Synthesis and Electrochemical Performance of Graphene @ Halloysite Nanotubes/Sulfur Composites Cathode Materials for Lithium-Sulfur Batteries

Abstract

Natural halloysite nanotubes (HNTs) and reduced graphene oxide (RGO) were introduced into the S cathode material to form HNTs/S and RGO@HNTs/S composite electrode to improve the electrochemical performance of Li-S batteries. The effect of acid etching temperature on the morphology and pore structure of HNTs was explored and the morphological characteristics and electrochemical performance of composite electrodes formed by HNTs that after treatment with different acid etching temperatures and RGO were compared. The result shows that the cycling stability and the utilization rate of active substances of the Li-S battery were greatly improved because the pore structure and surface polarity functional groups of HNTs and the introduction of RGO provide a conductive network for insulating sulfur particles. The RGO@HNTs treated by acid treatment at 80 °C (RGO@HNTs-80/S) composite electrode at 0.1 C has an initial capacity of 1134 mAh g−1, the discharge capacity after 50 cycles retains 20.1% higher than the normal S electrode and maintains a specific discharge capacity of 556 mAh g−1 at 1 C. Therefore, RGO and HNTs can effectively improve the initial discharge specific capacity, cycle performance and rate performance of Li-S batteries.