▎ 摘　　要

NOVELTY - A graphene composite nanometal film comprises alternately stacked graphene composite nanometal film layers (A) and (B). The thickness of the graphene composite nanometal film is 100-500 mu m. The graphene composite nanometal film layer (A) comprises two-dimensional layered graphene nanosheets with a thickness of 5-10 nm, aluminum oxide hollow spheres with a particle size of 20-40 nm, and a surface with a microporous structure having a thickness of 20-50 mu m. The graphene composite nanometal film layer (B) comprises three-dimensional honeycomb graphene with an average diameter of 30-40 nm, aluminum oxide hollow spheres with a particle diameter of 20-40 nm, and a surface with a microporous structure having a thickness of 30-60 mu m. USE - The graphene composite nano metal film is useful in wave-absorbing material (claimed). ADVANTAGE - The graphene composite nano-metal film: has multilayer stack structure design, which combines low-size and medium-size alternately, excellent performance characteristics, oxidation resistance, high temperature resistance and absorption function; can achieve full-wavelength absorption; is easy to realize impedance matching; and can overcome the defects of metal wave-absorbing agent when used at high temperature. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the graphene composite nanometal film, which involves: (S1) dissolving phloroglucinol and terephthalaldehyde in water at 60-80 degrees C, continuously stirring and reacting for 0.5-2 hours to obtain a prepolymer solution, adding the prepolymer solution to a sealed hydrothermal kettle, hydrothermally treating at a predetermined hydrothermal temperature for 20-26 hours, drying the resulting product under vacuum at 50-120 degrees C for 24-30 hours to obtain polymer nanospheres, and carbonizing at 700-900 degrees C for 4-6 hours in an inert gas protective atmosphere to obtain a microporous carbon ball template; (S2) adding aluminum chloride to a mixed solvent of absolute ethanol/water to prepare a predetermined concentration of aluminum chloride/ethanol mixed solution, adding the microporous carbon ball template, stirring, ultrasonically treating, then adding carbamide, stirring in a water bath at 50-70 degrees C for 20-30 hours, suction filtering, drying, calcining, removing the microporous carbon ball template to obtain aluminum oxide hollow spheres with a microporous structure on the surface, and modifying the aluminum oxide hollow spheres with stearic acid to obtain modified nano-aluminum oxide hollow spheres; (S3) preparing a two-dimensional layered graphene nanosheet dispersion and a modified nano-aluminum oxide hollow sphere dispersion, mixing, then ultrasonically dispersing to obtain a mixed dispersion (A), spraying the mixed dispersion (A) on a receiving substrate using electrospraying process, and drying to obtain the graphene composite nanometal film layer (A) with a thickness of 20-50 mu m; (S4) separately preparing a three-dimensional honeycomb graphene dispersion and the modified nano-aluminum oxide hollow sphere dispersion, mixing, then ultrasonically dispersing to obtain a mixed dispersion (B), spraying the mixed dispersion (B) on the receiving substrate deposited with the graphene nanometal film (A) using electrospraying process, drying, and loading the graphene nanometal film (A) to obtain the graphene composite nanometal film (B) with a thickness of 30-60 mu m; and (S5) repeating the electrospraying process in steps (S3) and (S4).