Accelerating Redox Kinetics of Lithium-Sulfur Batteries

It is critical to suppress the shuttle effect and increase sulfur utilization through designing host materials that can not only adsorb lithium polysulfides (LiPSs) but also catalyze their conversion. Catalytic materials for accelerating the sulfur redox reaction include metal-free polar materials, transition-metal compounds, and metals. The design of catalytic materials should consider the balance of LiPS trapping ability, surface reactivity, diffusivity of lithium ions and LiPSs, and electrical conductivity. Lithium-sulfur (Li-S) batteries exhibit great promise for next-generation energy storage due to their high theoretical energy density and low cost. However, their practical application is largely hindered by the shuttle effect. Although previous studies on the adsorption of lithium polysulfides (LiPSs) have achieved significant progress, simple adsorption cannot fundamentally eliminate the shuttle effect. Physical and chemical confinement are useful to anchor LiPSs to some extent, but these are not effective for utilizing the blocked intermediates. Accordingly, accelerating polysulfide redox kinetics is crucial to radically mitigate the shuttle effect and increase sulfur utilization. Herein, recent advances in catalysts for boosting redox kinetics of Li-S batteries are reviewed. We also provide prospects on the design of more efficient catalysts for Li-S batteries. Lithium-sulfur (Li-S) batteries exhibit great promise for next-generation energy storage due to their high theoretical energy density and low cost. However, their practical application is largely hindered by the shuttle effect. Although previous studies on the adsorption of lithium polysulfides (LiPSs) have achieved significant progress, simple adsorption cannot fundamentally eliminate the shuttle effect. Physical and chemical confinement are useful to anchor LiPSs to some extent, but these are not effective for utilizing the blocked intermediates. Accordingly, accelerating polysulfide redox kinetics is crucial to radically mitigate the shuttle effect and increase sulfur utilization. Herein, recent advances in catalysts for boosting redox kinetics of Li-S batteries are reviewed. We also provide prospects on the design of more efficient catalysts for Li-S batteries.