The synthesis of graphene oxide nanostructures for supercapacitors: a simple route

In this work, we report a simple strategy for synthesis of graphene oxide nanostructures with various morphologies including single-, few-layer, and three-dimensional networks. Morphology control is achieved by adding different amounts of Ni²⁺ into a one-step hydrothermal process. The involved growth mechanisms for the morphology control are discussed. A random arrangement of graphene oxide nanosheets is suggested to induce the networks’ formation. Ni²⁺ facilitates the formation of graphene oxide’s preferential face-to-face overlapping structure, and high Ni²⁺ concentrations render adjacent graphene oxide sheets to combine each other tightly to form closely packed, layered structures. Compared with single-, few-layer graphene oxide, the electrode prepared by three-dimensional networks has a mass specific capacitance of 352 F g⁻¹ at v = 5 mV s⁻¹, which is much higher than that of recently reported three-dimensional graphene oxide nanostructures (240 F g⁻¹).