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随着电动汽车的发展,迫切需要具有高安全性、高能量密度、高功率、大容量、长寿命、高环保、低成本等优点的锂离子电池。层状结构的富锂锰基正极材料由于具有比容量高、平台电压高、热稳定性好、价格低廉的特点而被认为是有希望的未来电动汽车候选正极材料之一。尽管其拥有很高的比容量,但仍存在着首次循环不可逆容量高、倍率性能差等问题,纳米化是改进材料倍率性能的一种有效手段。本文以Ni O,Co_3O_4,Mn CO_3和Li_2CO_3为原料,成功制备得到了纳米级的锂离子电池正极材料Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_2。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和充放电测试对所得样品的结构、形貌及电化学性能进行了表征。结果表明,合成的Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_2材料具有层状结构,一次颗粒均匀、细小,平均颗粒尺寸约为90 nm,并具有良好的电化学性能,在2.0~4.8 V以0.1C充放电时,首次放电比容量达到284 m Ah·g~(-1),首次库伦效率为86.1%。材料同时拥有良好的倍率性能,1.0C放电容量达到240 m Ah·g~(-1),3.0C放电容量达到210 m Ah·g~(-1)。
With the development of electric vehicles, lithium ion batteries with high safety, high energy density, high power, large capacity, long life, high environmental friendliness and low cost are urgently needed. Layered Li-Mn-based cathode materials are considered as promising candidate for cathode materials for electric vehicles due to their high specific capacity, high plateau voltage, good thermal stability and low cost. Despite its high specific capacity, there are still problems of high first-order irreversible capacity and poor rate performance. Nanocrystallization is an effective way to improve material rate performance. Li (1.2) Ni 0.13 Co 0.13 Mn 0.54 O 2 was prepared successfully on the basis of NiO, Co 3 O 4, Mn CO 3 and Li 2 CO 3 as raw materials. The structure, morphology and electrochemical properties of the obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and charge-discharge test. The results show that the Li1.2Ni0.13Co0.13Mn0.54O2 material has a layered structure, the primary particles are uniform and fine, the average particle size is about 90 nm, and has good electrochemical performance. The initial discharge capacity reaches 284 m Ah · g -1 at 2.0 ~ 4.8 V at 0.1 C, and the first coulombic efficiency is 86.1%. The material also has a good rate performance, 1.0C discharge capacity of 240 m Ah · g -1, 3.0C discharge capacity of 210 m Ah · g -1.