Edge-distributed iron single-atom moiety with efficient “trapping-conversion” for polysulfides driving high-performance of Li-S battery

Great efforts are exploring single-atom (SA) sites for tailoring catalytic effects on the sulfur-related redox reaction in Li-S battery, while edge-distributed SA sites lack attention. Herein, we implanted SA iron sites in N-doped porous carbon on CNTs (Fe-NPC@CNTs) to obtain edge-distributed FeN4 moieties via a polymer inductive strategy. The Fe-NPC@CNTs own enhanced “trapping-conversion” ability for polysulfides. The Li-S battery based on Fe-NPC@CNTs achieves a wonderful capacity of 1004 mAh g−1 at 1 C with long-term cycling stability, where the capacity fading rate is 0.032% per cycle over 1200 cycles. Noteworthy, the cell delivers very large capacities of 3.94/6.12 mAh cm−2 under high sulfur loadings of 4.50/5.04 mg cm−2 at 0.5/0.2 C, corresponding to 82.5/82.4% capacity retentions over 100 cycles. Under ultrahigh sulfur loadings (7.8/10.9 mg cm−2), the cell exhibits amazing large areal capacities of 7.63/10.76 mAh cm−2. The edge-distributed SA sites engineering provides a bright blueprint for advanced Li-S battery. [Display omitted] •Fe-NPC@CNTs has highly exposed edge-distributed Fe-N4 moieties.•Charge redistribution of Fe atoms is found for Fe-NPC@CNTs.•Enhanced “trapping-conversion” property for polysulfides is obtained for Fe-NPC@CNTs.•The Li-S battery employing Fe-NPC@CNTs demonstrates outstanding performance.