Sulfur Cathode Design for Practical Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are promising candidates for energy storage owing to their high theoretical energy density and low cost. However, challenges remain due to inherent issues such as sluggish redox kinetics and the severe polysulfide shuttle effect of the sulfur cathode. It is essential to address these issues without compromising high gravimetric and volumetric energy densities for the commercialization of Li-S batteries. Furthermore, although Li-S batteries perform well at ambient temperatures, achieving reliable operation across wider temperature ranges remains challenging, which is crucial for future mission-specific applications. This review delves into advanced design strategies for sulfur cathodes of Li-S batteries, evaluating their influence on gravimetric energy density (Wh kg^-1), volumetric energy density (Wh L^-1), and wide-temperature performance. The key parameters of the sulfur cathode significantly relevant to practical application are discussed, including sulfur fraction, sulfur loading, electrolyte-to-sulfur ratio (E/S ratio), and the density of host materials. The aim is to bridge the gap between fundamental research and the practical realization of high-performance Li-S batteries. Finally, the prospects and future research directions toward achieving commercially viable Li-S cells with high-energy density and wide operational temperature capability are discussed.