硅醇反应制备硅纳米颗粒及其复合负极材料的储锂性能研究

Nanostructured silicon materials are supposed to be the promising anode materials for Li-ion batteries in the future, but it takes some disadvantages, such as high raw Si cost, complicated preparation process, environmental pollution， and difficulty in large scale production. This project will focus on the fabrication of Si nanoparticles via catalytic reaction commonly used in organosilane industry. During the reaction, Si particles react directly with alcohol over Cu-based catalysts to produce alkoxy silane and the consumption of Si results in the formation of nano-particles within the residual Si materials. The effects of Si powder as reactants, Cu-based catalysts, preparation conditions, and etc. on the nanostructure of Si materials will be investigated for understanding the catalysis mechanism, nanostructure formation process, distribution of various non-Si elements. After composited with various carbon materials，the electrochemical performances of Si-based anodes will be measured. The volume change of Si during the cycling process, interfacial effect, dynamics property, and etc. within the nanoparticles will be explored for disclosing the intrinsic relationship between of structure and property. The successful implementation of this project will provide a low cost route for the large-scale manufacture of Si nanoparticles anode materials and also be very significant for the development of high power Li-ion batteries.

纳米结构硅负极材料是未来锂离子电池的理想材料，但制备过程普遍存在能耗高、工艺复杂、环境污染等问题，很难规模化生产。本项目拟利用有机硅行业广泛采用的烷氧基硅烷单体合成的硅醇反应过程，即硅与醇在铜基催化剂作用下，调节反应参数来调控硅的反应程度，直接制备不同粒径的硅纳米颗粒。选择不同硅粉和铜催化剂，控制工艺条件和反应进程，探讨硅纳米颗粒的催化形成机理、铜的分布规律及物质组成与调变机制；将硅纳米颗粒与不同碳材料复合形成硅碳微球负极材料，研究复合材料的电化学性能及其在循环过程中的体积效应、界面效应、动力学性能等，揭示材料结构特点与与电化学性能之间的本征联系。项目的顺利完成将对高性能锂离子电池负极材料的发展，以及为低成本、批量制备硅纳米颗粒奠定实验和理论基础。

纳米结构的硅基负极材料为下一代锂离子电池的理想材料，制备过程普遍存在能耗高、工艺复杂、环境污染等问题，难于实现规模化生产。本项目通过硅醇反应，通过改变反应条件，制备了多种纳米硅材料，包括纳米硅颗粒、氧化亚硅等，研究了硅醇反应过程及机理，材料与性能之间的构效关系。制备的纳米硅颗粒的粒径可以控制在150nm以下，首周可逆容量达到2327mAh/g。通过表征发现表面含有稳定的有机官能团，在电池循环过程中可以与电解液反应生成稳定的SEI，该稳定SEI的形成为硅基材料的长周期稳定循环提供了保障，循环445周之后，可逆容量为534mAh/g，远远高于商业化石墨材料。制得的氧化亚硅基负极材料，该负极材料表现出优异的电化学性能。后续通过热解的方法实现了纳米硅与碳材料的复合，制备了多种核壳结构的硅碳复合材料。项目按照计划顺利完成，纳米硅颗粒、氧化亚硅基负极材料、硅碳复合材料等多种硅基材料的高效低成本制备为高性能锂离子电池负极材料的发展，奠定了理论基础与实验保障。