Preparation method and application of dry conductive adhesive
A fibrous conductive binder was prepared by electrospinning a modified fluoropolymer with polyacrylonitrile. This process solved the problems of dispersion and interfacial bonding of conductive binders, improved conductivity and mechanical strength, and is suitable for high-performance composite materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- FOSHAN SINO SCI NANO TECH MATERIAL CO LTD
- Filing Date
- 2026-01-27
- Publication Date
- 2026-04-21
AI Technical Summary
Existing conductive binders have shortcomings in terms of dispersibility, interfacial bonding, mechanical properties and durability, making it difficult to meet the needs of high-performance composite materials. In addition, traditional processes are inefficient and costly.
A fibrous conductive binder was prepared by combining a modified fluoropolymer with polyacrylonitrile through electrospinning and pre-crosslinking processes. This optimized the dispersion and crosslinking structure of the conductive carbon material, resulting in a stable three-dimensional conductive network.
It improves conductivity, mechanical strength and thermal stability, enhances the adhesion strength with electrode active materials, ensures reliability and safety in harsh environments, and enables the construction of efficient conductive networks.
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Figure CN121895894A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery materials technology, and more specifically, to a method for preparing and applying a dry conductive binder. Background Technology
[0002] Conductive binders are widely used in electronic devices, energy equipment (such as lithium-ion batteries and supercapacitors), electromagnetic shielding materials, and aerospace composite materials. Their core function is to achieve a stable connection between materials and establish an efficient conductive path. Traditional conductive binders mostly use polymers such as epoxy resins and polyurethanes as the matrix, and achieve conductivity by directly incorporating conductive fillers such as carbon black, metal powders, or carbon fibers. However, these binders generally suffer from the following problems: First, the dispersion uniformity of conductive fillers is difficult to control, and agglomeration is prone to occur, resulting in discontinuous conductive networks, unstable conductivity, and anisotropy. Second, the addition of fillers often significantly deteriorates the mechanical properties of the matrix polymer, especially the toughness and adhesion. Third, conventional mechanical blending methods cannot precisely control the morphology and spatial distribution of conductive fillers, making it impossible to achieve the structural design of conductive paths, thus limiting their application in high-performance, multifunctional composite materials.
[0003] In recent years, carbon nanotubes (CNTs) and graphene, among other carbon nanomaterials, have been widely studied as conductive fillers due to their excellent conductivity, high specific surface area, and mechanical strength. However, carbon nanomaterials also face challenges in polymer matrices, such as dispersion difficulties and weak interfacial bonding, and their cost increases dramatically with high addition levels. Furthermore, existing conductive binders lack durability under harsh environments (such as high temperatures and strong corrosion), especially when used in carbon fiber reinforced composites or ceramic matrix composites, often resulting in interfacial failure and degradation of conductivity.
[0004] Electrospinning technology can prepare continuous ultrafine fibers, making it possible to construct ordered conductive structures at the micro- and nano-scale. However, its application in the preparation of conductive adhesives is currently rare. Furthermore, how to further process electrospun fibers into morphologies suitable for use as adhesives and effectively composite them with other reinforcing materials remains a pressing technical challenge. Therefore, developing a novel method for preparing conductive adhesives with excellent conductivity, good mechanical properties, controllable structure, and applicability to high-performance composite materials is of great significance.
