Graphene/Polyaniline Nanofiber Composites as Supercapacitor Electrodes

Abstract

Chemically modified graphene and polyaniline (PANI) nanofiber composites were prepared by in situ polymerization of aniline monomer in the presence of graphene oxide under acid conditions. The obtained graphene oxide/PANI composites with different mass ratios were reduced to graphene using hydrazine followed by reoxidation and reprotonation of the reduced PANI to give the graphene/PANI nanocomposites. The morphology, composition, and electronic structure of the composites together with pure polyaniline fibers (PANI-F), graphene oxide (GO), and graphene (GR) were characterized using X-ray diffraction (XRD), solid-state 13 C NMR, FT-IR, scanning electron microscope (SEM), transmission electron microscope (TEM), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). It was found that the chemically modified graphene and the PANI nanofibers formed a uniform nanocomposite with the PANI fibers absorbed on the graphene surface and/or filled between the graphene sheets. Such uniform structure together with the observed high conductivities afforded high specific capacitance and good cycling stability during the charge-discharge process when used as supercapacitor electrodes. A specific capacitance of as high as 480 F/g at a current density of 0.1 A/g was achieved over a PANI-doped graphene composite. The research data revealed that high specific capacitance and good cycling stability can be achieved either by doping chemically modified graphenes with PANI or by doping the bulky PANIs with graphene/graphene oxide.

Graphene/polymer composites for energy applications

“…Among them, PANI and PPy have been paid the most intensive attention because of their fast electrochemical reactions, low cost, and high specific capacitances. 7,80,90,[133][134][135] However, CP electrodes exhibit large volume changes during the doping/ dedoping processes, so the electrodes degrade and the electrochemical performance diminishes during cycling tests. 130 Adding graphene to the polymers can improve the mechanical and electrochemical cycling stability of CP electrodes.…”

“…Zhang et al made a homogenous aqueous solution of aniline and GO. 90 After the polymerization, GO sheets in the composite were reduced by hydrazine. The specific capacitance of the supercapacitor was measured to be 480 F g À1 at a current density of 0.1 A g À1 .…”

Tert-butylhydroquinone-decorated graphene nanosheets and their enhanced capacitive behaviors

“…Furthermore, excellent rate capability and cycling ability are achieved using the TBHQ-decorated graphene nanosheet electrode. To improve the capacitive behavior of graphene-based materials further, only a few studies have investigated the use of graphene coupled with conducting polymers [8][9][10][11]. Also, some researchers are trying to introduce the transition metal oxides/hydroxides with high theoretical specific capacitances into graphene systems [12][13][14][15][16].…”

Clicking graphene oxide and Fe3O4 nanoparticles together: an efficient adsorbent to remove dyes from aqueous solutions

“…The as-prepared GO by modified Hummers' method (Zhang et al 2010b), (100 mg) was well dispersed in 1 mL of dry DMF by sonification for 1 h and then was treated with SOCl 2 (20 mL) at 80°C for 3 days. After removing the excess of SOCl 2 under reduced pressure, propargyl alcohol (2 mL), distilled CH 2 Cl 2 (2 mL) and Et 3 N (1 mL) were added dropwise to GO at 0°C.…”