高电压正极材料LiNi_(0.5)Mn_(1.5)O_4的制备及电化学性能

Synthesis of High Voltage LiNi_(0.5)Mn_(1.5)O_4 as Cathode of Lithium Ion Batteries and Its Electrochemical Performances

以可溶性的金属离子盐为原料,以(NH4)2CO3为沉淀剂,采用沉淀法制备正极材料LiNi0.5Mn1.5O4,讨论了煅烧制度对材料性能的影响。采用X射线衍射、扫描电子显微镜和室温条件下充放电测试,对最终产物的物相、形貌和电化学性能进行了表征。结果表明:在750、850、950℃均得到了纯相的LiNi0.5Mn1.5O4材料;在850℃制备的LiNi0.5Mn1.5O4具有最好的电化学性能,在0.1、0.5、1.0、5.0C充放电倍率下容量分别为126.1、125.0、120.0、105.0 mA h/g,以0.5 C的倍率循环100次后,容量仍有119.0 mA h/g,与初始容量相比,保持率达到94%。

LiNi0.5Mn1.5O4, as cathode material of lithium ion batteries, was prepared with LiNO3, Ni（NO3）2·6H2O, Mn（NO3）2 and （NH4）2CO3 as precursors by an one-step co-precipitation method. The effect of synthesis temperature （i.e., 750, 850, 950℃） on the performance of LiNi0.sMnl.504 was investigated. The morphology and microstructure of the products were characterized by X-ray diffraction and scanning electron microscopy, respectively. The results by the charge and discharge tests at room temperature showed that as an electrode material for rechargeable lithium ion batteries, the LiNi0.5Mn1.5O4 sample prepared at 850 ℃ exhibited an optimum electrochemical performance among the three samples. The initial discharge capacity of the sample reached 126.1,125.0, 120.0, 105.0 mA.h/g at the rate of 0.1 C, 0.5 C, 1.0 C, 5.0 C, respectively. In addition, the sample exhibited a superior cycle performance. After 100 cycles it could retain 94% of its initial discharge capacity at the rate of 0.5 C.