Probing electrochemical charge storage of 3D porous hierarchical cobalt oxide decorated rGO in ultra-high-performance supercapacitor

Abstract A 3D porous hierarchical Co3O4-reduced graphene oxide nanosheet (Co3O4-rGO) heterostructure is synthesized by a facile hydrothermal method. Microstructure analysis confirms the decoration of Co3O4 hierarchical structures with an urchin-like spherical microstructure on rGO nanosheet with an average size of about 50 nm. The structural analysis reveals the formation of phase pure spinel Co3O4 and reduced graphene showing their simultaneous existence in the composite. Raman spectroscopy confirms the successful reduction of graphite oxide to reduced graphene oxide and the effectual interaction between Co3O4 and rGO matrix. The Co3O4-rGO composite electrode possesses utmost specific capacitance 688 F g−1, due to effective ion transfer and slight agglomeration of Co3O4 hierarchical structures on the surface of reduced graphene oxide. It is noteworthy that we have demonstrated a flexible solid-state supercapacitor device that exhibits an excellent performance suggesting the possible use of 3D porous hierarchical Co3O4-rGO composite in supercapacitor devices.