Nanosilicon anodes for high performance rechargeable batteries

Taking advantage of an extremely high theoretical capacity of 4200 mAh g⁻¹, silicon has been considered one of the most promising anode materials for lithium ion batteries. Nevertheless, it also has many challenging issues, such as large volume expansion, poor electrical conductivity and the formation of unstable solid electrolyte interphase layers. To address these challenges, much effort has been directed towards developing new strategies, such as designing novel nanosilicon and hybridizing with other functional materials. This paper is dedicated to identifying the current state-of-the-art fabrication methods of nanosilicon, including ball milling, chemical vapor deposition, metal-assisted chemical etching and magnesiothermic reduction, as well as the design principles and the selection criteria for fabricating high performance Si nanostructures. The critical factors determining the electrical conductivity, structural stability and active material content are elucidated as important criteria for designing Si-based composites. The structural evolution and reaction mechanisms of nanosilicon electrodes studied by in situ experiments are discussed, offering new insights into how advanced Si electrodes can be designed. Emerging applications of Si electrodes in other rechargeable batteries, such as Li-S, Li-O₂ and Na-ion batteries are also summarized. The challenges encountered for future development of reliable Si electrodes for real-world applications are proposed.