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.