CN110606481A - A kind of thin layer graphene oxide dispersion liquid and preparation method thereof - Google Patents

Abstract

The invention discloses a few-layer graphene oxide dispersion liquid and a preparation method thereof. Mix strong acid, graphite powder and permanganate evenly at 10-20°C and add them into the ball mill tank, mill at 100-150 rpm for 1-1.5 hours, 300-350 rpm for 1.5-2.0 hours, 500- Ball milling at 550 rpm for 2.0 to 2.5 hours, adding water and hydrogen peroxide to the ball milling product, and then centrifuging and washing the product to obtain a sheet with ≤3 layers, a thickness of 1 to 3 nm, and a specific surface area of 600 to 900 m ² /g, containing Graphene oxide with an oxygen content of 25% to 30%. The innovation of the invention lies in promoting the dispersion of graphite and the penetration and oxidation of oxidants through ball milling, which reduces the oxidant and water consumption by more than 50% compared with the traditional Hummers method, and reduces the operation and energy consumption of low temperature and high temperature control in the preparation process , to achieve efficient and rapid preparation of few-layer graphene oxide dispersion. Compared with the Hummers method, the preparation time is shortened by about 20 hours, and the amount of waste water is reduced by 80%. The prepared graphene oxide can be used for adsorption, strengthening and toughening of composite materials, and the like.

Description

A kind of thin layer graphene oxide dispersion liquid and preparation method thereof

technical field

The invention relates to a graphene oxide functional material and a preparation method thereof, in particular to a few-layer graphene oxide dispersion and a preparation method thereof.

Background technique

Graphene is a two-dimensional carbon nanomaterial composed of carbon atoms with sp ² hybrid orbitals in a hexagonal honeycomb lattice. Graphene oxide is a derivative of graphene, which has the same structure as graphene. With a six-membered ring structure and rich oxygen-containing functional groups on the surface, it is widely used in electronic devices, optics, biomedicine, adsorption, and composite materials because of its large specific surface area, good mechanical properties, and certain thermal and electrical conductivity. It has great development prospects in terms of strengthening and toughening.

Since the first successful preparation of graphene oxide in the 19th century, the current preparation methods of graphene oxide mainly include Brodie method, Staudenmaier method and Hummers method. The Brodie method was first discovered by Brodie in 1859. Concentrated nitric acid and potassium chlorate were sequentially added to graphite to react to prepare graphene oxide, and graphene oxide was prepared for the first time. 40 years later, Staudenmaier improved the acidity of the mixture by replacing 2/3 of the volume of concentrated nitric acid with concentrated sulfuric acid, which reduced the pollution and explosion hazard of concentrated nitric acid, and improved the degree of oxidation, but this method still has the risk of explosion. Releases toxic gas. Later, Hummers and Offeman developed another method for preparing graphene oxide called the Hummers method in 1958. This method dissolves sodium nitrate and potassium permanganate into concentrated sulfuric acid to prepare graphene oxide, which is comparable to other methods. Compared with Hummers method, which has the characteristics of high safety and high efficiency, it is currently the most widely used method for preparing graphene oxide.

In recent years, people have continuously improved the Hummers method to form the improved Hummers method, but the improved Hummers method has problems such as complex process operation, long reaction time, harmful gas and difficult-to-treat wastewater discharge. These problems cannot be ignored. It is beneficial to large-scale industrial application. Therefore, how to continue to improve the preparation method of graphene oxide, so that the improved preparation method no longer has the disadvantages of complicated process operation, long reaction time, harmful gas generation and refractory waste water, has become an urgent need in promoting the industrial application of graphene oxide. solved problem.

Contents of the invention

The object of the present invention is to provide a method for preparing a few-layer graphene oxide dispersion by a wet grinding oxidation method with simple operation, high preparation efficiency and less pollutant generation.

