Method for efficiently preparing single-walled carbon nanotube slurry

Abstract

The invention belongs to the technical field of conductive carbon paste, and discloses a method for efficiently preparing single-walled carbon nanotube paste, which comprises the following steps of: 1, mixing single-walled carbon nanotube powder with a dispersing agent and a solvent, and dispersing the mixture into uniform carbon nanotube bundle paste in manners of mechanical stirring, emulsifying and the like; and step 2, enabling the uniform carbon nanotube bundle slurry to pass through different micropore channels for multiple times in a high-pressure environment, so that the carbon nanotube bundle slurry is dispersed into uniform single carbon nanotube slurry. Through a special high-pressure homogenizing channel, the adhered and wound single-walled carbon nanotube bundles can be dispersed into the slurry of the single single-walled carbon nanotubes on the premise of ensuring the lengths of the single-walled carbon nanotubes as much as possible. The uniform dispersion is realized, the tube diameter of the single-walled carbon nanotubes is relatively long, and the excellent conductivity of the slurry is ensured by the single single-walled carbon nanotubes and the microcosmic number of the single single-walled carbon nanotubes.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of conductive carbon paste, and discloses a method for efficiently preparing single-walled carbon nanotube paste. BACKGROUND

[0002] The existing single-walled carbon nanotube (SWCNT) paste preparation dispersion technology mainly includes physical method, chemical method, physical-chemical combination method and new spontaneous dispersion technology.

[0003] Physical dispersion is to break the agglomeration of carbon nanotubes through mechanical force (such as shearing, grinding, ultrasonic treatment, etc.) to achieve the purpose of dispersion. No chemical additives are needed in the dispersion process, which can reduce the influence on the conductivity, and the equipment is mature at present, which is suitable for large-scale production. However, the mechanical force may damage the structure of carbon nanotubes, leading to defects and the dispersion effect is highly dependent on the equipment, which is difficult to optimize. Typical methods include three-roll grinding, high-pressure homogenization and ultrasonic treatment. Three-roll grinding is to realize dispersion through the shearing force of the roller, which can uniformly disperse and not damage the structure of carbon nanotubes, but the efficiency is very low. High-pressure homogenization utilizes the cavitation effect, impact effect and shearing effect of the high-pressure homogenizer to achieve the effect of homogenization, pulverization and emulsification of liquid samples. Pure high-pressure homogenization for dispersing single-walled carbon nanotubes has the problems of low efficiency, high energy consumption and high required pressure, which is usually above 2000 bar, 10 passes and above, which is also a heavy burden on the equipment. Ultrasonic treatment is to use high-frequency vibration to break the agglomeration, but the time needs to be controlled to avoid a large number of carbon nanotube breakage.

[0004] Chemical dispersion method is to improve the solubility of carbon nanotubes through chemical modification or surfactant to achieve dispersion effect. This dispersion method has high stability and is widely used in various applications, which is suitable for water-based and organic solvent systems. It mainly includes covalent functionalization and non-covalent functionalization. Covalent functionalization is to use strong acid (such as nitric acid, sulfuric acid) to oxidize the surface and introduce functional groups (such as -COOH) to enhance the dispersibility; while non-covalent functionalization is to use surfactants (such as Pluronic F108) or polymers to wrap carbon tubes, and to stabilize the dispersion through intermolecular forces. However, covalent modification will damage the sp² structure of carbon tubes, reduce the conductivity and mechanical properties, and non-covalent modification needs to add a large amount of surfactant, which affects the overall performance of the material and limits the application.

[0005] In addition to simple physical dispersion method and chemical dispersion method, there are spontaneous dispersion technology, green dispersion technology and other process methods. Spontaneous dispersion technology is to realize spontaneous dispersion by using the selective functionalization of carbon nanotube by-products. For example, the super strong acid intercalation method is to use fuming sulfuric acid to intercalate carbon nanotube bundles, and to improve the solvent affinity by functionalizing by-products, without external force. This dispersion method involves strong acid treatment, which has high environmental pollution risk and harsh process conditions, and requires high control accuracy of reaction temperature and reaction time. Green dispersion technology is a kind of dispersion technology developed based on environmental protection and biocompatibility, such as Pluronic F108, which realizes biocompatibility dispersion through non-covalent modification; TUBALL™ series of OCSiAl, low dispersant addition amount, suitable for environmentally friendly coatings. This dispersion technology relies on newly developed dispersants, which affects the purity of the material and limits the application of the dispersion liquid, and the dispersion process is not mature enough for industrial production.

