Graphene dispersion liquid and preparation method

Abstract

The application discloses a graphene dispersion liquid and a preparation method thereof, relates to the field of graphene dispersion liquid and a preparation method thereof, and aims at solving the technical problem that it is difficult to obtain a high-concentration stable graphene dispersion liquid at present. In the dispersion liquid, graphene is obtained by reduction of graphene oxide prepared by a Hummers method, and then is uniformly dispersed into N-methyl pyrrolidone under the assistance of dispersants of sodium polystyrene sulfonate and polydiallyldimethylammonium chloride. The application is used for preparing the graphene dispersion liquid.

Description

Technical Field

[0001] This invention relates to the field of graphene dispersions and their preparation methods. Background Technology

[0002] Graphene, a novel material, is one of the strongest known materials. Its carrier mobility at room temperature is approximately 15000 cm² / (VS), more than 10 times that of silicon. Simultaneously, graphene possesses excellent thermal conductivity; pure, defect-free monolayer graphene has a thermal conductivity as high as 5300 W / mK. Due to its unique physicochemical properties in electrical, mechanical, and optical aspects, graphene has become a hot topic in nanomaterial development. However, graphene nanomaterials are neither oleophilic nor hydrophilic, and due to van der Waals forces, they are prone to aggregation, making it difficult to maintain stable dispersion in solution for extended periods. This significantly limits the applications of graphene, making the preparation of high-concentration, stable graphene dispersions a pressing problem to be solved. Summary of the Invention

[0003] The present invention aims to solve the technical problem of obtaining high-concentration and stable graphene dispersions, and provides a graphene dispersion and its preparation method.

[0004] A graphene dispersion in which the graphene is obtained by reducing graphene oxide prepared by the Hummers method, and then uniformly dispersed in N-methylpyrrolidone with the aid of sodium polystyrene sulfonate and polydiallyl dimethyl ammonium chloride.

[0005] A method for preparing a graphene dispersion, specifically comprising the following steps:

[0006] 1. Graphene oxide was prepared from graphite using the Hummers method, then dispersed in water, subjected to ultrasonic treatment, filtered, and dried to obtain graphene oxide.

[0007] 2. The graphene oxide obtained in step 1 is reduced by hydrogen gas to obtain graphene.

[0008] 3. Add the graphene obtained in step 2 to N-methylpyrrolidone, then add sodium polystyrene sulfonate and polydiallyl dimethyl ammonium chloride, and process with an ultrasonic cell disruptor to obtain a slurry;

[0009] Fourth, the slurry obtained in step three is subjected to ultrasonic treatment to obtain the graphene dispersion.

[0010] Beneficial effects of this invention:

[0011] This invention uses the Hummers method to prepare graphene oxide, and then uses hydrogen reduction to obtain high-purity graphene, thus ensuring the quality of graphene in the graphene dispersion.

[0012] This invention uses N-methylpyrrolidone as a dispersant, and adds sodium polystyrene sulfonate and polydiallyl dimethyl ammonium chloride as co-dispersants, resulting in a homogeneous, stable, and high-concentration graphene dispersion.

[0013] This invention is used to prepare graphene dispersions. Detailed Implementation

[0014] Specific Implementation Method 1: This implementation method provides a graphene dispersion in which the graphene is obtained by reducing graphene oxide prepared by the Hummers method, and then uniformly dispersed in N-methylpyrrolidone under the aid of sodium polystyrene sulfonate and polydiallyl dimethyl ammonium chloride.

[0015] Specific Implementation Method Two: This implementation method provides a method for preparing a graphene dispersion, which is specifically carried out according to the following steps:

[0016] 1. Graphene oxide was prepared from graphite using the Hummers method, then dispersed in water, subjected to ultrasonic treatment, filtered, and dried to obtain graphene oxide.

[0017] 2. The graphene oxide obtained in step 1 is reduced by hydrogen gas to obtain graphene.

[0018] 3. Add the graphene obtained in step 2 to N-methylpyrrolidone, then add sodium polystyrene sulfonate and polydiallyl dimethyl ammonium chloride, and process with an ultrasonic cell disruptor to obtain a slurry;

[0019] Fourth, the slurry obtained in step three is subjected to ultrasonic treatment to obtain the graphene dispersion.

[0020] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method Two in that the ultrasonic dispersion power in step one is 200–500W, and the ultrasonic frequency is 20–40kHz. Everything else is the same as in Specific Implementation Method Two.

[0021] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method Two or Three in that the drying temperature in step one is 80-85℃. Everything else is the same as in Specific Implementation Method Two or Three.

[0022] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods Two to Four in that the hydrogen flow rate in step two is 200–300 sscm, and the reduction temperature is 500–600°C. Everything else is the same as in Specific Implementation Methods Two to Four.

