g of the carbon source monomer anhydrous phloroglucinol, and stirring at 400-600 rpm for 10-20 min until dissolved; adding 2-3 mL of the pore-forming agent mesitylene, and stirring until a suspension is formed; finally, adding 260-270 μL of the hydrogen-bonding catalyst ethylenediamine monohydrate, and stirring at 400-600 rpm at room temperature for 12-36 h, followed by stirring at 8000-10000... Centrifuge and wash at rpm for 10-15 min, discard the supernatant, and then wash the precipitate 3-5 times alternately with anhydrous ethanol and deionized water. Freeze-dry under vacuum conditions of -60℃ and ≤10Pa for 12-24 h, and introduce high-purity nitrogen as a protective gas at a flow rate of 40-60 mL / min. Increase the temperature from room temperature to 700-900℃ at a rate of 1-5℃ / min. Carbonize at this temperature for 2-3 h to obtain the multi-cavity mesoporous carbon nanosphere battery material.

[0037] This invention uses a P123 / F127 compound surfactant as a soft template, anhydrous ethanol-deionized water as a co-solvent, anhydrous phloroglucinol (PG) as a carbon source monomer, mesitylene (TMB) as a pore-forming agent, and ethylenediamine monohydrate (EDAM) as a hydrogen bonding catalyst. Through the synergistic regulation of "EDAM-catalyzed hydrogen bond construction + precise micellar assembly time," a multi-cavity mesoporous carbon nanosphere battery material is prepared, successfully addressing the three major pain points in the preparation of existing multi-cavity mesoporous carbon nanospheres: poor structural controllability, harsh reaction conditions, and insufficient electrochemical performance. Results show that by inducing directional intermolecular hydrogen bonding through EDAM catalysis, combined with a precise assembly time of 12-36 hours, the proportion of multi-cavity structures is stably maintained at 81.7%-92.5% (Examples 1-5), far exceeding that of existing non-catalyst systems (31.7%, Comparative Example 1).

[0038] This invention has the following advantages: First, the multi-cavity structure offers strong controllability. Through EDAM catalysis to induce directional hydrogen bonding between molecules, combined with a precise assembly time of 12-36 hours, the proportion of the multi-cavity structure remains stable at 81.7%-92.5%, far exceeding existing non-catalyst-based systems. Second, the reaction conditions are mild, operating entirely at room temperature and atmospheric pressure, eliminating the need for high-temperature, high-pressure equipment or corrosive etchants, reducing energy consumption by more than 40%, and producing no wastewater pollution (the washing liquid can be recycled to ethanol). Third, it exhibits excellent electrochemical performance. Under optimal conditions (24-hour assembly), the product specific capacitance reaches 315 F / g (1 A / g), and the capacity retention rate reaches 92.3% after 5000 cycles, comprehensively surpassing existing commercial mesoporous carbon and non-catalyst-based system products.

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The components of the embodiments of the present invention shown herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0040] Example 1 A method for preparing a multi-cavity mesoporous carbon nanosphere battery material MCS-1 includes the following steps: Step 1: Mixing the cosolvent and surfactant. In a 250 mL three-necked flask, add 28 mL of anhydrous ethanol and 72 mL of deionized water, and stir magnetically for 5 min to form a homogeneous cosolvent system. Then add 0.72 g of P123 and 0.28 g of F127, set the stirring speed to 500 rpm, and continue stirring at room temperature for 15 min until the surfactant is completely dissolved and the system is a transparent and homogeneous solution.

[0041] Step 2: Addition of monomers and porogens. Add 0.58 g of anhydrous phloroglucinol (PG) to the above transparent solution and stir at 500 rpm for 15 min until the PG is completely dissolved. Slowly add 2.1 mL of mesitylene (TMB) dropwise at a rate of 1 drop / second using a pipette. After the addition is complete, continue stirring for 18 min to ensure that the TMB is fully mixed with the system, forming a milky white suspension.

[0042] Step 3: Accurately add 265 μL of ethylenediamine monohydrate (EDAM) to the milky white suspension, and stir continuously at 500 rpm and room temperature for 12 h. During this period, the solution gradually turns into a yellow MCS suspension.

[0043] Step 4: Transfer the yellow suspension to a 50 mL centrifuge tube and centrifuge at 9000 rpm for 12 min, discarding the supernatant; wash the precipitate three times alternately with 20 mL of anhydrous ethanol and 20 mL of deionized water (centrifuging at 9000 rpm for 12 min after each wash) to remove residual reagents; transfer the washed precipitate to a freeze-drying bottle and freeze-dry at -60℃ and a vacuum degree ≤10 Pa for 12 h to obtain a pale yellow MCS powder.

