硅/石墨烯纳米结构的设计构筑及储锂性能研究

The properties of functional nanostructured composites can be precisely tuned by controlling the component, structure, morphology, surface/interface, and combination mode of the building blocks. This holds a great potential for the design and application of energy-storage devices. This project is mainly focused on the development of novel nanostructure anode materials for the next-generation high power and energy-storage Li-ion batteries (LIBs). The hybrid nanostructures comprising silicon-graphene composite and different graphene-based nanostructure will be controllably fabricated, which will be used as anode materials with high capacity, high rate capability, and long cycle life. The controlled design,fabrication and formation mechanism of the nano-architecture-assemblies will be explored. The dependence of the specific capacity, rate capability, and cycle life on the component, structure, and morphology of the composite will be investigated systematically. The synergistic effect of the building blocks will be explored on the base of both the experiment and theoretical calculation results. The relationship between the nanoarchitecture and the lithium-storage performance together with the evolution mechanism will be clarified. Furthermore, we will explore the process of the electron conduction and Li-ion diffusion during the charge-discharge reactions, facilitating the controlled synthesis and future use of the high-performance anode materials in LIBs. It is expected that this research would not only provide beneficial guidance to the next-generation high-performance LIBs, but also shot light for developing advanced energy conversion and storage systems, thus promoting the interdisciplinary integration, such as, material, energy, physics and chemistry, etc.

纳米复合体的性能可以通过改变“构筑单元”的组分、结构、形貌、表面/界面及组合方式进行精确调控，这在储能器件设计与应用方面具有潜在的应用前景。本项目旨在研发一系列高性能下一代锂离子动力与储能电池新型负极材料，可控制备结构稳定且具有高能量密度、高倍率充放电性能和长循环性能的硅/石墨烯纳米复合材料。探索纳米复合体的可控设计构筑及形成机理，系统研究纳米复合体的组成、结构等对其比容量、倍率性能、循环寿命的影响，在实验和理论结合的基础上深入理解纳米组装体“构筑单元”的协同效应，揭示纳米复合结构与储锂性能的内在关系与演变规律，揭示新型设计的Si-C纳米复合电极材料在电化学反应过程中电子传导、锂离子扩散的相关机理，实现高性能锂离子电池负极材料的可控制备与应用。为开发高比能的下一代锂离子电池提供有意义的指导，为先进能量转换与储存技术的发展奠定科学基础，促进材料、能源、物理、化学等学科的交叉融合。

功能纳米复合体的性能可以通过改变“构筑单元”的组分、结构、形貌、表面/界面及组合方式进行精确调控，这在储能器件设计与应用方面具有潜在的应用前景。本项目旨在研发一些列硅/石墨烯基的锂离子电池负极材料，可控制备结构稳定且具有高能量密度、高倍率充放电性能和长循环寿命的新型硅基锂离子储能电池。本项目主要围绕设计与构筑新型的硅/石墨烯纳米复合结构，在纳米硅表面可控制备单层、双层及多层的石墨烯，实现石墨烯包覆的纳米硅粒子及石墨烯与碳纳米管分级复合的硅-碳纳米复合材料做锂离子电池负极材料，系统研究了不同层数石墨烯包覆的硅/石墨烯复合体负极的循环性能、倍率性能，以及石墨烯/碳纳米管分级纳米结构包覆的纳米硅复合体的电化学储锂性能，同时通过电池活性材料与电极集流体的合理设计组装，可以使新构筑的硅基锂离子锂电池的循环寿命达到稳定的3000~3500圈，比容量达2000~2500 mAhg-1，倍率充放电电流密度达到20Ag-1，想相关研究成果分别在 Nano Energy, 27，647-657，2016; RSC Adv. 7, 15694, 2017; Electrochimica Acta, 235, 150-157, 2017; ACS Appl. Energy Mater. 9, 4309-4315,2019; Electrochimica Acta, 329, 13475,2020 等期刊发表。本项目在实验与理论结合的基础上理解纳米组装体系的”构筑单元“的协同效应，揭示纳米复合体的设计构筑与储锂性能的内在关系和演变规律，探索新型复合体在电化学反应过程中电子传导，锂离子扩散迁移的相关机理，实现高比能锂离子电池负极材料的可控制备与应用。为开发高比能的下一代锂离子电池提供有意义的指导，为先进能量转换与储存技术的发展奠定科学基础，促进材料、能源、物理、化学等学科的交叉融合。