Hydrothermal synthesis of simonkolleite microplatelets on nickel foam-graphene for electrochemical supercapacitors

Abstract

Nickel foam-graphene (NF-G) was synthesized by chemical vapour deposition followed by facial in situ aqueous chemical growth of simonkolleite (Zn5(OH)8Cl2·H2O) under hydrothermal conditions to form NF-G/simonkolleite composite. X-ray diffraction and Raman spectroscopy show the presence of simonkolleite on the NF-G, while scanning and transmission electron microscopies show simonkolleite micro-plates like structure evenly distributed on the NF-G. Electrochemical measurements of the composite electrode give a specific capacitance of 350 Fg−1 at current density of 0.7 Ag−1 for our device measured in three-electrode configuration. The composite also shows a rate capability of ~87% capacitance retention at a high current density of 5Ag−1,which makes it a promising candidate as an electrode material for supercapacitor applications.