Abstract: During the synthesis of precursor materials for ternary lithium battery cathodes via co-precipitation, the presence of impurities such as iron, aluminum, magnesium, copper, and sulfur can adversely affect the electrochemical performance of the final cathode materials. The existing studies are lack in mechanism analysis of the influence of coprecipitation conditions on the inclusion of impurities in precursor particles. The impurities in Ni0.8Co0.1Mn0.1(OH)2 synthesized via co-precipitation have been analyzed using multiple characterization methods. The impurities primarily consist of sodium, magnesium, calcium, iron, copper, zinc, aluminum, and sulfur, and may be distributed within the crystal lattice, interstitial sites, or on the surface of the precursor particles. The results indicate that the concentration of ammonia has a significant effect on the contents of iron, copper, zinc, and aluminum. The precursor synthesized under the condition of pH 11.7 is colloidal and has a larger specific surface area, which adsorbs the highest amounts of sodium and sulfur, being 28134.62 and 12898.50 μg/g, respectively. The variation in stirring speed has a certain effect on the distribution of sulfur content. Optimizing the process conditions of ternary precursor co-precipitation process is of great significance to control the impurity content in the precursor and improve the electrochemical performance and safety of the final ternary cathode material.

Key words: co-precipitation, Ni0.8Co0.1Mn0.1(OH)2, ammonia concentration, pH value, stirring speed, impurity types and contents

摘要： 在共沉淀法合成三元锂离子电池正极材料的前驱体过程中，铁、铝、镁、铜、硫等杂质的残留会对最终合成的正极材料的电化学性能产生不利影响。现有研究缺少关于共沉淀条件对前驱体颗粒中杂质掺入的影响规律与机理分析。本工作采用多种表征方法分析共沉淀法合成的Ni0.8Co0.1Mn0.1(OH)2中的杂质种类、含量及结构，杂质主要为钠、镁、钙、铁、铜、锌、铝、硫，可能分布在前驱体颗粒的晶内、晶间、晶体表面。结果表明，氨水浓度对铁、铜、锌、铝的含量影响较大。在pH值11.7条件下合成的前驱体为胶体，具有较大的比表面积，吸附的钠和硫含量最高，分别为28134.62和12898.50 μg/g。搅拌转速的变化对硫含量的分布有一定影响。优化三元前驱体共沉淀过程工艺条件对控制前驱体中杂质含量、提升最终三元正极材料电化学性能及安全性具有重要意义。

关键词: 共沉淀, Ni0.8Co0.1Mn0.1(OH)2, 氨水浓度, pH值, 搅拌转速, 杂质种类及含量