熔盐储能电池中锑基液态合金电极放电机制与调控

The long-lifespan and low-cost batteries based on liquid metal electrodes and molten salts electrolyte, redeeming the disadvantages of batteries with solid electrodes, are promising for large-scale energy storage applications. Alloying processes are the intrinsic discharge mechanism of liquid metal electrodes, which also play key roles on reducing the melting point of electrodes and then lowering the working temperature of batteries. However, the correlations of the alloying processes of liquid metal electrodes and the performances of batteries are rather vague, which hinders the development of liquid metal batteries. To understand the alloying processes of liquid metals in molten salt batteries, this proposal is focused on the study of thermodynamics on the properties of potential of antimony-based alloy electrodes, the dynamics of alloying discharge processes and those of the effects to the battery performances, via the electrochemical analysis, characterization of alloys and batteries, combing with calculation and simulation. The study will reveal the contributing mechanism of alloy components for electrode potential and the bottleneck for discharge processes of battery, and figure out the key restraining factors on the performances of antimony-based liquid metal battery. The results of the study will solidify the scientific foundation of high-voltage, high-rate and long-cycling liquid metal batteries, and promote the energy storage applications of molten salt batteries.

基于液态金属电极的熔盐储能电池寿命长、成本低，弥补了室温固态电极电池体系的不足，有望实现大规模电能存储。合金化是降低金属电极熔点和电池工作温度的重要途径，也是液态金属电极的基本放电机制。有关液态金属电极合金化过程对电池储能特性影响机制的认识尚浅，严重制约了液态金属电池的进一步发展和实际应用。为了厘清合金电极过程与储能电池属性的关系，本项目结合电化学分析、材料和电池表征、计算模拟等，以锑基合金电极为研究对象，重点研究电极电势的热力学、合金化放电过程的动力学及其对电池性能的影响，厘清合金成分对电极电势的贡献机制，理解电池放电过程的瓶颈步骤，掌握影响锑基液态金属电池储能特性的关键因素，为设计高电压、高倍率、长寿命的液态金属电池提供理论支撑，推动熔盐储能电池的实际应用。

本项目围绕熔盐储能电池锑基合金电极放电过程中的关键科学问题，从多元Sb基合金电极设计与优化理论、合金电极放电过程界面动态演化机制、大容量电池界面稳定化策略等三个方面进行了系统深入研究。分析了不同Sb基合金电极的电势变化规律，发展了系列Sb-Sn电极体系，揭示了不同Sb-Sn比例合金电极在放电过程中正极形态和放电产物演变过程；厘清了Sb基熔盐储能电池充放电过程的反应机制，分析了电池失效模式与调控方法；提出了内场分区限域策略，有效解决了熔盐储能电池放电过程的界面不稳定性问题，显著提升了大容量电池的稳定性，为发展高效稳定的锑基熔盐储能电池奠定了理论基础。