A high-solids-content single-walled carbon nanotube slurry, its preparation method and application

Abstract

This application discloses a high-solids-content single-walled carbon nanotube slurry, its preparation method, and its application. The preparation method includes: Step 1, mixing a small-molecule dispersant and a solvent using ultrasonic dispersion to form a first solution; Step 2, mixing the first solution and single-walled carbon nanotubes using ultrasonic dispersion to form a second solution; Step 3, mixing the second solution and a polymer dispersant using ultrasonic dispersion to form a third solution; Step 4, dispersing the third solution using microfluidic high-pressure homogenization to obtain the high-solids-content single-walled carbon nanotube slurry. The preparation method of the single-walled carbon nanotube slurry provided by this application is green, environmentally friendly, low-cost, and highly efficient. The single-walled carbon nanotubes are orderly dispersed, and the viscosity is moderate, stable, and does not rebound. When used in positive or negative electrode slurries for lithium-ion batteries, it can significantly improve conductivity.

Description

Technical Field

[0001] This application relates to the field of battery materials technology, and in particular to a high-solids-content single-walled carbon nanotube slurry, its preparation method, and its application. Background Technology

[0002] Single-walled carbon nanotubes (SUVs) possess excellent electrical and thermal conductivity, exhibiting superior performance even at extremely low addition levels and significantly enhancing the mechanical properties of materials. However, due to their high specific surface area, large aspect ratio, and excellent crystal structure, SUVs exhibit poor solubility and dispersibility in various solvents, hindering the full utilization of their electrical conductivity and other properties. This is particularly challenging when preparing high-solids-content, uniform, and stable SUV conductive slurries.

[0003] Currently, the dispersion process of single-walled carbon nanotube slurries mostly relies on sand mills or high-pressure homogenizers, and the types of dispersants used are limited, resulting in problems such as difficulty in increasing solid content, poor viscosity stability (easily leading to high viscosity), poor dispersion effect, and unsatisfactory electrical conductivity. Summary of the Invention

[0004] Based on this, this application provides a high solids content single-walled carbon nanotube slurry and its preparation method. The single-walled carbon nanotube slurry has high solids content, stable viscosity, good dispersion effect, and excellent electrical conductivity.

[0005] A method for preparing a high-solids-content single-walled carbon nanotube slurry, comprising: Step 1: The small molecule dispersant and solvent are mixed by ultrasonic dispersion to form the first solution; Step 2: The first solution and single-walled carbon nanotubes are mixed by ultrasonic dispersion to form a second solution; Step 3: The second solution and the polymer dispersant are mixed by ultrasonic dispersion to form a third solution; Step 4: The third solution is dispersed using a microfluidic high-pressure homogenization method to obtain the high-solids-content single-walled carbon nanotube slurry.

[0006] In this application, the solvent and small molecule dispersant are first uniformly mixed using ultrasonic dispersion to form a first solution. Single-walled carbon nanotubes are then added to the first solution. The small molecule dispersant wets the single-walled carbon nanotubes, which helps to overcome the van der Waals forces (electrostatic forces) between the single-walled carbon nanotubes by utilizing the additional effects of ultrasonic cavitation, high-pressure microjets, and strong vibrations, thus effectively dispersing the single-walled carbon nanotubes. Then, a polymeric dispersant is added, which is uniformly adsorbed on the surface of the individual single-walled carbon nanotubes. Under the action of high-pressure homogenization by microjets, the single-walled carbon nanotubes maintain a stable spacing, thereby dispersing in the solvent, and the entire system is in a stable state.

[0007] Several alternative methods are provided below, but they are not intended as additional limitations on the overall solution above. They are merely further additions or optimizations. Provided there are no technical or logical contradictions, each alternative method can be combined individually with respect to the overall solution above, or multiple alternative methods can be combined with each other.

[0008] Optionally, the small molecule dispersant is at least one of the following: diamine maleate (CAS: 928-01-8), sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium 1-naphthalene sulfonate, bis(dodecyl)dimethylammonium bromide, hexadecyltrimethylammonium bromide, methyl hydrazine carbamate, alcohol ether phosphate, anhydrous piperazine, isopropanolamine, N-methyldiethanolamine, ethanolamine, and isobutanolamine.

