Nanogold Spacing of Stacked Graphene Nanofibers for Supercapacitors

Graphene exhibits great potential for energy storage devices in electrochemical supercapacitors as it is a lightweight, inexpensive material. However, as graphene nanomaterials are prone to stacking and therefore blocking electroactive sites, its real capacity is low. Recently, there has been a significant interest in quasi 1D structures of carbon nanofibers with radially oriented graphene sheets, called stacked graphene nanofibers graphite nanofibers or nanoribbons. Such nanofibers exhibit an unparalleled amount of edge sites on their surface. In this study, we use gold nanoparticles as nanospacers for separating stacked graphene nanofibers. We investigate the dependence of the capacitance of stacked graphene nanofiber/nanogold nanocomposites upon the size of gold nanoparticles (2-150 nm) and the amount of gold nanospacers in the composite. It was found that properly sized gold nanoparticles (of 40 nm) used as nanospacers of both 45 nm and 90 nm diameter stacked graphene nanofibers can increase the capacitance of nanofibers by three times.