Facile synthesis of Ni(OH)2 nanoarrays on graphene@carbon fabric as dual-functional electrochemical materials for supercapacitors and capacitive desalination

Abstract

A high-performance Ni(OH)₂ nanoarray on graphene (RGO)@carbon fabric nanocomposites with hierarchical nanostructures were facilely synthesized, which involves (i) coating of graphene on a carbon fabric; and (ii) in situ growth of Ni(OH)₂ nanoarray on the graphene surface. It was found that Ni(OH)₂ nanoplates grew evenly on the surface of graphene without stacking. This unique structure of the electrode material favors a higher electrochemical active site, endowing the enhancing capacity performance. The morphology and microstructure of the as-prepared composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) techniques. Capacitive properties of the as-synthesized electrodes were studied via cyclic voltammetry, charge/discharge, and electrochemical impedance spectroscopy in a three-electrode experimental setup. Taking advantage of the unique structure of Ni(OH)₂/RGO@carbon fabric nanocomposites, this material as dual-functional electrodes shows decent performance for both supercapacitors and capacitive desalination (CDI). The specific capacitance was calculated to be 1325 F g⁻¹ at 1 A g⁻¹; moreover, this material shows a high rate capability, whereby the capacitance can be maintained at 612 F g⁻¹ even at 10 A g⁻¹. Besides, its performance as potential CDI electrodes was explored. Such high-performance Ni(OH)₂/RGO@carbon fabric hierarchical nanostructures can offer great promise in large-scale energy storage device applications.