A green and ultrafast approach to the synthesis of scalable graphene nanosheets with Zn powder for electrochemical energy storage

We developed a novel and ultrafast method to reduce graphene oxide (GO) with Zn powder in mild alkaline conditions under ultrasonication only for 10 min at room temperature. The as-prepared graphene nanosheets (GNs) are characterized by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and so on. Moreover, we proposed the reducing mechanism under which Zn powder and GO formed numerous Zn-GO primary batteries in the presence of ammonia solution, which can effectively remove a significant fraction of the oxygen-containing functional groups and yield a C/O ratio as high as 8.09 and 8.58 reduced by ultrasonication for 10 min and 60 min, respectively. A maximum specific capacitance of 116 F g(-1) in an aqueous KOH electrolyte solution has been obtained. This approach presents us with a possibility for an environmentally friendly, ultrafast, low-cost and large-scale production of GNs and great potentials in electrochemical energy storage applications of graphene-based materials.