[0023] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods Two to Five in that the mass-to-volume ratio of graphene to N-methylpyrrolidone in step three is (0.1-2) g: 10 mL. Everything else is the same as in Specific Implementation Methods Two to Five.

[0024] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods Two to Six in that the total mass ratio of sodium polystyrene sulfonate and polydiallyl dimethyl ammonium chloride to graphene in step three is 1:(0.1-20). Everything else is the same as in Specific Implementation Methods Two to Six.

[0025] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods Two to Seven in that the mass ratio of sodium polystyrene sulfonate to polydiallyldimethylammonium chloride in step three is 1:(0.5-2). Everything else is the same as in Specific Implementation Methods Two to Seven.

[0026] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods Two to Eight in that: in step three, the power of the ultrasonic cell disruptor is controlled to be 200–400W, the frequency to be 20–25KHz, and the processing time to be 20–30 minutes. Everything else is the same as in Specific Implementation Methods Two to Eight.

[0027] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods Two to Nine in that: in step four, the ultrasonic processing power is controlled to be 200–500W, the ultrasonic frequency to be 20–80KHz, and the processing time to be 30–60min. Everything else is the same as in Specific Implementation Methods Two to Nine.

[0028] The scope of this invention is not limited to the above-described embodiments; a combination of one or more specific embodiments can also achieve the purpose of the invention.

[0029] Example 1:

[0030] This embodiment describes a method for preparing a graphene dispersion, which is specifically carried out according to the following steps:

[0031] 1. Graphene oxide was prepared from graphite using the Hummers method. Then, 10g of graphene oxide was dispersed in 800mL of water and subjected to ultrasonic treatment. The ultrasonic dispersion power was controlled at 200W and the ultrasonic frequency at 30KHz for 30min. After filtration, the solution was dried at 80℃ for 4h to obtain graphene oxide.

[0032] 2. The graphene oxide obtained in step 1 is reduced by hydrogen gas. The flow rate of hydrogen gas is controlled at 200 sccm and the reduction temperature is controlled at 600℃ to obtain graphene.

[0033] 3. Add 100mg of graphene obtained in step 2 to 100mL of N-methylpyrrolidone, then add 100mg of sodium polystyrene sulfonate and 100mg of polydiallyl dimethyl ammonium chloride, and process with an ultrasonic cell disruptor. The ultrasonic cell disruptor has a power of 200W, a frequency of 25KHz, and a processing time of 20min to obtain a slurry.

[0034] Fourth, the slurry obtained in step three is subjected to ultrasonic treatment. The power of the ultrasonic cell disruptor is controlled at 300W, the frequency at 20KHz, and the treatment time is 30min to obtain the graphene dispersion.

[0035] The graphene dispersion prepared in this embodiment is homogeneous and stable, with a concentration of 0.8–1.2 g / L.

Claims

1. A method for preparing a graphene dispersion, characterized in that... This method is specifically carried out in the following steps:

1. Graphene oxide was prepared from graphite using the Hummers method, then dispersed in water, subjected to ultrasonic treatment, filtered, and dried to obtain graphene oxide.

2. The graphene oxide obtained in step 1 is reduced by hydrogen gas to obtain graphene.

3. Add the graphene obtained in step 2 to N-methylpyrrolidone, then add sodium polystyrene sulfonate and polydiallyl dimethyl ammonium chloride, and process with an ultrasonic cell disruptor to obtain a slurry; Fourth, the slurry obtained in step three is subjected to ultrasonic treatment to obtain the graphene dispersion. The total mass ratio of sodium polystyrene sulfonate and polydiallyl dimethyl ammonium chloride to graphene in step three is 1:(0.1-20). The mass ratio of sodium polystyrene sulfonate to polydiallyldimethylammonium chloride in step three is 1:(0.5-2).

2. The method for preparing a graphene dispersion according to claim 1, characterized in that... The ultrasonic treatment described in step one has a power of 200–500W and an ultrasonic frequency of 20–40KHz.

3. The method for preparing a graphene dispersion according to claim 1, characterized in that... The drying temperature described in step one is 80-85℃.

4. The method for preparing a graphene dispersion according to claim 1, characterized in that... The hydrogen flow rate in step two is 200–300 sccm, and the reduction temperature is 500–600℃.

5. The method for preparing a graphene dispersion according to claim 1, characterized in that... The mass-to-volume ratio of graphene to N-methylpyrrolidone in step three is (0.1-2) g: 10 mL.

6. The method for preparing a graphene dispersion according to claim 1, characterized in that... Step 3: Control the power of the ultrasonic cell disruptor to 200-400W, the frequency to 20-25KHz, and the processing time to 20-30min.

7. The method for preparing a graphene dispersion according to claim 1, characterized in that... Step four: Control the ultrasonic processing power to be 200-500W, the ultrasonic frequency to be 20-80KHz, and the processing time to be 30-60min.