Enhancing energy storage by constructing poly(3,4-ethylenedioxythiophene)-encapsulated iron oxide/carbon nanotubes composites

Nanocomposites consisting of conducting polymers and metal oxide are promising material in electrochemical energy storage. The design of nanostructure is regarded as an efficient strategy to improve electron and ion transfer. However, the construction of nanocomposites usually needs multistep reaction. Herein, a poly(3,4-ethylenedioxythiophene)-encapsulated iron oxide/carbon nanotube nanocomposite (Fe 2 O 3 /CNTs@PEDOT) is demonstrated as an efficient anode for aqueous supercapacitors. The Fe 2 O 3 /CNTs nanocomposite is firstly constructed by a rapid combustion strategy, which provided electrode a good hydrophilic ability. The PEDOT is further in situ constructed on the surface of Fe 2 O 3 /CNTs by an electrochemical polymerization process for enhancing the cycling stability. The Fe 2 O 3 /CNTs@PEDOT electrode delivers an enhanced ions transfer and stability during the charge/discharge process. In 1 M Na 2 SO 4 , such Fe 2 O 3 /CNTs@PEDOT-180 s electrode delivers a specific capacitance of 1014 mF cm −2 at 2 mA cm −2 and retains 89.7% of initial capacitance at 20 mA cm −2 after 3000 cycles, which is superior than that of the Fe 2 O 3 /CNTs electrode (79.2%). The asymmetric aqueous supercapacitor consisted of Fe 2 O 3 /CNTs@PEDOT and MnO 2 /CC electrodes with an operating potential of 2.0 V reaches a high areal energy density of 0.207 mWh cm −2 at a power density of 2.0 mW cm −2 . Graphical abstract