无机材料学报 ›› 2015, Vol. 30 ›› Issue (2): 122-128.DOI: 10.15541/jim20140231

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聚乙二醇为碳源合成0.7LiFePO4ּ0.3Li3V2(PO4)3/C 复合正极材料及性能研究

马平平1, 2, 刘志坚1, 夏建华1, 卢志超1   

  1. (1. 中国钢研科技集团公司 安泰科技股份有限公司, 北京100081; 2. 北京中新联科技有限公司, 北京100041)
  • 收稿日期:2014-05-04 修回日期:2014-06-27 出版日期:2015-02-20 网络出版日期:2015-01-27
  • 基金资助:
    国家科学技术研究发展863计划(2008AA03Z208)

Electrochemical Performance of 0.7LiFePO4ּ0.3Li3V2(PO4)3/C Cathode Materials Using Polyethylene Glycol as Carbon Source

MA Ping-Ping1, 2, LIU Zhi-Jian1, XIA Jian-Hua1, LU Zhi-Chao1   

  1. (China Iron and Steel Research Institute Group Advanced Technology & Materials Co.Ltd. Technology Center, Beijing 100081, China; 2. Beijing Central Press Union Technology Co., LTD., Beijing 100041, China)
  • Received:2014-05-04 Revised:2014-06-27 Published:2015-02-20 Online:2015-01-27
  • Supported by:
    863 Program (2008AA03Z208)

摘要:

以LiOH·H2O、FeC2O4·2H2O、NH4VO3和NH4H2PO4为原料, 分别以不同聚合度的聚乙二醇(PEG-200、PEG-600、PEG-1000、PEG-2000、PEG-6000)为碳源, 通过高温固相法合成0.7LiFePO4·0.3Li3V2(PO4)3/C复合正极材料(LFVP/C)。用X射线衍射、拉曼光谱和扫描电镜对材料的结构和形貌进行了表征。充放电测试表明, 在电压范围为2.0~4.3 V 时, PEG-200为碳源的LFVP/C的复合正极材料具有较高的比容量、优良的循环性能和倍率特性。10C条件下其放电容量可以保持120 mAh/g。

关键词: 锂离子电池, LiFePO4, Li3V2(PO4)3, 聚乙二醇, 正极材料

Abstract:

Different molecular weight of polyethylene glycol (PEG), including PEG-200, PEG-600, PEG-1000, PEG-2000 and PEG-6000, were used as carbon sources and reduction agents for preparation of 0.7LiFePO4?0.3Li3V2(PO4)3/C composites via spay-drying followed solid-state reaction approach. The structure and morphology of the 0.7LiFePO4?0.3Li3V2(PO4)3/C composite samples were characterized by X-ray diffraction(XRD), Raman spectroscope and field-emission scanning electron microscope (FE-SEM). The diffraction peaks of the synthesized compound were composed of both orthorhombic LiFePO4 and monoclinic Li3V2(PO4)3, indicating the synthesized compound is a mixture phase of LiFePO4 and Li3V2(PO4)3. The structure of residual carbon was characterized by Raman spectroscope. A lower intensity ratio of the ID/IG band for PEG-200 in Raman spectrum indicated more graphite clusters in the structure of carbon, which would enhance the electronic conductivity of the residual carbon. The composites showed higher discharge capacity, better rate capability and cyclic performance. Even at a high charge-discharge rate of 10C, it still maintained a discharge capacity of 120 mAh/g in the potential range of 2.0-4.3 V.

Key words: Lithium-ion battery, LiFePO4, Li3V2(PO4)3, polyethylene glycol, cathode materials

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