Improved Cycling Performance of Lithium–Sulfur Cell through Supramolecular Interactions

Abstract

Commercialization of lithium–sulfur batteries is plagued by poor electronic conductivity of elemental sulfur, shuttling of polysulfides, and poor interfacial properties of lithium metal anodes with nonaqueous electrolytes. Although numerous attempts have been made to alleviate such challenges, trapping of polysulfides within sulfur composite cathodes appears as an efficient way to improve the cycling performance of Li–S cells. In the present work, naphthyl viologen was successfully synthesized and incorporated in a sulfur cathode in order to enhance the electrochemical performance of Li–S cells. Charge–discharge studies revealed that the viologen-added Li–S cell delivered higher discharge capacity than the unladen one. The enhanced performance of viologen-laden sulfur cathode was attributed to the electrostatic interaction between polysulfide and viologen, which was further substantiated by UV–vis spectroscopy.