The Capturing of Ionized Oxygen in Sodium Vanadium Oxide Nanorods Cathodes under Operando Conditions

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• 作者：Mengyu Yan ; Luzi Zhao ; Kangning Zhao ; Qiulong Wei ; Qinyou An ; Guobin Zhang ; Xiujuan Wei ; Wenhao Ren and Liqiang Mai
• 刊名：Advanced Functional Materials
• 出版年：2016
• 出版时间：September 26, 2016
• 年：2016
• 卷：26
• 期：36
• 页码：6555-6562
• 全文大小：2600K
• ISSN：1616-3028

文摘

The control of voltage window has been considered as a universal strategy in improving the cycling stability of cathode materials, which is supposed and explained by avoiding side reactions. To address the conjecture, the detailed structure evolution of Na_0.76V₆O₁₅ nanorods is investigated with different electrochemical reaction voltage windows. High time resolution in situ X-ray diffraction, ex situ X-ray photoelectron spectroscopy, ex situ Raman spectroscopy, and transmission electron microscopy demonstrate the amorphization of Na_0.76V₆O₁₅ nanorods and formation of ionized oxygen in nanorods, leading to the increased polarization voltage and fast capacity fading. The amorphization and diffusion of ionized oxygen in nanorods is controlled by optimizing the voltage window, resulting in the great increase of capacity retention from 26% to 80%. It is demonstrated that controlling the voltage window and corresponding ionized oxygen diffusion can mitigate the fast capacity fading to achieve long lasting lithium ion batteries.