Graphene-based composite material as well as preparation method and application thereof

Abstract

The invention discloses a graphene-based composite material as well as a preparation method and application thereof. The method comprises the following steps: (1) mixing a manganese salt solution, a hydroxide solution and a solution containing a conductive carbon material to obtain a mixed slurry, carrying out suction filtration and washing on the mixed slurry, dispersing the mixed slurry in water, and carrying out spray drying on a dispersion liquid to obtain a precursor containing manganese hydroxide and the conductive carbon material; (2) putting the precursor into a high-temperature reactor, continuously heating, introducing protective gas, and introducing first gas containing protective gas and hydrogen into the high-temperature reactor after a first preset temperature is reached, soas to obtain manganese oxide containing a conductive carbon material; (3) putting the manganese oxide containing the conductive carbon material into a high-temperature reactor and continuously heating; and introducing protective gas at the same time, and introducing a second gas containing protective gas and a carbon source or containing the protective gas, the carbon source and a nitrogen sourceinto the high-temperature reactor after a second preset temperature is reached, so as to obtain graphene or nitrogen-doped graphene deposited on manganese oxide containing the conductive carbon material.

Description

technical field [0001] The invention belongs to the technical field of carbon materials, and in particular relates to a graphene-based composite material and its preparation method and application. Background technique [0002] The rapid development of the information industry in today's society has brought a huge market scale to the application of lithium-ion batteries. However, with the continuous progress of society, the society requires both high energy density, high volumetric energy density, high safety and low cost. The battery system shows higher desire. The existing lithium-ion batteries obviously cannot meet the above requirements. Therefore, the development of lithium-ion batteries with stronger performance has become an important goal of the majority of scientific researchers. [0003] Manganese oxide anode material has the advantages of high energy density, excellent cycle stability, and low material cost, and has become a hot anode material for current researc...

AI Technical Summary

Problems solved by technology

[0005] (1) It is difficult to prepare graphene on a large scale: the traditional oxidation-reduction method is limited by a long production cycle, a large amount of waste acid and waste liquid, and safety and environmental protection issues, while the reaction conditions of the epitaxial growth method are relatively harsh, and the single crystal silicon carbide substrate The cost is too high, graphene is difficult to separate from the substrate, and it is difficult to prepare graphene materials in large quantities, and the prospect of industrial production is not great

[0006] (2) Difficult to control the structure of graphene: the quality of graphene (mainly based on chemical redox method) which is widely used at present is not high, which is highlighted in the fact that the size of most graphene products is extremely uneven and the conductivity is not high enough. high

However, these methods still have scientific bottlenecks in terms of macro preparation, graphene layer number and lateral size control, and structural integrity.

[0007] (3) Insufficient performance of transition metal oxides: Although the theoretical capacity is high, transition metal oxides have poor electrical conductivity, high irreversible capacity, obvious volume effect during charge and discharge, and pulverization of electrode materials, resulting in poor cycle stability and low capacity. Fast attenuation and other issues restrict its industrial application

[0008] (4) The processing technology of graphene composites is immature: for the development of graphene composites, purposeful and controllable manipulation technology is crucial to optimize the performance of composite material systems in detail

[0009] Therefore, the existing technology for preparing graphene-based composites needs to be improved

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