A solvent-free, flammable gas-free method is developed for the scalable synthesis of SiO_x@N-doped carbon (SiO_x@NC). The obtained SiO_x@NC manifests high specific capacity (774 mA h g⁻¹) with excellent durability in lithium storage.

SnO 2 has drawn great attention in lithium storage owing to the high theoretical capacity and appropriate lithiation potential. However, the low intrinsic conductivity and substantial volume variation severely hinder its further application in lithium-ion batteries (LIBs). Herein, we report a solvent-free carbon-coating strategy to encapsulate ultrafine SnO 2 nanoparticles into Ndoped carbon. The effective coupling of SnO 2 nanoparticles with high activity and N-doped carbon with high conductivity and mechanical stability provides the obtained SnO 2 @NC with a high reversible capacity of over 880 mAh g −1 with satisfactory durability. In situ transmission electron microscopy (TEM) characterization reveals that even with encapsulation in mechanically stable Ndoped carbon, pulverization of SnO 2 nanoparticles is unavoidable. However, the obtained SnO 2 @NC demonstrates excellent structural stability upon cycling. The scalable solvent-free synthesis, high capacity, and ideal durability make SnO 2 @NC a competitive LIB anode material.