Untangling the design of single-atom Zn catalyst for superior performance in lithium-sulfur batteries

The sluggish kinetics of electrochemical reaction and the shuttle effect of sulfur species represent significant challenges hindering the advancement of lithium‑sulfur batteries (LiSBs). In this study, we propose a “tall building on flat ground” strategy to synthesize a single-atom Zn catalyst (MXene-NPC-Zn), where nitrogen-doped porous carbon (NPC) serves as the “tall buildings”, while MXene acts as the foundational “flat ground” supporting the porous carbon. This engineered microstructure provides a large surface area for the deposition of electrochemically inert sulfur and Li₂S while effectively stabilizing Zn single atoms. The incorporation of Zn single atoms enhances catalytic activity, accelerates sulfur species conversion, and facilitates rapid electron transport and efficient lithium-ion transfer during charge-discharge cycles. Consequently, LiSBs with the MXene-NPC-Zn modified separator achieve a high reversible capacity of 1407.3 mAh g −1 at 0.2C and exhibit stable cycling performance at 1C with a low-capacity decay of 0.071 % per cycle. These findings underscore the potential of the single-atom catalyst, synthesized using the “tall building on flat ground” approach, as a promising material for improving the performance of LiSBs.