[0009] Optionally, the polymer dispersant is at least one of polyvinyl alcohol, carboxymethyl cellulose, hydrogenated nitrile rubber, polyvinylpyrrolidone, styrene-maleic anhydride copolymer, hydroxyethyl cellulose, cellulose acetate, polyvinyl butyral, ethylene-vinyl alcohol copolymer, methacrylate-acrylate block copolymer, polyacrylic acid, and ethylene oxide-propylene oxide block copolymer.

[0010] The polymer dispersant has a weight-average molecular weight of 40,000 to 80,000. Preferably, the polymer dispersant has a weight-average molecular weight of 40,000 to 60,000.

[0011] Optionally, the solvent is water or an organic solvent, wherein the organic solvent is a polar solvent such as N-methylpyrrolidone (NMP) or dimethylformamide.

[0012] Optionally, the single-walled carbon nanotubes are purified single-walled carbon nanotubes.

[0013] Optionally, the weight ratio of the solvent, small molecule dispersant, polymer dispersant, and single-walled carbon nanotubes is (85~95.9):(0.1~2):(2~8):(2~5).

[0014] Optionally, the small molecule dispersant is dodecyltrimethylammonium bromide, and the polymer dispersant is polyvinylpyrrolidone.

[0015] Optionally, the small molecule dispersant is sodium dodecylbenzenesulfonate and isopropanolamine, with a mass ratio of sodium dodecylbenzenesulfonate to isopropanolamine of 1:1~2, and the polymer dispersant is hydrogenated nitrile butadiene rubber.

[0016] Optionally, the small molecule dispersant is methyl hydrazine formate and isobutanolamine, with a mass ratio of methyl hydrazine formate to isobutanolamine of 1:1 to 2, and the polymer dispersant is polyvinylpyrrolidone.

[0017] Optionally, the small molecule dispersant is sodium dodecylbenzenesulfonate and isobutanolamine, with a mass ratio of sodium dodecylbenzenesulfonate to isobutanolamine of 1 to 2:1, and the polymer dispersant is an ethylene-vinyl alcohol polymer.

[0018] Optionally, the small molecule dispersant is sodium dodecylbenzenesulfonate and N-methyldiethanolamine, with a mass ratio of sodium dodecylbenzenesulfonate to N-methyldiethanolamine of 1:1~2, and the polymer dispersant is polyvinylpyrrolidone.

[0019] Optionally, the small molecule dispersant is maleic diamine and anhydrous piperazine, with a mass ratio of maleic diamine and anhydrous piperazine of 1 to 2:1, and the polymer dispersant is styrene-maleic anhydride copolymer and hydrogenated nitrile butadiene rubber, with a mass ratio of styrene-maleic anhydride copolymer and hydrogenated nitrile butadiene rubber of 1:1 to 2.

[0020] Optionally, the small molecule dispersant is sodium 1-naphthalenesulfonate and isobutanolamine, with a mass ratio of sodium 1-naphthalenesulfonate and isobutanolamine of 1~2:1, and the polymer dispersant is polyvinylpyrrolidone and carboxymethyl cellulose, with a mass ratio of polyvinylpyrrolidone and carboxymethyl cellulose of 1~2:1.

[0021] Optionally, the small molecule dispersant is isopropanolamine and alcohol ether phosphate, with a mass ratio of isopropanolamine to alcohol ether phosphate of 1:1 to 2, and the polymer dispersant is polyvinyl alcohol and styrene-maleic anhydride copolymer, with a mass ratio of polyvinyl alcohol to styrene-maleic anhydride copolymer of 1:1 to 2.

[0022] Optionally, in step 1, the frequency of ultrasonic dispersion is 15~20KHz and the time is 10~20min.

[0023] Optionally, in step 2, the frequency of ultrasonic dispersion is 20~40KHz and the time is 0.5~2h.

[0024] Optionally, in step 3, the frequency of ultrasonic dispersion is 20~40KHz and the time is 0.5~2h.

[0025] Optionally, in step 4, the pressure of the microjet high-pressure homogenization is 1500~3000psi, and the time is 1~3h.

[0026] Optionally, the ultrasonic dispersion in step 2 is carried out at a temperature of 50~60℃.

[0027] Optionally, the ultrasonic dispersion in step 3 is carried out at a temperature of 50~60℃.

[0028] In the preparation method of high solids content single-walled carbon nanotube slurry provided in this application, the synergistic effect of small molecule dispersants and polymer dispersants is utilized to ensure that the single-walled carbon nanotubes in the slurry have good dispersibility, moderate viscosity, and can maintain viscosity stability.