[0006] The most widely used dispersion method at present is the physical and chemical combined method, that is, the combination of mechanical force and chemical treatment method. This treatment process has high dispersion efficiency, and the combination of physical and chemical methods can reduce the amount of chemical reagents, improve the material purity of the finished slurry, and the production process is relatively environmentally friendly. However, this process requires multiple steps to cooperate (such as soaking, polymerization, grinding, etc.), and the dispersion equipment is used together with the dispersant, and the process is relatively complex, and single-walled carbon nanotubes are difficult to disperse completely, and the finished slurry usually contains a lot of broken and damaged single-walled carbon nanotubes, which affects the conductivity of the final product slurry. Typical processes include ultrasonic plus surfactant, that is, ultrasonic dispersion and agglomeration, and the surfactant makes the dispersion stable; in-situ polymerization plus high-pressure homogenization, that is, by soaking the carbon tube with polymerizable monomers, combined with grinding and homogenization to achieve multi-stage dispersion.

[0007] Single-walled carbon nanotubes are prone to agglomeration and entanglement due to their large aspect ratio and strong van der Waals force, forming carbon nanotube bundles that are difficult to disperse. This agglomeration state seriously affects the performance of single-walled carbon nanotubes and limits their application in practical applications. Therefore, how to achieve efficient and uniform dispersion of single-walled carbon nanotubes in solvents or matrices, especially to unbundle them into whole tubes and maintain their aspect ratio, is a key technical problem in the preparation of high-performance single-walled carbon nanotube conductive slurry.

[0008] Therefore, it is an urgent problem to develop an efficient single-walled carbon nanotube industrial dispersion process and ensure the high conductivity of the finished slurry and the environmental friendliness of the production process. SUMMARY

[0009] The present application solves the problems of single-walled carbon nanotubes, such as difficult to disperse as a whole, affecting the conductive performance of the finished slurry; complex and non-environmental dispersion agent, limiting the application range of the finished slurry; complex industrial production process, low production efficiency and high cost; the current micro-jet homogenization technology for dispersing single-walled carbon nanotubes generally has high homogenization pressure, low efficiency, high equipment requirements, large crushing of single-walled carbon nanotubes, easy agglomeration of single-walled carbon nanotubes in the slurry, and uneven dispersion.

[0010] The present application provides a method for efficiently preparing single-walled carbon nanotube slurry, which forms a uniformly dispersed single-walled carbon nanotube slurry by processes such as infiltration, mixing, pre-dispersion, and high-pressure stripping of single-walled carbon nanotubes. At the same time, during the high-pressure stripping process, the type of high-pressure microchannel is changed, and the single-walled carbon nanotubes can be efficiently dispersed with the help of a dispersant. This process can be industrialized with a micro-jet high-pressure homogenizer, effectively solving the problems of complex industrial production process, high homogenization dispersion pressure, and low efficiency.

[0011] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: A method for efficiently preparing single-walled carbon nanotube slurry, the specific steps are as follows: 1. Feeding, a certain amount of single-walled carbon nanotube powder, dispersant, and solvent are placed in a stirring tank. The mass fraction of single-walled carbon nanotubes is 0.1%-1%, the mass fraction of dispersant is 0.5%-1.5%, and the mass fraction of solvent is 97.5%-99.5%.

