Polyoxometalate-Cyclodextrin-Based Cluster-Organic Supramolecular Framework for Polysulfide Conversion and Guest-Host Recognition in Lithium-sulfur Batteries

Angew Chem Int Ed Engl. 2023 Sep 4;62(36):e202306528. doi: 10.1002/anie.202306528. Epub 2023 Jul 31.

Abstract

Developing polyoxometalate-cyclodextrin cluster-organic supramolecular framework (POM-CD-COSF) still remains challenging due to an extremely difficult task in rationally interconnecting two dissimilar building blocks. Here we report an unprecedented POM-CD-COSF crystalline structure produced through the self-assembly process of a Krebs-type POM, [Zn2 (WO2 )2 (SbW9 O33 )2 ]10- , and two β-CD units. The as-prepared POM-CD-COSF-based battery separator can be applied as a lightweight barrier (approximately 0.3 mg cm-2 ) to mitigate the polysulfide shuttle effect in lithium-sulfur batteries. The designed Li-S batteries equipped with the POM-CD-COSF modified separator exhibit remarkable electrochemical performance, attributed to fast Li+ diffusion through the supramolecular channel of β-CD, efficient polysulfide-capture ability by the dynamic host-guest interaction of β-CD, and improved sulfur redox kinetics by the bidirectional catalysis of POM cluster. This research provides a broad perspective for the development of multifunctional supramolecular POM frameworks and their applications in Li-S batteries.

Keywords: Cluster-Organic Supramolecular Framework; Cyclodextrin; Lithium-Sulfur Batteries; Polyoxometalates; Polysulfide.