Abstract
Iron-oxide (Fe(2)O(3)) nanoneedles were first in situ grown on the surface of carbon nanofibers (CNFs) using hydrothermal and N(2) annealing process, and then polyaniline (PANI) was coated on the Fe(2)O(3) nanoneedles to form network-like nanorods through dilute solution polymerization. The PANI/Fe(2)O(3)/CNFs binder-free electrode exhibited a high specific capacitance of 603 F/g at 1 A/g with good rate capability. (The capacitance loss was about 48.3% when the current density increased from 1.0 to 5.0 A/g.) It was caused by the fact that the PANI/Fe(2)O(3)/CNFs with a well-connected structure could provide a continuous electron transport path and improve the conductivity of the entire electrode. The solid-state hybrid PANI/Fe(2)O(3)/CNFs∥PANI/Fe(2)O(3)/CNFs symmetric device also achieved a high energy density of 29.85 Wh/kg at a power density of 500 W/kg. This universal compatible synthetic method for the PANI/Fe(2)O(3)/CNFs electrode could extend to other supercapacitor electrode systems, making it easy to fabricate various ternary electrodes for supercapacitors.