LAUSR

Hybridising 2D materials into 3D aerogels have attracted considerable interest in ultralight electrochemical energy storage devices. However, to optimise the device structure for more efficient charge storage and transport, a better understanding of the ratio-dependent hybridisation process and interface charge transfer mechanisms are highly required. Here, we perform a comprehensive study to elucidate the fundamental process during the reduced graphene oxide (rGO) and carbon nanotube (CNT) hybridisation, which enabled the fabrication of a rational-designed rGO/CNT hybrid aerogel (GCA) with a record energy storage performance beyond previously reported works. Based on spectroscopy and microscopy analysis, we found the hydrophilic and hydrophobic transition of GO which eliminates the surface-functionalised oxygen-containing moieties, is the origin of the π-π stacking hybridisation between rGO and CNTs. Moreover, we found the different amount of CNTs ‘solder’ in-between rGO sheets can offer GCA distinct mechanical elasticity, ion diffusion resistance and specific capacitance. As illustrated in the electrochemical impedance spectroscopy (EIS) and charge/discharge analysis, we found GCA 2-2 (rGO:CNT=2:2) display the best gravimetric capacitance of 117 F∙g-1 at a discharge current density of 1 A∙g-1, which help us to fabricate an ultra-flyweight supercapacitor with a large energy density of 3.53 Wh∙kg-1 at a power density of 283.4 W∙kg-1.