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Preparation method for graphene

A graphene and graphene dispersion technology, applied in the field of graphene, can solve problems such as slow stripping efficiency, high equipment parameter requirements, metal shedding of ultrasonic probes, etc., achieve high hydraulic shearing effect, improve stripping efficiency, and improve The effect of production efficiency

Inactive Publication Date: 2018-03-27
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, the preparation of graphene by ultrasonic exfoliation has the following disadvantages: the exfoliation efficiency is slow, and the single treatment time usually reaches more than 10 hours; the yield is low, and the yield of one treatment is only about 10%; During the process, cavitation will cause the metal of the ultrasonic probe to fall off and pollute the material
However, the preparation of graphene by supercritical fluid exfoliation requires ultra-high pressure and temperature, which requires high equipment parameters and high equipment costs.

Method used

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preparation example Construction

[0022] The method for preparing graphene provided by the present invention comprises dispersing layered graphite in a solvent, and then making the resulting dispersion flow through microchannels to carry out high-pressure extrusion processing, and the pressure at the feed end of the high-pressure extrusion processing is higher than that at the discharge end. The pressure is at least 1 MPa to obtain a graphene dispersion.

[0023] The type of the solvent is not particularly limited in the present invention, and it can be various existing inert liquid substances capable of dispersing, such as existing various alcohol solvents, ester solvents, ether solvents, Amide solvents, water, etc., but in order to facilitate the solvent to enter between graphite layers through wetting to promote the exfoliation of graphene, preferably, the solvent is selected from N-methylpyrrolidone, dimethylformamide, At least one of dimethylacetamide, alcohol, acetone, water, toluene, xylene, methyl acet...

Embodiment approach

[0026] According to a preferred embodiment of the present invention, the preparation method of graphene also includes before carrying out high-pressure extrusion processing, the mixture of layered graphite, solvent and optional dispersant is stirred at high speed (stirring rate is 10- 20000 rpm) to a viscosity of 10-10000cP.

[0027] According to the method for preparing graphene provided by the present invention, the purpose of making the dispersion liquid flow through the microchannel is to generate a strong peeling impact force to peel the graphene from the layered graphite. According to a preferred embodiment of the present invention, the microchannel is at least one of a sandwich microchannel, a tubular microchannel and an Oreo microchannel.

[0028] Such as Figure 4 and Figure 5 As shown, the sandwich-type microchannel includes an upper baffle layer, a middle fluid layer and a lower baffle layer, and the dispersion liquid is introduced into the middle fluid layer fro...

Embodiment 1

[0039] This embodiment is used to illustrate the method for preparing graphene provided by the present invention.

[0040] (1) Formulation:

[0041] The composition and weight ratio of the formula used in this embodiment are as follows: graphite worm (also known as expanded graphite, purchased from Yichang Xincheng Graphite Co., Ltd., trade mark is Kp80, the same below) 100 parts, PVP (polyvinylpyrrolidone, molecular formula (C 6 h 9 NO) n, number average molecular weight is 1000) 10 parts, alcohol (ethanol, molecular formula C 2 h 5 OH, the concentration is 95% by weight) 1000 parts.

[0042] (2) Preparation of graphene:

[0043] ①Heat the alcohol water bath to 50°C, and add PVP into the alcohol in two batches under magnetic stirring. Graphite worms are added to the alcohol solution of PVP, and the stirring is continued until the viscosity is 10000cP to obtain a dispersion. ② Pressurize the dispersion liquid to 80MPa through a high-pressure pump, and squeeze it through ...

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Abstract

The invention specifically relates to a preparation method for graphene, belonging to the field of graphene. The method comprises the following steps: dispersing lamellar graphite in a solvent; and then allowing obtained dispersion to pass through a microchannel for high-pressure extrusion treatment so as to obtain graphene dispersion, wherein pressure at the feed end of the high-pressure extrusion treatment is at least 1 MPa higher than pressure at the discharge end of high-pressure extrusion treatment. The method not only can effectively peel lamellar graphite, but also can improve the production efficiency of the graphene; the method is simple and efficient, has low requirements on equipment, and is an ideal method for large-scale preparation of the graphene; in addition, the method does not need cavitation effect generated by vibration of an ultrasonic probe for realization of peeling and dispersion, so no metal impurity is generated, and the method has great industrial applicationprospects.

Description

technical field [0001] The invention relates to the field of graphene, in particular to a method for preparing graphene. Background technique [0002] Graphene is single-layer or few-layer graphite, which is the basic unit of layered graphite. Thousands of graphene layers in layered graphite are combined into one by intermolecular van der Waals forces. The van der Waals force between graphite layers is relatively weak, and the graphite layer can be opened by external energy to obtain single-layer or few-layer graphene. [0003] At present, the methods for preparing graphene mainly include physical and chemical methods. Among them, physical methods include mechanical exfoliation, liquid phase exfoliation, and direct growth methods, and chemical methods include redox methods, organic synthesis, and solvothermal synthesis. The liquid phase stripping method is divided into ultrasonic stripping and supercritical fluid stripping. The main method of ultrasonic exfoliation is as...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/19
CPCC01B2204/22C01P2004/04
Inventor 林信平任茂林吴猛祥孙荣严王文韬周松林文熹杨剑卫
Owner BYD CO LTD