Highly-dispersible, highly-conductive, high-purity single-walled carbon nanotube material and method of making

Abstract

The application discloses an easily-dispersed high-conductivity high-purity single-wall carbon nanotube material and a preparation method thereof, relates to the technical field of single-wall carbon nanotube material preparation, and comprises the following steps: mixing single-wall carbon nanotube crude pipes with a nitrogen source, performing a reaction in a tube furnace to obtain carbon pipe intermediate product 1; mixing the carbon pipe intermediate product 1 with a dispersing agent, then mixing the carbon pipe intermediate product 1 with a solvent, performing emulsification, and performing suction filtration to obtain carbon pipe intermediate product 2; mixing the carbon pipe intermediate product 2 with mixed acid to perform a reaction, and performing cleaning and drying to obtain a final product. The single-wall carbon nanotube crude pipes are mixed with a nitrogen-containing nonmetal compound nitrogen source, compressed air is introduced to perform a reaction, and then dispersion and mixed acid treatment are sequentially performed, so that the effect of effectively removing amorphous carbon impurities and metal catalyst impurities is achieved, and the problem that, due to insufficient purity of existing carbon pipes, when the carbon pipes are used as conductive additives to prepare electrode materials, the uniformity of an electrode conductive network cannot be guaranteed, and then the overall electrochemical performance of the electrode is affected can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of single-walled carbon nanotube material preparation, in particular to an easily dispersed high-conductive high-purity single-walled carbon nanotube material and a preparation method thereof. BACKGROUND

[0002] The preparation method of the carbon nanotube material synthesizes carbon nanotubes with specific structures and properties by controlling the reaction conditions, and the function is to provide a basis for the application of carbon nanotubes in the fields of electronic devices, energy storage materials, composite materials and sensors, etc. By adjusting the preparation process, the key characteristics of carbon nanotubes such as conductivity, mechanical strength and adsorption capacity can be optimized to meet the performance requirements of different scenarios.

[0003] In the prior art, the preparation method of the carbon nanotube material has the problems of insufficient purity, poor dispersibility, affected conductivity and low yield in the preparation process, which makes it difficult to form a uniform conductive network when applied in the fields of electronic devices and energy storage materials, and limits the electrochemical performance and stability, and also causes resource waste and cost increase. Based on this, the present application provides an easily dispersed high-conductive high-purity carbon nanotube material and a preparation method thereof. SUMMARY

[0004] The purpose of the present application is to provide an easily dispersed high-conductive high-purity single-walled carbon nanotube material and a preparation method thereof. The present application mixes single-walled carbon nanotube crude tubes with nitrogen-containing non-metallic compound nitrogen sources and reacts in a tube furnace by introducing compressed air, combines dispersant emulsification homogenization and mixed acid treatment, and through the synergistic effect of optimizing process parameters such as nitrogen source ratio, reaction temperature, compressed air flow, emulsification time and mixed acid conditions, effectively removes amorphous carbon and metal catalyst impurities, and improves the purity, dispersibility, conductivity and yield of carbon nanotubes.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0006] A preparation method of an easily dispersed high-conductive high-purity single-walled carbon nanotube material, comprising the following steps:

[0007] Mixing single-walled carbon nanotube crude tubes with nitrogen-containing non-metallic compound nitrogen sources and reacting in a tube furnace, introducing compressed air at a flow rate of 50-2000 mL / min during heating at 150-450℃, and obtaining carbon tube intermediate product 1 through the interaction of nitrogen elements and single-walled carbon nanotubes;

[0008] Mixing the carbon tube intermediate product 1 with a dispersant, then mixing with a solvent, emulsifying and homogenizing for 2-12h, and then filtering to obtain carbon tube intermediate product 2;

[0009] The carbon tube intermediate product 2 is mixed with mixed acid, the solid content of the prepared mixture is controlled in the interval of 0.5% to 2.5%, the reaction is carried out at 45°C to 95°C for 2h to 12h, and the final product is obtained after cleaning and drying.

