新型中空核-壳纳米结构锂离子电池负极材料的设计、制备和性能研究

Recently, with the rapid development of electronics, information technology, new energy automobile and so on, higher requirements on the lithium-ion battery performance have been put forward, which greatly inspires the interest of research on the next-generation anode materials of lithium ion batteries with high specific capacity, long cycle life. Compared with the state-of-art commercial graphite anode materials, alloy-type anode materials (Silicon, Aluminum, Tin and so on) are considered the most promising anode materials for the future lithium ion batteries due to the higher specific capacity and energy density. However, it was found that the cycle performance decayed rapidly when the alloy-type anode materials were applied, which is believed to come from the large volume change and the subsequent pulverization of electrode materials. This project is intended to use the high-capacity silicon and aluminum as the matrix materials of the anode of the lithium-ion batteries, and the electrically and lithium-ion conductive layers (such as TiO2 and carbon) are chosen as the sheath materials. Through the design and adjustment of the hollow core-shell structure, we aim to obtain the anode materials of the lithium ion batteries with high specific capacity and long cycle life. The capacity fading mechanism of the silicon and aluminum-based anodes will also be studied using the in-situ TEM and in-situ XRD techniques, which, we believe, will be helpful to the future breakthrough in the power density, energy density and overall security of new-generation lithium-ion batteries.

近年来，随着电子、信息、新能源汽车等产业的迅猛发展，对锂离子电池的性能提出了更高的要求，激发了新一代高比容量、长循环寿命的锂离子电池负极材料的研究热潮。与目前商用的碳类负极材料相比，合金类负极材料（Si、Al、Sn等）具有更高的比容量与能量密度，被认为是最有潜力的下一代锂离子电池负极材料，但是该类负极材料在充放电循环过程中会产生巨大的体积变化，导致电极材料的粉碎和导电网络的崩溃，从而使循环性能急剧衰减。本项目拟以高比容量的硅和铝作为锂离子负极材料的基材，并选择可以同时传导电子和锂离子的材料（如TiO2、碳）作为外层包覆材料，通过中空核－壳纳米结构的设计和调控，制备出高比容量、长循环寿命的锂离子电池负极材料，并通过在充放电循环中的原位透射电镜和原位X射线衍射技术的观察，揭示硅和铝基负极材料容量衰减的机制，为未来新型锂离子电池在大功率放电、能量密度以及整体安全性等方面的重大突破提供研研究基础。

在自然科学基金的资助下，本项目按计划全面地开展了研究工作，以硅基和铝基中空核-壳纳米结构锂离子电池负极材料为主要研究内容，通过中空核－壳纳米结构的设计和调控，制备出高比容量、长循环寿命的锂离子电池负极材料，并研究了其电化学性能，揭示了其高容量和循环性能的电化学机理。全面圆满地完成了本项目的研究目标，并在此基础上，广泛地拓宽了研究内容，主要包括：开展了多种新型的锂离子电池负极材料的研究，如SnO2-Sn@C中空核壳结构锂离子电池负极材料、双壳层中空纳米结构MnO2@TiO2负极材料、采用激光烧蚀法制备一体化锂离子电池负极材料、以磁小体趋磁细菌为前驱体合成新型Fe3O4@C锂离子电池负极材料，开展了高性能固态电池用固体电解质材料、以及过渡金属硫化物超级电容器电极材料等方面的研究工作，取得了一系列有创新性的研究成果，为未来新型锂离子电池在大功率放电、能量密度以及整体安全性等方面的重大突破提供了研究基础。. 在项目执行过程中，总共发表了44篇学术论文，其中被SCI收录40篇，包括国际顶级期刊Nature Energy、Nano Energy、J. Mater. Chem. A、ACS Appl. Mater. Interfaces、J. Power Sources、J. Am. Ceram. Soc.,等；申请了6项中国发明专利，已获得3项授权；联合申请了2项美国发明专利；共培养博士后2名，毕业博士5名，毕业硕士1名；此外还有在读的博士研究生6名。