Synthesis, properties and electrochemical characteristics of SiNPs/CNT/rGO composite films for the anode material of Li ion batteries

Abstract

In this study, we synthesized a composite film with silicon nanoparticles (SiNPs)/carbon nanotube (CNT)/reduced graphene oxide (rGO) using a simple dispersion technique and physical filtration. The composite film was applied as a self-supporting and binder-free anode material for high-performance lithium ion batteries. SiNPs were uniformly coated on thermally reduced graphene oxide and CNTs surround the surface of the SiNPs coated with graphene. The reduced graphene oxide provides a matrix with sufficient space that can accommodate the volume change of SiNPs during lithiation/delithiation and improves the electronic conductivity. In addition, CNTs maintain a stable structure to prevent the separation of SiNPs from the electrode. The films were prepared by adjusting the volume of dispersion to 20, 25, and 30 mL to compare electrochemical performance. In particular, the SiNPs/CNT/rGO-25 mL electrode maintained a capacity of 198 mAh/g even after 30 cycles. These results show that the CNTs act as a crosslinker in the three-dimensional structure of SiNPs and graphene, thereby preventing graphene from being desorbed during the volume change of Si. It improves the conductivity, leading to high capacity and stable cycling performance. Moreover, this structure provides an efficient channel for the rapid transport of electrons and ions.