Low-defect few-layer graphene aqueous conductive slurry, preparation method and application thereof

Abstract

The application discloses a kind of low-defect few-layer graphene water-based conductive paste and its preparation method and application, belong to conductive paste technical field;Low-defect few-layer graphene water-based conductive paste of the application, by weight fraction, including 1~3 mass fraction low-defect few-layer graphene, 100 mass fraction ultrapure water, 0.8~1.2 mass fraction conductive additive;The low-defect few-layer graphene is first to graphite powder at room temperature intercalation, then chemical expansion is carried out, and then water phase stripping is obtained using 5 '-adenine nucleotide salt aqueous solution;The conductive additive is amphiphilic polythiophene;The amphiphilic polythiophene is treated to obtain using hydrogen bromide and anhydrous acetic anhydride after polymerization with 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene, 3-[10-(4-methylphenyl ether) decyl)] thiophene as monomer;The low-defect few-layer graphene water-based conductive paste prepared by the application has less graphene defects, good dispersibility and good conductivity.

Description

TECHNICAL FIELD

[0001] The present application relates to a low-defect few-layer graphene aqueous conductive slurry, a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of new energy industry, the demand for high-performance conductive materials is increasing. Graphene, as a two-dimensional material with excellent electrical conductivity, high specific surface area and good mechanical properties, has shown broad application prospects in the fields of batteries, supercapacitors and conductive coatings. Among them, few-layer graphene (≤5 layers) is considered as an ideal conductive agent carrier due to its low electron transmission resistance and high structural integrity.

[0003] However, traditional graphene preparation methods have many problems that limit their performance. For example, the widely used Hummers method to prepare graphene oxide (GO) and then reduce graphene at high temperature can easily cause stacking between layers and produce a large number of structural defects in the reduction process, which significantly affects the electrical conductivity of the final material. In addition, the incomplete reduction of oxygen-containing functional groups also reduces the electrical conductivity of graphene.

[0004] In aqueous systems, graphene is prone to aggregation due to its strong van der Waals forces and π-π interactions, so it is usually necessary to add a dispersant to improve its dispersion stability. However, the use of dispersants also brings a series of problems, such as excessive dispersants adsorbed on the surface of graphene, occupying active sites, hindering direct contact between graphene and electrode materials, and weakening the construction of the conductive network; the residue of some dispersants in the battery system may cause the internal resistance to rise, affecting the high-current charge and discharge performance, and limiting its application in high-power devices, etc.

[0005] In addition, the current mainstream graphene preparation process has a difficult balance between controlling the number of layers and maintaining the integrity of the crystal lattice. Mechanical exfoliation methods (such as ultrasonic exfoliation or sanding) can reduce the number of graphene layers to a certain extent, but further reducing to few-layer (≤5 layers) requires a very long process time and low efficiency. Chemical reduction method, on the other hand, has certain advantages in layer number control, but the damage to sp² hybridization structure during graphene oxide reduction is still difficult to avoid. For example, although high-temperature thermal reduction (>800℃) helps to remove oxygen-containing groups and restore sp² structure, the process is often accompanied by problems such as layer curling and pore formation.

[0006] In summary, the development of a few-layer graphene aqueous conductive slurry that can balance low defect density, good dispersibility and excellent electrical conductivity is the key to promoting its wide application in high-performance electrochemical energy storage and other conductive materials fields. SUMMARY

[0007] The present application aims to provide a low-defect few-layer graphene aqueous conductive paste, a preparation method and application thereof, so as to solve the technical problems mentioned in the background.

[0008] The technical solution for achieving the object of the present application is as follows:

[0009] In the first aspect, the present application provides a low-defect few-layer graphene aqueous conductive paste, wherein the raw material components include 1-3 parts by mass of low-defect few-layer graphene, 100 parts by mass of ultrapure water, and 0.8-1.2 parts by mass of conductive additive.

[0010] Further, the low-defect few-layer graphene is obtained by first intercalating graphite powder at room temperature, then performing chemical expansion, and then performing aqueous phase stripping using an aqueous solution of 2', 3'-dideoxyadenosine 5'-triphosphate.

[0011] Further, the conductive additive is an amphiphilic polythiophene.

[0012] Further, the amphiphilic polythiophene is obtained by polymerization using 2, 5-dibromo-3-triethylene glycol monomethyl ether thiophene, 3-[10-(4-methylphenyl ether) decyl] thiophene, and 2, 4, 6-tris (5-bromothiophene-2-yl)-1, 3, 5-triazine as polymerization monomers, and then treating with hydrogen bromide and anhydrous acetic anhydride.

[0013] In the second aspect, the present application provides a preparation method of the low-defect few-layer graphene aqueous conductive paste according to the first aspect, comprising the following preparation steps:

[0014] (1) Each raw material component is weighed according to its mass fraction for standby use;

[0015] (2) The low-defect few-layer graphene weighed in step (1) is dispersed in 4-6 times its mass of anhydrous dimethyl sulfoxide under argon protection and ultrasonically dispersed for 55-65 min, then the conductive additive is added and ultrasonically dispersed for 25-35 min, then it is heated to 58-62℃, cooled to room temperature, stirred at 600-800 rpm for 23-25 h, then sodium hydride is added in three portions with an interval of 15-25 min between each addition, and the amount of each addition is 0.32-0.48 parts by mass, then it is heated to 70-80℃, stirred and refluxed for 5.5-6.5 h, then 18-20 parts by mass of ethyl acetate is added to quench, then 27-30 parts by mass of ethyl acetate is further added, then it is filtered, washed with dichloromethane and diethyl ether for 2-4 times in sequence, then it is dried in a vacuum oven at 50℃ until the weight is constant, and a low-defect few-layer graphene composite conductive material is obtained.

[0016] (3) mixing the low-defect few-layer graphene composite conductive material obtained in step (2) with the ultrapure water weighed in step (1), and ultrasonically dispersing for 55-65 min to obtain a low-defect few-layer graphene aqueous conductive slurry.

