废旧磷酸铁锂及其原位复合材料直接在碱性二次电池中循环再利用的应用基础研究

近年来，随着磷酸铁锂电池在电动汽车，储能等领域的快速发展，将产生大量废旧磷酸铁锂材料。而现有的冶金回收工艺复杂，成本高，容易二次污染，且现有修复再生技术不成熟，严重制约其资源化再利用。针对上述问题，基于前期实验结果，本项目拟将材料化学和电化学技术应用于资源循环利用领域，提出将废旧磷酸铁锂直接或原位改性后用于碱性二次电池负极的新思路。首先，优化电极和电解液配方，重点研究磷酸铁锂电极的电化学反应过程，在微观层次上揭示材料结构、形貌变化对电性能（尤其是析氢特性）的影响及机理。其次，利用短流程原位合成技术制备磷酸铁锂原位复合材料，进一步提高其综合性能，侧重研究改性对复合材料电性能的影响及机理。最后，开展磷酸铁锂电极在新型Ni(OH)2/LiFePO4 电池体系中的应用基础研究。该研究不仅能为废旧磷酸铁锂资源化再利用提供新思路和新方法，同时也为高性能低成本铁基碱性电池的发展提供理论依据和实验基础。

In recent years, a large amount of waste lithium iron phosphate (LiFePO4) material will produce with the rapid development of LiFePO4-based lithium-ion batteries in the field of electric vehicles and energy storage. The existing metallurgical recovery process of LiFePO4 is complex, high cost, easy to secondary pollution. Also, recovery technology of spent LiFePO4 is not mature, which greatly restrict its resource recycling. According to the above problems, based on previous experimental results, this project intends to materials chemistry and electrochemical technology are applied to the field of resource recycling, proposing a new recycling idea that waste LiFePO4 material directly or after in situ modification is used as alkaline secondary battery anode material. First of all, the study on the optimization of LiFePO4 electrode and electrolyte formula is performed systematically. In the process of research, we will reveal the effect of the material structure, the morphology change on the electrochemical properties (especially the hydrogen evolution characteristics) at the micro level and study its mechanism. Secondly, in order to continue to improve the comprehensive performance of LiFePO4, an in situ synthesis technology is applied to prepare LiFePO4 composites. During the process of research, we will focus on the effect of in situ modification on the performance of LiFePO4 and reveal the relevant functional mechanism. Finally, the application of basic research of the LiFePO4 electrodes in the novel Ni(OH)2/LiFePO4 battery systems will be carried out. This project can not only develop novel ideas and new methods for the recycling of waste LiFePO4, but also provide a theoretical and experimental basis for the development of high performance low cost iron-based alkaline batteries.