In order to achieve the above object, the technical scheme adopted in the present invention is:

Step 1: Add 10-20 parts of strong acid into the reactor according to parts by mass and control the temperature of the system at 10-20°C. While stirring, add the mixture of 1-2 parts of graphite powder and 3-5 parts of permanganate into the reaction In the container, keep the temperature of the system at 10-20°C during the feeding process, and maintain the temperature at 10-20°C after the feeding is completed and continue to stir to obtain the reaction mixture;

Step 2: transfer the reaction mixture obtained in step 1 to the ball mill tank of the ball mill, and start to carry out wet ball milling in three stages. The mass ratio of ball to material during ball milling is 300-400:1, and the ball milling speed in the first stage is 100-150 rpm; the second stage ball milling speed is 300-350 rpm; the third stage ball milling speed is 500-550 rpm, and the ball milling product is obtained after the ball milling is completed;

Step 3: Take out the ball milling product obtained in Step 2 and transfer it to the reactor, add 100-150 parts of water into the reactor while stirring, cool down the product in the reactor to 35-40°C, and then add hydrogen peroxide 5 into the reactor ~10 parts, and finally the product was subjected to repeated centrifugal precipitation and washing until no sulfate radical was detected in the washing liquid with a barium chloride solution, that is, a few-layer graphene oxide dispersion liquid was obtained.

The strong acid described in step 1 is formed by mixing concentrated sulfuric acid and concentrated phosphoric acid at a mass ratio of 10:2, wherein the mass fraction concentration of the concentrated sulfuric acid used is 98%, and the mass fraction concentration of the concentrated phosphoric acid used is 85%.

The particle size of the graphite powder in step one is 200-400 mesh, and the carbon content is 90%-99%.

The permanganate described in the step 1 is one of potassium permanganate, sodium permanganate and lithium permanganate, all of which have a particle size of 100 mesh and a purity greater than 99%.

In step 1, the mixture of 1-2 parts of graphite powder and 3-5 parts of permanganate is added into the reactor within 15-20 minutes, and the time for continuing stirring is 0.5-1 hour.

The ball mill described in step 2 is a planetary ball mill, and the grinding balls are 2mm, 4mm, 6mm, 8mm, 10mm, 12mm, 15mm in diameter, and the corresponding mass ratio is 10～15:15～20:20～25:25～30: 30～35:35～40:40～45 stainless steel balls, and the ball mill tank is made of nylon.

The ball milling time of the first stage in step 2 is 1-1.5 hours, the ball milling time of the second stage is 1.5-2 hours, and the ball milling time of the third stage is 2-2.5 hours.

In step 3, 100 to 150 parts of water are added to the reactor within 25 to 30 minutes while stirring, and the hydrogen peroxide is industrially pure with a mass fraction of 30%, and the hydrogen peroxide is added to the reactor within 20 to 25 minutes to chlorinate The mass fraction concentration of the barium solution is 25%, which is prepared by dissolving analytically pure barium chloride in deionized water.

The operation process of repeated centrifugal precipitation and washing described in step 3 is to use a high-speed centrifuge at 10,000 to 15,000 rpm for 3 to 5 minutes. The lower layer of the centrifuge tube is the graphene oxide precipitate, and the upper layer is the clear liquid, and then pour Remove the supernatant from the centrifuge tube, then add deionized water to the original supernatant in the centrifuge tube, stir evenly with a glass rod, and then repeat the operation process of centrifugal precipitation and washing.

The graphene oxide sheet in the few-layer graphene oxide dispersion prepared by the preparation method of the present invention has ≤3 layers, the thickness is 1-3 nm, the sheet size is 0.2-1.2 μm, and the specific surface area is 600-900 m ² /g , the oxygen content is 25% to 30%. High degree of oxidation, excellent performance.

