A spinel MnCo2O4/NG 2D/2D hybrid nanoarchitectures as advanced electrode material for high performance hybrid supercapacitors

Abstract

Supercapacitors suffer from lack of energy density and to achieve better energy density, a new class of hybrid architectures with controlled morphology is prerequisite. Here, a facile polyol method is successfully used for the synthesis of MnCo2O4/nitrogen doped graphene 2D/2D hybrid nanoarchitectures and this combination successfully avoids the restacking and agglomeration of nitrogen−doped graphene nanosheets. The formation of MnCo2O4/NG 2D/2D hybrid nanoarchitectures are confirmed by state−of−art techniques. This combination leads to a large conducting network that improves the exposure of active sites at the electrode−electrolyte interface for the transportation of electrons and ions. The synergistic effect of 2D MnCo2O4 nanoflakes over the 2D nitrogen−doped graphene serves the capacitance of ca. 1170 F g−1 at 1 A g−1 with an excellent rate capability of 818 F g−1 at 20 A g−1. An asymmetric supercapacitor is successfully fabricated using these MnCo2O4/NG 2D/2D hybrid nanoarchitectures as the cathode and 2D nitrogen−doped graphene as the anode electrodes, which exhibits better performance than previously reported spinel metal oxide materials. The asymmetric supercapacitor exhibits excellent energy density (∼48.5 Wh kg−1 at ∼808 W kg−1) and power density (∼16000 W kg−1 at ∼32.1 Wh kg−1), with an outstanding cyclic durability of 85.9% retention after 10,000 cycles.