A simple process to prepare nitrogen-modified few-layer graphene for a supercapacitor electrode

We report a simple approach to prepare the nitrogen-modified few-layer graphene (FLG) directly from graphite flakes. With the aid of melamine, graphite flakes can be directly ultrasonicated into FLG in acetone. The subsequent annealing process further transforms the melamine absorbed on the surface of graphene into melon (C₆N₉H₃)_x, which is one type of condensation product of melamine, and simultaneously dopes the graphene with nitrogen. When tested as a supercapacitor electrode, the nitrogen-modified FLG shows a much higher specific capacitance (e.g., 227 F/g at 1A/g) than that of reduced graphene oxide (rGO) (e.g., 133 F/g at 1A/g).