锂离子电池正极材料LiNi0.5Co0.2Mn0.3O2的制备与性能研究

Synthesis and Studies of LiNi0.5Co0.2Mn0.3O2 Cathode Material for Lithium-ion Batteries

以Ni（0.5）Co（0.2）Mn（0.3）（OH）2前驱体和Li2CO3为原料,在空气气氛下采用适当的烧结工艺制备了LiNi（0.5）Co（0.2）Mn（0.3）O2锂离子电池正极材料。采用振实密度仪、SEM和XRD等方法对材料烧结前后的密度、形貌与结构进行表征,并对烧结后的锂离子电池正极材料的电化学性能进行测试。结果表明烧结制备的LiNi（0.5）Co（0.2）Mn（0.3）O2正极材料混排因子c/a为4.9421,阳离子混排程度低I（003）/I（104）为2.222,层状结构明显。在2.8~4.3 V、0.2 C和0.5 C下,LiNi（0.5）Co（0.2）Mn（0.3）O2正极材料的首次放电比容量为153.6 m Ah·g^（-1）和146.5 mAh·g^（-1）,首次充放电效率分别为81.2%和78.8%,循环80次后容量分别保持为130.2 mAh·g^（-1）和128.1 mAh·g^（-1）,容量保持率都在85%以上,具有良好的电化学性能。

The LiNi0.5Co0.2Mn0.3O2 cathode material for Li-ion batteries were synthesized by sintering process with the precursor Ni0.5Co0.2Mn0.3（OH）2 and Li2CO3 as raw materials in air. The tap-density, morphology and crystal structure were evaluated by tap-density meter, Scanning Electron Microscopy（SEM） and X-Ray Diffraction（XRD） before and after sintering precursor Ni0.5Co0.2Mn0.3（OH）2, the electrochemical properties of LiNi0.5Co0.2Mn0.3O2 cathode material were tested by capacity cycling. The results showed that a hexagonal type structure with cation mixing factor of c/a is 4.9421, it means low cation mixing, the ratio of Characteristic peaks I（003） and I（104） is 2.222, with the obvious layered structure. The initial discharge capacity of LiNi0.5Co02Mn0.3O2 are 153.6 and 146.5 mAh,g^-1 in the voltage range of 2.8 - 4.3V at 0.2C and 0.5C with the first charge-discharge efficiency 81.2% and 78.8%, what＇ s important, it shows a reversible capacity of 130.2 and 128.1 mAh. g^-1 after 80 cycles, the capacity retention rate remains over 85 percent, it shows a good electrochemical performance.