Hierarchical grass like NiCo2O4 Nanoflakes on 3-dimensional microporous electrically conductive network with superior electrochemical performance

Abstract

Bimetallic oxide nickel cobaltite (NiCo2O4) nanoflakes are fabricated on the surface and sidewall of three dimensional microporous electrically conductive network (MECN) as the active electrode materials for miniature supercapacitors by hydrothermal method. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterisation of as-prepared material demonstrates that the nanostructure grown on the MECN consists of a NiCo2O4 nanoflake layer. Compared with the nanostructured nickel growth on the MECN, the as-prepared NiCo2O4/MECN nanoflake has shown enhanced electrochemical properties, manifesting a high capacitance of 607.29 F g-1 (7.29 F cm-2) at 10 mA cm-2 and good cycling stability of 60.60% capacity retention after 2000 cycles. Even at the power density of 1000.0 W Kg-1, the device still has the energy density of 134.71 Wh Kg-1 which is comparable to related research. The large specific capacitance and remarkable rate capability can attribute to the unique 3D ordered porous architecture, which facilitates electron and ion transport, enlarges the liquid-solid interfacial area, and enhances the utilization efficiency of the active materials. Meanwhile, the weight and size of the device are reduced.