Tin Oxide/Nitrogen‐Doped Graphene Quantum Dots Composite Nanotubes: An Efficient Electrode for Supercapacitors

Abstract

Tin oxide (SnO2) and nitrogen‐doped graphene quantum dots (N‐GQDs) composite nanotubes (SnO2/N‐GQD NTs) were fabricated by the electrospinning technique and followed by the thermal annealing method for the application in supercapacitor as an electrode. SnO2/N‐GQD NTs with different ratio of N‐GQDs were prepared by adding different ratios of N‐GQDs along with tin chloride during the electrospinning process. The prepared composite's structure and morphological properties were characterized by using different techniques like XRD, FE‐SEM, TEM, and XPS. The supercapacitor performance of the SnO2/N‐GQD NTs composite was analyzed by the electrochemical studies such as cyclic voltammetry and galvanostatic charge‐discharge (GCD) measurement in 2 M KOH solution as electrolyte. The electrochemical analyses of SnO2/N‐GQD NTs was tested at different scan rates and current densities. SnO2/N‐GQD NTs prepared using 3 wt.% of N‐GQDs showed an excellent capacity retention even after 5000 GCD cycles and exhibited a maximum specific capacitance of 420 mF g-1 at a current density of 8 mA cm-2 in comparison to pure SnO2 NTs (230 mF cm-2).