A kind of functionalized porous graphene and preparation method thereof

Abstract

The invention belongs to the field of graphene materials and discloses functionalized porous graphene and a preparation method thereof. According to the method, a two-electrode electrolysis system isformed by using a mixed solution of phytic acid and ammonium sulfate as an electrolyte, graphite foil as an anode and a platinum sheet as a cathode; a direct-current power supply is used for providingdirect-current bias for the anode, the graphite foil of the anode expands and peels off to form graphene under the action of the bias, and graphene is released into the electrolyte; the electrolyte is ultrasonically processed and then filtered for impurity removal, an obtained filtrate is centrifuged, a supernatant is taken, a functionalized porous graphene suspension is obtained and filtered finally, and functionalized porous graphene is obtained. Porous graphene with the vacancy defect can be formed by using phytic acid as the electrolyte, and functionalized porous graphene can be formed byintroducing oxygen-phosphorus functional groups; meanwhile, peeling off of the graphite foil can be promoted by ammonium sulfate, and graphene with fewer layers is prepared.

Description

technical field [0001] The invention belongs to the field of graphene materials, and more specifically relates to a functionalized porous graphene and a preparation method thereof. Background technique [0002] Graphene is a two-dimensional carbon material composed of a single layer of carbon atoms in a honeycomb arrangement. Due to its high electrical conductivity, excellent mechanical stability and large theoretical specific surface area, it is used as energy storage devices such as batteries, super Ideal electrode material for capacitors. [0003] However, taking thin-film micro-supercapacitors as an example, the widespread application of pure graphene-based micro-supercapacitors is limited by their relatively low capacity and energy density. This is due to the strong van der Waals force between the graphene layers, which makes the graphene sheets easy to stack and agglomerate, which hinders the electrolyte from entering the inner space of the electrode, reduces the ion ...

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Problems solved by technology

[0003] However, taking thin-film micro-supercapacitors as an example, the wide application of simple graphene-based micro-supercapacitors is limited by their relatively low capacity and energy density.

This is due to the strong van der Waals force between the graphene layers, which makes the graphene sheets easy to stack and agglomerate, which hinders the electrolyte from entering the inner space of the electrode, reduces the ion transmission efficiency and the effective specific surface area of ​​the electrode, and finally makes the graphene-based Poor performance of supercapacitors

[0004] Introducing a pore structure on the graphene basal surface can effectively solve this problem. At present, the methods for preparing porous graphene mainly include: catalytic oxidation method, by spreading a large number of catalyst particles on the graphene basal surface, and then directional oxidation of the catalyst attachment area, to obtain Porous graphene, this method requires multi-step operations, and it is easy to produce large cracks on the surface of the material; nanolithography, through high-energy laser etching, forms micropores on the surface of graphene, this method can produce uniform arrays Distributed pore structure, but the cost is high, which is not conducive to large-scale manufacturing; the direct heating method in the air heats the graphene powder at a certain temperature in the air atmosphere, and the amorphous region on the graphene basal surface preferentially reacts with oxygen to generate CO 2 escape to form a pore structure, this method is simple and easy, but it needs to prepare the finished graphene in advance, and it will inevitably oxidize the graphene in a large area

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