Single-crystalline α-Fe2O3 nanohexahedron as outstanding anode material for lithium-ion batteries
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In this paper, single-crystalline hexahedron hematite is successfully obtained by a simple hydrothermal approach with assistance of PVP as surfactant. SEM and XRD results show that the as-obtained α-Fe2O3 has a nanohexahedron shape with high uniformity and high crystallinity. The effects of a few factors influencing the morphology of α-Fe2O3, such as PVP amount, reaction temperature, etc., are investigated carefully. More importantly, time-dependent experiments are carried out to have in-depth insight into the formation of the single-crystalline α-Fe2O3 nanohexahedron. Based on the full characterization of as-obtained α-Fe2O3, it is concluded that PVP as surfactant plays an important role in the formation of the hexahedron shape of α-Fe2O3. Besides, the proposed formation mechanism of α-Fe2O3 nanohexahedron is that the shape of α-Fe2O3 evolves from the nuclei, needle-like shapes, and urchin-like aggregates to the hexahedron shape, driven by minimization of surface energy and Ostwald ripening. When used as an anode material for lithium-ion batteries, nanohexahedron α-Fe2O3 shows a high rate capability. Moreover, after 150 cycles, the storage capacity of α-Fe2O3 is still up to 680 mAh g−1 and almost remains unchanged, suggesting high cyclability.
KeywordsIron oxide Hydrothermal method PVP Anode material Lithium-ion batteries Energy storage
We acknowledge financial support from the National Natural Science Foundation of China (No. 21601144), Xi’an Science and Technology Project-Engineering program of University and Institute Talents Servicing Enterprise (2017085CG/RC048(XBDX006)), and the Natural Science Foundation of Shaanxi Province (No. 2017JM2025).
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Conflict of interest
The authors declare that they have no conflict of interest.
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