Spin state modulation on dual Fe center by adjacent Ni sites enabling the boosted activities and ultra-long stability in Zn-air batteries.

This work proposes a strategy to tailor the electron spin states of dual-metal-atom Fe 2 N 5 via the introduction of neighboring single-metal-atom NiN 4 sites, which enables it with superior ORR activities and ultralow HO 2 − yield that could avoid the occurrence of Fenton reaction, thus hitting the spot of ultra-long-term stability over 1200h for ZABs. [Display omitted] Breakthrough in developing cost-effective Fe-based catalysts with superior oxygen reduction reaction (ORR) activities and ultra-long-term stability for application in Zn-air batteries (ZABs) remain a priority but still full of challenges. Herein, the neighboring NiN 4 single-metal-atom and Fe 2 N 5 dual-metal-atoms on the N-doped hollow carbon sphere (Fe/Ni-NHCS) were deliberately constructed as the efficient and robust ORR catalyst for ZABs. Both theory calculations and magnetic measurements demonstrate that the introduction of NiN 4 provides a significant role on optimizing the electron spin state of Fe 2 N 5 sites and reducing the energy barrier for the adsorption and conversion of the oxygen-containing intermediates, enabling the Fe/Ni-NHCS with excellent ORR performance and ultralow byproduct HO 2 − yield (0.5%). Impressively, the ZABs driven by Fe/Ni-NHCS exhibit unprecedented long-term rechargeable stability over 1200 h. This work paves a new venue to manipulate the spin state of active sites for simultaneously achieving superior catalytic activities and ultra-long-term stability in energy conversion technologies. [ABSTRACT FROM AUTHOR]