Effects of the composition of reduced graphene oxide/carbon nanofiber nanocomposite on charge storage behaviors

Porous carbon materials with hierarchical features are the important materials to study the electrochemical properties for supercapacitor electrode application. Depending on the synthesis procedures and the carbon precursors used, these carbon materials possess different structures, and they are always associated with different amounts of various oxygen functional groups affecting the wettability, conductivity, and electrochemical performance. In this context, various electrochemical methods are adopted to study the charge storage contribution. Among them, separation of surface-controlled (capacitive) and diffusion-controlled currents from cyclic voltammetry (CV) curve by using the potential sweep method (PSM) is a preferred method. Herein, three-dimensional "Reduced Graphene Oxide-Carbon Nanofiber" (rGO-CNF) hybrid materials are fabricated by using different rGO:CNF ratios to study the effect of the composition of rGO and CNF in the charge storage behaviors. The structural, elemental, and electrochemical characterizations of the materials are performed to quantitatively study the surface-controlled (capacitive) and diffusion-controlled charge storage contributions in the rGO-CNF hybrid. It is found that the increase of rGO content in the hybrid material significantly affects the electrochemical properties of the hybrid materials.