Hierarchical multi-villous nickel-cobalt oxide nanocyclobenzene arrays: morphology control and electrochemical supercapacitive behaviors

Binary metal oxides have been regarded as ideal potential anode materials which display electrochemical performances which surpass those of single metal oxides, in terms of reversible capacity, structural stability and electronic conductivity. In this work, hierarchical multi-villous NiCo2O4 nanocyclobenzene arrays (NCAs) on nickel foam have been fabricated by a simple hydrothermal approach combined with a post-annealing treatment. Such unique nanoarchitectures exhibit a remarkable electrochemical performance, with high capacitance and a desirable cycle lifespan at high rates. When evaluated as an electrode material for supercapacitors, the NCAs supported on nickel foam are able to deliver a high specific capacitance of 1545 F g(-1) at a current density of 5 A g(-1) in 2 M KOH aqueous solution. In addition, the composite electrode shows excellent mechanical behavior and long-term cyclic stability (93.7% capacitance retention after 5000 cycles). All in all, the fabrication strategy presented herein is simple, cost-effective and scalable, which opens new avenues for the large scale application of these novel materials in energy storage.