Electrochemically reduced graphene oxides/nanostructured iron oxides as binder-free electrodes for supercapacitors

•Sandwich-like composites of nanostructured iron oxides and GO were prepared.•Electrochemically reduced GO and FeOx were directly used as binder-free electrodes.•GO can be reduced to ecrGO by a facile and controllable electrochemical method.•The composite has high Csp (∼235 F g−1) and good stability (93% after 2000 cycles).

In this work, a facile approach was applied to prepare composites of electrochemically reduced graphene (ecrGO) oxides and iron oxides (FeOx) as binder-free electrodes for enhancing the electrochemical performance of supercapacitors. The iron oxides were intercalated between the graphene oxides sheets to form sandwich-like composites, such composites were electrochemically reduced in an alkaline solution and directly used as electrodes without any binders. The as-obtained composite (ecrGO/FeOx) shows a good mechanical strength according to the SEM and Raman results, also exhibits high specific capacitance (Csp) of ∼235 F g−1 at a scan rate of 10 mV s−1 and good cycling stability of 92% retention after 2000 cycles in 1 M NaOH. Although there is a decline of Csp for the ecrGO/FeOx composite because of the high charge transfer resistance and poor conductivity of the iron oxides, it still possesses a higher Csp than ecrGO when the scan rate increases to 400 mV s−1. The relative high Csp and good stability of ecrGO/iron oxides composites due to the synergistic effect between ecrGO and iron oxides during the electrochemical processes, indicates it can be a promising candidate for supercapacitors.

Graphical abstractA sandwich-like composite of electrochemically reduced GO and iron oxides was prepared as a binder-free electrode. This composite with high specific capacitance and good stability can be a promising candidate for supercapacitors.Download high-res image (153KB)Download full-size image