Ultrafine SiO_x/C nanospheres and their pomegranate-like assemblies for high-performance lithium storage

The application of silicon oxide (SiO_x)-based anode materials in lithium-ion batteries is hampered by their low conductivity and large volume expansion. To tackle both issues, ultrafine SiO_x/C composite nanospheres with a uniform diameter of ∼40 nm were fabricated through a tri-component co-assembly approach. The ultrafine SiO_x/C nanospheres demonstrated a high specific capacity of 895 mA h g^-1 after 200 cycles at 200 mA g^-1. At a high current density of 1 A g^-1, a capacity of 828 mA h g^-1 could be achieved after 1000 cycles. The ultrafine SiO_x/C nanospheres were further assembled into pomegranate-like assemblies through spray drying. The resultant pomegranate-like structure manifested a discharge capacity of 1024 mA h g^-1 after 200 cycles at 500 mA g^-1.