Kinetically Favorable Li-S Battery Electrolytes

Lithium-sulfur (Li-S) batteries suffer from rampant polysulfide shuttling and sluggish reaction kinetics, which have curtailed sulfur utilization and deteriorated their actual performance. To circumvent these detrimental issues, electrolyte engineering is a reliable strategy to control polysulfide behavior and facilitate reaction kinetics. However, the electrolyte-polysulfide nexus remains elusive, and the electrolyte design principle is far from clear, especially for pragmatic application. In this Review, key approaches to obtain kinetically favorable Li-S battery electrolytes are elucidated from three perspectives: (i) high-donor-number components, (ii) homogeneous catalysts, and (iii) endogenous co-mediators. Particular attention is paid to probing the underlying working mechanism. In addition, reaction kinetics and electrochemical performances are systematically studied, especially highlighting the strategic effectiveness of kinetically favorable Li-S battery electrolytes in lean-electrolyte conditions. This Review aims to offer meaningful guidance for the rational design of kinetically favorable electrolytes to enhance the performance and advance the commercialization of Li-S batteries.