Influences of graphene oxide support on the electrochemical performances of graphene oxide-MnO2 nanocomposites

Abstract

MnO2 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 MnO2-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 MnO2, which lead to the fact that the loading amount of MnO2 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 MnO2 loading on GO(1). As the electrode of supercapacitor, MnO2-GO(1) nanocomposites show

larger capacitance (307.7 F g-1) and better electrochemical activity than MnO2-GO(2) possibly due to the high

loading, good uniformity, and homogeneous distribution of MnO2 on GO(1) support.