Rational construction of 3D NiCo2O4@CoMoO4 core/shell nanoarrays as a positive electrode for asymmetric supercapacitor

Abstract

Optimized nanostructures design for composite continuously improved the electrochemical performances of supercapacitors in the past few years. Herein, we have successfully fabricated NiCo2O4 Nanosheets@CoMoO4nanoflakes Core/shell Arrays on Ni foam by two steps of hydrothermal processing. The proposed nanoarchitectural design of active materials provides large interfacial area, abundant active sites for the electrolytic ions with the electrode materials and fast electron transport, which significantly improve the capacitive performance of individual electrodes and hence of the fabricated asymmetric supercapacitor. This electrode exhibits high specific capacitance of 1543.14 F g−1 (corresponding to area specific capacitance of 5.4 F cm−2) at a current density of 5 mA cm−2, good rate capability, and superior cycling stability with ∼95% capacitance retention after 1000 cycles. Asymmetric supercapacitor (NiCo2O4@CoMoO4//AC/graphene) with a maximum voltage of 1.6 V has demonstrated a high energy density of 42.75Wh·kg−1, a high power density of 11427 W·kg−1 at 29.52 Wh·kg−1, and out standing cyclic stability with the capacitance retention of 104% after 10000 cycles.