镁离子掺杂对LiFePO_4/C电化学性能和结构的影响  

Effects of Mg Ion Doping on the Electrochemical Performances and Structure of LiFePO_4/C

作　　者：杨书廷[1] 刘玉霞[1] 尹艳红[1] 王辉[1] 崔成伟 

机构地区：[1]河南师范大学化学与环境科学学院,新乡453007 [2]河南省新能源材料工程研究中心

出　　处：《无机材料学报》2007年第4期627-630,共4页Journal of Inorganic Materials

基　　金：河南省重大科技攻关项目(0522020300)

摘　　要：以乳酸镁做为Mg^(2+)的掺杂源和部分的碳源,在惰性氛围下用模板-固相合成法合成了掺Mg^(2+)的LiFePO_4/C复合正极材料,考察了Mg^(2+)对于目标化合物电化学和物理性能的影响.研究结果表明,在C/3倍率下材料掺杂前后第二个循环的放电容量分别为140.5和159.9mAh/g,循环20次后容量为140.4和162.1mAh/g.电化学交流阻抗表明,掺杂后的材料阻抗R_(ct)从180Ω减小到120Ω.掺杂后振实密度比掺杂前提高了0.229g·cm^(-3).Stoichiometric Mg-doped LiFePO4/C cathode material was synthesized through a templatesolid state reaction in an inert atmosphere using magnesium lactate as dopant and part of carbon source. Effects of Mg2＋ doping on the electrochemical and physical performances of the cathode materials were investigated. At 1/3C discharge rate, the secondly reversible specific capacity of the Mg-doped LiFePO4/C is nearly 20mAh/g higher than that of the undoped one. After 20 cycles, the capacity of the former is 162.1mAh/g, 22mAh/g higher than that of the latter. Impedance Rct of the Mg-doped material is 120Ω, while that of the undoped material is 180Ω.The tap density of Mg-doped material is also improved by 0.229g.cm^-3 compared with undoped material.

关 键 词：乳酸镁 LIFEPO4/C 正极材料 掺杂 

分 类 号：TM912[电气工程—电力电子与电力传动]