Graphene aqueous slurry and preparation method thereof

Abstract

The invention belongs to the technical field of graphene slurry, and particularly relates to graphene aqueous slurry and a preparation method thereof. The graphene composite material is prepared by sequentially performing sulfhydrylation treatment and molecular bridging treatment on the graphene powder and finally performing click reaction, and the graphene aqueous slurry is prepared by matching acetylene black and a dispersing agent, so that the conductivity of the slurry is effectively improved, a relatively high Zeta potential absolute value is obtained, and good system stability is ensured.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of graphene slurry, and particularly relates to a graphene aqueous slurry and a preparation method thereof. BACKGROUND

[0002] With the rapid development of electronic information industry, the demand for conductive slurry in various fields such as aviation, chemical industry, printing and construction is increasing, and the requirements for the performance of the slurry are also increasing. Developing new, environmentally friendly and high-performance slurry is the development trend. Carbon-based materials are ubiquitous in nature and have excellent physical and chemical properties, which has attracted extensive research by scholars. Using carbon-based conductive phase to prepare aqueous slurry not only can expand the application of conductive slurry and improve its performance, but also meets the green and environmental protection concept. Graphene aqueous slurry is a kind of aqueous dispersion prepared by physical or chemical methods with graphene as the core raw material. It combines the excellent performance of graphene (such as high conductivity, high thermal conductivity, strong mechanical strength, etc.) with the environmental advantages of aqueous system, and is widely used in new energy, electronics, environmental protection, coating and other fields.

[0003] A preparation method of an electromagnetic shielding coating aqueous graphene slurry is disclosed in Chinese patent (publication number CN112126268B). The invention forms an active carbon layer on the surface of graphene powder by chemical treatment, and grows ferriferrous oxide nanoparticles on the surface of graphene, forming pretreated graphene. The prepared aqueous graphene slurry for electromagnetic shielding coating can solve the problem of uneven addition of graphene powder, reduce the cost of adding additives to the coating, and improve the electromagnetic shielding performance of the coating by compounding with nano ferrite. However, the existing graphene aqueous slurry has the problems of insufficient conductivity and poor system stability, which affects its further application.

[0004] Therefore, how to screen the components of graphene aqueous slurry, modify graphene, and cooperate with other functional components to effectively improve the conductivity of graphene aqueous slurry while ensuring good system stability has become a direction that needs to be focused on. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a graphene aqueous slurry and a preparation method thereof. The graphene powder is sequentially subjected to mercapto treatment and molecular bridging treatment, and then a graphene composite material is prepared by click reaction. The graphene aqueous slurry is prepared by cooperating with acetylene black and a dispersing agent, which effectively improves the conductivity of the slurry, obtains a higher absolute value of Zeta potential, and ensures good system stability.

[0006] The technical scheme adopted by the present application to solve the above technical problems is as follows: The first aspect of the present application provides a graphene aqueous slurry, comprising the following components in parts by weight: 4-6 parts of graphene composite material, 0.6-1.2 parts of acetylene black, 0.2-0.4 parts of dispersant, and 90-100 parts of deionized water.

[0007] As a preferred solution, the graphene composite material in the present application can be 4 parts, 4.5 parts, 5 parts, 5.5 parts or 6 parts, etc.

[0008] As a preferred solution, the acetylene black in the present application can be 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1.0 parts, 1.1 parts or 1.2 parts, etc.

[0009] As a preferred solution, the dispersant in the present application can be 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts or 0.4 parts, etc.

[0010] As a preferred solution, the preparation method of the graphene composite material comprises: first, performing mercapto treatment on graphene powder to obtain mercapto graphene; then, performing molecular bridging treatment on the mercapto graphene to obtain silver-containing mercapto graphene; and then, performing click reaction on the silver-containing mercapto graphene and carbon nanotubes to obtain the graphene composite material.

[0011] As a preferred solution, the step of mercapto treatment comprises: dispersing 0.8-1.6 parts of graphene powder in 180-200 parts of deionized water to obtain a graphene dispersion liquid; under ice bath conditions, uniformly mixing 1.2-1.6 parts of 1-2 mol / L hydrochloric acid solution, 1.1-1.5 parts of β-mercaptoethylamine and 0.8-1.2 parts of sodium nitrite in 10-12 parts of deionized water, and then adding 180-200 parts of the graphene dispersion liquid under ice bath conditions and stirring for 100-120 min; filtering, washing with water and drying to obtain mercapto graphene.

