Halogenated hexabenzoquinone and conjugated polymer modified graphite electrode material thereof and preparation method thereof
By composite modification of graphite materials with halogenated hexabenzo[a]colony and hexabenzo[a]colony-like conjugated polymers, the gaps between graphite particles are filled to form a flexible coating layer, which solves the problems of rapid capacity decay and poor cycle stability of graphite materials at high rates, and achieves a significant improvement in high-rate discharge capacity and cycle stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-17
- Publication Date
- 2026-03-27
AI Technical Summary
Graphite materials exhibit low ion transport rate and poor cycle stability during high-rate charge and discharge processes. Especially under high-rate conditions, this leads to severe electrode polarization, reduced discharge capacity, and easy structural damage. Furthermore, side reactions occur on the graphite surface in the electrolyte, forming an unstable solid electrolyte interface film, which affects battery life.
Graphite was modified by composite modification with halogenated hexabenzo[a] ...
It significantly improves the high-rate discharge capacity and cycle stability of graphite, increasing the discharge capacity by 30-60% at 5C, and the capacity retention rate at 5C/0.1C to 75-85%. After 1000 cycles, the capacity retention rate is 85-90%, solving the problems of rapid capacity decay and poor cycle stability of graphite materials at high rates.
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Figure CN121748293A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium-ion battery anode material technology, specifically to halogenated hexabenzo[a]chloro ... Background Technology
[0002] Graphite, with its unique layered crystal arrangement, high theoretical specific capacity, low cost, and good environmental compatibility, has become the most widely used anode material for lithium-ion batteries, and is widely used in many important fields such as consumer electronics, electric vehicles, and large-scale energy storage systems.
[0003] However, in practical applications, especially under high-rate charge-discharge scenarios, graphite materials exhibit several significant performance shortcomings: First, low ion transport rate—although the layered structure of graphite is conducive to the insertion and extraction of lithium ions, there are strong interactions between its layers, and the intrinsic electronic conductivity still has room for improvement; under high-rate operating conditions, the transport kinetics of ions within the graphite particles and between the electrode and electrolyte interface are slow, leading to significant electrode polarization, which in turn causes a sharp decrease in discharge capacity, thus limiting rate performance. Second, poor cycle stability—during high-rate charge-discharge, the expansion stress caused by the rapid insertion of lithium ions into the graphite layers easily induces problems such as graphite particle cracking and damage to the overall electrode structure; at the same time, the electrolyte is prone to continuous side reactions on the graphite surface, forming an unstable and excessively thick solid electrolyte interface film, which further hinders the effective transport of ions, thereby shortening the overall cycle life of the battery.
[0004] To improve the performance of graphite materials at high rates, existing technologies have explored various modification methods, such as: nano-sizing of graphite—while this method can increase the ion-accessible area by increasing the specific surface area of the material, nanoscale graphite particles are prone to agglomeration, which may reduce the conductivity continuity of the electrode. Moreover, its preparation process is complex and costly, which is not conducive to large-scale industrialization; surface coating modification using a single conductive material—such as coating graphite with carbon nanotubes, graphite, or a certain single polymer. Although this method can enhance conductivity to a certain extent, carbon nanotubes and graphite have poor dispersion in actual systems and weak interfacial bonding with the graphite matrix. The conductivity of a single polymer is usually limited, making it difficult to simultaneously achieve the dual goals of high ion transport rate and excellent structural stability; doping modification by introducing metal oxides—while some metal oxides help improve the structural stability of graphite, these oxides themselves have poor conductivity. If added in excess, it will lead to an increase in the overall resistance of the electrode, which will have a negative impact on rate performance. Summary of the Invention
[0005] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention provide a graphite electrode material modified by halo-hexabenzo[a]corundum and its conjugated polymer and a method for its preparation, which solves the problems of rapid capacity decay and poor cycle stability of graphite at high rates.
[0006] To achieve the above objectives, the present invention provides the following technical solution: The graphite electrode material modified by halo-hexabenzo[a]methyl ... Graphite matrix: 85~95%, halo-hexabenzo[a]methyl: 1~5%, hexabenzo[a]methyl conjugated polymer: 2~8%, the sum of the mass percentages of each component is 100%.
