Rational Designs of Single-Atom Catalysts Loaded Hollow Microstructures for Advanced Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) are promising next-generation energy storage candidates with high theoretical specific capacity and low material cost. Despite these advantages, the practical application of LSBs is significantly hampered by the lithium polysulfides (LiPSs) shuttle effect, poor sulfur conductivity, and sluggish LiPSs conversion kinetics. Numerous studies have confirmed that introducing catalysts to LSBs effectively addresses the sluggish conversion of LiPSs. Single-atom catalysts (SACs) have demonstrated great potential in LSBs due to their high catalytic activity and nearly complete atom utilization. The synergistic effect of the hollow structure and the SACs addresses key limitations of SACs in LSBs, including agglomeration, insufficient LiPSs confinement, and poor volume buffering capability. Thus, SACsloaded hollow microstructures (SACs-HMs) are a superior strategy to address the LiPSs shuttle in LSBs. In this review, we first discuss the mechanistic roles and inherent challenges of SACs in suppressing the LiPSs shuttle. Subsequently, the structure-activity relationships of three hollow configurations (single, double, and yolk-shell) are comprehensively compared, highlighting their distinct impacts on battery performance. And we evaluate four synthesis methods (hard-template, soft-template, template-free, and self-template), outlining their respective advantages and limitations for crafting SACs-HMs. Lastly, a perspective on the future developments of SACs-HMs in LSBs applications is offered.