Synthesis of interconnected hierarchically porous carbon networks with excellent diffusion ability based on NaNO3 crystal-assisted strategy for high performance supercapacitors

Hierarchically porous carbon materials obtain extensive research interest as promising electrode for supercapacitors. However, the straightforward synthesis approach of hierarchically porous carbon materials with rational structure to satisfy supercapacitor applications is still a great challenge. In this work, a novel interconnected hierarchically porous carbon network with large specific surface (1864 m(2) g(-1)), high pore volume (2.22 cm(3) g(-1)) and nitrogen doping is prepared from a facile and emerging NaNO3 crystal-assisted synthesis strategy. These unique structural features guarantee the enhanced charge transfer, high ion adsorption and buffering, which result in a high utilization efficiency of specific surface area. In 6.0 M KOH aqueous electrolyte, the optimized carbon sample exhibits a specific capacitance of 385 F g(-1) at 1 A g(-1) and still reaches 291 F g(-1) at 100 A g(-1). Symmetric supercapacitors based on the hierarchically porous carbon network can deliver 11.6 Wh kg(-1) and 96.3 Wh kg(-1) outputs in KOH and EMIMBF4 electrolytes. The superior electrochemical performance is ascribed to an integrated effect of highly developed interconnected hierarchically porous morphology, large specific surface area, as well as elemental O/N-doping. In addition, finite element simulations reveal that the unique hierarchically porous structure substantially promotes mass transport rate by shortening ion diffusion paths in the cavity of electrode material achieving an excellent diffusion ability. This work opens a new venue for promising scalable production of interconnected hierarchically porous carbon networks for future advanced energy applications.