[0012] 2. Pre-mixing and stirring, open the high-speed dispersion of the stirring tank, and after the stirring and dispersion are completed, a uniformly mixed carbon nanotube bundle slurry is obtained; 3. Micro-jet homogenization, the carbon nanotube bundle slurry obtained after pre-mixing and stirring is passed through a high-pressure micro-jet homogenizer multiple times, and after dispersion is completed, a uniform single-walled carbon nanotube slurry is obtained. The micro-jet homogenization channel is a combination of micro-jet turbulent channels and conventional channels; the conventional channel type is one or more of "Z" type, "Y" type, "H" type, and "K" type.

[0013] 4. Sieving, the mesh size of the sieve is 60-300 mesh, and the single-walled carbon nanotube finished slurry is obtained.

[0014] Further, in step 1, the dispersant is one of CMC (carboxymethyl cellulose), PVDF (polyvinylidene fluoride), and PVP (polyvinylpyrrolidone); and the solvent is one of NMP (N-methyl pyrrolidone), pure water, ethanol, and isopropyl alcohol.

[0015] Further, in step 2, high-speed dispersion adopts emulsification dispersion or high-speed stirring dispersion; wherein the time of high-speed stirring dispersion is 2-10h, the speed of high-speed stirring dispersion is 600rpm-3000rpm, the diameter of a dispersion disc is 40mm-400mm; the time of emulsification dispersion is 1-6h, the shear speed of emulsification dispersion is 0.5krpm-20krpm, the diameter of a stator of emulsification is 40mm-350mm, and the power of an emulsification motor or a high-speed dispersion motor is 0.8kw-35kw.

[0016] Further, in step 3, after premixing and stirring, the carbon nanotube bundle slurry is first passed through a turbulent flow type homogenization channel and then passed through a conventional channel; the number of channels of a high-pressure microjet homogenizer in series is 2-4; the number of homogenization channels passing through the microjet homogenizer is 2-8, and the pressure of the microjet homogenizer is 500bar-2000bar.

[0017] Further, in step 3, the microjet turbulent flow channel comprises a first turbulent flow structure 1 and a second turbulent flow structure 2 in series, or comprises two first turbulent flow structures 1 in series, or comprises two second turbulent flow structures 2 in series. The first turbulent flow structure 1 comprises a plurality of stepped holes 11 connected in sequence along the slurry flow direction and gradually decreasing in hole diameter; the second turbulent flow structure 2 comprises an expansion hole 21, an equal-diameter hole 22 and a reduced-diameter hole 23 connected in sequence along the slurry flow direction; the hole diameter of the expansion hole 21 gradually increases along the slurry flow direction, the hole diameter of the reduced-diameter hole 23 gradually decreases along the slurry flow direction, and the maximum hole diameter of the reduced-diameter hole 23 is equal to the hole diameter of the equal-diameter hole 22.

[0018] The ratio of the maximum stepped hole 11 to the minimum stepped hole 11 in the first turbulent flow structure 1 is greater than or equal to 3; the contraction angle α or the expansion angle β in the second turbulent flow structure is greater than or equal to 50° and less than or equal to 150°. The minimum hole diameter of the stepped hole 11, the expansion hole 21, the equal-diameter hole 22 and the reduced-diameter hole 23 is less than or equal to 1000μm and greater than or equal to 0.1μm, and the maximum hole diameter of the stepped hole 11, the expansion hole 21, the equal-diameter hole 22 and the reduced-diameter hole 23 is less than or equal to 10mm and greater than or equal to 1μm.

[0019] The present application only needs 2-8 channels to achieve the dispersion requirement, has high dispersion efficiency and causes little damage to single-walled carbon nanotubes. The number of homogenization channels passing through the microjet homogenizer is determined according to the dispersion effect of the slurry, generally, the particle size D50 of the aqueous slurry is less than or equal to 0.1μm, the particle size D50 of the NMP slurry is less than or equal to 1μm, and the dispersion effect is good. The more complete the carbon nanotubes are, the less damage they have, and the better the conductivity of the slurry is.

