Sub-nanometer,Ultrafine α-Fe2O3 Sheets Realized by Controlled Crystallization Kinetics for Stable,High-Performance Energy Storage |
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Authors: | Cancan Wang Dr Long Zhang Dr Mengxiong Li Dr Jiajia Zhang Yufei Chen Dr Minqiang Sun Dr Lei Dong Prof Hongbin Lu |
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Institution: | 1. State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Collaborative Innovation Center of Polymers and Polymer Composites, Fudan University, 2005 Songhu Road, Shanghai, 200438 P.R. China;2. School of Physical Science and Technology, ShanghaiTech University, 393 Huaxia Road, Shanghai, 201210 P.R. China |
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Abstract: | The development of energy devices based on iron oxides/hydroxides is largely hindered by their poor conductivity and large volume changes, especially with regard to specific capacitance and cycle stability. Herein, superior capacitance (1575 F g?1 at 1.25 A g?1) and high rate performance (955 F g?1 at 25 A g?1) were realized by synthesizing sub-nanometer, ultrafine α-Fe2O3 sheets loaded on graphene (SU-Fe2O3-rGO). An assembled asymmetric supercapacitor showed outstanding cycle stability (106 % retention after 30 000 cycles). This excellent performance arises from the unique structural characteristics of the α-Fe2O3 sheets, which not only enrich electrochemically reactive sites, but also largely eliminate the volume changes after long-term charge/discharge cycling. The synthesis of SU-Fe2O3-rGO critically depends on control of the crystallization kinetics during growth. A controlled heterogeneous nucleation mechanism results in the formation of atomically thin α-Fe2O3 sheets on graphene rather than large particles in solvent, as clarified by theoretical calculations. This strategy paves a new way to synthesizing atomically thin transition metal oxide sheets and low-cost, eco-friendly iron-based energy storage. |
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Keywords: | crystal growth electrochemistry iron oxides nanosheets energy storage |
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