Reduced graphene oxide/hierarchal spinel nickel cobaltite nanoflowers composites for supercapacitor electrodes with ultrahigh capacitive and excellent rate performance

Abstract

Researchers are extensively investigating transition metal oxides due to their unique porous architectural structure and remarkable electrochemical properties, which are suitable to boost the energy storage capabilities. In present work, facile chemical route was used to synthesize hierarchal spinel nickel cobaltite nanoflowers anchored reduced graphene oxide (NiCo2O4-rGO) as high performance electrode material. NiCo2O4 anchored rGO demonstrated specific capacitance of 2695 Fg-1 at 1 Ag-1, which is greater than pristine NiCo2O4 nanoflowers specific capacitance. NiCo2O4-rGO showed excellent stability and retention capability of 96% after 2500 cycles at 5 Ag-1. Furthermore, NiCo2O4–rGO exhibited maximum energy density of 93.57 WhKg−1 at power density of 250 WKg-1. We have achieved specific capacitance and retention capability which is higher than previously reported results. This enhancement is mainly attributed to the spinel structure of NiCo2O4 and its robust structural affinity with rGO. Moreover, rGO possesses extended surface area provided ample of active sites and exceptional synergetic effect which helped to enhance the induction and consequently transportation of e−/h+. More importantly due to its special morphological effects, in future NiCo2O4 anchored rGO nanoflowers may open new avenue in research but also used as an efficient electrode material for the construction of high performance supercapacitors.