Preparation method and application of nitrogen-doped graphene/nitrogen-doped carbon nanotube/zinc cobaltate composite material

Abstract

The invention discloses a preparation method of a nitrogen-doped graphene / nitrogen-doped carbon nanotube / zinc cobaltite composite material. The method comprises the following specific steps: (a) adding potassium permanganate, hydrochloric acid and hydrogen peroxide to graphene oxide, and carrying out a stirring reaction to obtain porous graphene; (b) dialyzing the porous graphene for 8-12 days, carrying out ultrasonic dispersion, then adding a carbon nanotube, carrying out ultrasonic mixing and carrying out suction filtration to form a film; (c) drying the film, and then adding ammonium hydroxide for reaction for 24 hours; (d) adding zinc nitrate, cobalt nitrate, urea, ammonium fluoride, absolute ethyl alcohol and distilled water for reaction for 4 hours; and (e) transferring a mixture to a tube furnace, and sintering the mixture in a nitrogen atmosphere for 2 hours, so as to obtain the composite material. The composite material has relatively good flexibility; the electrochemical properties are barely changed after the composite material is bent into various angles; the specific capacitance value of the composite material can be up to 1802F / g; compared with relatively simple graphene, the carbon nanotube and most of composite materials of the graphene and the carbon nanotube, the composite material provided in the invention are significantly improved.

Description

technical field [0001] The invention belongs to the field of electrochemistry, in particular to a preparation method and application of a nitrogen-doped graphene / nitrogen-doped carbon nanotube / zinc cobaltate composite material. Background technique [0002] Graphene is the thinnest and hardest known in the world nanomaterials , the thickness is only one carbon atom, and the specific surface area is as high as 2630m 2 / g, because the graphene-supported metal oxide or sulfide nanocomposite material can be used as the electrode material of electrochemical energy storage devices such as lithium-ion batteries, supercapacitors, and lithium-air batteries, which can significantly improve the charge / ion transport capacity of electrode materials , thereby improving the cycle stability of the electrode material. However, the reported metal oxides or sulfides supported on the surface of graphene mainly exist in the form of fine nanoparticles, with relatively low specific surface area,...

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Problems solved by technology

[0004] In the existing graphene-supported zinc cobalt oxide technology, the stacking between graphene sheets is limited, so the overall volume utilization rate is low, such as Dr. Gao Guoxin, Professor Ding Shujiang, and Nanyang Technological University, Singapore. The synthesis method of graphene-supported ultra-thin nickel cobaltate nanosheets researched by Professor Xiong Wen (David) Lou of the University ("Zinc Cobaltate Nanostructures Supported on Graphene Surface") uses sodium citrate as the material. During the preparation process Failed to reduce the stacking of graphene, and the materials it studied were applied to lithium-ion batteries, and no further research was done on supercapacitors; the Chinese patent application number 201310390188.0 disclosed a method for preparing nitrogen by molten salt casting method The method of doping graphene / nitrogen-doped carbon nanotubes / cobalt tetroxide composite paper material, the obtained composite material has ORR electrocatalytic performance, but its preparation method steps are complicated, have higher operation requirements, are not suitable for large-scale application, and The literature also does not involve supercapacitor research

At present, the preparation method of combining graphene, carbon nanotubes and zinc cobaltate to form a three-dimensional nanoarray structure as a supercapacitor material has not been reported yet.

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