▎ 摘　　要

NOVELTY - Preparing graphene comprises e.g. (i) adding sulfuric acid in the reaction kettle, stirring and cooling by the first stirring rod, (ii) adding potassium permanganate in the reaction kettle, stirring and cooling by the first stirring rod; (iii) heating by the heat released by the reaction; (iv) adding graphite, and controlling the reaction temperature; (v) centrifuge filtering to obtain primary graphene; (vi) sequentially adding hydrogen peroxide and clear water into centrifuge, and washing to obtain secondary graphene; (vii) shearing the secondary graphene into required size. USE - The method is useful for preparing graphene. ADVANTAGE - The method: can produce high-purity graphene; meets large-scale demand in field of energy storage materials and functional composite materials; and simple and environmentally-friendly. DETAILED DESCRIPTION - Preparing graphene comprises (i) adding sulfuric acid in the reaction kettle, stirring and cooling by the first stirring rod, where the temperature after cooling is 100C-150 degrees C, (ii) adding potassium permanganate in the reaction kettle, stirring and cooling by the first stirring rod, where the reaction temperature is less than 200 degrees C; (iii) heating by the heat released by the reaction, where the temperature after heating is 300-350 degrees C; (iv) adding graphite, and controlling the reaction temperature at 330-370 degrees C; (v) centrifuge filtering to obtain primary graphene; (vi) sequentially adding hydrogen peroxide and clear water into centrifuge, and washing to obtain secondary graphene; (vii) shearing the secondary graphene into required size through shearing machine (37) to obtain three-level graphene; (viii) performing ultrasonic treatment on three-level graphene to obtain four-stage graphene; (ix) vacuum extracting on four-stage graphene by using decompression distillation device to obtain four-order graphene; and (x) centrifuging. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the shearing machine.