[0044] Step 5: Place the pale yellow MCS powder in a quartz boat, put it into a tube furnace, and introduce high-purity nitrogen (purity ≥99.999%) as a protective gas (gas flow rate: 50 mL / min); raise the temperature from room temperature to 800℃ at a rate of 1℃ / min, and hold at the target temperature for 2.5 h; allow it to cool naturally to room temperature, and remove the black solid powder, which is the target material, denoted as MCS-1.

[0045] Example 2 A method for preparing a multi-cavity mesoporous carbon nanosphere battery material MCS-2 includes the following steps: Example 2 was prepared using the same process as Example 1, except that the reaction time of the micelle assembly system was changed. Specifically, the micelle assembly reaction time in the catalytic self-assembly stage (after adding EDAM) was adjusted to 18 hours. All other steps (reagent dosage, stirring speed, centrifugal drying conditions, calcination parameters, etc.) were identical to those in Example 1. The final product was designated MCS-2.

[0046] Example 3 A method for preparing a multi-cavity mesoporous carbon nanosphere battery material MCS-3 includes the following steps: The preparation process of Example 3 is exactly the same as that of Example 1, except that the reaction time of the micelle assembly system is changed. Specifically, the micelle assembly reaction time of the catalytic self-assembly reaction stage (after adding EDAM) is adjusted to 24h. The remaining steps (reagent dosage, stirring speed, centrifugal drying conditions, calcination parameters, etc.) are completely consistent with those of Example 1. The final product is denoted as MCS-3.

[0047] Example 4 A method for preparing a multi-cavity mesoporous carbon nanosphere battery material MCS-4 includes the following steps: The preparation process of Example 4 is exactly the same as that of Example 1, except that the reaction time of the micelle assembly system is changed. Specifically, the micelle assembly reaction time of the catalytic self-assembly reaction stage (after adding EDAM) is adjusted to 30h. The remaining steps (reagent dosage, stirring speed, centrifugal drying conditions, calcination parameters, etc.) are completely consistent with those of Example 1. The final product is denoted as MCS-4.

[0048] Example 5 A method for preparing a multi-cavity mesoporous carbon nanosphere battery material MCS-5 includes the following steps: The preparation process of Example 5 is exactly the same as that of Example 1, except that the reaction time of the micelle assembly system is changed. Specifically, the micelle assembly reaction time of the catalytic self-assembly reaction stage (after adding EDAM) is adjusted to 36h. The remaining steps (reagent dosage, stirring speed, centrifugal drying conditions, calcination parameters, etc.) are completely consistent with those of Example 1. The final product is denoted as MCS-5.

[0049] Example 6 A method for preparing a multi-cavity mesoporous carbon nanosphere battery material includes the following steps: The difference between Example 6 and Example 3 is as follows: In step one, 20 mL of anhydrous ethanol and 80 mL of deionized water were added to a 250 mL three-necked flask; then 0.7 g of P123 and 0.3 g of F127 were added, and the stirring speed was set to 400 rpm. The mixture was stirred continuously at room temperature for 20 min until the surfactant was completely dissolved.

[0050] In step two, add 0.5 g of anhydrous phloroglucinol (PG) to the above transparent solution and stir at 600 rpm for 10 min until the PG is completely dissolved. Then, slowly add 2 mL of mesitylene (TMB) dropwise at a rate of 2 drops / second using a pipette. After the addition is complete, continue stirring for 10 min to ensure that the TMB is fully mixed with the system.

[0051] In step three, 260 μL of ethylenediamine monohydrate (EDAM) is precisely added to the milky white suspension, while maintaining a rotation speed of 400 rpm.

[0052] In step four, centrifuge at 8000 rpm for 15 min and discard the supernatant; wash the precipitate four times alternately with 20 mL of anhydrous ethanol and 20 mL of deionized water (centrifuge at 8000 rpm for 15 min after each wash) to remove residual reagents; transfer the washed precipitate to a freeze-drying bottle and freeze-dry under vacuum for 18 h.

[0053] In step five, a protective gas (gas flow rate: 40 mL / min) is used to raise the temperature from room temperature to 700℃ at a rate of 3℃ / min, and then the temperature is maintained for 2 hours after reaching the target temperature.

[0054] Example 7 The difference between Example 7 and Example 3 is as follows: In step one, 30 mL of anhydrous ethanol and 70 mL of deionized water were added to a 250 mL three-necked flask; then 0.8 g of P123 and 0.2 g of F127 were added, and the stirring speed was set to 600 rpm. The mixture was stirred continuously at room temperature for 10 min until the surfactant was completely dissolved.