[0007] Preferably, the graphite-based material includes natural graphite, artificial graphite, and expanded graphite, with a particle size of 5-20 micrometers and a specific surface area of 1-10 m². 2 / g.
[0008] Preferably, the halogenated hexabenzo[a]colone includes bromo-hexabenzo[a]colone and iodo-hexabenzo[a]colone, with a purity greater than 98% and a particle size of 100-500 nanometers.
[0009] Preferably, the hexabenzo[a] ... 4 ~5×10 4 The glass transition temperature is 80~120℃.
[0010] The preparation method of graphite electrode materials modified by halo-hexabenzo[a]methyl ... S1: Add halohexabenzo[a]col to organic solvent A and disperse by ultrasonication to obtain halohexabenzo[a]col dispersion; S2: Add the hexabenzo[a]corona] conjugated polymer to organic solvent B and stir to obtain a polymer solution; S3: Add the graphite matrix to a high-speed mixer and stir. Then slowly add the halo-hexabenzo[a]methyl methacrylate dispersion prepared in S1, followed by slowly adding the polymer solution. After the addition is complete, heat and keep the temperature while stirring to obtain the composite modified slurry. S4: The composite modified slurry is placed in a vacuum drying oven to dry in order to remove organic solvents and obtain dry composite modified graphite powder. Then the powder is transferred to an argon-protected tube furnace, heated and held at that temperature. After the heat treatment is completed, it is cooled to room temperature and finally crushed and sieved to obtain composite modified graphite electrode material.
[0011] Preferably, the organic solvent A added to the halo-hexabenzo[a]ol in S1 includes tetrahydrofuran and chloroform; the halo-hexabenzo[a]ol dispersion in S1 is obtained by dispersing with an ultrasonic machine with an ultrasonic power of 300~500W for 30~60min.
[0012] Preferably, the organic solvent B added to the hexabenzocobala conjugated polymer in S2 includes N,N-dimethylformamide and toluene; the polymer solution in S2 is obtained by stirring at a stirring rate of 300~500 rpm and 60~80℃ for 2~4 h.
[0013] Preferably, the graphite-based S3 is added to a high-speed mixer and stirred at a speed of 1000~1500 rpm; after the halo-hexabenzo[a]methyl]argent dispersion in S3 is added dropwise, stirring is continued for 30~60 min; after the polymer solution in S3 is added dropwise, the temperature of the system is raised to 80~100℃ and stirred continuously for 1~2 h.
[0014] Preferably, in step S4, the composite modified slurry is dried in a vacuum drying oven at 60~80℃ and with a vacuum degree of less than -0.09Mpa for 8~12 hours.
[0015] Preferably, in step S4, the obtained composite modified graphite powder is heated to 200-300℃ at a heating rate of 5-10℃ / min and held at that temperature for 2-4 hours. Finally, after being restored to room temperature, it is pulverized and passed through a 200-300 mesh sieve.
[0016] The technical effects and advantages of the present invention regarding the modified graphite electrode material and its preparation method of halo-hexabenzo[a]methyl ... 1. This invention is the first to combine halogenated hexabenzo[a]col with hexabenzo[a]col conjugated polymers to form a synergistic modification system of small molecule conjugated conductive agent and high molecule conjugated coating agent. Halogenated hexabenzo[a]col can fill the gaps between graphite particles and improve interfacial conductivity, while hexabenzo[a]col conjugated polymer can form a flexible coating layer on the graphite surface, construct a continuous conductive network and buffer structural expansion. The synergistic effect of the two makes up for the performance shortcomings of single modified materials.
[0017] 2. In this invention, the halogen atoms in the hexabenzo[a]halogenated hexabenzo[a]olium molecule are conjugated with hexabenzo[a]olium-like polymers. The weak interaction formed by the bond enhances the interfacial bonding between the two and graphite, while promoting the rapid migration of ions inside the electrode. This not only improves the high-rate discharge capacity of graphite, but also inhibits electrolyte decomposition, stabilizes the SEI film, and achieves simultaneous improvement in rate performance and cycle stability.
