▎ 摘　　要

NOVELTY - Three-dimensional graphene/carbon nanotube composite material comprises honeycomb three-dimensional graphene frame and carbon nanotubes grown on the frame, where the carbon nanotubes are multi-walled carbon nanotubes with a tube diameter size of 10-100 nm, the three-dimensional graphene frame is assembled from a few layers of graphene in situ, and the number of layers is 2-8 layers, graphene and carbon nanotubes are connected by a covalent bond. USE - The composite material is useful in energy storage and catalysis. ADVANTAGE - The composite material: has good conductivity, large specific surface, high active material loading, stable electrochemical performance, short production cycle. The method is economical and suitable for industrial production; has strong repeatability. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing three-dimensional graphene/carbon nanotube composite material, comprising (i) dissolving ferric nitrate nonahydrate and polyvinylpyrrolidone (K30) in deionized water to obtain mixed solution, and grinding into powder after completely dried, (ii) placing the powder in tube furnace, heating to 150-250 degrees C in a protective atmosphere at a temperature increase rate of 3-5 degrees C/minute, and keep it warm for 0.5-1 hour, heating to 700-800 degrees C at heating rate of 4-6 degrees C/minute and kept warm for 1-2 hours, heating to 850-880 degrees C at a temperature increase rate of 3-5 degrees C/minute and kept warm for 2-3 hours, reducing temperature to 605-645 degrees C at cooling rate of 3-5 degrees C/minute, passing gas carbon source, cutting off the gas carbon source after holding for 0.5-2 hours, collecting the product after the furnace is cooled to room temperature, the product is a multi-walled carbon nanotube-coated iron carbide nanoparticle/three-dimensional graphene composite material or a multi-walled carbon nanotube-coated iron/iron carbide nanoparticle/three-dimensional graphene composite material, placing iron carbide nanoparticles/three-dimensional graphene composite material wrapped by multi-wall carbon nanotubes or the iron/iron carbide nanoparticles/three-dimensional graphene composite material wrapped by multi-wall carbon nanotubes in a high-temperature graphitization furnace, in argon atmosphere, heating to 2800-3000 degrees C at a heating rate of 5-8 degrees C/minute, and kept warm for 1-2 hours, cooling the high-temperature furnace to room temperature, collecting the product, which is three-dimensional graphene/carbon nanotube composite material.