Micro-Silicon as Anodes for High-Cycle-Life Lithium-Ion Batteries.

Silicon (Si) is regarded as a promising anode material for next-generation lithium-ion batteries (LIBs) due to its exceptionally high theoretical specific capacity. However, the large volumetric change that occurs during lithiation and delithiation has hindered the practical implementation of Si anodes, even though nano-Si (n-Si) shows improved cycling capability. This review examines the emerging strategies of increasing battery performance using feasible micro-Si (μ-Si) as anode. Trade-offs between performance, cost, and scalability of n-Si and µ-Si are compared. Porous Si architecture is explored to accommodate volume expansion while preserving electrical integrity. Electrolyte design, including high-concentration electrolytes and functional additives, is reviewed in the context of promoting stable solid electrolyte interphase (SEI) formation on μ-Si surfaces. Coating strategies such as carbon, polymer, and metal oxide coatings as well as compositing μ-Si with conductive matrices are discussed for their roles in buffering mechanical strain and enhancing electrochemical performance. Finally, the economic and practical implications of using metallurgical-grade µ-Si and scalable processing techniques are analyzed, providing insight into the viability of μ-Si-based anodes for commercial applications. This review aims to guide future research toward the development of high-energy density, long-life LIBs using earth-abundant and industrially relevant µ-Si materials.