[0020] Compared with the prior art, the present application has the following advantages: 1. The present application introduces a specific geometric shape (variable diameter) of the turbulent flow channel, and combines it in a specific series with the traditional homogenizing channel (such as Z-type valve). The turbulent flow channel has a variable diameter compared to other channels, and the fluid is subjected to forces that are not limited to the effects of fluid impact generated by other types of channels. This structure allows the slurry to generate fluid turbulence when passing through the turbulent flow channel under high pressure microjet, and the turbulent microclusters not only have lateral pulsation, but also have reverse motion relative to the total motion of the fluid. These microcluster movements not only increase the mixing and dispersion effect of the slurry, but also facilitate the opening of entangled single-walled carbon nanotubes during the impact of the slurry, making it easier for the dispersant to adhere to the surface of the single-walled carbon nanotube, and after the slurry enters the subsequent microjet channel, the single-walled carbon nanotube can be completely opened more simply. In addition, the turbulent flow channel has a larger pore size than the conventional microjet channel, which can play a pre-breaking role to prevent frequent blockage of the microchannel. Improve equipment utilization and practicality. By combining the turbulent flow channel with other types of microjet channels, only 2-8 channels are required to achieve dispersion requirements, achieving the effect of efficiently dispersing single-walled carbon nanotubes with little damage to single-walled carbon nanotubes. The present application is suitable for different dispersant and solvent systems.

[0021] 2. The process flow is simple, the control parameters are less, and it is suitable for large-scale batch production. No expensive and special dispersant is needed, and only through two simple dispersion steps, the single-walled carbon nanotube powder can be dispersed into uniform and complete single-walled carbon nanotube slurry.

[0022] 3. The dispersion is thorough, and the finished slurry has good stability. The finished single-walled carbon nanotube slurry obtained by the special homogenizing channel of the present application with the corresponding homogenizing pressure has good stability and excellent conductivity performance. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Schematic diagram of the turbulent flow channel of the microjet homogenizer; Figure 2 Transmission electron microscope (TEM) image of the finished single-walled carbon nanotube slurry in Example 1; Figure 3 Particle size change diagram of the slurry after microjet homogenization in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4.

[0024] In the figure: 1 - first turbulent structure, 11 - stepped hole, 2 - second turbulent structure, 21 - expansion hole, 22 - equal diameter hole, 23 - reduced diameter hole. DETAILED DESCRIPTION

[0025] The present application will be further described in detail through specific examples, but the present application is not limited to the following embodiments

[0026] Embodiment 1: A method for efficiently preparing single-walled carbon nanotube slurry is as follows: 1. Put 40 g of single-walled carbon nanotube powder, 60 g of CMC powder, and 9.9 kg of pure water into a dispersion tank.

[0027] 2. Disperse the motor at 3 kw, the dispersion disc diameter is 100 mm, open the high-speed dispersion, adjust the speed to 1500 rpm, and disperse for 4 h to obtain a single-walled carbon nanotube bundle slurry. The particle size D50 tested by a laser particle size analyzer is 392 μm; 3. In the microfluidic channel, a turbulent homogenization channel and a "Z" type homogenization channel are sequentially loaded, the homogenization pressure is adjusted to 1000 bar, the slurry obtained in step 2 is placed in the microfluidic homogenizer feed tank, and the microfluidic homogenizer is started. Wait for the slurry in the feed tank to pass through the microfluidic homogenizer into the discharge tank, and then pour the slurry in the discharge tank into the feed tank, so that the slurry repeatedly passes through the microfluidic homogenizer 4 times, and is sieved through a 60 mesh sieve to obtain a uniform single-walled carbon nanotube slurry with a particle size D50 of 0.083 μm; wherein the microfluidic turbulent channel is a first turbulent structure 1 and a second turbulent structure 2 connected in series, the first turbulent structure 1 comprises a plurality of stepped holes 11 connected in series along the flow direction of the slurry and gradually decreasing in hole diameter; the second turbulent structure 2 comprises an expansion hole 21, an equal-diameter hole 22 and a reduced-diameter hole 23 connected in series along the flow direction of the slurry; the hole diameter of the expansion hole 21 gradually increases along the flow direction of the slurry, the hole diameter of the reduced-diameter hole 23 gradually decreases along the flow direction of the slurry, and the maximum hole diameter of the reduced-diameter hole 23 and the maximum hole diameter of the reduced-diameter hole 23 are equal to the hole diameter of the equal-diameter hole 22.

