Glycerol-Assisted Synthesis and Electrochemical Properties of Co3O4 Nanowires

Cobalt oxide (Co3O4) nanowires were controllably synthesized using glycerol and Co(NO3)(2) as reagents and adjustment of the experimental parameters. The morphology and structure of the as-prepared 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 Co3O4 nanowire electrodes at low scan rates. The specific capacitance of the Co3O4 nanowire electrodes was 163 F.g(-1) at a current density of 1 A.g(-1), 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(-1) and 80% at 4 A.g(-1); it then decreased obviously with further increase in cycle number. In Li-ion battery measurements, Co3O4 nanowire electrodes showed a discharge capacitance of 1124 mAh.g(-1) which decreased rapidly during the cycle test. The formation mechanism and the relationship between the structure and electrochemical properties of Co3O4 nanowires were discussed based on the experimental results.