[0010] Preferably, the nitrogen source is one or more of melamine, dicyandiamide, polydopamine and NH4Cl.

[0011] Preferably, the mass ratio of the single-walled carbon nanotube crude tube to the nitrogen source is (5:1) to (1:3).

[0012] Preferably, the reaction in the tube furnace is carried out in an atmospheric environment.

[0013] The oxidation time is 0.5 to 8h.

[0014] Preferably, the dispersant is one or more of C8-16 alkyl glucoside, sodium carboxymethyl cellulose, polyvinylpyrrolidone, sodium polyacrylate, and cetyltrimethylammonium bromide.

[0015] Preferably, the mass ratio of the dispersant to the single-walled carbon nanotube crude tube is (1:5) to (1:100).

[0016] The solvent is one or more of high-purity deionized water or ethanol, and the solid-liquid ratio of the solid mixture to the solvent is (1:30) to (1:3000).

[0017] Preferably, the mixed acid is one or more of hydrochloric acid, dilute sulfuric acid, dilute nitric acid, hydrofluoric acid, citric acid and oxalic acid.

[0018] Preferably, the mass ratio of the carbon tube intermediate product 2, the mixed acid and the high-purity deionized water is (1:2:5) to (1:30:30).

[0019] Preferably, the Raman spectrum IG / ID value of the final product is ≥49, and the yield of the carbon tube intermediate product 1 is ≥92%.

[0020] According to the formula The water-based conductive paste is prepared with a mass ratio of 0.4%:0.4%:99.2%, and the viscosity is tested by a DVPLLV viscometer, which is ≤2955cp.

[0021] According to the formula The mass ratio of the conductive paste is 95.5%:1.5%:1.5%:1.4%:0.1%, and the electrode conductivity is tested by a BER2500 electrode resistance meter, and the electrode conductivity is ≥297S / m when the thickness of the electrode active material is 50 to 70μm.

[0022] Preferably, the easily dispersible high-conductivity high-purity single-walled carbon nanotube material is prepared by an easily dispersible high-conductivity high-purity single-walled carbon nanotube material preparation method, the material purity is greater than or equal to 98.5%, and the residual amount of metal catalyst is less than or equal to 650 ppm.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] 1. The present application realizes the effect of effectively removing amorphous carbon impurities and metal catalyst impurities by mixing single-walled carbon nanotube crude pipes with nitrogen-containing non-metallic compound nitrogen sources, introducing compressed air at a specific temperature, and then sequentially performing dispersion and mixed acid treatment. Compared with the prior art, the purity of the carbon pipes can be improved, thereby solving the problem that the existing carbon pipes cannot guarantee the uniformity of the electrode conductive network when used as conductive additives to prepare electrode materials, thereby affecting the overall electrochemical performance of the electrode.

[0025] 2. The present application realizes the effect of reducing the residual amount of metal catalyst in the carbon pipes to the level of 650 ppm by using a dispersant to emulsify the single-walled carbon nanotube crude pipes, fully exposing more metal catalyst impurities wrapped in amorphous carbon, and then using mixed acid to fully remove the metal catalyst impurities. Compared with the prior art, the purity of the carbon pipes can be improved, thereby solving the problem that the high residual amount of metal catalyst in the existing carbon pipes adversely affects the electrical properties and stability.

[0026] 3. The present application realizes the effect of high yield of carbon pipe intermediate product 1 by using a low-temperature oxidation process to promote the oxidation of part of the amorphous carbon impurities, in combination with the proportion of dispersant and solvent and the reaction conditions. Compared with the prior art, the material utilization rate during the preparation of the carbon pipes can be further improved, and the loss of the carbon pipes can be significantly reduced, thereby solving the problem of low yield of the existing carbon pipe preparation method, which causes resource waste and cost increase. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] The present embodiment provides a preparation method of an easily dispersible high-conductivity high-purity single-walled carbon nanotube material, comprising the following steps:

