硅基材料由于其具有高的能量密度，适中的充放电平台和丰富的储量成为最具有潜力的下一代锂离子电池负极材料之一。但其差的循环稳定性阻碍了在实际中的应用，提高硅基材料的循环稳定性就成为了关键问题。本论文从硅与电解液之间的本征化学反应出发，以此来开展研究。主要研究成果如下：1.发现了硅与电解液之间的本征化学反应会在充放电的过程中持续发生。通过对反应机理进行研究，发现硅与电解液之间的化学反应主要来源于氟离子对硅的腐蚀。进一步地发现硅表面包覆的碳层会加速副反应的发生，促进Li2SiF6结晶体的生成，进而加速硅基材料的失效。通过在充放电的过程中增加静置时间进一步验证在实际电化学体系下副反应的发生，根据结果发现生成的固体电解质界面(SEI)并不能阻止氟离子的渗入，抑制副反应的发生。2.为了对副反应进行有效的抑制，需要在硅基材料表面引入一层保护层来抑制氟离子的渗入。同时保护层又不能影响锂离子的传输，因此所引入的保护层具有选择性透过层的作用。本论文中发现纳米厚度的陶瓷层具有选择性透过层的作用，可以抑制氟离子的渗入，同时又不影响锂离子的传输。包覆上陶瓷层的硅基负极材料能够有效抑制副反应的发生，维持充放电过程中锂离子的传输，进而提高材料的循环稳定性。3.在各种陶瓷材料中，碳化硅是最优的选择。因此接下来利用流化床技术对循环性能优异的Si@SiC@C材料进行了宏量制备。在制备的过程中，发现了痕量金属杂质对碳化硅包覆均匀性的影响，对应的对反应器材质提出了严格的要求。针对纳米粉体难以均匀流化的问题，通过喷雾造粒的方式，将其转变为能够均匀流化的二次颗粒，最终实现了每天公斤级的制备。综上所述，本论文在硅基材料与电解液之间的本征化学反应的基础上对反应机理进行了深入探究，并对副反应的抑制提出了有效策略，为提高硅基负极材料循环稳定性提供了新思路，有效指导了硅基负极材料的发展。

Silicon based material has become one of the most potential anode materials for lithium ion batteries，due to its high energy density, moderate charging and discharging platform and abundant reserves. However, its poor cyclic stability limits its practical application. It has become a key challenge to enhance the cyclic stability of silicon-based materials. This thesis focused on the side reaction between the silicon and electrolyte and had a systematic study. The main research results are as follows:1. The side reaction between the silicon and electrolyte was found, which would take place constantly during the charge and discharge process. And the reaction originated from the corrosion of fluorion ion to silicon. The reaction product Li2SiF6 aggregation would destroy the stability of the interphase and cause the failure of silicon-based materials. What’s worse, the nano carbon on the silicon surface had a catalytic effect for the side reaction, which would accelerate the failure process of silicon-based materials. the side reaction was further proved by increase the standing time after a complete charge and discharge cycle. And according to the results, it was concluded that the SEI on the surface of silicon could not suppress the penetration of fluorine.2. To suppress the side reaction effectively, a protective layer should be designed on the surface of silicon, which could suppress the penetration of fluorine to protect the silicon. In addition, the protective layer should also have the character to get the lithium ion and electron through. Herein, we found that nano ceramic layer has the function of a selective blocking layer, which could not only suppress the side reaction but also get the lithium ion and electron through. And the cycling performance was enhanced significantly after the introduce of nano ceramic layer.3. Among the ceramic candidates, silicon carbide had the best performance, so it is meaningful to produce the materials in a large scale to accelerate the process of commercialization and industrialization. A fluidied bed reactor was selected to produce the Si@SiC@C in a kilogram scale uniformly. In addition, the mechanism of silicon carbide forming was studied to guarantee the integrity of the silicon carbide layer. According to the in-situ TEM results, the trace metal impurity had a serious influence on the integrity of the ceramic layer. What’s more, spray granulation was used to change nano particles into secondary particles in micrometers, making the particles have a good fluidized state. The good fluidized state could ensure the uniformity of the final products.In summary, this thesis has conducted an in-depth study for the reaction mechanism about the intrinsic chemical reaction between silicon and electrolyte, and proposed effective strategies to inhibit the side reaction. An attractive perspective was proposed to enhance the performance of silicon anode and guide its development effectively.