Compared with prior art, the beneficial effect of the present invention is:

In the present invention, under the action of friction and shear force generated during ball milling, the graphite powder is modified, oxidized and dispersed, and the force and temperature required by the system can be maintained by regulating the ball milling speed in the three ball milling stages of step 2). In the preparation process of the present invention, only the rotational speed of the ball mill needs to be adjusted, and the operation is simple; the preparation of graphene oxide by the traditional Hummers method takes 23 to 30 hours, but this method only takes 5 to 7 hours, which greatly reduces the reaction time and has high preparation efficiency; The mechanical friction and frictional heat generated by the invention of the ball milling process can maintain a certain temperature and is conducive to the penetration and oxidation of permanganate between graphite sheets. The preparation of 1 to 2 parts of graphene only requires 10 to 100 grams of strong acid. 20 parts and 3 to 5 parts of permanganate, compared with the traditional Hummers method using 60 to 80 parts of strong acid and 6 to 10 parts of permanganate, it significantly reduces the amount of strong acid and permanganate, and There is no need to use sodium nitrate, so the present invention not only saves raw materials, but also reduces pollutants such as harmful gases and harmful liquids caused by the use of strong acids, permanganate, and nitric acid; the graphene oxide sheets in the obtained graphene oxide dispersion The layers have a smaller thickness and sheet planar size and a larger specific surface area than the Hummers method. At the same time, compared with the traditional Hummers method, the present invention increases the low-temperature reaction temperature from 0-5°C to 20-30°C, which facilitates operation and reduces costs; reduces the high-temperature reaction temperature from 80-95°C to 50-60°C, The operation is convenient, the cost is reduced, the safety of the reaction is improved, and it is suitable for popularization and use in a large area.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments.

Example 1:

Step 1: Mix concentrated sulfuric acid with a mass fraction of 98% and concentrated phosphoric acid with a mass fraction of 85% according to a mass ratio of 10:2 to obtain a strong acid solution, and then take 10 parts of the strong acid solution according to the number of parts by mass and add it to the reactor. The temperature of the control system is 20°C, and while stirring, 1 part of graphite powder with a particle size of 200-400 mesh and a carbon content of 90% to 99% and 3 parts of sodium permanganate with a particle size of 100 mesh and a purity greater than 99% The mixture was added into the reactor within 15 minutes, and the temperature of the system was kept at 20° C. during the addition. After the addition, the temperature was maintained at 20° C. and continued to stir for 0.5 hours to obtain a reaction mixture;

Step 2: Transfer the reaction mixture obtained in Step 1 to the nylon material ball milling tank of the planetary ball mill, and start to carry out wet ball milling in three stages. 4mm, 6mm, 8mm, 10mm, 12mm, 15mm, the corresponding mass ratio is 10:15:20:25:30:35:40 stainless steel balls, the ball milling speed in the first stage is 100 rpm ball milling for 1 hour, the ball milling process The heat generated will keep the temperature of the first stage system at 20°C; the second stage ball milling speed is 300 rpm ball milling for 1.5 hours, the heat generated during the ball milling process will keep the second stage system temperature at 40°C; the third stage ball milling The rotation speed is 500 rpm ball milling for 2 hours, the heat generated during the ball milling process will keep the temperature of the third-stage system at 50°C, and the ball milling product will be obtained after the ball milling is completed;

Step 3: Take out the ball milled product obtained in Step 2 and transfer it to the reactor, add 100 parts of water into the reactor within 25 minutes while stirring, cool down the product in the reactor to 40°C, and then pour it into the reactor within 20 minutes Add 5 parts of hydrogen peroxide with a mass fraction of 30%, and the color of the system will turn bright yellow. Use a 10,000-15,000 rpm high-speed centrifuge to centrifuge for 3-5 minutes. The lower layer of the centrifuge tube is graphene oxide precipitate, and the upper layer is Then pour off the supernatant of the centrifuge tube, then add deionized water to the position of the original supernatant in the centrifuge tube, stir evenly with a glass rod, and then repeat the centrifugal precipitation and washing until the washing liquid is filled with barium chloride solution The presence of sulfate radicals cannot be detected, and a few-layer graphene oxide dispersion is obtained.