[0005] Current dry processes involve the thorough mixing and dispersion of powders (electrode active materials, conductive agents, and binders), followed by the formation of a film through sufficient contact between the binder and the surface of inorganic particles. However, because the adhesion between particles is point-to-point contact, the binder utilization rate is low, requiring a large amount of binder (typically 5-20%) to achieve the desired film formation. Polytetrafluoroethylene (PTFE) is the most commonly used binder with good adhesion. However, PTFE also has significant drawbacks, such as non-stickiness to the current collector and instability in the negative electrode electrochemical environment, thus limiting its application development. Furthermore, it is prone to agglomeration during processing, affecting the continuity and conductivity of the conductive network. Summary of the Invention
[0006] In view of this, and in order to solve one of the above-mentioned technical problems, the present invention provides a method for preparing and applying a dry conductive adhesive, the specific technical solution of which is as follows: A method for preparing a dry conductive adhesive, the method comprising the following steps: S1. Add conductive carbon material to the dispersion medium, ultrasonically disperse it, then add modified fluorinated polymer, polyacrylonitrile and thickener, stir to obtain a uniform spinning precursor solution. S2. Electrospinning the spinning precursor solution to obtain composite fiber filaments; S3. After drying the composite fiber filaments, a pre-crosslinking treatment is performed to obtain a coarse conductive adhesive; S4. The coarse conductive adhesive is subjected to airflow pulverization to obtain a dry conductive adhesive.
[0007] Furthermore, the conductive carbon material is at least one of carbon nanotubes, graphene, graphite, and carbon black.
[0008] Further, in step S1, the modified fluorinated polymer is prepared by adding fluorinated monomers to N,N-dimethylformamide, dissolving them completely, then adding 2-mercaptobenzyl alcohol, polyoxyethylene ether and triethylamine, stirring and reacting, and then washing, precipitating, filtering and drying to obtain the product.
[0009] Furthermore, the fluorine monomer is at least one selected from vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, hexafluoropropylene, and octafluorobutene.
[0010] Further, by weight, the ratio of the fluorinated monomer, N,N-dimethylformamide, 2-mercaptobenzyl alcohol, polyoxyethylene ether and triethylamine is (1~5):(8~12):(1~3):(2~5):(0.1~0.5).
[0011] Furthermore, the stirring reaction was carried out at a temperature of 65℃~70℃ and a rotation speed of 50r / min~100r / min for 6h~10h.
[0012] Further, in step S1, the dispersion medium is at least one selected from N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and methanol.
[0013] Further, in step S1, the ratio of the conductive carbon material, dispersion medium, modified fluorinated polymer, polyacrylonitrile and thickener by weight is (1~10):(20~30):(8~20):(3~5):(0.5~3).
[0014] Further, in step S2, the electrospinning process is as follows: the spinning voltage is 20kV~25kV, the spinning distance is 10cm~20cm, and the spinning speed is 0.5~2mL / h.
[0015] In addition, the present invention also provides an application of a dry conductive binder, wherein the dry conductive binder prepared by the preparation method is used in the preparation of a dry electrode self-supporting film or as a supercapacitor electrode material.
[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention involves compounding a modified fluoropolymer prepared using a specific method with polyacrylonitrile, and then combining this with electrospinning and a stepwise pre-crosslinking process to obtain a conductive adhesive with excellent conductivity, mechanical strength, and thermal stability. The modified fluoropolymer incorporates hydroxyl groups and polyether segments, providing chemical inertness and flexibility, and interacts with polyacrylonitrile to balance adhesion and conductivity.
[0017] 2. This invention significantly improves the interfacial interaction between the polymer matrix and the conductive carbon material by adding hydroxyl functional groups introduced into the modified fluoropolymer. The pre-crosslinking process helps to promote the formation of a strong chemical crosslinking network inside the fiber, which significantly increases the bonding strength of the conductive adhesive with the electrode active material and current collector in subsequent applications, and effectively suppresses the peeling failure of the electrode caused by volume expansion or cyclic stress during use.
[0018] 3. This invention optimizes the process by ultrasonically dispersing the conductive carbon material, which helps to achieve uniform distribution in the spinning precursor and ensures the nanoscale dispersion of the conductive carbon material in the fiber. Furthermore, the electrospinning process encapsulates the conductive carbon material within the continuous fiber, and then airflow pulverization yields fibrous conductive binders of specific sizes. This allows the conductive binders to physically overlap and entangle during application, constructing a stable three-dimensional interpenetrating conductive network on a macroscopic scale. Compared to the point contact network formed by direct blending of traditional powder fillers, this invention exhibits lower contact resistance, higher structural stability, and resistance to repeated deformation, resulting in superior overall performance.
