掺杂Ni、Mn和Cu对磷酸铁锂电化学性能的影响  

Effect of Ni,Mn and Cu Doping on the Electrochemical Performances of LiFePO_4

作　　者：王圣平[1,2] 董康[1] 周权[1] 周成冈[1,2] 吴金平[1,2] 

机构地区：[1]中国地质大学(武汉)材料科学与化学工程学院,武汉430074 [2]中国地质大学(武汉)可持续能源实验室,武汉430074

出　　处：《硅酸盐学报》2011年第8期1275-1280,共6页Journal of The Chinese Ceramic Society

基　　金：湖北省自然科学基金(2010CDA017)资助项目

摘　　要：采用水热法合成了分别用Ni、Mn和Cu取代LiFePO4晶格中部分Fe位的掺杂LiMxFe1–xPO4(M=Ni、Mn、Cu;x=0.075、0.100、0.125、0.150、0.175)。对样品的物相结构和电化学性能进行了表征及测试,结果表明:制备的LiMxFe1–xPO4均为LiFePO4的基本结构,空间群为Pnma;掺杂增强了LiMxFe1–xPO4的导电能力、降低了Li+迁移阻抗,并显著提高了其电化学性能;LiMxFe1–xPO4中M的最佳掺杂量是x=0.125,其中LiNi0.125Fe0.875PO4的电化学性能最佳,具有较低的Li+嵌入/脱出反应阻抗(682.4?)、较高的比容量(首次达到127.8 mA?h.g–1)和较好的循环寿命(50次衰减率为13.2%)。The LiMxFe1–xPO4（M = Ni,Mn,Cu;x = 0.075,0.100,0.125,0.150,0.175） materials,which were doped by using Ni,Mn and Cu to replace the Fe site in the lattice of LiFePO4,respectively,were synthesized via a hydrothermal method.The phase structure,and electrochemical performance of the synthesized samples were characterized.The results indicate that the synthesized LiMxFe1–xPO4 samples have a crystal structure of LiFePO4 and a space group Pnma.The doping could increase the conductivity of the LiMxFe1–xPO4,decrease the Li＋ diffusion resistance,and dramatically increase the electrochemical performance of the LiMxFe1–xPO4.The optimal doping amount in a mole ratio of M（M = Ni,Mn,Cu） to Fe was 0.125：0.875.The LiNi0.125Fe0.875PO4 sample exhibited the superior electrochemical performance,which had a low charge transfer resistance（682.4 Ω）,a high specific capacity（127.8 mA·h·g^-1 in the initial cycle） and a better cycle life（the capacity fading rate was 13.2% after 50 cycles）.

关 键 词：磷酸铁锂 离子掺杂 电化学性能 

分 类 号：TM912.9[电气工程—电力电子与电力传动]