Aqueous Electrolytes for Lithium Sulfur Batteries

Lithium-sulfur (Li–S) battery shows the significant potential to fulfil the energy demand due to its extraordinary high energy density (1700 mAh g−1). However, the notorious shuttle effect and the high electrolyte/sulfur (E/S) ratio are of great challenge for the Li–S cell, which severely deteriorate the cycling stability and energy density. To receive a deep insight into the aforementioned problems, this chapter aims to unveil the underlying correlations among electrolyte component, microscopic solvation structure, dissolution of polysulfide, sulfide reaction steps, and electrochemical performance within three electrolyte system (moderately solvating system (MSS), poorly solvating system (PSS), and abundantly solvating system (ASS)). This chapter mainly focuses on the solution type and polysulfide solvation properties in different electrolyte system, and then highlight their critical effect on the cycling performance and E/S ratio. By delving into these relationships, the chapter seeks to provide a comprehensive understanding of how these factors interplay and the ways to improve the electrochemical performance of Li–S batteries.