MoO_2/Reduced Graphene Oxide Composite Electrode with Improved Cycling Performance and High Capacitance for Supercapacitors

摘要

One-pot solvothermal route was employed in this study to prepare MoO_2/reduced graphene oxide (RGO) composite electrode materials using ethylene glycol (EG) as the reductant. The composition and micro-structure of this composite were studied by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) characterization. Through construction of composite electrode, the nanoscale MoO_2 component can be stabilized by RGO sheets so that improved cycling performance was realized. After 1000 consecutive charge/discharge cycles at a large current density of 20 Ag~(-1), the as-obtained MoO_2/RGO composite electrode can maintain 90% of the initial specific capacitance, which was better than single-component MoO_2 nanoparticulate electrode (81% retention ratio). Moreover, high specific capacitance and excellent rate performance can also be attained by MoO_2/RGO composite electrode materials. A specific capacitance of 434 Fg~(-1) normalized to the mass of the whole composite electrode material was delivered at 1 Ag~(-1). When the charge/discharge current was increased to 20 Ag~(-1), 338 Fg~(-1) was afforded with 22% capacitance loss.