废旧锂离子电池中镍钴锰的绿色回收和增值利用基础研究

The spent lithium ion batteries contain lots of valuable elements, such as nickel, cobalt, et al. which have serious environmental pollution problem. The traditional process for treatmenting the solid waste have problems, such as long process, serious environmental pollution, and so on. The project will conduct the fundamental research about nickel, cobalt and manganese green recycling from spent lithium ion batteries and value-added utilization, proposing a route that extracts nickel, cobalt and manganese simultaneously, removes the impurity elements directionally, and synthesizes the nickel, cobalt and manganese ternary precursor with short process directly. By investigating the behavior of leaching and extracting nickel, cobalt and manganese simultaneously with the impurity elements removing directionally in a complex system composed of multi component and multi phase, the thermodynamic rule and dynamics strengthening mechanism of extracting nickel cobalt and manganese will be revealed, and the physical chemistry law of extracting nickel, cobalt and manganese simultaneously and selective separation with the impurity elements will be elucidated. Through synthesizing the nickel cobalt manganese ternary precursor by co-precipitation with controlled atmosphere and investigating the effect of external field and template on the precursor microstructure, the growth mechanism of ternary precursor with divergent structure will be obtained. Implementing the project will be provide theoretical basis and technical prototype for protecting the ecological environment and pollution-free, short process and value-added utilization of scarce nickel and cobalt resources.

废旧锂离子电池中含有对环境严重污染的镍、钴等有价元素，传统方法处理这类固体废弃物存在流程长、污染大等问题。本申请拟开展废旧锂离子电池中镍钴锰的绿色回收和增值利用的基础研究，提出镍钴锰同步提取、杂质元素定向净化、短流程直接制备镍钴锰三元前驱体的思路。研究多元多相复杂体系的镍钴锰同步浸出、同步萃取及杂质元素定向沉积的行为，揭示镍钴锰浸出的热力学规律和动力学强化机制，阐明镍钴锰同步萃取和杂质元素选择性分离的物理化学规律。采用控制气氛-配合共沉淀法制备镍钴锰三元前驱体，研究外场和模板剂对前驱体微观组织的影响，揭示发散型结构三元前驱体的构筑机理。本项目为生态环境的保护和稀缺镍钴资源的无污染、短流程、增值化利用提供理论基础和技术原型。

针对传统方法处理废旧锂离子电池流程长、污染大等问题，提出了废旧锂离子电池中有价金属同步提取、杂质元素定向净化、短流程直接制备镍钴锰三元前驱体的思路，并通过掺杂包覆等改性方法定向调控正极材料电化学性能，为废旧锂离子电池中镍钴锰的绿色回收和增值利用提供理论基础：.采用硫化焙烧-水浸法成功从锂离子电池废旧正极材料中提取锂，阐明了硫化焙烧反应机制；通过工艺优化，锂的浸出率达到98.2%（焙烧温度800 ℃，混料比NCA:S=5:3，焙烧时间6 h），且镍和钴不浸出，浸出液中锂浓度可以富集至20 g L-1。.采用氨化浸出法成功从锂离子电池废旧正极材料中回收Li、Ni、Co有价金属探究了氨浸过程中锰的相变和形态变化及其对有价元素浸出的影响。通过研究不同浸出条件下浸出产物的化学和结构变化，构筑了浸出条件与产物的关系，为废旧锂离子电池中高效提取Li、Ni、Co提供了新的思路。.采用了常温硫酸浸出工艺从镍钴废料中回收Ni和Co，将其转化为Ni0.92Co0.05Mn0.03(OH)2前驱体，并以此制备了LiNi0.92Co0.05Mn0.03O2层状正极材料。这种再生正极材料具有良好的层状结构、微球形貌和优异的电化学性能。.采用原位湿化学法将W元素均匀掺入LiNi0.88Co0.09Mn0.03O2材料结构内部，深入探索了W元素掺杂对材料的物化结构及电化学性能的影响，并研究了材料的高温性能、动力学性能及储能机理；45℃高温下，以超高倍率20 C循环300周后放电比容量高达97 mA h g-1。.采用回收的有价金属制备了高镍LiNi0.88Co0.06Mn0.03Al0.03O2材料并对其进行锂硼氧化物均匀包覆改性。研究了材料的高温性能和动力学性能以及表面包覆对材料在充放电循环过程中结构、形貌变化的抑制行为。NCMA88@0.2B材料在1C倍率下常温循环300周后放电比容量可达174.9 mAh g-1，容量保持率高达87.5%，在1 C倍率和50 ℃下循环120周，容量保持率高达97.2%。.通过湿化学法成功合成了具有NASICON结构的Li2AlZr(PO4)3，并将其包覆于高镍LiNi0.92Co0.05Mn0.03O2材料表面。包覆后材料在5C倍率下的放电比容量高达181.5 mAh g-1。