Flexible Si/carbon nanotubes/cellulose composite anodes without adhesive and its electrochemical properties

Abstract

Silicon/carbon composite materials were widely considered as the next generation and the most potential anode materials. In order to reduce the huge expansion of silicon, avoid silicon nanoparticle powder and improve the electrochemical performance of silicon based lithium ion battery, a microporous structure paper of multiwalled carbon nanotubes(MWCNTs) was prepared, and the Si/MWCNTs/cellulose composite flexible lithium ion battery anode was prepared by embedding nanoscale silicon. FESEM shows that the nano-silicons are evenly inserted in the three-dimensional conductive network constructed by MWCNTs. This results in decreased interface resistance owing to increasing contact area between silicon and MWCNTs. The high hole of the anode provides enough space for expansion of silicon in cycles. So, the structural stability and chemical stability of the electrodes significantly are guaranteed. Electrochemical tests demonstrate that the first discharge capacity reaches 2024 mAh/g, and the capacity is still maintained at 850 mAh/g after 30 cycles, which shows good cyclic stability and high specific capacity. The unique electrodes show excellent electrochemical performance. The fabrication process of the electrode is much simpler than traditional coating process, strong maneuverability and a satisfactory prospect for industrial applications.

Keywords

• nano silicon
• multi walled carbon nanotube
• anode
• lithium ion battery