Strategies to succeed in improving the lithium-ion storage properties of silicon nanomaterials

Abstract

Silicon is of scientific and practical interest in lithium-ion batteries (LIBs) due to its natural abundance, low toxicity, moderate working potential, and high theoretical capacity. However, its huge volume variation during lithiation and delithiation processes leads to the pulverization of silicon particles and subsequently results in fast capacity fade of the electrodes. Furthermore, the intrinsic electric conductivity of Si is relatively low and lithium diffusion in Si is rather slow. These issues hinder the practical application of Si in LIBs. In the past decade, significant improvements in the anode's cycleability and rate capability have been achieved by the control of the nanostructure and morphology of the Si electrode and incorporation of conductive species. In this review, the preparation methods and electrochemical performance of these Si electrode nanomaterials are summarised. The mechanisms behind the performance enhancement are illustrated. Moreover, factors that affect the performance of Si anodes, such as electrolyte additives, binders, and current collectors, are also discussed. We aim to shed some light on some emerging directions for future research on Si anodes in LIBs.