三维SiOx/MXene复合材料构筑及其储锂性能研究

SiOx负极材料具有高储锂容量的突出优势，在高能量密度锂离子电池中有潜在的应用前景，对满足电动汽车等日益增长的长续航和大容量需求具有重要价值。但是，SiOx负极材料存在本征电导率较低、嵌锂过程中体积膨胀严重和固体电解质界面（SEI）膜稳定性差三方面突出问题。针对背后的关键科学问题，本项目拟通过构筑三维结构SiOx/MXene复合负极材料，利用二维MXene材料高电导率和优异的机械性能等优点，结合三维导电网络提供电子和Li+的传输通道，解决SiOx负极的低电导率问题同时缓冲其嵌脱锂过程中的体积效应；研究SiOx/MXene复合负极嵌脱锂过程中的电极结构演化及SEI膜性质，探明MXene对SiOx电极结构稳定性和SEI膜性质的影响机制，揭示MXene对复合负极电化学性能的增强机理；制备高比容量、循环稳定、可快速充放电的SiOx/MXene复合负极，为高能量密度锂离子电池设计研制奠定研究基础。

SiOx anode materials have a prominent advantage of high lithium storage capacity, which have a potential application prospect in high energy density lithium ion batteries and have important value to meet the growing long life and large capacity requirements of the electric vehicles and so on. However, SiOx anode materials have outstanding issues in three aspects, including low intrinsic conductivity, serious volume expansion in the process of Li+ intercalation and poor stability of solid electrolyte interface (SEI) film. Aiming at the key scientific problems, this project intends to solve the problem of low conductivity of SiOx materials and buffer the volume effect in the processes of Li+ intercalation and deintercalation through constructing three-dimensional structured SiOx/MXene composite anode material, taking advantage of high conductivity and excellent mechanical properties of two-dimensional MXene material and the three-dimensional conductive network to provide transmission channels for electrons and Li+. By studying the structure evolution of electrode and properties of SEI film in the processes of Li+ intercalation and deintercalation, this project will verify the influence mechanism of MXene on the structure stability and SEI stability of SiOx anode and reveal the strengthen mechanism of MXene on the electrochemical performance of the composite anode. Prepare SiOx/MXene composite anode with high specific capacity, high cyclic stability and fast charging and discharging properties and lay a foundation for the design and development of high energy density lithium ion batteries.