[0018] 3. This invention significantly improves the discharge capacity and capacity retention of the composite modified graphite electrode material at high rates: compared to unmodified graphite, its discharge capacity at 5C rate is increased by 30-50%, and its discharge capacity at 10C rate is increased by 40-60%. Moreover, the capacity retention at 5C / 0.1C rate is increased from 40-50% for unmodified graphite to 75-85%. This is because: the halogenated hexabenzo[a]corpores fills the gaps between graphite particles, reducing the contact resistance between particles and improving the interfacial conductivity; the continuous conductive network formed by the hexabenzo[a]corpores-like conjugated polymer accelerates the transport of electrons inside the electrode, while the flexible coating layer does not hinder ion insertion / extraction, significantly reducing polarization at high rates.
[0019] 4. After 1000 cycles at 1C, the capacity retention rate of the composite modified graphite electrode material is 85-90%, which is much higher than that of unmodified graphite. This is because the flexible coating layer of the hexabenzocorticoid conjugated polymer can buffer the interlayer expansion stress during the charging and discharging process of graphite and inhibit the cracking of graphite particles. At the same time, the coating layer can reduce the direct contact between the electrolyte and the graphite surface, inhibit the excessive growth and shedding of the SEI film, and ensure the stability of the ion transport channel.
[0020] 5. In this invention, the preferred mass percentage of the halo-hexabenzo[a]carbamate is 2-3%. If the percentage is too low, it cannot fully fill the gaps between graphite particles, and the improvement in interfacial conductivity is limited. If the percentage is too high, it is easy to cause particle agglomeration, which will hinder ion transport.
[0021] 6. In this invention, the preferred mass percentage of the hexabenzocobala conjugated polymer is 4-5%. If the percentage is too low, a continuous coating layer cannot be formed, resulting in insufficient structural stability. If the percentage is too high, the coating layer will be too thick, which will increase the resistance to ion intercalation and reduce the rate performance.
[0022] 7. In this invention, the heat treatment temperature is preferably 250~280℃: when the temperature is too low, the interfacial bonding force between the polymer and graphite is weak and it is easy to fall off; when the temperature is too high, the polymer may undergo thermal decomposition, damaging the conductive network.
[0023] 8. The invention utilizes the synergistic mechanism of halo-hexabenzo[a]cobalamin and hexabenzo[a]cobalamin-like conjugated polymers. When the two are combined, the halo-hexabenzo[a]cobalamin fills the gaps in the graphite to improve the interfacial conductivity, and the polymer forms a flexible coating layer to stabilize the structure and construct a continuous conductive network, thereby jointly improving the technical effect of graphite rate performance. Attached Figure Description
[0024] Figure 1 This is a flowchart of the process for preparing the halo-hexabenzo[a]coral and its conjugated polymer-modified graphite electrode material proposed in this invention. Detailed Implementation
[0025] 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.
[0026] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0027] Example 1 This embodiment provides a graphite electrode material modified with halo-hexabenzo[a]methyl ... Experimental materials: 90% natural graphite, 2% brominated hexabenzo[a]methyl ...
[0028] Experimental objective: Modified graphite electrode materials were prepared using natural graphite, brominated hexabenzo[a] ...
[0029] Experimental steps: S1: Add bromohexabenzo[a]bromo ... S2: The dibromo-substituted hexabenzo-3-hexylthiophene copolymer was added to N,N-dimethylformamide at a concentration of 8 mg / mL and stirred at 400 rpm for 3 h at 70 °C to obtain a polymer solution. S3: Add natural graphite to a high-speed mixer and stir at 1000 rpm. Then slowly add the bromohexabenzo[a]bromo ... S4: The composite modified slurry is placed in a vacuum drying oven and dried at 70°C and a vacuum degree of less than -0.10MPa for 10 hours to remove organic solvents and obtain dried composite modified graphite powder. Then, the powder is transferred to a tube furnace under argon protection and heated to 250°C at a heating rate of 8°C / min and held for 3 hours. After the heat treatment is completed, it is cooled to room temperature, and finally crushed and passed through a 200~300 mesh sieve to obtain composite modified graphite electrode material.