[0019] 4. The dry conductive adhesive prepared by this invention is fibrous. Compared with powdered adhesives, short fibers are easier to uniformly disperse in dry powder mixing and can mechanically interlock and entangle with fibers during roll forming to form a self-supporting electrode film with excellent mechanical integrity and high porosity. This eliminates the need for solvents and lengthy drying processes required in traditional wet processes, resulting in energy savings and environmental friendliness. Furthermore, the adhesive has a stable composition, is resistant to electrolyte corrosion, and its cross-linked structure and modified fluoropolymer ensure reliability and safety under long-term cycling or high-temperature operating environments in devices such as supercapacitors. Attached Figure Description
[0020] The invention will be further understood from the following description taken in conjunction with the accompanying drawings. The components in the drawings are not necessarily drawn to scale, but rather the emphasis is on illustrating the principles of the embodiments. In different views, the same reference numerals designate corresponding parts.
[0021] Figure 1 This is a schematic diagram of the process of preparing a dry conductive adhesive in Embodiment 1 of the present invention, in which composite fiber filaments are obtained by electrospinning. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to its embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of the invention.
[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0024] A method for preparing a dry conductive adhesive according to an embodiment of the present invention includes the following steps: S1. Add conductive carbon material to the dispersion medium, ultrasonically disperse it, then add modified fluorinated polymer, polyacrylonitrile and thickener, stir to obtain a uniform spinning precursor solution. S2. Electrospinning the spinning precursor solution to obtain composite fiber filaments; S3. After drying the composite fiber filaments, a pre-crosslinking treatment is performed to obtain a coarse conductive adhesive; S4. The coarse conductive adhesive is subjected to airflow pulverization to obtain a dry conductive adhesive.
[0025] In one embodiment, the conductive carbon material is at least one of carbon nanotubes, graphene, graphite, and carbon black.
[0026] In one embodiment, in step S1, silver ions may be added to the spinning precursor solution, and the amount of silver ions added accounts for 0.0001% to 0.0005% of the mass of the spinning precursor solution.
[0027] In one embodiment, in step S1, the modified fluorinated polymer is prepared by adding fluorinated monomers to N,N-dimethylformamide, dissolving them completely, then adding 2-mercaptobenzyl alcohol, polyoxyethylene ether, and triethylamine, stirring and reacting, and then washing, precipitating, filtering, and drying to obtain the product.
[0028] In one embodiment, the fluorine monomer is at least one selected from vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, hexafluoropropylene, and octafluorobutene.
[0029] In one embodiment, the ratio of the fluorinated monomer, N,N-dimethylformamide, 2-mercaptobenzyl alcohol, polyoxyethylene ether, and triethylamine by weight is (1~5):(8~12):(1~3):(2~5):(0.1~0.5).
[0030] In one embodiment, the stirring reaction is carried out at a temperature of 65°C to 70°C and a rotation speed of 50 r / min to 100 r / min for 6 h to 10 h.
[0031] In one embodiment, in step S1, the dispersion medium is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and methanol.
[0032] In one embodiment, in step S1, the thickener is at least one of sodium carboxymethyl cellulose, polyvinyl alcohol, polyethylene oxide, and sodium alginate.
[0033] In one embodiment, in step S1, the ratio of the conductive carbon material, dispersion medium, modified fluorinated polymer, polyacrylonitrile and thickener by weight is (1~10):(20~30):(8~20):(3~5):(0.5~3).
[0034] In one embodiment, in step S1, the ultrasonic dispersion power is 50W~200W, the frequency is 20kHz~25kHz, and the time is 10min~30min.
[0035] In one embodiment, in step S1, the stirring process is performed at a temperature of 55℃~70℃ and a rotation speed of 100r / min~500r / min for 1h~3h.
