Abstract:

Silicon-based materials are promising anode materials for the application of lithium-ion batteries. However, silicon-based anode materials also have problems such as mechanical and electrochemical instability, which limits their practical application as anode material for lithium-ion batteries. In amorphous nanostructured silicon powder, the mechanical and electrochemical instability can be effectively alleviated by reducing the particle size to nanoscale and translating the structure from crystalline to amorphous. Thus, the effective preparation of amorphous nanosilicon powder is of great significance for improving the performance of lithium-ion batteries. The preparation of amorphous nanostructured silicon powder is based on the following principles: reduction of silicon oxides or halides by adding metals or nonmetals with a strong reductant, quick freezing of liquid or gaseous silicon, and thermal decomposition of gaseous silicon. The preparations of amorphous nanosilicon powder are reviewed, including mechanical ball milling, chemical reduction, solvent heating, liquid phase quenching, and vapor deposition. The advantages and disadvantages of various preparation methods are introduced considering their economics, feasibility of industrial production, and so on. In addition, other possible methods such as plasma evaporation-condensation, spray drying, self-propagating combustion, improved Siemens method, and electrodeposition technology are described to offer more references for the preparation of amorphous nanosilicon powder.

Key words: amorphous, nanostructured silicon powder, lithium-ion battery, anode materials, preparation methods