Synthesis and super capacitance of goethite/reduced graphene oxide for supercapacitors

We report a one-step fabrication of alpha-iron oxyhydroxide/reduced graphene oxide (alpha-FeOOH/rGO) composites, in which the ferrous sulfate (FeSO4 center dot 7H(2)O) are used as the iron raw and reducing agent to grow goethite (alpha-FeOOH) and reduce graphite oxide (GO) to rGO in the same time. The morphology, composition and microstructure of the as-obtained samples are systematically characterized by thermogravimetric (TG) analysis, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and FT-IR. Moreover, their electrochemical properties are investigated using cyclic voltammetry and galvanostatic charge/discharge techniques. The specific capacitance of 452 F g(-1) is obtained at a specific current of 1 A g(-1) when the mass ratio of alpha-FeOOH to rGO is up to 80.3:19.7. In addition, the alpha-FeOOH/rGO composite electrodes exhibit the excellent rate capability (more than 79% retention at 10 A g(-1) relative to 1 A g(-1)) and well cycling stability (13% capacitance decay after 1000 cycles). These results suggest the importance and great potential of alpha-FeOOH/rGO composites in the applications of high-performance energy-storage. (c) 2013 Elsevier B.V. All rights reserved.