▎ 摘　　要

NOVELTY - Preparing graphene comprises e.g. carbonizing intermediate phase carbon microsphere under nitrogen protection, carbonizing the intermediate phase carbon microsphere under argon gas atmosphere then raising temperature to 2300-3000 degrees C, keeping the temperature for 1-5 hours, carrying out graphitization process, to obtain graphitized intermediate phase carbon microsphere, taking carbon microsphere, adding mixed acid, adding potassium permanganate for pre-oxidation, stirring, raising temperature to obtain solution, filtering, adding deionized water. USE - The method is useful for preparing graphene (claimed), which is used in energy sources e.g. lithium battery, and solar energy battery. ADVANTAGE - The method can easily control layer number, is simple, produces graphene with less than five layers. The graphene has purity of more than 90%, has high quality and yield. DETAILED DESCRIPTION - Preparing graphene comprises (i) carbonizing intermediate phase carbon microsphere under nitrogen protection, carbonizing the intermediate phase carbon microsphere under argon gas atmosphere then raising temperature to 2300-3000 degrees C, keeping the temperature for 1-5 hours, carrying out graphitization process, to obtain graphitized intermediate phase carbon microsphere, (ii) taking the graphitization intermediate phase carbon microsphere, using mixed acid, adding potassium permanganate for pre-oxidation, at room temperature stirring for 0.5-3 hours, raising temperature to 40-70 degrees C, to obtain solution, filtering and stirring for 0.5-3 hours, adding deionized water, using hydrogen peroxide and potassium permanganate termination reaction, obtaining oxidized graphite and hydrochloric acid solution and deionized water for washing the 4-8 wt.% precipitate, again adding deionized water and ultrasonic dispersing precipitate for 2-5 hours to obtain oxidized graphene aqueous solution, (iii) centrifugal separating oxidized graphene alkene solution, taking upper layer oxidation graphene aqueous solution at 50-80 degrees C oven in drying box, obtaining oxidized graphene, and (iv) taking oxidation graphene in nitrogen or argon gas at 800-1200 degrees C high temperature keeping for 30-80 seconds heat reduction, sieving removing not by reduction and oxidation expanding graphite granule, graphite and alcohol mixture for carrying out ultrasonic dispersing, room temperature drying, drying again 8-12 hours through 120-150 degrees C vacuum condition, to obtain controllable graphene layer.