[0017] Further, the preparation steps of the low-defect few-layer graphene are as follows:

[0018] A1. mixing graphite powder and chromium trioxide at a mass ratio of 1:8-9, then adding 6-8 parts by mass of 36-38% hydrochloric acid, stirring at 1000-1400 rpm under sealed conditions for 110-130 min, then repeatedly filtering and washing with deionized water and acetone until the filtrate is neutral, and vacuum drying at 60°C to constant weight to obtain room-temperature intercalated graphite powder;

[0019] A2. immersing 0.2 parts by mass of the room-temperature intercalated graphite powder in 38-42 parts by mass of a 30% hydrogen peroxide solution, filtering after reacting for 23-25 h, then repeatedly filtering and washing with deionized water and acetone until the filtrate is neutral, and vacuum drying at 60°C to constant weight to obtain a graphene precursor;

[0020] A3. mixing 0.015-0.025 parts by mass of 2’,3’-dideoxyadenosine 5’-triphosphate sodium salt with 20 parts by mass of deionized water, stirring to dissolve, then adding 0.02 parts by mass of the graphene precursor, ultrasonically exfoliating at 10-15°C and 100 W for 55-65 min, centrifuging the mixed solution after ultrasonic exfoliation at 5000 rpm for 25-35 min to collect the supernatant, filtering and drying to obtain low-defect few-layer graphene.

[0021] Further, 78% of the low-defect few-layer graphene has a thickness of less than 2 nm, and 74% of the low-defect few-layer graphene has a flake diameter of 1-6 μm.

[0022] Further, the low-defect few-layer graphene has a ratio of D peak to G peak of not higher than 0.2.

[0023] Further, the preparation method of the amphiphilic polythiophene is as follows:

[0024] Under the condition of nitrogen protection, 0.51-0.53 mass parts of 3-[10-(4-methylphenyl ether) decyl] thiophene, 0.23-0.24 mass parts of 2,4,6-tris(5-bromothiophene-2-yl)-1,3,5-triazine are mixed, 6.3-7 mass parts of dry tetrahydrofuran is added, stirred for 10-20 min, then 0.194-0.196 mass parts of isopropyl magnesium chloride is added dropwise under the condition of ice bath for 1-3 s / drop, and the reaction is carried out under the condition of avoiding light and room temperature for 25-35 min to obtain the formatted monomer A; under the condition of nitrogen protection and ice bath, 0.194-0.196 mass parts of isopropyl magnesium chloride is added dropwise to 0.776-0.778 mass parts of 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene for 1-3 s / drop, and the reaction is carried out under the condition of avoiding light and room temperature for 25-35 min to obtain the formatted monomer B; under the condition of nitrogen protection, 0.0097-0.0099 mass parts of 1,3-bis(diphenylphosphine propane) nickel dichloride is mixed with 2.25 mass parts of tetrahydrofuran and stirred for 25-35 min, then the formatted monomer A is added dropwise under the condition of ice bath for 1-3 s / drop, after the dropwise addition is completed, the ice bath is removed, and the reaction is carried out under the condition of stirring and room temperature for 2.5-3.5 h; the formatted monomer B is added, and the reaction is continuously carried out under the condition of stirring and room temperature for 2.5-3.5 h; after the reaction is completed, the quenching is carried out with 1M hydrochloric acid under the condition of ice bath, then deionized water is used to extract the product until the aqueous phase is nearly colorless, the organic phase is collected, dried with anhydrous magnesium sulfate, filtered, and the solvent is removed by rotary evaporation under reduced pressure, then 10 mass parts of chloroform is added to dissolve and is added to n-hexane in batches to precipitate, centrifuged by a centrifuge at 5800 rpm for 2-3 times, each time for 10 min, to remove the oligomer with a small molecular weight and the unreacted monomer, pour off the upper poor solvent, and dried in a vacuum oven at 45 DEG C under vacuum for 7.5-8.5 h, then mixed with 20.1-20.3 mass parts of 48% hydrobromic acid and 20.1-20.3 mass parts of acetic anhydride under the condition of nitrogen protection, then heated to 99-101 DEG C, and the reaction is carried out for 20-25 h, then extracted with deionized water and diethyl ether for 2-4 times to obtain the organic phase, washed with saturated sodium bicarbonate solution until the organic phase is neutral, collect the organic phase, dry with anhydrous magnesium sulfate, filter, remove the solvent by rotary evaporation under reduced pressure, and dried in a vacuum oven at 45 DEG C under vacuum for 7.5-8.5 h to obtain the amphiphilic polythiophene.

[0025] In a third aspect, the application provides a use of the low-defect few-layer graphene aqueous conductive slurry according to the first aspect, in the preparation of a battery, a conductive paint, a conductive ink, a flexible sensor, or an electrothermal film.

[0026] By adopting the technical scheme, the application has the following beneficial effects:

[0027] (1) The low-defect few-layer graphene aqueous conductive slurry of the application, the raw material components include low-defect few-layer graphene, ultrapure water and conductive additives; the low-defect few-layer graphene aqueous conductive slurry is improved in the conductive performance by using low-defect few-layer graphene and adding conductive additives.

[0028] (2) The low-defect few-layer graphene of the application is prepared by first intercalating graphite at room temperature by using chromium trioxide and concentrated hydrochloric acid, then immersing in hydrogen peroxide for chemical expansion, decomposing and releasing oxygen under the catalysis of chromium ions to make the graphite highly stretch along the axial direction to form a fluffy and porous worm-like structure, and then using an aqueous solution of 2',3'-dideoxyadenosine 5'-triphosphate to obtain graphene with a thickness of less than 2nm, a ratio of D peak to G peak not higher than 0.15, and a low defect and few layers, and the graphene obtained by the aqueous phase stripping has good dispersibility, and no obvious sedimentation and slow concentration decrease after standing for two months, and good dispersion stability.

[0029] (3) The conductive additive of the low-defect few-layer graphene aqueous conductive slurry of the application is a polymer of 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene and 3-[10-(4-methylphenyl ether) decyl] thiophene with 2,4,6-tris(5-bromothiophene-2-yl)-1,3,5-triazine as the branched center, which is a branched structure of amphiphilic polythiophene, and hydrophilic branched chain triethylene glycol and hydrophobic branched chain bromodecane are introduced into the branched structure of amphiphilic polythiophene to give the conductive additive amphiphilicity and improve the dispersibility of the conductive additive in ultrapure water.

