Cobalt hydroxide ultra-fine nanoparticles with excellent energy storage ability

摘要

Pulse current deposition was applied for the first time in the cathodic electrodeposition of cobalt hydroxide from nitrate bath and ultrafine nanoparticles of β-Co(OH)_2 were prepared via this route. The crystal structure and morphology of the prepared Co(OH)_2 were analyzed by X-ray diffraction spectroscopy, scanning and transmission electron microscopes. The XRD analysis revealed that the deposited hydroxide has a pure brucite-like phase of Co(OH)_2. Morphological characterization by SEM and TEM revealed that the prepared β-Co(OH)_2 is composed of well-dispersed ultrafine particles with size of about 5 nm. The energy storage ability of the prepared nanoparticles was studied by means of cyclic voltammetry (CV) and galvanostatic charge-discharge tests in 1 M KOH. The nanoparticles showed an excellent energy storage ability, where they delivered an energy density of 0.105 Wh/g with coulombic efficiency of 91.8%. Result of this work showed that pulse current cathodic electrodeposition can be recognized as a facile route for the preparation of very fine nanoparticles of cobalt hydroxide.