In Situ Wrapping SiO with Carbon Nanotubes as Anode Material for High-Performance Li-Ion Batteries

Silicon-based material as lithium-ion anodes has attracted huge attention owing to their ultrahigh capacity. However, they usually undergo severe volume expansion over the repeated lithiation/delithiation processes and have low electronic conductivity, leading to the inferior cycling stability and the poor rate capability. Here, an in-situ growth of carbon nanotubes (CNTs) on the surface of SiO composite was prepared and then encapsulated by the amorphous carbon derived from high softening point pitch. SEM and TEM studies show that SiO was firmly wrapped with CNTs and well coated with the amorphous carbon. Meanwhile, nitrogen adsorption-desorption measurement indicated the prepared composite SiO@CNTs/C was hierarchical pore structure, which can shorten the lithium-ion transport pathway and enhance the structural stability. The prepared SiO@CNTs/C exhibited an excellent long-term cycling stability (a high reversible specific capacity of 821.7 mAh g(-1), and a high capacity retention of 95.9% to the 3rd cycle after 200 cycles), and prominent rate capacity, indicating the great potential of SiO@CNTs/C anode for practical application.