[0029] This application also provides a high-solids-content single-walled carbon nanotube slurry, prepared by the aforementioned preparation method. The single-walled carbon nanotube slurry contains 1% to 2% by mass of single-walled carbon nanotubes, and has a viscosity of less than 10,000 mPa·s and a particle size of less than 40 µm.

[0030] This application also provides a lithium-ion battery in which the single-walled carbon nanotube slurry is added to the positive or negative electrode slurry of the lithium-ion battery.

[0031] This application employs a relatively mild ultrasonic dispersion method, which can preserve the structure of single-walled carbon nanotubes to the greatest extent. The single-walled carbon nanotubes are first wetted by a small molecule dispersant. At the same time, the cavitation effect of ultrasound, high-pressure microjets, and strong vibrations are used to disperse the single-walled carbon nanotube bundles into individual tubes. The polymer dispersant is adsorbed on the surface of the individual single-walled carbon nanotubes. Relying on the steric hindrance of the polymer dispersant, the single-walled carbon nanotubes maintain a stable dispersion state. Finally, high-pressure homogenization through microjets further disperses the single-walled carbon nanotubes more uniformly in the solvent.

[0032] The method for preparing single-walled carbon nanotube slurry provided in this application is green, environmentally friendly, low-cost, and highly efficient. The single-walled carbon nanotubes are dispersed in an orderly manner and have moderate, stable viscosity without rebound. When used in positive or negative electrode slurries for lithium-ion batteries, it can significantly improve conductivity. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating the preparation method of the high solids content single-walled carbon nanotube slurry of this application; Figure 2 The image shows the Raman spectrum of a single-walled carbon nanotube. Figure 3 This is a SEM image of the slurry after combining the single-walled carbon nanotube slurry with the cathode material in Example 6. Figure 4 SEM image of the slurry prepared in Example 8 after combining single-walled carbon nanotube slurry with silicon carbide material; Figure 5 SEM image of the slurry after combining the single-walled carbon nanotube slurry prepared in Comparative Example 1 with the cathode material; Figure 6 SEM image of the slurry prepared by combining single-walled carbon nanotube slurry with silicon carbon material in Comparative Example 2. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] Example 1 95.8 parts by weight of NMP (N-methylpyrrolidone, i.e., solvent) and 0.2 parts by weight of dodecyltrimethylammonium bromide (i.e., small molecule dispersant) were added to an ultrasonic dispersion device, the ultrasonic frequency was set to 15 Hz, and the ultrasonic dispersion time was 10 min to make the mixture uniform and obtain the first solution. 1.0 part by weight of single-walled carbon nanotubes was added to the first solution, and the ultrasonic frequency was set to 25 Hz, the ultrasonic dispersion time was 60 min, and the temperature was controlled at 55℃ to carry out ultrasonic dispersion to obtain the second solution. Take 3 parts by weight of polyvinylpyrrolidone (Xin Kaiyuan K30) (i.e. polymer dispersant) and add it to the second solution. Control the frequency at 20 Hz and continue to sonicate at 55 ℃ for 0.5 h to make the polyvinylpyrrolidone and single-walled carbon nanotubes fully mixed and uniformly adsorbed to obtain the third solution. The third solution was dispersed in an ultra-high pressure microfluidic homogenizer at 1800 psi for 2 h to obtain a high solids content single-walled carbon nanotube slurry. The viscosity of the high solids content single-walled carbon nanotube slurry was less than 8000 mpa.s and the particle size was less than 40 µm.

[0036] The prepared single-walled carbon nanotube slurry was combined with the cathode material, wherein the ratio of NCM cathode material to single-walled carbon nanotubes (the effective component of the single-walled carbon nanotube slurry) was 100:0.05. The resistivity of the prepared electrode was then tested.

