Developing highly solvating electrolyte solutions for lithium–sulfur batteries

The limited polysulfide solubility and the resulted poor kinetics in conventionally preferred electrolyte solutions severely limit the energy density of lithium–sulfur (Li–S) battery under practically lean-electrolyte conditions. Recently, highly solvating electrolyte solutions (HSEs) have been proposed to tackle the challenge because of their high polysulfides solubility. Despite the promised high capacity under lean-electrolyte conditions, the sulfur reaction pathways, the kinetics and the reactivity with lithium remain the major questions regarding this path. This opinion is positioned to summarize the recent progress on developing HSEs for Li–S battery, aiming to call for attention from the community. We also offer our opinions on whether HSEs are promising and how to improve them for future Li–S battery. We anticipate that the electrolytes strategy that promises high-capacity/high energy Li–S batteries by using HSEs should be further developed to enable stable and reversible behavior of Li anodes, thus benefiting from both energy content and durability.