Facile synthesis of 3D silicon/carbon nanotube capsule composites as anodes for high performance lithium ion batteries
Abstract Carbon nanotubes have attracted widespread attention as ideal materials for Lithium ion batteries (LIBs) due to their excellent conductivity, mechanical flexibility, chemical stability and extremely large surface area. Here, three dimensional (3D) silicon/carbon nanotube capsule composites (Si/CNCs) are firstly prepared via water in oil (W/O) emulsion technique with more than 75 wt% loading amount of silicon. CNCs with unique hollow sphere structure act as a 3D interconnected conductive network skeleton, and the cross linked carbon nanotubes (CNTs) of CNCs can effectively enhance the strength, flexibility and conductivity of the electrode. This Si/CNCs can not only alleviate the volume expansion, but also effectively improve the electrochemical performance of the LIBs. Such Si/CNCs electrode with the unique structure achieves a high initial discharge specific capacity of 2950 mAh g 1 and retains 1226 mAh g 1 after 100 cycles at 0.5 A g 1 as well as outstanding rate performance of 547 mAh g 1 at 10 A g 1