Method for preparing multi-layer graphene

The invention relates to a method for preparing multi-layer graphene, and belongs to the technical field of carbon materials. The multi-layer graphene is prepared from expanded graphite serving as a raw material through ultrasonic dispersion, solid-liquid separation and drying. The thickness of the multi-layer graphene prepared by the method is between 1 and 10nm; the number of layers is between 2 and 20 layers; and the aperture is mainly between 6 and 50nm. The multi-layer graphene has the characteristics of high electrical conductivity, high heat conductivity, high electromagnetic wave absorptivity, wear resistance and the like. The method has the advantages of simpleness, convenient operation and low production cost, capability of reducing production energy consumption, no three wastes emission, environmental friendliness and convenient popularization and application. The multi-layer graphene prepared by the method can be used as the electrode materials of batteries and super capacitors, can also be used as the conductive agents of high molecular materials, ceramic materials, silicate materials and the like, and can also be used as the conductive agents of lithium batteries, alkaline batteries and nickel-metal hydride batteries.