Facile synthesis of porous nanostructures of NiCo2O4 grown on rGO sheet for high performance supercapacitors

Abstract Porous nanowires (NWs) and nanoflowers (NFs) type structures of nickel cobaltite (NiCo2O4) were synthesized on rGO sheet (rGO@NiCo2O4) as supercapacitor electrode material. The synthesized materials are characterized using different experimental techniques. The growth of NiCo2O4 over rGO sheet is confirmed by the appearance of D and G bands in the Raman spectrum. The rGO@NiCo2O4 NFs electrode revealed relatively high value of specific capacity (436 C/g at current density of 1 A/g) with good capacity retention compared to other electrodes. The improved electrochemical activity of the rGO@NiCo2O4 NFs electrode may be due to the porous nanostructure of NiCo2O4 on rGO sheet. The rGO sheets provide easy access to ions, large surface area and large active sites with stable structural integrity. The Nyquist plot of the rGO@NiCo2O4 NFs electrode shows relatively low values of Rs and Rct compared to other electrodes, which essentially refer to its improved electrical conductivity. Thus, the rGO@NiCo2O4 NFs may be used as a supercapacitor electrode material for device fabrication.