Supramolecules Applied to Energy Storage Devices: Study on the Mechanism of Cucurbituril Inhibition of the Polysulfide Shuttle Effect

Abstract Lithium‐sulfur (Li‐S) batteries are considered promising candidates for next‐generation high‐energy‐density storage devices; however, their commercialization remains hindered by several challenges. Supramolecular macrocyclic compounds, owing to their unique structures and properties, hold significant potential for improving Li‐S battery performance. In this study, the inclusion mechanism of lithium polysulfides (LiPSs) by cucurbiturils (CB[n], n = 6,7) was systematically investigated. Density functional theory (DFT) calculations were employed to analyze the recognition capabilities of CB[6] and CB[7] for polysulfides. The results indicate that both CB[6] and CB[7] effectively encapsulate polysulfides through non‐covalent interactions. Specifically, CB[6] exhibits a stronger affinity for medium‐chain sulfur species, with the most pronounced encapsulation observed for Li 2 S 4 . In contrast, CB[7] demonstrates superior encapsulation efficiency for longer‐chain sulfur species, with the most stable inclusion occurring for Li 2 S 6 . Furthermore, molecular dynamics (MD) simulations based on DFT calculations revealed that Li 2 S 4 @CB[6] and Li 2 S 6 @CB[7] exhibit high stability in battery electrolytes. These findings suggest that CB[6] and CB[7], as supramolecular materials, can effectively inhibit the dissolution and migration of polysulfides in Li‐S batteries, mitigating the “shuttle effect” and significantly enhancing battery cycle life and charge‐discharge efficiency. This research provides valuable insights into the optimization of materials for Li‐S battery applications.