A kind of cobalt phosphide/graphene/n-doped carbon composite material and preparation method thereof

Abstract

The invention discloses a cobalt phosphide / graphene / N-doped carbon composite material. The cobalt phosphide / graphene / N-doped carbon composite material has the advantages that cobalt phosphide is usedas the innermost layer of the cobalt phosphide / graphene / N-doped carbon composite material, N-doped carbon layers wrap the cobalt phosphide, graphene is used as the outermost layer of the cobalt phosphide / graphene / N-doped carbon composite material and wraps the N-doped carbon layers, and the cobalt phosphide / graphene / N-doped carbon composite material can become a three-dimensional conductive network structure by the aid of graphene layers; the polyhedron morphology of metal organic framework complexes can be effectively kept by the cobalt phosphide / graphene / N-doped carbon composite material, composition can be carried out on the graphene to form the three-dimensional conductive network structure, accordingly, products are high in crystallinity, electric storage capacity and porosity, long in service life and excellent in lithium storage property, and have large specific surface areas, and the purity of the products can reach 99%; the discharge capacity of the products is 702.11 mAh g<-1> after 100 charge-discharge cycles under the condition of the current density of 100 mA g<-1>, the lithium storage properties can be prevented from being attenuated, and the capacitance of the products can be prevented from being attenuated after 200 charge-discharge cycles at most; the cobalt phosphide / graphene / N-doped carbon composite material is good in stability in use procedures, unstable current conditions can be prevented, a method for preparing the cobalt phosphide / graphene / N-doped carbon composite material is high in yield, the yield can reach 70% at least, processes for preparing the cobalt phosphide / graphene / N-doped carbon composite material are simple and feasible, and accordingly the cobalt phosphide / graphene / N-doped carbon composite material is worthy of being promoted on markets.

Description

technical field [0001] The invention relates to the technical field of new materials, in particular to a cobalt phosphide / graphene / N-doped carbon composite material and a preparation method thereof. Background technique [0002] With the depletion of fossil energy represented by oil and the increasingly serious environmental pollution caused by the combustion of fossil energy, people urgently need a sustainable, renewable and clean energy. Lithium-ion batteries stand out from many new energy sources due to their high energy density, long cycle life, and environmental friendliness, and are widely used in mobile electronic devices, new energy vehicles, and other fields. However, the negative electrode material of commercial lithium-ion batteries is graphite, and the theoretical capacity of graphite is only 372mAh / g, which cannot meet the capacity requirements of large electronic equipment such as electric vehicles, which limits the application and development of lithium-ion ba...

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Problems solved by technology

[0005] So far, cobalt phosphide / graphene / N-doped carbon composites still have graphene that cannot be composited. Graphene is dispersed in the system and cannot form a three-dimensional conductive network structure. The output is low, and the crystallinity of the total product is low. Technical problems such as small capacitance, short cycle life, poor stability during use, and prone to sudden large and small currents need to be solved urgently

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