Abstract
We report a facile method to produce composites of hierarchically porous graphene-based materials embedded with onion-like carbons (Gr-OLCs) for high power density supercapacitors. Gr-OLCs were produced from the mixture of glucose, thiourea, and ammonium chloride, through the condensation reaction and subsequent blow into three-dimensional (3D) structure, and carbonization process. Owing to its high surface area, hierarchical pore distribution, and interconnected carbon networks embedded with onion-like carbons, this carbon exhibited the specific capacitance of 140 F g-1 at a high current density of 64 A g-1. Highly porous and interconnected carbon structure tend to facilitate the movement of electrolyte ions within the electrode and provide an efficient pathway for the movement of charge carriers, resulting in an exceptionally high power density of 1,737 kW kg-1, while maintaining its high energy density of 30 Wh kg-1 at current density of 256 A g-1. Studies on the complex capacitance of the cell revealed that these carbon electrodes possess stable energy storage features with minimal capacitive loss, achieving both high power and energy densities. This work may provide a new type of carbon-based electrode materials which can meet the requirements for high power energy storage devices.
Biomass-Derived Graphene-Based Materials Embedded with Onion-Like Carbons for High Power Supercapacitors
