Ultrafine Tin Dioxide Nanoparticles Grown on Nitrogen-doped Graphene with Rich Pyrrolic Nitrogen for Excellent Supercapacitor Performance

Composites of ultrafine tin dioxide nanoparticles grown on nitrogen-doped graphene (SnO2@NG) with high pyrrolic nitrogen content are successfully prepared via a one-step method by employing graphene oxide, tin chloride, and urea as raw materials. Morphology and microstructure of SnO2@NG are characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA), revealing evenly dispersed SnO2 nanoparticles on the surface of nitrogen-doped graphene sheets and a SnO2 content of 54.23%. The SnO2@NG electrode exhibits a specific capacitance of 289.5 F/g at a current density of 0.5 A/g in 0.5 mol/L Na2SO4 solution and retains 92.85% of its initial capacitance after 2000 charge/discharge cycles. These results prove that SnO2@NG is an excellent material for high-performance supercapacitors.