A Hollow Silicon Nanosphere/Carbon Nanotube Composite as an Anode Material for Lithium-Ion Batteries

Silicon possesses a high theoretical specific capacity and is a promising high-performance anode material for lithium-ion batteries (LIBs). However, it shows a poor cycling performance because of volume expansion. A hollow structure can improve Si cycling performance, and the template method is one of the most common methods for hollow micro /nanosphere preparation. A polystyrene (PS) microsphere has the advantages of having a uniform and controllable particle size, easy modification, and high stability, thus being an ideal template for preparing hollow structure material. Herein, PS microspheres are used as templates to obtain hollow silica spheres, and then obtain hollow silicon spheres with an inner pore diameter of similar to 50 nm by a magnesium thermal reduction method. Lithium-ion battery anode material is obtained using carbon nanotubes supporting hollow silicon spheres (Si-CNTs). Si-CNTs exhibit excellent cycling performance (1188 mAh g(-1) after 200 cycles) and excellent rate capability (484 mAh g(-1) at 1 A g(-1)). Hollow porous Si-CNTs show great potential, providing a promising idea for solving the volume expansion problem of Si.

Automated summary

Silicon has a high theoretical specific capacity as a lithium-ion battery anode material, but suffers from poor cycling performance due to volume expansion. The use of hollow structure and template method, such as polystyrene microspheres, can improve silicon's cycling performance. Hollow silicon spheres with a pore diameter of around 50 nm are obtained and used in carbon nanotubes to create lithium-ion battery anode material, which exhibits excellent cycling performance and rate capability.