Preparation method of organic peroxide compound modified and regulated asphalt-based hard carbon material
Patent Information
- Application Number
- CN202611228529.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-13
- Publication Date
- 2026-09-22
AI Technical Summary
[0004]针对目前沥青易发生类石墨化演变、碳结构难以调控、导致的首次效率低等技术问题，本发明提出一种有机过氧化合物改性调控沥青基硬碳材料的制备方法，通过氧化断裂与三维立体交联协同作用，打破沥青的结构遗传性，从而构建具有超高容量和高首次效率的钠离子电池硬炭负极材料
[0020]（1）本发明摒弃了传统的固-气多相氧化或简单的物理混合工艺，采用液相体系下的分子工程策略。利用有机过氧类化合物在溶剂介质中的强渗透性，使调控剂与沥青分子实现分子级别的充分接触。通过氧化断裂作用，从分子层面破坏了沥青前驱体中易导致石墨化演变共轭芳香结构，并构建了高度稳定的三维立体交联网络，有效抑制了高温碳化过程中的类石墨化堆叠。
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Figure CN122789375A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of sodium-ion battery anode materials, and particularly relates to an asphalt-based hard carbon material. Background Technology
[0002] With the development of global new energy storage technologies, sodium-ion batteries (SIBs) are considered one of the best alternatives to lithium-ion batteries in large-scale energy storage systems due to their abundant resources, low cost, and high safety. Hard carbon, with its large interlayer spacing and abundant closed pores, is currently a research hotspot for sodium-ion battery anode materials. Asphalt, as a high-carbon-yield, low-cost carbon-rich precursor, shows great industrialization potential in the preparation of hard carbon. However, the numerous conjugated aromatic sheets in asphalt molecules easily undergo directional alignment during high-temperature heat treatment, resulting in a graphitized ordered structure (i.e., "soft carbon" characteristics). This ordered stacking severely compresses the sodium-ion storage space, leading to low reversible capacity and difficulty meeting the requirements of high-energy-density batteries.
[0003] Currently, the main strategies for suppressing graphitization of asphalt are air oxidation and chemical crosslinking. For example, patent CN115259135A involves heat-treating asphalt in an air atmosphere to construct crosslinking bridges between molecules using oxygen atoms. This method is low-cost and easy to operate, but the reaction is a typical gas-solid multiphase reaction, and the oxidation is often limited to the surface of precursor particles, making it difficult to penetrate deep into the molecular interior for uniform control, resulting in the presence of graphitized microcrystals in the "core". Patent CN118062826A uses sulfur to co-melt and mix with asphalt, utilizing the free radical initiation characteristics of sulfur in a low-stability state to lock the asphalt structure, which can effectively suppress graphitization of asphalt and increase the microcrystal spacing of hard carbon. However, it also faces serious equipment wear and exhaust gas treatment problems, and if the introduction of sulfur is not properly controlled, it will produce too many surface defects, reducing the material's initial coulombic efficiency. Summary of the Invention
[0004] To address the current technical problems of asphalt's tendency to undergo graphitization-like evolution, difficulty in controlling carbon structure, and resulting low initial efficiency, this invention proposes a method for preparing asphalt-based hard carbon materials by modifying and controlling the use of organic peroxide compounds. Through the synergistic effect of oxidative fracture and three-dimensional crosslinking, the structural inheritance of asphalt is broken, thereby constructing a sodium-ion battery hard carbon anode material with ultra-high capacity and high initial efficiency.
[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:
[0006] A method for preparing an organic peroxide-modified and regulated pitch-based hard carbon material includes the following steps:
[0007] Liquid-phase controlled reaction: The asphalt precursor is dissolved in an organic solvent, and an organic peroxide compound is added as a structure regulator to carry out a liquid-phase oxidation reaction to obtain a modified asphalt solution.
[0008] Precursor recovery: Modified asphalt precursors with molecular engineering modifications are obtained through solvent recovery processes.
[0009] Gradient pre-oxidation treatment: The modified asphalt precursor is placed in an atmosphere furnace for gradient heating pre-oxidation to solidify the three-dimensional cross-linked network.
[0010] High-temperature carbonization: Under the protection of an inert atmosphere, the stabilized precursor is carbonized at high temperature to obtain pitch-based hard carbon materials.