[0030] Experimental results: See Table 1 for details.
[0031] This embodiment uses natural graphite, brominated hexabenzo[a]col] and dibromosubstituted hexabenzo[a]col-3-hexylthiophene copolymer as raw materials. A composite modified slurry is prepared by ultrasonic dispersion and solution mixing. After vacuum drying at 70°C for 10 hours, the final material is obtained by argon heat treatment at 250°C. The test results show that its 0.1C discharge capacity is 368 mAh / g, the 5C discharge capacity is 302 mAh / g, the 5C / 0.1C capacity retention rate is 82.10%, and the capacity retention rate is 88.50% after 1000 cycles at 1C. This indicates that the composite system can significantly improve the rate performance and cycle stability of graphite.
[0032] Example 2 This embodiment provides a graphite electrode material modified with halo-hexabenzo[a]methyl ... Experimental materials: The composition consists of 92% artificial graphite, 2.5% iodobenzoquinone, and 5.5% dibromosubstituted hexabenzoquinone-furan copolymer.
[0033] Experimental objective: Modified graphite electrode materials were prepared using artificial graphite, iodobenzoquinone, and dibromosubstituted hexabenzoquinone-furan copolymer.
[0034] Experimental steps: S1: Iodobenzo[a]methyl iodide was added to chloroform with a concentration of 1.5 mg / mL and ultrasonically dispersed at 350 W for 35 min to obtain an iodobenzo[a]methyl iodide dispersion. S2: The dibromo-substituted hexabenzofuran copolymer was added to toluene with a concentration of 7 mg / mL and stirred at 350 rpm at 70 °C for 3 h to obtain a polymer solution; S3: Add artificial graphite to a high-speed mixer and stir at 1200 rpm. Then slowly add the iodohexabenzo[a]iodide dispersion prepared in S1. After the addition is complete, continue stirring for 50 min. Then slowly add the polymer solution. After the addition is complete, raise the temperature to 85℃ and keep stirring for 1.2 hours to obtain the composite modified slurry. S4: The composite modified slurry is placed in a vacuum drying oven and dried at 65°C and a vacuum degree of less than -0.095MPa for 9 hours to remove organic solvents and obtain dried composite modified graphite powder. Then, the powder is transferred to a tube furnace under nitrogen protection and heated to 270°C at a heating rate of 7°C / min and held at that temperature for 2.5 hours. After the heat treatment is completed, it is cooled to room temperature, and finally pulverized and passed through a 200~300 mesh sieve to obtain composite modified graphite electrode material.
[0035] Experimental results: See Table 2 for details.
[0036] This embodiment uses artificial graphite, iodo-hexabenzo[a]methyl methacrylate (IoD) and dibromo-substituted hexabenzo[a]methyl methacrylate-furan copolymer, which are dispersed and dissolved in chloroform and toluene solvents respectively, mixed with graphite and stirred at 85°C. Finally, the electrode material is obtained by vacuum drying at 65°C and nitrogen heat treatment at 270°C. Its 0.1C discharge capacity is 370 mAh / g, 5C discharge capacity is 308 mAh / g, capacity retention is 83.20%, and capacity retention reaches 89.20% after 1000 cycles, showing excellent performance comparable to that of Example 1.
[0037] Example 3 This embodiment provides a graphite electrode material modified with halo-hexabenzo[a]methyl ... Experimental materials: Expanded graphite 88%, brominated hexabenzo[a] ...