[0029] The single-walled carbon nanotube crude tube is mixed with a nitrogen-containing non-metallic compound nitrogen source, a reaction is carried out in a tube furnace, compressed air is introduced at a flow rate of 500 mL / min during heating at 300°C, and the oxidation time is 4 h, so that the carbon nanotube intermediate product 1 is obtained through the interaction of nitrogen and the single-walled carbon nanotube;

[0030] The carbon nanotube intermediate product 1 is mixed with 0.5 g of sodium carboxymethyl cellulose, and then mixed with 750 g of water, emulsified and homogenized for 2 h, and then suction filtered to obtain the carbon nanotube intermediate product 2;

[0031] The carbon nanotube intermediate product 2 is mixed with mixed acid, the mixed acid is composed of dilute hydrochloric acid, dilute nitric acid and hydrofluoric acid, and the specific ratio is intermediate product 2:dilute hydrochloric acid:dilute nitric acid:hydrofluoric acid:water = 1:8:17:10:35, the solid content of the prepared mixture is controlled to be 1.408%, and the reaction is carried out at 60°C for 6 h, and the final product is obtained after washing and drying.

[0032] In some embodiments, the nitrogen source is one or more of melamine, dicyandiamide, polydopamine and NH4Cl.

[0033] In some embodiments, the mass ratio of the single-walled carbon nanotube crude tube to the nitrogen source is (5:1) to (1:3).

[0034] In some embodiments, the reaction in the tube furnace is carried out in an atmospheric environment.

[0035] The oxidation time is 0.5 to 8 h.

[0036] In some embodiments, the dispersant is one or more of C8-16 alkyl glucoside, sodium carboxymethyl cellulose, polyvinylpyrrolidone, sodium polyacrylate and cetyltrimethylammonium bromide.

[0037] In some embodiments, the mass ratio of the dispersant to the single-walled carbon nanotube crude tube is (1:5) to (1:100).

[0038] The solvent is one or more of high-purity deionized water or ethanol, and the solid-liquid ratio of the solid mixture to the solvent is (1:30) to (1:3000).

[0039] In some embodiments, the mixed acid is one or more of hydrochloric acid, dilute sulfuric acid, dilute nitric acid, hydrofluoric acid, citric acid and oxalic acid.

[0040] In some embodiments, the mass ratio of the carbon nanotube intermediate product 2, the mixed acid and the high-purity deionized water is (1:2:5) to (1:30:30).

[0041] In some embodiments, the Raman spectrum IG / ID value of the final product is greater than or equal to 49, and the yield of the carbon nanotube intermediate product 1 is greater than or equal to 92%.

[0042] According to The water-based conductive paste with a mass ratio of 0.4%:0.4%:99.2% is tested by using a DVPLLV type viscometer, and the viscosity is ≤2955 cp;

[0043] The electrode paste is prepared according to a mass ratio of SiOx:CMC:SBR:SP:SWCNTs of 95.5%:1.5%:1.5%:1.4%:0.1%, and the electrode conductivity is tested by using a BER2500 electrode resistance meter. When the active material thickness of the electrode is 50-70 μm, the electrode conductivity is ≥297 S / m.

[0044] In some embodiments, a dispersible high-conductivity high-purity single-walled carbon nanotube material is prepared by a method for preparing a dispersible high-conductivity high-purity single-walled carbon nanotube material. The material has a purity of ≥98.5% and a residual amount of metal catalyst of ≤650 ppm.

[0045] Based on the foregoing embodiments, the following groups of experiments are performed:

[0046] It should be noted that the raw materials used in the following embodiments are commercially available.

[0047] In Example 1, a method for preparing a dispersible high-conductivity high-purity single-walled carbon nanotube material includes the following steps: 10 g of single-walled carbon nanotube crude tubes with a purity of 85.79% are mixed with 5 g of melamine, and the single-walled carbon nanotube crude tubes are reacted in a tube furnace. Compressed air is introduced at a flow rate of 50-2000 mL / min during heating at 150-450°C for 4 h. Through the interaction of nitrogen elements and single-walled carbon nanotubes, carbon tube intermediate product 1 is obtained.

