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电化学(中英文) ›› 2013, Vol. 19 ›› Issue (6): 565-570.  doi: 10.13208/j.electrochem.130356

• 锂离子电池近期研究专辑 (厦门大学 杨勇教授主编) • 上一篇    下一篇

钒替代对碳包覆硅酸铁锂复合材料结构的影响(英文)

杨洪1,张颖1,2,程璇1,2*   

  1. 1. 厦门大学材料学院,材料科学与工程系,厦门 361005;2. 福建省特种先进材料重点实验室,厦门 361005
  • 收稿日期:2013-05-16 修回日期:2013-07-08 出版日期:2013-12-28 发布日期:2013-12-23
  • 通讯作者: 程璇 E-mail:xcheng@xmu.edu.cn
  • 基金资助:

    Supported by Fujian Key Laboratory of Advanced Materials, China (No. 2006L2003).

Effect of Vanadium Substitution on Structure of Li2FeSiO4/C Composites

YANG Hong1, ZHANG Ying1,2, CHENG Xuan1,2*   

  1. 1. Department of Materials Science & Engineering, College of Materials; 2. Fujian Key Laboratory of Advanced Materials, Xiamen University, Xiamen, Fujian 361005, P.R. China
  • Received:2013-05-16 Revised:2013-07-08 Published:2013-12-28 Online:2013-12-23
  • Contact: CHENG Xuan E-mail:xcheng@xmu.edu.cn
  • Supported by:

    Supported by Fujian Key Laboratory of Advanced Materials, China (No. 2006L2003).

摘要: 以廉价的硝酸铁为铁原料,通过溶胶凝胶和固相反应法制得碳包覆硅酸铁锂(Li2FeSiO4/C)正极材料,以偏钒酸铵(NH4VO3)为钒原料,按理论计算量5,10,15,20,25,30和50%制得钒替代Li2FeSiO4/C复合材料(Li2Fe1-xVxSiO4/C). 结果表明,Li2FeSiO4/C(主相P21/n)结晶良好,基本无杂相,而Li2Fe1-xVxSiO4/C(主相P21/n)存在主要杂质偏硅酸锂和钒/铁氧化物. Li2FeSiO4/C和Li2Fe0.95V0.5SiO4/C电极C/16(室温)的首次放电比容量分别达160.9 mAh·g-1和130.8 mAh·g-1. 钒替代量的增加,无定形碳的石墨化程度增强,碳包覆量却减少. 钒替代量直接影响钒/铁氧化物的形成量,导致Li2Fe0.95V0.5SiO4/C电极电化学性能较差.

关键词: 硅酸铁锂, 钒取代, 正极材料, 锂离子电池

Abstract: The carbon coated lithium iron silicate (Li2FeSiO4/C) composites were prepared using less expansive iron starting material of soluble ferric nitrate through sol-gel process and solid state reaction. The theoretically calculated amounts of 5, 10, 15, 20, 25, 30, and 50% of vanadium (V) were introduced using NH4VO3 to obtain V-substituted Li2FeSiO4/C composites. It was found that the pure Li2FeSiO4/C composite exhibited a good crystallinity with P21/n and nearly no impurities being detected, while the V-substituted Li2FeSiO4/C composites showed major impurities of Li2SiO3 and V3O4/Fe3O4. The discharge capacities of 160.9 mAh·g-1 and 130.8 mAh·g-1 at C/16 were obtained for the pure and 5% V-substituted Li2FeSiO4/C composites, respectively. The degree of graphitization in amorphous carbon was enhanced and the quantities of carbon coated were lowered with the increase of V-substituted amounts. The electrochemical performance of 5% V-substituted Li2FeSiO4/C composite was not improved due to the presences of impurities which were directly linked to the amounts of V substitution.

Key words: lithium iron silicates, vanadium substitution, cathode materials, lithium ion battery

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