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无机材料学报

无机材料学报

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锂离子电池复合正极材料xLiFePO4·yLi3V2(PO4)3的制备与性能研究

郑俊超， 李新海， 王志兴， 覃东棉 ， 郭华军， 彭文杰   

  1. 中南大学 冶金科学与工程学院，长沙 410083
  • 收稿日期:2008-04-03 修回日期:2008-05-14 出版日期:2009-01-20 网络出版日期:2009-01-20

Synthesis and Characterization of Composite Cathode Material xLiFePO4·yLi3V2(PO4)3

ZHENG Jun-Chao， LI Xin-Hai， WANG Zhi-Xing， QIN Dong-Mian， GUO Hua-Jun， PENG Wen-Jie   

  1. School of Metallurgical Science and Engineering，Central South University, Changsha 410083， China
  • Received:2008-04-03 Revised:2008-05-14 Published:2009-01-20 Online:2009-01-20

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被引次数

1

摘要： 以FePO4·xH2O、V2O5、NH4H2PO
和Li2CO3为原料，以乙二酸为还原剂，在常温常压下经机械活化并还原嵌锂，形成无定形的5LiFePO4·Li3V2(PO4)3前驱体混合物，然后低温热处理合成出晶态的复合正极材料5LiFePO4·Li3V2(PO4)3.分别研究了复合材料的物相结构、形貌、电化学性能.SEM图像表明合成的材料粒径小、分布均匀，一次粒径为100～200nm.充放电测试结果表明，650℃烧结12h制得的复合正极材料5LiFePO4·Li3V2(PO4)3电化学性能优良，1C放电比容量高达158mAh/g，达到该复合材料的理论比容量（156.8mAh/g）.复合材料具有良好的倍率性能和循环性能，在10C放电比容量高达114mAh/g，100次循环后容量几乎无衰减.循环伏安测试表明，复合材料的脱嵌锂性能优良，且明显优于单一的LiFePO4和Li3V2(PO4)3.

关键词: 复合正极材料, 5LiFePO4·Li3V2(PO4)3, 电化学性能

Abstract: 5LiFePO4·Li3V2(PO4)3 was synthesized via calcining amorphous 5LiFePO4·Li3V2(PO4)3 obtained through lithiation of FePO4·xH2O and V2O5 by using oxalic acid as a novel reducing agent at room temperature. The crystal structure, morphology and electrochemical properties of the products were investigated. The results show that the sample synthesized at 650℃ for 12h has fine particle sizes of 100-200nm with homogenous sizes distribution. Electrochemical measurement results indicate that the material exhibites high rate characteristic and high discharge capacity of 158mAh/g (theoretic capacity 156.8mAh/g) and 114mAh/g at 1C and 10C rate, respectively. There is no obvious capacity fade observed after 100 cycles at 10C rate. The electrochemical performance of composite cathode material 5LiFePO4·Li3V2(PO4)3 is better than that of individual cathode material, such as LiFePO4 and Li3V2(PO4)3.

Key words: lithium ion battery, composite cathode material, 5LiFePO4·Li3V2(PO4)3, electrochemical performance

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