[0038] Experimental objective: Modified graphite electrode materials were prepared using expanded graphite, iodohexabenzo[a]methyl ... Experimental steps: S1: Bromohexabenzo[a] and iodohexabenzo[a] were added to a solvent of 0.8 mg / mL tetrahydrofuran-chloroform (volume ratio 1:1) and ultrasonically dispersed at 450W for 50 min to obtain a halohexabenzo[a] dispersion. S2: The dibromo-substituted hexabenzo-3-hexylthiophene-furan terpolymer was added to N,N-dimethylformamide-dimethyl sulfoxide (volume ratio 2:1) at a concentration of 9 mg / mL and stirred at 450 rpm at 65 °C for 3.5 h to obtain a polymer solution. S3: Expanded graphite is added to a high-speed mixer and stirred at 1400 rpm. Then, the halo-hexabenzo[a]col] dispersion prepared in S1 is slowly added dropwise. After the addition is completed, stirring is continued for 55 min. Then, the polymer solution is slowly added dropwise. After the addition is completed, the temperature is raised to 95℃ and stirred continuously for 1.8 hours to obtain the composite modified slurry. S4: The composite modified slurry was placed in a vacuum drying oven and dried at 75°C and a vacuum degree of less than -0.098MPa for 11 hours to remove organic solvents and obtain dried composite modified graphite powder. The powder was then transferred to a tube furnace protected by argon-nitrogen (volume ratio 1:1) and heated to 260°C at a heating rate of 9°C / min and held for 3.5 hours. After the heat treatment was completed, the powder was cooled to room temperature, pulverized and passed through a 200~300 mesh sieve to obtain composite modified graphite electrode material.
[0039] Experimental results: See Table 3 for details.
[0040] This embodiment uses expanded graphite, brominated hexabenzo[a] ...
[0041] Comparative Example 1 This embodiment provides a graphite electrode material modified with halo-hexabenzo[a]methyl ... Experimental materials: 100% natural graphite.
[0042] Experimental objective: Preparation of unmodified natural graphite electrode materials.
[0043] Experimental steps: S1: Unmodified natural graphite was placed in a vacuum drying oven and dried at 70°C and a vacuum degree of less than -0.10MPa for 10 hours to obtain dried unmodified natural graphite powder. The powder was then transferred to a tube furnace under argon protection and heated to 250°C at a heating rate of 8°C / min and held for 3 hours. After the heat treatment was completed, the powder was cooled to room temperature, pulverized, and passed through a 200~300 mesh sieve to obtain composite modified graphite electrode material.
[0044] Experimental results: See Table 4 for details.
[0045] This comparative example uses pure natural graphite that is directly dried and heat-treated without any modification. The results show that its 0.1C discharge capacity is 362 mAh / g, and its 5C discharge capacity is only 145 mAh / g, with a capacity retention rate as low as 40.10%. Moreover, after 1000 cycles, the capacity retention rate is only 56.20%, which is significantly lower than all other examples. This indicates that the performance of unmodified graphite is seriously insufficient under high rate and long cycle conditions.
[0046] Comparative Example 2 This embodiment provides a graphite electrode material modified with halo-hexabenzo[a]methyl ... Experimental materials: 90% natural graphite, 2% bromo-hexabenzo[a]methyl.
[0047] Experimental objective: Modified graphite electrode materials were prepared using natural graphite and iodohexabenzo[a]methyl ...
[0048] Experimental steps: S1: Add bromohexabenzo[a]bromo ... S2: Add natural graphite to a high-speed mixer and stir at 1000 rpm. Then slowly add the bromohexabenzo[a]bromo ... S4: The composite modified slurry is placed in a vacuum drying oven and dried at 70°C and a vacuum degree of less than -0.10MPa for 10 hours to remove organic solvents and obtain dried composite modified graphite powder. Then, the powder is transferred to a tube furnace under argon protection and heated to 250°C at a heating rate of 8°C / min and held for 3 hours. After the heat treatment is completed, it is cooled to room temperature, and finally crushed and passed through a 200~300 mesh sieve to obtain composite modified graphite electrode material.
[0049] Experimental results: See Table 5 for details.
[0050] This comparative example only used hexabenzobromobenzoic acid (HBA) and natural graphite for modification; the test results showed that its 0.1C discharge capacity was 360 mAh / g, its 5C discharge capacity was 202 mAh / g, its capacity retention rate was 56.10%, and its capacity retention rate after 1000 cycles was 68.50%. Although it was better than pure graphite, it was still much lower than the example, indicating that the effect of single hexabenzobromobenzoic acid modification was limited.
[0051] Comparative Example 3 This embodiment provides a graphite electrode material modified with halo-hexabenzo[a]methyl ... Experimental materials: 95% natural graphite, 5% dibromosubstituted hexabenzo-3-hexylthiophene copolymer.
