以碳纳米管膜为纳米反应器构筑三维同轴"纳米电缆"结构的自支撑电极及其储锂性能研究

Designing electrode material with architecture of fast lithium ion/electron transportation paths is the efficient way to improve the lithium-ion battery’s properties. A designed free-standing electrode with three-dimensional (3D) “skeleton/skin” structure, consisting of 3D conductive scaffold and conformal coating of electrochemical active material, is very promising as a high performance electrode. The conformal 3D “skeleton/skin” nanostructure can not only provide the electrodes with fast charge/ion transportation and render the electrodes with flexibility, but also reduce the content of inactive additive thus increasing the energy density.However, the challenges for making the free-standing electrode with 3D “skeleton/skin” structure are how to simply and greenly construct the 3D conductive scaffold and how to make the active material conformably and uniformly coat on the conductive scaffold.. By taking the advantage of the fantastic properties of CNT, we propose a simply and green method to fabricate the free-standing electrode. An interconnected 3D CNT film (foam) is proposed to be fabricated and used as a nanoreactor to controllable loading of active material to form the 3D “skeleton/skin” structure. In the study, we will simply construct a 3D connected CNT film (foam) and disclose the key factors affecting its properties. Then, we will try to make the electrochemical active material conformal coating on the CNT, forming “skeleton/skin” structure. We will figure out what synthesis conditions are the key factors determine the conformal coating. Lastly, we will test the electrode and obtain the relationship of the micro/nanostructure of electrode with its electrochemical performance.. This work aims to provide some guidelines to combine the active material with nano-current collector for fabrication of free-standing electrode with special structure. The implement of our project will find solution to render the new power sources with greater diversity, flexibility and higher energy density.

提高锂离子电池性能的关键是构建电子、离子协同高速传输的电极材料。具有三维同轴“纳米电缆”结构（内部三维导电骨架，外部同轴共成型负载活性物质）的自支撑式电极，为解决电子/离子界面传输势垒大、非活性物质比重高、加工性能差等问题提供了新思路。制备这种电极的难点是三维导电骨架的简单绿色构筑和活性物质的可控共成型负载。针对这些难点，本项目利用碳纳米管易形成三维导电网络和可控同轴复合的特点，提出以三维碳纳米管膜为纳米反应器，在表面原位可控生长活性物质来构建三维同轴“纳米电缆”结构，简单绿色制备高性能自支撑电极。主要探索三维连通的多孔碳纳米管网络的构筑条件以及形成机理；研究碳纳米管和活性物质共成型复合的关键条件；研究复合材料的电化学性能，揭示材料的结构、组成和性能之间的内在联系。本项目的开展有望为活性物质和集流体的集成提供科学指导，有望为研制新一代轻型、柔性、高性能电源提供理论和科学依据。

提高锂离子电池性能的关键是构建电子、离子协同高速传输的电极材料。本项目利用碳纳米管易形成三维导电网络和可控同轴复合的特点，以三维碳纳米管膜为“纳米反应器”，在表面原位可控生长活性物质来构建三维同轴“纳米电缆”结构制备高性能自支撑电极，并将此概论扩展到以石墨烯膜为“纳米反应器”构建电子、离子协同高速传输的电极材料。.开发了葡萄糖水热原位绿色修饰碳纳米管的方法，实现对碳纳米管的批量表面功能化，扩展碳纳米管的应用范围。掌握以碳纳米管膜（或石墨烯泡沫）为纳米反应器制备自支撑的复合电极材料的新方法，研究了自支撑复合电极材料的结构、表面/界面和性能调控工艺，得到了复合电极材料结构与性能的构效关系，获得具有高容量、长循环、快速充放电特性的自支撑式材料（rGO-TiO2 (TNR)，CNT-TiO2，CNT-LiMn2O4等多种正，负电极复合材料）。通过多种手段分析，探讨了自支撑电极材料的微观结构和电池充放电性能、循环稳定性的关系。得出影响复合材料电化学稳定性和电化学倍率性能的关键因素是导电网络和活性物质的复合方式，良好的三维导电网络和与共成型的复合结构是实现大电流充放电和保证长周期循环电化学性质稳定的关键。因此，本项目的开展为活性物质和集流体的集成提供科学指导，为研制新一代轻型、柔性、高性能电源提供一定的理论和科学依据。.在项目执行期间共发表学术论文8篇。获得3个授权中国发明专利、申请了5个中国发明专利。项目负责人在2016年获得四川省杰出青年基金资助，2017年获得成都市“蓉漂计划”特聘专家称号。在人才培养方面指导5名硕士毕业，目前在读博士生2人，硕士生3人，其中三名硕士获得国家级奖学金。