[0012] As a preferred solution, the step of molecular bridging treatment comprises: dissolving 1.8-2.2 parts of silver nitrate in 80-100 parts of deionized water, and then adding 0.5-0.7 parts of sodium hydroxide to obtain a silver-ammonia solution; adding 4-6 parts of glucose and 0.4-0.6 parts of potassium sodium tartrate to a mixture of 10-20 parts of deionized water and 80-90 parts of anhydrous ethanol, and then uniformly dispersing 0.8-1.6 parts of mercapto graphene, and then adding 80-100 parts of the silver-ammonia solution and stirring for 120-140 min; centrifuging, washing with water and vacuum drying to obtain silver-containing mercapto graphene.

[0013] As a preferred scheme, the step of the click reaction comprises: dispersing 2-4 parts of carbon nanotubes in 280-300 parts of N,N-dimethylformamide, then adding 4-6 parts of silver-containing mercapto graphene and 1.2-1.6 parts of dicumyl peroxide, stirring under a nitrogen atmosphere at 150-160℃ for 20-24h, centrifuging, washing with water, and drying to obtain the graphene composite material.

[0014] The graphene composite material of the present application is first subjected to mercapto treatment on the graphene powder using β-mercaptoethylamine to form mercapto groups on the graphene surface, then part of the mercapto groups are bridged with silver ammine solution to connect silver to the graphene through the mercapto groups, and finally the graphene surface unreacted mercapto groups and the double bonds on the carbon nanotubes are subjected to click reaction to prepare the graphene composite material containing silver and carbon nanotubes.

[0015] As a preferred scheme, the acetylene black is modified acetylene black. The preparation method of the modified acetylene black comprises: first subjecting commercially available acetylene black to acid treatment to obtain acidified acetylene black; then subjecting the acidified acetylene black to silane coupling agent treatment to obtain silane-coupled acetylene black; and finally subjecting the silane-coupled acetylene black to modification treatment using 2-acrylamido-2-methylpropanesulfonic acid to obtain the modified acetylene black.

[0016] As a preferred scheme, the step of acid treatment comprises: adding 0.6-1.2 parts of commercially available acetylene black to 40-50 parts of 3mol / L nitric acid solution, heating at 80-90℃ for 100-120min, washing with water to neutral, and drying to obtain the acidified acetylene black.

[0017] As a preferred scheme, the step of silane coupling agent treatment comprises: dispersing 0.6-1.2 parts of acidified acetylene black in 40-50 parts of anhydrous ethanol, adding 4-6 parts of ammonia water and ultrasonically stirring for 10-20min, adding 3-5 parts of silane coupling agent KH-570 under nitrogen protection, stirring at 50-60℃ for 8-10h, washing with water, filtering, and vacuum drying to obtain the silane-coupled acetylene black.

[0018] As a preferred scheme, the step of modification treatment comprises: adding 0.6-1.2 parts of silane-coupled acetylene black to 40-50 parts of N,N-dimethylformamide and ultrasonically dispersing for 10-20min, adding 0.6-1.2 parts of 2-acrylamido-2-methylpropanesulfonic acid and 0.02-0.04 parts of 2,2'-azobisisobutyronitrile under a nitrogen atmosphere, heating to 80-90℃ and stirring for 6-8h, washing with water, centrifuging, and drying to obtain the modified acetylene black.

[0019] The modified acetylene black of the present application firstly introduces oxygen-containing functional groups such as hydroxyl and carboxyl through acidification treatment to enhance the reactivity, then introduces double bonds to the surface of the acetylene black through KH-570 in an ethanol environment, and finally grafts 2-acrylamido-2-methylpropanesulfonic acid to obtain the modified acetylene black containing sulfonic acid groups.

[0020] As a preferred solution, the dispersant is selected from polyethylene glycol or polyvinylpyrrolidone.

[0021] In the second aspect of the present application, a preparation method of the graphene aqueous slurry according to the first aspect is provided, including the following steps: 4-6 parts of the graphene composite material, 0.6-1.2 parts of acetylene black and 0.2-0.4 parts of the dispersant are dispersed in 90-100 parts of deionized water, and then grinded for 4-6 hours to obtain the graphene aqueous slurry.