[0048] The carbon tube intermediate product 1 is mixed with a dispersant, then mixed with a solvent, and emulsified and homogenized for 2-12 h, and then filtered to obtain carbon tube intermediate product 2.

[0049] The carbon tube intermediate product 2 is mixed with mixed acid, and the solid content of the prepared mixture is controlled in the range of 0.5%-2.5%. The mixture is reacted at 45-95°C for 2-12 h, and then washed and dried to obtain the final product.

[0050] In Example 2, a method for preparing a dispersible high-conductivity high-purity single-walled carbon nanotube material includes the following steps: 20 g of single-walled carbon nanotube crude tubes with a purity of 85.63% are mixed with 20 g of polydopamine, and the single-walled carbon nanotube crude tubes are reacted in a tube furnace. Compressed air is introduced at a flow rate of 2000 mL / min during heating at 150°C for 8 h. Through the interaction of nitrogen elements and single-walled carbon nanotubes, carbon tube intermediate product 1 is obtained.

[0051] The carbon tube intermediate product 1 is mixed with 0.2 g of hexadecyl trimethyl ammonium bromide, and then mixed with 660 g of ethanol, and then emulsified and homogenized for 5 h, and then filtered to obtain a carbon tube intermediate product 2;

[0052] The carbon tube intermediate product 2 is mixed with mixed acid, and the mixed acid is composed of dilute sulfuric acid, dilute nitric acid and hydrofluoric acid, and the specific ratio is intermediate product 2:dilute sulfuric acid:dilute nitric acid:hydrofluoric acid:water = 1:12:10:5:25, and the solid content of the prepared mixture is controlled to be 1.887%, and the mixture is reacted at 95°C for 7.5 h, and then washed and dried to obtain a final product.

[0053] Example Three, a preparation method of a high-conductivity and high-purity single-walled carbon nanotube material easy to disperse, comprising the following steps: The single-walled carbon nanotube crude tube with a purity of 82.77% is mixed with powder, and the mixture is reacted in a tube furnace, compressed air is introduced at a flow rate of 1000 mL / min during heating at 400°C, and the oxidation time is 4 h, and the carbon tube intermediate product 1 is obtained through the interaction between nitrogen element and single-walled carbon nanotubes.

[0054] The carbon tube intermediate product 1 is mixed with 0.3 g of polyvinylpyrrolidone, and then mixed with 7500 g of high-purity deionized water, and then emulsified and homogenized for 2 h, and then filtered to obtain a carbon tube intermediate product 2.

[0055] The carbon tube intermediate product 2 is mixed with mixed acid, and the mixed acid is composed of dilute hydrochloric acid, dilute nitric acid, oxalic acid and hydrofluoric acid, and the specific ratio is intermediate product 2:dilute hydrochloric acid:dilute nitric acid:oxalic acid:hydrofluoric acid:water = 1:10:10:5:7:15, and the solid content of the prepared mixture is controlled to be 2.083%, and the mixture is reacted at 75°C for 6 h, and then washed and dried to obtain a final product.

[0056] Example Four, a preparation method of a high-conductivity and high-purity single-walled carbon nanotube material easy to disperse, comprising the following steps:

[0057] The carbon tube intermediate product 1 is mixed with 0.286 g of polyacrylic acid sodium, and then mixed with 20000 g of ethanol, and then emulsified and homogenized for 4 h, and then filtered to obtain a carbon tube intermediate product 2.

[0058] The carbon tube intermediate product 2 is mixed with mixed acid composed of dilute hydrochloric acid, dilute nitric acid, oxalic acid and citric acid, and the specific ratio is intermediate product 2:dilute hydrochloric acid:dilute nitric acid:oxalic acid: citric acid:water = 1:5:8:5:5:30, the solid content of the prepared mixture is controlled to be 1.852%, and the reaction is carried out at 75°C for 2h, and the final product is obtained after cleaning and drying.

