Reduced graphene oxide-based hollow Co-MOF composite flexible electrode material and preparation method thereof

Abstract

The invention belongs to the technical field of electrode material preparation, and particularly relates to a reduced graphene oxide-based hollow Co-MOF composite flexible electrode material and a preparation method thereof. A graphene oxide-based Co-MOF composite material is obtained through freeze drying, then the graphene oxide-based Co-MOF composite material is rapidly reduced with a hot ammonium sulfide solution and etched to be hollow, and freeze-drying is performed again to obtain the reduced graphene oxide based hollow Co-MOF composite flexible material. The characteristics of high specific capacity of the Co-MOF derivative and excellent mechanical performance and high conductivity of the reduced graphene oxide are fully exerted, the prepared composite material can effectively buffer volume expansion in the circulation process, meanwhile, a hollow structure formed by Co-MOF further shortens an ion transmission path, electrochemical reaction kinetics is improved, and the material has obvious advantages.

Description

Technical field: [0001] The invention belongs to the technical field of electrode material preparation, and in particular relates to a reduced graphene oxide-based hollow Co-MOF composite flexible electrode material and a preparation method thereof. Background technique: [0002] The information disclosed in this background section is only intended to increase some understanding of the general background of the disclosure, and is not necessarily to be taken as an acknowledgment or any form of suggestion that the information constitutes prior art that is already known to those skilled in the art. [0003] In recent years, carbon-based composites have been widely researched and applied in electrode materials for energy storage devices due to their large specific surface area and good buffer properties. Among them, graphene is an excellent self-buffering framework material, and its three-dimensional self-buffering network can make the material have more active sites, high condu...

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Problems solved by technology

[0004] In the prior art, the method for preparing rGO-based (graphene-based) composite materials usually needs to be prepared by complex high-temperature heating (generally requires 120-180 degrees Celsius, 1-12h) and other processes, such as hydrothermal method; therefore requires more time and energy consumption

The graphene-based composite membrane material obtained by suction filtration usually takes a long time, and the graphene sheets are stacked severely, resulting in a poor three-dimensional network structure, which leads to a greatly reduced rate performance in battery tests

Moreover, the traditional slurry coating method needs to add conductive agents and binders when preparing electrodes, which undoubtedly reduces the energy density of the battery.

[0005] As a metal compound, MOF and its derivatives have attracted attention for their porous framework structure and high theoretical capacity, but their large volume expansion during cycling limits their applications.

[0006] Therefore, compounding MOF materials with graphene and combining the advantages of the two has become a trend in the field of materials. However, the previous methods of preparing graphene-based composite materials usually require complex steps such as high-temperature heating, which consumes a lot of energy and requires longer time

At the same time, the obtained graphene-based composite materials often have problems such as serious stacking of graphene sheets, resulting in poor three-dimensional network structure.

[0007] In addition, most of the applications of Co-MOF only stay at the stage of porous framework of its derivatives, so a new electrode form is needed to solve the above problems

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