A Supramolecular Capsule for Reversible Polysulfide Storage/Delivery in Lithium-Sulfur Batteries

Supramolecular materials, in which small organic molecules are assembled into regular structures by non-covalent interactions, attract tremendous interests because of their highly tunable functional groups and porous structure. Supramolecular adsorbents are expected to fully expose their abundant adsorptive sites in a dynamic framework. In this contribution, we introduced cucurbit[6]uril as a supramolecular capsule for reversible storage/delivery of mobile polysulfides in lithium-sulfur (Li-S) batteries to control undesirable polysulfide shuttle. The Li-S battery equipped with the supramolecular capsules retains a high Coulombic efficiency and shows a large increase in capacity from 300 to 900 mAh g⁻¹ at a sulfur loading of 4.2 mg cm⁻². The implementation of supramolecular capsules offers insights into intricate multi-electron-conversion reactions and manifests as an effective and efficient strategy to enhance Li-S batteries and analogous applications that involve complex transport phenomena and intermediate manipulation.