Progress in Mechanistic Understanding and Characterization Techniques of Li-S Batteries

Rechargeable lithium-sulfur batteries that operate at room temperature have attracted much research interest as next-generation energy storage systems. Although tremendous advances have been made with Li-S batteries, great challenges still exist in achieving high capacity, high loading, high coulombic efficiency, and long cycle life. These challenges arise from the system complexity, lack of mechanistic understanding of the redox reaction, and operational limitations of Li-S cells. The focus here is on the recent gains in fundamental understanding of the Li-S redox reaction mechanism based on the application of advanced characterization techniques. Research results that help with the understanding of the close relationship between cell design (including development of new and advanced electrode materials, electrolytes, separators, binders, and cell configurations), the Li-S reaction mechanism, characterization methods, and Li-S battery performance are discussed.