Lean-electrolyte lithium-sulfur batteries: Recent advances in the design of cell components

Lithium-sulfur batteries (LSBs) have attracted considerable attention as next-generation secondary battery due to their significantly higher theoretical energy density (2,600 Wh kg-1) compared to that of commercialized lithium-ion batteries (LIBs). In the last decade, most of the achievements in LSBs were attained based on excessive electrolyte usage. However, high electrolyte/sulfur ratio (E/S ratio) conditions degrade not only cost competitiveness but also actual energy density, eventually hindering the commercialization of LSBs. Therefore, it is essential to develop lean-electrolyte LSBs exhibiting excellent performance with advanced components even under harsh internal environments. In this perspective, this review focuses on the state-of-the-art advances of LSBs under lean electrolyte conditions and categorizes imperative strategies to overcome its serious problems.