[0022] Compared with the prior art, the present application has the following beneficial effects: (1) The graphene composite material of the present application realizes molecular bridging through the sulfur element of the mercapto group. The graphene provides high electrical conductivity and large specific surface area, and serves as a main material to construct a conductive network. The carbon nanotube can enhance the conductive path and fill the gap between the graphene layers to form a three-dimensional conductive skeleton. The silver can fill the micropores or surface defects to reduce the contact resistance and improve the overall conductivity. The three components synergistically improve the conductivity of the aqueous slurry. (2) The sulfonic acid group introduced by the modified acetylene black of the present application provides an ionic conductive path, and forms a double path with the intrinsic electronic conduction of acetylene black, further optimizing the conductive network of acetylene black, reducing the contact resistance and improving the electrical conductivity. The 2-acrylamido-2-methylpropanesulfonic acid serves as a good dispersant for the graphene aqueous slurry, and the Zeta potential is significantly negatively shifted through the ionization of the sulfonic acid group, and the high absolute value of the Zeta potential realizes stable dispersion through electrostatic repulsion. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present application, the present application is illustrated as follows. It should be understood by those skilled in the art that the examples are only used to help understand the present application, and should not be regarded as a specific limitation on the present application.

[0024] Some components in the examples and comparative examples are as follows: Commercially available graphene powder, product number G992594, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; β-mercaptoethylamine, CAS number 60-23-1, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; Sodium nitrite, CAS number 7632-00-0, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.; Silver nitrate, CAS No. 7761-88-8, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; Glucose, CAS No. 50-99-7, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.; Potassium sodium tartrate, CAS No. 6381-59-5, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.; Diisopropyl peroxydicarbonate, CAS No. 80-43-3, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.; Carbon nanotubes, item number C121262, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Commercially available acetylene black, item number 141502, purchased from Shanghai Kolamann Reagent Co., Ltd.; Silane coupling agent KH-570, CAS No. 2530-85-0, purchased from Zhongshan Dixin Chemical Co., Ltd.; 2-Acrylamido-2-methylpropanesulfonic acid, CAS No. 15214-89-8, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.; 2,2'-Azobisisobutyronitrile, CAS No. 78-67-1, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; Polyethylene glycol, item number P103718, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Polyvinylpyrrolidone, item number P110608, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0025] Example 1, the embodiment provides a preparation method of graphene aqueous slurry, comprising the following steps: 6 parts of graphene composite material, 1.2 parts of modified acetylene black and 0.4 parts of dispersant polyethylene glycol are dispersed in 100 parts of deionized water, then ground for 6h, to obtain graphene aqueous slurry.

[0026] Preparation of the graphene composite material: 1.6 parts of graphene powder was dispersed in 200 parts of deionized water to obtain a graphene dispersion liquid; 1.6 parts of 2 mol / L hydrochloric acid solution, 1.5 parts of β-mercaptoethylamine and 1.2 parts of sodium nitrite were added to 12 parts of deionized water and mixed uniformly, and then 200 parts of the graphene dispersion liquid was added and stirred under ice bath conditions for 120 min; filtration, water washing and drying were performed to obtain mercapto-functionalized graphene; 2.2 parts of silver nitrate was dissolved in 100 parts of deionized water, and then 0.7 parts of sodium hydroxide was added and mixed uniformly to obtain a silver-ammonia solution; 6 parts of glucose, 0.6 parts of potassium sodium tartrate were added to a mixture of 20 parts of deionized water and 80 parts of anhydrous ethanol, and then 1.6 parts of mercapto-functionalized graphene was uniformly dispersed, and 100 parts of the silver-ammonia solution was added and stirred for 140 min; centrifugation, water washing and vacuum drying were performed to obtain silver-containing mercapto-functionalized graphene; 4 parts of carbon nanotubes were dispersed in 300 parts of N,N-dimethylformamide, and then 6 parts of silver-containing mercapto-functionalized graphene and 1.6 parts of dicumyl peroxide were added; stirring was performed under a nitrogen atmosphere at 160℃ for 20 h; centrifugation, water washing and drying were performed to obtain the graphene composite material.