[0028] 4. The particle size D50 of the finished product slurry obtained in this embodiment is 0.083 μm, the viscosity is 2384 mPa·s, the effective ingredient mass is 0.1% in the silicon system, and the test electrode sheet resistivity value is 109.22 Ω·cm. The pure silicon powder electrode sheet resistivity without adding conductive agent is >10000 Ω·cm.

[0029] Embodiment 2: A method for efficiently preparing single-walled carbon nanotube slurry is as follows: 1. Put 50 g of single-walled carbon nanotube powder, 150 g of PVDF powder, and 9.8 kg of NMP solvent into a dispersion tank.

[0030] 2. Disperse the motor at 4.5 kw, the emulsifying head rotor stator diameter is 120 mm, open the emulsification dispersion, adjust the speed to 12 krpm, and disperse for 3 h to obtain a single-walled carbon nanotube bundle slurry (the particle size D50 tested by a laser particle size analyzer is 198.1 μm); 3. In the microfluidic channel, a turbulent homogenization channel and a "Y" type homogenization channel are sequentially filled, the homogenization pressure is adjusted to 1500 bar, the slurry obtained in step 2 is placed in the microfluidic homogenizer feed tank, and the microfluidic homogenizer is turned on. Wait for the slurry in the microfluidic homogenizer feed tank to pass through the microfluidic homogenizer into the discharge tank, pour the slurry in the discharge tank into the feed tank, and make the slurry pass through the microfluidic homogenizer 6 times. 60 mesh screen, a uniform single-walled carbon nanotube slurry with a particle size D50 of 0.797 μm is obtained. Among them, the microfluidic turbulent channel is a first turbulent structure 1 and a second turbulent structure 2 connected in series, the first turbulent structure 1 includes a plurality of stepped holes 11 connected in series along the slurry flow direction and gradually decreasing in hole diameter; the second turbulent structure 2 includes an expansion hole 21, an equal diameter hole 22 and a reduced diameter hole 23 connected in series along the slurry flow direction; the hole diameter of the expansion hole 21 gradually increases along the slurry flow direction, the hole diameter of the reduced diameter hole 23 gradually decreases along the slurry flow direction, and the maximum hole diameter of the reduced diameter hole 23 and the maximum hole diameter of the reduced diameter hole 23 are equal to the hole diameter of the equal diameter hole 22.

[0031] 4. The particle size D50 of the finished product slurry obtained in this embodiment is 0.797 μm, the viscosity is 2480 mPa•s, and the effective ingredient mass is 0.1% in the ternary NCM523. The test electrode sheet resistivity value is 4.99 Ω•cm.

[0032] (Pure ternary NCM523 electrode sheet resistivity without adding conductive agent is >1000 Ω•cm) Example 3: A method for efficiently preparing single-walled carbon nanotube slurry, the specific steps are as follows: 1. Prepare single-walled carbon nanotube powder 20 g, PVP powder 80 g, and pure water 9.9 kg into a dispersion tank.

