A Facile Method to Prepare Three‐Dimensional Fe 2 O 3 /Graphene Composites as the Electrode Materials for Supercapacitors

Metal oxides comprise an important class of electrode materials for supercapacitors. In this paper, we report the preparation of three‐dimensional (3D) Fe 2 O 3 /chemically converted graphene composites and their application in supercapacitors. The composites are synthesized via a one‐step reaction between graphene oxide and Fe 2+ at a mild condition. During the reaction graphene oxide sheets are reduced and self‐assemble into a 3D network, while Fe 2+ is converted into Fe 2 O 3 and deposited onto the graphene network. This structure facilitates the diffusion of the electrolyte and the electron transfer between Fe 2 O 3 and the current collector, thus endows the composites with high capacitive performance. A high specific capacitance of 264 F·g −1 (2.5 A·g −1 ) at the working potential of 0–−1 V vs. saturated calomel electrode is achieved on the Fe 2 O 3 /chemically converted graphene composites. Meanwhile, the composites show good cycling stability, with capacitance retention of 95.7% after 5000 cycles. This work provides a facile method to fabricate cathode materials for asymmetric supercapacitors.