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We herein report a synthesis nitrogen-doped graphite oxide (N-doped GO) by heat treatment with melamine. The N-doped GO contains 4 at % of nitrogen, incurring the oxygen reduction reaction by nitrogen functional groups. Two kinds of aqueous electrolytes are used for finding the electrocatalytic activities, resulting in symmetric oxygen reduction reaction peaks at −0.8 and 0 V in 6 M KOH and 1 M H 2 SO 4 electrolytes, respectively. The N-doped GO is more activated in the acid electrolyte compared to thermally reduced graphite oxide (TrGO). Specific volumetric capacitance of N-doped GO in 1.8 M tetraethylmethylammonium tetrafluoroborate electrolyte is 57.4 F cc −1 which is higher than 30.5 F cc −1 of the TrGO, demonstrating positive effects of the nitrogen doping in the organic electrolytes for the energy storage devices.

An ultrathin V2O5 layer was electrodeposited by cyclic voltammetry on a self-standing carbon-nanofiber paper, which was obtained by stabilization and heat-treatment of an electrospun polyacrylonitrile (PAN)-based nanofiber paper. A very-high capacitance of 1308 F g−1 was obtained in a 2 M KCl electrolyte when the contribution from the 3 nm thick vanadium oxide was considered alone, contributing to over 90% of the total capacitance (214 F g−1) despite the low weight percentage of the V2O5 (15 wt%). The high capacitance of the V2O5 is attributed to the large external surface area of the carbon nanofibers and the maximum number of active sites for the redox reaction of the ultrathin V2O5 layer. This ultrathin layer is almost completely accessible to the electrolyte and thus results in maximum utilization of the oxide (i.e., minimization of dead volume). This hypothesis was experimentally evaluated by testing V2O5 layers of different thicknesses.

Oxydianiline-pyromellitic dianhydride poly(amic acid) (ODA-PMDA PAA) was polymerized with a catalyst support of triethyl amine for controlling molecular weight. This polymer was used for electrospinning in the preparation of PAA nanofibers, a precursor of carbon nanofibers. Here the amount of catalyst and concentration of PAA solution were optimized to produce polyimide-based carbon nanofibers approximately 80 nm in diameter. The effects of molecular weight of PAA, bias voltage, and spinning rate on the morphology of electrospun PAA and polyimide nanofibers have been evaluated. We showed that the conductivity of the carbon nanofiber mat decreased with increasing nanofiber diameter, where the conductivity of polyimide-based carbon nanofiber mat was much higher than those of other types of carbon nanofiber mat. The key ingredient to increase conductivity in a carbon nanofiber mat was found to be the number of cross junctions between nanofibers.

The electrospinning process has been used successfully to fabricate the multiwalled carbon nanotubes (MWCNTs)-embedded polyacrylonitrile (PAN) nanofiber paper. The diameters of nanofibers decreased with increasing CNT concentration. We found large anisotropic electrical conductivity, i.e., the electrical conductivity of the carbonized nanofiber paper along the spinning direction was about three times larger than that normal to the spinning direction, in good contrast with observations that the carbonized PAN nanofiber paper without CNTs did not reveal anisotropy in electrical conductivity. This proves that CNTs in PAN nanofiber were preferentially aligned along the nanofiber axis, in excellent agreements with transmission electron microscopy observations.

We propose a new material for high power and high density supercapacitors with excellent cycle stability. Graphite oxide (PSS-GO) intercalated with poly(sodium 4-styrensulfonate) showed high performance of electric double layer capacitance (EDLC) compared to that of the pristine graphite oxide. Specific capacitance of the PSS-GO reached 190 F/g, and the energy density was much improved to 38 Wh/kg with a power density of 61 W/kg. Cycle test showed that the specific capacitance decreased by only 12% after 14860 cycles, providing excellent cyclic stability. The high EDLC performance of PSS-GO composite was attributed to the wide interlayer distance and simple pore structures accommodating fast ion kinetics.

We describe the low-temperature thermal exfoliation of graphite oxide to obtain functionalized graphene sheets (FGSs). Graphite oxide, which is highly oxidized graphite produced by a modified Brodie method, is further exfoliated by a simple heat treatment at 270‐275 ◦ C under ambient Ar. The FGSs that are generated have fewer defects and less oxygen content than in commercial graphene sheets (GSs) prepared at high temperatures (>900 ◦ C). X-ray photoelectron spectroscopy demonstrates a clear π-plasmon peak in the FGSs of the type that is seen in precursor graphite, but not in commercial GSs. Thus, our FGSs exhibit high 2D crystallinity and minimal defects. (Some figures in this article are in colour only in the electronic version)

We propose a new chemical route for forming ultramicropores in carbon nanofibers by using a pore former, camphor, in electrospun polyacrilnitrile nanofibers. The resulting carbon nanofibers form mostly ultramicropores. Total specific surface area was 886 m(2) g(-1), which is similar to the activated carbon nanofibers in CO(2) and steam activation.

Carbon nanotubes-supported Pt nanoparticles were loaded using a microwave oven on the defective carbon nanotubes generated by an additional oxidant during acid treatment. The authors’ Raman spectra and x-ray diffraction analysis demonstrated that defects created during oxidation and microwave treatment acted as nucleation seeds for Pt adsorption. The generated Pt nanoparticles had the size distributions of 2–3nm and were uniformly distributed on the defects of carbon nanotubes. The authors’ density functional calculations showed that the adsorption of Pt atom on the vacancy of nanotube was significantly stronger by s-p hybridization with carbon atoms near the defect site.