[0052] Experimental objective: Modified graphite electrode materials were prepared using natural graphite and a dibromo-substituted hexabenzo-3-hexylthiophene copolymer.
[0053] Experimental steps: S1: The dibromo-substituted hexabenzo-3-hexylthiophene copolymer was added to N,N-dimethylformamide at a concentration of 8 mg / mL and stirred at 400 rpm for 3 h at 70 °C to obtain a polymer solution. S2: Add natural graphite to a high-speed mixer and stir at 1000 rpm. Then slowly add polymer solution. After the addition is complete, heat to 90°C and continue stirring for 1.5 hours to obtain composite modified slurry. S3: The composite modified slurry is placed in a vacuum drying oven and dried at 70°C and a vacuum degree of less than -0.10MPa for 10 hours to remove organic solvents and obtain dried composite modified graphite powder. Then, the powder is transferred to a tube furnace under argon protection and heated to 250°C at a heating rate of 8°C / min and held for 3 hours. After the heat treatment is completed, it is cooled to room temperature, and finally crushed and passed through a 200~300 mesh sieve to obtain composite modified graphite electrode material.
[0054] Experimental results: See Table 6 for details.
[0055] This comparative example only used dibromo-substituted hexabenzo-3-hexylthiophene copolymer modified with natural graphite; the material had a discharge capacity of 363 mAh / g at 0.1C, a discharge capacity of 225 mAh / g at 5C, a capacity retention of 62.00%, and a capacity retention of 75.30% after 1000 cycles. The performance was better than that of comparative example 2, but still not as good as the example, indicating that single polymer coating cannot achieve a synergistic enhancement effect.
[0056] Comparative Example 4 This embodiment provides a graphite electrode material modified with halo-hexabenzo[a]methyl ... Experimental materials: The copolymer contains 85% natural graphite, 8% brominated hexabenzo[a]methyl ...
[0057] Experimental objective: Modified graphite electrode materials were prepared using natural graphite, dibromo-substituted hexabenzo[3-hexylthiophene] copolymer, and excess hexabenzo[3-bromo] ...
[0058] Experimental steps: S1: Add bromohexabenzo[a]bromo ... S2: The dibromo-substituted hexabenzo-3-hexylthiophene copolymer was added to N,N-dimethylformamide at a concentration of 8 mg / mL and stirred at 400 rpm for 3 h at 70 °C to obtain a polymer solution. S3: Add natural graphite to a high-speed mixer and stir at 1000 rpm. Then slowly add the bromohexabenzo[a]bromo ... S4: The composite modified slurry is placed in a vacuum drying oven and dried at 70°C and a vacuum degree of less than -0.10MPa for 10 hours to remove organic solvents and obtain dried composite modified graphite powder. Then, the powder is transferred to a tube furnace under argon protection and heated to 250°C at a heating rate of 8°C / min and held for 3 hours. After the heat treatment is completed, it is cooled to room temperature, and finally crushed and passed through a 200~300 mesh sieve to obtain composite modified graphite electrode material.
[0059] Experimental results: See Table 7 for details.
[0060] In this comparative example, the amount of bromo-hexabenzo[a]methyl ...
[0061] Comparative Example 5 This embodiment provides a graphite electrode material modified with halo-hexabenzo[a]methyl ... Experimental materials: The copolymer consists of 80% natural graphite, 3% brominated hexabenzo[a]methyl ...
[0062] Experimental objective: Modified graphite electrode materials were prepared using natural graphite, excess dibromo-substituted hexabenzo-3-hexylthiophene copolymer, and brominated hexabenzo.
[0063] Experimental steps: S1: Add bromohexabenzo[a]bromo ... S2: The dibromo-substituted hexabenzo-3-hexylthiophene copolymer was added to N,N-dimethylformamide at a concentration of 8 mg / mL and stirred at 400 rpm for 3 h at 70 °C to obtain a polymer solution. S3: Add natural graphite to a high-speed mixer and stir at 1000 rpm. Then slowly add the bromohexabenzo[a]bromo ... S4: The composite modified slurry is placed in a vacuum drying oven and dried at 70°C and a vacuum degree of less than -0.10MPa for 10 hours to remove organic solvents and obtain dried composite modified graphite powder. Then, the powder is transferred to a tube furnace under argon protection and heated to 250°C at a heating rate of 8°C / min and held for 3 hours. After the heat treatment is completed, it is cooled to room temperature, and finally crushed and passed through a 200~300 mesh sieve to obtain composite modified graphite electrode material.