[0033] 2. The dispersion motor is 4.5 kw, the rotor and stator diameter of the emulsifying head is 120 mm, the emulsification dispersion is started, the rotating speed is adjusted to 12 krpm, and the dispersion is carried out for 2 h to obtain a single-walled carbon nanotube bundle slurry (the particle size D50 tested by laser particle size instrument is 342.5 μm); 3. In the microfluidic channel, a turbulent homogenization channel, a "Z" type homogenization channel and a "Y" type homogenization channel are sequentially loaded, the homogenization pressure is adjusted to 2000 bar, the slurry obtained in the second step is placed in the microfluidic homogenizer feed tank, and the microfluidic homogenizer is started. Wait for the slurry in the microfluidic homogenizer feed tank to pass through the microfluidic homogenizer into the discharge tank, pour the slurry in the discharge tank into the feed tank, and make the slurry pass through the microfluidic homogenizer repeatedly for 5 times, sieve through a 60 mesh screen, and obtain a uniform single-walled carbon nanotube slurry with a particle size D50 of 0.067 μm. Among them, the microfluidic turbulent channel is a first turbulent structure 1 and a second turbulent structure 2 connected in series, the first turbulent structure 1 includes a plurality of stepped holes 11 connected in sequence along the slurry flow direction and gradually decreasing in hole diameter; the second turbulent structure 2 includes an expansion hole 21, an equal-diameter hole 22 and a reduced-diameter hole 23 connected in sequence along the slurry flow direction; the hole diameter of the expansion hole 21 gradually increases along the slurry flow direction, the hole diameter of the reduced-diameter hole 23 gradually decreases along the slurry flow direction, and the maximum hole diameter of the reduced-diameter hole 23 and the maximum hole diameter of the reduced-diameter hole 23 are equal to the hole diameter of the equal-diameter hole 22.

[0034] 4. The particle size D50 of the finished product slurry obtained in this embodiment is 0.067 μm, the viscosity is 2837 mPa·s, and the effective ingredient is 0.1% in the silicon system. The test electrode sheet resistivity value is 211.67 Ω·cm.

[0035] Comparative Example 1: The specific steps are as follows: 1. Prepare single-walled carbon nanotube powder 40 g, CMC powder 60 g, and pure water 9.9 kg into a dispersion tank.

[0036] 2. The dispersion motor is 3 kw, the dispersion disc diameter is 100 mm, the high-speed dispersion is started, the rotating speed is adjusted to 1500 rpm, and the single-walled carbon nanotube bundle slurry is obtained after dispersion for 4 h.

[0037] 3. In the microfluidic channel, only a "Z" type homogenization channel is loaded, the homogenization pressure is adjusted to 1000 bar, the slurry obtained in the second step is placed in the microfluidic homogenizer feed tank, and the microfluidic homogenizer is started. Wait for the slurry in the microfluidic homogenizer feed tank to pass through the microfluidic homogenizer into the discharge tank, pour the slurry in the discharge tank into the feed tank, and make the slurry pass through the microfluidic homogenizer repeatedly for 5 times, sieve through a 60 mesh screen, and obtain a single-walled carbon nanotube slurry with a particle size D50 of 10.37 μm; the slurry continues to pass through the microfluidic homogenizer under the pressure of 1000 bar, the particle size of the slurry is tested for the 10th time, the particle size of the slurry is tested for the 15th time, and the particle size of the slurry is tested for the 20th time, 4. Take the homogeneous 5th and 20th slurry samples, and test the particle size D50 of the slurry as 10.37 μm and 4.899 μm, respectively, and the viscosity as 4596 mPa•s and 4373 mPa•s, respectively. Add 0.1% of the effective ingredient in the silicon system, and test the electrode sheet resistivity value as 1108.96 Ω•cm and 852.72 Ω•cm, respectively.

[0038] Comparative Example 2: The specific steps are as follows: 1. Put 40 g of single-walled carbon nanotube powder, 60 g of CMC powder, and 9.9 kg of pure water into a dispersion tank.

[0039] 2. Disperse the motor at 3 kw, and the dispersion disc diameter is 100 mm. Start high-speed dispersion, and adjust the rotation speed to 1500 rpm. Disperse for 4 h to obtain a single-walled carbon nanotube bundle slurry.

[0040] 3. In the microfluidic channel, only install the turbulent type homogenization channel (the structure is the same as that in Example 1), and adjust the homogenization pressure to 1000 bar. Put the slurry obtained in step 2 into the microfluidic homogenizer feed tank, and start the microfluidic homogenizer. Wait for the slurry in the microfluidic homogenizer feed tank to completely pass through the microfluidic homogenizer into the discharge tank. Pour the slurry in the discharge tank into the feed tank, so that the slurry repeatedly passes through the microfluidic homogenizer for 10 times, and sieve through a 60-mesh sieve to obtain a relatively uniform single-walled carbon nanotube slurry with a particle size D50 of 0.096 μm.