[0059] In example five, a preparation method of the easily dispersed high-conductive high-purity single-walled carbon nanotube material includes the following steps: 20g of single-walled carbon nanotube crude tubes with a purity of 85.28% are mixed with 40g of melamine, the reaction is carried out in a tube furnace, compressed air is introduced at a flow rate of 1000mL / min during heating at 350°C, and the oxidation time is 2h, and the carbon tube intermediate product 1 is obtained through the interaction between nitrogen element and single-walled carbon nanotubes.

[0060] The carbon tube intermediate product 1 is mixed with 0.667g of sodium carboxymethyl cellulose, and then mixed with 60000g of high-purity deionized water, emulsified and homogenized for 4h, and then suction filtered to obtain the carbon tube intermediate product 2.

[0061] The carbon tube intermediate product 2 is mixed with mixed acid composed of nitric acid and citric acid, and the specific ratio is intermediate product 2:nitric acid: citric acid:water = 1:15:10:20, the solid content of the prepared mixture is controlled to be 2.174%, and the reaction is carried out at 60°C for 12h, and the final product is obtained after cleaning and drying.

[0062] In example six, a preparation method of the easily dispersed high-conductive high-purity single-walled carbon nanotube material includes the following steps: 15g of single-walled carbon nanotube crude tubes with a purity of 83.66% are mixed with The reaction is carried out in a tube furnace, compressed air is introduced at a flow rate of 100mL / min during heating at 450°C, and the oxidation time is 0.5h, and the carbon tube intermediate product 1 is obtained through the interaction between nitrogen element and single-walled carbon nanotubes.

[0063] The carbon tube intermediate product 1 is mixed with 0.15g of polyvinylpyrrolidone, and then mixed with 1000g of ethanol, emulsified and homogenized for 2h, and then suction filtered to obtain the carbon tube intermediate product 2.

[0064] The carbon tube intermediate product 2 is mixed with mixed acid composed of dilute hydrochloric acid and dilute nitric acid, and the specific ratio is intermediate product 2:dilute hydrochloric acid:dilute nitric acid:water = 1:12:10:27, the solid content of the prepared mixture is controlled to be 2.000%, and the reaction is carried out at 75°C for 4h, and the final product is obtained after cleaning and drying.

[0065] Example Seven, a method for preparing a high-purity single-walled carbon nanotube material with high conductivity and easy dispersion, comprising the following steps: mixing 15 g of single-walled carbon nanotube crude tubes with 15 g of polydopamine, the purity of the single-walled carbon nanotube crude tubes being 84.16%, performing a reaction in a tube furnace, passing compressed air at a flow rate of 500 mL / min during heating at 400°C, and oxidizing for 2 h, to obtain carbon tube intermediate product 1 through the interaction of nitrogen elements with the single-walled carbon nanotubes;

[0066] Mixing the carbon tube intermediate product 1 with 3 g of sodium polyacrylate and then with 37500 g of high-purity deionized water, homogenizing for 3 h after emulsification, and then performing suction filtration to obtain carbon tube intermediate product 2;

[0067] Mixing the carbon tube intermediate product 2 with mixed acid, the mixed acid being composed of citric acid, dilute nitric acid, and hydrofluoric acid, the specific ratio being intermediate product 2: citric acid: dilute nitric acid: hydrofluoric acid: water = 1:5:15:4:15, controlling the solid content of the prepared mixture to be 2.500%, and reacting at 45°C for 6 h to obtain the final product after washing and drying.

[0068] Example Eight, a method for preparing a high-purity single-walled carbon nanotube material with high conductivity and easy dispersion, comprising the following steps: mixing 20 g of single-walled carbon nanotube crude tubes with 5 g of melamine, the purity of the single-walled carbon nanotube crude tubes being 85.22%, performing a reaction in a tube furnace, passing compressed air at a flow rate of 50 mL / min during heating at 200°C, and oxidizing for 6 h to obtain carbon tube intermediate product 1 through the interaction of nitrogen elements with the single-walled carbon nanotubes;

[0069] Mixing the carbon tube intermediate product 1 with 0.4 g of cetyltrimethylammonium bromide and then with 20000 g of ethanol, homogenizing for 5 h after emulsification, and then performing suction filtration to obtain carbon tube intermediate product 2;

[0070] Mixing the carbon tube intermediate product 2 with mixed acid, the mixed acid being composed of oxalic acid, dilute nitric acid, and hydrofluoric acid, the specific ratio being intermediate product 2: oxalic acid: dilute nitric acid: hydrofluoric acid: water = 1:5:12:8:20, controlling the solid content of the prepared mixture to be 2.174%, and reacting at 95°C for 10 h to obtain the final product after washing and drying.

