Facile synthesis of specific FeMnO3 hollow sphere/graphene composites and their superior electrochemical energy storage performances for supercapacitor

In this study, FeMnO3 hollow sphere/reduced graphene oxide (RGO) composites are fabricated using simple aging reaction followed by a thermal-treatment process. The as-prepared samples are well-characterized utilizing powder X-ray diffraction (XRD), Scan electron microscope (SEM), Transmission electron microscope (TEM), X-ray photoelectron spectrum (XPS), and Raman spectra techniques. The results demonstrate that the prepared FeMnO3 samples undergo specific morphology transition from hollow spheres to solid rod-like aggregates, as accompanied by enhanced crystallization with increasing calcination temperature. Moreover, the prepared FeMnO3/RGO composites are employed as the electrode for supercapacitor. Electrochemical measurement results indicate that the FeMnO3/RGO electrode displays a significantly enhanced specific capacitance of 189 F g(-1) and an improved cycling lifetime. The likely cause is the synergetic effects between the hollow spherical structure and the high conductivity of RGO. More importantly, the presented synthetic approach is facile, controllable, and reproducible, which could represent a promising avenue for preparing other ferrite-based composites with tailored morphologies and surface textures. (C) 2013 Elsevier B.V. All rights reserved.