Preparation method of stable graphene aqueous dispersion liquid

Abstract

The invention discloses a preparation method of a stable graphene water-based dispersion liquid, relates to the field of graphene water-based dispersion, and aims at solving the problems that an existing preparation method of the graphene water-based dispersion liquid is large in pollution, or influences graphene performance, or is high in cost and is not beneficial to industrial production. The preparation method comprises the following steps: adding graphene powder into an organic cosolvent, and fully dispersing the graphene powder in the organic cosolvent under an ice bath condition to obtain a primary graphene dispersion liquid; and carrying out solid-liquid separation on the primary graphene dispersion liquid to obtain a graphene filter cake, adding the filter cake into water, adding alcohol to adjust viscosity, and fully dispersing the filter cake at room temperature to obtain a stably dispersed graphene aqueous dispersion liquid. The method is simple, low in price and small in pollution, the dispersion liquid is not obviously settled after standing for three months, no impurity is generated after volatilization during use, and the method is suitable for industrial production popularization.

Description

technical field [0001] The invention relates to the field of graphene aqueous dispersion, in particular to a preparation method of a stable graphene aqueous dispersion. Background technique [0002] As an advanced carbon nanomaterial, graphene is a two-dimensional material with only atomic thickness; the unique atomic structure makes graphene have excellent electrical conductivity and high charge carrier mobility (20m 2 V -1 the s -1 ), at the same time, it also has a high specific surface area (2630m 2 g -1 ), excellent mechanical, electrical, thermal and optical properties, high specific surface area and unique atomic structure, therefore, it has been widely studied and applied in many fields such as electrochemical energy storage, environmental protection, biomedicine, and electronic equipment. [0003] At present, the preparation and processing of graphene are two key issues in the application process of graphene. The reliable method of preparing graphene that has b...

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Problems solved by technology

The reliable method of preparing graphene that has been reported has the mechanical exfoliation of graphite, epitaxy or chemical vapor deposition (CVD) growth, redox method prepares graphene oxide, the liquid phase exfoliation of graphite etc.; The suitable organic solvent of reported such as N- Methyl-2-pyrrolidone and N,N-dimethylformamide have disadvantages such as high toxicity, high cost, high boiling point, and incompatibility with other processing aspects. Therefore, the development of graphene aqueous dispersion system has very good prospects; However, graphene has poor dispersibility in water and cannot meet the actual needs. For this, the methods commonly used in this field include adding stabilizer surfactants or polymers to achieve stable dispersion.

[0004] For example, the publication number is CN109896521A, a patent application for a stable graphene dispersion and its preparation method and application, which discloses the use of aromatic ring macromolecular polymers with sulfonic acid groups or sulfonyl groups through The π-π bond interaction realizes the stable dispersion of the graphene aqueous solution, which can obtain a dispersion liquid that has been dispersed for more than three months. However, the addition of polymers will inevitably affect the excellent electrical and thermal conductivity of graphene. The influence; publication number is CN110330012A, and the name is called the invention patent application of the preparation method of high-concentration graphene aqueous dispersion liquid and self-dispersing graphene powder, wherein discloses using carboxymethylcellulose potassium etc. as dispersant, and it can be in The aqueous dispersion of graphene is realized in the inorganic salt solution, but it uses a surfactant as a dispersant, which is difficult to remove in subsequent use, and has a greater impact on the performance of graphene; the publication number is CN110655596A, and the name is star-shaped cationic graphite The invention patent application of olefin dispersant and its application discloses the use of star-shaped cationic graphene dispersant to prepare a stably dispersed graphene aqueous solution, which can utilize the star-shaped polymer topology to obtain a stably dispersed graphene aqueous solution, but this The preparation of dispersants involves complex organic reactions, the preparation process is cumbersome, the pollution is serious, and the utilization rate of graphene is low

[0005] After adding polymers or surfactants to graphene, even if stable dispersion can be achieved, it can only be used as a composite later, and the high-quality performance of graphene will be lost; , it is very necessary and important to disperse graphene directly in a low-cost, low-boiling solvent, especially in an aqueous solution. Therefore, a method for preparing a stable graphene aqueous dispersion is urgently needed to solve this problem

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