Hierarchical\nNanohybrids with Porous CNT-Networks\nDecorated Crumpled Graphene Balls for Supercapacitors

Abstract

One of the most challenging\nissues in developing supercapacitor\ntechnology is the rational design and synthesis of active electrode\nmaterials, at the nanoscale, with favorable morphologies, reasonable\nporous structure, and excellent conductivity. By transforming a two-dimensional\n(2D) graphene sheet into a crumpled ball shape, a novel three-dimensional\n(3D) graphene structure with a large surface area and aggregation-resistant\nproperties has been proposed as an active material in supercapacitors\nto address the issues associated with the restacking of 2D graphene\nsheets. To further improve the mass transport/electron transfer and\naddress the issue of limited contact spots between the crumpled graphene\nballs (CGBs) or between the CGBs and the current collector, we report\nhere a unique hierarchical nanohybrid with porous carbon nanotube\n(CNT)-networks decorated CGBs (p-CNTn/CGBs), which not only greatly\nimproves the affinity for bridging the active material and the current\ncollector but also maintains favorable features for supercapacitor\napplications, such as a large surface area, 3D hierarchical nanostructure,\nexcellent electrical conductivity, and outstanding aggregation-resistance.\nThe performance established on the p-CNTn/CGBs far exceeded the bare\nCGB and reduced graphene oxide (RGO) counterparts in terms of specific\ncapacitance and rate capabilities.