The preparation and electrochemical characterization of urchin-like NiCo2O4 nanostructures

The urchin-like NiCo2O4 nanostructures were synthesized by a mild hydrothermal method. A possible growth mechanism is proposed based on the morphology evolution process upon reaction time. The effect of the concentration of metal salt on the electrochemical performance was investigated. The high electrochemical performance was achieved by optimizing the concentration. The corresponding specific capacitance is as high as 1484.1 F g−1 at the current density of 1 A g−1. Furthermore, the capacitance retains 90.1% even after more than 2000 cycles. The resulting high performance is due to the unique three-dimensional structure constructed by nanorings and nanowires, which increases the amount of electroactive sites and facilitates the electrolyte penetration and electron transfer.