[0064] Experimental results: See Table 8 for details.
[0065] In this comparative example, the amount of polymer added was too high, and it was compounded with natural graphite and bromohexabenzo[a]methyl ...
[0066] Example 1 achieves an optimal balance in the ratio of natural graphite matrix, small molecule brominated hexabenzo[a]methyl ...
[0067] Example 2 uses a different system of artificial graphite matrix and iodohexabenzo[a]-furan copolymer, but its 0.1C capacity, rate retention and cycle retention are comparable to those of Example 1, which strongly demonstrates the universality and tunability of the modification strategy of the present invention for different types of graphite and different combinations of halogens and conjugated units, and broadens the range of material selection.
[0068] Example 3 uses expanded graphite mixed with brominated and iodinated hexabenzo[a]cort, and combined with a terpolymer. The process uses mixed solvents and mixed protective atmospheres. Its performance is at the same excellent level as that of Examples 1 and 2, which further verifies the good adaptability and process flexibility of the composite modification system to porous / special structure graphite matrices such as expanded graphite. It shows that the technology can be effectively optimized for graphite raw materials with different morphologies.
[0069] Comparative Example 1, used as a blank control, showed extremely low 5C discharge capacity and 1000-cycle capacity retention. This directly exposed the inherent defects of unmodified graphite, such as slow ion diffusion kinetics at high rates, numerous interfacial side reactions during long cycles, and easy structural damage, highlighting the absolute necessity of surface / structural modification.
[0070] The results of Comparative Example 2, which only added hexabenzobromobenzoic acid, show that while single halogenated small molecule modification provides some improvement, its effect is limited. Its capacity retention and cycling retention are far inferior to those of the examples, indicating that although small molecule modification can partially optimize the interface, it cannot form a durable mechanical support and a continuous conductive network, making it difficult to effectively resist the structural stress caused by long-term cycling.
[0071] While the single polymer coating in Comparative Example 3 provides some structural support, it may increase ion migration resistance, resulting in limited rate performance improvement. This indicates that without lead interface optimization using halogenated small molecules, the polymer may not bond tightly or uniformly with the graphite substrate, affecting the overall ion transport efficiency.
[0072] Comparative Examples 4 and 5 together reveal the critical importance of precise control of component ratios. In Comparative Example 4, excessive small molecules may cause local aggregation on the graphite surface, blocking ion channels and potentially increasing interfacial impedance due to their insulating properties, resulting in a decrease in overall capacity and failure to achieve optimal performance. In Comparative Example 5, excessive polymers may form an excessively thick and dense coating layer, severely hindering lithium-ion insertion / extraction kinetics, leading to significant degradation in both rate performance and capacity. These two comparative examples strongly demonstrate that the specific ratio range selected in the embodiments of this invention is an optimized range for achieving synergistic enhancement rather than mutual constraint.
[0073] The success of Examples 1-3 stands in stark contrast to the shortcomings of Comparative Examples 1-5, collectively and comprehensively demonstrating that only by employing the composite modification system of halohexabenzo[a]corona] and specific conjugated polymers proposed in this invention, in a specific ratio, and supplemented by corresponding preparation processes, can the key bottlenecks of graphite materials in high-rate and long-cycle scenarios be synergistically resolved, achieving a simultaneous and significant improvement in electronic conductivity, ion diffusion, and structural stability.
[0074] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.
[0075] In conclusion, 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 graphite electrode material modified with halo-hexabenzo[a]corona] and its conjugated polymers, characterized in that, Specifically, it includes the following components: Graphite matrix: 85~95%, halo-hexabenzo[a]methyl: 1~5%, hexabenzo[a]methyl conjugated polymer: 2~8%, the sum of the mass percentages of each component is 100%.
