锰含量对LiNi0.85-xCo0.15MnxO2结构及形貌的影响

采用共沉淀法先合成出氢氧化物前驱体Ni0.85-xCo0.15Mnx(OH)2,其中X=0、0.1、0.2和0.4,前驱体与Li2CO3在空气气氛中固相烧结制得正极材料LiNi0.85-xCo0.15MnxO2。用XRD、SEM研究了锰含量对材料结构和形貌的影响。研究发现,LiNi0.85Co0.15O2的X射线衍射图中存在微量第二相,而锰掺杂有利于减小反应过程中锂离子损失和镍离子占据锂位,容易形成有序层状结构材料。随着Mn离子替代Ni离子量的增加,晶胞参数a减小,晶胞参数c、c/a及I003/I104值增大。SEM结果表明前驱体和最终产物形貌均随锰含量增加颗粒均匀性增强,粒子尺寸变小,粒径分布变窄。

Effect of Mn Content on the Structure and Morphology of LiNi0.85-xCo0.15MnxO2 Cathode Materials

The metal hydroxide Ni0.85-xCo0.15Mnx(OH)2 precursors with x=0,0.1,0.2 and 0.4 were prepared by the co-precipitation method.LiNi0.85-xCo0.15MnxO2 cathode materials were synthesized by mixing Ni0.85-xCo0.15Mnx(OH)2 with Li2CO3 via the solid-state reaction followed by heating in air.The effect of Mn content on the structure and morphology of LiNi0.85-xCo0.15MnxO2 cathode materials were analyzed by XRD and SEM.Xray diffraction pattern of LiNi0.85Co0.15O2 exists in little impure phase.With the Mn-doped increases,lithium loss and departure from stoichiometry are decreased,so,single phase and ordered layered materials are formed easily.With the amount increase of Mn content substituted for Ni content,the lattice parameter a exhibits a shrunken trend,the lattice parameter c and the ratio of peak intensities of I003/I104 and c/a increase.SEM micrographs of the precursors and the final product reveal that increasing Mn content not only decreases the particle size,but also narrows the particle size distribution.