Method for preparing high-purity graphene

Abstract

The invention provides a method for preparing high-purity graphene. The method comprises the following steps: (1) respectively grinding and screening graphite to obtain graphite powder having an average grain diameter of 210-480mu m; (2) weighing the graphite powder and an oxalic acid solution in a weight ratio of 1:1.5-1:5 to prepare a carboxylated graphene turbid solution; (3) putting the carboxylated graphene turbid solution in an ultrasonic device for ultrasonic oscillation to obtain a carboxylated graphene suspension; (4) adding a zinc salt solution into the carboxylated graphene suspension, and stirring to obtain a mixed solution of zinc salt and carboxylated graphene; filtering the mixed solution, carrying out microwave heating and activating treatment on the filtered substances, cooling, pickling, washing, filtering and drying to obtain graphene. The method is low in material cost, simple in manufacture process and convenient for large-scale production, and the prepared graphene has a relatively high specific surface area.

Description

technical field [0001] The invention relates to the field of graphene material preparation, in particular to a high-purity preparation method of graphene. Background technique [0002] Graphene was first prepared in 2004 by Andre K. Geim of the University of Manchester, UK, and its unique properties make it widely used in more and more industries. For example, the tensile strength of graphene is as high as 125GPa, the modulus of elasticity reaches 1.1TPa, and the theoretical specific surface area can reach 2630m 2 / g, thermal conductivity at room temperature is about 5000W / mK, etc., which make it have the prospect of application as a thermal conductive material; moreover, single-layer graphene is highly transparent and only absorbs 2.3% of visible light, so it also has applications in the field of optical lighting condition. [0003] So far, there are multiple known methods for preparing graphene, such as: (1) micromechanical exfoliation. This method can only produce a ve...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the yield is very low, which limits its commercial application; (5) oxidation-reduction method

This method is the simplest and common method to obtain graphene in large quantities. The more commonly used reduction methods are chemical reduction (hydrazine hydrate, ethylenediamine, sodium borohydride, etc. as reducing agents) and rapid thermal reduction, but various methods of reduction Finally, there will be a process of agglomeration of graphene, resulting in a small specific surface area of ​​graphene, generally less than 900m 2 / g

Moreover, the existing graphene preparation method makes its manufacturing cost high and directly limits its widespread use in the field of LED lighting, resulting in excessive cost pressure for LED lighting.