MnCo2S4 nanoflowers directly grown over nickel foam as cathode for high-performance asymmetric hybrid supercapacitors

Abstract

This work reports MnCo2S4 nanoflowers directly grown over nickel foam (NF) via a facile hydrothermal process for high-performance supercapacitors. The as-grown MnCo2S4 nanoflower electrode delivers a high specific capacitance of 1980 F g−1 and 1243 F g−1 at 1 A g−1 in three-electrode and symmetric two-electrode configurations respectively. It also gives a cyclic performance of 97 % and a coulombic efficiency of 98 % at 5 A g−1 after 10,000 charge-discharge cycles. Furthermore, an asymmetric supercapacitor (ASC) device is fabricated using MnCo2S4 nanoflower cathode and rGO -based anode. The asymmetric supercapacitor exhibits superior performance with an increased gravimetric capacitance of 162 F g−1 at 1 A g−1, an excellent cycle life of 99 % along with a high coulombic efficiency of 99.5 % after 10,000 cycles. The device delivers a gravimetric energy density of 73 W h kg −1 at a gravimetric power density of 151 W kg −1. The present study demonstrates the potential of MnCo2S4 nanoflower-based electrodes for supercapacitor applications.