2. The halo-hexabenzo[a]methyl methacrylate and its conjugated polymer modified graphite electrode material as described in claim 1, characterized in that, Graphite-based materials include natural graphite, artificial graphite, and expanded graphite, with particle sizes ranging from 5 to 20 micrometers and specific surface areas ranging from 1 to 10 m². 2 / g.
3. The halo-hexabenzo[a]methyl methacrylate and its conjugated polymer modified graphite electrode material as described in claim 1, characterized in that, Halogenated hexabenzo[a]colone includes bromo-hexabenzo[a]colone and iodo-hexabenzo[a]colone, with a purity greater than 98% and a particle size of 100~500 nanometers.
4. The halo-hexabenzo[a]methyl methacrylate and its conjugated polymer modified graphite electrode material as described in claim 1, characterized in that, Hexabenzo[a]methyl conjugated polymers include copolymers of dibromo-substituted hexabenzo[a]methyl with thiophene monomers and copolymers of dibromo-substituted hexabenzo[a]methyl with furan monomers, with a number average molecular weight of 1 × 10⁻⁶. 4 ~5×10 4 The glass transition temperature is 80~120℃.
5. A method for preparing graphite electrode materials modified with halo-hexabenzo[a]methyl methacrylate and its conjugated polymers, characterized in that, Includes the following steps: S1: Add halohexabenzo[a]col to organic solvent A and disperse by ultrasonication to obtain halohexabenzo[a]col dispersion; S2: Add the hexabenzo[a]corona] conjugated polymer to organic solvent B and stir to obtain a polymer solution; S3: Add the graphite matrix to a high-speed mixer and stir. Then slowly add the halo-hexabenzo[a]methyl methacrylate dispersion prepared in S1, followed by slowly adding the polymer solution. After the addition is complete, heat and keep the temperature while stirring to obtain the composite modified slurry. S4: The composite modified slurry is placed in a vacuum drying oven to dry in order to remove organic solvents and obtain dry composite modified graphite powder. Then the powder is transferred to an argon-protected tube furnace, heated and held at that temperature. After the heat treatment is completed, it is cooled to room temperature and finally crushed and sieved to obtain composite modified graphite electrode material.
6. The method for preparing the halo-hexabenzo[a]methyl methacrylate and its conjugated polymer modified graphite electrode material as described in claim 5, characterized in that, In S1, the organic solvent A to which the halo-hexabenzo[a]col is added includes tetrahydrofuran and chloroform; the halo-hexabenzo[a]col dispersion in S1 is obtained by dispersing in an ultrasonic machine with an ultrasonic power of 300~500W for 30~60min.
7. The method for preparing the halo-hexabenzo[a]methyl methacrylate and its conjugated polymer modified graphite electrode material as described in claim 5, characterized in that, The organic solvent B added to the hexabenzocobala conjugated polymer in S2 includes N,N-dimethylformamide and toluene; the polymer solution in S2 is obtained by stirring at a stirring rate of 300~500 rpm and 60~80℃ for 2~4 h.
8. The method for preparing the halo-hexabenzo[a]methyl methacrylate and its conjugated polymer modified graphite electrode material as described in claim 5, characterized in that, Add S3 graphite-based material to a high-speed mixer and stir at 1000-1500 rpm; after the halo-hexabenzo[a]methyl]argent dispersion in S3 is added dropwise, continue stirring for 30-60 min; after the polymer solution in S3 is added dropwise, raise the temperature of the system to 80-100℃ and continue stirring for 1-2 h.
9. The method for preparing the halo-hexabenzo[a]methyl methacrylate and its conjugated polymer modified graphite electrode material as described in claim 5, characterized in that, In S4, the composite modified slurry is dried in a vacuum drying oven at 60~80℃ and a vacuum degree of less than -0.09Mpa for 8~12 hours.
10. The method for preparing the halo-hexabenzo[a]methyl methacrylate and its conjugated polymer-modified graphite electrode material as described in claim 5, characterized in that, In step S4, the obtained composite modified graphite powder is heated to 200-300℃ at a heating rate of 5-10℃ / min and held at that temperature for 2-4 hours. Finally, it is restored to room temperature and then pulverized through a 200-300 mesh sieve.