Fabrication and characterization of polyaniline coated carbon nanofiber for supercapacitor

Polyaniline coated carbon nanofiber was fabricated using one-step vapor deposition polymerization technique. Fourier transform infrared (FT-IR) spectra and transmission electron microscope (TEM) images indicated that uniform and ultrathin conducting polymer layers were formed on the carbon nanofiber surfaces regardless of the coating thickness. It was also confirmed that the thickness of polyaniline layer could be conveniently tuned by the feeding amount of monomer. The coating thickness was dependent on initiator/monomer ratio, the vacuum pressure of reaction chamber and polymerization temperature. Among them, the vacuum pressure was a major factor to control the coating thickness of polyaniline onto the carbon nanofiber surface. In addition, the electrochemical analysis demonstrated that polyaniline coated carbon nanofiber showed an improved performance as supercapacitor. The specific capacitance of polyaniline coated carbon nanofiber exhibited a maximum value of 264 F/g when the thickness of polyaniline layer was ca. 20 nm.