Facile synthesis of Co₃O₄ nanowires grown on hollow NiO microspheres with superior electrochemical performance

Abstract The NiO/Co₃O₄ core/shell composites as a promising supercapacitor material have been fabricated by facile hydrothermal process. The structure and morphology of the NiO/Co₃O₄ core/shell composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicated that the NiO hollow spheres were decorated by Co₃O₄ nanowires, and the nanowires were composed of nanoparticles. Electrochemical properties were characterized by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. The results suggested that the NiO/Co₃O₄ core/shell composites had good electrochemical reversibility and displayed superior capacitive performance with large capacitance (510 F g^-1). Moreover, NiO/Co₃O₄ core/shell composites showed excellent cyclic performanceafter 1000 cycles.