Synthesis And Electrochemical Performance Of Nickel Hydroxide As The Electrode Material For Supercapacitor

Electrochemical capacitors (ECs), also called supercapacitors or ultracapacitors, have played an increasingly important role in power source applications because of their higher power density and longer cycle life than secondary batteries in addition to their higher energy density compared to conventional electrical double-layer capacitors. Nickel hydroxide (Ni(OH)2) is a promising electrode material for applications in ECs due to its well defined electrochemical redox activity and the possibility of enhanced performance through different preparative methods. Ni(OH)2has two polymorphs, a-Ni(OH)2and P-Ni(OH)2phase. Both of these phases have a hexagonal-layered structure and tend to form in thin flake or platelet shapes. a-Ni(OH)2is a hydroxyl-deficient phase with interlayer anions and water molecules, rather than a stoichiometric composition in β3-Ni(OH)2. However, under strong alkaline media, a-Ni(OH)2is unstable and quickly converts into (3-Ni(OH)2phase. Thus, a-Ni(OH)2is restricted in practical applications, although it has a high potential as an electrode material for applications in energy power storage devices.We report for the first time, a simple route to synthesize a novel coin-like structured nanocrystalline (3-nickel hydroxide electrode with high specific capacitance. The structure and morphology of as-prepared products are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results show that the products are typical β-nickel hydroxide with bunches coin-like nanoplates morphology. The electrochemical properties of coin-like β-Ni(OH)2are examined by cyclic voltammetric, chronopotentiometry and electrochemical impedance spectroscope. Cyclic voltammetric studies show that the electrodes have good reversibility. A specific capacitance of1532F g-1is obtained at a charge/discharge current density of0.2A g-1. After a continuous300cycles,81%of the specific capacitance (952F g-1) is remained. Thus, the strings of coin β-Ni(OH)2are a promising electrode material for ECs.In this paper, the nickel oxides are manufactured from the nickel hydroxides by calcinations, which are produced by the methods of CHP. Meanwhile, the prepared nickel oxides are made into the electrodes of anode of the lithium ion battery, for further exploring their electrochemical character.