Synthesis and supercapacitive behavior of carbon aerogel microbeads encapsulated by in situ Co3O4 nanoparticle

Co3O4/carbon aerogel microbead (Co3O4/CAMB) composites are prepared by in situ coating method and their supercapacitive behaviors are investigated. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectrum, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectrum are used to characterize the structure and morphology of Co3O4/CAMB. The results show that nano-sized Co3O4 particles are homogenously encapsulated on the surface of CAMB. Electrochemical performances of the composite electrodes with different Co3O4 amount are studied by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements. It is found that Co3O4/CAMB composites show better electrochemical performance than CAMB, and the optimum content of Co3O4 in Co3O4/CAMB composites is 10 wt.%. The specific capacitance of 10%-Co3O4/CAMB composite in 6 mol L-1 KOH electrolyte is about 350.18 Fg(-1) at a current density of 1 A g(-1). Moreover, 10%-Co3O4/CAMB composite supercapacitor exhibits relatively good high-rate capability and excellent cycle life. (C) 2011 Elsevier B.V. All rights reserved.