CN foam loaded with few-layer graphene nanosheets for high-performance supercapacitor electrodes

Abstract

Recently, three-dimensional porous carbon-based foams have attracted increasing interest owing to their exciting potential applications in various fields. Herein, hierarchical porous monoliths, CN foam loaded with free few-layer graphene nanosheets, have been prepared. In this method, graphene oxide sheets were first loaded on the usual melamine foam that was selected as the raw material for the CN framework. With a subsequent annealing process in N₂ atmosphere, the melamine foam was converted into a CN foam; simultaneously, the graphene oxide sheets were converted into reduced graphene oxide, to form a reduced graphene oxide–CN composite. The loading density of graphene on the CN framework can be tuned by the dosage of graphene oxide. The obtained composite monoliths exhibit excellent cycling performance and good rate capacity when used as pseudocapacitive electrode materials. At current densities of 0.5 and 10 A g⁻¹, the optimized electrode exhibits areal specific capacitance of 1067 and 463 mF cm⁻², respectively, with excellent cycling stability. The excellent property can be attributed to the unique macropore structures that endow sufficient space available to interact with the electrolytes, and the pseudocapacitive contribution originated from the nitrogen and oxygen composition. This facile synthesis strategy and the good electrochemical properties suggest that the synthesized CN–graphene composites are promising materials for supercapacitor application.