A Supramolecular Complex of C60 -S with High-Density Active Sites as a Cathode for Lithium-Sulfur Batteries.

ABSTRACT

The well-known "shuttle effect" of the intermediate lithium polysulfides (LiPSs) and low sulfur utilization hinder the practical application of lithium-sulfur (Li-S) batteries. Herein, we describe a novel C60 -S supramolecular complex with high-density active sites for LiPS adsorption that was formed by a simple one-step process as a cathode material for Li-S batteries. Benefiting from the cocrystal structure, 100 % of the C60 molecules in the complex can offer active sites to adsorb LiPSs and catalyze their conversion. Furthermore, the lithiated C60 cores promote internal ion transport inside the composite cathode. At a low electrolyte/sulfur ratio of 5 µL mg-1 , the C60 -S cathode with a sulfur loading of 4 mg cm-2 exhibited a high capacity of 809 mAh g-1 (3.2 mAh cm-2 ). The development of the C60 -S supramolecular complex will inspire the invention of a new family of S/fullerenes as cathodes for high-performance Li-S batteries and extend the application of fullerenes.