Bismuth oxide/nitrogen-doped carbon dots hollow and porous hierarchitectures for high-performance asymmetric supercapacitors

Abstract The development of high-performance anode materials is critical for next-generation asymmetric supercapacitor devices. Herein, an advanced anode of bismuth oxide/nitrogen-doped carbon dots (Bi2O3/NCDs) hollow and porous hierarchitecture was successfully developed by a facile two-step strategy. It is revealed that the presence of NCDs can not only induce the assembly of Bi2O3 porous nanosheets to hollow microspheres, but also remarkably improve the specific capacitances of them. Attributing to the intriguing properties of NCDs and the unique structure of Bi2O3/NCDs composites, the Bi2O3/NCDs hierarchitectures deliver an enhanced specific capacitance of approximately 1046 F g−1 at a current density of 1 A g−1. In particularly, an asymmetric supercapacitor was constructed by using the Bi2O3/NCDs hierarchical microspheres as anode and Ni(OH)2/NCDs nanosheets as cathode, which exhibits an ultrahigh energy density of about 79.9 Wh kg−1 at 770.9 W kg−1. These results indicate that the Bi2O3/NCDs hollow and porous hierarchitectures hold great potential as novel anode materials for energy storage.