高等学校化学学报

高等学校化学学报 ›› 2012, Vol. 33 ›› Issue (10): 2326.doi: 10.7503/cjcu20120011

• 物理化学 • 上一篇    下一篇

电池正极材料Li3V2(PO4)3/C的水热合成和性能

王焕峰1, 高严英1, 姜倩倩2, 马聪1, 王兴尧1   

  1. 1. 天津大学理学院化学系, 天津 300072;
    2. 天津大学化工学院, 天津 300072
  • 收稿日期:2012-01-04 出版日期:2012-10-10 发布日期:2012-09-12
  • 通讯作者: 王兴尧, 男, 博士, 副教授, 主要从事功能材料的制备与性能研究. E-mail: wxyghw@tju.edu.cn E-mail:wxyghw@tju.edu.cn

Hydrothermal Synthesis and Electrochemical Characteristics of Cathode Materials Li3V2(PO4)3/C

WANG Huan-Feng1, GAO Yan-Ying1, JIANG Qian-Qian2, MA Cong1, WANG Xing-Yao1   

  1. 1. Department of Chemistry, College of Science, Tianjin University, Tianjin 300072, China;
    2. School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
  • Received:2012-01-04 Online:2012-10-10 Published:2012-09-12
  • Contact: WANG Xing-Yao E-mail:wxyghw@tju.edu.cn

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摘要：

以LiOH·H2O, NH4VO3, NH4H2PO4 和麦芽糖等为原料, 采用水热法合成了碳包覆的磷酸钒锂化合物, 考察了碳含量对材料电化学性能的影响. 利用XRD, TEM, SEM和恒流充放电测试等手段对产物的结构、 形貌和电化学性能进行表征. 结果表明, 在650℃煅烧的样品为单一纯相的单斜晶体结构. 晶体颗粒分布为100~300 nm, 粒度分散均匀, 分散性良好, 无团聚现象, 且在颗粒表面包覆了一层无定形碳, 这有利于改善材料的导电率. 含碳量为10.23%的样品, 在倍率1.0C的电流密度下, 在3.0~4.3 V电压范围内, 样品的首次放电比容量高达118.8 mA·h/g, 循环15圈后放电比容量为115.1 mA·h/g, 容量保持率为96.88%.

关键词: 磷酸钒锂, 正极材料, 水热法, 电化学性能

Abstract:

A novel hydrothermal method was used to synthesize carbon-coated lithium vanadium phosphate compound. LiOH·H2O, NH4VO3, NH4H2PO4 and maltose without further purification were selected as starting materials to prepare precursor and the Li3V2(PO4)3/C which was obtained by sintering precursor at 650℃ for 2 h in flowing argon, and the effects of carbon content on electrochemical properties were investigated. The structural, morphology and electrochemical properties were investigated via X-ray diffraction(XRD), transmission electron microscopy(TEM), scanning electron microscopy(SEM) and constant current charge-discharge cycling. The compound synthesized at 650℃ took on pure monoclinic crystal structure, the particle size of the samples were ranged from 100 nm to 300 nm and there was a layer of carbon on the surface of Li3V2(PO4)3/C particles, which was available for enhancing the conductivity of Li3V2(PO4)3. Electrochemical properties of Li3V2(PO4)3/C were investigated. The results show that the Li3V2(PO4)3/C synthesized at 650℃ exhibits the highest initial discharge capacity of 118.8 mA·h/g and at the 15th cycle, the sample still keeps 115.1 mA·h/g at 1.0C in the voltage range of 3.0-4.3 V with 10.23% carbon contents. This behavior indicates that the Li3V2(PO4)3/C material obtained by hydrothermal method has excellent capacity retention and rate capability.

Key words: Li3V2(PO4)3/C, Cathode material, Hydrothermal method, Electrochemical property

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