▎ 摘　　要

NOVELTY - The method comprises: adding sulfuric acid solution and nitric acid solution in graphite and then stirring for 24 hours to obtain a graphite-acid mixture; adding an oxidizing agent in the mixture at below 20 degrees C; stirring the mixture for 72 hours; neutralizing the mixture by washing with distilled water; vacuum drying the mixture at 80 degrees C to generate a graphite oxide; and performing heat treatment on the graphite oxide at 700-2000 degrees C in an argon gas atmosphere for 5 minutes and then carrying out oxidation-reduction reaction to obtain a graphene sheet. USE - The method is useful for manufacturing a graphene sheet (claimed) that is useful for a display device such as plasma display panel, LED, LCD, cold-cathode fluorescent lamps and flat fluorescent lamp and electronic and electric devices. ADVANTAGE - The method allows economical manufacture of the ultra thin graphene sheet with high quality and thermal conductivity. DETAILED DESCRIPTION - The method comprises: adding sulfuric acid solution and nitric acid solution in graphite and then stirring for 24 hours to obtain a graphite-acid mixture; adding an oxidizing agent in the mixture at below 20 degrees C; stirring the mixture for 72 hours; neutralizing the mixture by washing with distilled water; vacuum drying the mixture at 80 degrees C to generate a graphite oxide; and performing heat treatment on the graphite oxide at 700-2000 degrees C in an argon gas atmosphere for 5 minutes and then carrying out oxidation-reduction reaction to obtain a graphene sheet. A mass ratio of the sulfuric acid solution and the nitric acid solution is 7:3. The graphene sheet has thermal conductivity of 700-2000 W/mk.