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.