The graphene oxide sheet prepared in this example has about 3 layers, a thickness of 2.98 nm, a specific surface area of 610 m ² /g, and an oxygen content of 25%.

Example 2:

Step 1: Mix concentrated sulfuric acid with a mass fraction of 98% and concentrated phosphoric acid with a mass fraction of 85% according to a mass ratio of 10:2 to obtain a strong acid solution, and then take 18 parts of the strong acid solution according to the mass fraction and add it to the reactor. The temperature of the control system is 15°C, and while stirring, 1 part of graphite powder with a particle size of 200-400 mesh and a carbon content of 90% to 99% and 3 parts of lithium permanganate with a particle size of 100 mesh and a purity greater than 99% Add the mixture into the reactor within 15 minutes, keep the temperature of the system at 15°C during the addition, maintain the temperature at 15°C after the addition, and continue stirring for 1 hour to obtain a reaction mixture;

Step 2: transfer the reaction mixture obtained in step 1 to the nylon material ball milling tank of the planetary ball mill, and start to carry out wet ball milling in three stages. 4mm, 6mm, 8mm, 10mm, 12mm, 15mm, the corresponding mass ratio is 12:16:21:26:31:36:42 stainless steel balls, the first stage ball milling speed is 150 rpm ball milling 1.5 hours, the ball milling process The heat generated will keep the temperature of the first stage system at 25°C; the second stage ball milling speed is 310 rpm ball milling for 1.5 hours, the heat generated during the ball milling process will keep the second stage system temperature at 45°C; the third stage ball milling The rotation speed is 500 rpm ball milling for 2 hours, the heat generated during the ball milling process will keep the temperature of the third stage system at 55°C, and the ball milling product will be obtained after the ball milling is completed;

Step 3: Take out the ball milling product obtained in Step 2 and transfer it to the reactor, add 150 parts of water into the reactor within 30 minutes while stirring, cool down the product in the reactor to 37°C, and then pour it into the reactor within 20 minutes Add 5 parts of hydrogen peroxide with a mass fraction of 30%, and the color of the system will turn bright yellow. Use a 10,000-15,000 rpm high-speed centrifuge to centrifuge for 3-5 minutes. The lower layer of the centrifuge tube is graphene oxide precipitate, and the upper layer is Then pour off the supernatant of the centrifuge tube, then add deionized water to the position of the original supernatant in the centrifuge tube, stir evenly with a glass rod, and then repeat the centrifugal precipitation and washing until the washing liquid is filled with barium chloride solution The presence of sulfate radicals cannot be detected, and a few-layer graphene oxide dispersion is obtained.

The graphene oxide sheet prepared in this example has about 2 layers, a thickness of 2.1 nm, a specific surface area of 714 m ² /g, and an oxygen content of 26%.

Example 3:

Step 1: Mix concentrated sulfuric acid with a mass fraction of 98% and concentrated phosphoric acid with a mass fraction of 85% according to a mass ratio of 10:2 to obtain a strong acid solution, and then take 20 parts of the strong acid solution in parts by mass and add it to the reactor and The temperature of the control system is 10°C, and 2 parts of graphite powder with a particle size of 200-400 mesh and a carbon content of 90% to 99% and 5 parts of potassium permanganate with a particle size of 100 mesh and a purity greater than 99% are mixed while stirring. Add the mixture into the reactor within 20 minutes, keep the temperature of the system at 10°C during the addition, maintain the temperature at 10°C after the addition, and continue stirring for 1 hour to obtain a reaction mixture;