[0030] The preparation mechanism of the amphiphilic polythiophene is as follows:

[0031] .

[0032] (4) The low-defect few-layer graphene aqueous conductive slurry is prepared by pre-mixing low-defect few-layer graphene and a conductive additive, and then dispersing them in ultrapure water. In the low-defect few-layer graphene, the amphiphilic polythiophene is dispersed in the cavity of the branched structure of the amphiphilic polythiophene, so that the amphiphilic polythiophene and the low-defect few-layer graphene are uniformly dispersed. The imidazole on the 2', 3'-dideoxyadenosine 5'-triphosphate on the surface layer of the low-defect few-layer graphene reacts with the bromo-decane branched chain on the conductive additive to form an imidazolium salt, which further enhances the dispersibility of the low-defect few-layer graphene and the conductive additive in the ultrapure water, and forms a continuous conductive network with the low-defect few-layer graphene, thereby enhancing the conductivity of the low-defect few-layer graphene aqueous conductive slurry. DETAILED DESCRIPTION

[0033] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with specific embodiments.

[0034] Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0035] The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0036] The raw materials in the examples and comparative examples are as follows:

[0037] The graphite used is 80-120 mesh graphite powder with a purity of 99.95% purchased from Shanghai Aldrin Biochemical Technology Co., Ltd.

[0038] 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene: 3 parts by mass of (2,5-dibromo thiophene-3-yl) methanol and 100 parts by mass of dry dichloromethane were mixed under nitrogen protection, and the reaction liquid was stirred for 20 min under ice water bath condition to maintain the temperature at about 0°C. 4.98 parts by mass of phosphorus tribromide was added dropwise at 2s / drop under the condition of stirring at 1200 rpm, and then stirred at room temperature for 5h. 20 parts by mass of 10% sodium bicarbonate solution was added dropwise at 2s / drop to quench the reaction, convert the reacted phosphorus tribromide into water-soluble salts, then pass through a diatomite column to remove bromine and other impurities, add 50mL of dichloromethane solvent to separate, wash the organic phase with distilled water twice, add anhydrous magnesium sulfate powder and continuously stir to remove water in the organic phase, then filter to remove solid substances, obtain dry organic phase, remove the solvent by rotary evaporation, and obtain 2,5-dibromo-3-methyl bromothiophene;

[0039] Under nitrogen protection, 3 parts of triethylene glycol monomethyl ether was dissolved in 72 parts of tetrahydrofuran solvent, 0.5 parts of sodium hydride powder was added while stirring, a large amount of bubbles was observed, after the addition was completed, the reaction bottle was capped with an oil seal, and reacted at room temperature for 1 h, when there were no more bubbles in the solution, the oil seal was removed in time, and the temperature was raised to 80°C, 3 parts of 2,5-dibromo-3-methyl bromothiophene dissolved in 22.5 parts of tetrahydrofuran was added dropwise, and it was added dropwise for about 10 min, after 5 h of reaction, the organic phase was repeatedly extracted with ether three times, and then washed with distilled water twice, then the organic phase was taken and anhydrous magnesium sulfate was added to remove water, the solid material was removed by suction filtration, then the solvent was removed by reduced pressure distillation, and then column chromatography was used for separation and purification, the single eluent was a mixture of n-hexane: ethyl acetate = 7:3 (volume ratio), and then the purified solution was rotary evaporated to remove the solvent, and 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene was obtained;

[0040] The detailed preparation mechanism is as follows:

[0041] .

[0042] 3-[10-(4-methylphenyl ether) decyl] thiophene preparation steps: 0.616 parts of potassium hydroxide (0.616 g, 11 mmol) and 1.25 parts of p-methoxyphenol were dissolved in 13.6 parts of methanol to obtain a mixed solution A; 7.5 parts of 1,10-dibromodecane was dissolved in 13.6 parts of acetone at 56°C, and then the mixed solution A was added dropwise into the flask, the dropwise time was 1 h, and after refluxing for 30 h, a reduced pressure device was used for separation, and the separated residue was washed with 330 parts of boiling hexane, the solid was filtered out and washed again with an equal amount of boiling hexane, and then the filtered solid was subjected to column chromatography (silica gel, hexane / dichloromethane = 1 / 1, volume ratio) to obtain an intermediate product 1;

[0043] 1.6 parts of the intermediate product 1 was dissolved in 28.56 parts of dry ether to obtain an ether solution of the intermediate product 1; under argon, 0.224 parts of magnesium powder and 11 parts of dry ether were refluxed, and then the ether solution of the intermediate product 1 was added dropwise, the addition time was 3 hours, to obtain a mixed solution B; 0.026 parts of 1,3-bis(diphenylphosphine propane) nickel dichloride and 0.84 parts of 3-bromothiophene were dissolved in 15 parts of dry ether, and were heated in a second three-necked flask under reflux and argon protection, and then the mixed solution B was added, and the heating and refluxing was continued for 19 h, then cold 0.2M hydrochloric acid was used for hydrolysis, dichloromethane was used for extraction, the organic phase was washed with water until the solution was neutral, dried with magnesium sulfate, the ether was removed by a reduced pressure device, and then purified by a silica gel chromatography column (silica gel, n-hexane / ether = 15 / 1, volume ratio) to obtain 3-[10-(4-methylphenyl ether) decyl] thiophene.

[0044] The detailed preparation mechanism is as follows:

[0045] .

