A novel solvothermal synthesis of Mn3O4/graphene composites for supercapacitors

Mn3O4/graphene (GM) composites were prepared via a simple solvothermal process by mixing Mn(AC)(2)center dot 4H(2)O and graphite oxide (GO) suspension in mixed ethanol/H2O. As characterized by scanning electron microscopy and transmission electron microscopy, Mn3O4 nanoparticles with size of 37-50 nm are effectively anchored in graphene sheets. Cyclic voltammetry and galvanostatic charge-discharge measurements were adopted to investigate the electrochemical properties of GM composites in 1.0 M Na2SO4 solution. In a potential window of -0.2 to 0.8 V vs. SCE, the composites deliver an initial specific capacitance of 161.0 F g(-1) at 1 A g(-1) and increase to 230 F g(-1) after 1000 cycles, while significant capacitance fading for pure Mn3O4. At a high current density of 5 A g(-1), the specific capacitances of 116 F g(-1), 22.5 F g(-1) are exhibited for the Mn3O4/graphene composites and pure Mn3O4, respectively, indicating that graphene greatly enhances the electrochemical performance of Mn3O4. (C) 2012 Elsevier Ltd. All rights reserved.