钠离子电池层状过渡金属氧化物正极材料的储能机制及稳定性研究

Developing high-efficiency and stable rechargeable batteries is critical to alleviate energy and environmental problems. Sodium-ion batteries have gained a great deal of attention due to their low cost and potential application in large-scale energy storage. However, layered transition metal oxide cathode materials are still plagued with the sluggish kinetics, irreversible phase transition and poor air stability, which lead to the low capacity, poor cycle life and rate capability. The project mainly focuses on the kinetics and structural stability of layered transition metal oxide cathode materials. Ion/electron storage and transport behaviors of these materials are investigated through the state-of-the-art in-situ characterization techniques as well as theory calculation. And the phase transition process of these materials are also investigated to find the key factors to improve their kinetics and stabilize their structure. Therefore, high-efficiency and stable cathode materials will be achieved, which will give an impetus to the application of sodium-ion batteries for large-scale energy storage.

高效稳定的二次电池储能技术是具有战略意义的关键支撑技术。原料丰富的低成本钠离子电池在未来大规模储能技术领域有着潜在的应用前景。本项目面向极具应用前景的层状过渡金属氧化物，围绕其作为钠离子电池正极材料应用时的关键科学问题：即嵌脱钠反应动力学缓慢，充放电循环过程中易发生不可逆相变且空气稳定性差；利用先进的材料（原位）表征和测量技术，并结合理论计算，研究钠离子在材料体相的输运、存储、反应特性，深入探讨材料微观结构与其宏观物理化学性质之间的关系，探索相应的调控策略；以期解决限制层状过渡金属氧化物钠离子电池正极材料体系发展的瓶颈问题，开发出高效稳定的钠离子电池正极材料体系，为大规模储能用钠离子电池关键技术的发展奠定坚实的科学与材料基础。

围绕层状过渡金属氧化物嵌脱钠反应动力学缓慢和充放电过程中发生不可逆相变的关键科学问题，本项目主要通过阳离子取代调制结构，实现了电荷分布和钠离子/空位有序排布的有效调控，抑制不可逆相变，提高Na+传输动力学，获得了多种高效稳定的钠离子电池层状正极材料，解决了限制层状氧化物正极材料在钠离子电池中应用的瓶颈问题；利用先进的材料（原位）表征和测量技术，并结合理论计算，深入探讨材料微观结构与其宏观物理化学性质之间的关系，揭示了钠离子在材料体相的输运、存储、反应特性。通过对材料综合性能的优化和筛选，发展了层状正极材料的放大制备。结合正极补钠技术，实现了Ah级钠离子软包电池的批量制备，推动了层状氧化物正极材料在钠离子全电池中的应用，为大规模储能用钠离子电池关键技术的发展奠定坚实的科学与材料基础。