Engineering Cathode–Electrolyte Interphase for High‐Performance Li–S Batteries

Lithium–sulfur (Li–S) batteries exhibit notable advantages, such as lower cost, due to the abundance and affordability of sulfur, coupled with superior gravimetric and volumetric energy densities, ample sulfur reserves, and a reduced environmental footprint. These compelling attributes render Li–S batteries a highly promising energy storage technology, attracting significant global interest. However, their practical deployment is hindered by critical challenges at the cathode–electrolyte interface, including structural degradation (such as heterogeneous Li 2 S deposition), unstable interphase layers, and the detrimental lithium polysulfides shuttle effect. Addressing these issues requires concerted efforts to optimize both the electrode and interface to improve overall battery performance. This review systematically delineates these interfacial challenges and discusses corresponding mitigation strategies, with emphasis on electrolyte design to form stable cathode–electrolyte interphases, control Li 2 S deposition behavior, and suppress the shuttle effect through modulation of solid–liquid–solid reaction pathways, their transition to solid–solid conversion routes, and the optimization of solid–solid pathways themselves. Finally, the article offers key perspectives aimed at advancing the fundamental understanding of interfacial phenomena and designing stable battery configurations, with the ultimate goal of stimulating further research and accelerating the commercialization of Li–S batteries.