[0027] Preparation of the modified acetylene black: 1.2 parts of commercially available acetylene black was added to 50 parts of 3 mol / L nitric acid solution, heated at 90℃ for 100 min, washed with water until neutral, and dried to obtain acidified acetylene black; 1.2 parts of the acidified acetylene black was dispersed in 50 parts of anhydrous ethanol, 6 parts of ammonia water was added and ultrasonically stirred for 20 min, 5 parts of silane coupling agent KH-570 was added under nitrogen protection, and stirring was performed at 60℃ for 8 h; water washing, filtration and vacuum drying were performed to obtain silane-coupled acetylene black; 1.2 parts of the silane-coupled acetylene black was ultrasonically dispersed in 50 parts of N,N-dimethylformamide for 20 min, 1.2 parts of 2-acrylamido-2-methylpropanesulfonic acid and 0.04 parts of 2,2'-azobis(isobutyronitrile) were added under a nitrogen atmosphere, the temperature was increased to 90℃, and stirring was performed for 6 h; water washing, centrifugation and drying were performed to obtain the modified acetylene black.

[0028] Embodiment 2, the embodiment provides a preparation method of a graphene aqueous slurry, including the following steps: 4 parts of the graphene composite material, 0.6 parts of the modified acetylene black and 0.2 parts of the dispersant polyvinylpyrrolidone were dispersed in 90 parts of deionized water, and then grinding was performed for 4 h to obtain the graphene aqueous slurry.

[0029] Preparation of the graphene composite material: 0.8 parts by weight of graphene powder were dispersed in 180 parts of deionized water to obtain a graphene dispersion. Under ice bath conditions, 1.2 parts of 1 mol / L hydrochloric acid solution, 1.1 parts of β-mercaptoethylamine, and 0.8 parts of sodium nitrite were added to 10 parts of deionized water and mixed evenly. Then, 180 parts of the graphene dispersion were added and stirred for 100 min under ice bath conditions. The mixture was filtered, washed with water, and dried to obtain mercaptographene. 1.8 parts of silver nitrate were dissolved in 80 parts of deionized water, and then 0.5 parts of sodium hydroxide were added and mixed evenly to obtain a silver ammonia solution. Four parts of glucose and 0.4 parts of potassium sodium tartrate were added to a mixture of 10 parts of deionized water and 90 parts of anhydrous ethanol. Then, 0.8 parts of mercaptographene were added and dispersed evenly. Next, 80 parts of the silver ammonia solution were added and stirred for 120 min. The mixture was centrifuged, washed with water, and vacuum dried to obtain silver-containing mercaptographene. Two parts of carbon nanotubes were dispersed in 280 parts of N,N-dimethylformamide. Then, four parts of silver-containing mercaptographene and 1.2 parts of dicumyl peroxide were added. The mixture was placed under a nitrogen atmosphere and stirred at 150 °C for 24 h. After centrifugation, washing with water, and drying, the graphene composite material was obtained.

[0030] Preparation of modified acetylene black: 0.6 parts by weight of commercially available acetylene black were added to 40 parts of 3 mol / L nitric acid solution, heated at 80℃ for 120 min, washed with water until neutral, and dried to obtain acidified acetylene black; 0.6 parts of acidified acetylene black were dispersed in 40 parts of anhydrous ethanol, 4 parts of ammonia water were added and ultrasonically stirred for 10 min, 3 parts of silane coupling agent KH-570 were added under nitrogen protection, stirred at 50℃ for 10 h, washed with water, filtered, and vacuum dried to obtain silane-coupled acetylene black; 0.6 parts of silane-coupled acetylene black were added to 40 parts of N,N-dimethylformamide and ultrasonically dispersed for 10 min, 0.6 parts of 2-acrylamido-2-methylpropanesulfonic acid and 0.02 parts of 2,2'-azobisisobutyronitrile were added under nitrogen atmosphere, heated to 80℃ and stirred for 8 h, washed with water, centrifuged, and dried to obtain modified acetylene black.

[0031] Example 3: This example provides a method for preparing a graphene aqueous slurry, including the following steps: Five parts of graphene composite material, 0.9 parts of modified acetylene black, and 0.4 parts of dispersant polyethylene glycol were dispersed in 95 parts of deionized water and then ground for 5 hours to obtain a graphene aqueous slurry.

