Capacitance performance of nanostructured β-Ni(OH)_2 with different morphologies grown on nickel foam

摘要

Nanostructured β-Ni(OH)2 with different morphologies are successfully grown on nickel foam using a template-free method by adjusting the anions of nickel salt precursors. The morphology is examined by scanning electron microscopy and the phase structure is analyzed by X-ray diffraction (XRD). The surface area is calculated with the Brunauer-Emmet-Teller (BET) model and the pore size distribution is determined with the Barett-Joyner-Halenda (BJH) method. The microstructure of β-Ni(OH)_2 remarkably depends on the nickel salt precursors including Ni(NO_3)_2, NiCl_2 and NiSO_4. The electrochemical behaviours of β-Ni(OH)_2 electrodes are investigated by cyclic voltammetry, galvanostatic charge/discharge test and electrochemical impedance spectroscopy in 6 mol dm~(-3) KOH solution. Results show that the β-Ni(OH)_2/Ni-foam electrode prepared with NiSO_4 exhibits the largest specific capacitance (1025.3 F g~(-1) at a current density of 1.0 A g~(-1)), best reversibility and lowest charge transfer resistance due to its largest porosity and surface area.