Step 2: Transfer the reaction mixture obtained in Step 1 to the nylon material ball milling tank of the planetary ball mill, and start to carry out wet ball milling in three stages. During ball milling, the mass ratio of ball to material is 400: 1. 4mm, 6mm, 8mm, 10mm, 12mm, 15mm, the corresponding mass ratio is 13:18:23:28:33:38:43 stainless steel balls, the first stage ball milling speed is 150 rpm ball milling 1.5 hours, ball milling process The heat generated will keep the temperature of the first stage system at 30°C; the second stage ball milling speed is 320 rpm ball milling for 2 hours, the heat generated during the ball milling process will keep the second stage system temperature at 48°C; the third stage ball milling The rotation speed is 550 rpm ball milling for 2.5 hours, the heat generated during the ball milling process will keep the temperature of the third stage system at 60°C, and the ball milling product will be obtained after the ball milling is completed;

Step 3: Take out the ball milling product obtained in Step 2 and transfer it to the reactor, add 150 parts of water into the reactor within 30 minutes while stirring, cool down the product in the reactor to 35°C, and then pour it into the reactor within 25 minutes Add 10 parts of hydrogen peroxide with a mass fraction of 30%, and the color of the system will turn bright yellow. Use a high-speed centrifuge at 10,000 to 15,000 rpm for 3 to 5 minutes. The lower layer of the centrifuge tube is graphene oxide precipitate, and the upper layer is Then pour off the supernatant of the centrifuge tube, then add deionized water to the position of the original supernatant in the centrifuge tube, stir evenly with a glass rod, and then repeat the centrifugal precipitation and washing until the washing liquid is filled with barium chloride solution The presence of sulfate radicals cannot be detected, and a few-layer graphene oxide dispersion is obtained.

The graphene oxide sheet prepared in this example is about one layer, with a thickness of 1.03 nm, a specific surface area of 882 m ² /g, and an oxygen content of 30%.

Example 4:

Step 1: Mix concentrated sulfuric acid with a mass fraction of 98% and concentrated phosphoric acid with a mass fraction of 85% according to a mass ratio of 10:2 to obtain a strong acid solution, and then take 13 parts of the strong acid solution in parts by mass and add it to the reactor and The temperature of the control system is 14°C, and while stirring, 1 part of graphite powder with a particle size of 200-400 mesh and a carbon content of 90% to 99% and 5 parts of sodium permanganate with a particle size of 100 mesh and a purity greater than 99% The mixture was added into the reactor within 18 minutes, and the temperature of the system was kept at 14°C during the addition process. After the addition, the temperature was maintained at 14°C and continued to stir for 0.5 hours to obtain a reaction mixture;

Step 2: Transfer the reaction mixture obtained in Step 1 to the nylon ball milling tank of the planetary ball mill, and start to carry out wet ball milling in three stages. The mass ratio of ball to material during ball milling is 330:1. 4mm, 6mm, 8mm, 10mm, 12mm, 15mm, the corresponding mass ratio is 14:19:24:29:34:39:44 stainless steel balls, the ball milling speed in the first stage is 100 rpm ball milling for 1 hour, the ball milling process The heat generated will keep the temperature of the first stage system at 23°C; the second stage ball milling speed is 340 rpm ball milling for 2 hours, the heat generated during the ball milling process will keep the second stage system temperature at 42°C; the third stage ball milling The rotation speed is 500 rpm ball milling for 2 hours, the heat generated during the ball milling process will keep the temperature of the third stage system at 57°C, and the ball milling product will be obtained after the ball milling is completed;

Step 3: Take out the ball milled product obtained in Step 2 and transfer it to the reactor, add 100 parts of water into the reactor within 25 minutes while stirring, cool down the temperature of the product in the reactor to 38°C, and then pour it into the reactor within 25 minutes Add 10 parts of hydrogen peroxide with a mass fraction of 30%, and the color of the system will turn bright yellow. Use a high-speed centrifuge at 10,000 to 15,000 rpm for 3 to 5 minutes. The lower layer of the centrifuge tube is graphene oxide precipitate, and the upper layer is Then pour off the supernatant of the centrifuge tube, then add deionized water to the position of the original supernatant in the centrifuge tube, stir evenly with a glass rod, and then repeat the centrifugal precipitation and washing until the washing liquid is filled with barium chloride solution The presence of sulfate radicals cannot be detected, and a few-layer graphene oxide dispersion is obtained.