[0037] Example 2 94.5 parts by weight of NMP (i.e., solvent), 0.2 parts by weight of sodium dodecylbenzenesulfonate (i.e., small molecule dispersant), and 0.3 parts by weight of isopropanolamine (i.e., small molecule dispersant) were added to an ultrasonic dispersion device. The ultrasonic frequency was set to 15 Hz and the ultrasonic dispersion time was 10 min to make the mixture uniform and obtain the first solution. 1.5 parts by weight of single-walled carbon nanotubes were added to the first solution, and the ultrasonic frequency was set to 35 Hz, the ultrasonic dispersion time was 1.5 h, and the temperature was controlled at 55 ℃ to carry out ultrasonic dispersion to obtain the second solution. Take 3.5 parts by weight of hydrogenated nitrile butadiene rubber (Ruion A760) (i.e. polymer dispersant) and add it to the second solution. Control the frequency at 40 Hz and continue to sonicate at 55 ℃ for 1 hour to make the hydrogenated nitrile butadiene rubber and single-walled carbon nanotubes fully mixed and uniformly adsorbed to obtain the third solution. The third solution was dispersed in an ultra-high pressure microfluidic homogenizer at 2500 psi for 2 h to obtain a high solids content single-walled carbon nanotube slurry. The viscosity of the high solids content single-walled carbon nanotube slurry was less than 6500 mpa.s and the particle size was less than 35 µm.

[0038] The prepared single-walled carbon nanotube slurry was combined with the cathode material, wherein the ratio of NCM cathode material to single-walled carbon nanotubes (the effective component of the single-walled carbon nanotube slurry) was 100:0.05. The resistivity of the prepared electrode was then tested.

[0039] Example 3 93.4 parts by weight of NMP, 0.3 parts by weight of methyl hydrazide and 0.3 parts by weight of isobutanolamine were added to an ultrasonic dispersion device, the ultrasonic frequency was set to 15 Hz and the ultrasonic dispersion time was 10 min. After mixing evenly, the first solution was obtained. 1.5 parts by weight of single-walled carbon nanotubes were added to the first solution, and the ultrasonic frequency was set to 35 Hz, the ultrasonic dispersion time was 1.5 h, and the temperature was controlled at 55 ℃ to carry out ultrasonic dispersion to obtain the second solution. Take 4.5 parts by weight of polyvinylpyrrolidone and add it to the second solution. Control the frequency at 40 Hz and continue to sonicate at 55 ℃ for 1 hour to make the polyvinylpyrrolidone and single-walled carbon nanotubes fully mixed and uniformly adsorbed to obtain the third solution. The third solution was dispersed in an ultra-high pressure microfluidic homogenizer at 2500 psi for 2 h to obtain a high solids content single-walled carbon nanotube slurry. The viscosity of the high solids content single-walled carbon nanotube slurry was less than 6000 mpa.s and the particle size was less than 40 µm.

[0040] The prepared single-walled carbon nanotube slurry was combined with the cathode material, wherein the ratio of NCM cathode material to single-walled carbon nanotubes (the effective component of the single-walled carbon nanotube slurry) was 100:0.05. The resistivity of the prepared electrode was then tested.

[0041] Example 4 92.3 parts by weight of NMP, 0.4 parts by weight of sodium dodecylbenzenesulfonate, and 0.3 parts by weight of isobutanolamine were added to an ultrasonic dispersion device. The ultrasonic frequency was set to 15 Hz and the ultrasonic dispersion time was 10 min to make the mixture uniform and obtain the first solution. Two parts by weight of single-walled carbon nanotubes were added to the first solution, and the ultrasonic frequency was set to 35 Hz, the ultrasonic dispersion time was 2 h, and the temperature was controlled at 55 ℃ to carry out ultrasonic dispersion to obtain the second solution. Five parts by weight of ethylene-vinyl alcohol polymer (Kuraray G156) were added to the second solution. The ultrasonic treatment was continued at 35 Hz and 55 ℃ for 2 hours to ensure that the ethylene-vinyl alcohol polymer and single-walled carbon nanotubes were fully mixed and uniformly adsorbed, thus obtaining the third solution. The third solution was dispersed in an ultra-high pressure microfluidic homogenizer at 2800 psi for 2 h to obtain a high solids content single-walled carbon nanotube slurry. The viscosity of the high solids content single-walled carbon nanotube slurry was less than 10000 mpa.s and the particle size was less than 35 µm.

[0042] The prepared single-walled carbon nanotube slurry was combined with the cathode material, wherein the ratio of cathode material to single-walled carbon nanotubes (the effective component of the single-walled carbon nanotube slurry) was 100:0.05. The resistivity of the prepared electrode was then tested.

