Graphite is highly conductive layered materials that can be used for electrochemical intercalation/exfoliation to prepare graphene.Here we will show how the layer numbers, sheet sizes and defects of graphene be controllably synthesized.Especially, large literal sheets of single layer graphene flakes were produced at large scale.They can be used to fabricate robust, flexible and free-standing graphene films with high thermal conductivity of >3000 W/m· K.Through using graphene ink, conductive graphene coatings onto various substrates such as metal, glass and polymer can be readily prepared.The graphene flakes can also survive strong basic conditions at high temperature and decrease 200℃ of cellulose activation to fabricate hierarchical porous graphene/activated carbon hybrids.The new porous carbon material reached high supercapacities of 300 Fig in aqueous solution and of 210 Fig (3.5V) in ionic liquid and high energy density of 65 Wh/kg at high discharge rate of 6 Ag (Fig.1d-e).Further, small graphene microsheets directly from natural microcrystalline graphite minerals can be applied for as the anode material for a Li-ion battery with high-rate reversible spedfic capacity.Graphene dots from electrochemical cutting of graphene flakes show good oxygen reduction reactivity.