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

Abstract

AbstractA 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 F g−1 at 500 mA g−1. An enlarged operation voltage of 1.8 V is also realized when packaging the RGO/Ni foam composite into a symmetric two‐electrode 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 mA h g−1 at 100 mA g−1. This work gives great inspiration for the large‐scale production of high‐performance graphene‐based electrodes for energy storage.