Microwave-assisted synthesis of layer-by-layer ultra-large and thin NiAl-LDH/RGO nanocomposites and their excellent performance as electrodes

Abstract

In this work, ultra-large sheet NiAl-layered double hydroxide (LDH)/reduced graphene oxide (RGO) nanocomposites were facilely synthesized via in situ growth of NiAl-LDH on a graphene surface without any surfactant or template. It was found that with a microwave-assisted method, NiAl-LDH nanosheets grew evenly on the surface of graphene. With this method, the formation of NiAl-LDH and reduction of graphene oxide were achieved in one step. The unique structure endows the electrode materials with a higher specific surface area, which is favorable for enhancing the capacity performance. The morphology and microstructure of the as-prepared composites were characterized by X-ray diffraction, Brunauer-Emmett-Teller surface area measurement, and transmission electron microscopy. The specific surface area and pore volume of the RGO/LDH composite are 108.3 m2 g−1 and 0.74 cm3 g−1, respectively, which are much larger than those of pure LDHs (19.8 m2 g−1 and 0.065 cm3 g−1, respectively). The capacitive properties of the synthesized electrodes were studied using cyclic voltammetry and electrochemical impedance spectroscopy in a three-electrode experimental setup. The specific capacitance of RGO/LDHs was calculated to be 1055 F g−1 at 1 A g−1. It could be anticipated that the synthesized electrodes will find promising applications as novel electrode materials in supercapacitors and other devices because of their outstanding characteristics of controllable capacitance and facile synthesis.