[0043] Example 5 91.7 parts by weight of NMP, 0.4 parts by weight of sodium dodecylbenzenesulfonate and 0.4 parts by weight of N-methyldiethanolamine were added to an ultrasonic dispersion device. The ultrasonic frequency was set to 15 Hz and the ultrasonic dispersion time was 10 min to make the mixture uniform and obtain the first solution. Two parts by weight of single-walled carbon nanotubes were added to the first solution, and the ultrasonic frequency was set to 35 Hz, the ultrasonic dispersion time was 2 h, and the temperature was controlled at 55 ℃ to carry out ultrasonic dispersion to obtain the second solution. Take 5.5 parts by weight of polyvinylpyrrolidone and add it to the mixture of single-walled carbon nanotubes. Control the frequency at 35 Hz and the temperature at 55 ℃ and continue to sonicate for 2 hours to make the polyvinylpyrrolidone and single-walled carbon nanotubes fully mixed and uniformly adsorbed to obtain the third solution. The third solution was dispersed in an ultra-high pressure microfluidic homogenizer at 2800 psi for 2 h to obtain a high solids content single-walled carbon nanotube slurry. The viscosity of the high solids content single-walled carbon nanotube slurry was less than 9000 mpa.s and the particle size was less than 40 µm.

[0044] The prepared single-walled carbon nanotube slurry was combined with the cathode material, wherein the ratio of cathode material to single-walled carbon nanotubes (the effective component of the single-walled carbon nanotube slurry) was 100:0.05. The resistivity of the prepared electrode was then tested.

[0045] Example 6 92.5 parts by weight of NMP, 0.6 parts by weight of diamine maleate and 0.4 parts by weight of anhydrous piperazine were added to an ultrasonic dispersion device. The ultrasonic frequency was set to 15 Hz and the ultrasonic dispersion time was 10 min to make the mixture uniform and obtain the first solution. Two parts by weight of single-walled carbon nanotubes were added to the first solution, and the ultrasonic frequency was set to 35 Hz, the ultrasonic dispersion time was 2 h, and the temperature was controlled at 55 ℃ to carry out ultrasonic dispersion to obtain the second solution. Two parts by weight of styrene-maleic anhydride copolymer (BYK-2013) and 2.5 parts by weight of hydrogenated nitrile butadiene rubber (Rievon A760) were added to a single-walled carbon nanotube mixture. The mixture was ultrasonically treated at a frequency of 40 Hz and a temperature of 55 ℃ for 2 hours to ensure that the styrene-maleic anhydride copolymer, hydrogenated nitrile butadiene rubber and single-walled carbon nanotubes were fully mixed and uniformly adsorbed to obtain a third solution. The third solution was dispersed in an ultra-high pressure microfluidic homogenizer at 3000 psi for 2.5 h to obtain a high solids content single-walled carbon nanotube slurry. The viscosity of the high solids content single-walled carbon nanotube slurry was less than 7000 mpa.s and the particle size was less than 30 µm.

[0046] The prepared single-walled carbon nanotube slurry was combined with the cathode material, wherein the ratio of cathode material to single-walled carbon nanotubes (the effective component of the single-walled carbon nanotube slurry) was 100:0.05. The resistivity of the prepared electrode was then tested.

[0047] Example 7 Add 94.5 parts by weight of deionized water, 0.6 parts by weight of sodium 1-naphthalenesulfonate, and 0.4 parts by weight of isobutanolamine to an ultrasonic dispersion device, set the ultrasonic frequency to 15 Hz, and the ultrasonic dispersion time to 10 min to mix evenly and obtain the first solution. Two parts by weight of single-walled carbon nanotubes were added to the first solution, and the ultrasonic frequency was set to 35 Hz, the ultrasonic dispersion time was 2 h, and the temperature was controlled at 55 ℃ to carry out ultrasonic dispersion to obtain the second solution. Take 1.5 parts by weight of polyvinylpyrrolidone and 1 part by weight of low molecular weight carboxymethyl cellulose (Mn 3w-5w) and add them to the single-walled carbon nanotube mixture. Control the frequency at 40Hz and continue to sonicate at 55℃ for 2h to make the polyvinylpyrrolidone, low molecular weight carboxymethyl cellulose and single-walled carbon nanotubes fully mixed and uniformly adsorbed to obtain the third solution. The third solution was dispersed in an ultra-high pressure microfluidic homogenizer at 2800 psi for 2.5 h to obtain a high solids content single-walled carbon nanotube slurry. The viscosity of the high solids content single-walled carbon nanotube slurry was less than 8000 mpa.s and the particle size was less than 40 µm.