[0046] (Example 1)

[0047] A preparation method of a low-defect few-layer graphene aqueous conductive slurry, comprising the following preparation steps:

[0048] (1) The raw material components are weighed according to the following mass fractions for standby: 1 mass part of low-defect few-layer graphene, 100 mass parts of ultrapure water, and 1.2 mass parts of conductive additive;

[0049] (2) Under argon protection, the low-defect few-layer graphene weighed in step (1) is dispersed in 4 times its mass of anhydrous dimethyl sulfoxide and ultrasonically dispersed for 55 min, then the conductive additive is added, and ultrasonic dispersion is continued for 25 min, then it is warmed to 58°C, cooled to room temperature, and stirred at 600 rpm for 23 h, then sodium hydride is added in three portions with an interval of 15 min between each addition, and the amount of each addition is 0.32 mass parts, then it is warmed to 70°C, stirred under reflux for 5.5 h, then 18 mass parts of ethyl acetate is added to quench, then 27 mass parts of ethyl acetate is further added, then it is suction filtered, washed with dichloromethane and diethyl ether for 2 times in turn, then dried in a vacuum oven at 50°C to constant weight to obtain a low-defect few-layer graphene composite conductive material;

[0050] (3) The low-defect few-layer graphene composite conductive material obtained in step (2) is mixed with the ultrapure water weighed in step (1), ultrasonically dispersed for 55 min to obtain a low-defect few-layer graphene aqueous conductive slurry.

[0051] The preparation steps of the low-defect few-layer graphene are as follows:

[0052] A1. The graphite powder and chromium trioxide are mixed in a mass ratio of 1:8, then 6 mass parts of 36% hydrochloric acid is added, and the sealed condition is stirred at 1000 rpm for 110 min, then it is repeatedly suction filtered and washed with deionized water and acetone until the filtrate is neutral, and dried to constant weight at 60°C under vacuum to obtain room temperature intercalated graphite powder;

[0053] A2. 0.2 mass parts of room temperature intercalated graphite powder is immersed in 38 mass parts of 30% hydrogen peroxide solution, and after reaction for 23 h, it is suction filtered, then repeatedly suction filtered and washed with deionized water and acetone until the filtrate is neutral, and dried to constant weight at 60°C under vacuum to obtain graphene precursor;

[0054] A3. 0.015 parts by mass of 2', 3'-dideoxyadenosine 5'-triphosphate sodium salt was mixed and dissolved with 20 parts by mass of deionized water, and then 0.02 parts by mass of a graphene precursor was added. The mixture was ultrasonically exfoliated at 10°C for 55 min at 100 W. The exfoliated mixture was centrifuged at 5000 rpm for 25 min, and the supernatant was collected. The supernatant was subjected to suction filtration and drying to obtain low-defect few-layer graphene.

[0055] The thickness of 78% of the low-defect few-layer graphene was 2.5 nm, and the flake diameter of 71% of the low-defect few-layer graphene was 1 to 6 μm.

[0056] The ratio of the D peak to the G peak of the low-defect few-layer graphene was 0.18.

[0057] The amphiphilic polythiophene was prepared by the following method:

[0058] Under nitrogen protection, 0.51 parts by mass of 3-[10-(4-methylphenyl ether)decyl]thiophene, 0.23 parts by mass of 2,4,6-tris(5-bromothiophene-2-yl)-1,3,5-triazine are mixed, 6.3 parts by mass of dry tetrahydrofuran is added, stirred for 10 min, then 0.194 parts by mass of isopropyl magnesium chloride is added dropwise at 1 s / drop under ice bath conditions, and the reaction is carried out at room temperature for 25 min in the dark to obtain a formatted monomer A; under nitrogen protection and ice bath conditions, 0.194 parts by mass of isopropyl magnesium chloride is added dropwise at 1 s / drop to 0.776 parts by mass of 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene, and the reaction is carried out at room temperature for 25 min in the dark to obtain a formatted monomer B; under nitrogen protection, 0.0097 parts by mass of 1,3-bis(diphenylphosphine propane) nickel dichloride is mixed with 2.25 parts by mass of tetrahydrofuran and stirred for 25 min, then the formatted monomer A is added dropwise at 1 s / drop under ice bath conditions, after the addition is completed, the ice bath is removed, and the reaction is carried out at room temperature for 2.5 h, the formatted monomer B is added, and the reaction is continued at room temperature for 2.5 h, after the reaction is completed, the quenching is carried out with 1M hydrochloric acid under ice bath conditions, then the product is extracted with deionized water until the aqueous phase is nearly colorless, the organic phase is collected, dried with anhydrous magnesium sulfate, filtered, and the solvent is removed by rotary evaporation under reduced pressure, then 10 parts by mass of chloroform is dissolved and added to n-hexane in batches to precipitate, centrifuged twice by a centrifuge at 5800 rpm for 10 min each time to remove small molecular weight oligomers and unreacted monomers, the upper poor solvent is discarded, and vacuum drying is carried out in a vacuum oven at 45°C for 7.5 h, then 20.1 parts by mass of 48% hydrobromic acid and 20.1 parts by mass of acetic anhydride are mixed under nitrogen protection, then the temperature is raised to 99°C, and the reaction is carried out for 20 h, then the organic phase is extracted with deionized water and diethyl ether twice, washed with saturated sodium bicarbonate solution until the organic phase is neutral, the organic phase is collected, dried with anhydrous magnesium sulfate, filtered, and the solvent is removed by rotary evaporation under reduced pressure, and vacuum drying is carried out in a vacuum oven at 45°C for 7.5 h to obtain an amphiphilic polythiophene.

[0059] (Example 2)

[0060] A preparation method of a low-defect few-layer graphene aqueous conductive slurry, comprising the following preparation steps:

[0061] (1) The raw material components are weighed according to the following mass parts for standby use: 3 parts by mass of low-defect few-layer graphene, 100 parts by mass of ultrapure water, and 1 part by mass of conductive additive;

[0062] (2) under argon protection, the low-defect few-layer graphene weighed in step (1) is dispersed in 5 times of the mass of anhydrous dimethyl sulfoxide and ultrasonically dispersed for 60 min, then conductive additives are added and ultrasonic dispersion is continued for 30 min, then it is warmed to 60°C, cooled to room temperature, stirred at 700 rpm for 24 h, then sodium hydride is added in three portions, with an interval of 20 min between each addition, and the amount of each addition is 0.4 parts by mass, then it is warmed to 75°C, stirred and refluxed for 6 h, then 19 parts by mass of ethyl acetate is added to quench, then 28.5 parts by mass of ethyl acetate is added, then it is filtered, washed with dichloromethane and diethyl ether three times in turn, then it is dried in a vacuum oven at 50°C to constant weight, to obtain a low-defect few-layer graphene composite conductive material;

[0063] (3) the low-defect few-layer graphene composite conductive material obtained in step (2) is mixed with the ultrapure water weighed in step (1) and ultrasonically dispersed for 60 min, to obtain a low-defect few-layer graphene aqueous conductive slurry.

