Preparation method of anti-agglomeration high-conductivity graphene negative electrode material

Abstract

The invention discloses a preparation method of an anti-agglomeration high-conductivity graphene negative electrode material, and particularly relates to the technical field of graphene electrode materials. The preparation method comprises the following steps: dispersing graphene oxide in a polyvinyl alcohol aqueous solution by adopting an electrostatic spinning technology to prepare a graphene oxide / polyvinyl alcohol composite fiber membrane with a three-dimensional network structure; molybdenum tetracarbonyl steam is uniformly loaded on the surfaces and pores of the fibers through vapor deposition in nitrogen; argon and hydrogen are introduced, the selenium powder is heated to generate selenium steam, selenylation of the molybdenum precursor and reduction of graphene oxide are synchronously completed, and a Mo / graphene core-shell composite structure is formed; and finally, carrying out ball milling, screening, pulping, coating and drying to obtain the negative electrode material. According to the preparation method, a three-dimensional conductive skeleton is constructed through electrostatic spinning, meanwhile, the use threshold of equipment is lowered, atomic-scale dispersion, firm loading and dispersion uniformity of active substances are achieved in combination with vapor deposition and a synchronous selenylation reduction process, meanwhile, a core-shell structure is formed, and Mo in a product meets specific electrochemical requirements.

Description

Technical Field

[0001] This invention relates to the field of graphene electrode material technology, and to a method for preparing a graphene anode material with anti-agglomeration and high conductivity. Background Technology

[0002] Graphene, with its unique two-dimensional layered structure, excellent conductivity, high mechanical strength, and huge theoretical specific surface area, is considered a highly promising anode material for lithium-ion batteries. Its single-atom-layer thickness theoretically provides extremely high active site density and extremely short ion transport paths, contributing to high specific capacity and fast charge-discharge performance. Furthermore, graphene's high conductivity significantly improves the electron transport efficiency of the electrode, while its flexibility helps mitigate volume expansion during lithium-ion insertion / extraction, thereby improving cycle stability. Therefore, graphene and its composite materials demonstrate significant value in developing high-performance, long-life lithium-ion batteries and are considered one of the key directions for overcoming the performance bottlenecks of traditional carbon-based anode materials.

[0003] However, in actual preparation and application, the strong van der Waals forces between graphene sheets easily lead to irreversible aggregation or recombination, forming graphite microcrystals or multilayer graphite structures. This aggregation phenomenon severely weakens the inherent advantages of graphene: firstly, aggregation leads to a significant decrease in the effective specific surface area, reducing the active interfaces available for electrochemical reactions; secondly, the stacking of sheets makes the ion transport path tortuous and lengthy, significantly reducing ion diffusion kinetics; and thirdly, the discontinuous electron conduction path within the agglomerates increases the internal resistance of the electrode. These factors combined result in the actual capacity of graphene-based anode materials being far lower than the theoretical value, with poor rate performance and rapid capacity decay during cycling, severely restricting their practical application in high-performance batteries.

[0004] To suppress graphene aggregation, researchers have explored various strategies, such as surface functionalization, introducing spacers, and constructing three-dimensional porous networks. Common methods include combining graphene with nanoparticles, carbon nanotubes, or polymers to physically or chemically widen the interlayer spacing. However, these methods are often complex, costly, and prone to re-aggregation due to structural relaxation during long-term cycling. Furthermore, traditional mechanical mixing or liquid-phase composite methods struggle to achieve uniform loading and robust bonding of active materials on the graphene surface, easily leading to active material detachment and increased interfacial resistance. Therefore, developing a novel method that fundamentally suppresses graphene aggregation, achieves uniform dispersion and stable loading of active materials, and is suitable for large-scale preparation with controllable processes has become a key technological challenge driving the practical application of graphene anode materials. Summary of the Invention

