Hierarchically constructed Nickel Cobalt Sulfide/ Ni Co-layered Double Hydroxide core-shell Nanoarrays grown in situ on Nickel foam for Supercapacitors

Abstract

Battery-type electrodes consisting of hierarchically constructed nickel cobalt sulfide (denoted as NCS) core were fabricated employing a hydrothermal method with electrodeposited nickel cobalt layered double hydroxide (denoted as NCOH) core-shell nanotube arrays (denoted as NTAs) grown in situ on Ni foam for use in supercapacitors. The X-ray diffraction analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to characterize the structures and morphologies of the electrode materials. The nickel cobalt sulfide nanotubes coated with nickel cobalt layered double hydroxide nanosheets by electrodeposition for 40 s showed the highest specific capacitance (2105 F g−1 at the current density of 2 A g−1) and excellent cycling stability (65.1% capacitance retention after 3000 cycles). Moreover, a battery-type device based on NCS@NCOH as the positive electrode and carbon nanotube (denoted as CNT) as the negative electrode, delivering a specific capacity of 29.89 F g-1 at 0.5 A g-1, was fabricated for practical applications. The results show that the composite electrode material prepared by electrodeposition has great potential for application in energy storage devices.