Carbon-Enhanced Electrochemical Performance for Spinel Li5Cr7Ti6O25 as a Lithium Host Material

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• 作者：Lei Yan ; Shangshu Qian ; Haoxiang Yu ; Peng Li ; Hua Lan ; Nengbing Long ; Ruifeng Zhang ; Miao Shui ; Jie Shu
• 刊名：ACS Sustainable Chemistry & Engineering
• 出版年：2017
• 出版时间：January 3, 2017
• 年：2017
• 卷：5
• 期：1
• 页码：957-964
• 全文大小：695K
• ISSN：2168-0485

文摘

The design and facile fabrication of CrTi-based anode materials with long-life, good safety, and low cost are strongly desired for lithium-ion batteries. In this study, we adopt the sol–gel method using glucose as carbon source to synthesize carbon-coated Li₅Cr₇Ti₆O₂₅. The effects of a carbon layer in Li₅Cr₇Ti₆O₂₅/C on electrochemical properties are focused through comparing carbon-coated Li₅Cr₇Ti₆O₂₅ with carbon-free Li₅Cr₇Ti₆O₂₅. Electrochemical tests show that Li₅Cr₇Ti₆O₂₅/C possesses better cycling and rate performances than those of carbon-free Li₅Cr₇Ti₆O₂₅. Cycled at 500 mA g^–1, Li₅Cr₇Ti₆O₂₅/C delivers a high specific capacity of 111.6 mAh g^–1 with 13% capacity loss after 200 cycles. In contrast, Li₅Cr₇Ti₆O₂₅ only exhibits a specific capacity of 93.6 mAh g^–1 at 500 mA g^–1 with 19% capacity loss after 200 cycles. The preeminent electrochemical property of Li₅Cr₇Ti₆O₂₅/C is ascribed to the amorphous carbon coating layer. This carbon layer can remarkably facilitate the transportation of electrons and ions in Li₅Cr₇Ti₆O₂₅. Furthermore, the lithiation/delithiation behavior of Li₅Cr₇Ti₆O₂₅/C is also investigated by advanced in situ X-ray diffraction technique, and the results verify that Li₅Cr₇Ti₆O₂₅/C possesses a highly reversible structural change during the charge/discharge process.