改进Sol-gel法合成LiFePO4正极材料及其电化学性能
A Modified Sol-gel Synthesis of LiFePO4 Cathodic Materials and Its Electrochemical Properties
作者：徐峙晖(四川大学 化学学院,四川 成都610064)；徐亮(四川大学 化学学院,四川 成都610064)；赖琼钰(四川大学 化学学院,四川 成都610064)
Author：(School of Chemistry,Sichuan Univ.,Chengdu 610064,China)；(School of Chemistry,Sichuan Univ.,Chengdu 610064,China)；(School of Chemistry,Sichuan Univ.,Chengdu 610064,China)
收稿日期：2006-03-06 年卷（期）页码：2006,38(5):112-116
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：磷酸锂铁；sol-gel；正极材料；电化学性能
Key words：lithium iron phosphate;sol-gel;cathodic materials;electrochemical performance
基金项目：教育部博士点基金资助项目（20020610027）
中文摘要
为了获得颗粒均匀、细小和电化学性能优异的LiFePO4, 采用sol-gel方法并添加表面活性剂聚乙二醇(PEG)制备LiFePO4/C。制备样品分别用XRD和SEM进行表征，通过充放电和循环伏安测试电化学性能。结果表明，nPEG/nLFP=1∶1、600 ℃制得样品颗粒均匀，平均粒径约为100 nm，在2.0～4.0 V(vs. Li)范围内,15 mA/g电流密度下放电，首次放电比容量为158 mAh/g，是理论容量的92.9％。制备样品展现良好的倍率性能和循环性能。
英文摘要
In order to obtain fine-paiticle LiFePO4 with excellent electrochemical performance, LiFePO4/C powders were synthesized by a poly(ethylene glycol)(PEG) assisted sol-gel method. The prepared samples were characterized by X-ray powder diffraction and scanning electron microscopy, and its electrochemical properties were investigated by charge-discharge tests and cycle voltammograms. The results showed that the sample, synthesized with the nPEG/nLFP=1∶1 and under sintering temperature of 600 ℃, has the uniform particle size of about 100 nm, and deliveres the first discharge capacity of 158 mAh/g at the 15 mA/g rate between 2.0 and 4.0 V(vs. Li), i.e. 92.9% of the theoretical capacity. The sample also displayed a good rate capability and stable cycle-life. The improved electrochemical performance originated mainly from the fine particle of nanometric dimension and the uniform size distribution in the product as well as the increase in electronic conductivity by the carbon coating.
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