p-Phenylenediamine(PPD)functionalized graphene oxide(GO)materials(PPDG)were prepared through a one-step solvothermal process and their application as supercapacitors(SCs)were studied.The PPD is not only as the spacers to prevent aggregating and restacking of the graphene sheets in the preparing process but also as nitrogen sources to obtain the nitrogen-doped graphene.The structures of PPDG were characterized by Fourier transformed infrared spectroscopy(FT-IR),X-ray diffraction spectroscopy(XRD),Raman spectroscopy and X-ray photoelectron spectroscopy(XPS)and the results show that the nitrogen-doped graphene was achieved with nitrogen content as high as 10.85 at.%.The field emission scanning electron microscopy(FE-SEM)and high resolution transmission electron microscopy(HR-TEM)have confirmed that the morphologies of PPDG were loose layered with less aggregation,indicating that PPD molecules,as spacers,effectively prevent the graphene sheets from restacking during the solvothermal reaction.The special loose textures make PPDG materials exhibit excellent electrochemical performance for symmetric SCs with superior specific capacitance(313 F/g at 0.1 A/g),rate capability and cycling stability.The present synthesis method is convenient and may have potential applications as ultrahigh performance SCs.
Microwave-absorbing polymeric composites based on single-walled carbon nanotubes （SWNTs） are fabricated via a simple yet versatile method, and these SWNT-epoxy composites exhibit very impressive microwave absorption perfor- mances in a range of 2 GHz-18 GHz. For instance, a maximum absorbing value as high as 28 dB can be achieved for each of these SWNT-epoxy composites （1.3-mm thickness） with only 1 wt% loading of SWNTs, and about 4.8 GHz bandwidth, corresponding to a microwave absorption performance higher than 10 dB, is obtained. Furthermore, such low and appro- priate loadings of SWNTs also enhance the mechanical strength of the composite. It is suggested that these remarkable results are mainly attributable to the excellent intrinsic properties of SWNTs and their homogeneous dispersion state in the polymer matrix.
