Mn^(2＋)掺杂对LiFePO_4正极材料结构、性能及嵌锂动力学的影响  

Effects of Mn^(2+) doping on structure,performance and kinetic of lithium-ion insertion of LiFePO_4 positive-electrode material

作　　者：伊廷锋[1,2,3] 朱彦荣[1] 沈浩宇[2,3] 马永泉 左朋建[2] 诸荣孙[1] 

机构地区：[1]安徽工业大学化学与化工学院,安徽马鞍山243002 [2]哈尔滨工业大学化工学院,哈尔滨150001 [3]超威电源有限公司,浙江湖州313100

出　　处：《哈尔滨工业大学学报》2013年第7期121-125,共5页Journal of Harbin Institute of Technology

基　　金：国家自然科学基金资助项目(51274002,50902001);中国博士后科学基金资助项目(2012M520749);浙江省博士后科研择优资助项目(Bsh1201013);安徽工业大学“绿色能源材料化学基础研究与应用开发”创新团队资助项目(TD201202)

摘　　要：为了改善橄榄石型LiFePO4正极材料的性能,采用高温固相法合成了Mn掺杂的LiMnxFe1-xPO4(x=0,0.10,0.25,0.40,0.50)材料.采用X射线粉末衍射、扫描电子显微镜、充放电测试、循环伏安和电化学阻抗谱研究了材料的结构、电化学性能和锂离子嵌脱动力学.结果表明,锰掺杂的LiFePO4样品颗粒分布比较均匀,具有较小的平均粒径和窄的粒度分布,LiMnxFe1-xPO4是纯相的橄榄石结构.在不同倍率下,LiMn0.4Fe0.6PO4具有最高的放电容量和最好的动力学性能.Mn的掺杂提高了LiFePO4材料的可逆性、锂离子扩散系数和放电容量,减小了电荷转移电阻,进而提高了其动力学性能.To improve the performance of olivine LiFePO4 positive-electrode material, the Mn-doped LiMnxFel_xPO4 （x = 0, 0. 10, 0. 25, 0.40, 0.50） materials were prepared by a solid-state reaction method. The structure, electrochemical performance and lithium ion insertion-extraction kinetic of the material are investigated by scanning electron microscopy （SEM）, X-ray diffractometry （XRD）, charge-discharge tests, cyclic voltammetry （CV） and electrochemical impedance spectroscopy （EIS）. The results show that the Mn- doped LiFePO4 material powders have a uniform morphology, a small particle size and narrow particle size distribution, and LiMn^Fe1-xPO4 materials are pure phase olivine structure. LiMn0.4Fe0.rPO4 shows the highest discharge capacity and the best kinetic performance among all samples at different rates. The Mn doping improves the reversibility, Li ~ ions diffusion coefficient and discharge capacity, and reduces the charge transfer resistance, and then increase the kinetic performance of LiFePO4 material.

关 键 词：锂离子电池 正极材料 LiMnxFe1-xPO4 动力学性能 

分 类 号：TM912.9[电气工程—电力电子与电力传动]