One-step synthesis of iodine doped polyaniline-reduced graphene oxide composite hydrogel with high capacitive properties

Iodine doped polyaniline-reduced graphene oxide composite hydrogel was one-step synthesized using iodine as catalyst and dopant. The structure, composition and the surface morphology of the material were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), scanning electronmicroscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that the reduced graphene oxide was iodine-doped and covered uniformly by the polyaniline nanoparticles doped also with iodine. The electrochemical properties of the hydrogel were evaluated by cyclic voltammetry, galvanostatic charge/discharge and the impedance spectroscope using a symmetrical two-electrode configuration. With the enhanced specific capacitance as 712.5 F g−1 at a current density of 1 A g−1 and a good cycling stability about 77% (from 440 to 340 F g−1) after 1000 charge/discharge cycles at a current density of 8 A g−1, the composite hydrogel exhibits great potential in the application of high-performance energy storage devices.