[0071] Example Nine, a method for preparing a high-purity single-walled carbon nanotube material with high conductivity and easy dispersion, comprising the following steps: performing a reaction in a tube furnace on 20 g of single-walled carbon nanotube crude tubes, the purity of the single-walled carbon nanotube crude tubes being 84.95%, without a nitrogen source, passing compressed air at a flow rate of 1500 mL / min during heating at 350°C to obtain carbon tube intermediate product 1;

[0072] The carbon nanotube intermediate product 1 is mixed with 0.2 g of C8-16 alkyl glucoside, and then mixed with 1000 g of high-purity deionized water. After emulsification and homogenization for 12 h, the product is filtered to obtain carbon nanotube intermediate product 2.

[0073] The carbon nanotube intermediate product 2 is mixed with mixed acid, which is composed of dilute hydrochloric acid, dilute nitric acid and hydrofluoric acid. The specific ratio is intermediate product 2:dilute hydrochloric acid:dilute nitric acid:hydrofluoric acid:water = 1:12:12:4:27. The solid content of the prepared mixture is controlled at 1.786%, and the reaction is carried out at 50°C for 8 h. After washing and drying, the final product is obtained.

[0074] Comparative Example 1. The difference between this comparative example and Example 1 is that melamine is not added during the reaction, and the other steps are the same as in Example 1.

[0075] Comparative Example 2. The difference between this comparative example and Example 1 is that the emulsification and homogenization time is 1 h, and the other steps are the same as in Example 1.

[0076] Comparative Example 3. The difference between this comparative example and Example 1 is that the reaction temperature for mixing the carbon nanotube intermediate product 2 with the mixed acid is 40°C, and the other steps are the same as in Example 1.

[0077] Comparative Example 4. The difference between this comparative example and Example 1 is that the compressed air flow is 40 mL / min, and the other steps are the same as in Example 1.

[0078] Performance test: The single-walled carbon nanotube materials treated in Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, Example 8, Example 9, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 are subjected to performance testing. In the performance test, the purity test uses the national standard ash test, the Fe element content test uses ICP-OES test, the Raman test is carried out according to the conventional method, the yield of carbon nanotube intermediate product 1 is calculated by the mass of the product and the mass of the carbon nanotubes in the raw material, the viscosity test uses a DVPLLV type viscometer with a 64 rotor, a rotation speed of 60 rpm / min, a time of 30 s, and a pole conductivity test uses a BER2500 pole resistance meter with a pole active material thickness of 50-70 μm.

[0079] The Raman test IG / ID result of the commercial single-walled carbon nanotube is 35.62, the viscosity of the commercial single-walled carbon nanotube conductive paste is 4583 cp, and the pole conductivity of the commercial single-walled carbon nanotube conductive paste is 233.581 S / m.

[0080] The test data obtained are recorded in Table 1 below:

[0081]

[0082] The performance test results show that the performance of each of the embodiment one is excellent, which indicates that under the process parameters, by adding melamine as a nitrogen source, impurities can be effectively removed, the purity, dispersibility and conductivity of the single-walled carbon nanotubes are improved, and the feasibility of the basic process of the application is verified.

[0083] In the embodiment two, polydopamine is used as a nitrogen source, under lower temperature and high compressed air flow, high-purity and low-metal-residual single-walled carbon nanotubes can still be obtained, and the yield of carbon tube intermediate 1 is higher, which indicates that the process of the application can still play a role stably under different nitrogen sources and a wider range of process parameters.

