▎ 摘　　要

NOVELTY - Preparing graphene comprises e.g. (i) subjecting graphite to contact with intercalating agent first, washing and drying resulting mixture, (ii) subjecting product obtained in step (i) to first treatment under microwave irradiation to obtain first expanded graphite, (iii) subjecting first expanded graphite to second contact with intercalation agent, washing and drying resulting mixture, (iv) subjecting product obtained in step (iii) to second treatment to obtain second expanded graphite, and (v) subjecting second expanded graphite to sonication in aqueous solution of N,N-dimethylformamide. USE - The method is useful for preparing graphene (claimed). ADVANTAGE - The method has low cost, high yield, easy operation, high efficiency and excellent quality of graphene. DETAILED DESCRIPTION - Preparing graphene comprises (i) subjecting graphite to contact with intercalating agent first, and sequentially washing and drying resulting mixture, (ii) subjecting product obtained in step (i) to first treatment under microwave irradiation to obtain first expanded graphite, (iii) subjecting first expanded graphite to second contact with intercalation agent and sequentially washing and drying resulting mixture, (iv) subjecting product obtained in step (iii) to second treatment under microwave irradiation to obtain second expanded graphite, and (v) subjecting second expanded graphite to sonication in aqueous solution of N,N-dimethylformamide.