A layer-by-layer deposition strategy of fabricating NiO@rGO composites for advanced electrochemical capacitors

Although graphene oxide (GO) can be well dispersed in aqueous solution, direct reduction of GO in solution usually results in irreversibly precipitated agglomerates due to strong π-π interactions. Such a problem could be avoided by preparing layered graphene-based materials using an electrostatic spray deposition (ESD) technology. A composite film consisting of NiO nanograins@reduced graphene oxide nanosheets (NiO@rGO) with layered structure was realized by a facile one step binder-free ESD approach. It was deposited directly onto the nickel foam and showed excellent electrochemical capacitor properties, about 881 F g−1 at a current density of 0.5 A g−1 and 667 F g−1 at 50 A g−1 with an excellent cycling ability. Furthermore, this technique opens a new access to the preparation of layered graphene based composites with novel structures and properties.