[0005] To overcome the above-mentioned defects of the prior art, embodiments of the present invention provide a method for preparing anti-agglomeration highly conductive graphene anode materials, which solves the problem that graphene is prone to agglomeration due to strong van der Waals forces between sheets, resulting in a decrease in specific surface area, a reduction in active sites, and obstruction of electron / ion transport.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The preparation method of anti-agglomeration highly conductive graphene anode material specifically includes the following steps: S1: Graphene oxide is uniformly dispersed in a polyvinyl alcohol aqueous solution to form a spinnable precursor solution. The precursor solution is then spun using an electrospinning device, and a graphene oxide / polyvinyl alcohol composite fiber membrane with a three-dimensional interconnected network structure is collected on a receiving plate. S2: The prepared graphene oxide / polyvinyl alcohol composite fiber membrane is placed in a tube furnace and then circulated with... Tetracarbonyl molybdenum vapor, supported by a carrier, undergoes a vapor-phase deposition reaction in the reaction zone; S3: After the reaction in S2 is completed, the temperature is lowered to room temperature and solid selenium powder is placed upstream of the tube furnace. Then, an argon-hydrogen mixture is introduced, and the selenium powder is heated to generate selenium vapor. Finally, the composite fiber is heated to react with selenium. S4: After the reaction is complete and cooled to room temperature, the composite fiber membrane is ball-milled, and the particles are collected by sieving. Then, the short fiber powder, PVDF, and SP are mixed and added to N-methylpyrrolidone. Finally, the coating is evenly coated onto the copper foil current collector, dried in an oven and rolled, and then transferred to a vacuum drying oven to obtain the product with Mo... / Graphene core-shell structured graphene anode material with anti-agglomeration and high conductivity.

[0007] Preferably, in S1, graphene oxide is uniformly dispersed in a polyvinyl alcohol aqueous solution at a mass ratio of 1:5 to 10.

[0008] Preferably, in S1, the voltage of the electrospinning equipment is set to 15~25kV, the injection speed is 0.5~1.5mL / h, the receiving distance is 10~20cm, the relative humidity is less than 40±5%, and the ambient temperature is 25±3℃.

[0009] Preferably, in S2, molybdenum tetracarbonyl vapor is mixed into the carrier at a molar concentration of 0.5-2%. It is placed in the reaction zone at a flow rate of 100 sccm.

[0010] Preferably, in S2, the tube furnace is heated to 120~180℃ at a rate of 5℃ / min and the reaction is continued for 2 hours.

[0011] Preferably, in step S3, argon and hydrogen are uniformly mixed at a volume ratio of argon:hydrogen = 9:1.

[0012] Preferably, in step S3, the composite fibers are heated to 500~600℃ at a rate of 5℃ / min and reacted continuously for 2 hours.

[0013] Preferably, in step S4, the composite fibers obtained after the reaction are ball-milled at a speed of 200-300 rpm for 5 minutes to obtain short fiber powder, and the short fiber powder is sieved to collect particles with a D50 of 10-20 μm.

[0014] Preferably, in step S4, short fiber powder, PVDF, and SP are mixed in a mass ratio of 97-98.5:1.0-2:0.5-1, and then the mixture is dissolved in N-methylpyrrolidone to obtain a coating. The coating is then prepared with an areal density of 1.5-2.5 mg / L. The coating is evenly applied to the copper foil current collector, then dried in an oven at 80-85℃ and rolled, and finally dried in a vacuum drying oven at 120℃ for 12 hours.

[0015] Preferably, as described in S4 The graphene core-shell structure is The nanosheets are uniformly loaded onto the surface of graphene fibers to form a tightly bonded core-shell composite structure.

[0016] The technical effects and advantages of the method for preparing anti-agglomeration highly conductive graphene anode material of the present invention are as follows: 1. This invention first constructs a three-dimensional conductive framework and directly prepares a graphene oxide / polymer composite fiber membrane with a continuous network structure through electrospinning as a pre-dispersed and non-agglomerated support framework. Secondly, a chemical vapor deposition technique is used to uniformly penetrate and deposit a molybdenum source in the gas phase onto the surface and internal pores of the fiber network to achieve atomic-level dispersion of the precursor. Finally, a one-step heat treatment in a selenium vapor atmosphere is used to simultaneously complete the selenization of the molybdenum precursor and the reduction of graphene oxide, forming a firmly bonded core-shell structure.

[0017] 2. This invention achieves molecular-level and even atomic-level dispersion of the molybdenum precursor by uniformly infiltrating and depositing molybdenum tetracarbonyl in vapor form onto the surface and pores of a fiber network via chemical vapor deposition. Subsequently, the selenization of the molybdenum precursor and the thermal reduction of graphene oxide are completed in a single step in an argon-hydrogen mixed atmosphere. This simultaneous process promotes… Nanosheets are grown in situ and form a tightly bonded core-shell structure with the reduced graphene fibers. This strong interfacial bonding effectively prevents the loss of active materials during cycling, ensuring an efficient and stable electron / ion transport pathway.

