▎ 摘　　要

NOVELTY - Preparation of graphene includes mixing graphite powder and ammonium chloride, adding to ball mill tank, adding grinding balls, and ball milling to obtain graphite mixture; adding to sealed vacuum reactor, vacuumizing, increasing temperature, spray cooling, heating, heat preserving, and repeating cycle; heating, injecting ultrasonic auxiliary agent, opening vent hole on top of reactor, venting gas, releasing vacuum, returning pressure to normal pressure, injecting condensed water, cooling reactor, turning on ultrasonic generator, and ultrasonically stripping graphene-containing suspension; and pumping, centrifugally concentrating to obtain high graphene content aqueous paste, or filtering to remove aqueous solution, or directly centrifuging, water washing or freeze-drying. USE - Method for preparation of graphene. ADVANTAGE - The method is simple, convenient and fast, completely decomposes and converts ammonium chloride intercalation agent to gas molecule by heating, effectively utilizes gas molecules generated to break through the Van der Waals force between graphite layers, uses sealed cycle heat treatment to penetrate deeper the ammonium chloride intercalation agent and make the graphite sheet more spaced apart, effectively strips graphite, and has low cost. The graphene has complete structure, lesser defects, low oxygen content, and high yield and quality. DETAILED DESCRIPTION - Preparation of graphene comprises: (A) mixing graphite powder and ammonium chloride at mass ratio of 1:20-1:40, adding to ball mill tank, adding grinding balls of different sizes at ratio of 1-10:1 while controlling total added amount to 1/3-2/3 of the volume of ball mill tank, and ball milling at speed of 80-100 revolutions/minute for 2-4 hours to obtain graphite mixture; (B) adding to sealed vacuum reactor, vacuumizing to 40-60 degrees C for 3-6 hours, increasing temperature to 100-150 degrees C for 10-20 minutes, spray cooling to 20-40 degrees C for 0.5-2 hours, heating to 80-150 degrees C, heat preserving at 20-40 degrees C, and repeating cycle for 5-10 times; (C) heating to 100-150 degrees C, injecting ultrasonic auxiliary agent at 2/3-4/5 of the inner volume of reactor, opening vent hole on top of reactor, venting gas, releasing vacuum, returning pressure to normal pressure, injecting condensed water, cooling reactor to 50-60 degrees C, turning on ultrasonic generator, and ultrasonically stripping graphene-containing suspension; and (D) pumping, centrifugally concentrating to obtain high graphene content aqueous paste, or filtering to remove aqueous solution, or directly centrifuging, water washing or freeze-drying.