[0064] The preparation steps of the low-defect few-layer graphene are as follows:

[0065] A1. The graphite powder and chromium trioxide are mixed in a mass ratio of 1:8.5, then 7 parts by mass of 36% hydrochloric acid is added, and the mixture is stirred at 1200 rpm under sealed conditions for 120 min, then it is repeatedly filtered and washed with deionized water and acetone until the pH of the filtrate is neutral, and it is dried to constant weight at 60°C under vacuum, to obtain room-temperature intercalated graphite powder;

[0066] A2. The 0.2 parts by mass of room-temperature intercalated graphite powder is immersed in 40 parts by mass of 30% hydrogen peroxide solution, and after reaction for 24 h, it is filtered, then it is repeatedly filtered and washed with deionized water and acetone until the pH of the filtrate is neutral, and it is dried to constant weight at 60°C under vacuum, to obtain graphene precursor;

[0067] A3. 0.020 parts by mass of 2',3'-dideoxyadenosine 5'-triphosphate sodium salt is mixed with 20 parts by mass of deionized water and stirred to dissolve, then 0.02 parts by mass of graphene precursor is added, and the mixture is ultrasonically exfoliated at 13°C and 100 W for 60 min, then the mixture after ultrasonic exfoliation is centrifuged at 5000 rpm for 30 min to collect the supernatant, which is filtered and dried, to obtain low-defect few-layer graphene.

[0068] 78% of the low-defect few-layer graphene has a thickness of less than 1 nm, and 74% of the low-defect few-layer graphene has a flake diameter of 1-6 μm.

[0069] The ratio of the D peak to the G peak of the low-defect few-layer graphene is 0.16.

[0070] The preparation method of the amphiphilic polythiophene is as follows:

[0071] Under nitrogen protection, 0.52 parts by mass of 3-[10-(4-methylphenyl ether) decyl] thiophene, 0.235 parts by mass of 2,4,6-tris(5-bromothiophene-2-yl)-1,3,5-triazine were mixed, 6.7 parts by mass of dry tetrahydrofuran was added, stirred for 15 min, then 0.195 parts by mass of isopropyl magnesium chloride was added dropwise under ice bath condition at 2s / drop, and reacted for 30 min under light-proof room temperature condition to obtain the formatted monomer A; under nitrogen protection and ice bath condition, 0.195 parts by mass of isopropyl magnesium chloride was added dropwise at 2s / drop to 0.777 parts by mass of 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene, and reacted for 30 min under light-proof room temperature condition to obtain the formatted monomer B; under nitrogen protection, 0.0098 parts by mass of 1,3-bis(diphenylphosphine propane) nickel dichloride was mixed with 2.25 parts by mass of tetrahydrofuran and stirred for 30 min, then the formatted monomer A was added dropwise under ice bath condition at 2s / drop, after the addition was completed, the ice bath was removed, and the reaction was stirred for 3 h under room temperature; the formatted monomer B was added, and the reaction was continuously stirred for 3 h under room temperature; after the reaction was completed, the quenching was performed with 1M hydrochloric acid under ice bath condition, then deionized water was used to extract the product until the aqueous phase was nearly colorless; the organic phase was collected, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation under reduced pressure; then 10 parts by mass of chloroform was dissolved in n-hexane in batches to precipitate, and the centrifuge was used to centrifuge 3 times at 5800 rpm for 10 min each time to remove small molecular weight oligomers and unreacted monomers; the upper poor solvent was discarded, and vacuum drying was performed in a vacuum oven at 45℃ for 8 h; then 20.2 parts by mass of 48% hydrobromic acid and 20.2 parts by mass of acetic anhydride were mixed under nitrogen protection, and then the temperature was increased to 100℃; after the reaction was performed for 23 h, deionized water and diethyl ether were used to extract 3 times to obtain the organic phase; the saturated sodium bicarbonate solution was used to wash the organic phase until the organic phase was neutral; the organic phase was collected, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation under reduced pressure; vacuum drying was performed in a vacuum oven at 45℃ for 8 h to obtain the amphiphilic polythiophene.

[0072] (Example 3)

[0073] A preparation method of a low-defect few-layer graphene aqueous conductive slurry, comprising the following preparation steps:

[0074] (1) The raw material components are weighed according to the following mass parts for standby use: 3 parts by mass of low-defect few-layer graphene, 100 parts by mass of ultrapure water, and 0.8 parts by mass of conductive additive;

[0075] (2) under argon protection, the low-defect few-layer graphene weighed in step (1) is dispersed in 6 times its mass of anhydrous dimethyl sulfoxide and ultrasonically dispersed for 65 min, then conductive additives are added and ultrasonic dispersion is continued for 35 min, then it is warmed to 62°C, cooled to room temperature, stirred at 800 rpm for 25 h, then sodium hydride is added in three portions with an interval of 25 min between each addition, and the amount of each addition is 0.48 parts by mass, then it is warmed to 80°C, stirred under reflux for 6.5 h, then 20 parts by mass of ethyl acetate is added to quench, then 30 parts by mass of ethyl acetate is added, then it is filtered, washed with dichloromethane and diethyl ether 4 times in turn, then it is dried in a vacuum oven at 50°C to constant weight, to obtain a low-defect few-layer graphene composite conductive material;

[0076] (3) the low-defect few-layer graphene composite conductive material obtained in step (2) is mixed with the ultrapure water weighed in step (1), and ultrasonic dispersion is carried out for 65 min, to obtain a low-defect few-layer graphene aqueous conductive slurry.

