Manipulating Sulfur Redox Kinetics in Rechargeable Metal–Sulfur Batteries: Fundamental Principles and Universal Methodologies

The profound understanding of chemical reaction essence and kinetic behaviors is crucial to develop rechargeable battery technologies. Based on multi-electron conversion, sulfur redox reactions hold great promise for establishing low-cost, high-energy-density, and longstanding rechargeable batteries. However, the sulfur redox reaction processes suffer from a series of common daunting cruxes, leading to incomplete redox reactions and inferior battery performance when working in rechargeable batteries. These innate challenges of sulfur redox reactions include poor sulfur reactivity, sluggish charge transmission, severe polysulfide shuttling, high redox energy barrier, and undesirable reaction reversibility. Accordingly, it becomes a consensus to effectively manipulate sulfur redox kinetics for developing competent rechargeable metal-sulfur batteries. Herein, this review centers on sulfur redox reactions, within the compass of understanding electrochemical fundamentals, principles, thermodynamics, dynamics, and kinetics as well as emphatically presents universal methodologies to boost sulfur redox reaction kinetics in rechargeable metal-sulfur batteries. The unique viewpoint on sulfur redox reactions in rechargeable metal-sulfur batteries can provide a deepened understanding of sulfur electrochemistry and lead to new insights into the sulfur cathode designs and battery configurations, thus accelerating reaction kinetics of sulfur cathodes and promoting practical progress on high-energy-density battery technologies.