化学氧键增强高容量合金化钠电复合负极材料的构筑与储钠机理研究

Recently, sodium ion batteries (SIBs) have been drawn much attentions due to their numerous advantages, such as abundant sodium resources, low-cost and environmental benignity, making them be a new research focus of energy storage. Among the electrode materials of SIBs, the elemental materials of Groups IVA and VA in the Periodic Table of Elements should be one class of important anode materials with high specific capacity. However, they usually cannot exhibit their superior electrochemical properties due to the tremendous volumetric changes during cycling, as well as the resulted huge stress, unstable surface/interface and invalidation of conductive networks. In this proposal, we plan to improve their Na-storage performances by constructing chemical M-O-G bonds (where M is the typical Sb, Sn and Si, and G represents conductive graphene-based networks) between M nanoparticles and G nanosheets in addition to our previous research outputs of G-based network, efficient voids and stable surface/interface. The designed nanohybrids can be abbreviated as (M-O-G/□)@SL, in which □ and SL represents the voids and stabilized layers (SL) respectively. When used as anode for sodium ion batteries, while the graphene-based network and reserved voids can prevent the invalid of conductive network, the continuous growth of surface electrolyte interphase (SEI) and the cracking of electrode, the M-O-G bonds and stabilized surface have the abilities of avoiding the dynamic aggregation of active metal nanoparticles and restacking of graphene nanosheets, which will dynamically stabilize the sodiation/desodiation processes and hence optimize the Na-storage properties. In addition, we will also fully evaluate the electrochemical properties of the as-prepared nanohybrids by employing various in(ex)-situ technologies when used as anode materials for SIBs, and further obtain the scientific relationships and rules between nanostructures and electrode kinetics, ionic/electronic transportations, characteristics of interfaces. After finished this project, we can not only improve the electrochemical properties of the related high-capacity anode materials, but also promote the rapid development of SIB. Therefore, the present project will lay the scientific and material foundation of high-performance SIBs, making it be very important scientifically and practically.

钠离子电池（SIB）的快速发展和潜在价格优势使其成为了电化学储能领域新的研究热点和重点。元素周期表中IVA和VA族的单质材料，是SIB高容量负极的优秀备选材料，具有重要的研究价值。针对其中的M（M = Sb、Sn和Si）单质，本项目拟在前期石墨烯（G）基导电网络、预留空间和稳定化表界面设计的基础上，重点研究G与纳米颗粒M间化学氧键M-O-G的可控构筑及其对钠电性能的提升机理。在该设计中，G基导电网络和预留空位，可有效改善体积效应导致的导电网络失效、SEI膜过厚持续生长和电极龟裂等问题，而M-O-G和稳定化表界面则能防止纳米颗粒M的动态聚集与G片层的重新堆叠，有效实现钠化/去钠化时二者的动态稳定化，最优化其钠电性能。此外，在可控制备基础上，将借助各类（非）原位表征技术，探明各结构特征改善储钠性能的科学规律，深入研究化学氧键的作用机理，认识科学本质，为开发高性能SIB奠定科学和物质基础。

钠离子电池是未来大规模储能系统的最佳候选体系之一，近年来受到了相关领域科研工作者们的广泛关注。开发高性能电极材料，是钠离子电池实用化的关键。在本项目实施过程中，主要研究了高性能负极材料中高稳定性微纳、导电结构和化学相互作用的可控构筑，并对相应材料储钠性能和全电池特性进行了全面的研究分析，揭示了相应的性能提升机理。对于合金类负极材料，发现活性纳米颗粒与石墨烯间存在的化学氧键相互作用，对于提升电化学性能发挥着重要的作用，并通过半原位结构表征和电化学分析技术，揭示了化学氧键相互作用在电化学过程中的可逆性和持久性。对硫属化合物和磷化物负极材料，进行高效导电网络的构筑，有效提升了相应的电化学储钠和钠离子全电池性能，同时通过多种原位和半原位研究技术，提出/揭示了相应的储钠机理。在制得高性能复合负极材料的基础上，与NASICON结构高电压高比能Na3V2(PO4)2O2F正极材料进行了匹配性研究，开发了多个性能优异的钠离子全电池体系。本项目的实施，不仅为高性能钠电负极材料的发展提供了材料和理论依据，还为钠离子电池技术的发展和产业化奠定了基础。项目实施过程中，共发表了第一标注论文38篇，其中包括4篇Advanced Materials、1篇Energy & Environmental Science和3篇Advanced Energy Materials等；授权发明专利4项，申请暂未授权发明专利3项；培养了吉林省第七批拔尖创新人才1人，毕业博士研究生3人，硕士研究生4人；培养了在站博士后1人，并获得“博士后创新人才支持计划”资助。