特殊维度镍基MOFs到二维碳基材料的直接精准转变与储能研究

Metal−organic frameworks (MOFs) with highly ordered structure, rich pore characteristics, highly-dispersed metal centers, controllable structure and diversity of species have been considered as promising candidates for the synthesis of mesoscopic scale carbon-based materials. However, the thermal transformation of MOFs directly renders the formation of new two-dimensional (2D) carbon-based materials such as carbon nanobelts and graphene nanobelts/ribbons, which was hitherto unreported in the literature. Moreover, the mechanism of the transformation also needs further study. In view of the above, the project is aimed to realize the elegant design and controlled fabrication of a series of nickel-based MOFs with different morphology and structures and the direct/precise transformation into 2D carbon-based materials including carbon nanobelts, carbon nanosheets, and graphene nanobelts/ribbons as well as their assembly structures by devising reasonable synthetic systems. The investigation of the intrinsic transformation mechanism helps us establish a new synthesis methodology for accurate preparation of new 2D carbon-based materials. Importantly, we will explore the application of specific 2D carbon-based materials in sodium/potassium storage and lithium-sulfur batteries. Further, the relationship between the structural configuration and the energy storage properties is analyzed to reveal the physical and chemical nature of the materials. A series of 2D carbon-based new energy materials are finally obtained with high performance through optimizing the preparation conditions. The related studies exhibit the academic significance and potential application prospect.

MOFs高度有序的结构，丰富的孔道特性，高度分散的金属中心，结构可控和种类多样性，被认为是一种构筑碳基介观尺度材料的理想前驱体。但是热转变MOFs直接形成新型二维碳基材料如碳纳米带和石墨烯(带)等，尚未有文献报道，对其转变机理也有待深入研究。鉴于此，本项目旨在设计合理的反应体系，实现具有特定形貌和结构的镍基MOFs的设计与合成；重点研究其到二维碳基材料包括碳纳米带、碳纳米片和石墨烯(带)等及其组装结构的直接精准转变，揭示内在的转变机制，建立新型二维碳基材料精准制备的合成新方法。探索特定二维碳基材料在储钠/钾和锂硫电池等方面的应用；深入分析特定结构与性能之间的联系，揭示其物理和化学本质，进一步优化制备条件，获得高性能的新型二维碳基新能源材料。相关研究具有重要的学术意义和潜在的应用前景。

开发低成本高性能关键电池材料，是国家能源发展的重要战略需求。对电池材料而言，介观尺度复合组装结构能够提供更多的活性位点，有利于离子迁移和电子传输，最终实现从化学能向电能的高效、快速转化，因此对其表界面微结构的合理设计和电子结构的精准调控至关重要，对无机合成化学、材料化学领域也提出了新的挑战。针对以上关键科学问题，本研究发展了新型结构导向模板的合成新策略，建立了一系列具有功能导向的碳基介观尺度复合结构模型，同时揭示了目标产物在能量存储与转化应用中的构效关系。取得了取得了如下创新性成果：1) 提出了新型结构导向的通用构筑方法，揭示原位自模板-自组装的转化机制，实现了低维碳基介观尺度复合组装结构的可控合成；如利用MOF原位自模板-自催化的转化策略，实现了石墨烯笼组装的碳纳米带的可控合成。进一步调节配体比例，利用原子化-聚集化动力学竞争，构筑了多活性位点的碳纳米海绵。进一步将结构导向合成策略拓展到单原子体系，基于原位自模板自还原普适性转化机制，建立了金属单原子库，实现了多种单原子的可控合成，简化了单原子合成方法，有效解决了锂硫电池正极硫穿梭效应和负极锂枝晶问题。2）揭示了特征结构对性能调控的影响规律，拓展新材料在钠/钾、锂硫/铅酸电池等器件的应用。为新型电池研制提供了新思路。本研究的成果构建了无机新能源材料化学的可控合成新理论和新技术，支撑了对新型储能材料和器件的系统性研制与开发，为无机化学学科的发展做出了积极贡献。