Research progress in preparation of graphene by mechanical exfoliation

The preparation methods of graphene as a "star" material were mainly tended to chemical ways in recent years. However, many intrinsic physical properties of graphene were discovered from the graphene that was prepared by micro-mechanical peeling method. In this review, the recent advances in all kinds of mechanical exfoliation methods which contained "scotch tape" method, "nanopencil" method, ultrathin sections method, ultrasonic method, planetary ball milling method, stirred ball milling method, low energy pure shear milling method and three-roll milling method were highlighted, and the advantages and disadvantages of these methods were analyzed. The development trend of mechanical exfoliation was prospected.