基于Li+离子流调控的金属/碳基复合材料用于长寿命锂金属负极的研究

Li金属充放电过程中易形成枝晶，导致电池库伦效率降低、极化增大和严重的容量衰减，甚至隔膜刺穿造成安全隐患。为了解决该问题，国内外的研究者采用了SEI膜优化、三维集流体、增强基底亲锂性、改善锂离子迁移性等改良策略，然而Li金属负极在高电流密度、高面积容量下的库伦效率以及循环性能仍不能满足实际应用的需求。Li+离子流调控被认为是一类更有效的Li负极优化策略。本项目将从改善基底材料的本征亲Li性、电极界面处Li+迁移速率以及电极局域电场分布这三个角度调控Li+离子流，抑制Li枝晶的产生。先通过理论模拟指导材料设计，筛选出适合的材料组成和构型；然后优化材料设计，通过多要素耦合实现对Li+离子流的精准调控，抑制Li枝晶的产生，开发高性能Li金属电池；最后结合先进表征技术和电化学性能，从原子尺度上阐释材料的局域结构演化规律及其对电化学性能的影响，加深对Li沉积过程的理解。

The emergence and further growth of lithium dendrite in the charge/discharge process of lithium metal battery may damage the cycling stability, lower down the coulombic efficiency, lead to a large polarization and even the safety issues due to the penetration of dendrites through the separator. Various attempts have been employed in previous studies including the optimization of SEI film, three-dimensional current collector, enhancing the lithiopilicity of the substrate, improving the mobility of lithium ion, etc. However, the coulombic efficiency and cycling stability of lithium metal battery under the condition of high current density and high areal capacity are still unsatisfactory. The regulation of lithium ion flux is regarded as an effective strategy to optimize the performance of lithium metal anode. In this project, we'd like to solve these problems by controlling lithium ion flux based on the optimization of the intrinsic lithiophilicity of the substrate of anode, lithium ion migration, and the distribution of the local electric field. Firstly, we will employ the theoretical calculation to guide the material design and screen the potential materials and structural configuration. After that, we conduct the material design and regulate the lithium ion flux through the multi-factor coupling in order to eliminate the lithium dendrite and develop a high performance lithium metal battery. At last, we will demonstrate the rule of the local structure evolution of the anode material and the influence of the evolution on the electrochemical performance of Li anode by analyzing the characterization results and performance of the material, which may take a new insight on the process of the plating of lithium.