[0018] 3. The invention prepares... The graphene core-shell structured anode material exhibits high initial discharge specific capacity, excellent cycle stability, and superior rate performance, while also having low electrode resistance. This indicates that the material has successfully solved the key problems of traditional graphene-based materials, such as rapid capacity decay, high internal resistance, and poor rate performance caused by agglomeration. This verifies the effectiveness and advancement of the preparation method in improving the overall performance of anode materials.

[0019] 4. This invention, resulting in In the core-shell structure of graphene, Nanosheets are chemically anchored firmly to the surface of graphene fibers, forming a tight interfacial contact between the two. This structure not only effectively suppresses the volume expansion and peeling of active materials during charging and discharging, but also establishes a continuous electron conduction channel and a shorter ion diffusion path. The strong coupling effect of the core-shell interface significantly reduces charge transfer impedance and improves the reaction kinetics of the material, thereby achieving a balance between high rate performance and long cycle life. Attached Figure Description

[0020] Figure 1 This is a flowchart of the method for preparing anti-agglomeration highly conductive graphene anode material proposed in this invention. Detailed Implementation

[0021] 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.

[0022] 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.

[0023] Example 1 This embodiment provides a method for preparing agglomeration-resistant, highly conductive graphene anode material, the specific implementation steps of which include: Experimental materials: Graphene oxide, polyvinyl alcohol aqueous solution, Tetracarbonyl molybdenum, selenium powder, PVDF, SP, NMP.

[0024] Experimental objective: Prepare a graphene anode material with high conductivity and anti-agglomeration properties.

[0025] Experimental steps: S1: Graphene oxide is uniformly dispersed in a polyvinyl alcohol aqueous solution at a mass ratio of 1:10 to form a spinnable precursor solution. Then, the precursor solution is spun using an electrospinning device at a voltage of 25kV, a feeding speed of 1.5mL / h, a receiving distance of 20cm, an ambient relative humidity of less than 40%, and a temperature of 25℃. The graphene oxide / polyvinyl alcohol composite fiber membrane with a three-dimensional interconnected network structure is collected on the receiving plate. S2: The prepared graphene oxide / polyvinyl alcohol composite fiber membrane is placed in a tube furnace and then circulated with... Molybdenum tetracarbonyl vapor with a carrier molar concentration of 2% was placed in the reaction zone at a flow rate of 100 sccm, and the reaction temperature was controlled at 180℃ for 2 hours. S3: After the reaction in S2 is completed, the temperature is lowered to room temperature and solid selenium powder is placed upstream of the tube furnace. Then, a mixed gas with an argon-hydrogen volume ratio of 9:1 is introduced, and the selenium powder is heated to generate selenium vapor. Finally, the composite fiber is heated to 650°C at a heating rate of 5°C / min and the reaction is continued for 2 hours. S4: After the reaction is complete and cooled to room temperature, the mixture is ball-milled at 200 rpm for 5 minutes to obtain short fibrous powder. Particles with a D50 particle size of 10 μm are collected by sieving. The short fibrous powder, PVDF, and SP are then mixed at a mass ratio of 98.5:1.0:0.5 and subsequently placed in N-methylpyrrolidone for further mixing. Finally, the coating is prepared with an areal density of 2.5 mg / L. The coating is evenly applied to the copper foil current collector, dried in an 80℃ oven and rolled, and then transferred to a 120℃ vacuum drying oven for 12 hours.

[0026] Experimental results: See Table 1 for details.

[0027] Table 1: Test Results of Example 1 This embodiment utilizes an innovative process—electrospinning-vapor phase infiltration-simultaneous selenization reduction—to prepare Mo with a unique structure, uniform dispersion, and excellent conductivity. / Graphene composite anode material. This material exhibits high specific capacity, excellent cycle stability, and outstanding rate performance in lithium-ion batteries, fundamentally solving the problem of graphene agglomeration with active materials, thus verifying the effectiveness and advancement of this invention.

