稀土掺杂锂电池正极锰酸锂的合成及电化学性能

Synthesis and Electrochemical Performance of Rare Earth-Doped Lithium Manganate as Cathode Materials for Rechargeable Lithium-ion Batteries

采用X-射线衍射仪（XRD）、扫描电子显微镜（SEM）、电池性能测试仪等系统分析了Pechini法合成的LiM。Mn2--xO4（M—La，Ce，Nd；x=0，0．02，0．03）的结构、形貌、首次充放电及循环稳定性等。结果表明：除LiCe0.03Mn1.97O4、LiNd0.03.Mn1.97O4样品含有微量杂质相（CeO2或Nd2O3）外，其他样品均具有纯的尖晶石型LiMn2O4结构；样品呈规则的球形或近球形，粒径为1．0～2．0μm；采用适量的稀土掺杂可显著提高LiMnz04样品的首次充放电和循环稳定性能，LiLao0.03Mn1.97O4样品的首次放电容量为123．3mAh／g，经30次循环充放电后的容量仍保持在112．8mAh／g，容量保持率为91．5％，远高于相同条件下未掺杂样品的容量保持率。

The structure,the microstructure,the activate and the cyclic properties of the lithium ion battery cathode materials LiMxMn2-xO4 （M = La, Ce, Nd ; x = 0,0. 02,0. 03） prepared by Pechini method were investigated by means of X-ray diffraction （XRD）,the scanning electron microscope （SEM） and the battery testing system. The results showed that the samples were composed of pure spinel LiMn204 phase except the existing trace CeO2 and Nd2O3 phases in the LiCe0. 03Mn1. 97O4 and LiNd0. 03Mnl. 97O4 specimens, respectively. The particles of the samples were spheroid or sphere ,and the diameter of the particles was 1.0-2.0μm. The activation and cyclic stability of the specimen would increase markedly with the manganese partial replaced by the rare earth elements. The initial discharge-capacity of the LiLa0.03Mnl.97P4 sample was 123. 3 mAh/g,and after 30th cycles,the capacity decrease to 112.8 mAh/g 91.5% of the initial capacity,which was much higher than that of the LiMn2O4 sample.