碳包埋固相法制备LiFePO_4及其电化学性能研究  

Synthesis of LiFePO_4 by Solid-State Method with Raw Materials Embedded in Graphite and Electrochemical Properties

作　　者：康晓雪[1] 田彦文[1] 曲涛[2] 

机构地区：[1]东北大学材料与冶金学院,辽宁沈阳110004 [2]辽宁科技学院冶金系,辽宁本溪117000

出　　处：《东北大学学报（自然科学版）》2010年第6期860-863,共4页Journal of Northeastern University(Natural Science)

基　　金：辽宁省科技攻关项目(2005224016)

摘　　要：用石墨粉包埋取代保护性气氛,一步固相法制备LiFePO4.采用XRD,FTIR,SEM和恒电流充放电等方法对材料结构、形貌和电化学性能进行了表征.利用循环伏安法研究了Li+在LiFePO4中的嵌/脱过程.结果表明,这种改进的固相法可以合成亚微米级纯相橄榄石结构LiFePO4,所得材料具有良好的倍率性能和循环稳定性,在0.1C和1C倍率首次放电比容量分别为148.3和131.9mAh.g-1,1C和5C倍率下循环50次容量保持率分别为96%和90%.由循环伏安法计算得到阳极峰和阴极峰处Li+的表观扩散系数分别为1.64×10-13和1.94×10-13cm2.s-1.LiFePO4 was successfully synthesized as a product via one-step solid-state reaction during which the raw materials were embedded in graphite powder instead of the protective atmosphere when heated at high-temperature.The structure,morphology and electrochemical properties of the product were investigated by XRD,FTIR,SEM and galvanostatic charge/discharge test.The process of lithiation/delithiation of Li＋ in LiFePO4 electrode was studied by cyclic voltammetry.The results showed that the pure-phase olivine-type LiFePO4 composed of near spherical particles in sub-micrometered size can be obtained by this improved solid-state method.The LiFePO4 thus prepared has favorable multiplication rate and cycling stability.The initial discharge specific capacity is 148.3 and 131.9 mAh·g-1 if the rate is 0.1 C and 1 C,respectively;and after the charge/discharge action cycles 50 times the capacity holding rate is 96% and 90% if the rate is 1 C and 5 C,respectively.As calculated according to cyclic voltammetry,the apparent Li＋ diffusion coefficients are 1.64×10-13 and 1.94×10-13 cm2·s-1 at the peaks of corresponding CV curves of anode and cathode,respectively.

关 键 词：LIFEPO4 石墨包埋 一步固相法 扩散系数 循环伏安 

分 类 号：TM912.9[电气工程—电力电子与电力传动]