[0028] Example 2 This embodiment provides a method for preparing agglomeration-resistant, highly conductive graphene anode material, the specific implementation steps of which include: Experimental materials: Graphene oxide, polyvinyl alcohol aqueous solution, Tetracarbonyl molybdenum, selenium powder, PVDF, acetylene black, NMP.

[0029] Experimental objective: The effect of replacing SP in the conductive agent with acetylene black on the performance of the negative electrode material was tested.

[0030] Experimental steps: S1: Graphene oxide is uniformly dispersed in a polyvinyl alcohol aqueous solution at a mass ratio of 1:10 to form a spinnable precursor solution. Then, the precursor solution is spun using an electrospinning device at a voltage of 25kV, a feeding speed of 1.5mL / h, a receiving distance of 20cm, an ambient relative humidity of less than 40%, and a temperature of 25℃. The graphene oxide / polyvinyl alcohol composite fiber membrane with a three-dimensional interconnected network structure is collected on the receiving plate. S2: The prepared graphene oxide / polyvinyl alcohol composite fiber membrane is placed in a tube furnace and then circulated with... Molybdenum tetracarbonyl vapor with a carrier molar concentration of 2% was placed in the reaction zone at a flow rate of 100 sccm, and the reaction temperature was controlled at 180℃ for 2 hours. S3: After the reaction in S2 is completed, the temperature is lowered to room temperature and solid selenium powder is placed upstream of the tube furnace. Then, a mixed gas with an argon-hydrogen volume ratio of 9:1 is introduced, and the selenium powder is heated to generate selenium vapor. Finally, the composite fiber is heated to 650°C at a heating rate of 5°C / min and the reaction is continued for 2 hours. S4: After the reaction is complete and cooled to room temperature, the mixture is ball-milled at 200 rpm for 5 minutes to obtain short fibrous powder. Particles with a D50 particle size of 10 μm are collected by sieving. The short fibrous powder, PVDF, and acetylene black are then mixed at a mass ratio of 98.5:1.0:0.5 and subsequently mixed in N-methylpyrrolidone. Finally, the coating is prepared with an areal density of 2.5 mg / L. The coating is evenly applied to the copper foil current collector, dried in an 80℃ oven and rolled, and then transferred to a 120℃ vacuum drying oven for 12 hours.

[0031] Experimental results: See Table 2 for details.

[0032] Table 2: Test Results of Example 2 This embodiment replaces the conductive agent SP with acetylene black, thus preparing a product while maintaining the same process route and core structure. The graphene core-shell structure anode material has a slightly higher overall electrode resistance due to the lower efficiency of acetylene black in building the conductive network in the electrode compared to SP. The initial discharge specific capacity, cycle retention rate, and rate performance are all slightly lower than in Example 1.

[0033] Example 3 This embodiment provides a method for preparing agglomeration-resistant, highly conductive graphene anode material, the specific implementation steps of which include: Experimental materials: Graphene oxide, polyvinyl alcohol aqueous solution, Tetracarbonyl molybdenum, selenium powder, PVDF, SP, NMP.

[0034] Experimental objective: Composite fiber membranes were prepared by reducing the voltage, injection speed, and receiving distance of the electrospinning equipment.

[0035] Experimental steps: S1: Graphene oxide is uniformly dispersed in a polyvinyl alcohol aqueous solution at a mass ratio of 1:10 to form a spinnable precursor solution. Then, the precursor solution is spun using an electrospinning device at a voltage of 15kV, a feeding speed of 0.5mL / h, a receiving distance of 10cm, an ambient relative humidity of less than 40%, and a temperature of 25℃. The graphene oxide / polyvinyl alcohol composite fiber membrane with a three-dimensional interconnected network structure is collected on the receiving plate. S2: The prepared graphene oxide / polyvinyl alcohol composite fiber membrane is placed in a tube furnace and then circulated with... Molybdenum tetracarbonyl vapor with a carrier molar concentration of 2% was placed in the reaction zone at a flow rate of 100 sccm, and the reaction temperature was controlled at 180℃ for 2 hours. S3: After the reaction in S2 is completed, the temperature is lowered to room temperature and solid selenium powder is placed upstream of the tube furnace. Then, a mixed gas with an argon-hydrogen volume ratio of 9:1 is introduced, and the selenium powder is heated to generate selenium vapor. Finally, the composite fiber is heated to 650°C at a heating rate of 5°C / min and the reaction is continued for 2 hours. S4: After the reaction is complete and cooled to room temperature, the mixture is ball-milled at 200 rpm for 5 minutes to obtain short fibrous powder. Particles with a D50 particle size of 10 μm are collected by sieving. The short fibrous powder, PVDF, and SP are then mixed at a mass ratio of 98.5:1.0:0.5 and subsequently placed in N-methylpyrrolidone for further mixing. Finally, the coating is prepared with an areal density of 2.5 mg / L. The coating is evenly applied to the copper foil current collector, dried in an 80℃ oven and rolled, and then transferred to a 120℃ vacuum drying oven for 12 hours.

