锂离子电池正极材料LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2的产业化工艺研究

Study on industrialization process of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2 cathode material for lithium ion batteries

通过共沉淀法在体积为200 L的密闭反应釜内采用连续工艺合成具有类球形形貌的层状前驱体Ni0.8Co0.1Mn0.1(OH)2,解决了间歇式生产工艺存在的效率低、批次稳定性差等问题。研究了合成过程中搅拌方式、反应温度、pH和络合剂用量对前驱体振实密度的影响,确定了最佳工艺条件。利用前驱体与Li OH·H2O通过高温固相反应合成LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2材料。用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对材料的晶体结构和形貌进行表征,通过充放电测试研究材料的电化学性能。通过XRD分析可知该材料为典型的六方晶系a-Na FeO_2结构;SEM测试发现产物粒子是由300~800 nm的一次小晶粒堆积形成的二次类球形粒子。电化学测试表明,在2.5~4.3 V电压范围内,在0.2 C倍率下首次放电容量和库仑效率分别为184.1 m Ah/g和85.9%,20次循环后容量为166.3 m Ah/g,保持率达到90.3%。

Spherical mixed metal hydroxide Ni0. 8 Co0. 1 Mn0. 1（OH）2 precursor with layered structure is successfully synthesized via continuous coprecipitation method in a 200 L closed reactor,which solves the problems of low efficiency and poor stability in batch production process. The effects of stirring method,temperature,pH and amount of chelating agent on the tap density of precursor are studied and the optimum synthesis conditions are confirmed.LiNi0.8Co0.1Mn0.1O2 sample is obtained by high temperature solid phase reaction between the precursors and Li OH·H2 O,and its crystal structure,morphology and electrochemical properties are investigated by means of X-ray diffraction（XRD）,scanning electron microscopy（SEM） and charge-discharge test.XRD analysis identifies that this sample has a typical structure of hexagonal a-Na FeO2 type.It is found through SEM detection that LiNi0.8Co0.1Mn0.1O2 consists of sphere-like secondary particles that are aggregated by a large amount of primary small particles with an average size of about 300-800 nm.Electrochemical measurements show the initial discharge capacity and the first coulombic efficiency of LiNi0.8Co0.1Mn0.1O2 at 0. 2 C rates are 184. 1 m Ah·g^（-1） and 85. 9% respectively in the voltage range of 2. 5-4. 3 V.After 20 cycles at 0. 2 C,the discharge capacity and the discharge capacity retention are 166. 3 m Ah·g^（-1） and 90. 3%,respectively.