Large-scale synthesis of high-quality graphene sheets by an improved alternating current arc-discharge method

Large-scale synthesis of high-quality graphene sheets is essential for their development from the laboratory to commercial applications. In this work, we report a large-scale production of high-quality graphene sheets through an improved alternating current (AC) arc-discharge method under N-2/H-2 mixed buffer gases, and we successfully obtained similar to 2.1 g of graphene sheets in a short arc-discharge period of less than 5 min. The as-prepared graphene sheets exhibit a low-defect structure with no more than 5 layers. Both N-2 and H-2 are thought to be essential to the synthesis of high-quality graphene sheets. Furthermore, the volume ratio of N-2 and H-2 can be a key factor on lowering the defects and reducing the layer numbers of graphene sheets based on the experimental observations. In addition, the as-prepared graphene sheets are applied as an anode material for lithium-ion batteries and show good electrochemical reversibility. In view of the simplicity of the arc-discharge apparatus, the use of environmental friendly and low-cost N-2/H-2 gases, and the outstanding properties of graphene, this AC-powered method may have a great potential on being scaled up to an industrial level.