A comprehensive review of silicon anodes for high-energy lithium-ion batteries: Challenges, latest developments, and perspectives

Lithium-ion batteries (LIBs) have become the predominant and widely used energy storage systems in portable electronic devices, such as video cameras, smartphones, laptops, and plug-in hybrid vehicles, along with in stationary energy storage applications like power banks and backup energy storage systems. Moreover, they are widely used in the latest models of all electric vehicles (EVs) and hybrid electric vehicles (HEVs). However, to meet the demand for EVs and HEVs, notable improvements in commercially available LIBs are required. These include improving energy density, cycling life, power and rate capabilities, safety, and cost. In spite of the initial commercialization of LIBs in 1990 by Sony, current commercial LIBs still rely on graphite/carbon as the anode material, providing a theoretical capacity of approximately 372 mAh g⁻¹. The search is on for viable alternatives to graphite with higher capacity materials, and silicon (Si) has emerged as a promising candidate with a theoretical capacity of approximately 4200 mAh g⁻¹. However, Si anodes face several challenges, such as considerable volume expansion during the lithiation/delithiation process, which leads to significant crystallographic-related phase-induced stresses, continuous formation of a solid electrolyte interface (SEI), and cycle retention decay. The volume expansion caused by stress leads to the pulverization of Si electrodes. This results in the loss of electrical contact with the substrate or current collector, causing a significant and rapid decrease in capacity and ultimately leading to battery failure. This review explores the challenges associated with Si-based anodes, their underlying causes, and their comparative advantages over conventional anodes. Furthermore, the review discusses innovative solutions to address these challenges, such as utilizing novel binders, electrolyte additives, structural, interfacial, composite engineering techniques, and prelithiation methods. Finally, considering the material cost, the suggestion to transition entirely to using up to 100% wt. silicon for anode development is proposed, streamlining practical and commercial implementation in future LIBs.