NiO@NiO and NiO@Co³O⁴ Hollow Core/Shell Composites for High-Performance Supercapacitor Electrodes.

Abstract

In the present work, NiO@NiO and NiO@Co³O⁴ core/shell composites have been fabricated by a facile hydrothermal process and investigated as electrodes for supercapacitors. The structure and the morphology of as-prepared samples 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 NiO nanosheets and Co³O⁴ nanowires. Electrochemical properties were evaluated by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. According to the results NiO@NiO and NiO@Co³O⁴ core/shell composites exhibited high specific capacitance, being promising for high-performance supercapacitors.