[0032] Preparation of the graphene composite material: 1.2 parts by weight of graphene powder were dispersed in 190 parts of deionized water to obtain a graphene dispersion. Under ice bath conditions, 1.4 parts of 1.5 mol / L hydrochloric acid solution, 1.3 parts of β-mercaptoethylamine, and 0.9 parts of sodium nitrite were added to 11 parts of deionized water and mixed thoroughly. Then, 190 parts of the graphene dispersion were added and stirred for 110 min under ice bath conditions. The mixture was filtered, washed with water, and dried to obtain mercaptographene. 1.9 parts of silver nitrate were dissolved in 90 parts of deionized water, and then 0.6 parts of sodium hydroxide were added and mixed thoroughly to obtain a silver ammonia solution. Five parts of glucose and 0.5 parts of potassium sodium tartrate were added to a mixture of 15 parts of deionized water and 85 parts of anhydrous ethanol. Then, 1.2 parts of mercaptographene were added and dispersed evenly. Next, 90 parts of the silver ammonia solution were added and stirred for 130 min. The mixture was centrifuged, washed with water, and vacuum dried to obtain silver-containing mercaptographene. Three parts of carbon nanotubes were dispersed in 290 parts of N,N-dimethylformamide. Then, five parts of silver-containing mercaptographene and 1.4 parts of dicumyl peroxide were added. The mixture was placed under a nitrogen atmosphere and stirred at 155 °C for 22 h. After centrifugation, washing with water, and drying, the graphene composite material was obtained.

[0033] Preparation of modified acetylene black: 0.9 parts by weight of commercially available acetylene black were added to 45 parts of 3 mol / L nitric acid solution, heated at 85℃ for 110 min, washed with water until neutral, and dried to obtain acidified acetylene black; 0.9 parts of acidified acetylene black were dispersed in 45 parts of anhydrous ethanol, 5 parts of ammonia water were added and ultrasonically stirred for 15 min, 4 parts of silane coupling agent KH-570 were added under nitrogen protection, stirred at 55℃ for 9 h, washed with water, filtered, and vacuum dried to obtain silane-coupled acetylene black; 0.9 parts of silane-coupled acetylene black were added to 45 parts of N,N-dimethylformamide and ultrasonically dispersed for 15 min, 0.9 parts of 2-acrylamido-2-methylpropanesulfonic acid and 0.03 parts of 2,2'-azobisisobutyronitrile were added under nitrogen atmosphere, heated to 85℃ and stirred for 7 h, washed with water, centrifuged, and dried to obtain modified acetylene black.

[0034] Comparative Example 1 The difference between this comparative example and Example 1 is that commercially available graphene powder (item number G992594) was used instead of the graphene composite material, and commercially available acetylene black (item number 141502) was used instead of the modified acetylene black.

[0035] Comparative Example 2 The difference between this comparative example and Comparative Example 1 is that modified acetylene black was used instead of commercially available acetylene black (item number 141502).

[0036] Comparative Example 3 The difference between this comparative example and Comparative Example 1 is that a graphene composite material was used instead of commercially available graphene powder (item number G992594).

[0037] The performance of the graphene aqueous slurry provided in the above embodiments and comparative examples was tested using the following methods: (1) Conductivity test: After drying the graphene aqueous slurry, it was pressed into a disc with a diameter of 25.4 mm. The resistivity was then measured using a SX1934 (SZ-82) four-probe instrument, and the conductivity was calculated. (2) Zeta potential test: The graphene aqueous slurry was tested using a Zeta potential meter. The test solvent was deionized water with a concentration of 0.2 mg / mL and a pH value of 7. The more charge the dispersed particles in the slurry carry on the surface, the higher the absolute value of the measured Zeta potential and the more stable the system.

[0038] The performance test data are shown in Table 1. Table 1 Performance Test Results .

[0039] As can be seen from the above, the present invention prepares graphene composite material by sequentially performing mercaptolation treatment and molecular bridging treatment on graphene powder, and finally by click reaction. Combined with acetylene black and dispersant, graphene aqueous slurry (Examples 1 to 3) is prepared, which has the best comprehensive performance.

[0040] Compared to Example 1, replacing the graphene composite material with commercially available graphene powder (item number G992594) and replacing the modified acetylene black with commercially available acetylene black (item number 141502) resulted in decreased electrical conductivity and worse system stability (Comparative Example 1); replacing commercially available acetylene black (item number 141502) with modified acetylene black resulted in increased electrical conductivity and better system stability (Comparative Example 2); replacing commercially available graphene powder (item number G992594) with graphene composite material resulted in increased electrical conductivity (Comparative Example 3).

Claims

1. A graphene-based aqueous slurry, characterized in that, By weight, it comprises the following components: 4-6 parts graphene composite material, 0.6-1.2 parts acetylene black, 0.2-0.4 parts dispersant, and 90-100 parts deionized water; The preparation method of the graphene composite material includes: first, treating graphene powder with mercapto to obtain mercapto graphene; then, treating the mercapto graphene with molecular bridging to obtain silver-containing mercapto graphene; and then, performing a click reaction between the silver-containing mercapto graphene and carbon nanotubes to obtain the graphene composite material.

