▎ 摘　　要

NOVELTY - Preparation method of graphene/bismuth telluride microwave absorbing composite material, involves (a) adding bismuth telluride powder and graphene oxide powder to the ethanol solution, stirring to obtain bismuth telluride ethanol solution and graphene oxide ethanol solution, mixing, ultrasonically treating, and stirring to form a stable colloidal solution, (b) reacting the colloidal solution, cooling, taking out the graphene oxide/bismuth telluride composite material filled with ethanol and replacing it with a water system, (c) freezing the above system to a solid state in liquid nitrogen, (d) freeze-drying the obtained solid composite of graphene oxide/bismuth telluride and ice to obtain dry graphene oxide/bismuth telluride composite material, (e) heating up in argon gas, heating the obtained dry composite material for heat treatment and reduction, and obtaining a graphene/bismuth telluride absorbing material, and (f) testing the reflectivity of the obtained absorbing material. USE - The method is used for preparation of high-performance graphene/bismuth telluride microwave absorbing composite material which is used in applications of military stealth, preferably in military fighter jets, missiles, and surface naval device (all claimed). The composite material is used in civil anti-electromagnetic radiation interference and military applications. ADVANTAGE - The method reduces the dielectric constant and refractive index of the obtained material by constructing a porous structure, reduces the surface reflection of incident electromagnetic waves, and enables most of the electromagnetic waves to be incident into the material. The method simultaneously ensures that the synergy between the graphene material and the loaded bismuth telluride is used to achieve a coordinated response to electromagnetic waves, and improving the absorption and attenuation of electromagnetic waves, and finally achieving high absorption intensity and broadband absorption of microwaves. The composite material has high-performance. DETAILED DESCRIPTION - Preparation method of high-performance graphene/bismuth telluride microwave absorbing composite material, involves (a) adding bismuth telluride powder and graphene oxide powder to the ethanol solution, vigorously stirring to obtain bismuth telluride ethanol solution and graphene oxide ethanol solution, mixing, ultrasonically treating, and stirring to form a stable colloidal solution, (b) transferring the obtained colloidal solution to a PTFE lining, putting the lining into a stainless steel reactor, reacting at 100-240 degrees C for 6-36 hours, naturally cooling to room temperature, taking out the graphene oxide/bismuth telluride composite material filled with ethanol and completely replacing it with a water system, (c) gradually freezing the above system to a solid state in liquid nitrogen, where the freezing temperature is -196 degrees C to 10 degrees C, (d) freeze-drying the obtained solid composite of graphene oxide/bismuth telluride and ice at -20 degrees C to 15 degrees C for 48-180 hours, to obtain dried graphene oxide/bismuth telluride composite material, (e) gradually heating up in argon gas, heating the obtained dry graphene oxide/bismuth telluride composite material at 200-600 degrees C for heat treatment and reduction for 0.5-6 hours, and finally obtaining a graphene/bismuth telluride absorbing material, and (f) testing the reflectivity of the obtained graphene/bismuth telluride absorbing material in the microwave frequency of 2-18 GHz.