Pomegranate-Like Structured Si@SiO_x Composites With High-Capacity for Lithium-Ion Batteries

Silicon anodes with an extremely high theoretical specific capacity of 4,200 mAh g^-1 have been considered as one of the most promising anode materials for next-generation lithium-ion batteries. However, the large volume expansion during lithiation hinders its practical application. In this work, pomegranate-like Si@SiO_x composites were prepared using a simple spray drying process, during which silicon nanoparticles reacted with oxygen and generated SiO_x on the surface. The thickness of the SiO_x layer was tuned by adjusting the drying temperature. In the unique architecture, the SiO_x which serves as the protection layer and the void space in pomegranate-like structure could alleviate the volume expansion during repeated lithium insertion/extraction. As a lithium-ion battery anode, pomegranate-like Si@SiO_x composites dried at 180°C delivered a high specific capacity of 1746.5 mAh g^-1 after 300 cycles at 500 mA g^-1.