The graphene oxide sheet prepared in this example has about 3 layers, a thickness of 2.75 nm, a specific surface area of 638 m ² /g, and an oxygen content of 28%.

Example 5:

Step 1: Mix concentrated sulfuric acid with a mass fraction of 98% and concentrated phosphoric acid with a mass fraction of 85% according to a mass ratio of 10:2 to obtain a strong acid solution, and then take 15 parts of the strong acid solution in parts by mass and add it to the reactor and The temperature of the control system is 12°C, and 1.5 parts of graphite powder with a particle size of 200-400 mesh and a carbon content of 90% to 99% and 4 parts of potassium permanganate with a particle size of 100 mesh and a purity greater than 99% are mixed while stirring. The mixture was added into the reactor within 17 minutes, and the temperature of the system was kept at 12° C. during the addition. After the addition, the temperature was maintained at 12° C. and continued to stir for 1 hour to obtain a reaction mixture;

Step 2: transfer the reaction mixture obtained in step 1 to the nylon material ball milling tank of the planetary ball mill, and start to carry out wet ball milling in three stages. 4mm, 6mm, 8mm, 10mm, 12mm, 15mm, the corresponding mass ratio is 15:20:25:30:35:40:45 stainless steel balls, the first stage ball milling speed is 125 rpm ball milling 1.5 hours, ball milling process The heat generated will keep the temperature of the first stage system at 28°C; the second stage ball milling speed is 350 rpm ball milling for 1.5 hours, the heat generated during the ball milling process will keep the second stage system temperature at 50°C; the third stage ball milling The rotation speed is 525 rpm ball milling for 2.5 hours, the heat generated during the ball milling process will keep the temperature of the third stage system at 50°C, and the ball milling product will be obtained after the ball milling is completed;

Step 3: Take out the ball milled product obtained in Step 2 and transfer it to the reactor, add 125 parts of water into the reactor within 27 minutes while stirring, cool down the product in the reactor to 36°C, and then pour it into the reactor within 23 minutes Add 7 parts of hydrogen peroxide with a mass fraction of 30%, and the color of the system will turn bright yellow. Use a high-speed centrifuge at 10,000 to 15,000 rpm for 3 to 5 minutes. The lower layer of the centrifuge tube is graphene oxide precipitate, and the upper layer is Then pour off the supernatant of the centrifuge tube, then add deionized water to the position of the original supernatant in the centrifuge tube, stir evenly with a glass rod, and then repeat the centrifugal precipitation and washing until the washing liquid is filled with barium chloride solution The presence of sulfate radicals cannot be detected, and a few-layer graphene oxide dispersion is obtained.

The graphene oxide sheet prepared in this example has about 2 layers, a thickness of 2.26 nm, a specific surface area of 784 m ² /g, and an oxygen content of 27%.

The following table is a comparison between the preparation method of the present invention and the traditional Hummers method.

Claims (10)

