Multitype Interaction Between a Redox‐Active Inclusion Complex, Polymer, and Polysulfides that Boosts the Performance of Lithium–Sulfur Batteries

Polysulfides formed in Li–S batteries pose various characteristics. For example, Li 2 S is solid while Li 2 S 4 is liquid. Li 2 S is insoluble in battery electrolytes while Li 2 S 4 is soluble. All of them are negative charge bearing molecules. Lithium polysulfides are Lewis acids. Herein, a binder with multiple interaction motifs is presented to confine the polysulfides in the cathode. The base of the binder is sodium salt of carboxy methyl cellulose (CMC). β ‐cyclodextrin (CD) that comprises 21 hydroxyl groups is used because they hydrogen bond with the carboxylate moieties of CMC to impart mechanical strength to the binder to accommodate volume change during the sulfur to polysulfide conversion. Indeed, it is found that the binder with CD shows improved mechanical properties compared to CMC. The cavity of the CD is used to prepare an inclusion complex with ferrocene methanol. Due to the presence of Fe 2+ , the batteries comprising the inclusion complex show improved electrocatalytic properties. The Li–S batteries deliver a specific capacity of 780 mA h g −1 (1 C) at a high sulfur loading of 4.7 mg cm −2 and lean electrolyte (E/S of 5 μL mg −1 ).