铜集流体上高分散锡、硅、锗/石墨烯薄膜结构的原位构筑及其储锂性能研究

For lithium ion battery, it is very important to choose electrode with perfect structure and active materials with high capacity to improve cycle performance and high-rate capacity. Generally, the manufacture progress of electrode is always very cumbersome for materials in powder form, and will cause the adverse impact on lithium ion battery. In view of this, we prefer to fabricate active materials on Cu current collection with reasonable structure for directly battery assembling. Sn/Si/Ge based materials are acted as target substances in this project. Based on laser ablation in liquid (LAL) technology, we will synthesis colloidal precursors with high reaction activity, which have shown positive effecting on the in-situ reduction of graphene oxide. Such an active colloid will be used to in-situ grow array structure with graphene on Cu current collection to fabricate the Cu-M-rGO film electrode, and the result electrode can be directly used for assembling battery. The structure of final electrode can be adjusted by changing the reaction conditions and the kind of colloid. In order to reveal the intrinsic correlation between electrode structure and battery performance, we will analyze the formation process of Cu-M-rGO thin film electrode, and discuss the performance of Cu-M-rGO film electrode with different morphologies and structures in lithium ion battery. The lithium storage mechanism of graphene based composites will also be illustrated. As a result, this project is expected to develop a simple route to fabricate electrode in new type for lithium ion battery, and provide experimental and theoretical foundation for property optimization of lithium ion battery.

针对锂离子电池，高容量、高电子/离子迁移率的活性电极材料和合理的电极结构匹配可带来优异的充放电和高倍率性能。为避免浆料制备和电极涂层过程对电池性能的负面影响，如果能够在集流体基底上原位生长具有合理电极结构的高容量活性材料，进而直接用于电池组装将具有重要的应用价值。鉴于此，项目拟以高容量的锡、硅、锗（简称M）为电极活性材料，以液相激光熔蚀技术为手段提供具有高反应活性的电极材料前驱体，在铜集流体上原位构筑金属/类金属-还原石墨烯复合薄膜结构，通过调控Cu-M-rGO负极材料的结构与形貌，获得高性能的锂离子电池。项目将具体分析Cu-M-rGO薄膜电极的形成过程，通过对比不同形貌、结构电极的储锂性能差异，揭示Cu-M-rGO电极内部组成结构与锂离子/电子传输的内在关联性，进而诠释金属-石墨烯复合材料的储锂机理。项目的开展可望为简便、新型的锂离子电池负极制备方法及其性能优化提供实验和理论数据参考。

项目在分别考虑了改善高容量电极材料的缺点和简化电池组装过程的前提下，从优势互补的角度出发，提出并设计了Cu-M-rGO电极纳米结构体系，开展了相关的基础与应用研究。电极材料体系聚焦于金属\类金属\金属氧化物原位负载的石墨烯复合纳米体系及铜基电极结构构筑，实现了石墨烯上纳米晶的原位生长与调控，并在铜集流体上实现组装；开展了基于此类电极材料的电化学活性测试与评估。截至项目结题，项目组基于液相激光熔蚀技术获得了一系列石墨烯基纳米材料的小尺寸负载，发现其结构及组成对电极材料的电化学活性和反应性均具有重要的影响。上述研究，确立了高性能石墨烯复合纳米结构及铜基电极组装的工艺-微结构-电学性能的关联机制。同时，项目组在总结LAL法制备纳米材料的生长机制及其在电化学领域进展的基础上，探索了胶体纳米颗粒对不同基底材料的结构生长影响。项目的顺利进行，为相关科研人员的电极材料结构设计、制备和分析提供了新的思路，推动了液相激光熔蚀技术辅助Cu基底上纳米结构合成领域的发展。