Phytic Acid-Doped Cross-linked Polyaniline Nanofibers for Electrochemical Supercapacitor Electrode Applications

Electrochemical energy storage characteristics of chlorine- and phytic acid-doped polyaniline nanofibers (Cl- and Ph-PAni NFs), which were synthesized via radical polymerization in a hydrochloric acid and a Ph solution, respectively, were comparatively investigated. The Ph-PAni NFs showed a specific capacitance of 227 F g−1, which was two times higher than the value of 105 F g−1 for Cl-PAni NFs at 30 A g−1, due to the enhanced electrical conductivity caused by Ph doping. Moreover, the Ph-PAni NFs presented superior supercapacitor electrode performances in terms of charge-discharge cycle life, specific power, and electrochemical impedance. Diverse spectroscopic analyses revealed that the Ph doping contributed to formation of crosslinks between PAni backbones, which eventually provided many effective electrical conducting paths in the NFs. Thus, the high conductivity is responsible for the high electrochemical activity of Ph-PAni NFs. This approach to increase the electrochemical performances is expected to be applied to other conducting polymeric supercapacitor electrodes for more practical device applications.