循环流化床化学气相沉积制备锂离子电池硅/碳复合负极材料的研究

Silicon based composite is supposed to be the most promising anode materials for the next-generation high-performance lithium ion batteries. The comprehension in the development of preparation method, structure design and relationship of structure-component-property of the application-oriented Si based materials is still the key point. Chemical vapor deposition (CVD) method is one of the main ways to prepare the Si based composites at present, especially for silicon/carbon composites, but it takes some disadvantages, such as high raw Si source cost, complicated process, unstable performance and difficulty in large scale production. This project will focus on the synthesis of Si/C composites on various carbon spheres (commercial graphite microspheres and prepared carbon microspheres with carbon black via Spray Drying techniques) via Circulating Fluidized Bed Chemical vapor deposition with SiH4, CH3SiCl3 as sources based on previous investigations. During the reaction, sphericity, uniform structure, and composition of Si and C will be studied. Si/C composite will be investigated to understand the fluidized bed chemical vapor deposition mechanism, formation process, distribution of various elements to optimize the process parameters. The electrochemical properties of Si/C composite will be researched for lithium ion batteries. The lithiation-delithiation mechanism, volume change during the cycling process, interfacial effect within the composites and formation of SEI will be explored for disclosing the relationship of structure-component-property. The successful implementation of this project will be very significant for the development of low cost and large-scale manufacture of Si/C composite for lithium ion batteries.

硅基复合材料普遍认为是下一代高性能锂离子电池负极材料的首选。面向应用的材料的制备方法、结构设计、构效关系的全面理解仍然是发展硅负极面临的最关键的问题。目前化学气相沉积（CVD）法是制备硅基负极材料的主要手段之一，尤其是Si/C复合材料，但主要存在制备过程复杂、成本高、批量生产困难、性能不稳定等问题。本项目在原有基础上，将研究化工行业广泛使用的循环流化床技术，以硅烷和氯硅烷等为原料，通过CVD过程，在不同球形碳材料（商业石墨微球和纳米炭黑喷雾成球制备碳微球）表面沉积含硅组分，形成分散性好、球形度高、均匀的Si/C微球复合负极材料，研究流化床CVD过程机理，优化工艺参数，评价复合负极材料的电化学性能，研究制备的Si/C复合材料脱嵌锂机理、体积效应、SEI膜、动力学特性，掌握结构-组成-性能之间的构效关系，为发展低成本、批量制备硅碳复合负极材料奠定科学基础。

硅基复合材料普遍认为是下一代高性能锂离子电池负极材料的首选。面向应用的材料的制备方法、结构设计、构效关系的全面理解仍然是发展硅负极面临的最关键的问题。目前化学气相沉积（CVD）法是制备硅基负极材料的主要手段之一，该项目在原有基础上，研究了化工行业广泛使用的流化床、固定床气相沉积技术以及喷雾造粒等，以甲基氯硅烷等为原料，通过CVD过程，在不同球形碳材料（商业石墨微球和纳米炭黑喷雾成球制备碳微球）表面沉积含硅组分，形成分散性好、球形度高、均匀的Si/C微球复合负极材料，优化工艺参数，评价复合负极材料的电化学性能，研究制备的Si/C复合材料脱嵌锂机理、体积效应、SEI膜、动力学特性，为发展低成本、批量制备硅碳复合负极材料奠定科学基础。