Facile Synthesis of Co3O4/Mildly Oxidized Multiwalled Carbon Nanotubes/Reduced Mildly Oxidized Graphene Oxide Ternary Composite as the Material for Supercapacitors

A three-dimensional (3D) Co3O4/mildly oxidized multiwalled carbon nanotubes (moCNTs)/reduced mildly oxidized graphene oxide (rmGO) ternary composite was prepared via a simple and green hydrolysis-hydrothermal approach by mixing Co(Ac)(2)center dot 4H(2)O with moCNTs and mGO suspension in mixed ethanol/H2O. As characterized by scanning electron microscopy and transmission electron microscopy, Co3O4 nanoparticles with size of 20-100 nm and moCNTs are effectively anchored in mGO. Cyclic voltammetry and galvanostatic charge-discharge measurements were adopted to investigate the electrochemical properties of Co3O4/moCNTs/rmGO ternary composite in 6 M KOH solution. In a potential window of 0-0.6 V vs. Hg/HgO, the composite delivers an initial specific capacitance of 492 F g(-1) at 0.5 A g(-1) and the capacitance remains 592 F g(-1) after 2000 cycles, while the pure Co3O4 shows obviously capacitance fading, indicating that rmGO and moCNTs greatly enhance the electrochemical performance of Co3O4.