Si as an anode material in Li-ion batteries—A review

Li-ion batteries are considered to be the revolutionary development in the field of energy storage. New materials with greater energy density and cyclic stability are of high priority to meet the distinctive and growing demand for energy storage across various applications. To realize the enormous potential of renewable energy and electric vehicles, our immediate focus must be on developing battery materials that store substantially more energy per unit volume, resulting in smaller, lighter and more powerful batteries. Although anode materials other than graphite have been researched but these are not commercially viable due to considerable restrictions. The most commercialized battery with graphite anode has its limitation of lesser theoretical capacity of about 374 mAh g⁻¹. Researchers are testing various materials such as transition metal oxides, carbon allotrope etc., and techniques like pre-lithiation of anode materials, to synthesize new efficient materials for ongoing as well as upcoming larger applications, to build a market for hybrid electric vehicles and to grow the green energy economy. The research community sees potential in prelithiated silicon because of its approximately tenfold capacity increase over graphite, making it a great option for tackling the issue of lesser capacity of the graphite. Researchers are continuously looking for solutions to the limitations such as electrode breaking, large volume growth, capacity fading over time and side reactions of using Si as an anode material. This review paper reports and discusses the chemistry of Li and Si as well as the effect of particle size on Si’s lithiation capabilities. Influence of particle size i.e. nano-Si and micron-Si is also discussed in detail and a comparison between them is drawn for broader aspect of ongoing research. The various solutions such as prelithiation and Si$/$C composite used to address the associated problems have also been reviewed.