[0036] Experimental results: See Table 3 for details.

[0037] Table 3: Test Results of Example 3 The reduction in electrospinning parameters resulted in a coarser composite fiber diameter and a decrease in the uniformity of the three-dimensional network, which affected the gas phase penetration and deposition uniformity of the molybdenum precursor. Consequently, the loading distribution of the active material MoSe2 on the graphene framework was not ideal, and the electron transport path was blocked. Therefore, the initial capacity, rate performance, and cycle stability of the material were all reduced compared to Example 1.

[0038] Example 4 This embodiment provides a method for preparing agglomeration-resistant, highly conductive graphene anode material, the specific implementation steps of which include: Experimental materials: Graphene oxide, polyvinyl alcohol aqueous solution, Tetracarbonyl molybdenum, selenium powder, PVDF, SP, NMP.

[0039] Experimental objective: Adjusting the tetracarbonyl molybdenum vapor in The molar concentration in.

[0040] Experimental steps: S1: Graphene oxide is uniformly dispersed in a polyvinyl alcohol aqueous solution at a mass ratio of 1:10 to form a spinnable precursor solution. Then, the precursor solution is spun using an electrospinning device at a voltage of 25kV, a feeding speed of 1.5mL / h, a receiving distance of 20cm, an ambient relative humidity of less than 40%, and a temperature of 25±3℃. The graphene oxide / polyvinyl alcohol composite fiber membrane with a three-dimensional interconnected network structure is collected on the receiving plate. S2: The prepared graphene oxide / polyvinyl alcohol composite fiber membrane is placed in a tube furnace and then circulated with... Molybdenum tetracarbonyl vapor with a carrier molar concentration of 0.5% was placed in the reaction zone at a flow rate of 100 sccm, and the reaction temperature was controlled at 120~180℃ for 2 hours. S3: After the reaction in S2 is completed, the temperature is lowered to room temperature and solid selenium powder is placed upstream of the tube furnace. Then, a mixed gas with an argon-hydrogen volume ratio of 9:1 is introduced, and the selenium powder is heated to generate selenium vapor. Finally, the composite fiber is heated to 650°C at a heating rate of 5°C / min and the reaction is continued for 2 hours. S4: After the reaction is complete and cooled to room temperature, the mixture is ball-milled at 200 rpm for 5 minutes to obtain short fibrous powder. Particles with a D50 particle size of 10 μm are collected by sieving. The short fibrous powder, PVDF, and SP are then mixed at a mass ratio of 98.5:1.0:0.5 and subsequently placed in N-methylpyrrolidone for further mixing. Finally, the coating is prepared with an areal density of 2.5 mg / L. The coating is evenly applied to the copper foil current collector, dried in an 80℃ oven and rolled, and then transferred to a 120℃ vacuum drying oven for 12 hours.

[0041] Experimental results: See Table 4 for details.

[0042] Table 4: Test Results of Example 4 The molar concentration of molybdenum tetracarbonyl vapor was reduced to 0.5%, significantly decreasing the supply of molybdenum source during vapor deposition, leading to the formation of Mo... Insufficient loading of active material. Although a lower loading is beneficial for mitigating volumetric strain during cycling and improving capacity retention, the reduction in the total amount of active material directly decreases the specific capacity of the material. At the same time, the decrease in the density of the conductive network per unit volume leads to a deterioration in rate performance and electrode resistance.

