CSTR系统制备高性能Ni0.6Co0.2Mn0.2(OH)2及电化学性能研究

Synthesization and electrochemical properties of Ni0.6Co0.2Mn0.2(OH)2 ternary cathodes for lithium batteries in the system of CSTR

摘要:

采用共沉淀法在CSTR(连续搅拌反应器系统)工艺体系中批量合成出镍钴锰三元氢氧化物前驱体Ni0.6Co0.2Mn0.2(OH)2 (622)，掺入适量的Li2CO3高温焙烧后得到锂离子二次电池正极材料Li[Ni0.6Co0.2Mn0.2]O2。使用扫描电子显微镜(SEM)观察样品形貌，X射线衍射仪(XRD)及透射电子显微镜(TEM)分析合成样品的具体结构，充放电循环测试系统测试其电化学性能。SEM测试表明产物为二次粒子团聚而成类球形颗粒；XRD及TEM结果表明合成的样品具有典型的层状α-NaFeO2结构。在电压范围为2.8 V-4.3 V，0.2 C倍率条件下，首次充放电容量分别为206 mAh g-1 和176 mAh g-1，100次循环后容量保持率达到85%。

关键词:锂离子电池;正极材料;CSTR;共沉淀法

Abstract:

Ni0.6Co0.2Mn0.2(OH)2 as precursor of lithium-ion batteries ternary cathode material was prepared for batch preparation by a hydroxyl co-precipitation method in the system of CSTR (continuous stirred tank reactor). Then, the Ni0.6Co0.2Mn0.2(OH)2 was roasted with Li2CO3 to receive Li[Ni0.6Co0.2Mn0.2]O2 under high temperature in the air. Scanning electron microscope (SEM), X-ray diffraction (XRD) and Transmission electron microscope (TEM) were used to examine the morphology and structure of the obtained Li[Ni0.6Co0.2Mn0.2]O2. The resulting Li[Ni0.6Co0.2Mn0.2]O2 powders have a type of spherical structure composed of secondary particles with a typical α-NaFeO2 lamellar structure. The electrochemical tests indicate that this cathode material have a good electrochemical reversibility and much better cycling stability in the voltage range of 2.8 and 4.3 V. Its initial charge and discharge specific capacity are as high as 206 mAh g-1 and 176 mAh g-1 at 0.2 C, with a capacity retention rate of 85% after 100 cycles．

Key words:Lithium-ion battery; cathode material; electrochemical performace; co-precipitation