Polyaniline nanofibers as the electrode material for supercapacitors

Doped polyaniline (PANI) nanofibers for use in supercapacitors were fabricated by the template method with the aid of ferric chloride (FeCl3) and ammonium persulfate (APS) as the oxidant, in which the organic composite fibers of methyl orange/FeCl3 (MO/FeCl3) functioned as the seed template. Transmission electron microscopy (TEM) revealed that PANI was a fiber in shape with a diameter of 20–40 nm and length of about 200–400 nm, and the template and oxidant played important roles in the formation of PANI nanofibers. The electrochemical performance of PANI electrode was evaluated by cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS). A high specific capacitance of 428 F g−1 was obtained within the potential range of −0.2 to 0.8 V in 1 M H2SO4 solution. Moreover, PANI electrode exhibited high discharge/charge efficiency of 93% and the capacitance retention of 83% at a current density of 5 mA cm−2, indicating good electrochemical reversibility and rate capability.