磁性三维Fe3O4/CoPt/TiO2纳米管阵列复合负极材料的构建及微磁场对嵌脱锂作用机制研究

Fe3O4 is concerned as a very promising anode material for lithium-ion batteries. However, its application is hindered due to its poor cycling stability and low rate performance. In this project, a novel composite anode of magnetic three-dimensional (3D) Fe3O4/CoPt/TiO2 nanotube array (TNTA) was designed, which exhibit excellent cycling performance and rate capability by the contributions of magnetic field assistance and TNTA composite. 1) Magnetic field assistance benefits the cycling performance of Fe3O4, because the stable magnetic field created by CoPt permanent magnet coating adsorbs the chalked Fe3O4 particles directionally, the magnetic force prohibit the mass agglomeration of Fe3O4, and the CoPt coating also provide electrical contact to Fe3O4. 2) TNTA composite anode exhibits excellent electrochemical performance due to the 3D nanotubular structure of TNTA, which improves the rate performance of Fe3O4, buffers the inflation, prohibits agglomeration and provides a rapid transmission channel for Li+. At the same time the addition of Fe3O4 enhances the capacity of TNTA. The research contents of this project include the control mechanism of the phase and microstructure, the affect factors and mechanism of the phase and microstructure on electrochemical and magnetics performance. And the rules of diffusion of charge and Li+ in the new system will be studied. What is more, the internal relationship between magnetic and electrochemical performance will be studied intensively, the acting mechanism of micromagnetic field on lithium intercalation-detercalation will be clarified, and then a theoretical model is established. This project will enrich the theory of the magnet electrode materials such as Fe3O4, and it will have an evident and practical significance on the preparation and application of new anode materials.

Fe3O4是一种极有前途的锂离子电池负极材料，但其循环稳定性差和倍率性能较低。本项目提出磁场辅助及与TiO2纳米管阵列（TNTA）复合互补的学术思路，构建磁性三维Fe3O4/CoPt/TNTA复合负极材料解决以上问题。利用永磁CoPt的稳定磁场定向吸附粉化的Fe3O4微粒、抑制团聚，提供电接触，提高循环性能（即磁场辅助）；利用TNTA三维纳米管状结构提高倍率性能、缓冲膨胀、防止团聚、提供锂离子快速传输通道，而Fe3O4提高了TNTA的容量（即Fe3O4与TNTA优势互补）。研究该复合负极材料物相与显微结构的调控规律，阐明其对电化学、磁学性能的影响规律和作用机理；研究新体系内电荷和锂离子的扩散和传输规律, 探讨磁学性能和电化学性能间的内在关系，揭示微磁场对嵌脱锂过程的作用机制，建立理论模型。本项目的实施将丰富Fe3O4等磁性电极材料的理论研究，同时对新型负极材料的制备与应用具有显著实际意义。

Fe3O4是一种极有前途的锂离子电池负极材料，但其循环稳定性差和倍率性能较低。本项目提出磁场辅助及与TiO2纳米管阵列（TNTA）复合的学术思路，制备磁性三维Fe3O4/CoPt/TNTA复合负极材料解决以上问题。利用永磁CoPt的稳定磁场定向吸附粉化的Fe3O4微粒、抑制团聚，提供电接触，提高循环性能（即磁场辅助）；利用TNTA三维纳米管状结构提高倍率性能、缓冲膨胀、防止团聚、提供锂离子快速传输通道，而Fe3O4提高了TNTA的容量（即Fe3O4与TNTA优势互补）。研究该复合负极材料物相与显微结构的调控规律，阐明其对电化学、磁学性能的影响规律和作用机理；研究新体系内电荷和锂离子的扩散和传输规律, 探讨磁学性能和电化学性能间的内在关系，揭示微磁场对嵌脱锂过程的作用机制，建立理论模型。本项目的实施将丰富Fe3O4等磁性电极材料的理论研究，同时对新型负极材料的制备与应用具有显著的实际意义。在本项目的资助下发表论文7篇和2个专利，其中3篇为TOP1区论文，一篇列为ESI高被引论文。