[0084] In the embodiment three, the is used as a nitrogen source, under higher temperature and medium compressed air flow, the purity and structural integrity of the single-walled carbon nanotubes are outstanding, the slurry viscosity is lower, and the dispersibility is good, which indicates that the combination of a specific nitrogen source and process parameters can further optimize the performance of the product.

[0085] In the embodiment four, dicyandiamide is used as a nitrogen source, under a certain temperature for a shorter time, the yield of carbon tube intermediate 1 is higher and the sheet conductivity is significantly improved, which indicates that the process of the application can effectively enhance the conductivity of the single-walled carbon nanotubes while ensuring the yield, and is suitable for scenarios with higher requirements for conductivity.

[0086] In the embodiment five, melamine is used as a nitrogen source, under the condition of a large solid-liquid ratio, high-purity and low-metal-residual products can still be obtained, which indicates that the process of the application is still effective when the solvent usage is large, and provides a reference for the selection of solvent usage in large-scale production.

[0087] In the embodiment six, the is used as a nitrogen source, under higher temperature and shorter heating time, the performance of the product can still meet the requirements, which reflects the stability of the process of the application under high temperature and short time treatment, and is beneficial to improve the production efficiency.

[0088] In the embodiment seven, polydopamine is used as a nitrogen source, and the mass ratio of dispersant to carbon tube crude pipe is small, under lower reaction temperature, the performance of the product is good, which indicates that even if the amount of dispersant is relatively large, the process of the application can still play a role effectively, and provides flexibility for the adjustment of the amount of dispersant.

[0089] In the embodiment eight, melamine is used as a nitrogen source, under lower temperature and low compressed air flow, the slurry viscosity is lower and the dispersibility is outstanding, which indicates that the process of the application can still ensure the good dispersibility of the single-walled carbon nanotubes under low compressed air flow, and widens the applicable range of process parameters.

[0090] The product has high purity and performance under the condition of no nitrogen source and suitable process parameters, which shows that the other process steps of the application can improve the performance of single-walled carbon nanotubes to some extent even without nitrogen source, and also highlights that the addition of nitrogen source can further optimize the performance.

[0091] The performance of Comparative Example 1 is significantly worse than that of Example 1 without adding nitrogen source, which shows that the addition of nitrogen source plays a key role in improving the purity of single-walled carbon nanotubes, reducing metal residues, improving structural integrity, dispersibility and conductivity, and verifies the importance of nitrogen source in the process of the application.

[0092] The performance of Comparative Example 2 is reduced due to the shorter emulsification and homogenization time than that of Example 1, which shows that sufficient emulsification and homogenization time is an important factor to ensure the sufficient exposure of metal catalyst impurities and improve the subsequent treatment effect, and shows the rationality of the emulsification and homogenization time parameter in the application.

[0093] The performance of Comparative Example 3 is poor due to the lower reaction temperature than that of Example 1, which shows that suitable reaction temperature is a necessary condition to ensure the sufficient removal of impurities by mixed acid, and reflects the importance of the reaction temperature parameter in the application.

[0094] The performance of Comparative Example 4 is not good due to the lower compressed air flow than that of Example 1, which shows that suitable compressed air flow is helpful to promote the oxidation of amorphous carbon impurities, and verifies the rationality of the compressed air flow parameter in the application.

[0095] Through comparison and analysis of the related data in the table, it can be seen that the purity, dispersibility and conductivity of single-walled carbon nanotube material are significantly improved by the synergistic effect of reasonable selection of nitrogen source type and ratio, optimization of tube furnace reaction temperature and time, control of compressed air flow, adjustment of dispersant and solvent amount, setting of suitable emulsification and homogenization time and mixed acid reaction conditions, while ensuring high yield of carbon nanotube intermediate 1, effectively solving the problems of insufficient purity of carbon nanotube, high metal residue, poor dispersibility and low yield in the prior art. Therefore, the preparation method of the easy-to-disperse high-conductivity high-purity carbon nanotube material provided by the application has a wider market prospect and is more suitable for promotion.