[0011] Furthermore, the mass ratio of the asphalt precursor to the organic peroxide compound is 100:(5-50).
[0012] Furthermore, the organic peroxide compound is selected from at least one of peroxyformic acid, peracetic acid, m-chloroperoxybenzoic acid, and p-chloroperoxybenzoic acid.
[0013] Furthermore, the organic solvent is selected from any one or a combination of tetrahydrofuran, toluene, xylene, N-methylpyrrolidone.
[0014] Furthermore, the asphalt precursor is selected from at least one of petroleum asphalt, coal tar pitch, and coal tar, and its softening point is 40-280℃.
[0015] Furthermore, the temperature of the liquid-phase oxidation reaction is 40-90℃, and the reaction time is 4-12h.
[0016] Furthermore, the gradient pre-oxidation treatment is carried out in an air atmosphere, specifically: the temperature is increased to 180-220℃ at a heating rate of 2-6℃ / min and held for 1-5h, and then increased to 300-400℃ at the same rate and held for 2-6h.
[0017] Furthermore, the high-temperature carbonization is carried out in an inert gas atmosphere, with a carbonization temperature of 1000-1500℃, a heating rate of 2-6℃ / min, and a constant temperature holding time of 2-6h.
[0018] This invention also protects the organic peroxide-modified pitch-based hard carbon material prepared by the above method, and the application of the hard carbon material as a negative electrode material in sodium-ion batteries; when the hard carbon material is used as a negative electrode in sodium-ion batteries, the initial coulombic efficiency is 80-95% and the reversible capacity is 280-420 mAh / g.
[0019] The beneficial effects of this invention are:
[0020] (1) This invention abandons the traditional solid-gas multiphase oxidation or simple physical mixing process and adopts a molecular engineering strategy in a liquid phase system. By utilizing the strong permeability of organic peroxide compounds in the solvent medium, the regulator and asphalt molecules can achieve full contact at the molecular level. Through oxidative cleavage, the conjugated aromatic structure in the asphalt precursor that is prone to graphitization is destroyed at the molecular level, and a highly stable three-dimensional cross-linked network is constructed, which effectively inhibits graphitization-like stacking during the high-temperature carbonization process.
[0021] (2) By precisely introducing non-conjugated sp between aromatic layers 3 By using hybridized carbon atoms, this invention effectively modulates the interlayer spacing of hard carbon. This three-dimensional cross-linked framework induces a large number of uniformly distributed nanoscale closed pores during carbonization. These closed pores provide extremely abundant storage sites for sodium ions, significantly improving the material's sodium storage capacity.
[0022] (3) In this invention, the asphalt-based hard carbon anode material is used in sodium-ion battery anode materials, and the reversible capacity of the prepared anode material is significantly increased by 50-100 mAh / g, and the first coulombic efficiency is increased by 3-8%.
[0023] (4) The organic peroxide compound regulation pathway used in this invention has obvious environmental advantages: no harmful gas emissions and the solvent can be recycled. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 The image shown is an HRTEM image of the pitch-based hard carbon synthesized in Example 1 of this invention.
[0026] Figure 2 SEM image of the pitch-based hard carbon synthesized in Example 1 of this invention.
[0027] Figure 3 Electrochemical charge-discharge curve of the asphalt-based hard carbon prepared and synthesized in Example 1 of the present invention. Detailed Implementation
[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and 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.
[0029] Unless otherwise specified, the raw materials used in the following examples and comparative examples are all commercially available products; all electrochemical tests were conducted using sodium-ion coin cells with a voltage window of 0.01-2.5V.
[0030] Example 1
[0031] An organic peroxide-modified and regulated pitch-based hard carbon material is prepared by the following steps:
[0032] S1: Weigh 10.0g of petroleum asphalt into a three-necked flask and add 100mL of tetrahydrofuran to dissolve it completely. Under nitrogen protection, add 3.0g of m-chloroperoxybenzoic acid, turn on the reflux condenser, adjust the oil bath temperature to 65℃, and react with mechanical stirring at a constant temperature for 8 hours.
[0033] S2: After the reaction solution cooled to room temperature, the THF solvent was recovered by vacuum distillation. The resulting solid product was dried in a vacuum oven at 80°C for 12 hours, then ground and pulverized, and passed through a 400-mesh sieve to obtain the modified asphalt precursor.
