Sulfur and nitrogen-doped graphene quantum dots/PANI nanocomposites for supercapacitors

• Published in: New journal of chemistry Vol. 45; no. 8; p. 411
• Main Authors: Kuzhandaivel, Hemalatha, Manickam, Sornalatha, Balasingam, Suresh Kannan, Franklin, Manik Clinton, Kim, Hee-Je, Nallathambi, Karthick Sivalingam
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.03.2021
• Subjects: Aniline; Capacitance; Current density; Electrical resistivity; Electroactive materials; Energy storage; Flux density; Fourier transforms; Graphene; Infrared analysis; Ion storage; Nanocomposites; Nitrogen; Particulate composites; Polyanilines; Quantum dots; Sulfur
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d1nj00038a

Sulfur and nitrogen-doped graphene quantum dots/polyaniline (S,N-GQDP) nanocomposites are prepared by a two-step synthesis method. The heteroatoms (sulfur and nitrogen) doped graphene quantum dots (S,N-GQDs) are first prepared by a hydrothermal method and then mixed with aniline at three different concentrations, followed by polymerization to form S,N-GQDP1, S,N-GQDP2 and S,N-GQDP3 nanocomposites. Various physicochemical characterization techniques are used to confirm the formation of S,N-GQDs and their interaction with polyaniline (PANI) in S,N-GQDP nanocomposites. Fourier transform infrared (FTIR) and Raman spectral analyses confirm the delocalization of electrons in the polymer backbone of S,N-GQDP through electrostatic interaction and the π-π interaction between S,N-GQDs and pristine PANI. The pristine PANI and the three-different nanocomposites are used as electroactive materials to assess the energy storage properties. The S,N-GQDP2 composite has pine cone shape-like particles with a high surface area (154 m 2 g −1 ). The doping of heteroatoms improves the electrical conductivity and increases the reactive sites that act as trap sites for enhanced ion storage. The S,N-GQDP2 nanocomposite shows a highest specific capacitance of 645 F g −1 at a current density of 0.5 A g −1 in the three-electrode configuration. The S,N-GQDP2 composite-based symmetric cell shows an energy density of 17.25 Wh kg −1 (corresponding device capacitance of 124.2 F g −1 at a current density of 1 A g −1 ) at a power density of 500 W kg −1 . A high volumetric energy density of 18.11 Wh L −1 is obtained at a volumetric power density of 525 W L −1 . In addition, the S,N-GQDP2 nanocomposite-based symmetric device shows good cycling stability for 1000 cycles with a capacitance retention of 90%. Sulfur and nitrogen-doped graphene quantum dots/polyaniline nanocomposites were synthesized and their electrochemical charge storage properties were tested for supercapacitor applications.