[0096] In the description of the present specification, the description of the terms "one experiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the experiment or example are included in at least one experiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same experiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more experiments or examples in a suitable manner.

[0097] The above-disclosed preferred experiments are merely intended to help illustrate the application. The preferred experiments do not describe all the details of the application, nor limit the application to the specific embodiments described. It will be apparent to one of ordinary skill in the art that many modifications and variations can be made to the experiments described herein. The experiments are selected and described in order to best explain the principles of the application and practical applications, to thereby enable others skilled in the art to best utilize the application. The application is only limited by the claims and their full scope and equivalents.

Claims

1. A method for preparing easily dispersible, highly conductive, and high-purity single-walled carbon nanotube material, characterized in that, Includes the following steps: Single-walled carbon nanotubes were mixed with a nitrogen source of a nitrogen-containing non-metallic compound and reacted in a tube furnace. Compressed air was introduced at a flow rate of 50–2000 mL / min during heating at 150–450 °C. Through the interaction between nitrogen and single-walled carbon nanotubes, carbon nanotube intermediate product 1 was obtained. The nitrogen source is one or more of melamine, dicyandiamide, polydopamine, and NH4Cl; The mass ratio of the single-walled carbon nanotube thick tube to the nitrogen source is (5:1) to (1:3). The reaction in the tubular furnace is carried out under atmospheric pressure. The oxidation time is 0.5–8 hours; Carbon nanotube intermediate product 1 was mixed with a dispersant and then with a solvent. After emulsification and homogenization for 2-12 hours, the mixture was filtered to obtain carbon nanotube intermediate product 2. The dispersant is one or more of C8-16 alkyl glucoside, sodium carboxymethyl cellulose, polyvinylpyrrolidone, sodium polyacrylate, and hexadecyltrimethylammonium bromide; Carbon nanotube intermediate product 2 was mixed with mixed acid, and the solid content of the mixture was controlled in the range of 0.5% to 2.5%. The mixture was reacted at 45℃ to 95℃ for 2h to 12h. After washing and drying, the final product was obtained. The final product has a Raman IG / ID value ≥ 49, and the yield of carbon nanotube intermediate 1 is ≥ 92%. A water-based conductive paste was prepared with a SWCNTs:CMC:H2O mass ratio of 0.4%:0.4%:99.2%, and its viscosity was tested using a DVPLLV viscometer and found to be ≤2955cp. Electrode paste was prepared according to the mass ratio of SiOx:CMC:SBR:SP:SWCNTs conductive paste of 95.5%:1.5%:1.5%:1.4%:0.1%. The electrode conductivity was tested using a BER2500 electrode resistance meter. When the thickness of the active material of the electrode was 50-70 μm, the electrode conductivity was ≥297 S / m.

2. The method for preparing an easily dispersible, highly conductive, and high-purity single-walled carbon nanotube material according to claim 1, characterized in that: The mass ratio of the dispersant to the single-walled carbon nanotube coarse tube is (1:5) to (1:100). The solvent is one or more of high-purity deionized water or ethanol, and the solid-liquid ratio of the solid mixture to the solvent is (1:30) to (1:3000).

3. The method for preparing an easily dispersible, highly conductive, and high-purity single-walled carbon nanotube material according to claim 1, characterized in that: The mixed acid is a combination of hydrochloric acid, dilute sulfuric acid, dilute nitric acid, hydrofluoric acid, citric acid, and oxalic acid.

4. The method for preparing an easily dispersible, highly conductive, and high-purity single-walled carbon nanotube material according to claim 1, characterized in that: The mass ratio of the carbon nanotube intermediate product 2, mixed acid and high-purity deionized water is (1:2:5) to (1:30:30).

5. A readily dispersible, highly conductive, high-purity single-walled carbon nanotube material, characterized in that, The easily dispersible, highly conductive, and high-purity single-walled carbon nanotube material is prepared by the preparation method of the easily dispersible, highly conductive, and high-purity single-walled carbon nanotube material according to any one of claims 1-4, with a material purity ≥98.5% and a metal catalyst residue ≤650ppm.

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