No abstract

Open carbon nanotube materials with hierarchical porosity and N-doping are prepared from polyaniline nanotubes via a combination method of pre-carbonization and post-KOH activation. The morphology, pore texture and surface properties of the carbon materials are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 adsorption, X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The prepared carbon materials have a typical hierarchical pore texture and very high specific surface area up to 3253 m 2 g À1 . The electrochemical capacitive performance of the prepared carbons was systematically investigated in the 6 M KOH electrolyte. HPCT-4 exhibits high charge storage capacity with a specific capacitance of 365.9 F g À1 at a current density of 0.1 A g À1 , good rate capability of 60% in the range of 0.1-10 A g À1 , and excellent stability over 10 000 cycles. The high capacitive performance could be due to the hierarchical porosity combined with high effective surface area and heteroatom doping effects, resulting in both electrochemical double layer and Faradaic capacitance contributions.

No abstract

No abstract

Reduced graphene oxide aerogel (RGOA) is synthesized successfully through a simultaneous self-assembly and reduction process using hypophosphorous acid and I2 as reductant. Nitrogen sorption analysis shows that the Brunauer-Emmett-Teller surface area of RGOA could reach as high as 830 m2 g−1, which is the largest value ever reported for graphene-based aerogels obtained through the simultaneous self-assembly and reduction strategy. The as-prepared RGOA is characterized by a variety of means such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Electrochemical tests show that RGOA exhibits a high-rate supercapacitive performance in aqueous electrolytes. The specific capacitance of RGOA is calculated to be 211.8 and 278.6 F g−1 in KOH and H2SO4 electrolytes, respectively. The perfect supercapacitive performance of RGOA is ascribed to its three-dimensional structure and the existence of oxygen-containing groups.