[0034] S3: In an air atmosphere, heat to 280°C at a rate of 2°C / min and stabilize at the gradient for 2 hours.
[0035] S4: Under nitrogen protection, carbonization is carried out at 1300°C for 4 hours with a heating rate of 5°C / min to obtain asphalt-based hard carbon, such as... Figure 1 and 2 As shown.
[0036] S5: Mix the obtained hard carbon, conductive carbon black, and binder into a slurry at a mass ratio of 8:1:1. Perform coin cell half-cell testing within a 0.01-2.5V window. The initial coulombic efficiency is 89.2%, and the reversible capacity is 395mAh / g.
[0037] Example 2
[0038] An organic peroxide-modified and regulated pitch-based hard carbon material is prepared by the following steps:
[0039] S1: Weigh 40.0g of coal tar pitch into a three-necked flask and add 400mL of xylene to dissolve it completely. Under nitrogen protection, add 20g of peracetic acid solution, turn on the reflux condenser, adjust the oil bath temperature to 85℃, and react with mechanical stirring at a constant temperature for 6 hours.
[0040] S2: After the reaction solution cooled to room temperature, xylene solvent was recovered by vacuum distillation. The resulting solid product was dried in a vacuum oven at 80°C for 12 hours, then ground and pulverized, and passed through a 400-mesh sieve to obtain the modified asphalt precursor.
[0041] S3: In an air atmosphere, heat to 280°C at a rate of 3°C / min and stabilize at the gradient for 3 hours.
[0042] S4: Carbonize at 1200°C for 5 hours under nitrogen protection by increasing the temperature at 5°C / min.
[0043] S5: Mix the obtained hard carbon, conductive carbon black, and binder into a slurry at a mass ratio of 8:1:1. Perform coin half-cell tests within a 0.01-2.5V window. Figure 3 As shown, the initial coulombic efficiency was 89.3%, and the reversible capacity was 387 mAh / g.
[0044] Comparative Example 1
[0045] An organic peroxide-modified and regulated pitch-based hard carbon material is prepared by the following steps:
[0046] S1: Weigh 10.0g of petroleum asphalt into a three-necked flask and add 80mL of toluene to dissolve it completely. Under nitrogen protection, add 2.0g of benzoyl peroxide, turn on the reflux condenser, adjust the oil bath temperature to 90℃, and react with mechanical stirring at a constant temperature for 4 hours.
[0047] S2: After the reaction solution cooled to room temperature, the THF solvent was recovered by vacuum distillation. The resulting solid product was dried in a vacuum oven at 80°C for 12 hours, then ground and pulverized, and passed through a 400-mesh sieve to obtain the modified asphalt precursor.
[0048] S3: In an air atmosphere, the temperature is increased to 320°C at a rate of 2°C / min, and then stabilized for 2 hours.
[0049] S4: Carbonize at 1400°C for 4 hours under nitrogen protection by increasing the temperature at 2°C / min.
[0050] S5: Mix the obtained hard carbon, conductive carbon black, and binder into a slurry at a mass ratio of 8:1:1. Perform coin cell half-cell testing within a 0.01-2.5V window. The initial coulombic efficiency was 86.8%, and the reversible capacity was 340mAh / g.
[0051] Comparative Example 2
[0052] An organic peroxide-modified and regulated pitch-based hard carbon material is prepared by the following steps:
[0053] S1: Weigh 10.0g of petroleum asphalt into a three-necked flask and add 80mL of toluene to dissolve it completely. Under nitrogen protection, add 4.0g of benzoyl peroxide, turn on the reflux condenser, adjust the oil bath temperature to 90℃, and react with mechanical stirring at a constant temperature for 4 hours.
[0054] S2: After the reaction solution cooled to room temperature, the THF solvent was recovered by vacuum distillation. The resulting solid product was dried in a vacuum oven at 80°C for 12 hours, then ground and pulverized, and passed through a 400-mesh sieve to obtain the modified asphalt precursor.
[0055] S3: In an air atmosphere, the temperature is increased to 320°C at a rate of 2°C / min, and then stabilized for 2 hours.
[0056] S4: Carbonize at 1400°C for 4 hours under nitrogen protection by increasing the temperature at 2°C / min.
[0057] S5: Mix the obtained hard carbon, conductive carbon black, and binder into a slurry at a mass ratio of 8:1:1. Perform coin cell half-cell tests within a 0.01-2.5V window, obtaining an initial coulombic efficiency of 86.8% and a reversible capacity of 339mAh / g.
