Graphene nanowires anchored to 3D graphene foam via self-assembly for high performance Li and Na ion storage

Graphene has been extensively investigated as anode material for Li and Na ion batteries due to its excellent physical and chemical performance. Herein, we report a new member of ‘graphene family’, a reduced graphene nanowire on three-dimensional graphene foam (3DGNW). The novel graphene nanowires were synthesized via a template strategy involving reduction and assembly process of nanosized graphene oxides (nGO), pyrolysis of polystyrene spheres (PS) template and catalytic reaction between GO and PS decomposition products. When evaluated as anodes material for Li and Na ion batteries, the 3DGNW exhibits relatively low discharge-voltage plateau, excellent reversible capacity, rate capability, and durable tolerance. For anode of Na ion batteries, a reversible capacity of more than 301 mAh g⁻¹ without capacity fading after 1000 cycles at rate of 1 C were achieved. Even at rate of 20 C, a high reversible capacity of 200 mAh g⁻¹ can be retained. The superior electrochemical performance is ascribed to hierarchical multidimensional graphene architecture, high graphene crystallinity, expansile graphene interlayer distance, and extensively lateral exposed edges/pores, which can promote the electron and ion transport. The realization of assembling reduced graphene sheets to graphene nanowire offers new opportunities for energy storage application of graphene based assembly in future.