[0055] In step two, add 0.6 g of anhydrous phloroglucinol (PG) to the above transparent solution and stir at 400 rpm for 20 min until the PG is completely dissolved; slowly add 3 mL of mesitylene (TMB) dropwise, and continue stirring for 20 min after the addition is complete to ensure that the TMB is fully mixed with the system.

[0056] In step three, 270 μL of ethylenediamine monohydrate (EDAM) is precisely added to the milky white suspension, and the rotation speed is maintained at 600 rpm.

[0057] In step four, centrifuge at 10,000 rpm for 10 min and discard the supernatant; wash the precipitate 5 times alternately with 20 mL of anhydrous ethanol and 20 mL of deionized water (centrifuge at 10,000 rpm for 10 min after each wash) to remove residual reagents; transfer the washed precipitate to a freeze-drying bottle and freeze-dry under vacuum for 24 h.

[0058] In step five, a protective gas (gas flow rate: 60 mL / min) is used to raise the temperature from room temperature to 900℃ at a rate of 5℃ / min, and then the temperature is maintained for 3 hours after reaching the target temperature.

[0059] Example 8 The difference between Example 8 and Example 3 is that in step one, 25 mL of anhydrous ethanol and 75 mL of deionized water are added to a 250 mL three-necked flask; then 0.75 g of P123 and 0.25 g of F127 are added.

[0060] Comparative Example 1 Preparation of EDAM-free carbon nanospheres (CM) Following the preparation process of Example 1, the step of "adding 265 μL of ethylenediamine monohydrate (EDAM)" was omitted. Instead, the precursor solution (PG+TMB mixture) was directly stirred at 500 rpm for 24 h. The specifications, amounts, and preparation steps (cosolvent ratio, surfactant amount, centrifugation, drying, calcination conditions, etc.) of the other reagents were completely consistent with those of Example 1. The final product was denoted as CM.

[0061] Table 1. Performance comparison of the multi-cavity mesoporous carbon nanosphere battery materials prepared in Examples 1-5 and the carbon nanospheres without EDAM catalysis prepared in Comparative Example 1.

[0062] Table 1 compares the performance of the multi-cavity mesoporous carbon nanosphere battery materials prepared in Examples 1-5 with the carbon nanospheres without EDAM catalysis prepared in Comparative Example 1. The data shows that the multi-cavity mesoporous carbon nanospheres prepared by the present invention through EDAM-catalyzed self-assembly (Examples 1-5) are significantly superior to those of Comparative Example 1 without EDAM in terms of specific surface area, pore volume, multi-cavity structure ratio, specific capacitance, and cycle stability. In particular, the multi-cavity structure ratio is increased by more than 2 times, demonstrating the crucial role of EDAM in the construction of intermolecular hydrogen bonds and the formation of multi-cavity structures. In Examples 2-5, when the micelle assembly time was 24h (MCS-3), the product had the best specific surface area, pore volume, multi-cavity ratio, specific capacitance, and cycle stability. When the time was too short (12h, 18h, MCS-1, MCS-2), the intermolecular hydrogen bond formation was insufficient, and the micelle assembly was incomplete, resulting in a decrease in performance. When the time was too long (30h, 36h, MCS-4, MCS-5), some micelles agglomerated, the pore structure collapsed slightly, and the performance dropped slightly, proving that 24h is the optimal assembly time.