[0043] Example 5 This embodiment provides a method for preparing agglomeration-resistant, highly conductive graphene anode material, the specific implementation steps of which include: Experimental materials: Graphene oxide, polyvinyl alcohol aqueous solution, Tetracarbonyl molybdenum, selenium powder, PVDF, SP, NMP.

[0044] Experimental objective: Adjust the sieve particle size range of the powder after ball milling.

[0045] Experimental steps: S1: Graphene oxide is uniformly dispersed in a polyvinyl alcohol aqueous solution at a mass ratio of 1:10 to form a spinnable precursor solution. Then, the precursor solution is spun using an electrospinning device at a voltage of 25kV, a feeding speed of 1.5mL / h, a receiving distance of 20cm, an ambient relative humidity of less than 40%, and a temperature of 25℃. The graphene oxide / polyvinyl alcohol composite fiber membrane with a three-dimensional interconnected network structure is collected on the receiving plate. S2: The prepared graphene oxide / polyvinyl alcohol composite fiber membrane is placed in a tube furnace and then circulated with... Molybdenum tetracarbonyl vapor with a carrier molar concentration of 2% was placed in the reaction zone at a flow rate of 100 sccm, and the reaction temperature was controlled at 180℃ for 2 hours. S3: After the reaction in S2 is completed, the temperature is lowered to room temperature and solid selenium powder is placed upstream of the tube furnace. Then, a mixed gas with an argon-hydrogen volume ratio of 9:1 is introduced, and the selenium powder is heated to generate selenium vapor. Finally, the composite fiber is heated to 650°C at a heating rate of 5°C / min and the reaction is continued for 2 hours. S4: After the reaction is complete and cooled to room temperature, the mixture is ball-milled at 200 rpm for 5 minutes to obtain short fibrous powder. Particles with a diameter of D100 are collected by sieving. The short fibrous powder, PVDF, and SP are then mixed at a mass ratio of 98.5:1.0:0.5 and subsequently placed in N-methylpyrrolidone for further mixing. Finally, the coating is prepared with an areal density of 2.5 mg / L. The coating is evenly applied to the copper foil current collector, dried in an 80℃ oven and rolled, and then transferred to a 120℃ vacuum drying oven for 12 hours.

[0046] Experimental results: See Table 5 for details.

[0047] Table 5: Test Results of Example 5 In Example 5, by collecting D100-sized particles during sieving, the material contains a large number of larger fiber aggregates. The larger particles increase the ion transport path and reduce the effective specific surface area of ​​the material, resulting in insufficient electrolyte wetting and increased charge transfer resistance. Therefore, although the initial capacity is relatively less affected, the rate performance is significantly reduced and the electrode resistance is significantly increased.

[0048] Comparative Example 1 This embodiment provides a traditional method for preparing agglomeration-resistant, highly conductive graphene anode material, the specific implementation steps of which include: Experimental materials: Graphene oxide, ammonium molybdate, selenium powder, PVDF, SP, N-methylpyrrolidone.

[0049] Experimental objective: Mo prepared by traditional mechanical mixing-high temperature selenization method / Graphene composite materials.

[0050] Experimental steps: S1: Graphene oxide and ammonium molybdate are ultrasonically dispersed in deionized water at a mass ratio of 10:1 to obtain a mixed slurry; S2: Dry the mixed slurry at 80°C for 24 hours to obtain precursor powder; S3: The precursor powder and selenium powder are mixed in stoichiometric ratio and placed in a tube furnace. The temperature is increased to 650℃ at 5℃ / min under an argon atmosphere and held for 2 hours to carry out the selenization reaction. S4: After the reaction is completed, the product is naturally cooled, ball-milled and sieved to obtain composite powder, which is then mixed with PVDF and SP at a mass ratio of 98.5:1.0:0.5. N-methylpyrrolidone is added to form a slurry, which is then evenly coated onto copper foil. After drying at 80°C and rolling, it is vacuum dried at 120°C for 12 hours.

[0051] Experimental results: See Table 6 for details.