2. The graphene aqueous slurry according to claim 1, characterized in that, The steps of the thiolization treatment include: dispersing 0.8-1.6 parts by weight of graphene powder in 180-200 parts by weight of deionized water to obtain a graphene dispersion; adding 1.2-1.6 parts by weight of 1-2 mol / L hydrochloric acid solution, 1.1-1.5 parts by weight of β-mercaptoethylamine and 0.8-1.2 parts by weight of sodium nitrite to 10-12 parts by weight of deionized water under ice bath conditions and mixing evenly; then adding 180-200 parts by weight of graphene dispersion and stirring under ice bath conditions for 100-120 min; filtering, washing with water, and drying to obtain thiolized graphene.

3. The graphene aqueous slurry according to claim 1, characterized in that, The molecular bridging treatment steps include: dissolving 1.8-2.2 parts of silver nitrate in 80-100 parts of deionized water, then adding 0.5-0.7 parts of sodium hydroxide and mixing evenly to obtain a silver ammonia solution; adding 4-6 parts of glucose and 0.4-0.6 parts of potassium sodium tartrate to a mixture of 10-20 parts of deionized water and 80-90 parts of anhydrous ethanol, then adding 0.8-1.6 parts of mercaptographene and dispersing evenly, then adding 80-100 parts of the silver ammonia solution and stirring for 120-140 minutes, centrifuging, washing with water, and vacuum drying to obtain silver-containing mercaptographene.

4. The graphene aqueous slurry according to claim 1, characterized in that, The click reaction steps include: dispersing 2-4 parts of carbon nanotubes in 280-300 parts of N,N-dimethylformamide, then adding 4-6 parts of silver-containing mercaptographene and 1.2-1.6 parts of dicumyl peroxide, placing it under a nitrogen atmosphere, stirring at 150-160°C for 20-24 hours, centrifuging, washing with water, and drying to obtain a graphene composite material.

5. The graphene aqueous slurry according to claim 1, characterized in that, The acetylene black is a modified acetylene black; The method for preparing the modified acetylene black includes: first, acidifying commercially available acetylene black to obtain acidified acetylene black; then, treating the acidified acetylene black with a silane coupling agent to obtain silane-coupled acetylene black. Finally, silane-coupled acetylene black was modified using 2-acrylamido-2-methylpropanesulfonic acid to obtain modified acetylene black.

6. The graphene aqueous slurry according to claim 5, characterized in that, The acidification process includes: adding 0.6 to 1.2 parts by weight of commercially available acetylene black to 40 to 50 parts by weight of 3 mol / L nitric acid solution, heating at 80 to 90°C for 100 to 120 minutes, washing with water until neutral, and drying to obtain acidified acetylene black.

7. The graphene aqueous slurry according to claim 5, characterized in that, The steps of the silane coupling agent treatment include: dispersing 0.6-1.2 parts of acidified acetylene black in 40-50 parts of anhydrous ethanol, adding 4-6 parts of ammonia water and ultrasonically stirring for 10-20 minutes, adding 3-5 parts of silane coupling agent KH-570 under nitrogen protection, stirring at 50-60°C for 8-10 hours, washing with water, filtering, and vacuum drying to obtain silane-coupled acetylene black.

8. The graphene aqueous slurry according to claim 5, characterized in that, The modification process includes: adding 0.6-1.2 parts of silane-coupled acetylene black to 40-50 parts of N,N-dimethylformamide and ultrasonically dispersing for 10-20 min; adding 0.6-1.2 parts of 2-acrylamido-2-methylpropanesulfonic acid and 0.02-0.04 parts of 2,2'-azobisisobutyronitrile under a nitrogen atmosphere; heating to 80-90℃ and stirring for 6-8 h; washing with water; centrifuging; and drying to obtain modified acetylene black.

9. The graphene aqueous slurry according to claim 1, characterized in that, The dispersant is selected from polyethylene glycol or polyvinylpyrrolidone.

10. A method for preparing an aqueous graphene slurry, characterized in that, Includes the following steps: Disperse 4-6 parts of graphene composite material, 0.6-1.2 parts of acetylene black and 0.2-0.4 parts of dispersant in 90-100 parts of deionized water, and then grind for 4-6 hours to obtain graphene aqueous slurry.