[0041] 4. Test the particle size D50 of the finished product slurry obtained in this example as 0.096 μm, and the viscosity as 2590 mPa•s. Add 0.1% of the effective ingredient in the silicon system, and test the electrode sheet resistivity value as 153.7 Ω•cm.

[0042] Comparative Example 3: The specific steps are as follows: 1. Put 40 g of single-walled carbon nanotube powder, 60 g of CMC powder, and 9.9 kg of pure water into a dispersion tank.

[0043] 2. Disperse the motor at 3 kw, and the dispersion disc diameter is 100 mm. Start high-speed dispersion, and adjust the rotation speed to 1500 rpm. Disperse for 4 h to obtain a single-walled carbon nanotube bundle slurry.

[0044] 3. In the microfluidic channel, sequentially install the “Z” type homogenization channel and the turbulent type homogenization channel (the structure is the same as that in Example 1), and adjust the homogenization pressure to 1000 bar. Put the slurry obtained in step 2 into the microfluidic homogenizer feed tank, and start the microfluidic homogenizer. Wait for the slurry in the microfluidic homogenizer feed tank to completely pass through the microfluidic homogenizer into the discharge tank. Pour the slurry in the discharge tank into the feed tank, so that the slurry repeatedly passes through the microfluidic homogenizer for 4 times, and sieve through a 60-mesh sieve to obtain a relatively uniform single-walled carbon nanotube slurry with a particle size D50 of 6.157 μm.

[0045] 4. The particle size D50 of the finished product slurry obtained in this example was 6.157 μm, and the viscosity was 4872 mPa-s. When added at 0.1% of the effective ingredient in a silicon system, the test electrode sheet resistivity value was 870.52 Ω-cm.

[0046] Comparative Example 4: The specific steps are as follows: 1. Prepare single-walled carbon nanotube powder 40 g, CMC powder 60 g, and pure water 9.9 kg into a dispersion tank.

[0047] 2. Disperse the motor at 3 kw, the dispersion disc diameter is 100 mm, start high-speed dispersion, adjust the speed to 1500 rpm, and disperse for 4 h to obtain a single-walled carbon nanotube bundle slurry; 3. Only install the "Z" type homogenizing channel in the micro-fluid channel, adjust the homogenizing pressure to 2500 bar, place the slurry obtained in step 2 into the micro-fluid homogenizer feed tank, and start the micro-fluid homogenizer. Wait for the slurry in the micro-fluid homogenizer feed tank to pass through the micro-fluid homogenizer into the discharge tank, pour the slurry in the discharge tank into the feed tank, and make the slurry pass through the micro-fluid homogenizer 12 times. Screened through a 60 mesh screen, a relatively uniform single-walled carbon nanotube slurry with a particle size D50 of 1.627 μm was obtained; 4. The particle size D50 of the finished product slurry obtained in this example was 1.627 μm, and the viscosity was 4144 mPa-s. When added at 0.1% of the effective ingredient in a silicon system, the test electrode sheet resistivity value was 622.77 Ω-cm.

[0048] Comparative Example 5: The specific steps are as follows: 1. Prepare single-walled carbon nanotube powder 40 g, CMC powder 60 g, and pure water 9.9 kg into a dispersion tank.

[0049] 2. Disperse the motor at 3 kw, the dispersion disc diameter is 100 mm, start high-speed dispersion, adjust the speed to 1500 rpm, and disperse for 4 h to obtain a single-walled carbon nanotube bundle slurry; 3. Use a conventional collision valve type homogenizing cavity to homogenize the slurry obtained in step 2. Adjust the homogenizing pressure to 1000 bar, place the slurry obtained in step 2 into the conventional homogenizer feed tank, and start the conventional homogenizer. Wait for the slurry in the conventional homogenizer feed tank to pass through the conventional homogenizer into the discharge tank, pour the slurry in the discharge tank into the feed tank, and make the slurry pass through the conventional homogenizer 10 times. Screened through a 60 mesh screen, a relatively uniform single-walled carbon nanotube slurry with a particle size D50 of 0.085 μm was obtained; 4. The particle size D50 of the finished product slurry obtained in this example was 0.085 μm, and the viscosity was 2128 mPa-s. When added at 0.1% of the effective ingredient in a silicon system, the test electrode sheet resistivity value was 1266.57 Ω-cm.