[0048] The prepared single-walled carbon nanotube slurry was combined with silicon-carbon anode material, wherein the ratio of silicon-carbon anode material to single-walled carbon nanotubes (the effective component of the single-walled carbon nanotube slurry) was 100:0.1. The resistivity of the prepared electrode was then tested.

[0049] Example 8 Add 94 parts by weight of deionized water, 0.5 parts by weight of isopropanolamine, and 0.5 parts by weight of alcohol ether phosphate (AEO-9P) to an ultrasonic dispersion device, set the ultrasonic frequency to 15 Hz, and the ultrasonic dispersion time to 10 min to mix evenly and obtain the first solution. Two parts by weight of single-walled carbon nanotubes were added to the first solution, and the ultrasonic frequency was set to 35 Hz, the ultrasonic dispersion time was 2 h, and the temperature was controlled at 55 ℃ to carry out ultrasonic dispersion to obtain the second solution. One part by weight of polyvinyl alcohol (DENKA DR-1137) and two parts by weight of styrene-maleic anhydride copolymer (BYK, Germany) were added to the second solution. The ultrasonic treatment was continued at a frequency of 40 Hz and a temperature of 55 ℃ for 2 hours to allow the polyvinyl alcohol and styrene-maleic anhydride copolymer to be fully mixed and uniformly adsorbed with the single-walled carbon nanotubes, thus obtaining the third solution. The third solution was dispersed in an ultra-high pressure microfluidic homogenizer at 3000 psi for 2.5 h to obtain a high solids content single-walled carbon nanotube slurry. The viscosity of the high solids content single-walled carbon nanotube slurry was less than 6000 mpa.s and the particle size was less than 40 µm.

[0050] The prepared single-walled carbon nanotube slurry was combined with silicon-carbon material, wherein the ratio of silicon-carbon material to single-walled carbon nanotubes (the effective component of the single-walled carbon nanotube slurry) was 100:0.1. Electrodes were then prepared and their resistivity was tested.

[0051] Comparative Example 1 97.6 parts by weight of NMP, 0.4 parts by weight of single-walled carbon nanotubes and 2 parts by weight of polyvinylidene fluoride (Arkema HSV900) were added to an emulsifier dispersion device and dispersed for 30 minutes to obtain a premixed single-walled carbon nanotube mixture. The premixed single-walled carbon nanotube mixture was then dispersed 15 times at 800 bar using a high-pressure homogenizer to obtain a single-walled carbon nanotube slurry. The viscosity of the single-walled carbon nanotube slurry was less than 3000 mPa·s and the particle size was less than 35 µm.

[0052] The prepared single-walled carbon nanotube slurry was combined with the cathode material, wherein the ratio of cathode material to single-walled carbon nanotubes (the effective component of the single-walled carbon nanotube slurry) was 100:0.1. The resistivity of the prepared electrode was then tested.

[0053] Comparative Example 2 99 parts by weight of NMP, 0.4 parts by weight of single-walled carbon nanotubes and 0.6 parts by weight of carboxymethyl cellulose (DAICEL 1110) were added to an emulsifier dispersion device and dispersed for 30 minutes to obtain a premixed single-walled carbon nanotube mixture. The premixed single-walled carbon nanotube mixture was then dispersed 15 times at 800 bar using a high-pressure homogenizer to obtain a single-walled carbon nanotube slurry. The viscosity of the single-walled carbon nanotube slurry was less than 3000 mPa·s and the particle size was less than 35 µm.

[0054] The prepared single-walled carbon nanotube slurry was combined with silicon-carbon material, wherein the ratio of CVD silicon-carbon anode material to single-walled carbon nanotubes (the effective component of the single-walled carbon nanotube slurry) was 100:0.1. The resistivity of the prepared electrode was then tested.

[0055] Performance Characterization The test data of the above embodiments and comparative slurries are shown in Table 1 below.

[0056] Table 1

[0057] See Figure 2 The Raman spectrum shows that the G / D ratio of the single-walled carbon nanotube is 90.2, indicating that the single-walled carbon nanotube has high crystallinity, few defects, and good electrochemical performance.

