Synthesis, characterization, and electrochemical properties of ultrafine β-Ni(OH)2 nanoparticles

Nickel hydroxide was deposited via cathodic electrodeposition from low-temperature 0.005 M NiCl2 bath without using any surfactant or template. The cathodic current density was 1 mA cm−2 and stainless steel was used as the cathode. The XRD pattern confirmed that the prepared sample has a pure brucite crystal phase of β-Ni(OH)2 and the broadening of diffraction peaks showed that the particles size of the prepared β-Ni(OH)2 is extremely small. Thermal behavior and composition of the prepared β-Ni(OH)2 were investigated by DSC-TG and FT-IR analyses. Morphological characterization by SEM and TEM revealed that β-Ni(OH)2 is composed of well dispersed ultrafine particles with size of about 5 nm. The electrochemical properties of the prepared nanoparticles were studied by means of cyclic voltammetry (CV) and galvanostatic charge–discharge tests in 1 M KOH. The prepared β-Ni(OH)2 nanoparticles showed excellent capacitance behavior of 740 F g−1 in the potential window of 0–0.55 V vs. Ag/AgCl. These results make the β-Ni(OH)2 nanoparticles as a promising candidate for the supercapacitor electrodes.