作　　者： ; ; ; ; ; ;

机构地区： 西安建筑科技大学材料科学与工程学院

出　　处： 《功能材料》 2006年第12期1942-1945,共4页

摘　　要： 为提高LiFePO4的充放电性能,用化学沉淀法制备了镁离子掺杂的磷酸铁锂,用电化学方法测量了Li1-xMgxFePO4(x=0.00、0.02、0.05、0.07、0.10和0.20,摩尔分数)的充放电性能,用X射线衍射(XRD)和里特沃尔特(Rietveld)方法表征了掺杂对LiFePO4的晶体结构的影响。结果表明少量镁离子掺杂能有效地提高LiFePO4的比容量和循环性能,其中Li0.95Mg0.05FePO4具有更好的电化学性能,放电比容量高出LiFePO4约20mAh/g,镁离子掺杂提高了LiFePO4中Fe3+/Fe2+共存态的浓度,使材料具有更好的导电能力。 In order to improve the performance of LiFePO4, Li1-x MgxFePO4 was prepared by co-precipitation method, where x,the tool fraction of Mg^2＋ , is 0.00, 0.02, 0.05, 0.07, 0.10 and 0.20. Crystal structure and charge/discharge performance of doped LiFePO4 were investigated by X-ray diffraction with the Rietveld method and electrochemical measurement, respectively, The results show that Mg^2＋ doping with low concentration can increase the capacity and cycle performances of LiFePO4 ,and Li0.95 Mg0.05 FePO4 has better performance than the others, which discharge capacity is higher 20mAh/g than LiFePO4. Rietveld refinement indicates that doped metal atoms randomly substitute for Li atom in the LiFePO4 structure, Because Mg^2＋ doping not only causes the change of atomic position and distance and the shrinkage of crystal cell, but also increases the concentration of coexisted Fe^3＋/Fe^2＋ in LiFePO4, which increases the electrical conductivity of LiFePO4.

关 键 词： 锂离子电池 正极材料 镁掺杂

领　　域： [电气工程]