Synthesis and characterization of different morphologies of Ni(OH)2 nanocrystals by a gas-liquid diffusion method at room temperature and supercapacitive properties

In this work, Ni(OH)2 nanocrystals have been synthesized via a gas-liquid diffusion method at room temperature in the absence of any template or organic surfactant. The structure and morphology of as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), BET specific surface area and pore size distribution analyzer. It can be observed that the crystal phase, morphology and specific surface area of as-prepared samples can be controlled by altering the concentration of NiSO4 solution and reaction time. The electrochemical supercapacitive properties of Ni(OH)2 nanostructures prepared at different concentration of NiSO4 solution have been investigated by cyclic voltammetry and chronopotentiometry. Chronopotentiometry test results showed that Ni(OH)2 samples prepared with 0.1 M NiSO4 solution exhibited a highest specific capacitance of 1799 F g−1 at a current density of 4 A g−1 within the potential range of 0-0.5 V and the Ni(OH)2 samples retain 92.8% of the initial capacitance even after 2000 continuous charge-discharge cycles. The higher capacitance and excellent recycle ability indicate that Ni(OH)2 crystals prepared by the gas-liquid diffusion method are suitable for supercapacitor materials.