Reversible Lithium Storage at Highly Populated Vacant Sites in an Amorphous Vanadium Pentoxide Electrode

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• 作者：Oh B. Chae ; Jisun Kim ; Inchul Park ; Hyejeong Jeong ; Jun H. Ku ; Ji Heon Ryu ; Kisuk Kang ; Seung M. Oh
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：October 28, 2014
• 年：2014
• 卷：26
• 期：20
• 页码：5874-5881
• 全文大小：601K
• ISSN：1520-5002

文摘

A vanadium pentoxide electrode is prepared in the amorphous form (a-V₂O₅), and its electrode performances are compared to those for its crystalline counterpart (c-V₂O₅). The a-V₂O₅ electrode outperforms c-V₂O₅ in several ways. First, it is free from irreversible phase transitions and Li trapping, which evolve in c-V₂O₅, probably due to the lack of interactions between the inserted Li⁺ ions/electrons and V₂O₅ matrix. Second, the absence of Li trapping allows a reversible capacity amounting to >600 mA h g^鈥?, which is larger than that given by c-V₂O₅. Third, it shows an excellent rate property. The notably high reversible capacity and rate capability seem to be due to Li storage at vacant sites that are ill-defined but numerous in a-V₂O₅, which Li⁺ ions can easily access. However, irreversible capacity of a-V₂O₅ is appreciable in the first cycle due to a parasitic Li reaction with surface hydroxyl groups. Treatment with n-butyllithium can suppress the irreversible capacity by removing the surface hydroxyl groups.