▎ 摘　　要

NOVELTY - The preparation of graphene involves carrying out oxidation of graphite using natural flake graphite and oxidizing agent, washing, drying, carrying out oxidation again by using oxidized raw materials, re-dispersing in concentrated sulfuric acid, adding potassium permanganate and oxidizing agent, adding hydrogen peroxide, (2) washing oxidized product with dilute hydrochloric acid to remove metal ions and sulfate ions, cleaning, re-dispersing to obtain suspension, (3) carrying out solid-liquid separation, separately collecting graphite oxide and solvent, (4) wet-washing and drying. USE - Preparation of graphene used as electrode material of supercapacitor, and conductive agent of nickel metal hydride (NiMH) battery, multi-layer graphene battery, lithium-ion battery and alkaline battery. ADVANTAGE - The graphene is prepared by simple process at low cost without carrying out high-temperature treatment and without using catalyst and strong reducing agent, with low energy consumption, recycles the solvent of the production process, and is environmentally-friendly. DETAILED DESCRIPTION - The preparation method of graphene involves (1) carrying out oxidation of graphite twice, carrying out oxidation using natural flake graphite as raw material, and using oxidizing agent for pre-oxidation for 4 to 8 hours, washing with deionized water until neutral, drying at room temperature, carrying out oxidation again by using oxidized raw materials, re-dispersing in concentrated sulfuric acid, adding potassium permanganate and oxidizing agent as raw material for 2 hours, adding deionized water, diluting at 50 degrees C, adding 30% hydrogen peroxide, (2) washing the oxidized product with dilute hydrochloric acid to remove the remaining metal ions and sulfate ions in the product, cleaning using low boiling point polar organic solvent to neutral, re-dispersing in very low boiling point organic solvent to obtain suspension, (3) carrying out solid-liquid separation of the obtained suspension by centrifugal separation, subjecting the mixed solution to solid-liquid separation, separately collecting graphite oxide and solvent, (4) wet-washing graphite oxide using organic solvent to neutral, and drying at 80-150 degrees C for 60-300 minutes. The oxidizing agent for pre-oxidation is concentrated sulfuric acid, phosphorus pentoxide and ammonium persulfate. Low-boiling polar organic solvent comprises acetone, methanol and ethanol.