新型大容量液态金属储能电池基础问题研究

The increasing demands for integration of renewable energy into grid and development of smart grid call for low-cost and long-lifetime energy storage technologies, however, the conventional battery technologies cannot meet the metrics. The liquid metal batteries (LMBs), with novel all-liquid cell design, are of merits of simple-structure, low-cost and long-lifetime, potentially meet the requirements for large-scale energy-type applications. The development of LMBs is hindered by the lack of key scientific insights into LMBs, especially on the electrode materials and interfaces in LMBs. This project is planned to investigate LMBs via three levels of electrode materials, interface properties and battery performance. The rational design of high-potential and low-melting electrode materials will be developed through materials calculation, synthesis and characterization. To reveal the correlation between interface properties and battery performance, the research will be focused on the simulation and analysis of the dynamic interfaces and the effects to battery performance. The failure mechanism of liquid metal batteries is planned to be studied as well. The LMBs system will be optimized systematically, and novel low-temperature liquid and semi-liquid metal batteries will be explored in this project. Based on our previous research on LMBs, the aims of this project are to solidify the scientific foundation of LMBs and to reinforce our leading position in LMBs research field, also to develop the next generation technology of high performance energy-type electrochemical energy storage systems for large-scale applications.

液态金属电池结构简单、成本低、寿命长，弥补了现有固态电极电池体系的不足，是一类全新的能量型电化学储能技术。目前对这一新型电化学储能体系的电极材料、界面问题和失效过程的认识尚非常初浅，严重制约了液态金属电池的进一步发展和实际应用。为了解决液态金属电池的材料和界面关键科学问题，进一步提高液态金属电池性能，本项目从电极材料-界面结构-电池行为三个层面展开研究。结合计算与实验，建立液态合金材料的构效关系，指导高电势低熔点正极的理性设计；结合模拟与原位表征，研究电池中多重液/液界面在充放电过程中的动态变化，探讨其影响电池循环性能的机制，研究电池失效模式；优化液态金属电池结构，探索全新的低温液态/半液态金属电池。在前期研究的基础上，经过4年的系统深入研究，可望使我国液态金属电池基础研究进入国际前沿，为实现下一代低成本、长寿命的能量型电化学储能技术提供科学支撑。

本项目围绕大容量液态金属电池材料和界面关键科学问题，从电极材料-界面特性-电池性能三个层面开展了系统深入研究。通过理论计算预测了电极和电解质材料的态密度、电势、熔点、扩散系数等关键物性参数，为高性能电极/电解质体系的设计提供了理论指导；构建了液态金属电池多物理场耦合模型，模拟分析了电极界面电流密度及多种流动机制对于液-液界面不稳定性的影响规律；提出了大容量电池内场调控重要策略，发展了改善集流体浸润性的关键方法，有效提升了大容量电池的稳定性，实现了400 Ah级的大容量液态金属电池的稳定运行；探究了不同工况下电池的服役特性演变规律和失效模式，评估了液态金属电池的安全特性，为推动大容量、长寿命电化学储能新技术的实际应用提供了重要基础。