Abstract This chapter presents a clear survey of graphene preparation methods. The three main routes of mechanical exfoliation, oxidation-reduction, and intercalation-exfoliation are used in the top-down method. Although the mechanical exfoliation method is easier, graphene nanolayers prepared from the intercalation-exfoliation method provide high purity and yield. Against the high hydrophobicity of graphene, graphene oxide produced from oxidation-reduction methods possesses hydrophilic functional oxidized groups. Although pyrolysis and vapor deposition are reported for the bottom-up method, less progress has been reported. The application of graphene as a component material of supercapacitors, a type of energy storage device, attracts great attention. Graphene provides high power density and stability in electric double layer capacitors, but hybridization with pseudecapacitor materials is required for supplying efficient energy density.