Large-Scale and Facile Electrochemical Preparation of β-Co(OH)2 Nanocapsules and Investigation of their Supercapacitive Performance

A novel nanostructure of cobalt hydroxide (i.e. nanocapsule) was prepared via cathodic electrodeposition and its electrochemical performance was investigated using cyclic voltammetry and charge-discharge tests. The deposition experiments were performed in the pulse current mode (t(on) = 10 ms and t(off) = 10 ms) with applying the current density of 1 mA cm(-2) at low bath temperature of 10 degrees C. The structural and morphological characterization by XRD, IR, SET, TEM and BET techniques showed that the obtained deposit has single crystalline beta phase of Co(OH)(2) with high surface area capsule-like morphology. Mechanism of the beta-Co(OH)(2) nanocapsules was proposed and discussed. The electrochemical measurements displayed that the nanocapsules are capable to deliver specific capacitances' of 1243.1, 1170.8, 1050.5 and 908.5 Fg(-1) at the scan rates of 2, 5, 10 and 25 mV s(-1), respectively, within the potential range of -0.25-0.55 V (vs. Ag/AgCl). The results confirmed an excellent contribution of the nanocapsules in the redox reactions, suggesting the potential application in electrochemical supercapacitors. (C) 2013 The Electrochemical Society.