Flexible graphene/MnO2 composite papers for supercapacitor electrodes

Graphene/manganese dioxide (MnO2) composite papers (GMCP) are fabricated via a simple three-step route: preparation of graphene oxide/MnO2 composite (GOMC) dispersion, subsequent vacuum filtration of GOMC dispersion to achieve graphene oxide/MnO2 composite paper (GOMCP), and finally thermal reduction of GOMCP to generate GMCP. The morphology and microstructure of the prepared samples are characterized by field-emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, Fourier transformation infrared spectroscopy, thermal gravimetric analysis and X-ray photoelectron spectroscopy. Moreover, as a binder-free and flexible electrode material for supercapacitors, the electrochemical properties of the prepared GMCP are evaluated by cyclic voltammetry and galvanostatic charge/discharge tests. As a result, the specific capacitance of the GMCP with the MnO2 weight ratio of 24% (GMCP-24) reaches 256 F g(-1) at a current density of 500 mA g(-1) and also shows good cycle stability, indicating a promising potential application as an effective electrode material for supercapacitors.