High-rate capability of Li₃V₂(PO₄)₃/C composites prepared via a polyvinylpyrrolidone-assisted sol-gel method

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• 作者：Hao Wang^a ; Yajuan Li^a ; ^{yajuanli@csu.edu.cn} ; Chenghuan Huang^b ; Yuedan Zhong^a ; Suqin Liu^a
• 关键词：Lithium vanadium phosphate ; Carbon coating ; Polyvinylpyrrolidone ; High-rate capability ; Lithium-ion batteries
• 刊名：Journal of Power Sources
• 出版年：2012
• 期刊代码：58_03787753
• 类别：ce
• 出版时间：15 June, 2012
• 卷：208
• 期：Complete
• 页码：282-287
• 文件大小：767 K

摘要

Carbon-coated monoclinic Li₃V₂(PO₄)₃ (LVP/C) cathode materials are successfully prepared via a polyvinylpyrrolidone (PVP)-assisted sol-gel method. LVP/C composites are investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and electrochemical methods. The results indicate that the sample synthesized with 9 wt%PVP is coated with a carbon layer in a thickness of about 12 nm, which presents excellent rate capability and good cyclic performance. In the potential range of 3.0-4.3 V, it shows a capacity of 127.2 and 115.1 mAh g^鈭? at 1 and 10 C, respectively. Even at discharge rate of 20 C, it still has 81.8 mAh g^鈭? with 10.7%capacity loss after 120 cycles. The lithium diffusion coefficient of the as-prepared material is in the order of 10^鈭? cm² s^鈭?. Our experiment results demonstrate that the LVP/C composites prepared via a PVP-assisted sol-gel method can be an attractive candidate as cathode materials in high-power lithium-ion batteries.