[0058] See Figure 3 As shown in the SEM image of the slurry after the single-walled carbon nanotube slurry and the cathode material are combined in Example 6, the single-walled carbon nanotubes are tightly coated on the surface of the cathode material, forming a rich conductive network and improving the conductivity of the electrode.

[0059] See Figure 4 As shown in the SEM image of the slurry prepared in Example 8 and the silicon-carbon material, the single-walled carbon nanotubes are uniformly distributed on the surface of the silicon-carbon anode material, which improves the conductivity.

[0060] See Figure 5 As shown in the SEM image of the slurry prepared in Comparative Example 1 after combining with the cathode material, the single-walled carbon nanotubes are wrapped around the surface of the cathode material. The single-walled carbon nanotubes are more often wrapped around the surface of the main material in the form of single-walled carbon nanotube bundles, and the conductive network is relatively concentrated, which affects electron transfer.

[0061] See Figure 6 As shown in the SEM image of the slurry prepared by Comparative Example 2 after combining the single-walled carbon nanotube slurry with silicon carbon material, the single-walled carbon nanotubes are mostly wrapped around the surface of the main material in the form of single-walled carbon nanotube bundles. The conductive network is too concentrated, which affects electron transfer.

[0062] 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.

[0063] The embodiments described above are merely illustrative of several implementation methods of this application, 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 this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a high solid content single-walled carbon nanotube paste, characterized by, include: Step 1: The small molecule dispersant and solvent are mixed by ultrasonic dispersion to form the first solution; Step 2: The first solution and single-walled carbon nanotubes are mixed by ultrasonic dispersion to form a second solution; Step 3: The second solution and the polymer dispersant are mixed by ultrasonic dispersion to form a third solution; Step 4: The third solution is dispersed using microfluidic high-pressure homogenization to obtain the high-solids-content single-walled carbon nanotube slurry. The weight ratio of the solvent, small molecule dispersant, polymer dispersant, and single-walled carbon nanotubes is (85~95.9):(0.1~2):(2~8):(2~5). The small molecule dispersant is at least one of the following: diamine maleate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium 1-naphthalene sulfonate, dodecyltrimethylammonium bromide, bis(dodecyl)dimethylammonium bromide, hexadecyltrimethylammonium bromide, methyl hydrazine carbamate, alcohol ether phosphate, anhydrous piperazine, isopropanolamine, N-methyldiethanolamine, ethanolamine, and isobutanolamine.

2. The method for preparing the high-solids-content single-walled carbon nanotube slurry as described in claim 1, characterized in that, The polymer dispersant is at least one of polyvinyl alcohol, carboxymethyl cellulose, hydrogenated nitrile butadiene rubber, polyvinylpyrrolidone, styrene-maleic anhydride copolymer, hydroxyethyl cellulose, cellulose acetate, polyvinyl butyral, ethylene-vinyl alcohol copolymer, methacrylic acid-acrylate block copolymer, polyacrylic acid, and ethylene oxide-propylene oxide block copolymer.

3. The method for preparing the high-solids-content single-walled carbon nanotube slurry as described in claim 1, characterized in that, In step 1, the frequency of ultrasonic dispersion is 15~20KHz, and the time is 10~20min.

4. The method for preparing the high-solids-content single-walled carbon nanotube slurry as described in claim 1, characterized in that, In step 2, the frequency of ultrasonic dispersion is 20~40KHz, and the time is 0.5~2h.

5. The method for preparing the high-solids-content single-walled carbon nanotube slurry as described in claim 1, characterized in that, In step 3, the frequency of ultrasonic dispersion is 20~40KHz, and the time is 0.5~2h.

6. The method for preparing the high-solids-content single-walled carbon nanotube slurry as described in claim 1, characterized in that, In step 4, the pressure for microjet high-pressure homogenization is 1500~3000psi, and the time is 1~3h.

7. A high-solids-content single-walled carbon nanotube slurry, characterized in that, The single-walled carbon nanotube slurry is prepared by any one of the preparation methods described in claims 1 to 6. The mass fraction of single-walled carbon nanotubes in the slurry is 1% to 2%, and the viscosity of the high-solids-content single-walled carbon nanotube slurry is less than 10000 mPa·s, and the particle size is less than 40 µm.

8. A lithium-ion battery, characterized in that, Add the single-walled carbon nanotube slurry as described in claim 7 to the positive or negative electrode slurry of a lithium-ion battery.

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