[0052] Table 6: Test Results of Comparative Example 1 Comparative Example 1 prepared Mo using a traditional mechanical mixing-high temperature calcination process. The graphene composite material method involves physically mixing graphene oxide with a molybdenum salt precursor, followed by high-temperature selenization to obtain the composite. However, this method lacks a three-dimensional continuous conductive framework and atomically dispersed molybdenum precursor active material Mo. It is prone to aggregation and does not bind tightly to the graphene support, resulting in poor electron / ion transport pathways and high interface resistance. The test results show that the initial discharge specific capacity is only 710 mAh / g, the capacity retention rate is 85% after 100 cycles, the capacity drops to 380 mAh / g at a high rate of 5A / g, and the electrode resistance is as high as about 65 Ω. The overall electrochemical performance is significantly lower than that of the embodiments of the present invention.

[0053] Example 1 employs an integrated process of electrospinning-vapor infiltration-simultaneous selenization reduction to construct a three-dimensional continuous graphene fiber network, achieving atomic-level dispersion of the molybdenum precursor and Mo... In-situ growth significantly improves the conductivity, structural stability and electrochemical performance of the material, achieving an optimal balance between capacity, cycling and rate performance.

[0054] Example 2 uses acetylene black instead of SP as a conductive agent. Although the overall process and core structure remain unchanged, the electrode interface resistance increases and the capacity and cycle performance decrease slightly due to the weak conductive network construction ability of acetylene black. However, it is still better than the traditional method.

[0055] Example 3 uses lower electrospinning parameters. Although it still maintains the three-dimensional fiber skeleton, the fiber uniformity and network continuity are reduced, which affects the uniformity of the loading of active materials and the electron transport efficiency, resulting in a decrease in overall performance compared with Example 1.

[0056] Example 4 uses a lower concentration of molybdenum tetracarbonyl vapor, which is beneficial for alleviating volume strain and improving capacity retention during cycling. However, due to insufficient active material loading, the specific capacity and rate performance are significantly reduced. It is suitable for application scenarios with high requirements for cycling stability and relatively relaxed requirements for capacity.

[0057] Example 5 uses a larger particle size screening method, which simplifies the post-processing steps. However, due to the increased particle size and reduced specific surface area, the electrolyte wettability and ion transport kinetics deteriorate, resulting in a significant deterioration in rate performance and resistance. It is suitable for low-rate, high-capacity applications.

[0058] Comparative Example 1 uses a traditional mechanical mixing-high temperature selenization process, which lacks a three-dimensional conductive framework and atomic-level dispersion mechanism, resulting in severe aggregation of active materials, weak interfacial bonding, and overall poor electrochemical performance, highlighting the fundamental limitations of traditional methods in material structure control.

[0059] Comparing the examples and comparative examples, Example 1 achieves the optimal balance between active material loading, conductive network continuity, interfacial bonding strength, and electrochemical kinetics. Through a multi-level structure control strategy of electrospinning framework—CVD uniform deposition—synchronous selenization reduction, the overall electrochemical performance and structural stability of the material are improved, making it suitable for lithium-ion battery anode materials with high energy density and long cycle life. Although the conductive network of Example 2 is slightly weakened, it still has the advantages of core-shell structure and three-dimensional framework. Example 3 uses lower spinning parameters, and although the performance is slightly reduced, it is still significantly better than the traditional process. Example 4 uses a low molybdenum source concentration, which improves cycle stability at the expense of some capacity. Example 5 uses large particle size screening, which simplifies the process but limits rate performance.

[0060] The comparative examples demonstrate the limitations of traditional mechanical mixing methods in terms of dispersion uniformity, structural integration, and performance consistency. It is evident that this invention fundamentally solves the problem of graphene and active material aggregation, achieving efficient preparation of highly conductive, highly stable, and high-performance anode materials, and possessing significant prospects for industrial application.

[0061] refer to Figure 1 The flowchart illustrates the preparation method, which mainly includes the following four key steps: First, graphene oxide is uniformly dispersed in a polyvinyl alcohol solution using electrospinning technology to form a composite fiber membrane with a three-dimensional interconnected network structure, constructing a stable and continuous conductive framework. Then, in a nitrogen atmosphere, a tetracarbonyl molybdenum precursor is uniformly loaded onto the fiber surface and pores via vapor deposition. Next, selenium powder is heated in an argon-hydrogen mixture to generate selenium vapor, simultaneously achieving the selenization of the molybdenum precursor and the reduction of graphene oxide to form Mo… The graphene core-shell composite structure is then subjected to ball milling, sieving, pulping, coating, and drying to obtain a negative electrode material with uniform structure, high conductivity, and excellent anti-agglomeration performance. This process intuitively demonstrates the complete process route from raw material processing to the final product, reflecting the synergistic effect and logical relationship between each step and the structural evolution.