[0077] The preparation steps of the low-defect few-layer graphene are as follows:

[0078] A1. graphite powder and chromium trioxide are mixed in a mass ratio of 1:9, then 8 parts by mass of 38% hydrochloric acid is added, and stirring is carried out at 1400 rpm under sealed conditions for 130 min, then it is repeatedly filtered and washed with deionized water and acetone until the pH of the filtrate is neutral, and it is dried to constant weight at 60°C under vacuum, to obtain room-temperature intercalated graphite powder;

[0079] A2. 0.2 parts by mass of room-temperature intercalated graphite powder is immersed in 42 parts by mass of 30% hydrogen peroxide solution, and after reaction for 25 h, it is filtered, then it is repeatedly filtered and washed with deionized water and acetone until the pH of the filtrate is neutral, and it is dried to constant weight at 60°C under vacuum, to obtain graphene precursor;

[0080] A3. 0.025 parts by mass of 2',3'-dideoxyadenosine 5'-triphosphate sodium salt is mixed with 20 parts by mass of deionized water and stirred to dissolve, then 0.02 parts by mass of graphene precursor is added, and ultrasonic exfoliation is carried out at 15°C and 100 W for 65 min, then the mixture after ultrasonic exfoliation is centrifuged at 5000 rpm for 35 min to collect the supernatant, and it is filtered and dried, to obtain low-defect few-layer graphene.

[0081] 78% of the low-defect few-layer graphene has a thickness of less than 1.5 nm, and 72% of the low-defect few-layer graphene has a flake diameter of 1-6 μm.

[0082] The ratio of the D peak to the G peak of the low-defect few-layer graphene is 0.16.

[0083] The preparation method of the amphiphilic polythiophene is as follows:

[0084] Under nitrogen protection, 0.53 parts by mass of 3-[10-(4-methylphenyl ether) decyl] thiophene, 0.24 parts by mass of 2,4,6-tris(5-bromothiophene-2-yl)-1,3,5-triazine were mixed, 7 parts by mass of dry tetrahydrofuran was added, stirred for 20 min, then 0.196 parts by mass of isopropyl magnesium chloride was added dropwise under ice bath condition at 3s / drop, and reacted for 35 min under light-proof room temperature condition to obtain the formatted monomer A; under nitrogen protection and ice bath condition, 0.778 parts by mass of 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene was added, 0.196 parts by mass of isopropyl magnesium chloride was added dropwise at 3s / drop, and reacted for 35 min under light-proof room temperature condition to obtain the formatted monomer B; under nitrogen protection, 0.0099 parts by mass of 1,3-bis(diphenylphosphine propane) nickel dichloride was mixed with 2.25 parts by mass of tetrahydrofuran and stirred for 35 min, then the formatted monomer A was added dropwise under ice bath condition at 3s / drop, after the addition was completed, the ice bath was removed, and the reaction was stirred for 3.5 h under room temperature; the formatted monomer B was added, and the reaction was continuously stirred for 3.5 h under room temperature; after the reaction was completed, the quenching was performed with 1M hydrochloric acid under ice bath condition, then deionized water was used to extract the product until the aqueous phase was nearly colorless, the organic phase was collected, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporator under reduced pressure; then 10 parts by mass of chloroform was added to n-hexane to precipitate, and the centrifuge was used to centrifuge 3 times at 5800 rpm for 10 min each time to remove the oligomer with small molecular weight and the unreacted monomer; the upper poor solvent was poured off, and vacuum drying was performed in a vacuum oven at 45℃ for 8.5 h; then 20.3 parts by mass of 48% hydrobromic acid and 20.3 parts by mass of acetic anhydride were mixed under nitrogen protection, and then the temperature was increased to 101℃; after the reaction was performed for 25 h, the organic phase was obtained by extracting with deionized water and diethyl ether for 4 times, and the aqueous phase was washed with saturated sodium bicarbonate solution until the organic phase was neutral; the organic phase was collected, dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporator under reduced pressure; vacuum drying was performed in a vacuum oven at 45℃ for 8.5 h to obtain the amphiphilic polythiophene.

[0085] (Comparative Example 1)

[0086] The difference between Comparative Example 1 and Example 2 is that the water phase stripping solution of Comparative Example 1 is a water solution of 0.020 parts by mass of sodium deoxycholate and 20 parts by mass of ultrapure water, and the other steps and components are the same as those of Example 2; 78% of the low-defect few-layer graphene has a thickness of less than 2 nm, and 70% of the low-defect few-layer graphene has a size of 1-6 μm; the ratio of D peak to G peak of the low-defect few-layer graphene is 0.21.

[0087] (Comparative Example 2)

[0088] The difference between Comparative Example 2 and Example 2 is that the conductive additive of Comparative Example 2 is 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene, 3-[10-(4-methylphenyl ether) decyl] thiophene, 2,4,6-tris(5-bromothiophene-2-yl)-1,3,5-triazine, which is polymerized and then treated with hydrogen bromide and anhydrous acetic anhydride. The remaining steps and components are the same as those of Example 2. 78% of the low-defect few-layer graphene has a thickness of less than 1.3 nm, and 75% of the low-defect few-layer graphene has a flake size of 1-6 μm. The ratio of the D peak to the G peak of the low-defect few-layer graphene is 0.16.

[0089] (Comparative Example 3)

[0090] The difference between Comparative Example 3 and Example 2 is that the conductive additive of Comparative Example 3 is 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene, 2,4,6-tris(5-bromothiophene-2-yl)-1,3,5-triazine, which is polymerized and then treated with hydrogen bromide and anhydrous acetic anhydride. The remaining steps and components are the same as those of Example 2. 78% of the low-defect few-layer graphene has a thickness of less than 1.4 nm, and 73% of the low-defect few-layer graphene has a flake size of 1-6 μm. The ratio of the D peak to the G peak of the low-defect few-layer graphene is 0.17.

[0091] (Comparative Example 4)

[0092] The difference between Comparative Example 4 and Example 2 is that the conductive additive of Comparative Example 4 is 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene, 3-[10-(4-methylphenyl ether) decyl] thiophene, 2,4,6-tris(5-bromothiophene-2-yl)-1,3,5-triazine, which is polymerized. The remaining steps and components are the same as those of Example 2. 78% of the low-defect few-layer graphene has a thickness of less than 1.1 nm, and 75% of the low-defect few-layer graphene has a flake size of 1-6 μm. The ratio of the D peak to the G peak of the low-defect few-layer graphene is 0.16.

