Abstract:

The high nickel cathode materials are considered as key materials for upgrading energy density of current lithium-ion battery due to their high theoretical specific capacity (270mA·h/g). Currently, the ternary hydroxide precursors of high nickel materials are typically prepared using co-precipitation methods, which is significant in determining the performance of the final sintered material. During the co-precipitation process, factors such as ammonia content, pH value, reaction temperature, solid content, stirring rate and impurities jointly affect the physicochemical properties of the product, making it challenging to synthesize cathode materials with targeted performance. This work investigated the preparation process and basic properties of high nickel precursors with different particle size distributions and nickel contents of 88%, 90%, 92%, and 94% (molar ratios of Ni in Ni, Co, Mn). Furthermore, focusing on the precursor material with a nickel content of 94%, the effects of synthesis parameters, ammonia content, pH and stirring rate, on the properties of the precursor product were explored. It was found that under relatively low ammonia content, pH and stirring speed conditions, it was easier to prepare precursors with uniform particle size distribution and intact morphology. Moreover, the resulting high nickel materials exhibited higher discharge capacity and initial coulombic efficiency.

Key words: electrochemistry, preparation, high nickel material, cathode, lithium-ion battery, technology

摘要：

高镍三元正极材料因其高的充放电比容量（270mA·h/g），被认为是进一步提升锂离子电池能量密度的一种关键材料。高镍三元正极材料的前体通常采用共沉淀法制备，其性质对最终烧结得到的三元正极材料的性能有显著影响。在共沉淀反应制备前体的过程中，氨含量、pH、反应温度、固含量、搅拌速率、杂质等诸多因素共同影响着产物的物理化学性质，增加了合成特定指标三元正极材料的难度。本文探究了具有不同粒径分布，镍含量（镍在镍钴锰三元素中的摩尔分数）分别为88%、90%、92%、94%的高镍三元前体的制备工艺与基本性质。进一步地，选择镍摩尔分数为94%的前体材料，从氨含量、pH及搅拌速率三个方面探究了合成参数对前体产物的影响，发现在相对较低的氨含量、pH以及搅拌速率条件下，更容易制备得到粒径分布均匀、形貌完好的前体，并且得到的三元材料具有更高的放电容量以及首圈库仑效率。

关键词: 电化学, 制备, 高镍材料, 正极, 锂离子电池, 工艺