[0062] 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.

[0063] 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 method for preparing an anti-agglomeration, highly conductive graphene anode material, characterized in that, Specifically, the following steps are included: S1: Graphene oxide is uniformly dispersed in a polyvinyl alcohol aqueous solution to form a spinnable precursor solution. The precursor solution is then spun using an electrospinning device, and a graphene oxide / polyvinyl alcohol composite fiber membrane with a three-dimensional interconnected network structure is collected on a receiving plate. S2: The prepared graphene oxide / polyvinyl alcohol composite fiber membrane is placed in a tube furnace and then circulated with... Tetracarbonyl molybdenum vapor, supported by a carrier, undergoes a vapor-phase deposition reaction in the reaction zone; S3: After the reaction in S2 is completed, the temperature is lowered to room temperature and solid selenium powder is placed upstream of the tube furnace. Then, an argon-hydrogen mixture is introduced, and the selenium powder is heated to generate selenium vapor. Finally, the composite fiber is heated to react with selenium. S4: After the reaction is complete and cooled to room temperature, the composite fiber membrane is ball-milled, and the particles are collected by sieving. Then, short fiber powder, PVDF, and SP are mixed and added to N-methylpyrrolidone. Finally, the coating is evenly applied to the copper foil current collector, dried in an oven and rolled, and then transferred to a vacuum drying oven to obtain the product with Mo... / Graphene core-shell structured graphene anode material with anti-agglomeration and high conductivity.

2. The method for preparing the anti-agglomeration highly conductive graphene anode material as described in claim 1, characterized in that, In S1, graphene oxide is uniformly dispersed in a polyvinyl alcohol aqueous solution at a mass ratio of 1:5~10.

3. The method for preparing the anti-agglomeration highly conductive graphene anode material as described in claim 1, characterized in that, In S1, the voltage of the electrospinning equipment is set to 15~25kV, the injection speed is 0.5~1.5mL / h, the receiving distance is 10~20cm, the relative humidity is less than 40±5%, and the ambient temperature is 25±3℃.

4. The method for preparing the anti-agglomeration highly conductive graphene anode material as described in claim 1, characterized in that, In S2, molybdenum tetracarbonyl vapor is mixed into the carrier at a molar concentration of 0.5-2%. It is placed in the reaction zone at a flow rate of 100 sccm.

5. The method for preparing the anti-agglomeration highly conductive graphene anode material as described in claim 1, characterized in that, In S2, the tube furnace is heated at 5℃ / min to 120~180℃ and the reaction is continued for 2 hours.

6. The method for preparing the anti-agglomeration highly conductive graphene anode material as described in claim 1, characterized in that, In S3, argon and hydrogen are uniformly mixed at a volume ratio of argon:hydrogen = 9:

1.

7. The method for preparing the anti-agglomeration highly conductive graphene anode material as described in claim 1, characterized in that, In S3, the composite fibers are heated to 500~600℃ at a rate of 5℃ / min and reacted continuously for 2 hours.

8. The method for preparing the anti-agglomeration highly conductive graphene anode material as described in claim 1, characterized in that, In S4, the composite fibers obtained after the reaction are ball-milled at a speed of 200-300 rpm for 5 minutes to obtain short fiber powder, and the short fiber powder is sieved to collect particles with D50 of 10-20 μm.

9. The method for preparing the anti-agglomeration highly conductive graphene anode material as described in claim 1, characterized in that, In S4, short fiber powder, PVDF, and SP are mixed in a mass ratio of 97-98.5:1.0-2:0.5-1. The mixture is then dissolved in N-methylpyrrolidone to obtain a coating. The coating is then prepared with an areal density of 1.5-2.5 mg / L. The coating is evenly applied to the copper foil current collector, then dried in an oven at 80-85℃ and rolled, and finally dried in a vacuum drying oven at 120℃ for 12 hours.

10. The method for preparing the anti-agglomeration highly conductive graphene anode material as described in claim 1, characterized in that, S4 as described The graphene core-shell structure is The nanosheets are uniformly loaded onto the surface of graphene fibers to form a tightly bonded core-shell composite structure.

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