[0036] In one embodiment, in step S2, the electrospinning process is as follows: the spinning voltage is 20kV~25kV, the spinning distance is 10cm~20cm, and the spinning speed is 0.5~2mL / h.
[0037] In one embodiment, in step S3, the pre-crosslinking treatment is as follows: the temperature is increased to 50°C to 65°C at a heating rate of 3 to 5°C and held for 20 to 30 minutes, and then the temperature is increased to 80°C to 120°C and held for 1 to 3 hours.
[0038] In one embodiment, in step S4, the conductive adhesive obtained by air jet milling has a diameter of 200nm~500nm and a length of 0.5mm~1mm.
[0039] In addition, the present invention also provides an application of a dry conductive binder, wherein the dry conductive binder prepared by the preparation method is used in the preparation of a dry electrode self-supporting film or as a supercapacitor electrode material.
[0040] In one embodiment, the dry electrode self-supporting film is prepared by blending a conductive binder, carbon fiber reinforced composite material (CPF reinforcement), and silicon carbide, followed by post-treatment to obtain the dry electrode self-supporting film.
[0041] The above-mentioned scheme, through optimization of composition and process, can obtain a dry conductive adhesive with excellent conductivity, adhesion and stability. It can be used in the preparation of dry electrode self-supporting films or as a supercapacitor electrode material, so that the dry electrode self-supporting film or supercapacitor electrode material has excellent comprehensive performance.
[0042] The implementation schemes of the present invention will now be described in detail with reference to specific embodiments.
[0043] Example 1: A method for preparing a dry conductive adhesive, the method comprising the following steps: S1. By weight, 7 parts of carbon nanotubes were added to 20 parts of N,N-dimethylformamide and ultrasonically dispersed for 15 min at a power of 100 W and a frequency of 25 kHz. Then, 12 parts of modified fluorinated polymer, 4 parts of polyacrylonitrile and 1 part of sodium carboxymethyl cellulose were added and stirred for 2 h at a temperature of 65 ℃ and a speed of 300 r / min to obtain a uniform spinning precursor solution. The modified fluorinated polymer is prepared by adding 5 parts by weight of vinylidene fluoride to 10 parts of N,N-dimethylformamide, dissolving it completely, then adding 2 parts of 2-mercaptobenzyl alcohol, 3 parts of polyoxyethylene ether and 0.1 parts of triethylamine, stirring and reacting for 6 hours at a temperature of 65°C and a rotation speed of 50 r / min, and then obtaining the product after washing, precipitation, filtration and drying. S2. The spinning precursor solution is electrospun at a spinning voltage of 20kV, a spinning distance of 20cm, and a spinning speed of 1mL / h to obtain composite fiber precursor. S3. After drying the composite fiber filament, heat it to 55°C at a heating rate of 3°C and keep it at that temperature for 30 minutes. Then, continue to heat it to 105°C and keep it at that temperature for 1 hour to obtain a coarse conductive adhesive. S4. The coarse conductive adhesive is subjected to airflow pulverization to obtain a dry conductive adhesive.
[0044] Example 2: A method for preparing a dry conductive adhesive, the method comprising the following steps: S1. By weight, 8 parts of carbon nanotubes were added to 20 parts of N,N-dimethylformamide and ultrasonically dispersed for 20 min at a power of 100 W and a frequency of 25 kHz. Then, 15 parts of modified fluorinated polymer, 5 parts of polyacrylonitrile and 1 part of sodium carboxymethyl cellulose were added and stirred for 2 h at a temperature of 70 °C and a speed of 300 r / min to obtain a uniform spinning precursor solution. The modified fluorinated polymer is prepared by adding 5 parts by weight of tetrafluoroethylene to 10 parts of N,N-dimethylformamide, dissolving it completely, then adding 3 parts of 2-mercaptobenzyl alcohol, 2 parts of polyoxyethylene ether and 0.1 parts of triethylamine, stirring and reacting for 6 hours at a temperature of 70°C and a rotation speed of 50 r / min, and then obtaining the product after washing, precipitation, filtration and drying. S2. The spinning precursor solution is electrospun at a spinning voltage of 20kV, a spinning distance of 20cm, and a spinning speed of 1mL / h to obtain composite fiber precursor. S3. After drying the composite fiber filament, heat it to 60°C at a heating rate of 4°C and keep it at that temperature for 25 minutes. Then continue to heat it to 105°C and keep it at that temperature for 1 hour to obtain a coarse conductive adhesive. S4. The coarse conductive adhesive is subjected to airflow pulverization to obtain a dry conductive adhesive.
