Recent advances and perspectives of 2D silicon: Synthesis and application for energy storage and conversion

Two-dimensional (2D) materials such as graphene have sparked great attention and research in every field. Among them, 2D silicon has wide potential applications in chemical sensor, hydrogen storage, semiconductors, electronic device, biomedicine and energy storage and conversion due to its abundant resources, environment-friendly character, unique structure and superior properties. Specially, with the fast ion transport, sufficient electrode-electrolyte contact area, huge theoretical capacity and superior activity, 2D silicon shows promising applications in energy storage and conversion such as lithium-ion batteries, lithium-oxygen batteries, lithiumsulfur batteries, sodium-ion batteries, potassium-ion batteries, magnesium-ion batteries, supercapacitor, hydrogen storage, etc. However, the challenges such as complicated synthesis process, sensitive in atmosphere, strong Van der Waals force between silicene hinder the commercialization of 2D silicon. Several effective strategies have been designed and developed on 2D silicon. In this review, we comprehensively summarize the fundamentals, advances in synthesis of 2D silicon and its application in energy storage and conversion. Eight strategies for fabrication of 2D silicon are presented and analyzed, focusing on the relationships among fabrication approaches, intrinsic structure and properties. Furthermore, this review offers a state-of-the-art development and perspectives in synthesis and energy storage applications. The vast application of 2D silicon can be a new milepost for energy storage and conversion and other aspects. In addition, the content of reviews may be referred by other 2D materials. We hope that the simplified synthesis process, improved and unique properties might promote the practical applications of 2D silicon in energy science and beyond.