Ultrathin porous hierarchically textured NiCo2O4–graphene oxide flexible nanosheets for high-performance supercapacitors

Abstract

The ultimate goal of supercapacitor research industries is to develop devices which could be used as flexible, portable, ultrathin and highly-efficient power sources. However, the bulk NiCo₂O₄ materials prevent the achievement of high energy density as well as immense rate performance due to the limited electroactive surface area. In this work, we proposed a new breakthrough strategy to develop highly porous hierarchical flexible nanosheets of NiCo₂O₄–graphene oxide (NiCo₂O₄–GO) on nickel foam by a facile electrochemical deposition method. The morphogenesis of the NiCo₂O₄–GO hybrid nanostructure-based electrode exhibits hierarchical porous flexible nanosheet-like structures. The electrochemical properties of these electrodes were investigated by cyclic voltammetry and galvanostatic charge–discharge measurements in 3 M KOH electrolyte. The obtained results exhibit that this new hybrid nanostructure has a specific capacitance of 1078 F g⁻¹ at a discharge current of 1 mA with great cyclic stability. These excellent capacitive performances of NiCo₂O₄–GO can be attributed to its hierarchical porous nanosheet-like unique structure. This unique structure provides efficient ion transport that is highly desirable for superior rate capability and excellent cycling stability. Hence, our method provides a promising facile and binder-free nanostructure electrode for next generation high-performance supercapacitor applications.