应用镁金属化学还原法制备多孔Si/Si-O-C负极材料机理研究

以二乙烯基苯和聚硅氧烷为原料经先驱体转化法制备Si-O-C材料，利用镁金属在惰性气氛保护下高温还原制备多孔的Si/Si-O-C负极材料。利用X射线衍射、能谱分析、元素分析和场发射扫描电镜分析多孔Si/Si-O-C负极材料的组成、结构、形貌，从而研究利用镁金属化学还原法制备多孔Si/Si-O-C负极材料的机理。结果表明，镁金属在还原过程中生成MgO和Mg2SiO4等产物，经HCl洗涤后可形成多孔的Si/Si-O-C负极材料。Si/Si-O-C材料中的单质硅分布于多孔的Si-O-C相中，一定程度上可缓解Si在循环过程中产生的体积效应。利用镁金属还原Si-O-C材料制备多孔Si/Si-O-C材料是一种可行的制备方法。
Si-O-C material was prepared by a polymer-derived method using copolymer of phenyl-substituted polysiloxane and divinylbenzene as raw materials. The porous Si/Si-O-C anode material was prepared with the chemical reduction of Si-O-C material by magnesium at high temperature under argon atmosphere. The composition, structure, morphology, and formation process of porous Si/Si-O-C anode material were investigated by X-ray diffraction, energy spectrum analysis, elemental analysis and field emission scanning electron microscope. The electrochemical properties of the material were characterized by using the electrochemical test instrument. The research results show that the magnesium will react with oxygen of Si-O-C material and turn into MgO and Mg2SiO4 during the reduction process. When washed with HCl, MgO and Mg2SiO4 react with HCl and turn into MgCl2, which can dissolve in the solution. Then, the porous Si/Si-O-C anode materials are formed. The silicon distribute in the porous Si-O-C material, which can improve the cycle performance of silicon. It can confirms that the material prepared by using magnesium reduction method is a potential material for the lithium-ion battery.