1. a preparation method of a few-layer graphene oxide dispersion liquid, is characterized in that, comprises the following steps: Step 1: Add 10-20 parts of strong acid into the reactor according to parts by mass and control the temperature of the system at 10-20°C. While stirring, add the mixture of 1-2 parts of graphite powder and 3-5 parts of permanganate into the reaction In the container, keep the temperature of the system at 10-20°C during the feeding process, and maintain the temperature at 10-20°C after the feeding is completed and continue to stir to obtain the reaction mixture; Step 2: transfer the reaction mixture obtained in step 1 to the ball mill tank of the ball mill, and start to carry out wet ball milling in three stages. The mass ratio of ball to material during ball milling is 300-400:1, and the ball milling speed in the first stage is 100-150 rpm; the second stage ball milling speed is 300-350 rpm; the third stage ball milling speed is 500-550 rpm, and the ball milling product is obtained after the ball milling is completed; Step 3: Take out the ball milling product obtained in Step 2 and transfer it to the reactor, add 100-150 parts of water into the reactor while stirring, cool down the product in the reactor to 35-40°C, and then add hydrogen peroxide 5 into the reactor ~10 parts, and finally the product was subjected to repeated centrifugal precipitation and washing until no sulfate radical was detected in the washing liquid with a barium chloride solution, that is, a few-layer graphene oxide dispersion liquid was obtained. 2. the preparation method of few lamellar graphene oxide dispersion liquid according to claim 1, is characterized in that, the strong acid described in step 1 is that concentrated sulfuric acid and concentrated phosphoric acid are mixed by the mass ratio of 10:2, wherein The concentration of concentrated sulfuric acid used is expressed as 98% by mass fraction, and the concentration of concentrated phosphoric acid used is expressed as 85% by mass fraction. 3. The preparation method of the few-lamellar graphene oxide dispersion according to claim 1, characterized in that the particle size of the graphite powder described in step 1 is 200-400 mesh, and the carbon content is 90%-99%. 4. the preparation method of few lamellar graphene oxide dispersion liquid according to claim 1 is characterized in that, the permanganate described in step 1 is potassium permanganate, sodium permanganate, lithium permanganate One of them, the particle size is 100 mesh, and the purity is greater than 99%. 5. the preparation method of few lamellar graphene oxide dispersion liquid according to claim 1, is characterized in that, the mixture of 1～2 parts of graphite powder and 3～5 parts of permanganate described in step 1 is in 15～ Add it into the reactor within 20 minutes, and the time for continuing stirring is 0.5 to 1 hour. 6. the preparation method of few-layer graphene oxide dispersion liquid according to claim 1, is characterized in that, ball mill described in step 2 is a planetary ball mill, and grinding ball is 2mm, 4mm, 6mm, 8mm, 10mm by diameter , 12mm, 15mm, and the corresponding mass ratio is 10～15:15～20:20～25:25～30:30～35:35～40:40～45 stainless steel balls, and the ball mill tank is made of nylon. 7. The preparation method of the few-layer graphene oxide dispersion liquid according to claim 1, characterized in that, the ball milling time of the first stage described in step 2 is 1 to 1.5 hours, and the ball milling time of the second stage is 1.5 to 2 hours. Hours, the third stage ball milling time is 2 to 2.5 hours. 8. The preparation method of the few-layer graphene oxide dispersion liquid according to claim 1, is characterized in that, in step 3, 100～150 parts of water are added to reactor in 25～30 minutes while stirring, and described The hydrogen peroxide is industrially pure, with a mass fraction of 30%, and the hydrogen peroxide is added to the reactor within 20 to 25 minutes. The mass fraction concentration of the barium chloride solution is 25%, which is prepared by dissolving analytically pure barium chloride in deionized water. 9. The preparation method of the few-lamellar graphene oxide dispersion according to claim 1, characterized in that, the operation process of repeated centrifugal precipitation and washing described in step 3 is to use a 10000-15000 rpm high-speed centrifuge Centrifuge and settle for 3 to 5 minutes. The lower layer of the centrifuge tube is the graphene oxide precipitate, and the upper layer is the supernatant. Then pour off the supernatant of the centrifuge tube, and then add deionized water to the position of the original supernatant in the centrifuge tube. Stir evenly, and then repeat the operation process of centrifugal precipitation and washing. 10. A few-layer graphene oxide dispersion liquid prepared according to the preparation method of claim 1, is characterized in that, the graphene oxide sheet layer≤3 layers in the prepared few-layer graphene oxide dispersion liquid, thickness is 1-3nm, sheet size 0.2-1.2μm, specific surface area 600-900m ² /g, oxygen content 25%-30%.