| Lithium intercalation mechanism for β-SnSb in Sn-Sb thin films |
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| 作者姓名： | Qiang Ru Qin Tian She-jun Hu Ling-zhi Zhao |
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| 作者单位： | Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou, 510006, China |
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| 摘 要： | Based on the first-principles plane wave pseudo-potential method, the electronic structure and electrochemical performance of LixSn4Sb4 (x=2, 4, 6, and 8) and LixSn1-xSb4 (x=9, 10, 11, and 12) phases were calculated. A Sn-Sb thin film on a Cu foil was also prepared by radio frequency magnetron sputtering. The surface morphology, composition, and lithium intercalation/extraction behavior of the fabricated film were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and cyclic voltammetry (CV). Lithium atoms can easily insert into and extract out of the β-SnSb cell due to the low lithium intercalation formation energy. It is found that lithium atoms first occupy the interstitial sites, and then Sn atoms at the lattice positions are replaced by excessive lithium. The dissociative Sn atoms continue to produce different Li-Sn phases, which will affect the electrode stability and lead to the undesirable effect due to their large volume expansion ratio. The calculated lithium intercalation potential is stable at about 0.7 V, which is consistent with the experimental result.
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| 关 键 词： | lithium batteries first-principles Sn-Sb alloys electronic structure thin films |
| 收稿时间： | 9 February 2011 |
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