Facile Spray‐Drying Synthesis of Dual‐Shell Structure Si@SiOx@Graphite/Graphene as Stable Anode for Li‐Ion Batteries

A dual‐shell structure Si@SiO x @graphite/graphene (SGGr) is prepared by large‐scale spray‐drying. In this composite, Si nanoparticles act as the core, SiO x and graphite/graphene serve as the shell. Transmission electron microscopy (TEM) studies show that Si nanoparticles are coated with a 1–2 nm SiO x layer and embedded into the sheets of graphite/graphene. Amorphous SiO x and graphite/graphene as the production layer can prevent Si directly connecting with the electrolyte and improve the entire structural stability. In addition, nitrogen adsorption–desorption measurements indicate that the prepared SGGr has a higher Brunauer–Emmett–Teller (BET) surface area (48.4 m 2 g −1 ) than pure Si (36.2 m 2 g −1 ) due to the existence of mesopores and macropores, which can shorten the lithium‐ion transport pathway and provide enough void space for accommodating the volume expansion. The prepared SGGr exhibits a high reversible specific capacity of 1089.3 mAh g −1 after 400 cycles (0.16% decay per cycle), indicating that SGGr has the great potential for industrial application for lithium‐ion batteries.