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采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、电池性能测试系统研究了多元稀土掺杂锂锰氧正极材料的相结构、形貌,并对其活化性能、循环稳定性能进行了表征。结果表明:采用Pechini法合成多元稀土掺杂LiMn2O4样品时,只有将掺杂元素的含量严格控制在一定范围内,所合成的LiMn2O4、LiLa0.03Mn1.97O4、LiLa0.012Ce0.012Mn1.976O4、LiLa0.012Nd0.012Mn1.976O4、LiCe0.012Nd0.012Mn1.976O4样品才具有纯尖晶石型LiMn2O4结构。当稀土掺杂元素含量较高时,所合成的LiLa0.015Ce0.015Mn1.97O4、LiLa0.015Nd0.015Mn1.97O4、LiCe0.015Nd0.015Mn1.97O4样品由LiMn2O4相及微量杂质相CeO2、Nd2O3、CeO2+Nd2O3组成。所有样品呈规则的近球形或球形,其粒径范围为0.5～2.8μm。适量的稀土元素掺杂将使LiMn2O4材料的初始容量减小、充放电效率及循环稳定性能增加,LiCe0.012Nd0.012Mn1.976O4样品具有较好的综合电化学性能,其初始容量为123.5mAh/g,经30次循环充放电后的容量为113.2mAh/g,为相同条件下LiMn2O4样品放电容量的1.27倍。
The phase structure and morphology of the multi-rare earth doped lithium manganese oxide cathode material were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and cell performance testing system. The properties of activation and cycling stability were characterized . The results show that LiMa2O4, LiLa0.03Mn1.97O4, LiLa0.012Ce0.012Mn1.976O4 and LiLa0 are synthesized only when the content of doping elements is controlled within a certain range by the Pechini method. 012Nd0.012Mn1.976O4, LiCe0.012Nd0.012Mn1.976O4 samples have a pure spinel LiMn2O4 structure. When the content of rare earth doping elements is high, the synthesized samples LiLa0.015Ce0.015Mn1.97O4, LiLa0.015Nd0.015Mn1.97O4 and LiCe0.015Nd0.015Mn1.97O4 are composed of LiMn2O4 phase and trace impurity phases CeO2, Nd2O3, CeO2 + Nd2O3 composition. All samples showed a regular near spherical or spherical shape with particle sizes ranging from 0.5 to 2.8 μm. Appropriate amount of rare earth elements doping LiMn2O4 material will reduce the initial capacity, charge-discharge efficiency and cycle stability increases, LiCe0.0Nd0.012Mn1.976O4 sample has good electrochemical properties, the initial capacity of 123.5mAh / g , After 30 cycles of charge and discharge capacity of 113.2mAh / g, under the same conditions LiMn2O4 sample discharge capacity of 1.27 times.