Facile One-pot Synthesis of Freestanding Carbon Nanotubes on Cellulose-derived Carbon Films for Supercapacitor Applications: Effect of the Synthesis Temperature

Freestanding carbon nanotubes (CNTs) on cellulose–derived carbon films could be produced in one step by a chemical vapor deposition (CVD) method using nickel/nickel oxide (Ni/NiO) nanocomposite supported on the carbon film as a catalyst. Ethanol was used as a carbon source and nitrogen gas was used a carrier gas. The influence of synthesis temperature on the structural and electrochemical properties of the resulting CNTs on the carbon films was studied. The synthesized CNTs on the carbon films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X–ray diffraction (XRD), Raman spectroscopy, and Bruneur–Emmet–Teller (BET) methods. From these investigations, the structure of the CNTs attached on the carbon film tends to become more graphitic upon the increase in the synthesis temperature. The electrochemical behaviors of the samples were determined by cyclic voltammetry (CV) and galvanostatic charge–discharge in a three-electrode cell. The CNTs grown on the carbon film at 600 °C provided the highest specific capacitance value (484.34 F/g) at the current density of 2 A/g and the highest energy density of 46.34 Wh/kg at the power density of 0.83 kW/kg.