▎ 摘　　要

NOVELTY - A composite thermoelectric film is prepared by preparing graphene powder, potassium persulfate and phosphorus pentoxide, adding concentrated sulfuric acid, forming mixture, regulating pH, heating, diluting with distilled water, placing, filtering with distilled water, regulating, and drying to dry mixture; and adding concentrated nitric acid, stirring, regulating pH, uniformly stirring, first adding potassium permanganate, stirring, cooling, second adding potassium permanganate, stirring, cooling, third adding potassium permanganate, stirring, and pre-oxidizing graphite to obtain mixture. USE - Method for preparing composite thermoelectric film. ADVANTAGE - The product has good electrical conductivity. The method is convenient. DETAILED DESCRIPTION - A composite thermoelectric film is prepared by: (A) preparing graphene powder, potassium persulfate and phosphorus pentoxide, adding concentrated sulfuric acid, forming mixture, regulating pH to 1.5, stirring at 60 degrees C for 1-2 hours, heating to 80 degrees C for 2-4 hours at speed of 5 degrees C/minute and 87 degrees C for 1-2 hours at speed of 2 degrees C/minute, diluting with distilled water to pH of 3.6, placing for 36 hours, filtering with distilled water, regulating pH to 6-7, and drying at room temperature to dry mixture; (B) adding concentrated nitric acid, stirring for 45-60 minutes, regulating pH to 2-4, uniformly stirring at - 8 degrees C, first adding potassium permanganate, stirring for 30 minutes, cooling to - 12 degrees C, second adding potassium permanganate, stirring for 30 minutes, cooling to - 15 degrees C, third adding potassium permanganate, stirring for 20 minutes, and pre-oxidizing graphite to obtain mixture; (C) entering into box, heating to 40 degrees C, reacting for 3 hours, first adding distilled water, heat preserving at 40 degrees C for 2.5 hours, second adding distilled water and hydrogen peroxide for 10-60 minutes, separating for 10 minutes at rotating speed of 9500 revolutions/minute (rpm), washing with hydrochloric acid solution, and dialyzing for 7-8 days to get graphite oxide; (D) putting into prepared purifying liquid, carrying out oscillation dispersing, filtering to obtain purified graphite oxide, ultrasonically dissolving using dimethylsulfoxide, adding N-hydroxysuccinimide and self-control surface processing agent at 35 degrees C for 2 hours, suction filtering, washing, and drying to obtain surface treated graphite oxide; (E) taking 1-2 g, freeze-drying at - 10-30 degrees C, ultrasonically dispersing with 1-10 g polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and mixture of 1 g polymethacrylate and polyacrylamide into 500 ml ethanediol, UV irradiating for 36 hours, and forming first dispersion liquid; (F) taking 4-15 g iron(III) chloride hexahydrate, iron(II) chloride tetrahydrate and iron(III) acetylacetonate mixture, 6-25 g polyvinylpyrrolidone and 10-50 g ammonium acetate, dissolving into 500-1000 mL ethanediol, forming second dispersion liquid, adding first dispersion liquid, stirring, and adjusting pH through ammonia to 8-10 to clear solution; (G) taking 100 ml clear solution, putting into reaction kettle, sealing, heating to 150 degrees C for 2 hours, heating to 200 degrees C for 4 hours at rate of 2-4 degrees C/minute, heating to 235 degrees C for 3 hours at rate of 3-6 degrees C/minute, cooling to 200 degrees C for 2 hours at speed of 5-7 degrees C/minute, heating to 235 degrees C for 7 hours at rate of 3-6 degrees C/minute, taking out, cooling to room temperature rate of 3-6 degrees C/minute, taking black powder, separating for 10 minutes at speed of 8000-10000 rpm, washing with anhydrous ethanol and deionized water for 3 times, and drying to 50-70 degrees C for 24 hours to obtain first product; (H) taking 5 g, adding 5-10 g aniline monomer and sodium dodecylbenzenesulfonate, ultrasonically dispersing for 65 minutes, forming second product, dissolving 3 g ammonium sulfate into 80-120 ml distilled water, dropwise adding second product, stir reacting for 15 hours, washing with distilled water and alcohol, filtering, and vacuum drying at 50-70 degrees C for 24-36 hours to obtain wave-absorbing material; (I) adding deionized water to 5-25 g/L solution, machine stirring for 10-15 minutes, ultrasonically dispersing for 30-50 minutes under ultrasonic wave frequency of 30 Hz, forming uniform solution, and placing into container; and (J) selecting copper piece as substrate material, ultrasonically cleaning with acetone, deionized water, methanol and deionized water for 5-10 minutes, vacuum drying at 90-120 degrees C for 10-30 minutes, putting into container as cathode with iron piece as anode, regulating through regulating device for 30-90 minutes at constant voltage mode of 30-120 V. The mass ratio of graphene powder, potassium persulfate, phosphorus pentoxide and concentrated sulfuric acid is 1-3:1-2:1-2:5-1. The mass ratio of dry mixture and concentrated nitric acid is 1-4:50-100. The mass ratio of first adding potassium permanganate, second adding potassium permanganate and third adding potassium permanganate is 1:2:3. The ratio of dry mixture and potassium permanganate is 1-2:10-15. The ratio of second distilled water and hydrogen peroxide is 4-20. The purifying liquid comprises 1.72 g/ml concentrated sulfuric acid and hydrogen peroxide at mass ratio 1-2:2-5. The mass ratio of polymethacrylate and polyacrylamide is 1:1. The mass ratio of iron(III) chloride hexahydrate, iron(II) chloride tetrahydrate and iron(III) acetylacetonate is 1:1:0.5. The mass ratio of first product and sodium dodecylbenzenesulfonate is 1-1.5:8-15. An INDEPENDENT CLAIM is included for nanocomposite wave-absorbing material comprising nano-stratiform composite wave-absorbing material with uniformly growth hollow semi-spherical structure ferroferric oxide nanoparticle and reduced graphene sheet surface.