摘要
以FePO4·xH2O、V2O5、NH4H2PO4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.
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 investiga- ted. 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 1 C 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 Li3 V2 （ PO4 ） 3.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第1期143-146,共4页
Journal of Inorganic Materials
基金
国家重点基础研究发展计划(2007CB613607)