[0045] Example 3: A method for preparing a dry conductive adhesive, the method comprising the following steps: S1. By weight, 10 parts of carbon nanotubes were added to 25 parts of N,N-dimethylformamide and ultrasonically dispersed for 30 min at a power of 100 W and a frequency of 25 kHz. Then, 18 parts of modified fluorinated polymer, 5 parts of polyacrylonitrile and 1 part of sodium carboxymethyl cellulose were added and stirred for 2 h at a temperature of 70 °C and a speed of 300 r / min to obtain a uniform spinning precursor solution. The modified fluorinated polymer is prepared by adding 5 parts by weight of fluorinated vinylidene to 10 parts of N,N-dimethylformamide, dissolving it completely, then adding 3 parts of 2-mercaptobenzyl alcohol, 2 parts of polyoxyethylene ether and 0.1 parts of triethylamine, stirring and reacting for 6 hours at a temperature of 70°C and a rotation speed of 50 r / min, and then obtaining the product after washing, precipitation, filtration and drying. S2. The spinning precursor solution is electrospun at a spinning voltage of 20kV, a spinning distance of 20cm, and a spinning speed of 1mL / h to obtain composite fiber precursor. S3. After drying the composite fiber filament, heat it to 65°C at a heating rate of 5°C and keep it at that temperature for 25 minutes. Then continue to heat it to 105°C and keep it at that temperature for 1 hour to obtain a coarse conductive adhesive. S4. The coarse conductive adhesive is subjected to airflow pulverization to obtain a dry conductive adhesive.
[0046] Comparative Example 1: The difference between Comparative Example 1 and Example 3 is that the process of step S1 in Comparative Example 1 is different, while the rest is the same as in Example 3. The process of S1 in Comparative Example 1 is as follows: 10 parts by weight of carbon nanotubes, 25 parts by weight of N,N-dimethylformamide, 18 parts by weight of modified fluorinated polymer, 5 parts by weight of polyacrylonitrile and 1 part by weight of sodium carboxymethyl cellulose are mixed and then stirred for 2 hours at a temperature of 70℃ and a rotation speed of 300 r / min to obtain a spinning precursor solution.
[0047] Comparative Example 2: The difference between Comparative Example 2 and Example 3 is that the preparation method of the modified fluorinated polymer in step S1 of Comparative Example 2 is different, while the rest is the same as in Example 3. The modified fluorinated polymer in Comparative Example 2 was prepared as follows: 5 parts by weight of fluorinated vinylidene were added to 10 parts of N,N-dimethylformamide and dissolved completely. Then, 5 parts of polyoxyethylene ether and 0.1 parts of triethylamine were added. The mixture was stirred and reacted for 6 hours at a temperature of 70°C and a rotation speed of 50 r / min. The product was then washed, precipitated, filtered, and dried to obtain the final product.
[0048] Comparative Example 3: The difference between Comparative Example 3 and Example 3 is that the preparation method of the modified fluorinated polymer in step S1 of Comparative Example 3 is different, while the rest is the same as Example 3. The modified fluorinated polymer in Comparative Example 3 was prepared as follows: 5 parts by weight of fluorinated vinylide were added to 10 parts of N,N-dimethylformamide and dissolved completely. Then, 5 parts of 2-mercaptobenzyl alcohol and 0.1 parts of triethylamine were added. The mixture was stirred for 6 hours at a temperature of 70°C and a rotation speed of 50 r / min. The product was then washed, precipitated, filtered, and dried to obtain the final product.