[0093] (Comparative Example 5)

[0094] The difference between Comparative Example 5 and Example 2 is that the low-defect few-layer graphene aqueous conductive slurry of Comparative Example 5 directly mixes and disperses the low-defect few-layer graphene, the conductive additive, and ultrapure water weighed in step (1). The remaining steps and components are the same as those of Example 2. 78% of the low-defect few-layer graphene has a thickness of less than 1.2 nm, and 74% of the low-defect few-layer graphene has a flake size of 1-6 μm. The ratio of the D peak to the G peak of the low-defect few-layer graphene is 0.16.

[0095] (Effect Example)

[0096] Viscosity: The rotating viscometer method described in DB13 / T 5026.1-2019 was used for detection.

[0097] Measurement of slurry pole piece resistivity: The four-probe method described in DB13 / T 5026.3-2019 was used for detection.

[0098] Table 1 below is the performance test results of the low-defect few-layer graphene aqueous conductive slurry prepared in Examples 1-3 and Comparative Examples 1-5:

[0099] Table 1

[0100] Tab sheet resistivity (Ω*cm) Viscosity (mPa*s) Viscosity after 2 months standing (mPa*s) Example 1 21.8 1134 1270 Example 2 20.6 1109 1208 Example 3 21.2 1125 1237 Comparative Example 1 24.7 1142 1324 Comparative Example 2 21.6 1132 1290 Comparative Example 3 24.1 1128 1274 Comparative Example 4 23.7 1126 1272 Comparative Example 5 28.3 1619 3076

[0101] As can be seen from Table 1 and the graphene test data of the examples and comparative examples, the low-defect few-layer graphene prepared in Examples 1-3 has fewer defects, better dispersibility in the prepared low-defect few-layer graphene aqueous conductive slurry, and still maintains good dispersibility after two months of standing; and the low-defect few-layer graphene aqueous conductive slurry prepared has higher conductivity.

[0102] The difference between Comparative Example 1 and Example 2 is that the water phase exfoliation solution of Comparative Example 1 is a water solution of 0.020 parts by mass of sodium deoxycholate mixed with 20 parts by mass of ultrapure water, instead of the aqueous solution of 5'-adenine nucleotide salt of Example 2. The low-defect few-layer graphene aqueous conductive slurry prepared in Example 2 has higher conductivity, better dispersibility, and still maintains a high level of dispersibility after two months of standing, and has good dispersion stability, compared with Comparative Example 1.

[0103] The difference between Comparative Example 2 and Example 2 is that the conductive additive of Comparative Example 2 is prepared by treating 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene and 3-[10-(4-methylphenyl ether) decyl] thiophene after polymerization with hydrogen bromide and anhydrous acetic anhydride, and Example 2 further adds 2,4,6-tris(5-bromothiophene-2-yl)-1,3,5-triazine. The low-defect few-layer graphene aqueous conductive slurry prepared has good dispersibility, and still maintains a high level of dispersibility after two months of standing, and has good dispersion stability.

[0104] The difference between Comparative Example 3 and Example 2 is that the conductive additive of Comparative Example 3 is prepared by treating 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene and 2,4,6-tris(5-bromothiophene-2-yl)-1,3,5-triazine after polymerization with hydrogen bromide and anhydrous acetic anhydride, and Example 2 further adds 3-[10-(4-methylphenyl ether) decyl] thiophene. The low-defect few-layer graphene aqueous conductive slurry prepared has good dispersibility, and still maintains a high level of dispersibility after two months of standing, and has good dispersion stability, and the low-defect few-layer graphene aqueous conductive slurry prepared has higher conductivity.

[0105] The difference between Comparative Example 4 and Example 2 is that the conductive additive of Comparative Example 4 is prepared by polymerization of 2,5-dibromo-3-triethylene glycol monomethyl ether thiophene, 3-[10-(4-methylphenyl ether) decyl] thiophene, 2,4,6-tris(5-bromothiophene-2-yl)-1,3,5-triazine. The low-defect few-layer graphene aqueous conductive slurry prepared in Example 2 has good dispersibility, and the dispersibility can still maintain a high level after standing for 2 months, and has good dispersion stability. The low-defect few-layer graphene aqueous conductive slurry prepared has high conductivity.

[0106] The difference between Comparative Example 5 and Example 2 is that the low-defect few-layer graphene aqueous conductive slurry of Comparative Example 5 is directly mixed and dispersed by the low-defect few-layer graphene, the conductive additive and ultrapure water weighed in step (1), instead of pre-mixing the low-defect few-layer graphene and the conductive additive as in Example 2. The low-defect few-layer graphene aqueous conductive slurry prepared in Example 2 has good dispersibility, and the dispersibility can still maintain a high level after standing for 2 months. The low-defect few-layer graphene aqueous conductive slurry prepared has high conductivity

[0107] The above specific examples further illustrate the purpose, technical solutions and advantages of the present application. It should be understood that the above description is only for specific embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A low-defect few-layer graphene aqueous conductive paste, characterized by, The raw material components include 1-3 parts by mass of low-defect few-layer graphene, 100 parts by mass of ultrapure water, and 0.8-1.2 parts by mass of a conductive additive; The low-defect few-layer graphene is obtained by intercalating graphite powder at room temperature, then performing chemical expansion, and then performing aqueous phase exfoliation using an aqueous solution of 2', 3'-dideoxyadenosine 5'-triphosphate; the conductive additive is an amphiphilic polythiophene; the amphiphilic polythiophene is obtained by polymerization using 2, 5-dibromo-3-triethylene glycol monomethyl ether thiophene, 3-[10-(4-methylphenyl ether) decyl] thiophene, and 2, 4, 6-tris (5-bromothiophene-2-yl)-1, 3, 5-triazine as polymerization monomers, and then treating with hydrogen bromide and anhydrous acetic anhydride; 78% of the low-defect few-layer graphene has a thickness of less than 2 nm, and 74% of the low-defect few-layer graphene has a flake diameter of 1-6 μm; the ratio of the D peak to the G peak of the low-defect few-layer graphene is not higher than 0.

