高容量过渡金属-氧-碳钾电复合负极材料的可控构筑与储钾机理研究

Recently, potassium-ion batteries (KIBs) have been drawn much attentions due to their numerous advantages, such as abundant potassium resources and low-cost, making them be a new research focus of energy storage. Among the electrode materials of KIBs, the transition metal oxides based on the conversion reaction should be one class of important anode materials with high specific capacity. However, they usually cannot exhibit their superior K-storage performances due to the tremendous volumetric changes during cycling and poor cycling stability. Based on abovementioned disadvantages, we plan to improve their K-storage performances by in situ constructing unique transition metal-oxygen-carbon nanohybrids (M-O-C, where M is the typical Fe, Mn, Ni, Cu and Zn) between M and graphene (G) nanosheets. Meanwhile we will focus on the controllable preparation of M-O-C and their boosted mechanism on K-storage performance. When used as anode for KIBs, the volume effect can be effectively improved by designing graphene-based network, meanwhile the M-O-C nanostructure and its stabilized surface/interface have the abilities of avoiding the dynamic aggregation of between M-O-C nanoparticles, which will dynamically stabilize the potassiation/depotassiation processes and hence optimize the K-storage properties. In addition, we will full evaluate the K-storage properties/mechanisms of the M-O-C nanohybrids by employing various in(ex) situ characterization technologies, and further gain the scientific relationships and rules between M-O-C nanoarchitecture and K-storage performance in KIBs. It will lay the scientific and material foundation for developing high-performance KIBs.

钾离子电池(KIBs)潜在的资源和成本优势使其成为了电化学储能领域新的研究热点。在各类电极材料中，基于转化反应的第一过渡系金属氧化物，是KIBs高容量负极的优秀候选材料，具有重要的研究价值。然而，金属氧化物用于KIBs负极时表现出低的储钾活性、大的体积效应和差的循环稳定性等问题。针对这些缺点，本项目选择第一过渡系列金属(M=Fe、Mn、Ni、Cu和Zn)氧化物作为研究对象，重点研究石墨烯(G)与M间金属-氧-碳(M-O-C)复合材料的可控构筑方法及其对储钾性能的提升机理。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，而M-O-C及其稳定化的表界面则能有效实现钾化/去钾化时复合材料的动态稳定化，使其储钾性能最优化。此外，还将借助各类(非)原位表征技术，探明M-O-C微纳结构提升金属氧化物储钾性能的科学规律，深入研究其储钾机理，认识其科学本质，为开发高性能KIBs奠定科学和物质基础。

钾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，是钾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、金属-氧-碳键和化学相互作用的可控构筑，并对相应材料储钾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。对于转化类负极材料，发现活性纳米颗粒与碳基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钾性能和钾离子全电池性能，同时通过多种原位和半原位研究技术，提出/揭示了相应的储钾机理。在制得高性能复合负极材料的基础上，与高电压高比能普鲁士蓝正极材料进行了匹配性研究，开发了多个性能优异的钾离子全电池体系。本项目的实施，不仅为高性能钾电负极材料的发展提供了材料和理论依据，还为钾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SCI论文5篇，其中包括1篇Chemical Society reviews、1篇Journal of Materials Chemistry A、1篇Inorganic Chemistry Frontiers、1篇Small methods、1篇Chinese Chemical Letters和1篇ChemElectroChem等；授权发明专利7项，申请暂未授权发明专利2项；培养了毕业硕士研究生1人。