Since the first preparation in 2004,graphene has attracted a great deal of interest in electrochemical energy systems because of its atom-thick 2D structure with fascinating physical and chemical properties.So far,oxidation-exfoliation-reduction method is the most widely used strategy for lab scale production of graphene due to the naturally abundant graphite precursor and relative ease of preparation.Moreover,the presence of defects and residual functional groups on the as-obtained graphene is generally beneficial for applications in electrochemical energy systems,such as Li-ion batteries(LIBs).