[0058] Table 1. Core electrochemical performance of each embodiment and comparative example
[0059]
[0060] As shown in Table 1, the peroxyacid-based organic peroxides used in this invention, through the synergistic effect of oxidative cleavage and free radical crosslinking, significantly outperform conventional peroxides that only exert a single crosslinking effect. Compared with the comparative example, the reversible capacity of the examples is increased by up to approximately 56 mAh / g, and the first coulombic efficiency is increased by up to approximately 3.5%.
[0061] Traditional diacid peroxides and alkyl peroxides can only generate free radicals through thermal decomposition, initiating cross-linking reactions between asphalt molecules. They cannot break the original aromatic conjugated π bonds of asphalt, thus failing to fundamentally weaken its structural inheritance. At high temperatures, it is still prone to graphitization-like stacking, resulting in a low number of closed pores and insufficient sodium storage sites, significantly hindering capacity and efficiency improvements. The peroxyacid regulator of this invention can simultaneously exert a dual effect of strong oxidation and cross-linking in the liquid phase system. It breaks the continuous conjugated framework through oxidative fracture, inhibiting graphitization; and it constructs a three-dimensional network through cross-linking, inducing the generation of abundant closed nanopores. This dual effect synergistically enhances the simultaneous and significant improvement in sodium storage capacity and initial coulombic efficiency of hard carbon materials.
[0062] Example 3
[0063] An organic peroxide-modified and regulated pitch-based hard carbon material is prepared by the following steps:
[0064] S1: Weigh 10.0g of coal tar pitch into a three-necked flask and add 120mL of toluene to dissolve it completely. Under nitrogen protection, add 0.5g of peroxyformic acid, turn on the reflux condenser, adjust the oil bath temperature to 40℃, and react with mechanical stirring at a constant temperature for 10h.
[0065] S2: After the reaction solution cooled to room temperature, the toluene solvent was recovered by vacuum distillation. The resulting solid product was dried in a vacuum oven at 80°C for 12 hours, then ground and pulverized, and passed through a 400-mesh sieve to obtain the modified asphalt precursor.
[0066] S3: In an air atmosphere, heat to 200℃ at 4℃ / min and hold for 3 hours, then heat to 320℃ at the same rate and hold for 4 hours to complete the gradient pre-oxidation.
[0067] S4: Under nitrogen protection, heat to 1000℃ at 6℃ / min and carbonize at a constant temperature for 3 hours.
[0068] S5: The obtained hard carbon, conductive carbon black and binder were mixed in a mass ratio of 8:1:1 to form a slurry. After coating, drying and slicing, the slurry was assembled into a coin cell and tested in a voltage window of 0.01-2.5V. The initial coulombic efficiency was 88.2% and the reversible capacity was 385mAh / g.
[0069] Example 4
[0070] An organic peroxide-modified and regulated pitch-based hard carbon material is prepared by the following steps:
[0071] S1: Weigh 10.0g of petroleum asphalt into a three-necked flask and add 150mL of N-methylpyrrolidone to dissolve it completely. Under nitrogen protection, add 5.0g of p-chloroperoxybenzoic acid, turn on the reflux condenser, adjust the oil bath temperature to 90℃, and react with mechanical stirring at a constant temperature for 4 hours.
[0072] S2: After the reaction solution cooled to room temperature, the N-methylpyrrolidone solvent was recovered by vacuum distillation. The resulting solid product was dried in a vacuum oven at 80°C for 12 hours, then ground and pulverized, and passed through a 400-mesh sieve to obtain the modified asphalt precursor.
[0073] S3: In an air atmosphere, heat to 220℃ at 6℃ / min and hold for 1 hour, then heat to 400℃ at the same rate and hold for 2 hours to complete the gradient pre-oxidation.
[0074] S4: Under nitrogen protection, heat to 1500℃ at 3℃ / min and carbonize at a constant temperature for 6 hours.
[0075] S5: The obtained hard carbon, conductive carbon black and binder were mixed in a mass ratio of 8:1:1 to form a slurry. After coating, drying and slicing, the slurry was assembled into a coin cell and tested in a voltage window of 0.01-2.5V. The initial coulombic efficiency was 91.5% and the reversible capacity was 388mAh / g.
