柔性GeO2/Ge@TiO2纳米线复合材料的制备及其储锂性能研究

Obtaining excellent electrochemical performance and foldable property of electrode materials is the first step towards high-performance flexible lithium-ion batteries. GeO2 material is a promising anode material for Li-ions batteries due to its high theoretical capacity. However, the poor cycling stability and low Coulombic efficiency limits its development. GeO2-based composites can improve the problem, however, they are generally powder materials coated on the copper foils, leading to poor flexibility. In this research field, it has been gradually acknowledged that to achieve both high electrochemical performance and robust flexibility in GeO2-based materials is a severe challenge. To overcome the difficulties, this research proposal aims at designing and preparing GeO2-based anode material with low-dimensional nanowires structure with surface modification by metal Ge nanoparticles and TiO2 naomaterials to improve the electrochemical performance . In specific, a series of flexible “GeO2@Ge@TiO2” nanowires will be prepared by either hydrothermal method-sputter or vapor-liquid-solid-mechanism-hydrothermal methods and so on, which are used to build flexible electrodes. Afterwards, we will study the effect of the structure and metal oxide materials on their performance for lithium storage. The accomplishment of the proposed research will benefit the development of new ways of designing GeO2-based nanomaterials and promoting the application of GeO2-based material for flexible Li-ions batteries.

获得柔性且储锂性能优异的电极材料是实现高性能柔性锂离子电池的关键。氧化锗因比容量高成为人们关注研发的新型锂离子电池负极材料，但较差的循环稳定性和较低的库伦效率问题限制其发展。氧化锗基复合材料能有效改善此问题，但其基本都是粉体材料，多采用将其涂布在铜箔上，所得极片不具有良好柔韧性。如何将氧化锗基复合材料与柔性构建思路相结合，获得性能优异的柔性氧化锗基复合材料是个难题。本项目着眼于结合“Ge修饰的低维纳米线结构”与“复合TiO2”两方面优势来改善其循环稳定性、库伦效率和柔韧性，拟采用水热-镀膜结合、气-液-固(VLS)-镀膜-水热结合等方法，制备柔性GeO2/Ge@TiO2纳米线，获得柔性一体化电极，研究其储锂性能。探讨结构、所复合材料的含量等因素影响材料性能的规律，筛选出性能优异的柔性氧化锗基材料。本项目的开展可拓展低维氧化锗基复合材料的制备路线，同时将促进其在柔性锂离子电池中的应用和发展。

获得柔性且储锂性能优异的电极材料是实现高性能柔性锂离子电池的关键。氧化锗因比容量高成为人们关注研发的新型锂离子电池负极材料，但较差的循环稳定性和较低的库伦效率问题限制其发展。氧化锗基复合材料能有效改善此问题，但其基本都是粉体材料，多采用将其涂布在铜箔上，所得极片不具有良好柔韧性。如何将氧化锗基复合材料与柔性构建思路相结合，获得性能优异的柔性氧化锗基复合材料是个难题。我们通过水热-ALD镀膜、水热-ALD镀膜-还原法，成功制备了自支撑的空心的TiO2@GeO2纳米管阵列柔性一体化电极和自支撑的空心的TiO2@Ge/GeO2纳米管阵列柔性一体化电极，研究了它们储锂性能，探讨了结构、所复合材料的含量对性能的影响。本项目的开展拓展了低维氧化锗基复合材料的制备路线，同时促进了其在柔性锂离子电池中的应用和发展。另外，我们还成功制备了ZnO@TiO2的纳米棒阵列柔性一体化电极、GeO2纳米粒子柔性一体化电极和空心TiO2的纳米管阵列柔性一体化电极等。