Si Alloy Negative Electrode Materials for Li-ion Batteries
Si-based negative electrode materials are promising for lithium batteries. However, Si-based negative electrode materials suffer from huge volume change, crystallization effect (Li15Si4 formation), unstable solid electrolyte interface during cycling. Preparing Si/inactive materials and Si/C compounds (especially carbon coated Si materials) are two efficient methods to alleviate these problems mentioned above. This work focuses on designing and developing new Si-transition metal negative electrode materials. Si-Mo, Si-TiN, and Si-Ti-N-O alloys were prepared by Ar milling, N2 (g) milling, and air milling, respectively. Composition, morphology, and electrochemical performance of Si-Mo, Si-TiN, and Si-Ti-N-O alloys were investigated. Thermal stability of these alloys was also studied, since high thermal stability is an important requirement for preparing carbon coated Si negative electrode materials at high temperature. A preliminary study of high temperature carbon coating preparation for these Si alloys studied in this thesis and related issues were also discussed.