Sun Hyu Kim1,Ji Yang Lim1,Si Won Choi1,Sandeul Ryoo1,Hye Ran Kim1,Yongju Jung1
Korea University of Technology and Education1
Sun Hyu Kim1,Ji Yang Lim1,Si Won Choi1,Sandeul Ryoo1,Hye Ran Kim1,Yongju Jung1
Korea University of Technology and Education1
Lithium-sulfur (Li-S) batteries have garnered significant attention as a promising energy storage system owing to the high energy density and high natural abundance of sulfur. Nonetheless, their practical application has been slowed down by limited cycle life attributed to soluble polysulfide species generated on discharge. The migration of these dissolved polysulfide ions towards the lithium anode gives rise to the formation of inert materials on its surface. The solubility of polysulfides is necessary for the discharge-charge process of the sulfur cathode, so it is inevitable to effectively confine them within the cathode to protect the diffusion phenomena of polysulfide out of cathode. Several approaches have been proposed, such as the utilization of sulfur-infiltrated carbon nanotube (CNT) films. However, the macro-porous structure of CNTs limits their ability to effectively accumulate polysulfides. Another strategy involves incorporating ordered mesoporous silica (OMS) as an additive to mitigate the diffusion of polysulfides, yet OMS lacks long-term stability as a polysulfide reservoir. To address these limitations, this study introduces a novel solution for effectively immobilizing polysulfides. It entails the synthesis of carbon-layered OMS (c-OMS) through surface-selective polymerization inside silica mesopores, followed by carbonization. Comparing the performance of the sulfur-CNT cathode with c-OMS to that of the sulfur-CNT cathode alone, the former demonstrates a significantly enhanced capacity (942 mAh/g) and superior cycle stability (91% retention after 100 cycles). These outcomes underscore the advantageous surface properties of c-OMS, which exhibit a high chemical affinity for electrolyte solvents. This research presents a promising approach for enhancing the performance of Li-S batteries by effectively addressing issues related to polysulfide dissolution and confinement.