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Metal oxides comprise an important class of electrode materials for supercapacitors. In this paper, we report the preparation of three-dimensional (3D) Fe2O3/chemically converted graphene composites and their application in supercapacitors. The composites are synthesized via a one-step reaction between graphene oxide and Fe2+ at a mild condition. During the reaction graphene oxide sheets are reduced and self-assemble into a 3D network, while Fe2+ is converted into Fe2O3 and deposited onto the graphene network. This structure facilitates the diffusion of the electrolyte and the electron transfer between Fe2O3 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 Fe2O3/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. [ABSTRACT FROM AUTHOR]