[0050] The above examples are only used to illustrate the technical solutions of the present application, but not to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those ordinarily skilled in the art should understand: the technical solutions recorded in the foregoing examples can still be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for efficiently producing a single-walled carbon nanotube paste, characterized by: The preparation steps are as follows: (1) feeding, placing single-walled carbon nanotube powder, dispersant, solvent in a stirring tank; (2) premixing, starting the stirring tank dispersion, and obtaining uniformly mixed carbon nanotube bundle slurry after stirring and dispersion; (3) micro-jet homogenization, passing the carbon nanotube bundle slurry obtained after premixing through a high-pressure micro-jet homogenizer multiple times, and obtaining uniform single carbon nanotube slurry after dispersion; the micro-jet homogenization channel combination is a combination of a turbulent type homogenization channel and a conventional type homogenization channel; the type of the conventional type homogenization channel is one or more of "Z" type, "Y" type, "H" type and "K" type; (4) sieving, obtaining single-walled carbon nanotube finished slurry.

2. The method of claim 1, wherein the method is characterized by: In step (1), the mass percentage of single-walled carbon nanotube powder is 0.1%-1%, the mass percentage of dispersant is 0.5%-1.5%, and the mass percentage of solvent is 97.5%-99.5%.

3. The process for dispersing single-walled carbon nanotube paste according to claim 1, wherein: In step (1), the dispersant is one of carboxymethyl cellulose, polyvinylidene fluoride and polyvinylpyrrolidone.

4. The method of claim 1, wherein the method is characterized by: In step (1), the solvent is one of NMP, pure water, ethanol and isopropanol.

5. The method of claim 1, wherein the method is characterized by: In step (2), the premixing dispersion in step (2) adopts emulsion dispersion or high-speed stirring dispersion; the high-speed stirring dispersion time is 2-10h, the high-speed stirring dispersion speed is 600rpm-3000rpm, and the dispersion disc diameter is 40mm-400mm; the emulsion dispersion time is 1-6h, the emulsion dispersion shear speed is 0.5krpm-20krpm, and the emulsion dispersion stator diameter is 40mm-350mm; the power of the emulsion motor or high-speed dispersion motor is 0.8kw-35kw.

6. The process for dispersing single-walled carbon nanotube paste according to claim 1, wherein: In step (3), the micro-jet turbulent channel includes a first turbulent structure and a second turbulent structure connected in series, or includes two first turbulent structures connected in series, or includes two second turbulent structures connected in series; The first turbulent structure includes a plurality of stepped holes connected in sequence along the slurry flow direction and gradually decreasing in hole diameter; the second turbulent structure includes an expansion hole, an equal-diameter hole and a reduced-diameter hole connected in sequence along the slurry flow direction; the hole diameter of the expansion hole gradually increases along the slurry flow direction, the hole diameter of the reduced-diameter hole gradually decreases along the slurry flow direction, and the maximum hole diameter of the reduced-diameter hole is equal to the hole diameter of the equal-diameter hole.

7. The method of claim 1, wherein the single-walled carbon nanotube paste is prepared with high efficiency. In step (3), the carbon nanotube bundle slurry obtained after premixing is first passed through a turbulent type homogenization channel and then passed through a conventional channel.

8. The method of claim 1, wherein the single-walled carbon nanotube paste is produced with high efficiency. In step (3), the number of channels connected in series of the high-pressure micro-jet homogenizer is 2-4.

9. The method of claim 1, wherein the single-walled carbon nanotube paste is prepared with high efficiency. The number of homogenization channels of the micro-jet homogenizer is 2-8, and the pressure of the micro-jet homogenizer is 500bar-2000bar.

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