Silicon anodes in lithium-ion batteries: nanoscale engineering, composite strategies, and industrial prospects

Silicon (Si) has emerged as one of the most promising anode materials for next-generation lithium-ion batteries (LIBs) due to its extremely high theoretical capacity (3579 mAh g^-1), abundant reserves, and inherent safety advantages over conventional graphite anodes. However, the practical application of Si anodes remains hampered by key challenges, including severe volume expansion (∼300%), an unstable solid electrolyte interface (SEI), low intrinsic conductivity, and irreversible capacity loss. Academia and industry have invested significant effort in addressing these issues through nanoscale structural engineering, Si-carbon composites, advanced polymer and inorganic binders, artificial SEI coatings, and electrolyte/interface design. Simultaneously, industry has begun to adopt scalable strategies, such as graphite-Si composite hybrids, surface encapsulation, prelithiation, and the integration of fluorinated additives and locally high electrolyte concentrations, to extend cycle life and improve manufacturability. This review focuses on the fundamental mechanisms of Si anodes, summarizes the latest research strategies from both laboratory and industrial perspectives, and explores commercialization pathways through case studies of emerging technologies and global investment. Finally, we outline future research directions and prospects for silicon anodes in advanced battery systems, emphasizing the need to balance performance, cost, and scalability. Silicon is not only a key transition material for high-energy lithium-ion batteries, but also an enabling platform for anode technologies in the post-lithium era.