Glycerol-Assisted Synthesis and Electrochemical Properties of Co<sub>3</sub>O<sub>4</sub> Nanowires

Abstract

Cobalt oxide (Co O ) nanowires were controllably synthesized using glycerol and Co(NO ) as reagents and adjustment of the experimental parameters. The morphology and structure of the asprepared products were characterized by a series of techniques such as X-ray podwer diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Electrochemical performance of the nanowires was studied by cyclic voltammetry (CV) and galvanostatic charge-discharge measurements. It was found that two pairs of redox peaks appeared in the CV curves of Co O nanowire electrodes at low scan rates. The specific capacitance of the Co O nanowire electrodes was 163 F·g at a current density of 1 A·g , according to the galvanostatic charge-discharge measurements. Cycle stability tests showed that the specific capacitance increased over the first tens of cycles and then reduced slowly. After 1000 cycles, the capacitance retention was over 98% at 1 A·g and 80% at 4 A·g ; it then decreased obviously with further increase in cycle number. In Li-ion battery measurements, Co O nanowire electrodes showed a discharge capacitance of 1124 mAh·g which decreased rapidly during the cycle test. The formation mechanism and the relationship between the structure and electrochemical properties of Co O nanowires were discussed based on the experimental results.