[0076] Example 5
[0077] An organic peroxide-modified and regulated pitch-based hard carbon material is prepared by the following steps:
[0078] S1: Weigh 10.0g of coal tar pitch into a three-necked flask, add 100mL of a mixed solvent of tetrahydrofuran and xylene (volume ratio 1:1) and dissolve completely. Under nitrogen protection, add 2.5g of a mixture of peracetic acid and m-chloroperoxybenzoic acid (mass ratio 1:1), turn on reflux condenser, adjust the oil bath temperature to 60℃, and react with mechanical stirring at a constant temperature for 12h.
[0079] S2: After the reaction solution cools to room temperature, the mixed solvent is recovered by vacuum distillation. The resulting solid product is dried in a vacuum oven at 80°C for 12 hours, then ground and pulverized, and passed through a 400-mesh sieve to obtain the modified asphalt precursor.
[0080] S3: In an air atmosphere, heat to 180℃ at 2℃ / min and hold for 5 hours, then heat to 300℃ at the same rate and hold for 6 hours to complete the gradient pre-oxidation.
[0081] S4: Under nitrogen protection, heat to 1250℃ at a rate of 2℃ / min and carbonize at a constant temperature for 2 hours.
[0082] S5: The obtained hard carbon, conductive carbon black and binder were mixed in a mass ratio of 8:1:1 to form a slurry. After coating, drying and slicing, the slurry was assembled into a coin cell and tested in a voltage window of 0.01-2.5V. The initial coulombic efficiency was 88.6% and the reversible capacity was 398mAh / g.
[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing pitch-based hard carbon materials modified and regulated by organic peroxide compounds, characterized in that, Includes the following steps: S1: Dissolve the asphalt precursor in an organic solvent, add an organic peroxide compound, and carry out a liquid-phase oxidation reaction to obtain a modified asphalt precursor. S2: The modified asphalt precursor is subjected to gradient pre-oxidation and carbonization treatment to obtain the asphalt-based hard carbon material.
2. The method for preparing asphalt-based hard carbon materials modified and regulated by organic peroxide compounds according to claim 1, characterized in that, The mass ratio of the asphalt precursor to the organic peroxide compound is 100:(5-50).
3. The method for preparing asphalt-based hard carbon materials modified and regulated by organic peroxide compounds according to claim 2, characterized in that, The organic peroxide compound is selected from at least one of aliphatic peroxides, aromatic peroxides, diaryl peroxides, aliphatic diacyl peroxides, alkyl hydroperoxides, and dialkyl peroxides.
4. The method for preparing asphalt-based hard carbon materials modified and regulated by organic peroxide compounds according to claim 2, characterized in that, The organic peroxide compound is at least one of peroxyformic acid, peracetic acid, m-chloroperoxybenzoic acid, and p-chloroperoxybenzoic acid.
5. The method for preparing asphalt-based hard carbon materials modified and regulated by organic peroxide compounds according to claim 2, characterized in that, The organic solvent is selected from any one or a combination of tetrahydrofuran, toluene, xylene, and N-methylpyrrolidone.
6. The method for preparing organic peroxide-modified pitch-based hard carbon materials according to any one of claims 1-4, characterized in that, The asphalt precursor is selected from at least one of petroleum asphalt, coal tar pitch, coal tar, and combinations thereof, and the softening point of the asphalt precursor is 40-280℃.
7. The method for preparing organic peroxide-modified and regulated pitch-based hard carbon materials according to claim 5, characterized in that, The temperature of the liquid-phase oxidation reaction is 40-90℃, and the reaction time is 4-12 hours.
8. The method for preparing asphalt-based hard carbon materials modified and regulated by organic peroxide compounds according to claim 1, characterized in that, The specific steps of the gradient pre-oxidation are as follows: heat to 180-220℃ at a heating rate of 2-6℃ / min and hold for 1-5 hours, then heat to 300-400℃ at the same rate and hold for 2-6 hours.
9. The method for preparing organic peroxide-modified and regulated pitch-based hard carbon materials according to claim 1, characterized in that, The carbonization process is carried out in an inert gas atmosphere at a temperature of 1000-1500℃ for 2-6 hours, with a heating rate of 2-6℃ / min.
10. Organic peroxide-modified pitch-based hard carbon material prepared by the method of any one of claims 1-8.