Synthesis of edge-rich vertical multilayer graphene nanotube arrays towards high-performance supercapacitors

In this work, we demonstrate the synthesis of edge-rich vertical multilayer graphene nanotube arrays and edge density-dependent capacitance in a supercapacitor application. We employ Ni-Au multi-block vertical nanotubes fabricated by anodic aluminum oxide template-assisted electrodeposition as a designer substrate for multilayer graphene growth. This edge generation of graphene relies on the distinct carbon solubility of Au and Ni under chemical vapor deposition. Therefore the graphene edge density is tailorable by controlling the total number of bimetallic interfaces of alternating electrodeposited Ni and Au blocks. In supercapacitor applications, we found that the capacitance heavily correlates to the graphene edge densities. Multilayer graphene nanotubes with 18 bimetallic interfaces exhibit 8.4 times higher capacitance than those without interfaces. This experimental evaluation shows great promise to significantly enhance the supercapacitor capacitance by creating high-density edges on multilayer graphene.