Improving the performance of Lithium-Sulfur Batteries using Sulfur-(TiO2/SiO2) yolk–shell Nanostructure

Abstract

Lithium-Sulfur (Li-S) batteries are considered as one of the promising candidates for next-generation Li batteries in near future. Although, these batteries are suffering from certain drawbacks such as rapid capacity fading during the charge and discharge process due to the dissolution of polysulfides. In this paper, Sulfur/metal oxide (TiO2 and SiO2) yolk–shell structures have been successfully synthesized and utilized to overcome this problem and improve the electrochemical performance of sulfur cahtode material. Prepared materials have been characterized using Scanning Electron Microscopy(SEM), Transmission Electron Microscopy(TEM) and X-ray diffraction (XRD) techniques. The results show significant improvement in the battery performance as a result of using Sulfur-SiO2 and Sulfur-TiO2 yolk–shell structures. The obtained Sulfur-TiO2 electrode delivers a high initial discharge capacity (>2000 mA h g−1) and discharge capacity of 250 mA h g−1 over 8 charging/discharging cycles with Coulombic efficiency of 60%, while initial discharge capacity for Sulfur-SiO2 electrode was lower (>1000 mA h g−1) compared to Sulfur-TiO2. Sulfur-SiO2 electrode shows the discharge capacity of 200 mA h g−1 over 8 charging/discharging cycles with Coulombic efficiency around70%. The obtained galvanostatic ressults demonstrated that Sulfur-TiO2 electrode possess stronger capability to prevent sulfur and its intermediate reaction products from dissolving into the electrolyte.