Bamboo leaf derived ultrafine Si nanoparticles and Si/C nanocomposites for high-performance Li-ion battery anodes

Silicon-based nanomaterials are promising anode materials in lithium-ion batteries (LIBs) due to their high theoretical capacity of 4200 mA h g^-1, more than 10 times that of commercial graphite. Si nanoparticles (NPs) with a diameter of or below 10 nm generally exhibit enhanced lithium storage properties due to their small size and large surface area. However, it is challenging to generate such ultrafine Si NPs by a facile and scalable method. This paper reports a scalable method to fabricate ultrafine Si NPs 5-8 nm in size from dead bamboo leaves (BLs) by thermally decomposing the organic matter, followed by magnesiothermic reduction in the presence of NaCl as a heat scavenger. The ultrafine Si NPs show a high capacity of 1800 mA h g^-1 at a 0.2 C (1 C = 4200 mA g^-1) rate and are thus promising anode materials in lithium-ion batteries. To achieve better rate capability, the BLs-derived ultrafine Si NPs are coated with a thin amorphous carbon layer (Si