Hierarchical Porous Graphene/Ni Foam Composite with High Performances in Energy Storage Prepared by Flame Reduction of Graphene Oxide

A highly conducting porous architecture with plenty of stable oxygen-containing groups is designed to endow graphene electrodes with both high rate performance and high capacitance in energy storage. By exposing the graphene oxide/Ni foam composite to an epitaxial flame of a lighter for a few seconds, the resultant reduced graphene oxide/Ni foam (RGO/ Ni foam) composite shows a three-dimensional hierarchical porous structure with plenty of stable oxygen-containing groups, owing to the expansion and moderate reduction of graphene oxide sheets inside the Ni foam. As a supercapacitor electrode, the porous RGO/Ni foam composite exhibits an exceptional specific capacitance of 407.2 Fg(-1) at 500 mAg (-1). An enlarged operation voltage of 1.8 V is also realized when packaging the RGO/Ni foam composite into a symmetric twoelectrode cell configuration, exhibiting high energy density and power density. As an anode electrode in a lithium-ion battery, the first discharge/charge capacities of the RGO/Ni foam composite are 2194/1372 mAhg (-1) at 100 mAg (-1). This work gives great inspiration for the large-scale production of high-performance graphene- based electrodes for energy storage.