“…Reducing the particle size of the Si materials from the bulk to the nanoscale, in forms including nanoparticles, , nanotubes, nanowires, and porous spheres, , can offer high interfacial area, fast electronic and ionic diffusion, and alleviation of the strain, thus demonstrating superior performance . The fabrication of Si active/inactive nanocomposites is a straightforward and effective approach to avoid direct contact between the surface of the Si and the electrolyte, and therefore, the nanocomposites maintain a relatively stable SEI film and improved cycling performance. − For example, amorphous carbon-coating strategies are attractive because of the outstanding electronic conductivity, and more importantly, they provide a barrier layer to isolate Si active materials from the electrolytes. − The compact carbon layers, unfortunately, are prone to fracture due to the rigid structure and large volume expansion of Si . An addition of void spaces around Si particles is necessary to ensure the structural integrity during the cycling process, such as by the formation of hollow core–shell, , yolk–shell, and porous structures. , Such constructions are usually accompanied by the use of hazardous hydrofluoric acid and, as well, give rise to the inferior mechanical and thermal stability .…”