2.

2. A method for preparing a low-defect oligolayer graphene aqueous conductive paste as described in claim 1, characterized in that, The preparation steps include: (1) Each raw material component is weighed according to the respective mass fraction for standby use; (2) The low-defect few-layer graphene weighed in step (1) is dispersed in 4-6 times its mass of anhydrous dimethyl sulfoxide under argon protection and ultrasonic dispersion for 55-65 min, then the conductive additive is added, and ultrasonic dispersion is continued for 25-35 min, then it is warmed to 58-62°C, cooled to room temperature, and stirred at 600-800 rpm for 23-25 h, then sodium hydride is added in three portions, with an interval of 15-25 min between each addition, and the amount of each addition is 0.32-0.48 parts by mass, then it is warmed to 70-80°C, stirred under reflux for 5.5-6.5 h, then 18-20 parts by mass of ethyl acetate is added to quench, then 27-30 parts by mass of ethyl acetate is added, then it is filtered, washed with dichloromethane and diethyl ether for 2-4 times in sequence, then it is dried in a vacuum oven at 50°C until the weight is constant, to obtain a low-defect few-layer graphene composite conductive material; (3) The low-defect few-layer graphene composite conductive material obtained in step (2) is mixed with the ultrapure water weighed in step (1), and ultrasonic dispersion is performed for 55-65 min, to obtain a low-defect few-layer graphene aqueous conductive slurry.

3. The method for preparing low-defect oligolayer graphene aqueous conductive paste according to claim 2, characterized in that, The preparation steps of the low-defect few-layer graphene are as follows: A1. Graphite powder and chromium trioxide are mixed in a mass ratio of 1:8-9, then 6-8 parts by mass of 36-38% hydrochloric acid is added, and stirring is performed at 1000-1400 rpm under sealed conditions for 110-130 min, then it is repeatedly filtered and washed with deionized water and acetone until the pH of the filtrate is neutral, and it is dried in a vacuum oven at 60°C until the weight is constant, to obtain room-temperature intercalated graphite powder; A2. 0.2 parts by mass of the room-temperature intercalated graphite powder is immersed in 38-42 parts by mass of a 30% hydrogen peroxide solution, and after reaction for 23-25 h, it is filtered, then it is repeatedly filtered and washed with deionized water and acetone until the pH of the filtrate is neutral, and it is dried in a vacuum oven at 60°C until the weight is constant, to obtain a graphene precursor; A3. 0.015-0.025 parts by mass of 2', 3'-dideoxyadenosine 5'-triphosphate sodium salt is mixed with 20 parts by mass of deionized water and stirred to dissolve, then 0.02 parts by mass of graphene precursor is added, and 100 W ultrasonic peeling is performed at 10-15℃ for 55-65 min. The mixed solution after ultrasonic peeling is centrifuged at 5000 rpm for 25-35 min to collect the supernatant, and then subjected to suction filtration and drying to obtain low-defect few-layer graphene.

4. The method of claim 2, wherein the low-defect few-layer graphene aqueous conductive ink is prepared by the steps of: The preparation method of the amphiphilic polythiophene is as follows: Under nitrogen protection, 0.51-0.53 parts by mass of 3-[10-(4-methylphenyl ether) decyl] thiophene, 0.23-0.24 parts by mass of 2, 4, 6-tris (5-bromothiophene-2-yl) -1, 3, 5-triazine are mixed, 6.3-7 parts by mass of dry tetrahydrofuran is added, stirred for 10-20 min, then 0.194-0.196 parts by mass of isopropyl magnesium chloride is added dropwise at 1-3 s / drop under ice bath condition, and the reaction is carried out at room temperature for 25-35 min to obtain the formatted monomer A; under nitrogen protection and ice bath condition, 0.194-0.196 parts by mass of isopropyl magnesium chloride is added dropwise at 1-3 s / drop to 0.776-0.778 parts by mass of 2, 5-dibromo-3-triethylene glycol monomethyl ether thiophene, and the reaction is carried out at room temperature for 25-35 min to obtain the formatted monomer B; under nitrogen protection, 0.0097-0.0099 parts by mass of 1, 3-bis (diphenylphosphine propane) nickel dichloride is mixed with 2.25 parts by mass of tetrahydrofuran and stirred for 25-35 min, then the formatted monomer A is added dropwise at 1-3 s / drop under ice bath condition, after the addition is completed, the ice bath is removed, and the reaction is carried out at room temperature for 2.5-3.5 h, the formatted monomer B is added, and the reaction is continued at room temperature for 2.5-3.5 h, after the reaction is completed, the reaction is quenched with 1M hydrochloric acid under ice bath condition, then the product is extracted with deionized water until the aqueous phase is nearly colorless, the organic phase is collected, dried with anhydrous magnesium sulfate, filtered, and the solvent is removed by rotary evaporator under reduced pressure, then 10 parts by mass of chloroform is added to n-hexane in batches to precipitate, the mixture is centrifuged by centrifuge at 5800 rpm for 2-3 times, each time for 10 min, the oligomers with small molecular weight and unreacted monomers are removed, the supernatant is discarded, and vacuum drying is carried out at 45℃ in a vacuum oven for 7.5-8.5 h, then 20.1-20.3 parts by mass of 48% hydrobromic acid, 20.1-20.3 parts by mass of acetic anhydride are mixed under nitrogen protection, then the temperature is raised to 99-101℃, the reaction is carried out for 20-25 h, then the organic phase is obtained by extracting with deionized water and diethyl ether for 2-4 times, the organic phase is washed with saturated sodium bicarbonate solution until the organic phase is neutral, the organic phase is collected, dried with anhydrous magnesium sulfate, filtered, and the solvent is removed by rotary evaporator under reduced pressure, and vacuum drying is carried out at 45℃ in a vacuum oven for 7.5-8.5 h to obtain the amphiphilic polythiophene.

5. Use of the low-defect few-layer graphene aqueous conductive paste according to claim 1, characterized in that, The low-defect few-layer graphene aqueous conductive slurry is applied in the preparation of batteries, conductive coatings, conductive inks, flexible sensors, and electrothermal films.