Influences of graphene oxide support on the electrochemical performances of graphene oxide-MnO(2 )nanocomposites

MnO(2 )supported on graphene oxide (GO) made from different graphite materials has been synthesized and further investigated as electrode materials for supercapacitors. The structure and morphology of MnO(2)-GO nanocomposites are characterized by X-ray diffraction, X-ray photoemission spectroscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and Nitrogen adsorption-desorption. As demonstrated, the GO fabricated from commercial expanded graphite (denoted as GO(1)) possesses more functional groups and larger interplane gap compared to the GO from commercial graphite powder (denoted as GO(2)). The surface area and functionalities of GO have significant effects on the morphology and electrochemical activity of MnO(2), which lead to the fact that the loading amount of MnO(2 )on GO(1) is much higher than that on GO(2). Elemental analysis performed via inductively coupled plasma optical emission spectroscopy confirmed higher amounts of MnO(2 )loading on GO(1). As the electrode of supercapacitor, MnO(2)-GO(1) nanocomposites show larger capacitance (307.7 F g(-1)) and better electrochemical activity than MnO(2)-GO(2) possibly due to the high loading, good uniformity, and homogeneous distribution of MnO(2 )on GO(1) support.