[0063] In summary, this invention presents a multi-cavity mesoporous carbon nanosphere battery material and its preparation method. Through the synergistic regulation of EDAM catalysis and precise assembly time, it solves the problems of poor micelle stability and low reproducibility in traditional soft template methods. The addition of EDAM effectively guides the formation of directional hydrogen bonds between molecules, making the micelle assembly process more ordered and stable. By simply controlling the reaction time to 12-36 h, products with a multi-cavity structure ratio as high as 65.3%-92.5% can be stably and reproducibly prepared, far exceeding the uncatalyzed system (Comparative Example 1, only 31.7%), achieving precise customization of the core microstructure of the material. The multi-cavity structure ratio of the prepared mesoporous carbon nanospheres can be stabilized at 92.5% through process optimization. This porous cavity structure, compared to traditional solid or single-channel mesoporous spheres, can provide a much larger specific surface area (up to 1215 m²). 2 ·g -1 It features abundant ion insertion / extraction active sites and a large total pore volume (up to 1.82 cm³). 3 ·g -1The EDAM-catalyzed multi-cavity structure, with its suitable mesopore size (15.8 nm), forms an interconnected hierarchical pore system. This not only ensures sufficient electrolyte wetting but also provides a shortcut for rapid sodium ion diffusion, effectively reducing ion transport resistance and laying the foundation for high-rate performance. The multi-cavity structure itself can better buffer the volume changes caused by sodium ion insertion / extraction during charge and discharge, acting as an internal buffer space, thus helping to maintain the structural integrity of the electrode material, which is key to achieving long cycle life. As a sodium-ion battery anode material, it exhibits a specific capacitance of 228-315 F / g (optimal value 315 F / g) at a current density of 1 A / g. This is directly attributed to its high specific surface area, the ample sodium ion storage space provided by the multi-cavity structure, and the optimized ion diffusion path. After 5000 charge-discharge cycles, the capacity retention of the material remains stable at a high level of 85.7% to 92.3% (optimal value 92.3%). This fully demonstrates that the multi-cavity structure formed by EDAM catalysis possesses extremely high mechanical and electrochemical stability, effectively suppressing structural collapse and capacity decay during long-term cycling. Compared with Comparative Example 1 (specific capacitance 186 F / g, capacity retention 78.3%) without EDAM catalysis and existing commercial mesoporous carbon materials, the material of this invention shows significant advantages in both capacity and cycle life, providing a high-performance, low-cost, and easy-to-prepare solution to the problems of low capacity and rapid degradation of sodium-ion battery anode materials, and has great potential for industrial application.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a multi-cavity mesoporous carbon nanosphere battery material, characterized in that, include: Mix the cosolvent and surfactant, stirring until dissolved; Add the carbon source monomer and stir until dissolved; Add the pore-forming agent and stir until a suspension is formed; Finally, a hydrogen bonding catalyst was added, and after the reaction was completed by stirring, the mixture was washed, freeze-dried, and carbonized to obtain a multi-cavity mesoporous carbon nanosphere battery material.

2. The method for preparing the multi-cavity mesoporous carbon nanosphere battery material according to claim 1, characterized in that, The co-solvent is prepared by mixing 20-30 mL of anhydrous ethanol with 70-80 mL of deionized water; The surfactant was prepared by compounding 0.7-0.8g of P123 and 0.2-0.3g of F127.

3. The method for preparing the multi-cavity mesoporous carbon nanosphere battery material according to claim 1, characterized in that, The carbon source monomer is anhydrous phloroglucinol; the porogen is mesitylene, and the addition rate of the porogen is 1-2 drops / second; the hydrogen bonding catalyst is ethylenediamine monohydrate.

4. The method for preparing the multi-cavity mesoporous carbon nanosphere battery material according to claim 1, characterized in that, The ratio of the amount of the cosolvent, surfactant, carbon source monomer, porogen and hydrogen bonding catalyst is (90-110) mL: (0.9-1.1) g: (0.5-0.6) g: (2-3) mL: (260-270) μL.

5. The method for preparing the multi-cavity mesoporous carbon nanosphere battery material according to claim 1, characterized in that, The stirring speed is 400-600 rpm; the stirring time is 10-20 min.

6. The method for preparing the multi-cavity mesoporous carbon nanosphere battery material according to claim 1, characterized in that, The conditions for the stirring reaction include: stirring at 400-600 rpm at room temperature for 12-36 hours.

7. The method for preparing the multi-cavity mesoporous carbon nanosphere battery material according to claim 1, characterized in that, The washing conditions include: centrifuging at 8000-10000 rpm for 10-15 min, discarding the supernatant, and then washing the precipitate 3-5 times alternately with anhydrous ethanol and deionized water. The freeze-drying conditions include: freeze-vacuum drying at -60℃ and a vacuum degree ≤10Pa for 12-24 h.

8. The method for preparing the multi-cavity mesoporous carbon nanosphere battery material according to claim 1, characterized in that, The carbonization conditions include: introducing high-purity nitrogen as a protective gas at a flow rate of 40-60 mL / min; heating from room temperature to 700-900℃ at a rate of 1-5℃ / min; and holding the temperature for carbonization for 2-3 hours.

9. A multi-cavity mesoporous carbon nanosphere battery material, characterized in that, The multi-cavity mesoporous carbon nanosphere battery material was prepared using the preparation method according to any one of claims 1 to 8; the specific surface area of ​​the multi-cavity mesoporous carbon nanosphere battery material is 98-1215 m². 2 ·g -1 The total pore volume is 1.45-1.82 cm³. 3 ·g -1 The average mesopore size is 14.1–15.8 nm; the multi-structure ratio is 65.3%–92.5%; the specific capacitance at a current density of 1 A / g is 228–315 F / g; and the capacity retention after 5000 cycles is 85.7%–92.3%.

10. The application of the multi-cavity mesoporous carbon nanosphere battery material prepared by the preparation method of any one of claims 1 to 8 in sodium-ion batteries.

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