Carbon nanofibers with radially grown graphene sheets derived from electrospinning for aqueous supercapacitors with high working voltage and energy density

Abstract

Improvement of energy density is an urgent task for developing advanced supercapacitors. In this paper, aqueous supercapacitors with high voltage of 1.8 V and energy density of 29.1 W h kg(-1) were fabricated based on carbon nanofibers (CNFs) and Na2SO4 electrolyte. The CNFs with radially grown graphene sheets (GSs) and small average diameter down to 11 nm were prepared by electrospinning and carbonization in NH3. The radially grown GSs contain between 1 and a few atomic layers with their edges exposed on the surface. The CNFs are doped with nitrogen and oxygen with different concentrations depending on the carbonizing temperature. The supercapacitors exhibit excellent cycling performance with the capacity retention over 93.7% after 5000 charging-discharging cycles. The unique structure, possessing radially grown GSs, small diameter, and heteroatom doping of the CNFs, and application of neutral electrolyte account for the high voltage and energy density of the present supercapacitors. The present supercapacitors are of high promise for practical application due to the high energy density and the advantages of neutral electrolyte including low cost, safety, low corrosivity, and convenient assembly in air.

Highly Porous Nitrogen-Doped Carbon Nanofibers as Efficient Metal-Free Catalysts toward the Electrocatalytic Oxygen Reduction Reaction

“…1b, 34 Graphitic N atoms have the same configuration as graphitic carbon atoms, but they could introduce extra electrons in the delocalized π-system, showing a nucleophilic attack on oxygen. 1a, 35 ANCNF-800 has the largest limiting current density of −5.49 mA cm −2 among these activated samples, higher than those reported values of electrospun carbon fibers 22,36 and CNFs treated in NH 3 (Table S1), 20a and comparable to those of N-doped graphene materials prepared by annealing polypyrrole/GO, polyaniline/GO, NH 3 /GO, etc.…”

Nitrogen-doped activated carbon with micrometer-scale channels derived from luffa sponge fibers as electrocatalysts for oxygen reduction reaction with high stability in acidic media

“…The C900NH 3 also exhibits considerable adsorption capacity despite no activation process. This should be caused by the rough surface generated by the etching reaction of NH 3 during carbonization [27,28]. After activation, both the AC750NH 3 and AC900NH 3 show much higher N 2 adsorption capacity than the C900NH 3 .…”

“…This is caused by the high reactivity of NH 3 , which can produce active species such as atomic H, NH, and NH 2 by dissociation at high temperature. These active species can bond with the carbon atoms, increasing their mobility and thus promoting the crystallizing process [27,28]. The Raman spectra of the different samples are shown in Fig.…”

Fabrication, structure and mechanism of reduced graphene oxide-based carbon composite films

“…The (002) peak of the carbonized films of pure PI films became narrower and sharper. It indicated that their structures were near to that of graphite at 2θ=26.1 o [29]. 15 Meanwhile, the d-spacings calculated from (002) peaks of RGO/C composite films were 3.639, 3.735, and 3.867Å, for GO contents of 0.5wt%, 1wt% and 2wt%, respectively.…”