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

Silicon anodes with an extremely high theoretical specific capacity of 4,200 mAh g 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 composites were prepared using a simple spray drying process, during which silicon nanoparticles reacted with oxygen and generated SiO on the surface. The thickness of the SiO layer was tuned by adjusting the drying temperature. In the unique architecture, the SiO 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 composites dried at 180°C delivered a high specific capacity of 1746.5 mAh g after 300 cycles at 500 mA g.