Hierarchical porous NiCo2O4 nanograss arrays grown on Ni foam as electrode material for high-performance supercapacitors

A novel hierarchical porous NiCo2O4 nanograss array directly grown on Ni foam is successfully synthesized through a facile hydrothermal method combined with a thermal treatment. When used as the electrode material for supercapacitors, an areal capacitance of 2.1 F cm(-2) was obtained under a current density of 2 mA cm(-2). After 4000 charge-discharge cycles, a high areal capacitance retention of 88% could be achieved. The outstanding electrochemical performance was attributed to the novel structure of the hierarchical porous NiCo2O4 nanograss arrays and the Ni foam used as the current collector. The novel hierarchical porous NiCo(2)O4 nanograss arrays are a promising electrode material for supercapacitors.