Intermolecular adsorption-pairing synergy for accelerated polysulfide redox reactions towards lithium-sulfur battery with high stability

Rational design of heterostructure which integrate adsorption and catalysis has been considered as an effective method for shuttle effect and slow kinetics of polysulfides. However, the synergy involved in most studies requires the transfer of polysulfides (Li2Sx, 4 ≤ x ≤ 8) from one site to another relatively distant site, which is low-efficient and slow. Herein, a novel synergistic strategy (adsorption-pairing) is proposed for the first time to promote polysulfides conversion by tight intermolecular synergy. We speculate that amide groups adsorb polysulfides first, and then the anchored polysulfides are paired with the adjacent zwitterionic structures to form two cation-anion pairs (imidazole ring[+]-Sx2−[-] and Li+[+]-sulfonate[-]). Unique ion pairing could elongate the Li-S bonds from two directions at the same time. The synergistic process between close groups ensures that the anchored polysulfides could be further catalyzed and anchoring site could be vacated for the unanchored polysulfides, which is efficient and fast. The Li-S batteries exhibits outstanding cycling performance over 500 cycles with the capacity retention of 91.4% and favorable rate capability up to 4 C. This work provides a new insight in the synergistic effect for integrated adsorption and catalytic ability and constructs an ideal interfacial environment to lithium-sulfur chemistry.