Graphene/LDHs Nanocomposites As Electrode Material For Supercapacitors

Graphene oxide (GO) as a template for morphology controllable synthesis of inorganic particles has recently attracted enormous attention. Since the discovery of graphene in2004, the preparation and application of graphene-based nanocomposites have attracted enormous research interest all over the world. Graphene is an ideal material for energy-storage applications owing to its unique two-dimensional geometry and excellent physical and chemical properties. The energy-storage field including batteries and supercapacitors will move forward continually as the development of the mass production of graphene materials. The inferior energy density over traditional batteries still limits the development of supercapacitors. Accordingly, graphene/LDHs based supercapacitors with high energy-storage capability attract tremendous interests. Hydrothermal method is considered as a promising and important one towards scalability among so many approaches of synthesis of graphene-LDHs attributed to its facility, efficiency and repeatability. In this study, we are going to produce graphene (LDHs) nanowires by using GO and adjusting the loading of urea in hydrothermal reactions. A series of graphene-LDHs based nanomaterials are prepared by the simple hydrothermal method. Furthermore, the morphology, component, structure of these nanocomposites are characterized by various analytical tools, such as SEM(?)TEM(?)XRD(?)XPS(?)RAMAN SPECTRA (?)TGA (?) BET. Transmission electron microscopy (TEM) observation demonstrated that the Ni-Al LDH nanowires were composed of nano-sized Ni-Al LDH sheets. This finding is different from the recent results that the nanowires have single crystal feature. Symmetric supercapatitors were prepared by using the graphene/Ni-Al LDH nanowires as electrode material. Compared to other Ni-Al LDH materials, the graphene/Ni-Al LDH nanowires exhibited much better performance as electrode material for supercapacitors, due to the preferentially conductive behavior of the nanowire structures and the conductive networks formed by the nanowires in the resultant electrodes.Meanwhile, the supercapacitor electrochemical performances based on those graphene materials were investigated systematically, which can open up a pathway and offer a technical support on the mass production of graphene materials and the fabrication of ultrathin high power/energy densities electric double layer capacitors and graphene based pseudo-capacitors.