Application of flammulina-velutipes-like CeO2/Co3O4/rGO in high-performance asymmetric supercapacitors

Abstract

In this study, a novel electrode of flammulina-velutipes-like CeO2/Co3O4/rGO nanoparticles on nickel foam substrate (CCGN) was prepared by hydrothermal synthesis and annealing. Hundreds of CeO2/Co3O4/rGO nanoparticles, which are similar in shape to the flammulina velutipes, form a cluster, and thousands of the clusters grow evenly on the surface of nickel foam substrate. All clusters are kept at similar distances and this arrangement and distribution provides ample expansion/contraction space for active substances during charging/discharging. The specific capacity of CCGN electrode reached 1606.6 F g−1 (964.0 C g−1) at the current density of 1 A g−1. In particular, CCGN//activated carbon (AC) asymmetric supercapacitors showed excellent power density and energy density (8000 W kg−1 at 47.6 Wh kg−1) when the voltage window was 1.6 V. And under the condition of 10 A g−1 current density, the capacitance retention rate is still extremely high 96.4% after 10,000 continuous charge and discharge tests. These remarkable features demonstrate the potential of CCGN electrodes for use in supercapacitors.