Core−shell NiSe/Ni(OH)₂ with NiSe nanorods and Ni(OH)₂ nanosheets as battery-type electrode for hybrid supercapacitors

Novel core−shell nanostructure electrodes benefit from the excellent properties of their constituent materials, as well as the synergy between them. However, it is challenging to fabricate such structures efficiently. In this study, NiSe nanorods were fabricated using Ni foam as the conductive substrate and reactant via a one-step hydrothermal process, and Ni(OH)₂ nanosheets were coated on the surface of the nanorods via one-step electrodeposition. The effect of the structure and morphology on the properties of the material was explored using scanning electron microscopy, x-ray diffraction, and electrochemical technology. The obtained core−shell NiSe/Ni(OH)₂ exhibited an areal capacity of 1.89 mAh cm⁻² at a current density of 5 mA cm⁻². The assembled NiSe/Ni(OH)₂//AC hybrid supercapacitor exhibited excellent energy and power densities, indicating that NiSe/Ni(OH)₂ has great potential for use as a battery-type electrode in energy storage systems. (paper)