Facile synthesis of NiO@Ni(OH)-α-MoO nanocomposite for enhanced solid-state symmetric supercapacitor application.

Electrochemical supercapacitor fabrication using heterogeneous nanocomposite is one of the most promising pathways for energy storage technology. Herein, heterostructure based nickel-molybdenum (NiO@Ni(OH)-α-MoO) nanocomposites have been successfully prepared on nickel foil via hydrothermal route for supercapacitor application. The mixed phases of cubic, hexagonal, and orthorhombic crystal structure for NiO, Ni(OH), and α-MoO, respectively were observed by X-ray diffraction. Heterostructures of nanosheet and nanosphere morphologies were confirmed by high resolution transmission electron microscopy. Impressively, the NiO@Ni(OH)-α-MoO composite working electrode exhibits a high specific capacitance of 445 Fg at current density of 1 Ag and shows outstanding rate capability (97.3% capacity retention after 3000 cycles at 10 Ag), compared to that of NiO@Ni(OH) nanoparticles. Notably, two-electrode symmetric supercapacitor of NiO@Ni(OH)-α-MoO working electrode shows a high specific capacitance of 172 Fg at 0.5 Ag, excellent rate capability and good cycling stability. Also, an excellent cycling stability (capacity retention of 98% after 5000 cycles) is observed for NiO@Ni(OH)-α-MoO as a working electrode in the symmetric two-electrode system. The obtained attractive results demonstrate that nanocomposite anode material can be used for development of a wide-range of energy storage devices.