With a remarkable theoretical specific capacity of ∼4200 mA h g⁻¹, silicon anodes are at the forefront of enabling lithium-ion batteries (LIBs) with ultra-high energy density. However, we have yet to see the wide utilization of silicon anodes in commercial LIBs due to several challenges, categorized as intrinsic and extrinsic problems. The intrinsic problems originate from the intrinsic properties of silicon, which include its low conductivity and massive volume expansion upon alloying with lithium. The extrinsic problems of silicon anodes are primarily associated with the laborious fabrication processes. Instead of bottom-up approaches, which involve relatively expensive and complicated synthesis routes, the top-down methods provide an affordable, controllable, and simple procedure for large-scale fabrication. The present review aims to collate the recent studies on the fabrication of silicon anodes via top-down approaches that involve etching, metallothermic reduction, and high energy ball milling. Extensive synthesis routes along with their synthesis parameters are reviewed. The morphology and the electrochemical performances of the silicon anodes prepared from various starting materials are also highlighted. Finally, perspectives on the potential future challenges and development of the top-down synthesis of silicon-based anodes are presented.

The demand for high-capacity lithium-ion batteries (LIBs) is ever-increasing. Thus, research has been focused on developing silicon-based anodes due to their high theoretical capacity and natural abundance. However, silicon-based anodes still suffer from several drawbacks (e.g., a huge volume expansion during lithiation/delithiation and the low conductivity nature of silicon). In this study, we develop a facile and low-cost synthesis route to create a composite of silicon particles and carbon nanotubes (CNTs) via simple two-step mechanical ball milling with a silicon wafer as the silicon precursor. This method produces a strong interaction between silicon particles and the CNTs, forming Si–C bonds with minimum oxidation of silicon and pulverization of the CNTs. The resulting Si/CNT anode exhibits a first cycle Coulombic efficiency of 98.06%. It retains 71.28% of its first cycle capacity of 2470 mAh g⁻¹ after 100 cycles of charge–discharge at a current density of 400 mA g⁻¹. Furthermore, the Si/CNT anode also shows a good rate capability by retaining 80.15%, and 94.56% of its first cycle capacity at a current density of 1000 mA g⁻¹ and when the current density is reduced back to 200 mA g⁻¹, respectively.