Full synergistic contribution of electrodeposited three-dimensional NiCo2O4@MnO2 nanosheet networks electrode for asymmetric supercapacitors

The performance of supercapacitors electrode materials depends on not only their structures but also selected electrolyte as well as proper potential window. The 3D hierarchical NiCo2O4@MnO2 hybrid nanomaterial was grown on stainless-steel mesh through a two-step electrodeposition process. The resultant interconnecting network consisting of porous nanosheets possesses open geometry and porous nature. When being employed in supercapacitor, the pseudocapacitive contributions (redox reaction on surface or near-surface) of two components are taken into account comprehensively in a wide potential window. This makes such a hybrid network deliver a high specific capacitance of 913.6 F/g at 0.5 A/g and 12.9% capacitance loss after 3000 cycles in KOH solution. Remarkably, an asymmetric supercapacitor based on NiCo2O4@MnO2 hybrid networks as the positive electrode and activated carbon (AC) as the negative electrode achieves an energy density of 37.5 Wh/kg and a maximum power density of 7500 W/kg. These attractive findings make this NiCo2O4@MnO2 hybrid networks hold promise in energy storage device as an efficient electrode.