[0049] Comparative Example 4: Compared with Example 3, Comparative Example 4 differs in that in step S1, polytetrafluoroethylene is used to replace the modified fluoropolymer, while the rest is the same as in Example 3.
[0050] Comparative Example 5: The difference between Comparative Example 5 and Example 3 is that the pre-crosslinking treatment process in step S3 of Comparative Example 5 is different, while the rest is the same as Example 3. The pre-crosslinking process in step S3 of Comparative Example 5 is as follows: the temperature is raised to 85°C at a heating rate of 8°C and held for 1 hour.
[0051] Comparative Example 6: The difference between Comparative Example 6 and Example 3 is that Comparative Example 6 did not undergo pre-crosslinking treatment, but otherwise it was the same as Example 3.
[0052] I. The dry conductive adhesive samples prepared in Examples 1-3 and the dry conductive adhesive samples prepared in Comparative Examples 1-6 were subjected to performance tests. The tensile shear strength and thermal conductivity of the dry conductive adhesive were tested in accordance with the standards HG / T5912-2021 and GB / T 7124-2008. The results are shown in Table 1 below.
[0053] Table 1: Performance Test Results
[0054] As can be seen from the data analysis in Table 1, the dry conductive adhesive of the present invention, after optimization of its composition, possesses excellent interfacial bonding strength and internal cross-linking network strength. Furthermore, the improved dispersion uniformity and the continuity of the internal conductive network of the fiber have a certain promoting effect on thermal stability. Compared to Example 3, Comparative Example 1 did not undergo ultrasonic treatment, resulting in uneven dispersion of carbon nanotubes, agglomeration, discontinuous conductive pathways, and poor dispersibility. This led to weak interfacial bonding with the matrix, affecting shear strength and resulting in overall performance inferior to Example 3. Comparative Examples 2 and 3 used different methods for preparing the modified fluoropolymers. Comparative Example 4 used polytetrafluoroethylene instead of the modified fluoropolymer, but the conductive binder's performance was inferior to Example 3. This indicates that the addition of specific modified fluoropolymers in this invention has a positive effect on the overall dispersion, adhesion, and interfacial bonding of the conductive binder, giving it better application performance. In Comparative Example 5, the pre-crosslinking heating rate was too fast, and the staged heating crosslinking treatment was not performed, resulting in uneven crosslinking, affecting the integrity of the internal network, and thus affecting the performance of the conductive binder. Comparative Example 6 did not undergo pre-crosslinking treatment, resulting in a loose structure and poor crosslinking performance, leading to performance inferior to Example 3.
[0055] II. Dry electrode support films were prepared from the dry adhesive samples prepared in Examples 1-3 and Comparative Examples 1-6, respectively. The preparation method of the dry electrode support film is as follows: 55 parts by weight of polyvinyl chloride, 20 parts by conductive adhesive, 15 parts by polyvinyl alcohol, and 10 parts by polyaniline are blended and hot-pressed to obtain dry electrode support films. Those skilled in the art applied this to batteries using conventional techniques and subjected the batteries to cyclic charge-discharge cycles to evaluate capacity retention. Charging conditions: first, constant current charging at 0.5C to 3.65V, then constant voltage charging at 3.65V to a cutoff current of 0.05C; discharging conditions: constant current discharge at 0.5C to a cutoff voltage of 2.0V; test environment temperature 25℃; test results after 500 cycles are shown in Table 2 below.
