Effects of chemical composition and vacant oxygen defects on the performance of Ni(OH)2–Ni0.85Se heterostructure nanowires as supercapacitor electrodes

Abstract

The research focus of supercapacitors is the composition and structural design of electrode materials. Therefore, it will be a new challenge to prepare controllable electrode materials for constructing surface defects and porous structures. An electrode material of porous Ni(OH)₂–Ni_0.85Se heterostructure nanowires grown on NF is prepared by a hydrothermal reaction method, which has a large surface area and abundant active sites. Through experimental characterization and electrochemical analysis, its unique porous structure for ion transport provides abundant channels, and the surface rich in defects provides abundant and effective active sites for ion entry/exit and reaction. With an increase in Ni_0.85Se composition, the specific surface area of the heterostructure nanowire electrode material increases and the heterostructure composition also affects the electrochemical property of a supercapacitor. A supercapacitor assembled with a porous NF/Ni(OH)₂–Ni_0.85Se heterostructure nanowire electrode has excellent specific capacitance (283.6 F g⁻¹ at 1 A g⁻¹) and cycling stability (83.6% after 2000 cycles at 1 A g⁻¹). This work provides a method for the controllable preparation of electrode materials with surface defects and pore structures.