An ultrafast supercapacitor built by Co3O4 with tertiary hierarchical architecture

The fast charge/discharge ability is very important for electric energy storage devices. Here, Co3O4 electrode with flower-wire-nanoparticle tertiary hierarchical architecture for ultrafast charge/discharge rate supercapacitor is developed via a facile and scalable hydrothermal method and subsequent sintering treatment. The as-prepared Co3O4 electrode exhibits an outstanding rate performance of 95.6% capability at 80 times current density from 0.5 A g−1 to 40 A g−1 and a good cycling stability of 98.5% retention after 2000 charge/discharge cycles at the current density of 2 A g−1. The Co3O4//AC asymmetric supercapacitor reveals an energy density of 16.25 Wh kg−1 at a power density of 7500 W kg−1. These impressive electrochemical behaviors suggest that such Co3O4 tertiary hierarchical architecture holds great promise for high-rate energy storage devices.