[0056] Table 2: Cycle life results
[0057] Analysis of the data in Table 2 shows that the present invention, by optimizing the composition of the binder, exhibits excellent cycling stability in application. This demonstrates that the dry conductive binder prepared by the present invention can construct a stable three-dimensional conductive network in dry electrodes, effectively suppressing volume expansion and delamination of the electrode material during cycling and maintaining the continuity of electrochemical contact. Compared with Example 3, Comparative Example 1, which was not subjected to ultrasonic treatment, suffered from uneven dispersion, resulting in discontinuous conductive networks, easy local disconnection during cycling, and significant capacity decay. The different preparation methods of the modified fluoropolymers in Comparative Examples 2 and 3 resulted in insufficient interfacial bonding and flexibility, making them prone to microcracks during cycling and leading to a decrease in capacity retention. Comparative Example 4 used PTFE, which had weak interfacial bonding and poor conductivity, making the electrode structure prone to collapse during cycling and resulting in the lowest capacity retention. The altered pre-crosslinking processes in Comparative Examples 5 and 6 caused the binder to easily undergo plastic deformation or fracture under cyclic stress, affecting the stability of the electrode structure. This demonstrates that the conductive binder of the present invention has superior advantages in terms of structural integrity, interfacial bonding strength, and conductive network stability, enabling it to be directly converted into electrodes with high cycling stability and long lifespan in practical use.
[0058] in addition, Figure 1 In the preparation method of a dry conductive adhesive according to Embodiment 1 of the present invention, composite fiber precursors are obtained by electrospinning. Figure 1 It can be clearly seen that the prepared composite fiber precursor has a continuous and uniform fibrous morphology with a smooth fiber surface. Conductive carbon materials (such as carbon nanotubes) are uniformly coated and embedded in a polymer matrix composed of modified fluorinated polymer and polyacrylonitrile, forming a composite fiber with a uniformly dispersed structure.
[0059] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0060] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.
Claims
1. A method for preparing a dry conductive adhesive, characterized in that, The preparation method includes the following steps: S1. Add conductive carbon material to the dispersion medium, ultrasonically disperse it, then add modified fluorinated polymer, polyacrylonitrile and thickener, stir to obtain a uniform spinning precursor solution. S2. Electrospinning the spinning precursor solution to obtain composite fiber filaments; S3. After drying the composite fiber filaments, a pre-crosslinking treatment is performed to obtain a coarse conductive adhesive; S4. The coarse conductive adhesive is subjected to airflow pulverization to obtain a dry conductive adhesive.
2. The preparation method according to claim 1, characterized in that, The conductive carbon material is at least one of carbon nanotubes, graphene, graphite, and carbon black.
3. The preparation method according to claim 1, characterized in that, In step S1, the modified fluorinated polymer is prepared by adding fluorinated monomers to N,N-dimethylformamide, dissolving them completely, then adding 2-mercaptobenzyl alcohol, polyoxyethylene ether, and triethylamine, stirring and reacting, and then washing, precipitating, filtering, and drying to obtain the product.
4. The preparation method according to claim 3, characterized in that, The fluorine monomer is at least one of vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, hexafluoropropylene, and octafluorobutene.
5. The preparation method according to claim 3, characterized in that, The ratio of the fluorinated monomer, N,N-dimethylformamide, 2-mercaptobenzyl alcohol, polyoxyethylene ether and triethylamine by weight is (1~5):(8~12):(1~3):(2~5):(0.1~0.5).
6. The preparation method according to claim 3, characterized in that, The stirring reaction was carried out at a temperature of 65℃~70℃ and a rotation speed of 50r / min~100r / min for 6h~10h.
7. The preparation method according to claim 1, characterized in that, In step S1, the dispersion medium is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and methanol.
8. The preparation method according to claim 1, characterized in that, In step S1, the ratio of the conductive carbon material, dispersion medium, modified fluorinated polymer, polyacrylonitrile and thickener by weight is (1~10):(20~30):(8~20):(3~5):(0.5~3).
9. The preparation method according to claim 1, characterized in that, In step S2, the electrospinning process is as follows: the spinning voltage is 20kV~25kV, the spinning distance is 10cm~20cm, and the spinning speed is 0.5~2mL / h.
10. An application of a dry conductive adhesive, characterized in that, The application refers to the use of the dry conductive binder prepared by the preparation method described in claims 1 to 9 in the preparation of dry electrode self-supporting films or as a supercapacitor electrode material.