LAUSR

Abstract Nanostructured-silicon with a conformal carbon coating (Si@C) is a promising anode-material for the next-generation lithium-ion battery (LIB). However, silicon nanostructure and the carbon nanocoating usually are formed in the separated processing steps, making the entire synthesis process costly, complicated and time-consuming. Herein, we propose a process in which silica nanomaterials (i.e., diatomite and stober sphere) are firstly converted into Mg2Si. After the converted Mg2Si further reacts with CaCO3, a conformal carbon nanolayer (1–5 nm) spontaneously grows on the newly formed Si nanostructures to obtain Si@C. Especially, diatomite-derived Si@C delivers a reversible capacity of 1359.7 mA h g−1 at 4 A g−1, and retains 764.6 mA h g−1 even after 500 cycles. The process reported in this study can provide a scalable way to synthesize high-performance Si@C anode materials for LIBs.