Facile growth of nickel foam-supported MnCo2O4.5 porous nanowires as binder-free electrodes for high-performance hybrid supercapacitors

Abstract

In this work, porous MnCo2O4.5 nanowires (NWs) were directly grown on nickel foam (NF) via an initial hydrothermal route with an extra annealing treatment of precursor. Another comparative experiment was conducted with a lower amount of urea to obtain particle-based MnCo2O4.5 films. These binder-free MnCo2O4.5@NF electrodes exhibited battery-type electro-chemical response with superior electro-chemical performance. Especially, the MnCo2O4.5-NWs@NF delivered a huge capacity of 288.47 C g−1 at 1 A g−1 and 78.07% of capacity retention at 10 A g−1. Moreover, a hybrid supercapacitor (HSC) that was assembled using activated carbon (AC) as an anode could operate over a voltage of 1.7 V. The MnCo2O4.5-NWs@NF//AC HSC delivered an energy density of up to 29.57 W h kg−1 at the power density of 914.28 W kg−1, and it could still hold 20.82 W h kg−1 since the power density was improved to 8.24 kW kg−1. In addition, both these MnCo2O4.5 NWs- and films-based HSCs showed an impressive cyclic stability over continuous 6000 cycles at a high current density of 6 A g−1, but only a little capacity decay was observed. Such extraordinary electro-chemical performance makes the binder-free MnCo2O4.5-NWs@NF electrode material promising and very feasible to be applied for electro-chemical energy storage devices such as batteries, supercapacitors, and so on.