Synthesis and characterization of polyoxometalate/graphene oxide nanocomposites for supercapacitor

Abstract

Nanomaterials, typically the graphene oxide (GO) nanosheets, which can be suggested for use in supercapacitor, have attracted increased attentions in the recent years, but looking for a feasible strategy that can simply and effectively modify their electrochemical performance still needs a long way to go. In this work, we have designed and reported a kind of GO/phosphomolybdic acid (PMo) nanocomposite that can exhibit modified electrochemical performance, through dispersing the GO nanosheets into the aqueous (PMo) solution. Various techniques, such as X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectra, energy dispersive X-ray (EDS) anlysis, galvanostatic charge-discharge (GCD), and cyclic voltammetry (CV), have been used to characterize the structure and electrochemical performance of GO/PMo nanocomposites. Our results confirm the successful implantation of the PMo clusters on the GO nanosheets and, in the meanwhile, reveal that anchoring PMo clusters on the surface of GO nanosheets can greatly enhance the specific capacitance (Cs) and cycling stability of GO/PMo nanocomposites. More specifically, the Cs value of GO/PMo nanocomposites after 5000 GCD cycles is found to be ~160% higher than that of GO. More than that, we also find that the resting temperature (T), which can affect the adjustment in the orientation of PMo anions during the implanting process, has a significant influence on the interaction between the PMo clusters and GO nanosheets. This work not only presents the GO/PMo nanocomposites, but also provides some new ideas for researchers to modify the electrochemical performance of other nanomaterials that can be potentially used for supercapacitor, not just limited to the GO nanosheets we showed here.